Microbiology World
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Chief Editor Mr. Sagar Aryal (Founder) Ambassador, iversity M.Sc. Medical Microbiology St. Xavier’s College, Nepal
Editors Mr. Saumyadip Sarkar ELSEVIER Student Ambassador South Asia 2013 Ph.D Scholar (Human Genetics), India Mr. Avishekh Gautam Ph.D Scholar Hallym University, South Korea Mr. Manish Thapaliya Ph.D Scholar, China Mr. Hasnain Nangyal M.Phil. Department of Botany, Hazara University, Pakistan Mr. Sunil Pandey ELSEVIER Student Ambassador South Asia 2014 B.Sc. Medical Microbiology Nobel Medical College, Nepal
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Table of Content Page No. Microbial Indicators: Role in monitoring of drinking water quality and health prospects
5-8
Prevalence and prevention of thalassemia in Khyber-Pakhtunkhwa, Pakistan
9-11
Do you have cold? Fomites may be responsible
12-13
Chinese Salt
14-19
Prions: The Killer Proteins
20-28
Hybridoma Technology: A Tool in immunotherapy
29-37
Lyophilisation: A Method of Preserving Biologicals
38-43
Rapid diagnosis of acute respiratory infections by multiplex endpoint PCR technology
44-47
Bioweapons: A new trend in emerging Sciences
48-58
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Microbial Indicators: Role in monitoring of drinking water quality and health prospects Gaurav Saxena, Rohan Kanaujia and Ram Naresh Bharagava* Department of Environmental Microbiology (DEM), School for Environmental Sciences (SES), Babasaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar, Raebareli Road, Lucknow 226 025 (U.P.), India Correspondence E-mail Address: bharagavarnbbau11@gmail.com Ensuring the safety of drinking water is an ongoing process. Water that looks perfectly transparent and clean may be contaminated with pathogens, which may cause serious health hazards. A clean and safe drinking water supply may be the norm in European and American countries, but in developing countries, the assessment of clean water is not the rule and therefore, the waterborne illness outbreaks are common. It is reported that around two and a half billion people have no access of improved sanitation and more than 1.5 million children die each year from diarrheal diseases (Fenwick 2006). A number of disease occur due to contamination of drinking water with urban sewage, feces of infected humans and animals having different kinds of microorganisms, which are termed as enteric pathogens. However, the detail information on waterborne pathogens can be found in Cabral (2010). These include enteric bacteria, viruses and protozoa’s and can be transmitted by exposure to domestic waste either through swimming in contaminated water, ingesting contaminated water or eating vegetables that has been irrigated with contaminated water or grown in contaminated soil (WHO 2008). In general, any practice that involves the application of domestic wastewater in soil has potential to cause microbial contamination of ground water since treatment processes applied do not completely remove/inactivate microbial pathogens in wastewater (Figueras & Borrego 2010). The examination of drinking water for the presence of indicator microorganisms is a key to determine the microbiological quality and public health safety because their presence indicate the potential faecal contamination of water with pathogens and an index of quality deterioration. www.microbiologyworld.com
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Indicator microorganisms are generally not themselves human pathogens (Verhille 2013). This has been the foundation upon which the protection of public health from waterborne diseases has been developed. The most widely used indicator microorganisms are coliforms (total coliforms), faecal or thermo-tolerant coliforms, Escherichia coli, enterococci (Faecal streptococci or Intestinal enterococci) and bacteriophages. Further, the detail information on microbial indicators can be found in Cabral (2010) and Figueras & Borrego (2010) (Fig. 1).
Fig. 1: Microbial indicators in drinking water: Total coliform, faecal coliform and E. coli Adapted from (Verhille 2013)
The criteria for a microorganism to act as an ideal indicator of pathogens in water environment are as follows (Cabral 2010): a. The organism should be present whenever enteric pathogens are present and absent whenever pathogens are absent. b. The organism present at a density that has some constant direct relationship to the density of pathogens. c. The organism should be useful for the analysis of all types of contaminated environmental waters. d. The organism should not grow in contaminated water. e. The organism should be non-pathogenic to humans and easily identifiable. www.microbiologyworld.com
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The organism should survive in environment as long as possible.
g. The organism should be the member of intestinal micro-flora of warm-blooded animals. h. The organism should exist in high number in human intestine as well as in feces. i.
The organism should be detectable by easy, rapid and specific/sensitive, but economically viable methods
In addition, the potential application of an indicator microorganism should be to indicate: a. The fecal pollution. b. The presence of domestic sewage. c. The presence of microbial pathogens. d. The efficiency of a particular water or wastewater treatment process. e. The environmental fate of a target pathogen.
However, whether these indicator bacteria are the suitable indicator of human pathogens, it has been questioned because of some serious limitations they include (Girones et al., 2010): a. Sensitive to inactivation through wastewater treatment processes and sunlight exposure. b. Short survival period as compared to microbial pathogens. c. Not indicative of exclusive faecal source. d. Ability to multiply in some natural environments. e. Inability to recognize faecal contamination source (point or non-point). f.
Less correlation with pathogenic presence.
Further, it is also reported that the drinking water illness outbreaks have occurred both in presence or absence of indicator microorganisms and involved pathogenic microorganisms that have contaminated the drinking water and that either were not eliminated during the treatment process or later failed at the time of outbreak (Figueras and Borrego 2010). These outbreaks occurred despite the specific legislations that have been designed to prevent them (Figueras and Borrego 2010). The World Health Organization (WHO) is an active body in this field and has already published many guidelines/documents in collaboration with International Water Association (IWA) and www.microbiologyworld.com
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“Organization for Economic Co-operation and Development (OECD)” for improvement in drinking water quality (WHO 2008). Water safety plan is the most recent that ensure the safety of drinking water and can be found in the WHO technical guidance document and also available in WHO directory.
Nevertheless, the presence of indicator microorganisms will likely continue to be used as a criterion of drinking water quality. Although, there is no any perfect indicator microorganism and research is ongoing to find a suitable microorganism that can act as a better indicator for the presence of waterborne pathogens. Acknowledgement The authors are highly grateful to University Grants Commission (UGC), Government of India (GOI) New Delhi for financial support as “Start-Up grant” for this work and UGC Fellowship received by Mr. Gaurav Saxena is also duly acknowledged. References 1. Cabral, J. P. S. (2010) Water Microbiology. Bacterial Pathogens and Water. Int. J. Environ. Res. Public Health 7, 3657-3703. 2. Fenwick, A. (2006) Waterborne Diseases: could they be consigned to history. Science 313, 1077-1081. 3. Figueras, M. J., & Borrego J. J. (2010) New Perspectives in Monitoring Drinking Water Microbial Quality. Int. J. Environ. Res. Public Health 7, 4179-4202. 4. Girones, R., Ferrus, M. A., Alonso, J. L., Manzano, J. R., Calgua, B., Correa, A. D. A., Hundesa, A., Carratala, A., & Bofill-Mas, S. (2010) Molecular detection of pathogens in water- The pros and cons of molecular techniques. Water Res. 44, 4325-4339. 5. Verhille, S. (2013) Understanding microbial indicators for drinking water assessment: interpretation of test results and public health significance. National collaborating centre for environmental health. 1-12. 6. World Health Organization. (2008) Guidelines for drinking water quality. 3rd edn. (1) Geneva, Switzerland. www.microbiologyworld.com
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Prevalence and prevention of thalassemia in Khyber-Pakhtunkhwa, Pakistan 1
Maria Zubair, 2Tahir Hussain
1
Peshawar Medical and Dental College, Warsak Road Peshawar, KhyberPakhtunkhwa, Pakistan
2
Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
Abstract: Thalassemia is an inherited autosomal recessive blood disorder characterized by formation of abnormal haemoglobin which in turn leads to destruction of RBCs. Since it is a recessive trait and can be controlled, if planned properly, but because of lack of awareness and certain traditional and cultural practices thalassemiac babies are still reported from rural population of Khyber-Pakhtunkhwa province Pakistan. This report discusses the prevalence and various treatment options available for thalassemia patients in a treatment center at KhyberPakhtunkhwa, Pakistan. Introduction: Thalassemia is a form of inherited blood disorders, caused by weakening and destruction of RBCs (Red Blood Cells). The genetic determinants for thalassemia are present on autosomes and the condition arises when the genes are missing or variant of the genes are present. This causes the malfunction of the body to make normal haemoglobin (Hb). Life span of Red Blood cells (RBC) with normal haemoglobin (Hb) is 120 days while in thalassemia it becomes 10 to 15 days only.
