Scientia
The Baylor Undergraduate Research Journal of Science & Technology
Original Research
Review Articles
College of Arts & Sciences
Abstracts
Spring 2015 SPRING 2015
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EDITORIAL BOARD
Mallory Myers and Peter Jiang
STUDENT EDITORS
Nitheesha Alapati, Aparna Konde, Krystal Miller, and Savan Patel
DESIGN STAFF
Jade Connor and Aparna Sarode
ADVISORY BOARD
Dean Frank Mathis, Ph.D. and Dean Elizabeth Vardaman, M.A.
SPECIAL THANKS TO:
Dean Lee Nordt, Ph.D. and the Baylor University College of Arts & Sciences
ON THE COVER: Top Left: Senior Gerardo Martinez checks on his zebrafish as part of his duties in Dr. Usenko’s lab. Top Right: A researcher performs mass spectrometry in Dr. Solouki’s lab. Bottom Left: A researcher swabs plated nose samples to test for staph and MRSA. Bottom Right: Senior Regina Martinez explains her research to curious students during URSA Scholars Week.
ON THIS PAGE: Top: Senior Katie Rodriguez analyzes a specimen in Dr. Hotez’s lab at Baylor College of Medicine. Middle: Now Baylor alum David Dreier explains his research to Dr. Bratton during the 2014 URSA Scholars Week. Bottom: Students learn more about biochemistry research at an Advanced Instrumentation Workshop.
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IN THIS ISSUE
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From the BURST Officer Team: Why Research Matters
ORIGINAL RESEARCH
ABSTRACTS
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EDTA Assisted Phytoremediation of Copper by Cattail Plants
37
Investigating an ESKAPE to Nosocomial Infections
13 19
The Effects of Varying Burn Intensities on Plant Growth
38
Risk Factors Associated with Post-Operative Nausea and Vomiting
Caputo, B.; Gleason, K.; Albo, C.; Harvill, M., Ph.D.
Teague, T.; Bowersox, J.; Reeves, K.
Studies of Synthetic Hydroxyheme and Heme Oxygenase Martinez, R.; Clover, T., M.S.; Farmer, P., Ph.D.
REVIEW ARTICLES
22 30
The Path to Vascular Dementia via Autoimmunity: A Review Le, D.; Scullin, M., Ph.D.
Curtis, K.; Hartman, D. D.V.M.; Duke, J., PhD
Martin, M.
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2015 URSA Scholars Week Award Winners in STEM
44 ABOUT THE AUTHORS
Guanfacine Extended-Release: A Non-Psychostimulant Drug Treatment for Attention Deficit/ Hyperactivity Disorder Olmstead, J.
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Introduction
From the BURST Officer Team: Why Research Matters
Tanner Hood*, Conner Reynolds*, Ahsan Ali, Jade Connor, Mallory Myers, Aparna Sarode, Brittney Tew, Dominic Edwards, and Meagan Volquardsen Baylor University, Waco, Texas Abstract
The aim of this study was to gain perspective on Baylor undergraduate STEM students’ awareness of, attitudes toward, and involvement in undergraduate research experiences (UREs). BURST (Baylor Undergraduate Research in Science and Technology) leaders partnered with Baylor University Student Government to distribute an online survey to students. Questions pertaining to research required yes/no or 1-10 rating scale responses. The results indicated that students believe UREs are essential to undergraduate education (7.76/10) and that students would benefit from more research opportunities (8.66/10). However, fewer students thought research was well-advertised (5.41/10) or knew how to become involved in research (6.26/10). Only 31% of STEM respondents have participated in research; of those, 86% have participated in research at Baylor and 40% have participated in research at an external institution. Those students believe that their UREs have prepared them for the future (7.70/10) and that they have learned skills that cannot be taught in the classroom (8.13/10). Collectively, these results demonstrate that UREs are important to Baylor undergraduate students, but improvements can be made in their advertising and availability. Suggestions for improving UREs at Baylor include increasing summer research opportunities, improving advertising from academic departments, encouraging professors to support student involvement in their current research, and making UREs a required component of STEM degrees. This survey could be used annually to assess how well Baylor’s administration, staff, and students are promoting the growth of Baylor’s research community.
Introduction
For students, administrators, graduate and professional school admissions boards, and employers, research is gaining priority in undergraduate education. Data from a 2007 study suggests that approximately 53% of undergraduate STEM students have participated in some form of research.5 Undergraduate research experiences (UREs) benefit students in both the short and long term. Although it is becoming more common, engaging in research as an undergraduate remains a challenging endeavor. Many students have misconceptions about what research entails. A recent survey found that students completing their first URE found research to be more tedious and less exciting than they expected. They also felt that their mentors were not available or approachable enough to guide them through the challenges of doing research for the first time.1 However, 4
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it is typically not until the third semester of UREs that students are able to independently grasp research techniques, conduct projects, and comprehend the significance of their data. For this reason, sustained research has been shown to provide greater benefits to students than sporadic research.3 After their URE, students in one study reported improvements in research methods and techniques, as well as an increased understanding of what a career in research entails. UREs also immerse students in a collaborative environment where they learn how to work alongside others toward a common goal of scientific progress. The advantages of research extend to the classroom, where students benefit from an increased volume of scientific knowledge and better learning strategies that enhance academic performance and reduce test-taking anxiety.1 In the long term, UREs
have been shown to foster creativity, critical thinking, and decision making,2 skills vital not only to the STEM field but to any occupation. In response to the known benefits of undergraduate research, Baylor University’s administration has intensified its efforts to connect its students with UREs. The College of Arts and Sciences’ goal is to increase research in the STEM fields, humanities, and social sciences, and become a Carnegie Research University with a “very high research activity” designation.4 The aim of this study was to gain perspective on Baylor undergraduate STEM students’ awareness of, attitudes toward, and involvement in UREs. The results could serve as a foundation for future initiatives to improve UREs at Baylor.
Methods
In order to properly assess the research experiences of undergraduate students at Baylor University, a survey was constructed using Qualtrics, an online survey software program. Survey questions collected information on the level of student interest, opportunity awareness, and the quality of research experiences. For a list of survey questions, please see Appendix A. In partnership with Baylor University Student Government, the survey was distributed through multiple online outlets. This included an email to undergraduate students from the Student Body President as well as advertising on affiliated social media sites such as Facebook and Twitter. The survey was active for student input from January 31 at 11:59 PM (CST) to February 22 at 11:59 PM (CST) of 2015. In this time it generated 548 completed responses. Quantitative analyses of survey findings have been computed and displayed through the collaboration of Qualtrics and GraphPad Prism.
Results
In this study, STEM students were first asked general questions regarding undergraduate research at Baylor University. Possible ratings for each of these questions ranged from 1-10. When students were asked whether research experiences were essential to undergraduate education, the mean score was 7.76 ± 2.07 units. When students were asked whether they had personal interest in research experiences within their degree program, the mean score was 8.06 ± 2.22 units. When students were asked whether students would benefit from more research opportunities, the mean score was 8.66 ± 1.58 units. When students were asked whether research
opportunities were well advertised, the mean score was 5.41 ± 2.19 units (Figure 1). Lack of advertising and other resources for undergraduate research may be limiting students’ involvement in undergraduate research. To gain insight on whether this is the case, students were then asked how aware they were of becoming involved in research. The mean score was 6.26 ± 2.45 units (Figure 1). Student responses to these questions indicate that a lack of advertisement may be contributing to a low awareness of how to become involved in research. Students were then asked to provide whether they have been involved in research during their time as an undergraduate student. Responses to this question revealed that the population of STEM students who have actually participated in research is approximately 31% (Figure 2a.) Two follow up questions then asked only students who had participated in research to determine where their research experiences occurred. Responses to this question revealed that 86% of these students have participated in research at Baylor (Figure 2b), and 40% have participated in research at an external institution (Figure 2c). This means that, on average, approximately 27% of STEM students have participated in some sort of research on campus and 12.4% have gained experience elsewhere. Students who have participated in research were then asked to rate how much research has benefitted them personally. When asked whether their research experiences at Baylor were meaningful and constructive, the mean score was 8.03 ± 2.07 units (Figure 3). When asked whether their research experiences at Baylor have prepared them for the future, the mean score was 7.70 ± 2.62 units (Figure 3). When asked whether they have learned skills through research that cannot be taught in the classroom, the mean score was 8.13 ± 2.24 units (Figure 3). These data suggest that research experiences are invaluable to the undergraduate experience, but they are only available to a small fraction of STEM students.
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Figure 1. Baylor STEM student perception of Baylor undergraduate research based on 1-10 scale rating responses.
Figure 2. Percentage of Baylor undergraduate STEM students who have (A) performed research, (B) performed research at Baylor, and (C) performed research outside of Baylor.
Figure 3. Baylor STEM student perception of the benefits of UREs based on 1-10 scale rating responses.
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Discussion
The survey results revealed many areas of focus that, if altered, may improve Baylor students’ attitudes toward and involvement in UREs. Compared to other universities, the proportion of students involved in research at Baylor, as reported in our study, is well below the 2007 national average (31% versus 53%).5 Suggestions for improvement include increasing summer research opportunities, improving advertising from academic departments, encouraging professors to support student involvement in their current research, and making UREs a required component of STEM degrees. One method Baylor could utilize to stimulate research participation would be to encourage summer research projects. Given the time-intensive nature of research, the prospect of conducting research during the summer may be more enticing to students than balancing research and classes during the semester. As Figure 1 shows, students felt that advertisements for research opportunities were not as effective as desired. This may be due to a lack of advertising across the university, or inconsistencies in the level of advertising amongst departments. Some departments utilize multiple advertising outlets such as flyers, social media, emails, and word of mouth, while the UREs in other departments are less openly marketed. Consistent advertising across different departments that explicitly provide descriptions and requirements of UREs may help increase involvement in research. One of the most direct ways to improve Baylor’s UREs is for professors and other research staff to assume a more active role in recruiting students. Figure 2 demonstrates that students desire to participate in research, but are confused about how to start. If professors discussed their research in class, were explicit with their expectations, and notified promising and qualified students of openings in their labs, students would have more clarity on how to begin working in labs. In turn, the professors could then be more discriminating in their selection of undergraduate assistants, as they would have a larger pool of interested students to choose from. As demonstrated by Figure 2, 40% of research participants indicated that they have participated in UREs somewhere other than Baylor University. While this statistic includes all experiences from outside of Baylor, such as clinical research conducted at non-academic institutions, it is likely that some experiences took place at other universities. Additional inquiry is warranted in order to determine why a significant
percentage of Baylor students pursue research elsewhere. One possible reason is the appeal of summer research programs that are not currently offered at Baylor, such as Amgen Scholars, Summer Undergraduate Research Fellowships (SURFs), and other similar programs offered by major research universities. If Baylor were to create an on-campus summer research program, it would not only expand the opportunities available to current Baylor students, but it would also serve to advance Baylor’s reputation as a premiere research university by offering opportunities to talented students from other universities While there is significant ground to cover with improving advertising and access to research, Baylor’s greatest strength lies in the excellent quality of the UREs it currently provides. As demonstrated by Figure 3, of the students who have been involved in research, an overwhelming majority cited their UREs as being meaningful, constructive, and having provided them with skills that cannot be taught in the classroom. These skills will aid in future endeavors, whether that be attending graduate or professional school, or entering a STEM-related career. It is essential that all undergraduate students are made aware of how to become involved in the same experiences that are reviewed so highly by their peers. In the long term, Baylor’s administration could acquaint more undergraduate students with research by making it a graduation requirement for STEM degrees. This would drive students to actively seek out research and encourage professors to facilitate student participation in their research projects. A system similar to Hire-a-Bear (Baylor’s job opportunities database) for research positions could easily connect professors and students based on similar research interests. This may, however, require more research faculty to be hired in order to meet the demands of a large pool of students actively seeking research opportunities. Alternatively, a new department dedicated to advertising and creating UREs could undertake hiring more research faculty and maintaining a transparent online database like Hire-a-Bear. Another possible approach to integrating UREs into STEM degree requirements would be to introduce more introductory research courses. Baylor currently offers a class, BIO 1405 – Investigations of Modern Biology Concepts I, which teaches freshmen basic research skills and knowledge. However, as the class has twenty-four spots, only a few students gain exposure SPRING 2015
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to research. An increased number of courses similar to BIO 1405 would allow more students to gain experience in research and help them decide whether or not research is right for them. Additionally, the statistics courses required for most Baylor STEM degrees could help improve students’ understanding of the importance of correct statistical analysis in research. While Baylor statistics courses already provide a solid foundation in statistics theory and practice, they could go a step further by teaching students how to correctly interpret the statistics in research articles and how draw the proper conclusions from their own raw data. Such invaluable skills will make Baylor students more competent and confident in performing research, which may in turn drive them to seek out research opportunities. The conclusions drawn from this study aim to improve Baylor as a research university in accordance with its Pro Futuris vision. The survey could be used annually to assess how well Baylor’s administration, staff, and students are promoting the growth of Baylor’s research community. Given how highly Baylor students value research and desire to engage in UREs, Baylor has great potential to become a top-ranked undergraduate research institution.
References
1. Gardner, G. et al. Authentic science research opportunities: how do undergraduate students begin integration into a science community of practice? J Coll Sci Teach. 2015, 44, 61. 2. Hunter, A. et al. Becoming a scientist: the role of undergraduate research in students’ cognitive, personal, and professional development. Sci Ed. 2006, 37, 74. 3. Linn, M. et al. Undergraduate research experiences: impacts and opportunities. Science. 2015, 627, 640. 4. Nordt, L. et al. A&Spire: Acts of Determination in Support of Pro Futuris. Baylor University. 2014. 5. Russell, S. et al. The pipeline: benefits of undergraduate research experiences. Science. 2007, 548, 549.
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Appendix A
Demographic Questionnaire
Baylor ID What is your gender? What is your classification? (By number of years at Baylor) To which degree program does your major belong? Are you part of a Pre-Professional Program? Are you part of the Honors College?
Research Questionnaire
Research experiences are essential to your undergraduate education. (1-10) Baylor students would benefit from more research opportunities. (1-10) Undergraduate research opportunities are advertised well to all students. (1-10) I am aware of how to become involved in research. (1-10) I am interested in participating in research. (1-10) Excluding class projects, have you been involved in research during your time as a student? (Y/N) Have you been involved in research somewhere other than Baylor University? (Y/N) Have you participated in undergraduate research at Baylor University? (Y/N) My research experiences at Baylor were meaningful and constructive. (1-10) My research experiences at Baylor have prepared me for the future. (1-10) I have learned skills through research that cannot be taught in the classroom. (1-10)
Original Research
EDTA Assisted Phytoremediation of Copper by Cattail Plants
Ben Caputo, Kathryn Gleason, Camila Albo, and Marty Harvill, Ph.D. Department of Biology, Baylor University, Waco, Texas Abstract
The purpose of this experiment was to determine the efficacy of introducing the chelating agent ethylenediaminetetraacetic acid disodium salt dihydrate (Na2H2 EDTA) to wetland southern cattail (Typha domingensis) during its phytoremediation of Copper (Cu2+). Phytoremediation is a process used by plants to fix and subsequently sequester metals from contaminated soil matrix and soil solution.8 Plants detoxify contaminated soil and water by synthesizing phytochelatins, which sequester and transport metal contaminants into root cell vacuoles.5,6 As a result, Na2H2 EDTA acts as a phytochelatin by forming a complex ion [Cu(EDTA)]2- with various metallic soil contaminants such as Cu2+. In this experiment, the concentration of Cu2+ was measured using a DR/890 colorimeter. The complex ion concentration [Cu(EDTA)]2- continually increased over a three week time span indicating that Na2H2 EDTA may not serve as a potential source to enhance southern cattail’s uptake of heavy metals by acting as a metallic translocator. These results suggest that further scientific investigators may consider discarding the use of chelator-induced phytoremediation to remove heavy metals from water sources to improve the purity of daily resources commonly used in a clinical setting. (Key words: phytoremediation, EDTA)
Introduction
Developing cost-effective ways of removing heavy metal contaminants from wastewater is a topic of global interest.3 Due to the rapid expasion of the mining and agriculatural industry, metallic toxins continue to accumulate in our biosphere. This industrial expansion has caused heavy metals to accumulate on surface strata. The accumulation of metal toxins in water poses a harm to humans because they interfere with many biological metabolic processes and resist chemical oxidation.2 For example, copper toxicity is associated with Alzheimer’s disease because it reacts with amyloid beta proteins to produce unstable oxygen species in the brain.2 Since water purification is critical to maintaining low concentrations of chemical pollutants such as copper, a solution is needed. A viable solution to this cyclical threat is found in the natural process of phytoremediation.4 Plants that perform phytoremediation such as southern cattail (Typha domingensis) have recently been discovered to tolerate high levels of various trace elements, which make them a cost-effective source to eradicate the aggregation of metallic toxins.1 Cattail have many important health implications in pharmaceutical
and waste-removal industries. For example, cattail have been known to eradicate chemicals in degraded lands polluted with explosives. Cattail have also been known to purify runoff water by nuetralizing the acidic character of heavy metals – these may include aluminum, iron, lead and mercury.3 In fact, plants naturally detoxify contaminated soil and water by synthesizing phytochelatins, which sequester metal ions and initiate phytoremediation. Once the complex ion (phytochelatin plus metal ion) is absorbed through the root cell plasma membrane, a group of organic solute transporters actively transport phytochelatin-metal complexes into root cell vacuoles.5 For storage, plants move these metal complexes to aerial tissue, such as trichomes, leaf epidermal cell vacuoles, and mesophyll vacuoles.5 Altogether, because wetland vegetation is known to perform this intricate process of phytoremediation at its highest capacity, cattail were used to determine how effective this vegetation is in desorbing chemical pollutants with the assistance of chelating agents. It is common knowledge that wetland cattail perform phytoremediation; however, chelatin-assisted metal translocation has only recently been discovSPRING 2015
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ered.8 Although many plant species are known to remove toxins from soil matrix, chelation of toxic metal ions by chelating agents has become an area of increasing importance. The reason why this is important is complexing chelants seem to increase the soil to root translocation of available free elements for absorption. A common nontoxic chelate is Na2H2 EDTA, which is used as a food additive, water softener in products such as shampoos, and used in whole blood to prevent clotting. Chemically, Na2H2 EDTA is a multidentate (many-toothed) ligand, which can donate up to six pairs of electrons to its central binding metal.7 Na2H2 EDTA wraps itself around a metal cation such as Cu2+ forming a complex ligand [Cu(EDTA)]2-. EDTA is often used in hospital settings to remove heavy metals out of the bloodstream as it is known to sequester metallic cations such as calcium (Ca2+), which is a major contributing factor to patients exhibiting atherosclerosis.2 Our experiment proposed that if the chelating agent Na2H2 EDTA is added to a constructed wetland harboring southern cattail (Typha domingensis) and dissolved copper sulfate (CuSO4) at a 6-8 pH range, then Na2H2 EDTA will assist in the phytoremediation of Cu2+ by binding to Cu2+ and subsequently faciliating its translocation from the soil matrix to plant roots. Thus, the proposed results include a graph of copper concentration versus time, which will be constructed to show the progression of metal translocation in soil solution over the course of 3 weeks.