Normally the majority of adult hemoglobin <Hb A> is composed of four protein chains i.e; two alpha and two beta globin chains arranged in a hetrotetramer form. In thalassemia, patients have defect either in alpha or beta globin chain causing production of abnormal RBC. www.microbiologyworld.com
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Common treatment options available in Pakistan: 1. Blood transfusion: Blood transfusion is a common option available for extending life expectancy of thalassemiacs. Since thalassemia patients need regular blood transfusions to sustain their life and multiple transfusions can result in iron overload which then results in severe physiological dysfunctions in the body. 2. Bone marrow transplantation: Bone marrow transplantation offers about 70% success rates in pakistan1. However it is an expensive surgery and costs about Rs. 30 lac in Pakistan 1. 3. Hydroxy urea: This drug is generally used in treatment of leukemia, breast cancer and malignancy. However, recently, this drug was found to be effective against thalassemia as well 1. According to the research, about 60% of patients didnâ&#x20AC;&#x2122;t need further blood transfusion while in remaining 40% there was decreased rate of blood transfusion noticed 1. As a case study in Hamza foundation Peshawar, a welfare organization providing healthcare services to thalassemiac children, exercised the hydroxy urea treatment strategy on about 160 patients, out of them 31 patients are not receiving any further blood transfusion from past 9 months1. However certain side effects of this drug, such as, leukocytopenia and bone marrow depression were noticed1. Prevalence: About 823 thalassemiac patients from all over Khyber-Pakhtunkhwa, Pakistan, registered at Hamza Foundation in seven years period 1. These figures are available only on our record. Of course there could be many more thalassemiac patients struggling for their life. 95% of the thalassemiac patients belong to poor, deserving and uneducated class 1. It is a troublesome disease common in children and young patients with extremely high mortality rate. Prevention: Prevention could be a better alternative as compared to expensive treatment. Since thalassemia is a hereditary condition so controlling thalassemia in the population will only be possible if thalassemia free babies are delivered. For this reason we need to take certain measures in order to prevent thalassemia in the coming generations. 1. Family marriages: Cousin marriages are quite common in villages and poor set up. For this purpose government should play its role in educating people about the hazards resulting from cousin marriages. www.microbiologyworld.com
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2. Pre marriage screening: All the first and second relatives of known thalassemia patients should be screened. If they are diagnosed with diseased or carriers, their record should be kept in view so that they must not marry member from other thalassemiac family. 3. Prenatal screening: If a thalassemiac couple gets expected they must undergo prenatal screening i.e; CVS (Chorionic Villus Sampling) during first trimester. If the fetus is diagnosed as thalassemiac major then it must be aborted. Healthcare authorities and ethical bodies agree all over the world that aborting a fetus in certain conditions like for saving life of mother or if fetus is diagnosed to b abnormal is not illegal. 4. Spreading the awareness: Generally uneducated people in our population do not know the basic information regarding thalassemia. They should be properly educated about the causes and ways to prevent thalassemia. Awareness campaign should be launched through both electronic and print media. Radio, Tele vision, daily newspapers, magazines, distributing pamphlets, conducting seminars, guiding imam masjids, chodries and khans to educate people in their communities. Acknowledgement: We are grateful to Dr. Tariq khan, Hamza Foundation, for providing data about thalassemia patients. References: Hamza Foundation, 2-A Park Avenue, University Town Peshawar, Khyber-Pakhtunkhwa Pakistan.
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Do you have cold? Fomites may be responsible Oyediji Kehinde Eyitayo University of Abuja, Abuja, Nigeria The common cold is a viral infectious disease of the upper respiratory tract which primarily affects the nose. A cold usually begins with fatigue, a feeling of being chilled, sneezing and a headache, followed in a couple of days by a runny nose and cough, nasal congestion and a sore or scratchy throat, sometimes accompanied by loss of appetite, sneezing, hoarseness, watery eyes, low-grade fever, headache, and body aches. Symptoms may begin within 16 hours of exposure and typically peak two to four days after onset. The symptoms of the common cold will typically last anywhere from 4-14 days, with most individuals improving in one week. The common cold is the most common human disease and all peoples globally are affected. The common cold is generally mild and self-limiting with most symptoms generally improving in a week.
The common cold virus is typically transmitted via airborne droplets (aerosols), direct contact with infected nasal secretions, or fomites. Diseases that spread by droplet transmission, fecalâ&#x20AC;&#x201C; oral transmission, or contact transmission often do so by means of fomites. Germs commonly live on fomites for minutes or hours or sometimes even longer.
Fomites are inanimate objects that can carry pathogenic agents from one susceptible source to another. These objects can be anything, such as a handset, door knobs (handle), laboratory benches, laptop keypads, ATM machines, money, clothes, dishes, books, pens, silverware, or escalator hand rail. A cold virus can live on objects for several hours and can thus be acquired from contact with these objects. Fomite transmission works best on hard, durable surfaces like dishes, books, door knobs, telephones, and hand rails, all of which people come in contact with on a daily basis. Regular hand washing appears to be effective in reducing the transmission of cold viruses. Not touching the nose or eyes is another. Individuals with colds should always sneeze or cough into www.microbiologyworld.com
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a facial tissue, and promptly throw it away. If possible, one should avoid close, prolonged exposure to persons who have colds.
In the laboratory and other healthcare environments, gowns and disposable gloves are also used. Isolation, e.g. quarantine, is not possible as the disease is so widespread and symptoms are non-specific. Vaccination has proved difficult as over 200 different viral types are associated with colds and they mutate rapidly. Creation of a broadly effective vaccine is thus highly improbable. Zinc supplements may help to reduce the prevalence of colds. Routine vitamin C supplements do not reduce the risk or severity of the common cold, though they may reduce its duration. Because common cold viruses can survive up to three hours outside the nasal passages on inanimate objects and skin, cleaning environmental surfaces with a virus-killing disinfectant might help prevent spread of infection.
No medications or herbal remedies have been conclusively demonstrated to shorten the duration of infection. Treatment thus comprises symptomatic relief. Getting plenty of rest, drinking fluids to maintain hydration, and gargling with warm salt water, are reasonable conservative measures. One study has found chest vapor rub to provide some relief of nocturnal cough, congestion, and sleep difficulty. Treatments that help alleviate symptoms include simple analgesics and antipyretics such as ibuprofen and acetaminophen/paracetamol. Other decongestants such as pseudoephedrine are also effective in adults. Ipratropium nasal spray may reduce the symptoms of a runny nose but has little effect on stuffiness. Much of the benefit from treatment is however attributed to the placebo effect.
Antibiotics have no effect against viral infections and thus have no effect against the viruses that cause the common cold. Due to their side effects antibiotics cause overall harm, but are still frequently prescribed. Some of the reasons that antibiotics are so commonly prescribed include people's expectations for them, physicians' desire to help, and the difficulty in excluding complications that may be amenable to antibiotics. There are no effective antiviral drugs for the common cold even though some preliminary research has shown benefits.
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Chinese Salt 1
Ammara Nawaz, 2Hasnain Nangyal, 3Sikander Khan Sherwani, 4
Noor Nasir Khattak
1
Department of Zoology Punjab University
2
Department of Botany Hazara University Mansehra Khyber Pakhtoonkhwa
3
Department of Microbiology Fedral Urdu University of Arts Science & Technology Karachi
4
Assistant Professor Gynecology and Obstetrics Kohat Medical College Khyber Medical University
To say the history of salt is essentially the history of the world is not an overstatement. Some call salt a "primordial condiment," and rightfully so. It has been part of this earth for as long as there has been water and rock to create it. It has been a highly-valued commodity that served many purposes, but perhaps the most useful and powerful purpose is preservation. Salt has an uncanny ability to preserve just about anything, a vegetable or even a human cadaver. In the history some riots for salt are also been observed.
Several types of salts are used by man in foods and for different applications also. Some of them are Iodized table salt, table salt, sea salt, kosher salt, Chinese salt, pickling salt, black salt, Himalayan pink salt, flake salt, smoked salt, seasoned salt, Hawaiian salt and many more. Chinese salt is now a days a widely used salt in dishes. It is a white crystalline substance the sodium salt of glutamic acid that has little flavour itself but enhancesthe flavour of proteins either by increasing the amount of saliva produced in the mouth or by stimulating the taste buds used as a food additive especially in Chinese Formula: NaC5H8O4. It is also called sodium glutamate with abbreviation MSG. History of Chinese salt First stage of the story begins in 1908 with chemist Ikeda Kikunaeâ&#x20AC;&#x2122;s isolated this ingredient in sea kelp that gave flavor to konbu dashi, the standard Japanese broth. The product that www.microbiologyworld.com
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emerged from Ikeda’s laboratory, Monosodium glutamate was quickly patented in Japan, the United States, England, and France. In domestic announcements of his invention, Ikeda proposed calling its distinctive taste umami a term derived from the word in Japanese meaning “tasty.” Ikeda brought the powdered substance to iodine manufacturer Suzuki Saburo, whose Suzuki Chemical Company began marketing it in 1909 under the brand name Ajinomoto, meaning “essence of taste.”
Fig. 1: Varieties of salts used by man.
What are glutamates? Glutamate is one of the most general amino acids found in nature. It is the main component of many proteins and peptides, and is present in most tissues. Glutamate is also produced in the body and plays an essential role in human metabolism. Virtually every food contains glutamate. It is a major component of most natural protein foods such as meat, fish, milk and some vegetables. This amino acid has a flavor enhancing property in both free and combined state. It www.microbiologyworld.com www.facebook.com/MicrobiologyWorld
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is a major component of MSG, so when MSG is added into any food its flavor is enhanced due to presence of glutamate in it giving food an Umami flavor which is a meaty taste.
MSG and our Metabolism Our body is capable to digest MSG as it is capable to digest the naturally present amino acid glutamate. Our body metabolizes glutamate easily. Once glutamate has entered into the body of a human it metabolizes it and canâ&#x20AC;&#x2122;t distinguish between the origins of the amino acid. If it is a part of a tomato or MSG added into the food. MSG is low in sodium It is a popular belief that MSG contains high percentage of sodium ions .Actually MSG contains only one third the amount of sodium as compared to table salt. So it is safe to use by high blood pressure patients, heart patients and many more that canâ&#x20AC;&#x2122;t afford much sodium in their diet and also put a little effect on palatability even giving food a meaty more pleasant taste. Contradictory views about Chinese salt Many contradictory statements are there related to Chinese salt. Many people even scientists think that Chinese salt be not good for human health and has some health risks associated to it. Several aspects of Chinese salt in relation to human health are studied in detail. Some of these are discussed as below:
Chinese salt and pregnant women It was once thought that Chinese salt in not good for pregnant females, lactating mothers and the fetus or placenta. Now various studies have proved that MSG intake has no adverse effect in all above cases. It is known through deep investigations that the ratio of MSG in the blood cannot be increased by the intake (Chinese salt). Pitkin a scientist to see the effect of MSG increase on pregnant females and fetus conducted an experiment. He injected high amount of MSG in the blood of the Monkey pregnant female and noticed no increase in level of MSG blood level up to a dose of 220mg\kg of maternal weight. Thus no raise in level of blood MSG and no effect of it on the female and the fetus were concluded. www.microbiologyworld.com
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Chinese salt and lactating mothers No bad effect of Chinese salt was seen in lactating mothers too. By certain experiments this was proved. Lactating women were given MSG at about 100mg\kg of body weight and its effect was noticed on the mother and the infant. No increase of level of glutamate in human milk was seen and no effect was observed on the infant also. Naturally human milk has 10 times more ratio of glutamate in it as compared to cowâ&#x20AC;&#x2122;s milk. Thus MSG intake in diet was declared not a risk for the infants feeding on breast milk. Chinese salt and its neurological effects In the brain, glutamate serves as a neurotransmitter in addition to its general role in protein and energy metabolism. Concerns were raised in the late 1960s by John Olney, M.D., of Washington University, that high doses of MSG may adversely affect brain function. He examined the possibility of MSG-induced brain lesions through injection or force-feeding methods in rodents. But the dosage used in this experiment were very high not comparable to the amount of glutamate taken up by a man by using Chinese salt in his diet in normal days. Studies say that an amount of 40g\kg weight of the man of MSG is even safe which is actually 5000 times then normally taken amount by a man.
In another experiment by Bazzano it was also concluded that MSG has no bad effect on humans. In this experiment 11 humans were given 147g\day of MSG for about 42 days and no side effects were observed in them.
William Pardridge, M.D pointed up that dietary glutamate does not enter the brain because the blood-brain barrier maintains a transport system for acidic amino acids, such as glutamate, to effectively exclude circulating glutamate from the brain. Pardridge also showed that the levels of brain glutamate do not rise or fall with changes in plasma glutamate levels. This point was strengthened by many other investigations by many scientists.
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Thus it was concluded that ordinary daily intake level of MSG has no bad effect on human brain and nervous system.
Chinese salt and hypersensitive reactions Many people are observed by scientists having allergy to some food products or substance such as cheese or peanuts etc due to many reasons. Some scientists questioned if Chinese salt or MSG may be allergic to some people. Several investigations were made to study this hypothesis.
In 1991, after reviewing the literature on MSG and food allergy and safety, a panel of the American College of Allergy, Asthma and Immunology concluded that MSG is not an allergen and reaffirmed its safety as a food ingredient.45. More recently, Ronald Simon, M.D., department of allergy and immunology, Scripps Clinic, La Jolla, California, conducted a welldesigned, double-blind, placebo-controlled study of 65 subjects with chronic urticaria. None of the subjects exhibited positive reactions to doses of 2.5 g of MSG. Chinese salt in relation to children health It has been speculated that children would metabolize oral MSG more slowly than adults. However, research conducted by Stegink and colleagues at the University of Iowa showed that children as young as one year old metabolize glutamate as effectively as adults.