Methods and Materials
Reagents Na2H2 EDTA was purchased from Baylor Sciences Building, Baylor University, TX, USA. The analytical balance was purchased from Baylor Sciences Building, Baylor University, TX, USA. The plants were obtained from Waco Wetlands, TX, USA. Copper Sulfate was purchased from Baylor Sciences Building, Baylor University, TX, USA. Background Soil, Plant, and Heavy Metal Characterization Three large containers were used (Figure 1): the first (1) contained water hyacinth, Cu2+, and EDTA; the second (2) contained EDTA and Cu2+ serving as the control; the third (3) contained water hyacinth and Cu2+.
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Figure 1: (1) water hyacinth, Cu2+, and EDTA; (2) EDTA and Cu2+ serving as the control; (3) water hyacinth and Cu2+.
Each of the three containers were charged with wetland water (30 L, pH 7) and soil (20 kg). Containers were 60 cm by 60 cm by 80 cm. Water and soil were taken from Waco Wetlands, TX (31°32’N, 97°8’W). 15 large southern cattails (Typha domingensis) were gathered from wetlands at a uniform height of 30 to 40 cm high measured from the 30 L water line. 5 plants were partitioned into 3 containers with 5 replicates (pots) in each. The initial Cu2+ concentration (before Cu2+ or Na2H2EDTA was added) for tested containers was 0.00 mg/L. Plants were grown outdoors in Waco Wetlands with light intensity during the day time. No canopy or protection for plants was used. Temperature varied between 10o C and 25o C. Pots were not irrigated. Fox Farm Tiger Bloom fertilizer was added. Container 1 was charged with powder Na2H2 EDTA (2.011 g) and Cu2+ (2.018 g); Container 2 was charged with Na2H2 EDTA (2.001 g) and Cu2+ (2.012 g); Container 3 was charged with only Cu2+ (2.022 g). Heavy Metal Analysis Cu2+ concentrations for each container were measured once a week over the course of a three-week observation period. The concentration was determined using Hach Company DR/890 colorimeter. The Bicinchoninate (Hach Method #8506) procedure was followed using Cu2+ powder pillows. A reagent blank correction using DI water was performed. 10 mL samples obtained from containers 1, 2, and 3, were placed into DR/890 colorimeter cuvettes. The concentration of free copper was measured.
Results
The concentration of [Cu(EDTA)]2- was found to increase in basin 1 soil solution indicating that EDTA may not facilitate the process of phytoremediation of
copper by southern cattail (Figure 2). The concentration of Cu2+ continually increased in basin 1 (plant, Cu2+, EDTA). The concentration for basin 1 was found to be 1.02 mg/L, 1.36 mg/L and 1.56 mg/L for weeks 1, 2, and 3 respectively. The concentration of Cu2+ increased in basin 2 (Cu2+ and EDTA) but decreased during week 3. The concentration for basin 2 was found to be 0.79 mg/L, 1.65 mg/L and 1.35 mg/L for weeks 1, 2, and 3 respectively. Basin 3 (Plant and Cu2+) showed variation as it declined during week 2 and slightly increased during week 3. The concentration for basin 3 was found to be 0.40 mg/L, 0.12 mg/L, and 0.59 mg/L for weeks 1, 2, and 3 respectively.
Figure 2: Cu2+ concentration vs. time showing the increase of copper concentration over the course of 3 weeks. Basin 1 is green, Basin 2 is blue and Basin 3 is red.
Statistical Analysis The overall p-value was 0.02 indicating these results are not due to chance since the value is below 0.05. Due to the fact that our value is below 0.05, we rejected our null hypothesis, which stated that the addition of EDTA to our constructed wetland would have no effect on phytoremediation.
Discussion
The preliminary findings suggest that EDTA may not assist in the phytoremediation of heavy metals. Since the concentration of basin 1 containing the cattail plant, Cu2+ and EDTA continually increased over time, it might be plausible to conclude that EDTA does not enhance phytoremdiation but may hinder the process of heavy metal uptake. However, based on the results, the experiment proves to be a useful and viable way of determining the unknown concentration of copper in
plant soil solution because the DR/890 colorimeter was shown to be an effective instrument in evaluating the copper concentration signals. The experiment indicates this may be a useful way to evaluate the effectiveness of EDTA assisted phytoremediation. Based on the experimental results, this procedure may be a practical method for determining other concentrations of ionic species in biological ecosystems where water contamination is of the utmost importance. The experimental procedure presents an easy preparation of EDTA and copper sulfate solutions and avoids exceedingly dangerous reagents. Furthermore, the DR/890 served to be an efficacious way of determining an unknown concentration because the concentration vs. time plot proved to be useful in finding the change in copper concentration trends for each individual basin. Altogether, due to the experimental time-span, it may be prudent to conduct more tests to determine the efficacy of EDTA assisted phytoremediation. Although the results suggest EDTA may not enhace phytoremediation, there are several areas that may be investigated: First, it may be advisable to discard the use of Tiger Bloom fertilizer as this fertilizer may contain trace amounts of ionic species. Second, it may be prudent to place the cattail plants in a controlled (greenhouse) environment. Third, removal of the soil matrix from the containers may work to eliminate the intermolecular attractions that may occur between the soil and copper atoms. Although soil is necessary for cattail survival, removal of soil matrix may correlate to an increase in accuracy when testing for Cu2+ concentration. Sources of systematic error may include reduced or increased readings on the experimental equipment such as the DR/890 due to external environmental influences. Random error may be due to the unpredictable fluctuations in the readings on the analytical balance or the DR/890 resulting from the ability to accurately obtain representative samples of soil water from the plant basin containers. In the future, these errors should be avoided when performing analytical techniques and procedures for determination of unknowns as they can impact other calculations if they are not precise and accurate.
Acknowledgements
A special thanks to Marty Harvill, PhD and Baylor University for providing experimental instrumentation. SPRING 2015
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References
1. Baker, A.; McGrath, S.P.; Sidoli, C.M.; Reeves, R.D. The Possibility Of In Situ Heavy Metal Decontamination Of Polluted Soils Using Crops Of Metal-Accumulating Plants. Resour. Conserv. Recycle. 1994, 11, 41-49. 2. Beiergrohslein, E. The Use Of Surfactants In Removal Of Zinc, Lead And Cadmium From Contaminated Soils. Chemosphere. 1998, 12, 1-4. 3. Kumar, P. B. A. N.; Dushenkov, V.; Motto, H.; Raskin, I. Phytoextraction: The Use Of Plants To Remove Heavy Metals From Soils. Environ. Sci. Technol. 1995, 29, 1232-1238. 4. Manios, T.; Stentiford, E.; Millner, P; Removal Of Heavy Metals From A Metaliferous Water Solution By Typha Latifolia Plants And Sewage Sludge Compost. Chemosphere. 2003, 53, 487-494. 5. Mehes-Smith, M.; Nkongolo, K.; Cholewa, E. Coping Mechanisms of Plants to Metal Contaminated Soil, Environmental Change and Sustainability. Intech. 2013, 10, 5772-55124. 6. Tang, S.; Wilke, B.M. Brooks, R.R. Heavy-metal uptake by metaltolerant Elsholtzia haichowensis and Commelina communis from China. Commun. Soil Sci. Plant Anal. 2001, 32, 895-905. 7. Tro, N. Chemistry: A Molecular Approach, 3rd ed.; Pearson Education: Upper Saddle River (NJ), 2011. 8. Yeh, T. Y.; Pan, C. T. Effect of Chelating Agents on Copper, Zinc, and Lead Uptake by Sunflower, Chinese Cabbage, Cattail, and Reed for Different Organic Contents of Soils. J. Environ. Anal. Toxicol. 2012, 2, 1-4.
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Original Research
The Effects of Varying Burn Intensities on Plant Growth Jennifer Teague, John Bowersox, Kirk Reeves, and Marty Harvill, Ph.D. Department of Biology, Baylor University, Waco, Texas Abstract
In this study, the effects of a fire’s temperature on soil are examined, as well as the effect this has on the rate of secondary succession in the Lake Waco Wetlands. Controlled burns of varying fire intensity are set occasionally to regulate invasive species and maintain diversity. Six months ago, a controlled burn occurred. Fire temperatures varied based on wind intensity and ranged from 99 °C to 468 °C. Certain research showed that as fire intensity increases, plant growth decreases; though plants exposed to a low burn grow better than no burn. However, initial results showed that plants from the high burn soil grew significantly larger and stronger than plants growing in the control or low burn plots. High burn plants were taller, and on average had larger leaves, while flower and leaf count showed little difference between the plots. High Burn plants were also twice as heavy as low burn plants which fared the worst overall, though the low burn soil bore twice as many plants. Chemically speaking the high burn and low burn plots were very similar as both had a higher nutrient content than the control. Nitrogen was higher in the low plot compared to the high burn plot. This is due to the fact that the low burn soil did not reach the point of combustion for nitrogen. More research should be conducted on clay type soils as the results of this research design did not support the initial hypothesis or prior research on porous soil.
Introduction
Soil nutrients are one of the most important factors affecting plant growth. Available nutrients can affect plant size and the rate at which plants grow. The major nutrients that plants use to grow are nitrogen, potassium and phosphorus. Potassium plays a key role in metabolism of plants. Potassium acts as a regulatory agent that switches on or enhances enzyme activity. Enzymes are proteins that act as a catalyst in a biological system. Without the required level of potassium in the soil, plant growth would be severely stunted since metabolic rates would be drastically slowed. Phosphorus is a major building block of the cell. It acts as the backbone for DNA and a major substrate in cell membranes. Many cellular commands and movement of energy through the use of ATP are governed by this one element. Without adequate phosphorus, cells cannot grow or perform normal metabolic activities. Nitrogen is another major element used in DNA and is one of the major components of proteins and enzymes. When nitrogen is extremely low, it is hard for the cell to do any work or even grow. When a fire occurs, nitrogen is
volatized and potassium is returned to the soil from in the form of ash. Through ash, the nutrients are reincorporated rapidly and can even improve the quality of the soil. However, when a fire surpasses 275 °C nitrogen begins to burn off. This can damage the soil and scar it, killing off any nitrogen fixing bacteria and resulting in an overall net loss of nitrogen. This can make it hard for plants to return, and sometimes plants may not regrow for many years.1 However if a fire’s temperature is below the threshold for combustion, then net nitrogen levels should see an overall increase. Phosphorus and potassium on the other hand do not burn off easily. The only way for potassium or phosphorus to be lost is though runoff or through wind picking up ash and carrying it away.2,3 The physical properties of soil can also be altered. As organic matter begins to burn, a layer of matter impermeable to water begins to form in the soil. This is created from the loam and plant litter on the surface of the soil. One study noted that as fire temperature increased, the strength and depth of the layer SPRING 2015
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of impermeability increased. Clay based soils such as the ones found in the Waco Wetlands are almost immune to the soil degradation effect of wild fires, whereas porous or rocky soils are easily damaged and can be ruined.2 Microorganisms have a tendency to die off or become infertile as fire temperature increases. As the organic matter burns off, the food source for microorganisms is lost. In bacteria that survive the fire, proteins can be denatured, slowing metabolic processes and the rate at which microorganisms can recolonize the soil. Water loss from the soil is also a factor affecting microorganisms. Water is used by bacteria and protists as a medium for moving and collecting nutrients through osmosis. Nitrogen-fixing bacteria are most affected by increases in temperature. This can explain why soil is slow to recover nitrogen after a hot fire. This also explains why soil near the surface during a hot fire can become almost devoid of nitrogen: all nitrogen sources have been depleted.2 Because of this, it could take months to years before plants can recolonize an area after a high intensity fire. There are a multitude of reasons why a wild fire may occur. In tropical nations, many farmers practice slash and burn agricultural techniques in place of traditional fertilizers. Slash and burn works by clearing the plant matter from a small section of a forest and setting it on fire to replenish the soil’s nutrients. Studies have shown that this technique, if properly preformed, can replace fertilizer for up to one year. Fires can also be started accidently by humans or by natural means such as lightning. For this to occur, large amounts of dry biomass, such as grasses or pine needles, must have accumulated. This occurs in many ecosystems as a natural way of encouraging plant growth. For example, the California Red Wood only germinates after a fire. This ensures that developing plants have optimal growing conditions. Finally, humans use fires to control the influx of invasive species and to promote biodiversity. By performing controlled burns, humans can maintain an ecosystem longer and more easily.2
Methods and Materials
Three 19 liter buckets were filled with soil from the Waco Wetlands: one unburned sample, one high intensity burn sample of 468 °C, and one low intensity burn sample of 99 °C. The burn plots were sectioned off by metal poles according to fire intensity, and were located about 100 meters apart. The organic layer of soil was removed with a shovel, and top soil, the layer 14
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of soil affected most by a burn, was collected. Established plants, such as grasses and weeds, were uprooted and removed by hand from the soil in an effort to limit the variables affecting new plant growth. The soil was transferred from the Lake Waco Wetlands to the Baylor Science Building so that the project could be completed in a controlled environment. The soil from each bucket was transferred into three 61 cm by 91 cm clear plastic containers and broken up for easier handling and planting. The plastic containers were placed side by side on a counter, half a meter below direct fluorescent lighting. The fluorescent light stayed on throughout the experiment. Two hundred Wisconsin Fast Plants, Brassica rapa, were ordered from the Carolina Biological Supply Company. Brassica are members of the crucifer family of plants, closely related to cabbage, turnips, broccoli and other cruciferous vegetables. Professor Paul H. Williams has bred fast plants for over 30 years at the University of Wisconsin, and the plants require little more than light, water, and fertilizer to thrive. The plants flower in 12 to 14 days and complete their life cycle in 35-40 days. Under ideal growing conditions recommended by the Wisconsin Fast Plants Program, plants would be kept under an intense source of coolwhite fluorescent light 24 hours a day throughout their life cycle. They would be planted using the recommended kit with potting mix, planting units, fertilizer pellets, a water reservoir, and diamond wicks and a water mat to conduct water from the water reservoir to the plants. In order to allocate monetary resources efficiently, maintain the integrity of the wetland soil, and limit variables, the recommended set up was rejected when conducting this experiment.4 Out of the 200 Brassica rapa ordered, 67 seeds were equally spaced in each container. Two to three seeds were placed in holes spaced roughly 5 cm apart in a 5 by 6 hole grid spanning each container. The holes were made by hand, and were roughly 3 cm deep. All holes were covered with loose soil, and then each container of plants was watered with 1 L of water using a 1000 mL beaker. The subsequent two times the plants were watered, they received 750 mL of water and the rest of the time they received 500 mL of water. Plants were watered three times a week every Monday, Wednesday, and Friday. Every time the plants were watered, data on plant growth was collected. Each measuring period, 10 plants were selected at random from each container and measured for their height, leaf span, leaf
count, and flower count. Height and leaf span were taken using a standard ruler. Plants were stretched out straight, and height was measured from where the plant emerged from the soil to the highest part of the plant. Leaf span was taken measuring across horizontally from the widest part of the plant. Buds, blooming flowers, and dying flowers were all counted and placed under the measurement of flower count for each plant. Leaf count was simply the number of leaves per plant, including the cotyledons. When plants sprouted, four were chosen from each plot to be tested for mean spectral reflectance. The four chosen were close to the fluorescent light and had a slight space on all sides so as not to have any interference from other plants. Every week pictures were taken of these 12 plants using an infrared Nikon camera. The pictures were then uploaded into ImageJ, a Java image processing program, and analyzed to measure the mean spectral reflectance, near infrared light, red light, and green light reflected. To measure these, a leaf of the plant from the picture was cropped out and analyzed using a histogram. The mean values were then taken from each graph of the different reflected light ranges. The mean spectral reflectance was then found by dividing the near infrared light reflected by the red light absorbed. Soil samples were also taken weekly and analyzed for phosphorus and ammonia nitrogen content using a LaMotte soil sampling kit. Using a spatula, soil was removed from the middle of the containers. About 1 cm of soil was placed into a small LaMotte test kit vial, filled the rest of the way with water, and shaken to create the soil extract. For ammonia nitrogen testing, four drops of soil extract were taken and placed in a small dish combined with one drop of ammonia nitrogen test solution. This was mixed and then left to settle for five minutes. The color was then compared with the LaMotte test kit chart for the level of ammonia nitrogen in the soil. For phosphorous testing, soil extract was added to the test vial up to the fill line, and 4 drops of the phosphorus test solution were added. Then, the vial was capped and shaken. The vial was uncapped, a phosphorus test tablet was added, and then the vial was recapped and shaken. The color was compared with the LaMotte test kit chart to determine the level of phosphorus in the soil.