Chinese salt and Asthma Early poor studies said that MSG might be a cause of asthma. However further controlled investigations pointed out that it is not the case. MSG was not a cause of asthma. In an experiment humans were given 25g\kg weight of MSG per day for a few days. No difference in pulmonary reactions was noted in these humans. In 1991 and 1993, researchers from the National Institutes of Healthâ&#x20AC;&#x2122;s Institute of Allergy and Infectious Diseases presented data analyzing the possible association of MSG to asthma. In one study, they challenged 13 non-asthmatics and 30 asthmatics with a total dose of 7.6 g of www.microbiologyworld.com
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MSG. Upon observation, none of the non-asthmatics experienced any change in pulmonary reactions and only one asthmatic participant experienced some discomfort.
Chinese Restaurant Syndrome (CRS) In 1968, Robert Ho Man Kwok, M.D., described a collection of symptoms he allegedly experienced after eating Chinese food. He coined the phrase “Chinese Restaurant Syndrome” (CRS) to describe these symptoms, which included numbness at the back of the neck and a feeling of pressure in the face and upper chest muscles. As a consequence of Kwok’s account, Kerr and colleagues developed a subjective questionnaire to assess the prevalence of CRS in the population. The survey employed listed 18 adverse symptoms related to food, of which three were related to CRS. Of the 3,222 general households that responded to the survey, 43 percent reported food-related adverse reactions, but only 1.8 percent reported possible CRS symptoms. Richard Kenney, M.D., of George Washington University did a lot of experiments to evaluate the use of MSG and relation of CRS. He tested 60 people with He further tested 60 subjects with orange juice, spiced tomato juice, black coffee, flavored milk and a two percent MSG solution. Upon examining reactions, Kenney found that six subjects responded to coffee, six to spiced tomato juice and only two to the MSG solution, indicating that MSG was not unique in producing symptoms typical of CRS. However several people in many experimental studies have been seen showing some indications of CRS by the uptake of MSG. These include tightness in the chest, flushing and headache.
Conclusion MSG is one of the most intensely used food ingredient on today’s culinary world. Numerous researches have been conducted to see its adverse effects on human body and no concrete evidence has been found to say that MSG is bad for health in the regular amounts used by the common man. Chinese salt is safe to eat in a limit as it is mostly used. However excess of MSG may cause bad results on human health.
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Prions: The Killer Proteins Mr. Shaikh Rajesh Ali Assitant Professor, Dept. Of Microbiology, Acharya Prafulla Chandra College, New Barrackpore, Kolkata -700131 Introduction: Prions is an acronym for ‘proteinaceous infectious particles’. The term was coined in 1982 by Stanley B. Prusiner, a neurologist at the University of California at San Francisco, who proposed that a new type of pathogen consisting solely of protein is responsible for deadly neurodegenerative diseases called Transmissible Spongiform Encephalopathies (TSEs) and received the Nobel Prize in medicine in 1997 for his work on them. These include scrapie in sheep, bovine spongiform encephalopathy (BSE or ‘mad cow disease’) in cattle and CreutzfeldtJakob Disease (CJD) in people. Chemical Nature of prions: The chemical nature of the prions, as stated earlier, is considered to be proteinaceous and they have no nucleic acids of their own. This has been indicated by the various experimental evidences gathered so far. This aspect of prion has been investigated by treating them with nucleases (the enzymes that digest nucleic acids) and proteases (the enzymes that digest proteins). It has been observed that the nucleases have no effect of prion infectivity, whereas proteases can drastically reduce a prion infectivity. In addition, prions show high resistance to ionizing and ultraviolet radiations, which act mainly on nucleic acids.
Structure of Prions: Prion is 100 times smaller than a virus, contains only protein, are heterogenous in size and density, and can exist in many molecular forms. The protein that prions are made of (PrP) is found throughout the body, even in healthy people and animals. However, PrP found in infectious material has a different structure and is resistant to proteases, the enzymes in the body that can normally break down proteins. www.microbiologyworld.com
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The normal form of the protein is called PrPC, while the infectious form is called PrPSc — the C refers to 'cellular' or 'common' PrP, while the Sc refers to 'scrapie', a prion disease occurring in sheep. PrPC is a normal protein found on the membranes of cells. It has 209 amino acids (in humans), one disulfide bond, a molecular weight of 35-36 kDa and a mainly alphahelical structure. The infectious isoform of PrP, known as PrP Sc, is able to convert normal PrPC proteins into the infectious isoform by changing their conformation, or shape; this, in turn, alters the way the proteins interconnect. Although the exact 3D structure of PrP Sc is not known, it has a higher proportion of β-sheet structure in place of the normal α-helix structure. Aggregations of these abnormal isoforms form highly structured amyloid fibers, which accumulate to form plaques. Synthesis of prion: The prion is a product of a human gene, termed
the
PrP
gene,
found
on
chromosome 20. This gene contains two exons separated by a single intron. Exon I and Exon II are transcribed and the two RNAs ligated into a single mRNA. This mRNA contains an open reading frame (ORF) or protein coding region which is translated into the PrP protein. The PrP protein is a precursor of the prion protein. It is termed PrP 33-35.
The PrP 33-35 undergoes several post-translational events to become the prion protein (PrP 27-30): a) Glycosylation - at two sites. b) Formation of a disulfide bond between two cysteine residues. c) Removal of the N-terminal signal peptide. d) Removal of the C-terminal hydrophobic segment. www.microbiologyworld.com
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e) Addition of a phosphatidylinositol glycolipid at the C-terminal. f) Removal of the N-terminal first 57 amino acids.
In normal cells only the PrP 33-35 protein is synthesized. It is found in the neural cell membrane where it's function is to sequester Cu ++ ions. In abnormal ("infected") cells, the PrP 27-30 is produced from the PrP 33-35 protein. The PrP 27-30 triggers a series of reactions that produce more PrP 27-30 proteins, i.e., PrP 27-30 induces its own synthesis. In addition to the post translational modifications, the PrP 27-30 protein differs from the PrP 33-35 protein in a single amino acid residue. Residue 178 in the PrP 27-30 contains an asparagine residue whereas the PrP 33-35 protein has an aspartate residue at this position. This causes a conformational change in the PrP 27-30 protein from an a-helix to a b-sheet. This conformational change in the PrP 27-30 protein has three effects: a) It imparts to the PrP 27-30 protein the ability to induce the same a-helix to b-sheet conformation in the PrP 33-35 protein. This is a permanent conformational change. It thus induces its own "replication." b) The b-sheet-forming peptides aggregate to form amyloid fibrils. c) The amyloid fibrils kill thalamus neurons through apoptosis, a programmed series of events that leads to cell death. Prion replication mechanism: The hypothesis that tried to explain how prions replicate in a protein-only manner was the heterodimer model. This model assumed that a single PrP Sc molecule binds to a single PrP C
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molecule and catalyzes its conversion into PrP Sc. The two PrPSc molecules then come apart and can go on to convert more PrP C.
Transmission of prions: Spread of the disease is via horizontal transmission, i.e., transmission from one person to another, either directly or by fomites or by ingestion of contaminated meat. These diseases in humans are now grouped together according to whether they are sporadic, inherited, or acquired. Most cases of prion disease are sporadic; that is, they arise spontaneously for no known reason. More rarely prion disease is inherited due to a faulty gene, or acquired by medical procedures, transfusions, or contaminated food. Sporadic and inherited prion disease occurs worldwide in all populations. The incidence of sporadic CJD is around 1 per million of the population per annum; males and females are equally affected.