Results
At the end of the experiment, there were 24 plants in the control soil, 51 in the low burn soil, and 28 in the
high burn soil. After drying each group of plants, the dry masses were 1.1g, 1.0g, and 1.2g respectively. According to this, the dry masses per plant were .0458g for the control, .0196g for the low burn, and .0429g for the high burn. The mean spectral reflectance (MSR) is found using a ratio of reflected near-infrared light values to absorbed red light values. Higher values indicate plants with higher vitality. The amount of near infrared light a plant reflects, show a similar trend among all three groups (Figure 1). Percent reflectance started high when the plants were using seed nutrients instead of soil nutrients, and then drastically decreased in the following weeks with a slight increase in all three plots in the last week. While there was no statistical difference between leaf and flower count, leaf width and plant height showed significant difference between soil groups. For the final average height, the control group measured 15.01cm, the low burn 11.95cm, and the high burn 18.31cm (Figure 2). The high burn plot plants grew taller on average than both the low burn and the control. The low burn grew the least and had the widest range of height in each measurement period. In the final average leaf width, the control group measured 6.14cm, the low burn 4.9cm, and the high burn 7.57cm. The leaf width of plants in the high burn-intensity soil grew exponentially, while both the leaf widths of plants in the control and low-intensity burn grew linearly over time (Figure 3). The high intensity burn plants had larger leaf widths than any other group. The soil samples were inconclusive in high and low burned soils, though they showed increased nutrients over time, with a decrease in nutrients during the last week. In the soil samples, the phosphorus levels started at 75lb/acre for the control and the high burn soil, and 100lb/acre for the low burn soil. The low burn and high burn soil increased to 150lb/acre, and the control increased to 100lb/acre. At the end, however, the low burn and high burn decreased significantly, with the low burn becoming 50lb/acre and the high burn becoming 25lb/acre. In the ammonia nitrogen levels, all three soil groups started at a “Very Low” reading, and all three groups also increased to a “Low” reading over the course of the experiment. However, at the end, the control soil decreased to a “Very Low” reading. SPRING 2015
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Figure 1. The x-axis shows the date the measurements were taken, and the y-axis shows the % reflectance of the plants on the given day. The closer to 1, the healthier the plant is subjectively.
Figure 2. The x-axis is the date the measurements were taken, while the y-axis is the height in cm.
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Figure 3. The x-axis is the date the measurements were taken, and the y-axis is the distance in cm from leaf tip to tip.
Discussion
In the experiment, plant height, leaf span, and dry mass indicated that the high burn-intensity plants grew more than either the control or the low burn-intensity plants. According to the number of plants in each soil sample, the low-intensity burn had around twice as many plants in comparison to both the control and high burn. However, when all of the plants were dried and weighed, the dry mass per plant was higher in the high burn than in either the low burn or control soils. This did not support the hypothesis that low burn-intensity plants would grow the best; thus, the hypothesis was rejected. Another factor that showed how the Wisconsin Fast Plants grew was the mean spectral reflectance, or MSR. Healthier vegetation tends to have bigger cells with more water at the cell wall/membrane interface which reflects a lot of the incoming near infrared. Because healthier cells also have more chlorophyll, more red wavelengths are absorbed. The simple ratio is bigger for healthier plants and smaller for less healthy plants, so plants with a higher MSR are healthier.5 MSR is measured by taking a picture of a plant with an infrared camera, putting the picture in a photo editing program, and plotting the area of a leaf into a program called ImageJ. Using this program gives the values of reflectance for red, green, and near-infrared light. The MSR is calculated by dividing the reflected near-infrared value by the absorbed red light value. In the experiment, the measured MSR values started high when the plants were using seed nutrients instead of soil
nutrients, and then drastically decreased in the following weeks with a slight increase in all three plots in the last week. This shows that the plants had a difficult time adjusting to the soil. The MSR shows that the conditions the plants were in did not allow the plants to grow to their full potential, which is unfavorable, but allowed the experiment to be kept under control with few variables. Also, according to leaf width, the high burn-intensity soil showed a growth that occurred exponentially, while both the control and low-intensity burn were linear growth. The high intensity burn plants had larger leaf widths than any other group. The same is true for comparing the heights of each soil group. The high burn plants showed an exponential growth rate while the control and low burns showed a linear growth. According to plant height, the high burn plants grew the most. On the other hand, flower count and leaf count had no statistical difference between soil groups. The number of plants was also not an accurate measure of plant growth, since after taking the dry weight of each plant group, it was determined that the average weight per plant was higher in the high burn plants than the low burn plants, even though the low burn soil had twice as many plants as the high burn soil. Also, the mean spectral reflectance shows that there was a decline in the growth rate for the plants. The Wisconsin Fast Plants also have ideal growing conditions that were not met. These conditions were SPRING 2015
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not used because they were specially made to optimize growth for the Wisconsin Fast Plants, and would have skewed the experimental results by optimizing growth and changing the soil contents, rather than allowing the soil to be the only variable. This means that if the plants were put in optimal conditions, the mean spectral reflectance would have increased, since the plants could grow to their best ability. The Brassica rapa were not planted under ideal conditions, and thus did not grow as large as possible. First, the directions for planting Wisconsin Fast Plants were to plant with fertilizer and constant watering. To keep the amount of variables low, fertilizer was not used and a fixed watering schedule was used. Another condition that could have altered data was that the plants were delicate and measuring them may have affected their growth. Also, some other plants that were in the soil when it was collected regrew, along with the Fast Plants. These other plants may have caused some of the Fast Plants to be uprooted and could have competed with some of the Wisconsin Fast Plants for nutrients, causing them to grow less. One last possible source of error is that during the experiment, the plants began to wilt around the one week- two week mark. To prevent wilting, the amount of water given to each soil group was decreased from 750mL to 500mL. Another variable that explains how the soil affected the plants is soil nutrients. In the experiment, ammonia nitrogen and phosphorus were tested. Ammonia nitrogen is a common way of transferring nitrogen to plants; nitrogen is necessary for making enzymes and aiding in metabolic processes, while phosphorus aids in sugar formations and also encourages flower blooming and aids in root growth. In the experiment, the levels of ammonia nitrogen increased in each soil group, although it only slightly increased over time, from a “Very Low” reading to a “Low” reading in the soil. Nitrogen levels were higher overall in the burn plots than the control plot. Phosphorus levels increased greatly each week in each soil type, but then a decrease in the level of phosphorus occurred in the last week of data collection. Phosphorous levels were consistently higher in both of the burn plots compared to the control plot. According to this data, burns can actually be beneficial to plant growth. Given time for the soil to stabilize after a burn, the higher the intensity of the burn, the better the plants will grow back after, as shown in a comparison of the burned soil groups versus the control soil. While a controlled burn is ben18
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eficial to a point, techniques such as slash-and-burn, when used improperly, actually harm the environment by not giving the soil enough time to recover for plant growth to occur. Slash and burn is only beneficial when done properly, when diverse plants are reintroduced to the soil as opposed to one crop. This is why controlled burns are useful for increasing plant diversity: they promote plant growth, increase soil nutrients, and clear the land to make way for new plants.2
Acknowledgements
We would like to thank Nora Schell, Lake Waco Wetlands Coordinator; Dr. Joseph White; Dr. Robert Doyle; Baoqing Ding, and the Baylor Biology Department for providing instruction and resources.
References
1. Certini, G. Effects of Fire on Properties of Forest Soils: A Review. Oecologia. 2005, 143, 1-10. 2. DeBano, L. F. The Effect of Fire on Soil Properties. USDA Forest Service Rocky Mountain Research Station. SoLo. http://goo.gl/MaHeLs (accessed Apr 28, 2014). 3. Kennard, D.K.; Gholz, H.L. Effects of High- and Low-intensity Fires on Soil Properties and Plant Growth in a Bolivian Dry Forest. Plant and Soil. 2001, 234, 119-129. 4. Lauffer, H. B.; Lauffer, D.; Williams, P. Wisconsin Fast Plants®. Swarming Technology. www.fastplants.org (accessed Apr 28, 2014). 5. Sims, D.A.; Gamon, J.A. Relationships between leaf pigment content and spectral reflectance across a wide range of species, leaf structures and developmental stages. Remote Sens. Environ. 2002, 81, 337-354.
Original Research
Studies of Synthetic Hydroxyheme and Heme Oxygenase
Regina Martinez, Tara Clover, M.S., and Patrick Farmer, Ph.D. Department of Chemistry and Biochemistry, Baylor University, Waco, Texas Abstract
Heme Oxygenase (HO) is a membrane-bound enzyme composed of 288 amino acid residues. In mammalian organisms, it is responsible for catalyzing the conversion of heme to biliverdin, free iron, and carbon monoxide in the presence of oxygen, NADPH, and cytochrome P450 reductase. The conversion of heme to biliverdin involves three consecutive oxygenations in which heme is converted sequentially into α-meso-hydroxyheme and verdoheme, and ultimately into biliverdin. The first intermediate, α-mesohydroxyheme, is very reactive in the presence of air. Therefore, less reactive octaethylporphyrin was used to provide a stable synthetic model of this intermediate. In this project, the iron(III) 5-oxyoctaethylporphyrin dimer was synthesized by a three step process. In the first reaction, iron(III) octaethylporphyrin (OEP) was reacted with pyridine, hydrazine, and acetic acid, yielding dipyridine iron(II)OEP. In the second reaction, meso oxygenation of the dipyridine iron(II)OEP was effected using a 1% H2O2 solution, and the meso-oxygenated product was protected by reaction with benzoyl chloride which yields the air stable iron(III)5-benzoyloxyoctaethyl porphyrin. The iron(III) 5-oxyoctaethylporphyrin dimer is produced by benzoyl deprotection using sodium methoxide. In acidic conditions, the dimer will dissociate and will react with oxygen from air to form octaethyl verdoheme. The products of these reactions were characterized by mass spectrometry and UV-Vis spectroscopy.
Introduction
Heme Oxygenase (HO) is a membrane bound stress-induced enzyme composed of 288 residues. Heme acts as both its cofactor and substrate; degraded heme products biliverdin an bilirubin result from its action.4 In biological systems, HO has been implicated in the regulation of growth and survival of various neoplastic cells, such as those responsible for chronic myeloid leukemia.6 Furthermore, regulation of heme metabolism and the control of byproduct production such as bilirubin, are essential to developing safe treatments for severe neonatal jaundice and hemorrhaging, as existing treatments such as phototherapy and blood transfusions can be harmful to the baby.1 In the conversion of heme to biliverdin, HO requires successive equivalents of oxygen and NADPH-cytrochrome p450 reductase, also generating free iron and carbon monoxide. This process comprises three consecutive oxygenations, sequentially generating α-mesohydroxyheme and verdoheme as intermediates, and finally, biliverdin as product. The first intermediate, α-mesohydroxyheme, is very reactive species
and difficult to isolate or follow in normal chemical reactivity. In this project, a dimeric [FeIII(oxyoctaethylporphyrin)]2 is utilized as a more stable synthetic model of this intermediate in order to study its reactivity.5 The stable dimer breaks apart to the more reactive monomer in acidic conditions.8 Our group is particularly interested in the reaction of the monomer with HNO, an analogue of oxygen, to determine some of the details of the mechanism of verdoheme production. In this project, the Fe(III) 5-oxyoctaethylporphyrin dimer is synthesized by three reactions, Scheme 1.2,7 In addition, kinetic studies will be carried out using a truncated version of the enzyme, which requires HO expression and purification.
Methods and Materials
Synthesis of Dipyridine Iron (III) OEP Iron(III) octaethylporphyrin (OEP) (151.7mg, 0.16 mmol) and a stir bar were added to a 250 mL Schlenk flask (equipped with a septa and copper wire) and were SPRING 2015
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degassed. Degassed pyridine (20ml) was added to the Schlenk flask under nitrogen via cannula. The flask was lowered into an oil bath and was allowed to heat at 50°C. Once this temperature was reached, hydrazine (0.5ml, 0.01 mol) was added to the solution and was stirred for 5 min. The flask was then taken out of the oil bath and was lowered into an ice bath to reach a temperature of 0°C. Acetic acid (0.75ml) was then added to the solution and was allowed to stir for 2 min. Water (22ml) was then added to the solution and was stirred for 1 hour at 0°C. A red-purple precipitate formed and was filtered off by vacuum filtration (120.3 mg, 79.8%). Experimental λ (pyridine): 407, 508, 517, 545 (nm). Synthesis of Iron(III) 5-benzoylOEP A meso oxygenation of the dipyridine iron(II)OEP was carried out by reacting it with a 1% H2O2 solution. Dipyridine iron(II)OEP (120.3 mg, 0.16 mmol) and a stir bar were added to a 250 mL Schlenk flask (with copper wire and septa) and were degassed. Degassed pyridine was added to the flask via cannula. The flask was then lowered into an oil bath and was heated to 60°C. A degassed 1% H2O2 solution was added to the flask via syringe and stirred at that temperature for 15 minutes. A color change from red to olive green was observed. Benzoyl chloride (2.8 mL, 24.16 mmol) was then added to the flask and was continued to stir at room temperature for 30 minutes. A color change from olive green to reddish brown was observed. Solvent was removed under reduced pressure. The residue was dissolved in 50 mL of CHCl3. The solution was washed with saturated NaHCO3 solution (3x100 mL) and was also washed with distilled water (3x100 mL). The organic phase was dried over NaSO4. It was then filtered and the solvent was removed by rotary evaporation. The residue was eluted in 1% MeOH/CHCl3 over a silica gel column. λ (CHCl3): 383, 505, 533, 638 nm; MS/ ESI (m/z): 708. Synthesis of Iron(III) 5-oxyoctaethyl porphryin dimer The iron(III) 5-oxyoctaethylporphyrin dimer is produced by stirring Iron(III) 5-BenzoylOEP (40 mg/0.033 mmol) in 1M sodium methoxide in MeOH for 5 hr in N2. Water was added to the solution and the flask was then opened to air. The flask was placed into the refrigerator overnight allowing for a precipitate to form. The dark red precipitate was collected by vacuum filtration. The product was purified by column chromatography using silica and eluted first using 20
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Scheme 1: Synthesis of Iron (III) 5-oxyoctaehthylporphyrin dimer from three consecutive reactions of OEP. A. 1) py, N2H2, 5 min 2) CH3COOH, H2O, 0°C, 1hr B. 1) 1% H2O2, py, N2 (g), 15 min. 60°C 2)C7H3ClO, N2 (g), 30 min, 25°C C. 1) py, 1 M NaOCH3, MeOH, N2 (g), 25°C, 5 hr 2) H2O (crystal formation) 3) Silica column in CHCl3/1%MeOH
CHCl3. λ (CHCl3): 390, 490, 530, 670 nm; MS/ESI (m/z): 1206 (Figure 1). Transformation and Expression of Heme Oxygenase 3,9,10 Plates with fresh colonies of transformed E. Coli DH5αF’ cells containing the Δ233-HO-1 gene were used to prepare a 5 mL inoculum in LB-AMP induction media. Seven 1 L cultures were inoculated from the overnight cultures, grown 37°C to an OD600 of 0.3 – 0.5 and were induced with 1 mL of 1 mM IPTG. The cells were grown between 15-18 hrs. The cells were lysed in a 50 mM TRIS 2 mM EDTA buffer containing 1 mM PMSF by a French press. A solution of 35 µL/mL of 10 % polyethyleneimine was added to the lysate and was placed on ice for 25 min. The lysate was brought to 40% ammonium sulfate saturation with gentle stirring for 25 min. It was centrifuged at 15,000 RPM for 25 min. The pelleted material was discarded and the lysate was then brought to 70% ammonium sulfate saturation with gentle stirring for 30 min. This was followed by centrifugation at 10,000 RPM for 15 min. The liquid was discarded and the green pelleted material was resuspended and dialyzed 3 x 4 hours each in the 50 mM TRIS 2 mM EDTA buffer. The precipitate that formed during dialysis was removed using a Nalgene vacuum filtration system containing a 0.2 μm PES membrane. The protein was then filtered on a Sephadex G-75 gel filtration column using pH 7.4 20 mM phosphate buffer. The fractions were analyzed by UV-Vis and SDSpage. UV-Vis λmax=280 nm.
Results
Mass spectrometry was used to confirm the formation of the dimer (Figure 1). After synthesis, the dimer was placed under acidic conditions to observe its decay to verdoheme at 676 nm (Figure 2).
disease. In theory, one could speed up the process of heme decomposition or slow it down however needed. Also, by understanding this mechanism, one can contribute to future research on childhood blood disorders and cancer as HO has been found to play a role in the propagation and survival of chronic and acute myeloid leukemia. This research will be a foundation for future research in a related topic.
References
Figure 1: Mass Spec Confirmation, m/z of 1206 represents the dimer
Figure 2: Dimer decay into verdoheme upon solvation with chloroform with 2% of pH 5.5 0.1M Tris HCl buffer
Discussion
The appearance of the mass spec peak at m/z of 1206 and the growth of the expected verdoheme peak at 676 nm, upon the addition of acid to the product, confirmed the formation of the Iron(III) 5-oxyoctaethyl porphryin dimer. Further studies will be carried out with the newly synthesized dimer to better understand the mechanism of heme decomposition by the enzyme heme oxygenase (HO). Given the serious, though rare, complications of phototherapy and blood transfusions involved with conditions such as severe neonatal jaundice, exploring the mechanisms behind heme degradation can help develop an alternative treatment to this
1. Abraham, N.; Alam, J.; Nath, K. (Eds.) Heme Oxygenase in Biology and Medicine. Kluwer Academin/Plenum Publishers. New York, NY, 2002, pp. 3-11. 2. Bonnett, R.; Dimsdale, M.J. J. Chem. Soc., Perkin Trans. 1, 1972, 2540-2548 3. Lad, L.; Schuller, D.J.; Shimizu, H.; Friedman, J.; Li, H.; de Montellano, P.R.O.; Poulos, T. L. Comparison of the heme-free and-bound crystal structures of human heme oxygenase-1. J. Biol. Chem. 2003, 278, 7834-7843. 4. Maines, M. Heme oxygenase: function, multiplicity, regulatory mechanisms, and clinical applications. FASEB J. 1988, 10, 2557-2568. 5. Masuoka, N.; Itano, H. Radical intermediates in the oxidation of octaethylheme to octaethylverdoheme. Biochemistry. 1987, 26, 3672 6. Mayerhofer, M. et al. Identification of Heme Oxygenase-1 As a Novel BCR/ABL-Dependent Survival Factor in Chronic Myeloid Leukemia. Cancer Res. 2004, 64, 3148-3154. 7. Morishima, I.; Fujii, H.; Shiro, Y.; Sano, S. Studies on the Iron (II) meso-Oxyporphyrin. pi.-Neutral Radical as a Reaction Intermediate in Heme Catabolism. Inorg. Chem. 1995, 34, 1528-1535. 8. Rath, S.P.; Olmstead, M.M.; Balch, A. L. Reactions of meso-Hydroxyhemes with Carbon Monoxide and Reducing Agents in Search of the Elusive Species Responsible for the g= 2.006 Resonance of Carbon Monoxide-Treated Heme Oxygenase. Isolation of Diamagnetic Iron (II) Complexes of Octaethyl-m eso-hydroxyporphyrin. Inorg. Chem. 2004, 43, 6357-6365. 9. Schuller, D.J.; Wilks, A.; de Montellano, P.R.O.; Poulos, T.L. Crystal structure of human heme oxygenase-1. Nat. Struct. Mol. Biol. 1999, 6, 860-867. 10. Schuller, D.J.; Zhu, W.; Stojiljkovic, I.; Wilks, A.; Poulos, T.L. Crystal structure of heme oxygenase from the gram-negative pathogen Neisseria meningitidis and a comparison with mammalian heme oxygenase-1. Biochemistry-US. 2001, 40, 11552-11558.
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Review Article
The Path to Vascular Dementia via Autoimmunity: A Review
David Thien Le and Michael Scullin, Ph.D. Department of Psychology and Neuroscience, Baylor University, Waco, Texas Abstract
Research into vascular dementia (VaD) has made milestones in terms of diagnostics and risk factors in recent years specifically in regards to risk factors that are cardiovascular in nature. The obvious correlation between cardiovascular diseases and VaD is seen through the known pathology of the diseases. What is not highlighted is other possible diseases that should be of concern towards vascular dementia either directly or indirectly. The topic of interest for this study is the implications that autoimmune diseases, specifically Systemic Lupus Erythematosus (SLE), have on VaD. A minimal amount of studies were found relating SLE and other autoimmunity diseases to VaD either through cardiovascular conditions or directly to VaD. These articles, dating back to 1992 onward, were analyzed for relevance to the topic of autoimmunity affecting the onset of VaD. It is evident that there is an underlying connection between many cases of VaD and autoimmune diseases, specifically with autoimmune severity based in large part to SLE studies. With the prevalence of these diseases across a spectrum of ages, dementia and VaD in particular is a concern not just for those suffering cardiovascular failure due to aging, but also for younger populations that suffer autoimmune diseases. This review will provide an overview of VaD, its relation to cardiovascular disease, the influence of autoimmune disease on VaD through various studies conducted, future concerns and directions on this topic.
Introduction
Since at least the 19th century, research has been conducted on the effect of vascular disease on cognition (Figure 1). In the present day, VaD is defined by cognitive loss due to various brain lesions from cerebrovascular complications and pathology. VaD is the second most prevalent form of dementia in the United States, and is a large issue especially amongst the elderly population where cognitive impairment is common. VaD is a broad term that encompasses vascular cognitive impairment (VCI) of reasoning, planning, judgment, memory, and other similar processes of the brain. This impairment originates with impaired blood flow causing brain damage, usually in the form of a stroke. The severity of stroke and where it occurs in the brain are influential factors for the onset and extent of VaD in the victim’s future. Other causes involved in vascular dementia involve the compromise of healthy cerebrovascular circulation that leads to deprivation of blood to the brain.10 As such, factors that play a role in this disease include high blood pressure and cardiovascular disease. 22
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The etiology of VaD can be very vague due to the complex cerebrovascular pathology of the syndrome, and as such, scientific literature also discusses VaD in many terms including two very common ones known as, ischemic vascular dementia (IVD) and subcortical vascular dementia (SVD). IVD refers to the lack of blood to tissues resulting in a lack of oxygen and blood sugar to brain. The hypoperfusion resulting from this condition will eventually lead to the victim experiencing stroke, a major cause of brain damage. SVD is similar to IVD, but refers more to the subcortical areas of the brain developing lesions of hypoperfusion due to ischemia (Figure 2). It must also be noted, that a third less common term for VaD is a combination of the above terminologies into one: subcortical ischemic vascular dementia (SIVD).12 With such varying terminology as discussed in the previous statements, historically VaD has been somewhat of an overarching term for cognitive impairment of any severity caused by ischemic cerebrovascular disease. Along with this fact, VaD’s ambiguity
Figure 1: A more in-depth historical aspect of VaD6 (Figure obtained with permission from the National Institutes of Health Public Domain)
has given way to multiple forms of diagnostic systems. The most popular diagnostic methodologies for VaD are the World Health Organization’s (WHO) International Classification of Diseases (ICD), American Psychiatric Association’s Diagnostic and Statistical Manual (DSM) , the Alzheimer’s Disease Diagnostic and Treatment Centers (ADDTC) criteria, and the National Institute of Neurological Disorders and Stroke with the Association Internationale pour la Recharché et l’Enseignement en Neurosciences (NINDS-AIRENS) criteria. Although there is some overlap between the various diagnostic protocols (Figure 3), only a few patients out of the many diagnosed with VaD using one of the above criteria factors, have overlapping criteria from another diagnostic method.12 Another related concern is the pressing matter of historically continuous overlap between vascular dementia and Alzheimer’s disease in terms of diagnoses, research study, and classification. This further complicates the actual understanding of vascular dementia as a disease, specifically in relation to risk factors such as hypertension, peripheral arterial disorders, diabetes mellitus, and smoking.23 With the above statements in mind, current epidemiological
Figure 2: MRI scan of SVD, with white matter lesions near the center showing decreased cerebral blood flow.14 (Figure obtained with permission from the National Institutes of Health Public Domain)
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Figure 3: A comparative chart for the four of the diagnostic protocols for VaD.12 (Reprinted with permission from John Wiley and Sons)
studies show that VaD is the second most common type of dementia globally. North America as a continent follows this global trend through its 2:1 ratio of Alzheimer’s disease (AD), which is the most prevalent form of dementia, to VaD. On the other hand, studies in Japan have proven further prevalence of VaD in 1:1 ratios of AD to VaD. 12 Further studies in Asia have shown how much a concern this above-average prevalence is via the effects of VaD in regards to early onset dementia.11 In general, studies in the epidemiology of VaD have shed some light on the presence of risk factors that increase the prevalence in VaD in the global population which include old age, hypertension, diabetes, metabolic syndrome, and stroke. These risk factors amongst society highlight the public health threat that VaD can pose now and in the near future.12 VaD results in numerous cognitive impairments in the neuropsychological domains of learning and memory, executive functioning, language, visual perception, and psychomotor capabilities. Memory impairment is known to be one of the earliest symptoms of VaD, 24
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and is a foundational guideline for diagnostics. Studies have shown that episodic memory and sporadic retrieval and encoding problems are common in the cognitive failure of VaD patients. Neuroimaging studies have pinpointed the believed source of these memory impairments to the prefrontal metabolic processing. Stroke-induced cognitive impairment has been known to affect this function of the human brain. Though of lesser importance for VaD diagnosing protocol, executive functioning decline has historically been very noticeable in the populace with VaD. Executive function refers to the process of conceptualization and its transition to human reaction through behavior. Various studies conducted have shown dysfunction in abstract thinking, logical thinking, generation, sequencing, inhibition, and mental flexibility. All of these symptoms are evidence of cognitive impairment of executive functional processing of patients.12 Language skills, such as understanding, repetition, and naming, are progressively detrimentally affected, thereby resulting in an increased frequency
of errors in semantics and auditory cognition. While auditory perception declines, so does visual perception and cognition. This is seen through the impairment of acquisition and perceptive abilities such as shape discrimination, object perception, facial recognition, and spatial localization. The source of these conditions is believed to be due to damage to the frontal lobe of the brain from cerebrovascular complications. In regards to physical activity, VaD patients suffer a disproportionate decline in psychomotor function as the connection between information processing and motor responses decays. Neuropathological studies has shown that subcortical white matter is vital to these functions, and neuroimaging of VaD patients has shown these areas of the brain to be damaged.12
Cerebrovascular-Autoimmune Pathology
A major component of the onset of VaD is the condition of the cerebral blood vessels. This component of the circulatory system of the body has the vital role of providing oxygenated blood and nutrients to the brain.10 In order to maintain important functions such as synaptic activity, the brain sets itself in the position to be a large center for energy usage in the human physiological system. The circle of Willis is an interconnected network of cerebral arteries which serves as prime example of the unique “outside in” vascularization structure of the brain that is vital to brain function. Also, control mechanisms, nutrient dependence, and immunological functioning of the neurovascular unit of the brain are extremely diverse and complex involving a variety of neural cells that manage blood
flow, brain development, metabolism, homeostasis, and immune response.10 Cerebrovascular pathology has a broad spectrum of pathways towards cognitive impairment involving VaD, as seen through changes of small vessels that impact global cerebral perfusion. Brain damage from reduced cerebral perfusion due cardiac complications or hypotension is common. Also chronic ischemia could result from enlargement or blockage of carotid arteries, which is a more indirect pathology of VaD. Stroke patients have a doubled risk for dementia, a finding that is not limited to older adults, but also extends to young adults. Reduced cerebral flood flow over time are a cause of ischemic stroke. Multiple infarcts could impair cognition to a large extent, and is more likely to occur with the vascular burden present in the cerebrovascular system.10 Figure 4 below serves a small guide to some of the possible connections between dementia and cerebrovascular pathology. Only a part of these pathologies will be covered, but worth noting is the connection between inflammation and dementia. The greatest threat to cognitive impairment is from changes in small vessels in the white matter of the brain. Research into small blood vessel diseases has shown that lacunes, one of the most common brain lesions, have a high correlation with a number of VaD patients. In the cerebral white matter, lacunes cause cavitating infarcts, which is usually paired with either other lacune or other small vessel disease-induced infarcts, increasing the vascular cognitive decline of the victim.15 Small vessel diseases like arteriosclerosis
Figure 4. A diagram depicting a small scope of the mechanistic pathology of VaD (hypoxia) and AD.6 H1F1α- hypoxia-inducible factor 1-alpha, eNOS/iNOS- endothelial/inducible nitric oxide synthase, Aβ- amyloid beta plaques, ROS- reactive oxygen species, AD- Alzheimer’s disease. (Figure obtained with permission from the National Institutes of Health Public Domain)
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cause large plaque buildups, accumulation of hyaline substances, and fibrotic changes. The white matter damage from these various lesions involves more infarcts, cell death, demyelination of axons, and axon function failure. Over time, the cognitive impairment from these abnormalities will increase as the lesions continue to appear in the brain. Another well-known cause of vascular cognitive impairment (VCI) is cerebral amyloid angiopathy (CAA) which involves the deposits of Aβ plaques. Cardiovascular disease has been known to play a role in this condition especially in the older population.10 The cerebrovascular pathology of VaD is understood mostly in terms of Figure 4, and specifically through inflammation where lupus and autoimmunity conditions can play a role in the progression of this disease. Lupus is an autoimmune disease that causes the immune system to create autoantibodies that damage the human body via organs, skins, and joints. Symptoms of this destructive activity include pain and inflammation. Lupus is a disease that is focused specifically on an overactive immune system. As a disease that damages tissues, lupus is a likely threat to the brain, where it could induce VaD in victims. A common subtype of lupus is SLE, which is an excellent representative for auto-immune diseases in regards to their pathophysiology. Epidemiological studies of cardiovascular disease in SLE have shown connections between patients who suffered from CVD and SLE. A study in Sweden found that immune related diseases such as SLE were depicted as a large risk factor for patients with coronary artery disease (CAD). The study pinpointed SLE specifically to be the largest risk factor out of the study.28 Other epidemiological research studies showed that CVD risk factors had associations with cognitive impairment and lupus. This cognitive impairment also involved stroke based impairment along with hypertension, which supports the relationship between autoimmune diseases and vascular dementia.17 Recent studies have shown the impact of lupus on cardiovascular disease as a risk factor that is connected to CVD risk factors.27 A more focused project has shed light on coronary artery calcifications due SLE.24 These calcifications are dangerous for the cardiovascular system and could serve as indirect catalysts to a weakened blood vessel system that could involve cranial calcification. Various studies in the past have shown that lupus has a role in causing various plaque buildups, disruption of high density lipoprotein-low density lipoprotein (HDL-LDL) levels, 26