The incidence of the
various acquired prion diseases, however, is more localized to specific groups and populations. Prion pathway to brain: The pathway to the brain is a subject of significant research, but currently, no comprehensive answer exists. In TSE linked to consuming TSE-infected material, it is theorized that once prions are ingested, they are taken up by the lymphoid tissue that drains the gastrointestinal tract including Peyer's Patches and other nodes. Prions also have been found in tonsil, spleen and www.microbiologyworld.com
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appendix. From the lymphatic system, research suggests that prions replicate, access and move through the autonomic nervous system to the central nervous system. Once in the brain, the higher concentration of cellular prion protein speeds up the replication process. Prions also may enter lesions or wounds in the oral cavity and access the vagus nerve as a pathway to the brain. Recent laboratory research using fluorescent dye to "brand" scrapie proteins has tracked prions as they invade nerve cells and then travel along wire-like circuits to points of contact with other cells. This appears to be the way the prions that cause TSE invade nerve cells and are transported along neural circuits throughout the nervous system.
Diseases caused by prions:
Affected animal(s)
Disease
sheep, goat
Scrapie
cattle mink
Bovine spongiform encephalopathy (BSE), mad cow disease Transmissible mink encephalopathy (TME)
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Chronic wasting disease (CWD)
cat
Feline spongiform encephalopathy (FSE)
nyala, oryx, greater kudu
Exotic ungulate encephalopathy (EUE)
ostrich
Spongiform
encephalopathy
(Not been shown to be transmissible.) Creutzfeldt–Jakob disease (CJD) iatrogenic Creutzfeldt-Jakob disease (iCJD) variant Creutzfeldt-Jakob disease (vCJD)
human
familial Creutzfeldt-Jakob disease (fCJD) sporadic Creutzfeldt-Jakob disease (sCJD) Gerstmann–Sträussler–Scheinker syndrome (GSS) Fatal familial insomnia (FFI) Kuru
A survey of spongiform diseases:
Classic CJD or Creutzfeldt-Jakob disease (human) The most prevalent of the spongiform diseases Occurs spontaneously in 1 out of a million people 10% of cases are inherited mutations in the PRPN gene Usually strikes people age 50 to 75 Symptoms: dementia, muscle twitching, vision problems Fatal Familial Insomnia (human) All cases are inherited mutations in the PrP gene Usually strikes people age 36 to 61 www.microbiologyworld.com
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Disruption of sleep/wake cycle leads to coma, then death Scrapie (goats, sheep) Occurs as infection in genetically susceptible sheep There is no evidence of spread to humans BSE or Bovine Spongiform Encephalopathy (cattle) Also known as "Mad Cow Disease" because infected animals act strangely and can be aggressive Spread rapidly through Britain by rendering Chronic Wasting Disease (deer, elk) Infectious disease in wild deer and elk primarily in the western United States Drooling, difficulty swallowing, weight loss Kuru (human) Struck members of the Fore tribe in the 1950s and 1960s Muscle weakness, loss of coordination, tremors, inappropriate episodes of laughter or crying Transmitted by ritual cannibalism as part of funeral ceremonies
Diseases caused by prions are known as spongiform diseases, because the brain tissue in infected individuals is filled with holes, giving it a sponge-like appearance. Although prions are found throughout the brain, the symptoms of spongiform diseases vary according to the regions they are most concentrated in. There are currently no effective treatments for spongiform diseases and all are fatal.
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Treatments of prions: The mechanism of prion replication has implications for designing drugs. Since the incubation period of prion diseases is so long, an effective drug does not need to eliminate all prions, but simply needs to slow down the rate of exponential growth. Models predict that the most effective way to achieve this, using a drug with the lowest possible dose, is to find a drug that binds to fibril ends and blocks them from growing any further.
Advancements in computer modeling have allowed for scientists to identify compounds which can serve as a treatment for prion caused diseases, such as one compound found to bind a cavity in the PrPC and stabilize the conformation, reducing the amount of harmful PrP Sc. Recently, anti-prion antibodies capable of crossing the blood-brain-barrier and targeting cytosolic prion protein (an otherwise major obstacle in prion therapeutics) have been described. Possible immunotherapeutic strategies for prion disease a | Ablation of mature follicular dendritic cells (FDCs) delays the development of prion disease in mice. However, treatment with multiple doses of CpG-containing oligodeoxynucleotides
(CpG
ODNs)
produces severe unwanted side-effects, including necrosis
immunosuppression, and
liver
thrombocytopaenia. b |
Treatment with the lymphotoxin- receptor (LT- R)â&#x20AC;&#x201C;Ig fusion protein seems to be better tolerated, but the best protection is achieved when the fusion protein is administered immediately after exposure to prions. c | Vaccination against a selfprotein is difficult because of immune tolerance, and it has the potential to induce www.microbiologyworld.com
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autoimmune disease. Mice devoid of the prion protein (PrP) develop high PrP-specific antibody titres after immunization with PrP-derived peptides or full-length PrP; however, tolerance in wildtype mice allows the induction of only low titres of PrP-specific antibodies. d | Treatment with dimeric full-length PrP fused to the Fc portion of human IgG1 (PrPâ&#x20AC;&#x201C;Fc2) delays the development of prion disease in transgenic mice, most probably owing to its interaction with the diseaseassociated PrP (PrPSc). LT-
1
2,
LT heterotrimer; TLR, Toll-like receptor.
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Hybridoma Technology: A Tool in immunotherapy Nwabufo Chukwunonso Kingsley Department of Biochemistry, Faculty of life sciences, University of Benin, Benin city, Edo state, Nigeria. Corresponding Email: Nwabufokingsley@yahoo.com Abstract Hybridoma technology involves forming hybrid cell lines (called hybridomas) by fusing an antibody -producing B cell with a myeloma (B cell cancer) cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis. The antibodies produced by the hybridoma are all of a single specificity and are therefore monoclonal antibodies. These monoclonal antibody formed can be purified by antigen affinity chromatography. Considerable advancements in the last 10-15 years have been made to improve the quality and yield of monoclonal antibody by hybridoma technology such as the use of myelomas that do not secrete their own antibodies and that therefore do not interfere with the production of the required antibody. Immunotherapy is the "treatment of disease by inducing, enhancing or suppressing an immune response". The quest to develop advanced and effective diagnosis and treatment to certain disease conditions has led to advancement in immunotherapeutic procedures of which the use of hybridoma technology has widely been credited to. In this so-called Monoclonal antibody therapy, monoclonal antibody are targeted against specific antigen and thus enhances the ability of the immune system to suppress the antigen. Some of the targeted disease conditions in which monoclonal antibody therapy has widely been used include: cancer (Tositumomab
for
non-Hodgkins
lymphomas),
autoimmune
diseases
(Infliximab
and
Adalimumab which are effective in rheumatoid arthritis, crohn`s disease and uclerative Colitis. Keywords: Hybridoma technology, Monoclonal antibody, Immunotherapy, Monoclonal Antibody Therapy. www.microbiologyworld.com
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Introduction Hybridomas are cells that have been engineered to produce a desired antibody in large amounts, to produce monoclonal antibodies [1,2]. Monoclonal antibody can be produced by a technique called hybridoma technology. Hybridoma technology involves forming hybrid cell lines (called hybridomas) by fusing a specific antibody-producing B- cells with a myeloma(B- cell cancer) cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis. The antibodies produced by the hybridoma are all of single specificity and are therefore monoclonal antibody [2].