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and increased oxidative stress on the blood system.13 The pathology of CVD and autoimmune disease is highlighted in SLE/CVD studies showing that SLE in relation to the innate immune system has an impact on CVD. One experiment with mouse models has shown that autoreactive lymphocytes, specifically T-helper cells, cause fatty buildup resulting in artherogenesis.25 Focusing on Type 1 interferon (Type I IFN), a receptor in the initial immunological response of the body, new studies indicate that these cytokines also have a role in causing endothelial structure to deteriorate in lupus patients. This injury in the blood vessels will cause the expansion of vascular lesions.13 When considered in a cerebrovascular aspect, white matter lesion expansions serves to propagate further risk factors of VaD through perfusion. Humoral immunity research has shed light on the relationship of oxidized low-density lipoprotein (LDL), a type of cholesterol that develops into foam cells, which can cause early forms of CAD. Other research studies have shown the benefit of oxidized LDL that may prevent CAD, and as such more research is needed to understand the mechanism of oxidized LDL.25 Another innate immunity concern for lupus/ CVD conditions is thrombosis via neutrophils, which is a white blood cell that is a major component of the immune system.7 Patients with lupus have neutrophils that are more prone to programmed cell death. This relatively newly discovered mechanism of cell death has been shown to be involved in thrombosis. A type of stroke involving thrombosis could cause great cerebral damage leading to vast VCI. The disease models researching this are new and ongoing, but atherosclerosis has been used as a comparison model, strongly supporting the link between neutrophil death and thrombosis. Other studies highlight the fact that lupus has been shown to activate platelets which serve as mediators of immunity inflammations. Patients with these activated events were shown to have more vascular complications than normal. Activated platelets have also been shown to be an active component of artherothrombosis, a very dangerous risk for VCI from cranial arterial thrombosis.13 Atherosclerosis is a common risk factor for VaD due to the nature of it being a main branching source of CVD. It is likely that risk factors for atherosclerosis and lupus overlap and are correlated as seen in various studies. One study shows that patients with SLE have greater insulin levels and, thus, have a greater risk of having metabolic syndrome. Both these con-
ditions factor into the diagnosis of atherosclerosis as well.4 The Framingham Risk Factors for atherosclerosis do not explain the relationship between atherosclerosis and SLE alone.25 Framingham Risk factors are defined as traditional factors that are associated with coronary heart disease, which have connections to SLE as discussed above. Other predictors in SLE patients that may develop atherosclerosis involve the treatment of SLE. Corticosteroid therapy for SLE patients has been shown to increase the prevalence of atherosclerosis. There is a positive correlation between the intensity and duration of this therapy method on SLE and likelihood of the development of atherosclerosis. While other studies have shown that steroid therapy’s anti-inflammatory effects benefit patients against lupus and atherosclerosis, the overall picture implies that various unique factors of the individual being treated for SLE will have variability in regards to metabolism and anti-inflammation which could alter cardiovascular risk and benefit of undergoing steroid therapy.2 Consecutive studies have shown a link between SLE and aortic atherosclerosis or aortic stiffness. Increase in inflammatory activity due to lupus causes endothelial dysfunction, adhesion propagation, vascular smooth cell proliferation, and deposition of extracellular matrix and collagen. This hyperactivity leads to oxidative stress on the vascular system of the aorta resulting in atherosclerosis. Premature aortic stiffness is also caused by this same pathology and was seen to be independent of age in SLE patients. This implies that aortic stiffness is common in young SLE patients as well as the older cohort making this a risk factor for VaD for a wide range of ages.21,22 Population studies have clarified any ambiguity between arterial stiffness and atherosclerosis by showing that they are strongly associated with each other, meaning that many patients with one of these conditions could suffer double jeopardy in regards to risk factors.20 Aortic stiffness and atherosclerosis have been proven to cause hypoperfusion of the brain leading to VCI. Links between the central circulation and the brain is seen through dementia patients who show large cognitive decline correlating to more arterial stiffness in the aorta and other vessels.19 Post-stroke dementia and VaD are classifications that go almost hand in hand due to the cerebrovascular pathologies of both. Cohort and nation-wide studies of populations with SLE have shown that there is some increase in prevalence of stroke for these groups.3,16 Analysis of literature and various research
studies have shown the vascular implications of lupus on ischemic stroke through causes such as atherosclerosis, hypertension, and homocysteine. Homocysteine in particular is an amino acid that has been found to interact with a lupus anticoagulant that in turn supports cerebral atherosclerosis and ischemia.26 Cerebral amyloid angiopathy (CAA), as discussed earlier, is a major player in the pathogenesis of dementia. Its relation to VaD could be attributed to its link to the autoimmune reaction of the body. Neurological studies show that the concentrations of Aβ plaques could be related to interactions between autoimmune activity and inflammation through an unknown mechanism.18 Causing CAA in the brain is a major threat to cognition as it allows progressive white matter lesions to take root along with causing microinfarcts, microbleeds, and short-term hemorrhaging as detected through MRIs.15 Antiphosphoplipid antibody syndrome (APS) is another autoimmune complication that is known for coagulation and blood clots caused by the said antibodies reacting against bodily proteins. Having a high prevalence relationship with SLE, APS is a likely risk factor in cerebrovascular cognitive damage to the brain. Clinical manifestations of APS can include occlusions, thrombosis, infarctions, and ischemic attacks.1 Causation is rooted in the platelet fibrin blockage from antiphospholipid-induced endothelial cell reaction mechanisms involving anticoagulation inhibition and other complex actions regarding anticoagulation proteins, platelets, and fibronolytic dysfunction. VaD is a common consequence of APS, especially in the younger generation as seen in population studies with young people with multi-infarct dementia.5 A more recent case report has shown that hypercoagulability is not the only bridge between VaD and APS, but also increased atherosclerosis pathology and neural toxicity has been observed to be related according to neurological data. The study highlighted these concepts in tandem with the impact that APS had on brain metabolism and perfusion which caused large loss of neural activity in the form of dementia.9 A patient study showed the progression of VaD in a younger patient with APS and SLE where multi-infarction led to extensive cognitive decline and central nervous system lupus.8 This patient is a severe example of the implications of multiple autoimmune diseases working through multiple cerebrovascular pathologies of VaD.
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Conclusion
As seen in various forms of analyses, research studies, and case reports on VaD, SLE, APS, and CVDs, the overlap between all of these diseases is evident. The limited knowledge of individual pathologies of APS and also, to an extent, SLE, raises concern for a lack of continuity between autoimmunity effects on cognitive impairment. It is without a doubt that the need for further research into autoimmune disease is important as the implications for these diseases are not limited to single sphere of the human physiology but linked to the cardiovascular system and subsequently to the brain. Cognitive decline and destructive autoimmunity activity within the body is a threat that is being observed in populations independent of age groups, which is a main focal point for dementia-related studies. Another note of concern for future literary analysis and research is the relationship of gender and autoimmunity with respect to VaD, which was not covered in this review. As such, interdisciplinary research involving cardiovascular pathology, immunology, and neuropathology is vital in increasing awareness of autoimmunity as a dementia risk factor that is comparatively independent of age.
Acknowledgements
I would like to thank Baylor University Central Libraries for reference assistance.
References
1. Asherson, R.A.; Cervera, R.; Merrill, J.T.; Erkan, D. Antiphospholipid Antibodies and the Antiphospholipid Syndrome: Clinical Significance and Treatment. Semin. Thromb. Hemostasis. [Online] 2008, 34, 256-266. 2. Bruce, I.N. Not only…but also’: factors that contribute to accelerated atherosclerosis and premature coronary heart disease in systemic lupus erythematosus. Rheumatology (Oxford, U. K.). [Online] 2005, 44, 1492-1502. 3. Chun-Chih, C. et al. Increased Risk of Ischemic Stroke in Patients with Systemic Lupus Erythematosus: A Nationwide Population-based Study. Intern. Med. (Tokyo, Jpn.) [Online] 2012, 51, 17-21. 4. Chung, C.P. et al. High prevalence of the metabolic syndrome in patients with systemic lupus erythematosus: association with disease characteristics and cardiovascular. Ann. Rheum. Dis. [Online] 2007, 66, 208-214. 5. Coull, B.M.; Levine, S.R.; Brey, R.L. The Role of Antiphospholipid Antibodies in Stroke. Neurologic 28
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Clinics. 1992, 10, 125-143. 6. Enciu, A. et al. Neurobiology of Vascular Dementia. J. Aging Res. [Online] 2011, 2011. 7. Fuchs, T.A.; Brill, A.; Wagner, D. D.; NET impact on deep vein thrombosis. Arterioscler., Thromb., Vasc. Biol. [Online] 2012, 32, 1-14. 8. Fukui, T.; Kawamura, M.; Hasegawa, Y. Kato, T.; Kaga, E. Multiple Cognitive Impairments Associated with Systemic Lupus erythematosus and Antiphospholipid Antibody syndrome: A Form of Progressive Vascular Dementia? Eur. Neurol. 2000, 43, 115-116. 9. Hilker, R.; Thiel, R.; Geisen, C.; Rudolf, J. Cerebral blood Flow and glucose metabolism in multi-infarct dementia related to primary antiphospholipid antibody syndrome. Lupus. 2000, 9, 311-316. 10. Iadecola, C. The Pathobiology of Vascular Dementia. Cell Press [Online] 2013, 80, 844-866. 11. Ikejima, C. et al. Multicenter population-based study on the prevalence of early onset dementia in Japan: Vascular dementia as its prominent cause. Psychiatry Clin. Neurosci. [Online] 2014, 68, 216-224. 12. Jefferson, A.L.; Gentile, A. M.; Kahlon, R. Vascular Dementia. In Handbook of Alzheimer’s Disease and Other Dementias; Budson A.E.; Kowall N.W., Ed.; Wiley-Blackwell: Chichester, 2011; pp 92-115. 13. Knight, J.S.; Kaplan, M.J. Cardiovascular disease in lupus: insights and updates. Curr. Opin. Rheumatol. [Online] 2013, 25, 1-16 . 14. Lee, A.Y. Vascular Dementia. Chonnam. Med. J. [Online] 2011, 47, 66-71. 15. McKee, A.C; Gavett, B.E. The Neuropathology of Dementing Disorders. In Handbook of Alzheimer’s Disease and Other Dementias; Budson A.E.; Kowall N.W., Ed.; Wiley-Blackwell: Chichester, 2011; pp 249-253. 16. Mikdashi, J.; Handwerger, B.; Langenberg, P.; Miller, M.; Kittner, S. Baseline Disease Activity, Hyperlipidemia, and Hypertension Are Predictive Factors for Ischemic Stroke and Stroke Severity in Systemic Lupus Erythematosus. J. Am. Heart Assoc. [Online] 2007, 8, 281-285. 17. Murray, S.G. et al. Cardiovascular disease and cognitive dysfunction in systemic lupus erythematosus. Arthritis Care Res. [Online] 2012, 64, 1328-1333. 18. Piazza, F. et al. Anti–Amyloid b Autoantibodies in Cerebral Amyloid Angiopathy–Related Inflammation: Implications for Amyloid-Modifying Therapies. Ann. Neurol. [Online] 2013, 73, 449-458. 19. Picano, E.;Bruno, R.M.; Ferrar, G.F.; Bonuccelli, U.; Cognitive impairment and cardiovascular disease: So
near, so far. Int. J. Cardiol. [Online] 2014, 175, 21-29. 20. Popele, N.M. et al. Association between Arterial Stiffness and Atherosclerosis: The Rotterdam Study. J. Am. Heart Assoc. [Online] 2001, 32, 444-460. 21. Roldan, C.A.; Joson, J.; Qualls, C.R.; Sharrar, J.; Sibbitt, W.L. Premature aortic stiffness in systemic lupus erythematosus by transesophageal echocardiography. Lupus. [Online] 2010, 19, 1599-1605. 22. Roldan, P.C.; Joson, J.; Qualls, C.R.; Sharrar, J.; Sibbitt, W.L. Aortic Atherosclerosis in Systemic Lupus Erythematosus. Rheumatology (Sunnyvale) [Online] 2014, 5, 1-26. 23. Romรกn, G.C. Vascular Dementia; Distinguishing Characteristics, Treatment, and Prevention. J. Am. Geriatr. Soc. [Online] 2003, 55, 296-304. 24. Romero-Diaz, J. et al. Systemic lupus erythematosus risk factors for coronary artery calcifications. Rheumatology (Oxford, U. K.) [Online] 2012, 51, 110-119. 25. Sherer, Y. Shoenfeld, Y. Mechanisms of Disease: atherosclerosis in autoimmune diseases. Nat. Clin. Pract. Rheumatol. [Online] 2006, 2, 99-106. 26. Timlin, H; Petri, M. Transient ischemic attack and stroke in lupus erythematosus. Lupus [Online] 2013, 22, 1251-1258. 27. Wang, X.Y.; Tang, X.Q. Huang, Y.J.; Chen, W.Y.; Yu, X.Q. Frequency of established cardiovascular disease and its risk factors in Chinese patients with systemic lupus erythematosus. Clin. Rheumatol. [Online] 2011, 31, 669-675. 28. Zoller B.; Li, X.; Sundquist, J;. Sundquist, K. Risk of Coronary Heart Disease in Patients Hospitalized for Immune-Mediated Diseases: A Nationwide Follow-Up Study from Sweden. PLoS One. [Online] 2011, 7, 1-8.
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Review Article
Guanfacine Extended-Release: A Non-Psychostimulant Drug Treatment for Attention Deficit/Hyperactivity Disorder Jack A. Olmstead Department of Psychology and Neuroscience, Baylor University, Waco, Texas Abstract
This review seeks to examine the efficacy, safety profile, pharmacokinetics, pharmacodynamics, and mechanism of action of GXR as adjunctive or stand-alone treatment for children and adolescents with ADHD. A literature search was conducted using relevant keywords in Google Scholar (limits 1980-2014). A total of 6 clinical trials, 7 experimental/primary research articles, 6 review articles, and 1 meta-analysis were retrieved from the search and chosen for inclusion on the basis of direct contribution and/or supplementation to the material reviewed herein. A review of the literature concluded that GXR was effective in attenuating symptoms of ADHD as reported by scores on the Change in ADHD Rating Scale IV (ADHD-RS-IV) as well as lowering scores on the oppositional subscale of the ADHD-RS-IV. GXR was generally well tolerated with most side effects subsiding with continued administration.
Introduction
Since the first national US surveys of incidents of diagnosis administered to parents in 1997, a sharp increase in Attention-Deficit/Hyperactive Disorder (ADHD) has pushed the disorder to the forefront of public and psychiatric awareness. With this increase in diagnoses comes the burden of finding new behavioral interventions as well as the need for safer novel pharmacotherapies. Guanfacine extended release (GXR), a selective α2A adrenergic receptor agonist, is one such drug developed by Shire pharmaceuticals and approved by the United States Food and Drug Administration for the treatment of ADHD in children and adolescents. ADHD is characterized by pervasive inattention, impulsivity, and inappropriately high amounts of motor activity. These symptoms can be precipitated in previously healthy human subjects by injury to the right prefrontal cortex (PFC), an area known to mediate executive function through allocation of attentional resources toward pertinent stimuli. The right PFC is connected with other association areas including the temporal and parietal cortices.3,4 The PFC has also been shown to be the center for visuospatial working memory (WM) in primates; that is, it has the ability to 30
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store short-term information in the absence of sensory stimuli through recurrent excitation of spatially tuned pyramidal neurons in the dorsolateral PFC.3-5,12 The firing of these pyramidal neuron-constructed microcircuits appears delicately regulated and requires a precise neuromodulatory environment that correctly balances levels of catecholamines, acetylcholine, glutamate, and GABA in order to operate optimally. Activation of α2A adrenergic receptors (α2A-ARs) and D1 dopaminergic receptors serves to inhibit pyramidal cAMP-HCN channel mechanisms. Activated (open) HCN channels hyperpolarize the cell and reduce firing, which impairs working memory and precipitates symptoms characteristic of ADHD. Subjects with ADHD possess suboptimal levels of catecholamines as a result of genetic setpoints for norepinephrine (NE) and dopamine (DA) systems,22 along with other possible abnormalities in subcortical structures and cortex-to-cortex connectivity. Psychostimulants like methylphenidate (MPH), amphetamine (AMPH), and lisdexamphetamine,7 or nonstimulant drugs such as clonidine or guanfacine act to pharmacologically augment endogenous norepinephrine
and dopamine, artificially altering neurotransmission in ADHD individuals in an effort to mimic normal activity. Historically, psychostimulants have served as the first-line method for treatment of the disorder,21 but guanfacine is shown to be a promising alternative to the drugs.
Methods
The objective of this paper is to provide a review of all the relevant literature on the topic. A Google Scholar search was conducted with the keywords guanfacine, guanfacine extended release, ADHD, human, alpha 2a adrenergic receptor agonist, and nonstimulant, yielding 342 results. Review of the abstracts of the retrieved literature prompted exclusion of a number of irrelevant articles. Thirty papers aggregated from the database search, the author’s previous knowledge, or reference sections in articles found in the database search were identified and included in the present review. Sources were included based on their data reporting guanfacine’s mechanism of action, pharmacokinetics, efficacy in reducing symptoms of ADHD, side effects, safety, and any other considerations deemed relevant by the author.
Results Pharmacodynamics and Mechanism of Action
Clonidine and guanfacine have differential affinity for subtypes of the α2-adrenergic receptor (AR) family, which accounts for their differences in pharmacological profile. As a nonselective α2-AR agonist, clonidine binds to all members of the α2-AR receptor family (consisting of the α2A, α2B, and α2C subtypes), which have been reported by MacDonald and Scheinin in 1995 to be distributed throughout the brain in patterns specific to each receptor.17 Guanfacine has been shown to have up to 12 times more binding affinity for the α2A-AR subtype,27 which is predominantly localized in the PFC,1 than clonidine. However, guanfacine still binds to the other α2-AR subtypes at sufficiently high doses. Activation of PFC α2A-ARs results in inhibition of adenyl cyclase (AC), the enzyme that synthesizes cyclic adenosine monophosphate (cAMP). This inhibited AC activity reduces cAMP levels postsynaptically and indirectly decreases opening of cAMP-sensitive hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that normally hyperpolarizes and stabilizes cells via increased K+ conductance. This K+ efflux
serves to prevent the neuronal excitation necessary for optimal working memory.4,30 Normal endogenous activation of the α2A receptor serves to transmit signals of contextually relevant stimuli,4,18 e.g. allocating attention to a lecturing professor rather than the typing of nearby students. Suboptimal activation of α2A-ARs is seen in low catecholaminergic activity that can precipitate fatigue, lethargy, and ADHD. Binding of guanfacine to peripheral adrenergic receptors may give rise to its profile of cardiovascular effects such as hypotension and reduced heart rate. Though many studies report that these changes are statistically insignificant, the effects are still reported.2, 14, 16, 29,31 Because of its designed selective affinity for α2AARs compared to its tricyclic predecessor clonidine, guanfacine binds to receptors both in the central and peripheral nervous system. These molecular interactions precipitate its effects in reducing symptoms of ADHD as well as the cardiovascular side effects observed.
Efficacy
GXR has been approved for the treatment of ADHD in children and adolescents both as a short- and longterm adjunctive therapy with psychostimulants9,28,32 as well as stand-alone monotherapy.1,10-11,23-24 The drug has been shown to significantly reduce symptoms of ADHD in children and adolescents as measured by scores on the ADHD Rating Scale IV (ADHD-RS-IV), a parent-completed battery based on diagnostic criteria put forth by the preeminent psychiatric practitioner’s reference guide, the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). GXR has also been shown to reduce oppositional symptoms (described as “anger, hostility, irritability, arguing, and refusing to comply with rules set by adults”),10 reported by the ADHD-RS-IV oppositional subscale, that are commonly comorbid with diagnosed ADHD.10 In a meta-analysis of three different clinical trials of GXR in children with ADHD conducted by Faraone and Glatt,11 they found a dose-dependent relationship between both actual doses and adjusted mg/kg doses, and reduction in ADHD-RS-IV scores. Predictably, the highest dose of 4 mg showed the largest decrease in symptoms reported by parents. A preliminary open-label, non-placebo, dose-escalation study conducted by Hunt, Arnsten, and Asbell in 1995 surveyed 13 child and adolescent subjects (mean age 11.1) taking once daily doses of SPRING 2015
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GXR beginning at 0.5 mg/day and titrated daily up to optimal dose of a maximum 4 mg/day.14 The study reported significant decreases in symptoms measured by the Conners’ 31-Item ADHD Questionnaire as well as reductions in psychomotor hyperactivity (i.e. fidgeting, restlessness, vocal outbursts) and improved sociability among peers. Transient adverse side effects, including headache, nausea, and daytime sleepiness, were experienced in a relatively small number of patients. In most patients, these symptoms normalized to insignificant levels after 2 weeks. No significant cardiovascular events or changes were reported. The DSM-III diagnostic criteria, lack of control group, small treatment group size, and open-label nature of the study temporized the results to some extent, but when examined holistically, the treatment effects of GXR portrayed in the trial corroborate the data seen in later studies conducted with more rigorous parameters and controls. A more recent study conducted by Spencer et al. in 200928 explored the efficacy of GXR in children and adolescents from ages 6-17 who were already taking AMPH or MPH but experiencing suboptimal effects. The design of the trial was a multicentered, open-label, dose-escalation paradigm, surveying 75 subjects. The study found predictable decreases in symptoms reported by ADHD-RS-IV in response to GXR even after patients had been on a steady, assumedly optimized dose of amphetamine or methylphenidate for a month or longer before undergoing guanfacine administration. Wilens et al. (2012) conducted a randomized, placebo-controlled, double-blind, dose-optimization clinical trial documenting adjunctive GXR with AMPH or MPH.32 In this study, 461 child/adolescent subjects ages 6-17 were randomly distributed in a 1:1:1 ratio into groups that were administered a placebo, a morning dose of GXR along with the normal dose of stimulant they had been taking for at least a month prior (GXR AM), and an evening dose of GXR with their regularly administered stimulant (GXR PM). Similar to the study done by Spencer et al., both GXR AM and GXR PM groups showed marked decreases in ADHD symptoms (reported by ADHD-RS-IV scores) compared to the group receiving placebo treatment. One unique factor reported in the study was effect size based on subtypes of ADHD. The GXR PM subjects displayed larger effect sizes compared to the GXR AM group in total ADHD-RS-IV scores, with efficacy measures reported at 0.447 and 0.377, respectively. GXR PM treatment also surpassed AM dosing efficacy in 32
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the inattention subscale but had lower efficacy scores on the Hyperactivity/Impulsivity subscale compared to morning doses. In addition, the mean adjusted dose reported by Wilens et al. was 0.088 ± 0.04 mg/kg compared to the mean 0.07 mg/kg optimized by investigators in the study published by Spencer el al.28 A study by Sallee et al. used a double-blind, 9-week, dose-ranging, multicenter trial to measure the clinical effectiveness of monotherapeutic GXR in 211 subjects aged 6-17 that completed the treatment in attenuating symptoms of ADHD in diagnosed individuals.24 Doses of GXR were administered in 4 amounts of 1, 2, 3, or 4 mg/day, depending on the treatment group. At endpoint, all groups displayed significant reduction in overall ADHD-RS-IV scores in a dose-dependent manner compared to the placebo group, with the 4 mg/day group having the largest effect size. Subscores of Inattentiveness and Hyperactivity/Impulsivity were also significantly lowered compared to placebo. Overall reports of efficacy, measured using scores on the Clinical Global Impression Improvement (CGI-I) score, were compiled in a recent meta-analysis of randomized, controlled clinical trials studying GXR.23 Fifty-nine percent of 1177 pediatric patients aged 6-17 years old experienced beneficial treatment effects for ADHD, measured by a CGI-I score ≤ 2. Considering that the drug showed significant improvement of ADHD symptoms in every trial, especially when noting the variability of study protocols, guanfacine is shown to be effective in treating ADHD.
Safety/Side Effects
The most common side effects from guanfacine administration (typically measured as present in ≥5% of subjects receiving GXR) are nausea, headache, upper abdominal pain, irritability, and events of sedation, somnolence, and fatigue (SSF). These effects were almost always transient in nature and reduced to negligible amounts in all the short-term (≤ 9 weeks) studies examined.14,24,28,32 Side effects were usually mild to moderate in nature when present. One meta-analysis of a wider range of trials than reviewed herein reports that treatment-emergent adverse effects (TEAEs) were experienced by 82.4% of the 948 patients receiving GXR compared to 67.9% of the 376 placebo-receiving patients.23 Interestingly, a 2-year, open-label, follow-up study to the trial reported in Sallee et al., 2009 conducted again by Sallee et al. reported a 77.1% dropout rate from the original 257-patient analysis set.24 The investigators report only 12.0% of the total cases of
discontinuation were due to TEAEs, but such low rates of patient continuation illustrate the need for more investigation of long-term agreeability of guanfacine for pediatric patients. It should be noted that all comparisons of TEAEs between the studies conducted between Hunt et al., 199514/Spencer et al., 200928 and Sallee et al., 200924/ Wilens et al., 201232 are part of a tentative, side-by-side presentation of data reported in the studies and do not preclude confounds associated with the open-label and double-blind natures of the individual trial designs, respectively, as well as potential drug interactions between guanfacine and stimulants in the articles discussing adjunctive therapy. However, considering the reports of the four studies taken together, guanfacine shows a large margin of safety and tolerable side effects that prove it a viable drug for pediatric ADHD treatment. Sedation, somnolence, and fatigue events Sedation, somnolence, and fatigue (SSF) events, including symptoms reported as fatigue, tiredness, daytime sleepiness, sedation, somnolence, or any other symptoms deemed similar by the author, were observed during early points in treatment in all the shortterm (≤ 9 weeks) trials reviewed when GXR was administered both in adjunctive treatment with another stimulant and in monotherapeutic paradigms.1,14,24,28,32 SSF events declined over time in these studies, with the exception of the Hunt et al. article where timeline occurrence of TEAEs was not reported. In fact, in the meta-analysis of three monotherapeutic clinical trials done by Faraone and Glatt in 2009 which analyzed different studies with similar parameters to those reviewed in this paper, the authors found that TEAEs including SSF events were not statistically correlated to actual dose, mg/kg dose, or weight, but reported that the most predictive factor for TEAEs was instead the amount of time subjects had been administered GXR treatment. Corroborating these data, Sallee et al. report that TEAEs that included SSF events “typically resolved by study end [9 weeks]” in their trial investigating monotherapeutic GXR.24 A controlled, double-blind study of GXR in conjunction with stimulants showed that treatment-emergent SSF events did indeed occur (which is notable taken together with the behaviorally activating effects of psychostimulants) and resolved by week 8.32 Spencer et al. also reported that treatment-emergent SSF events occurred in 56%
of subjects but resolved after means of 10.5 or 13.0 days between subjects taking GXR in conjunction with AMPH or MPH, respectively. These events typically occurred 18-23 days after onset, theoretically precipitating only after the 21-day mark when the dose was optimized in all subjects.28 Considering the results from each study, it is clear that guanfacine’s sedative effects are generally tolerable and decline to negligible levels with continued administration. Long-term agreeability and safety of the drug are both positive factors that in all but exceptional cases prove guanfacine a viable option for pediatric treatment. Cardiovascular effects Guanfacine has been shown to be a hypotensive agent, presumably through its known action on α2-ARs.1,14,20,27 One study reported that cardiovascular events or changes such as “blood pressure decreases, although frequent, were rarely rated by investigators as ‘adverse events.’”28 The total mean reduction in heart rate among the AMPH and MPH groups was -4.4 beats per minute at the treatment endpoint in the Spencer et al. study.28 Both studies of adjunctive GXR and stimulant pharmacotherapy reported overall small decreases in systolic and diastolic blood pressure (BP) as well as heart rate that were statistically insignificant.28,32 This is notable considering amphetamine and methylphenidate’s hypertensive effects. Further studies are needed to conclude if adjunctive therapy with GXR can counterbalance the hypertensive cardiovascular side effects of the psychostimulants. A randomized, placebo-controlled, double-blind, dose-escalation trial was conducted in an attempt to describe the cardiovascular effects of abrupt cessation vs. taper down titration of guanfacine immediate release (GIR) treatment in a small number (n = 27) of healthy adults.16 The study concluded that sudden stoppage of up to 4 mg/day GIR treatment did not precipitate effects that were dangerous or clinically significant in measures of rebound systolic blood pressure, diastolic blood pressure, or heart rate compared to taper-down titration subjects or placebo-receiving controls. Overall, guanfacine shows an assuring cardiovascular safety profile, providing families with a history of cardiac complications an alternative to psychostimulants when considering ADHD pharmacotherapy. SPRING 2015
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Other considerations One study hypothesized that guanfacine would decrease binge-like eating behaviors in rats,6 considering the fact that reboxetine, an NE reuptake inhibitor that indirectly increases activity at all adrenergic receptors, has been shown by Fassino et al. to significantly decrease events of binge eating in humans.6 Rats were exposed to a feeding schedule designed to model human binge eating behaviors. The schedule the treatment group underwent consisted of regular food ad libitum as well as twice weekly access to the palatable binge food for 30 minutes on Days 3 and 6 of 7-day feeding cycles. Rats were normalized to the schedule before beginning guanfacine treatment. Contrary to the investigators’ hypothesis, guanfacine was associated with an increase in binge eating. The study found that chronic administration of 0.05 mg/kg guanfacine was correlated with a significant increase in binge calories consumed (“sweetened fat” food made from vegetable shortening and 10% sucrose) compared to pre-treatment consumption. One of the authors’ explanations for this was that the cognitive processes augmented by guanfacine may have resulted in more effective goal-seeking behaviors and consequently more palatable food consumption. Practitioners considering pediatric GXR prescription for ADHD should take these findings in to account when faced with patients that have comorbid eating disorders. A different study explored a new method in examining central NE levels via growth hormone (GH) levels.13 GH levels are known to increase when subjects are administered clonidine. The main objective of the study was to assess noradrenergic differences in children with ADHD and comorbid reading disabilities. However, the findings are relevant considering they also report increases in GH following acute 0.02 mg/kg guanfacine administration. Because guanfacine is administered predominantly to children and adolescents, the GH level disturbances it elicits are especially disturbing considering the critical period of growth most patients taking the drug are experiencing. However, the study reported that GH levels rose sharply approximately 40 minutes after oral administration of guanfacine, then immediately began to decline until reaching baseline levels in 180 minutes,13 long before guanfacine metabolism would have produced any significant changes in plasma levels of the drug. Both the influence on GH hormone levels and 34
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the evidence of increase in binge-like eating patterns necessitate close involvement and monitoring by practitioners and parents of children taking guanfacine.
Pharmacokinetics
One study of guanfacine extended release in ADHD subjects reported that 1, 2, 3, or 4 mg doses had a half-life (t1/2) of 14.4 ± 2.39 hours in children and 17.9 ± 5.77 hours in adolescents.8 Another study showed GXR possessed a t1/2 of 16.9 ± 4.2 hours in adults.29 It has also been reported that guanfacine displays linear pharmacokinetics among all age groups.8,29 The long half-life of GXR is advantageous, considering its use as a once daily treatment of ADHD symptoms. GXR’s manufacturer, Shire Pharmaceuticals, reports that after oral administration the drug is absorbed quickly and “widely distributed throughout various tissues,”26 resulting in “low plasma levels achieved in spite of high bioavailability of the drug.” The median time required (Tmax) for GXR to reach maximum plasma concentrations (Cmax) after a single 2 mg dose was 4.98 hours in children aged 6-12 and 4.96 hours in adolescents aged 13-17.8 The reported Cmax showed disparity between children and adolescents, with a mean of 2.6 ± 1.03 ng/mL in the former group and 1.7 ± 0.43 in the latter.8 The authors report that this is likely because of the heavier average body weight of adolescents compared with younger subjects. In the same study, the area under the plasma concentration-time curve from zero to infinity (AUC∞) was predictably lower in adolescents (47.3 ± 13.69 ng×hr/ ml) compared with children (65.2 ± 23.88 ng×hr/ml).8 Repeated daily administration of both 2 mg and 4 mg GXR resulted in a return to starting blood levels in both children and adolescents, allowing for safe daily use. Administration near in time to consumption of high fat food has been reported by Shire to increase absorption of GXR.19 Metabolism of guanfacine occurs mainly through glucuronidation by liver microsomal enzyme CYP 3A4,26-27 with the rest (24-37%) being excreted through urine unchanged.27 GXR is not known to inhibit any other CYP450 enzymes,19 but its own metabolism, mediated by CYP 3A4, is subject to impaired rates by co-administration of known CYP 3A4/5 inhibitors, such as ketoconazole.26 GXR also increases levels of valproic acid through an unknown process when the two are comorbid.26 Like all drugs, administration of guanfacine warrants constant caution and avoidance of other com-
pounds that may interact or be contraindicated.