In 1975, Ce`sar Milstein and Georges J. F kohler invented the production of monoclonal antibodies and they shared the nobel prize of 1984 for medicine and physiology with Niels Kaj Jerne, who made other contributions to immunology. The term hybridoma was coined by Leonard Herzenberg during his sabbatical in CĂŠsar Milstein's laboratory in 1976/1977 [1]. Generally, the production of one MAb, using the hybridoma technology, costs between $8,000 and $12,000. The average reasonably SK can generate only 15 to 30 hybridoma fusions per year, but in an environment where the focus is on diagnostic- or therapeutic-quality MAbs, there are additional significant limitations than can further decrease throughput [3].
Passive immunity using monoclonal antibody is the largest category of biotechnology developed chemotherapy. In passive immunity, instead of injecting a specific antigen and inducing the body to produce an immune response (vaccination), a specific antibody targeted against an antigen is introduced into the body which enhances the ability of the immune system to suppress the antigen for example, administering multiple doses of HERCEPTIN, a monoclonal antibody against breast cancer to a patient diagnosed of breast cancer helps the immune system to suppress the growth of the cancer cell. This is the basis of the so-called "Monoclonal Antibody Therapy" which has revolutionalised immunotherapy. Methodology Laboratory animals usually mice or rat are injected with an immunizing dose of a specific antigen. Once the animal is making a good antibody response, the spleen is removed and a cell www.microbiologyworld.com
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suspension is prepared, lymph node cells may also be used. These cells are fused with a myeloma cell line by the addition of poly ethylene glycol which promotes membrane fusion. The myeloma cell is a B cell cancer cell and consequently can grow indefinitely. In addition, the myeloma cell is deficient in the enzyme HYPOXANTHINE GUANINE PHOSPHORIBOSYL TRANSFERASE (HPGRT).This is a key enzyme in the biosynthesis of purines and pyrimidines using the salvage pathway. This means that the myeloma cells can only use the De novo pathway to synthesize purines and pyrimidines but cannot use the salvage pathway. However, the spleen cells can use both the De novo and salvage pathway to synthesize purines and pyrimidines. Only small proportion of the cells fuse successfully. The Fusion mixture is then cultured in a medium containing HYPOXANTHINE, AMINOPTERIN AND THYMIDINE called a HAT - MEDIUM.
Aminopterin blocks De novo pathway of purine and pyrimidine synthesis. However this pathway can be bypassed in favour of the salvage pathway by the provision of hpoxanthine and thymidine in the HAT medium. The spleen cells can grow in the HAT medium using the salvage pathway but myeloma cells cannot grow in the HAT medium because they are incapable of using the salvage pathway due to the deficiency of the enzyme HPGRT. They therefore die in the HAT medium. When the culture was set up in the HAT-medium, it contains spleen cells, myeloma cells and fused cells. The unfused spleen cells die in culture naturally after 1-2 weeks. Unfused myeloma cells are killed by the HAT-medium but fused cells survive as they have the immortality of the myeloma and the ability of spleen cells to use the salvage pathway for purine and pyrimidine biosynthesis. Some of the fuse cells or hybridoma will also have the antibody producing capacity of the spleen cells.
Any wells containing growing cells are tested for the production of the desired antibody and if positive, the cultures are cloned, that is, plated out so that only one cell is in each well. This produces a clone of cells derived from a single progenitor which is both immortal and produces monoclonal antibody.
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Purification
of
Monoclonal
Antibodies Monoclonal antibodies may need to be purified before they are used for a variety of purposes. Before
final
purification,
the
cultures may be subjected to cell fractionation for enrichment of the antibody protein. In E. coli, the antibodies may be secreted in the periplasm, which may be used for enrichment of antibody, so that further purification is simplified.
Alternatively
the
antibodies may be purified from cell homogenate or cell debris obtained from the medium. (6, 7) Antibodies can be purified by anyone of the following techniques (I)
ion-exchange chromatography;
(II)
antigen affinity chromatography
Advancements in Hybridoma Technology Considerable efforts during the last 10-15 years have been made to improve the yield of monoclonal antibodies using hybridoma technology [4, 5]. These efforts include the following: (1) The substitution of a chemical fusion promoter (P.E.G.) for the Sendai virus initially used to promote fusion, and (2) The use of myelomas that do not secrete their own antibodies and that therefore do not interfere with the production of the required antibody
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(3) A continuous cell line (Sp 2/0) was used as a fusion partner for the antibody producing B cells. (4) Feeder layers consisting of extra cells to feed newly formed hybridomas were used for optimal growth and hybridoma production. Advancements OR Improvements in Hybridoma Technology – Considerable efforts during the last 10-15 years have been made to improve the yield of monoclonal antibodies using hybridoma technology. The most common feeder layers consist of: • murine peritoneal cells, • marcrophages derived from mouse, rat or guinea pig • extra non immunized spleen cells, • human fibroblasts, human peripheral blood monocytes or thymus cells; these feeder cells had some limitations like depletion of nutrients meant for hybridoma and contamination, so that other sources of hybridoma growth factors (HGF) like interleukin-6 (II-6) derived from human cells were used. Application of Hybridoma Technology in Immunotherapy The production of monoclonal antibody by hybridoma technology makes this technology an indispensable tool in immunotherapy. The quest to develop advanced and effective diagnosis and treatment to certain disease conditions has led to advancement in immunotherapeutic procedures of which the use of hybridoma technology has widely been credited to.
Immunotherapy is the "treatment of disease by inducing, enhancing, or suppressing an immune response" [8]. Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies, while immunotherapy’s that reduce or suppress are classified as suppression immunotherapy’s [9]. There are several types of immunotherapy’s including, monoclonal antibody, and nonspecific immunotherapy and Cancer vaccines [9]. We shall look at applications of monoclonal antibody in immunotherapy. Immunotherapy developed as a technique with the discovery of the structure of antibodies and the development of hybridoma technology, which provided the first reliable source of monoclonal antibodies, and allowed therapeutic development since the 1970s [10, 11]. These advances allowed for the specific www.microbiologyworld.com
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targeting of tumors both in vitro and in vivo. Initial research on malignant neoplasms found MAb therapy of limited and generally short-lived success with malignancies of the blood [12, 13]. Furthermore treatment had to be specifically tailored to each individual patient, thus proving to be impracticable for the routine clinical setting. Throughout the progression of monoclonal drug development there have been four major antibody types developed: murine, chimeric, humanized and human [9].
Initial therapeutic antibodies were simple murine analogues, which contributed to the early lack of success. It has since been shown that these antibodies have: a short half-life in vivo (due to immune complex formation), limited penetration into tumour sites, and that they inadequately recruit host effectors functions [14]. To overcome these difficulties the technical issues initially experienced had to be surpassed. Chimeric and humanized antibodies have generally replaced murine antibodies in modern therapeutic antibody applications. Hybridoma technology has been replaced by recombinant DNA technology, transgenic mice and phage display [15]. Understanding of proteomics has proven essential in identifying novel tumour targets. Some of the targeted disease disease conditions in which monoclonal antibody therapy has widely been used include: Cancer Anti-cancer monoclonal antibodies can be targeted against malignant cells by several mechanisms: Radioimmunotherapy (RIT) involves the use of radioactively conjugated murine antibodies against cellular antigens. Most research currently involved their application to lymphomas, as these are highly radio-sensitive malignancies. To limit radiation exposure, murine antibodies were especially chosen, as their high immunogenicity promotes rapid clearance from the body. Tositumomab is an example used for non-Hodgkins lymphoma. Antibody-directed enzyme prodrug therapy (ADEPT) involves the application of cancer associated monoclonal antibodies which are linked to a drug-activating enzyme. Subsequent systemic administration of a non-toxic agent results in its conversion to a toxic drug, and resulting in a cytotoxic effect which can be targeted at malignant cells. The clinical success of www.microbiologyworld.com
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ADEPT treatments has been limited to date [16]. However it holds great promise, and recent reports suggest that it will have a role in future oncological treatment. Immunoliposomes are antibody-conjugated liposomes. Liposomes can carry drugs or therapeutic nucleotides and when conjugated with monoclonal antibodies, may be directed against malignant cells. Although this technique is still in its infancy, significant advances have been made. Immunoliposomes have been successfully used in vivo to achieve targeted delivery of tumour-suppressing genes into tumours, using an antibody fragment against the human transferrin receptor. Tissue-specific gene delivery using immunoliposomes has also been achieved in brain, and breast cancer tissue [17].