Conclusion
Guanfacine displays a high affinity for α2A adrenoreceptors and is assumed to mediate its effects through its inhibition of cAMP-HCN channel mechanisms that impair stimulus processing in the PFC, though its mechanism for reduction of ADHD symptoms is not known. Binding of guanfacine ligands also has accompanying side effects most commonly manifesting as headache, irritability, upper abdominal pain, and SSF events. These undesirable effects begin with mild to moderate severity and typically reduce to negligible presence in the individual with continued treatment. Based on this review, guanfacine extended release appears to be a safe, efficacious, once-daily treatment for ADHD in children and adolescents both as adjunctive therapy with psychostimulants such as amphetamine-based drugs or methylphenidate28,32 and as a stand-alone therapy.14,24 Currently, the FDA has only approved guanfacine for treatment in children and adolescents with ADHD, although promising research suggests its efficacy in reducing adult symptoms as well.15 More investigation in large-scale, controlled trials is needed to approve the drug for widespread and approved treatment in adults. Considering holistically its clinical profile, guanfacine seems to serve effectively as another addition to the treatment possibilities available for practitioners to help improve the quality of life for those affected by ADHD.
Acknowledgments
I thank Dr. Jim Patton of the Department of Psychology and Neuroscience at Baylor University for his suggestions.
References
1. Aoki C.; Go, C.G.; Venkatesan C.; Kurose, H. Perikaryal and synaptic localization ofα2a-adrenergic receptor-like immunoreactivity. Brain Res. 1994, 650, 181-204. 2. Arnsten A.F.; Cai J.X.; Goldman-Rakic P.S. The alpha-2 adrenergic agonist guanfacine improves memory in aged monkeys without sedative or hypotensive side effects: Evidence for alpha-2 receptor subtypes. J. Neurosci. 1988, 8, 4287-4298. 3. Arnsten, A.F.T. The neurobiology of thought: The groundbreaking discoveries of patricia goldman-rakic
1937-2003. Cereb. Cortex. 2013, 23, 2269-2281. 4. Arnsten, A.F.T.; Wang, M.J.; Paspalas, C.D. Neuromodulation of thought: Flexibilities and vulnerabilities in prefrontal cortical network synapses. Neuron. 2012, 76, 223-239. 5. Arnsten, A.F.T.; Paspalas, C.D.; Gamo, N.J.; Yang, Y; Wang, M. Dynamic network connectivity: A new form of neuroplasticity. Trends Cogn Sci. 2010, 14, 365-375. 6. Bello, N.T.; Walters, A.L.; Verpeut, J.L.; Caverly, J. Dietary-induced binge eating increases prefrontal cortex neural activation to restraint stress and increases binge food consumption following chronic guanfacine. Pharmacol. Biochem. Be. 2014, 125, 21-28. 7. Berridge, C.W.; Devilbiss, D.M. Psychostimulants as cognitive enhancers: The prefrontal cortex, catecholamines, and attention-deficit/hyperactivity disorder. Biol. Psychiat. 2011, 69, 101-111. 8. Boellner, S.W.; Pennick, M.; Fiske, K.; Lyne, A.; Shojaei, A. Pharmacokinetics of a guanfacine extended-release formulation in children and adolescents with attention deficit/hyperactivity disorder. Pharmacotherapy. 2007, 27, 1253-1262. 9. Childress, A. Guanfacine extended release as adjunctive therapy to psychostimulants in children and adolescents with attention-deficit/hyperactivity disorder. Adv. Therapy. 2012, 29, 385-400. 10. Connor, D.; Findling, R.; Kollins, S.; Sallee, F.; López, F. et al. Effects of guanfacine extended release on oppositional symptoms in children aged 6-12 years with attention-deficit hyperactivity disorder and oppositional symptoms. CNS Drugs. 2010, 24, 755-768. 11. Faraone, S.V.; Glatt, S.J. Effects of extended-release guanfacine on adhd symptoms and sedation-related adverse events in children with adhd. J. Atten. Disord. 2009, 13, 532-538. 12. Goldman-Rakic, P.S. Cellular basis of working memory. Neuron. 1995, 14, 477-485. 13. Halperin, J.M.; Newcorn, J.H.; McKay, K.E.; Siever, L.J.; Sharma, V. Growth hormone response to guanfacine in boys with attention deficit hyperactivity disorder: A preliminary study. J. Child Adol. Psychop. 2003, 13, 283-294. 14. Hunt, R.D.; Arnsten, A.F.T.; Asbell, M.D. An open trial of guanfacine in the treatment of attention-deficit hyperactivity disorder. J. Am. Acad. Child Psy. 1995, 34, 50-54. 15. Jakala, P. et al. Guanfacine, but not clonidine, improves planning and working memory performance in humans. Neuropsychopharmacology. 1999, 20, 460-470. 16. Kisicki, J.C.; Fiske, K.; Lyne, A. Phase i, douSPRING 2015
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ble-blind, randomized, placebo-controlled, dose-escalation study of the effects on blood pressure of abrupt cessation versus taper down of guanfacine extended-release tablets in adults aged 19 to 24 years. Clin. Ther. 2007, 29, 1967-1979. 17. MacDonald, E.; Scheinin, M. Distribution and pharmacology of alpha 2-adrenoceptors in the central nervous system. J. Physiol. Pharmacol. 1995, 46, 241258. 18. Meyer, J.S. Quenzer, L.F. Psychopharmacology: Drugs, the Brain, and Behavior. 2 ed.; Sinauer Associates, Inc.: Sunderland, MA, 2013. 19. Muir, V.; Perry, C. Guanfacine extended-release. Drugs. 2010, 70, 1693-1702. 20. Newcorn, J.H.; Clerkin, S.; Schulz, K.P.; Halperin J.M. Alpha2-adrenergic agonists: Clonidine and guanfacine. In Pediatric psychopharmacology, 2 ed.; Martin, A.; Scahill, L.; Kratochvil, C., Ed.; Oxford University Press: 2010; p 263. 21. Pliszka, S. Practice parameter for the assessment and treatment of children and adolescents with attention-deficit/hyperactivity disorder. J. Am. Acad. Child Adolesc. Psychiatry. 2007, 46, 894-921. 22. Tannock, R. et al. Towards a biological understanding of adhd and the discovery of novel therapeutic approaches. In Animal and Translational Models for CNS Drug Discovery: Psychiatric Disorders. McArthur, R.A.; Borsini, F., Ed.; Academic Press: New York, 2008; p 301. 23. Ruggiero, S. et al. Guanfacine for attention deficit and hyperactivity disorder in pediatrics: A systematic review and meta-analysis. Eur. Neuropsychopharm. 2014, 24, 1578-1590. 24. Sallee, F.R.; Lyne, A.; Wigal, T.; McGough, J.J. Long-term safety and efficacy of guanfacine extended release in children and adolescents with attention-deficit/hyperactivity disorder. J. Child Adol. Psychop. 2009, 19, 215-226. 25. Sallee, F.R. et al. Guanfacine extended release in children and adolescents with attention-deficit/hyperactivity disorder: A placebo-controlled trial. J. Am. Acad. Child Psy. 2009, 48, 155-165. 26. Shire Pharmaceuticals. FDA approves Intuniv速 (guanfacine) extended-release tablets for use as adjunctive therapy to stimulants for the treatment of adhd in children and adolescents. (Available from http://www.shire.com/shireplc/en/investors/irshirenews?id=453.) 27. Sorkin, E. Heel, R. Guanfacine. Drugs. 1986, 31, 301-336. 36
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28. Spencer, T.J.; Greenbaum M.; Ginsberg, L.D.; Murphy, W.R. Safety and effectiveness of coadministration of guanfacine extended release and psychostimulants in children and adolescents with attention-deficit/hyperactivity disorder. J. Child Adol. Psychop. 2009, 19, 501-510. 29. Swearingen, D.; Pennick, M.; Shojaei, A.; Lyne, A.; Fiske, K. A phase i, randomized, open-label, crossover study of the single-dose pharmacokinetic properties of guanfacine extended-release 1-, 2-, and 4-mg tablets in healthy adults. Clin. Ther. 2007, 29, 617-625. 30. Wang, M. et al. Alpha 2a-adrenoceptors strengthen working memory networks by inhibiting camp-hcn channel signaling in prefrontal cortex. Cell. 2007, 129, 397-410. 31. Wilens, T.E. Mechanism of action of agents used in attention-deficit/hyperactivity disorder. J. Clin. Psychiat. 2006, 67, 32-37. 32. Wilens, T.E. et al. A controlled trial of extended-release guanfacine and psychostimulants for attention-deficit/hyperactivity disorder. J. Am. Acad. Child Psy. 2012, 51, 74-85.
Abstract
Investigating an ESKAPE to Nosocomial Infections
Kyra Curtis, Diane Hartman, D.V.M., and Jacquelyn Duke, Ph.D. Department of Biology, Baylor University, Waco, Texas ESKAPE pathogens are responsible for a wide range of nosocomial infections. The pathogenicity of ESKAPE pathogens and the growing threat of their antibiotic resistance have increased a demand for new antibiotics. Since the 1940s humans have benefited from substances naturally produced and collected from in situ bacteria. Pharmaceutical companies have altered natural products by adding functional groups to extend the effects and minimize dosage. We are replicating the original protocols to isolate and identify novel substances to fight ESKAPE pathogens. Organisms were isolated from soil samples from both Tacoma, Washington and Waco, Texas. These colonies were tested against ESKAPE pathogens for evidence that pathogen growth was suppressed. 7 isolated colonies from the Tacoma sample and 8 isolates from the Waco sample displayed zones of inhibition, indicating that these isolates had greater potential for producing effective antibiotic substances than others based on patch plate results. Retesting this spring revealed only 1 of the 7 organisms from Tacoma and all 8 isolates from Waco continued to produce zones of inhibition; gram staining and various media tests were performed on these organisms in effort to identify their characteristics. Diluted samples of each isolate were mixed with Taq polymerase in PCR tubes, and each sample was treated with 27F and 1492R primers to extract the desired nucleotide sequence. The thermo-cycled samples were sent for DNA analysis. One was identified as Serratia marcescens, and ID of the other isolates and their subsequent antibacterial secretions could lead to the discovery of new antibacterial compounds and products.
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Abstract
Risk Factors Associated with Post-Operative Nausea and Vomiting Christina Hagan, Marygayle Martin, and Caleigh Cole Providence Health Center, Waco, Texas
A third of all patients who undergo anesthesia suffer from Post-Operative Nausea and Vomiting (PONV), a condition that may cause severe physical discomfort and psychological distress as well as increased recovery time following procedures.1 Past research has identified factors that correlate with high levels of PONV including: gender, race, non-smoking status, history of motion sickness, history of PONV, and history of GERD.2 This highlights the need for therapies to reduce PONV as well as unified consensus concerning treatment. This study examines the PONV demographic of patients admitted to Outpatient Services at Providence Hospital and explores risk factors associated with PONV as well as efficacy of treatments including alcohol swabbed on the nose and administration of crackers and ginger ale/sprite. In this observational, case-control study, six hundred subjects completed a questionnaire indicating their PONV level on a severity scale. Within this study, 18% of subjects claimed to have experienced PONV. Women experienced PONV more frequently than men (p<0.05, χ2 = 0.98271) and younger-aged adults reported PONV with increased incidence (p<0.01, χ2 = 1). The results of this study suggest a positive relationship between PONV and fluids administered (p<0.01, χ2 = 0.999). Positive responses from the small number of patients who recorded outcomes from administration of crackers, ginger ale, and alcohol on the nose suggest that these treatments may be beneficial in reducing PONV, but should be further assessed. These results will aid health professionals at Providence Hospital in identifying patients that are high-risk for PONV and in managing symptoms.
References
1. Mace, L. An audit of post-operative nausea and vomiting, following cardiac surgery: scope of the problem. Nurs. Crit. Care. 2003, 8, 187-196. 2. Pfisterer, M.; Ernst, E. M.; Hirlekar, G.; Maser, P.; Shaalan, A. K.; Haigh, C.; Upadhyaya, B. Post-operative nausea and vomiting in patients undergoing day-case surgery: an international, observational study. Ambul. Surg. 2001, 9, 13-18.
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URSA â&#x20AC;&#x201C; Research Presentation STEM Award
Femoral Neck Axil Length: Biological Profile of Deceased Undocumented Immigrants Audrey Murchland Collaborators: Lori Baker, Angie Christensen (FBI), Rebecca Meeusen Department of Anthropology, Baylor University, Waco, Texas
Since 1998, the bodies of more than 6300 undocumented immigrants have been discovered along the US-Mexico border. The Reuniting Families Project (RFP) is an effort to recover, identify, and repatriate these remains. To begin the identification process, forensic anthropologists utilize population specific standards in the development of biological profiles. Ancestry and sex estimations are two important elements of these profiles. New, population-specific methodologies are always needed which can further improve the accuracy of these estimates. In this study, the femoral neck axis length (FNAL) was examined to determine its potential use in sex and ancestry estimations of undocumented border crossers (UBCs). Comparison samples included: 87 American Black, 108 American White, 91 Native American, and 58 UBC specimens. When classifying samples into ancestral groups with discriminant function analysis, FNAL provided very low classification accuracies, ranging from 34.7% to 40.4%. However, when classing samples into males and females with DFA, FNAL provided high classification accuracies ranging from 83.4% to 91.4%. The sectioning point then calculated for UBCs, in particular, provided an averaged classification rate of 89.85%. The results of this study show considerable promise for the future use of FNAL in forensic anthropology.
URSA â&#x20AC;&#x201C; First Place for Research in Team Poster in Biology
Comparative Toxicity of Organophosphate Flame Retardants in Zebrafish
Aparna Sarode Collaborators: Gerardo Martinez, Samuel L. Huseman, Erika L. Abel, and Crystal Y. Usenko Department of Biology, Baylor University, Waco, Texas Organophosphate flame retardants (OPFRs) are compounds used to delay the ignition of materials manufactured in the textile and furniture industries. OPFRs have a wide range of chemical structures that may attribute to their biologic al activity in organisms inadvertently exposed to these chemicals. In order to examine the effects of OPFRs on development, zebrafish (Danio rerio) were used as a model organism. The well-defined stages of growth, rapid development, and transparent body of zebrafish embryos make them an ideal organism to monitor changes induced by exposure to OPFRs. Zebrafish embryos were exposed at 6 hours post fertilization (hpf), and evaluated daily for morbidity and mortality until 144 hpf. In order to probe a potential mechanism of action, the Glutathione S-transferase (GST) activity was assessed as an indicator of potential oxidative stress on homogenized samples extracted from zebrafish exposed at 120 hpf. Several OPFRs induced increased mortality and morbidity in a concentration dependent manner up to 20 ppm; however, there was a wide variety in calculated lethal concentrations (LC50). Due to the wide range of effects and rising production of OPFRs, further research should be conducted to ensure human and environmental safety.
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URSA – First Place in Individual Poster in Biology
Overexpressing Endogenous APP using the Novel TALE-TF Technology Jade Connor Collaborators: Joachim Herz, Theresa Pohlkamp Department of Biology, Baylor University, Waco, Texas
The amyloid β (Aβ) precursor protein (APP) is one of the major proteins affecting Alzheimer’s disease (AD) pathogenesis. Processing of APP releases Aβ, which forms toxic oligomers that accumulate in the hallmark plaques seen in the brains of AD patients. Interestingly, APP is highly expressed in the kidneys, in addition to the brain. The structural and functional similarities between the neurons in the brain and the podocytes in the kidney are expansive: they release some of the same compounds, have similar mechanisms for regulating exocytosis, and participate in advanced cellular communication. In this study, we used the TALE-TF (transcription activator-like effector transcription factor) technology to increase the endogenous expression of APP in two different cell lines. Using immunocytochemistry and Western Blotting to characterize the expression levels of APP in transfected N2A and bEnd.3 cells, we have shown that APP levels increase two fold for N2A (neuroblastoma) cells and three fold for bEnd.3 (brain microendothelial) cells, statistically significant increases. Our results support that TALE-TFs can be utilized to increase the endogenous expression of APP in the cell lines studied, elucidating a new tool that can be used to increase APP levels in mouse models of AD and glomerular diseases with podocyte damage. This technology, when controlled by a TRE (tet responsive element) promoter induced by a CRE-lox system, would make mouse models more applicable to the progression of AD and glomerular disease as it occurs in humans.
URSA – First Place in Individual Poster in Environmental Science
Geospatial Distribution of Environmental Soil Pb in Two Urban Areas Scott Biebas Collaborators: E. Spencer Williams and Ray W. Brown Department of Environmental Science, Baylor University, Waco, Texas
Over 60 years of exposure to lead (Pb) from numerous sources has left urban soils with Pb concentrations that often greatly exceed health guidelines. In numerous studies looking in urban environments, soil Pb concentrations have been found to be a good indicator of children’s blood Pb levels. Decades of research on Pb has failed to identify an accepted dose below which a child is considered unaffected. In 2012, the Centers for Disease Control and Prevention established a blood Pb concentration of 5 mg/dL to identify children and environments associated with lead-exposure hazards. As a result of this lowering of the recommended action level, recent efforts to assess urban Pb contamination and determine low-level effects of Pb on children have demonstrated that areas once considered safe may be causing Pb poisoning. This project will examine historical sources of heavy metals in two urban areas: Memphis, TN and West Dallas, TX and compare the contributions of both leaded gasoline and historical smelter activities to residential soil Pb concentrations respectively. In addition, some of this data will be used to determine the potential contribution of soil Pb exposures to blood Pb data collected as part of a larger study looking at neurocognitive development in children in collaboration with The Urban Child Institute in Memphis, TN and the Department of Preventive Medicine at the University of Tennessee Health Science Center. 40
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URSA – First Place Team Poster in Environmental Science
Residential Exposure to Indoor and Outdoor Volatile Organic Compounds
John Kou, Stacy Sebastian, Luis Rodriquez, Nikhik Patel, Justin McClain, Lindsay McCaulay, and Lyanne Lara Collaborators: Dr. Sascha Usenko Department of Environmental Science, Baylor University, Waco, Texas Polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic compounds with known mammalian toxicity. Sources of PAHs are naturally-occurring or anthropogenic. The Occupational Safety and Health Administration (OSHA) has set PAH air quality standards at of 0.2 mg/m3. In our research, high volume air samplers were utilized at a United States Department of Agriculture site in Riesel, TX to assess PAH concentrations. Samples were collected via a quartz fiber filter and measured using gas chromatography/mass spectrometry. PAHs were measured in concentrations ranging from 0.31 µg/m3 (± 0.41) to 7.17 µg/m3 (± 0.85). Though these concentrations do not exceed OSHAs standard, the presence of these compounds is concerning due to the possibility of their origins being from larger Texas cities miles away from Riesel, a rural area. This would indicate the potential for PAHs, persistent in nature, to affect locations far away from their production sites.
URSA – First Place in Individual Poster in Geology
Using Paleosols to Reconstruct Paleoclimate in the Lake Victoria Region, Kenya Nicole Arellano Collaborators: Emily Beverly, Daniel Peppe, Steven Driese Department of Geology, Baylor University, Waco, Texas
Lake Victoria, the largest lake in Africa by surface area, has expanded and contracted throughout time in response to climate change. This study uses paleopedology to reconstruct the environment of this area during the Late Pleistocene, when modern humans dispersed across and out of Africa, in order to better understand the role climate may have played in this event. A series of three paleosols from Kisaaka, a major fossil and artifact-bearing site located near Karungu, Kenya along the eastern margin of Lake Victoria, were described and sampled. The oldest is a paleo-Vertisol, identified by its pedogenic slickensides, wedge peds, and gilgai topography that indicate precipitation seasonality. It is overlain by two weakly developed paleo-Inceptisols. Layers of tuff separate the paleosols, suggesting that volcanic eruptions interrupted pedogenesis. Clay mineralogy of the paleosols was analyzed using X-ray Diffraction. Results indicate that smectite dominates the paleosols, although palygorskite and illite are also minor constituents. Geochemical analysis and CALMAG and CIA-K proxies estimated mean annual precipitation (MAP) values of 700-900 mm/yr, significantly less than the modern MAP of ~1400 mm/ yr. Vertic features, clay mineralogy, and MAP proxies suggest a paleoenvironment and paleoclimate much drier than today, consistent with fossil fauna, which is dominated by alcelaphine antelopes and zebras indicative of semi-arid grasslands. Data obtained from Kisaaka paleosols, combined with paleontological evidence from Karungu, suggest a seasonally dry, open grassland environment for the Lake Victoria region during the Late Pleistocene, different from the closed bushland and forest habitats present today. SPRING 2015
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URSA â&#x20AC;&#x201C; First Place in Individual Poster in Physics
Chaos in Inelastic Billiards
Martin Martinez Jr. Collaborators: Jeffrey Olafsen, Ph.D. Department of Physics, Baylor University, Waco, Texas Mathematical models such as the logistic map are simple low dimensional systems that exhibit chaos as a single parameter is varied. Using such simple systems allow us to better understand chaos in more complicated settings. Billiards are simple systems used to investigate Hamiltonian Dynamics. When real billiards are studied the energy lost in each collision must be replaced by an external stimulus to maintain the dynamics. We are furthering a prior investigation to examine chaos in an inelastic gravitational billiard system. In the current experiment, the motion of the particle near a horizontally shaken vertical boundary will be examined for the presence of chaos. In addition, the geometry will allow us to better study the velocity dependence of the inelasticity in the system.
URSA â&#x20AC;&#x201C; First Place in Team Poster in Physics
Radiation Damage Studies of Scintillators and Fibers for the CMS HCAL Adryanna Smith Collaborators: Geoffrey Morizot, Nate Chaverin, Daryl Hare, Ph.D. Department of Physics, Baylor University, Waco, Texas
The Large Hadron Collider (LHC) at CERN is poised to begin Run 2, a new era of operation at a proton-proton collision energy of 13 TeV. In preparation for the higher energy and intensity of the proton beams, many improvements are being made to the Compact Muon Solenoid (CMS) detector. In particular, the Hadron Calorimeter (HCAL), the component of the CMS detector that gathers information on hadrons produced in proton-proton collisions, has experienced higher-than-anticipated radiation damage after receiving a dose of about 100 kRad during Run 1. This damage resulted in severe signal degradation, which will be exacerbated in Run 2 as the LHC operates at a higher intensity. To gain insight into the cause of this damage, we conducted a longitudinal study of the annealing process of irradiated HCAL scintillator materials and optical fibers. The dose rate and total dose of radiation, as well as the presence of oxygen, were studied as factors of annealing. Results of the study proved that a higher total dose causes permanent damage to scintillators and fibers, and also that oxygen is necessary for the annealing process. Ultimately, however, the HCAL materials examined in the study do not appear sufficiently damaged to account for the signal degradation observed in the actual HCAL.
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URSA – First Place in Individual Poster in Psychology & Neuroscience
The Family Resiliency Index: Examining a New Measure of Family Resiliency Mitchell Todd Collaborators: Keith Sanford, Ph.D. Department of Psychology and Neuroscience, Baylor University, Waco, Texas
Family resiliency is the extent to which the relationship(s) between family member(s) has adaptive characteristics that facilitate an individual’s, dyad’s, or system’s ability to cope with stressful life situations. Existing theory on family resiliency has resulted in numerous measures compose d of several dimensions and subscales, yet these measures are often not consistent in their composition, and dimensions are often highly correlated with one another. One new and promising tool for measuring the resiliency of a dyad after a stressful event is the Family Resiliency Index (FRI). Unlike other measures of resiliency, the FRI is designed to measure resiliency in terms of positive and negative interactions as two orthogonal dimensions. In addition to both positive and negative subscales not being highly correlated with one another, both subscales are designed to be highly correlated with other measures of family resiliency. Furthermore, it is expected that the positive FHI scale will be positively correlated with well-being and negatively correlated with externalized behavioral problems, while the negative FHI scale should be negatively correlated with well-being and positively correlated with externalized behavior problems. In the present study, college students reflected on a stressful event in their family from their childhood. This scale is continuing to be evaluated, and in this preliminary step, retrospective reports from young adults were used to ensure that a variety of stressful events could be identified.
URSA – First Place in Team Poster in Psychology & Neuroscience
Short Sleep Is Associated with Prospective Memory Impairments
Madison Krueger Collaborators: Mericyn Daunis, Sarah Thomas, Claudina Tami Department of Psychology and Neuroscience, Baylor University, Waco, Texas Total sleep deprivation has been experimentally linked to impairments on demanding nonfocal prospective memory tasks (Grundgeiger, Bayen, & Horn, 2013). We investigated whether habitual sleep duration was associated with performance on focal and nonfocal prospective memory tasks, which differ in the extent to which they rely on relatively automatic spontaneous retrieval processes (focal) versus cognitively demanding strategic monitoring processes (nonfocal). Thirty undergraduate students performed a focal prospective memory session (word prospective memory targets during ongoing tasks that require the processing of semantic features of whole-words) and a nonfocal prospective memory session (initial-letter prospective memory targets during a lexical decision task). Participants maintained a sleep diary for up to seven days prior to each session. We observed a significant positive association between mean sleep duration and nonfocal prospective memory (r=.40), but no association with focal prospective memory (r=.00). Short sleepers (<7 hrs/night) detected fewer nonfocal prospective memory targets (M=.29) than normal sleepers (7-9 hrs/night; M=.77), p<.001. These results were consistent with theories of prefrontal cognitive dysfunction associated with sleep loss, and extend prior findings by demonstrating that even the naturalistic sleep restriction that many undergraduates routinely subject themselves to may cause similar prospective memory impairments as a night of total sleep deprivation. SPRING 2015
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About the Authors
Original Research
EDTA Assisted Phytoremediation of Copper by Cattail Plants - p. 9 Ben Caputo is a sophomore majoring in Biochemistry and minoring in the Medical Humanities. Ben is from Newport Beach, California and plans on pursuing an M.D./PhD after graduating from Baylor University. His academic interests are in biomedical cardiovascular research. Kathryn Gleason is a sophomore Health Science Studies major from Scottsdale, Arizona. Her future plans include attending Physician Assistant School after graduation and pursuing a career in the rehabilitation field. Camila Albo is a sophomore Health Science Studies major from Houston, Texas. After graduating in May 2017, Camila plans on conducting public health research for one year before entering an M.D./M.P.H. program.
The Effects of Varying Burn Intensities on Plant Growth - p. 13 Jennifer Teague is a sophomore Biology major from Flower Mound, Texas. Her academic interests include biology, the medical humanities, and chemistry. She plans to attend medical school in Texas and become an OB/ GYN physician. She would like to incorporate research into her career if possible and would want to attend a medical school with research opportunities. John Bowersox is a sophomore Biochemistry major from Clear Lake, Texas. His academic interests are in genetic research on human development and its applications in medicine and everyday life. He plans on either going to medical school and becoming a pediatrician or clinical geneticist, or pursuing a masterâ&#x20AC;&#x2122;s degree in genetics. Kirk Reeves is a sophomore Biochemistry major from Austin, Texas. His academic interests are in ecological research and research concerning the endocrine system. He plans to go to medical school and specialize in either orthopedics or cardiology.
Studies of Synthetic Hydroxyheme and Heme Oxygenase - p. 19 Regina Martinez Lorenzo is a senior Biochemistry major from Mexico City, Mexico. Her academic interests include biochemistry, epidemiology, epigenetics, medicine, and public health. She plans to attend either medical school at the University of Indiana or a school of public health at Columbia University or New York University.
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Review Articles
The Path to Vascular Dementia via Autoimmunity: A Review - p. 22 David Le is a sophomore Biochemistry major, minoring in Biology, from Friendswood, Texas. He is currently interested in biomedical research involving either immunopathology or bioorganic drug development, and intends to enter a MD-PhD program after graduation.
Guanfacine Extended-Release: A Non-Psychostimulant Drug Treatment for Attention Deficit/Hyperactivity Disorder - p. 30 Jack Olmstead is a sophomore Neuroscience major and Mathematics minor from San Diego, California. His academic interests include visuospatial working memory, functional connectivity, prefrontal cortex disorders (e.g. ADHD, Schizophrenia, Antisocial Personality Disorder), synaptic plasticity, psychostimulant pharmacology, and drug dependence pathology. He plans to pursue a Ph.D. in Neurobiology, complete a postdoctoral fellowship, and conduct independent research at a private institution.
Abstracts
Investigating an ESKAPE to Nosocomial Infections - p. 37 Kyra Curtis is a sophomore Biology major from Colorado Springs, Colorado. She is is enthusiastic about her biology studies and is also dedicated to her research project on the ESKAPE pathogens and new antibiotics. Apart from the science disciplines, Kyra enjoys literature and Latin. She volunteers at Baylor Scott and White in the NICU and also tutors children at La Vega Junior High School in Waco. Kyra plans on pursuing an MD-PhD degree after her undergraduate years at Baylor to work as a researching physician. This summer, Kyra will further her research pursuits as a fellow at the Mayo Clinic, working on infectious disease of the nervous system.
Risk Factors Associated with Post-Operative Nausea and Vomiting - p. 38 Christina Hagan is a junior Biology major from Rochester, Minnesota. Her academic interests include biology, biochemistry, and zebrafish research. She plans to attend medical school and pursue a career as an academic physician. Marygayle Martin is a junior Biochemistry major from Tyler, Texas. Her academic interests include biochemistry, genetics, and tuberculosis research. She plans on applying to medical school and aspires to become a physician. Caleigh Cole is a junior Biology major from San Antonio, Texas. Her academic interests include cardiology, clinical research, and cell biology. She plans to attend medical school and pursue a career as a physician.
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URSA Abstracts
Femoral Neck Axil Length: Biological Profile of Deceased Undocumented Immigrants - p. 39 Audrey Murchland is a senior Anthropology major from San Antonio, Texas. Her academic interests include epidemiology, osteology, and the social determinants of health. She will be attending the University of Michigan in the fall to pursue a MPH in Epidemiology.
Comparative Toxicity of Organophosphate Flame Retardants in Zebrafish - p. 39
Aparna Sarode is a Honors sophomore Biochemistry major from Cypress, Texas. Her academic interests include biology, chemistry, clinical research, and bench research. She plans to attend medical school and pursue a career as a pediatrician.
Overexpressing Endogenous APP using the Novel TALE-TF Technology - p. 40
Jade Connor is a sophomore Biology major from Lewisville, Texas. In addition to her interest in Alzheimer’s Disease research at a molecular level, Jade also enjoys epidemiological and clinical research. Upon graduating from Baylor, she plans to attend medical school and continue research while practicing as a physician
Geospatial Distribution of Environmental Soil Pb in Two Urban Areas - p. 40
Scott Biebas is a sophomore Environmental Health major from Pflugerville, Texas. His interests are in heavy metal toxicology. He plans to get a master’s degree in epidemiology.
Residential Exposure to Indoor and Outdoor Volatile Organic Compounds - p. 41
John Kou is a senior Environmental Health Science major from Andover, Massachusetts. His interests include epidemiology, infectious diseases, tropical diseases, and urban planning. He plans to intern at the Centers for Disease Control and Prevention in Atlanta and eventually become a public health physician.
Using Paleosols to Reconstruct Paleoclimate in the Lake Victoria Region, Kenya - p. 41 Nicole Arellano is a senior Geology major from Graham, Texas. Her academic interests include hydrology, fluvial geomorphology, and soil science. She plans to attend graduate school at Oregon State University and earn a master’s degree in Water Resources Science.
Chaos in Inelastic Billiards - p. 42 Martin Martinez is a junior double major in Physics and Mathematics from San Antonio, Texas. His academics interests include being involved in the Society of Physics Students, physics discussions, and research. He plans on pursuing a career in the science field either as a lab researcher or engineer technician.
Radiation Damage Studies of Scintillators and Fibers for the CMS HCAL - p. 42
Adryanna Smith is a sophomore University Scholar concentrating in Physics and Linguistics from Paris, TN. She is especially motivated in high energy particle physics, experimental research, and cross-cultural linguistics. She plans to apply to graduate school for physics and work towards a career in research and professorship.
The Family Resiliency Index: Examining a New Measure of Family Resiliency - p. 43
Mitchell Todd is a senior Psychology major from Austin, Texas. His research interests include family functioning and resiliency after stress, parenting styles/behaviors, and children’s internalizing and externalizing behavior and its effects on future functioning. He plans to work toward his Ph.D. in clinical psychology.
Short Sleep Is Associated with Prospective Memory Impairments - p. 43
Madison Krueger is a junior Neuroscience major from Keller, Texas. Her academic interest include early brain development, prospective memory, and polysomography to study sleep. She plans to continue neuroscience research in graduate school. 46
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Scientia For Prospective Authors Mission Scientia shall provide a professional platform upon which undergraduates of Baylor University are able to publish personally conducted and outstanding research in the areas of biological sciences, physical sciences, mathematics, and technology.
Accepted Formats Research Articles presenting original research conducted by current undergraduate level students enrolled at Baylor University. Research articles must include an abstract, introduction, materials and methods, up to six figures or tables, results, and discussion. (Maximum 4500 words, including captions and references.) Review Articles synthesizing developments of interdisciplinary significance written by current undergraduate level students enrolled at Baylor University. Review articles must include an abstract and an introduction outlining the topic of discussion. (Maximum 6000 words, including captions and references.) Abstracts proposing research topics currently being investigated by current undergraduate level students enrolled at Baylor University. For formatting guidelines and submission instructions, please see our website: http://baylor.edu/burst/index.php?id=863108
For Prospective Editors Are you interested in joining our editorial team? Would you like to help design the next Scientia? Please contact us at baylorburst@gmail.com.
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