Fig. 2: Monoclonal antibodies for cancer. ADEPT, antibody directed enzyme prodrug therapy; ADCC, antibody dependent cell-mediated cytotoxicity; CDC, complement dependent cytotoxicity; MAb, monoclonal antibody; scFv, single-chain Fv fragment [18].
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Autoimmune diseases Monoclonal antibodies used for autoimmune diseases include infliximab and adalimumab, which are effective in rheumatoid arthritis, Crohn's disease and ulcerative Colitis by their ability to bind to and inhibit TNF-α [19]. Basiliximab and daclizumab inhibit IL-2 on activated T cells and thereby help preventing acute rejection of kidney transplants [19]. Omalizumab inhibits human immunoglobulin E (IgE) and is useful in moderate-to-severe allergic asthma. Conclusion The limitation in the production of monoclonal antibody by hybridoma technology opened doors for improvements. This advancement in hybridoma technology led to an appreciable increase in the quality and quantity of monoclonal antibody produced hybridoma technology. These monoclonal
antibodies
are
essential
tools
in
biochemical
research,
Diagnosis,
immunopurification and immunotherapy. With recent outbreak of Ebola virus infection, much research should be carried out towards the efficacious treatment of this infection using monoclonal antibody which will further highlight the so-called Monoclonal Antibody Therapy. References 1. Bretton, PR, Melamed, MR, Fair, WR, Cote, RJ (1994). Detection of occult micrometastases in the bone marrow of patients with prostate carcinoma. Prostate. 25(2), 108-14. 2. http://en.wikipedia.org/wiki/Hybridoma_technology #Method 3. Franklin, WA, Shpall, EJ, Archer, P, Johnston, CS, Garza-Williams, S, Hami, L, Bitter MA, Bast RC, Jones, RB (1996). Immunocytochemical detection of breast cancer cells in marrow and peripheral blood of patients undergoing high dose chemotherapy with autologous stem cell support. Breast Cancer Res Treat. 41(1), 1-13. 4. Ghosh,
AK,
Spriggs,
Al,
Taylor-papadimitriou,
J
and
Mason,
DY
(1983).
Immunocytochemical staining of cells in pleural and peritoneal effusions with a panel of monoclonal antibodies. J Clin Pathol, 36, 11541164. 5. Kvalheim, G (1996). Detection of occult tumour cells in bone marrow and blood in breast cancer patients—methods and clinical significance. Acta Oncol, 35, 13-8.
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6. http://www.molecular-plant-biotechnology.info/hybri doma-and-monoclonal-antibodies-mabs/ raising-theantibodies.htm 7. Elements of biotechnology, P.K. GUPTA (1st EDITION): 2006-2007, (203-211). 8. ^ "immunotherapies definition”. Dictionary.com. Retrieved 2009-06-02 9. http://en.m.wikipedia.org/wiki/Monoclonal_antibody_therapy 10. Prof
FC
Breedveld
(2000).
"Therapeutic
monoclonal
antibodies"
Lancet.
doi
:10.1016/S0140-6736(00)01034-5 . 11. Köhler G, Milstein C (August 1975). "Continuous cultures of fused cells secreting antibody of predefined specificity". Nature 256 (5517): 495–7. Bibcode: 1975 Natur.256..495K. doi: 10.1038/256495a0. PMID 1172191. 12. Nadler LM, Stashenko P, Hardy R, et al. (September 1980). "Serotherapy of a patient with a monoclonal antibody directed against a human lymphoma-associated antigen". Cancer Res. 40 (9): 3147–54. PMID 7427932. 13. Ritz J, Schlossman SF (January 1982). "Utilization of monoclonal antibodies in the treatment of leukemia and lymphoma". Blood 59 (1): 1–11. PMID 7032624. 14. a b c Stern M, Herrmann R (April 2005). "Overview of monoclonal antibodies in cancer therapy: present and promise". Crit. Rev. Oncol. Hematol. 54 (1): 11–29. doi :10.1016/j.critrevonc.2004.10.011 . PMID 15780905. 15. a b Hudson PJ, Souriau C (January 2003). "Engineered antibodies". Nat. Med. 9 (1): 129– 34. doi: 10.1038/nm0103-129 .PMID 12514726. 16. Francis RJ, Sharma SK, Springer C, et al. (2002). "A phase I trialof antibody directed enzyme prodrug therapy (ADEPT) in patientswith advanced colorectal carcinoma or other CEA producingtumours. Br J Cancer 87 (6): 600–7. doi :10.1038/sj.bjc.6600517 .PMC 2364249 . PMID 12237768. 17. Krauss WC, Park JW, Kirpotin DB, Hong K, Benz CC (2000). "Emerging antibody-based HER2 (ErbB-2/neu) therapeutics". BreastDis 11: 113–124. PMID 15687597. 18. Modified from Carter P (November 2001). "Improving the efficacy of antibody-based cancer therapies". Nat. Rev. Cancer 1 (2): 118–29. doi : 10.1038/35101072 . PMID 11905803. 19. a b Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. p. 241. ISBN 0443-07145-4. www.microbiologyworld.com
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Lyophilisation: A Method of Preserving Biologicals Dr Sakshi Bhadouriya, M.V.Sc (Vet. Virology, IVRI, Bareilly) Dr Sunil Singh Tomar, M.V.Sc (Vet. Clinical Medicine) Introduction Lyophilisation (also known as Freeze Drying or Cryodesiccation) is a dehydration process typically used to preserve a perishable material or make the material more convenient for transport. With proper packaging and storage, freeze-dried products can be stored for a very long time without any appreciable loss of quality even at room temperature. Freeze-drying works by freezing the material and then reducing the surrounding pressure and adding enough heat to allow the frozen water in the material to sublime directly from the solid phase to the gas phase. Lyophilisation technology is used to freeze-dry products such as biologicals, bacterial cultures, analytical chemistry moieties, and therapeutic molecules (e.g., antibodies, vaccines, drugs, and heat-sensitive proteins). Lyophilizing such products, particularly liquid formulations, vastly increases their shelf-life and stability. Freeze-dried products have an optimal capacity to take up water again (reconstitution, rehydration). The Principles of Freeze-Drying At atmospheric pressure (approx. 1,000 mbar) water can have three physical states: 1.
Solid;
2.
Liquid;
3. Gaseous. Below the triple-point (for pure water at 0°C), only the solid and the gaseous states exists. The principle of freeze/sublimation-drying is based on this physical fact. The ice in the product is directly converted into water vapour without passing through the “fluid state”.
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Process of Freeze Drying The process consists of three separate, unique, and interdependent processes:
Freezing
Primary drying (sublimation),
Secondary drying (desorption).
In a lab, this is often done by placing the material in a freeze-drying flask and rotating the flask in a bath, called a shell freezer, which is cooled by mechanical refrigeration, dry ice and methanol, or liquid nitrogen. On a larger scale, freezing is usually done using a freeze-drying machine. In this step, it is important to cool the material below its triple point, the lowest temperature at which the solid and liquid phases of the material can coexist. This ensures that sublimation rather than melting will occur in the following steps. Larger crystals are easier to freeze-dry. To produce larger crystals, the product should be frozen slowly or can be cycled up and down in temperature. This cycling process is called annealing. However, in the case of www.microbiologyworld.com
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food, or objects with formerly-living cells, large ice crystals will break the cell walls (a problem discovered, and solved, by Clarence Birdseye), resulting in cell destruction, and, in the case of rehydrated foods, a poor texture. In this case, the freezing is done rapidly, in order to lower the material to below its eutectic point quickly, thus avoiding the formation of ice crystals. Usually, the freezing temperatures are between −50 °C and −80 °C. The freezing phase is the most critical in the whole freeze-drying process, because the product can be spoiled if badly done. Amorphous materials do not have a eutectic point, but they do have a critical point, below which the product must be maintained to prevent melt-back or collapse during primary and secondary drying. Primary Drying During the primary drying phase, the pressure is lowered (to the range of a few millibars), and enough heat is supplied to the material for the water to sublimate. The amount of heat necessary can be calculated using the sublimating molecules’ latent heat of sublimation. In this initial drying phase, about 95% of the water in the material is sublimated. This phase may be slow (can be several days in the industry), because, if too much heat is added, the material’s structure could be altered. In this phase, pressure is controlled through the application of partial vacuum. The vacuum speeds sublimation, making it useful as a deliberate drying process. Furthermore, a cold condenser chamber and/or condenser plates provide a surface(s) for the water vapour to re-solidify on. This condenser plays no role in keeping the material frozen; rather, it prevents water vapor from reaching the vacuum pump, which could degrade the pump's performance. Condenser temperatures are typically below −50 °C (−60 °F). It is important to note that, in this range of pressure, the heat is brought mainly by conduction or radiation; the convection effect is considered to be inefficient. Secondary drying The secondary drying phase aims to remove unfrozen water molecules, since the ice was removed in the primary drying phase. This part of the freeze-drying process is governed by the material’s adsorption isotherms. In this phase, the temperature is raised higher than in the primary drying phase, and can even be above 0 °C, to break any physico-chemical interactions www.microbiologyworld.com
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that have formed between the water molecules and the frozen material. Usually the pressure is also lowered in this stage to encourage desorption (typically in the range of microbars, or fractions of a pascal). However, there are products that benefit from increased pressure as well. After the freeze-drying process is complete, the vaccum is usually broken with an inert gas, such as nitrogen, before the material is sealed. At the end of the operation, the final residual water content in the product is extremely low, around 1-4%. Flow Chart of Lyophilisation Material in vial in shelves is pre-chilled the shelves to -45 c & initiate the drying when material temp -40 c.
Vaccine harvest + stabiliser
Product in direct contact vd shelves (-40 c)
Condenser temp (-55 to -60 c)
Then primary drying starts (1% to 4%)
Remove crystalline ice by sublimation when water sublimes it takes energy so product is cooled
Energy of sublimated water is release to condenser so condenser tends to warm
Self heating & refrigeration & compressor works counteractly.
Product have residual 5-10 % moisture (not frozen so all ice is removed in this) Key Component of Freeze Drying ď&#x201A;ˇ
Vaccum chamber
ď&#x201A;ˇ
Lyophilisation shelves
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Heat transfer fluid
Product
Condenser
A mechanical or cryogenic refrigeration system
Heater
Vaccum pump
Control hardware and software
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Freeze Drying Methods Three methods of Freeze Drying are commonly used: 1. Manifold drying 2. Batch drying 3. Bulk Drying Properties of freeze-dried products If a freeze-dried substance is sealed to prevent the reabsorption of moisture, the substance may be stored at room temperature without refrigeration, and be protected against spoilage for many years. Preservation is possible because the greatly reduced water content inhibits the action of microorganisms and enzymes that would normally spoil or degrade the substance. Freezedrying also causes less damage to the substance than other dehydration methods using higher temperatures. Freeze-drying does not usually cause shrinkage or toughening of the material being dried. Freeze-dried products can be rehydrated (reconstituted) much more quickly and easily because the process leaves microscopic pores. The pores are created by the ice crystals that sublimate, leaving gaps or pores in their place. This is especially important when it comes to pharmaceutical uses. Freeze-drying can also be used to increase the shelf life of some pharmaceuticals for many years
Disadvantages of Freeze Drying
Maintaining frozen storage is costly and takes up a lot of space
Transportation of frozen materials can be difficult and expensive
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Failure of freezing equipment would risk the total loss of the product
Conventional drying methods also have a major disadvantage as the high temperatures used can cause chemical or physical changes to the product.
References 1. LYOPHILIZATION: Univ.Prof. Eng. Dumitru MNERIE, PhD “POLITEHNICA” University of Timisoara ROMANIA 2. T. A. Jennings, “Lyophilization - Introduction and Basic Principles”, Interpharm Press, Buffalo Grove, IL 1999. 3. A. I. Liapis and R. Bruttini, in A.S. Mujumdar ed., “Handbook of industrial Drying” vol.1, 2nd ed., Marcel Dekker, New York and Basel, 1995, 309 – 343.
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Rapid diagnosis of acute respiratory infections by multiplex endpoint PCR technology 1
Aurelian Udristioiu, 2Manole Cojocaru, 3Dana Alexandra Maria Panait, 4Nica Badea Delia
1
Clinical Laboratory, Department of Hematology, Emergency County Hospital Targu Jiu & UCB University, Romania, E-mail: aurelianu2007@yahoo.com 2
Titu Maiorescu University, Faculty of Medicine, Physiology Department, Bucharest, Romania; E-mail: mancojocaru@yahoo.com
3
Titu Maiorescu University, Faculty of Medicine, Microbiology Department, Bucharest, Romania, E-mail dana2pan@yahoo.com
4
Constantin Brancusi University, Faculty of Medical Science and Behavioral, Targu Jiu, Romania, Email: nicabadeadelia@yahoo.com
Introduction The multiplex endpoint PCR technology offers a number of potential advantages, results are available in a matter of hours rather than days, the extreme sensibility facilitates detection of even minutes the amounts of pathogen DNA in clinical samples and the test is not significantly affected by prior administration of antibiotics. Aim The aim of this work was to rapidly identify the antibiotic resistance the monitoring of pathogen growth at the patients admitted in Hospitalization Intensive Care Unit of Emergency County Hospital Targu Jiu with the diagnosis of Community Acquired Pneumonia, (CAP), in months December/2013-March/2014. Method The Analyzer Unyvero™ Pneumonia Application was used in detection of pneumonia associated pathogens and their antibiotic resistance genes using the Pneumonia Unyvero™ System, following PCR pathogen species with sequencing of the amplified microbial DNA. www.microbiologyworld.com
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Results The main pathogens of community acquired pneumonia from the cohort study, 36 cases, (20 males in mean age 35-66
years and 16 females in mean age 40-55 mean years) were
Streptococcus pneumonia (16 cases), Staphilococcus aureus, (10 cases),
Klebsiella
pneumonia (5 cases), and other important agents were “atypical”, such as Haemophilus Influenzae, Chlamidophila pneumonie and Moraxela cataralis.
A case with Acinetobacter baumani and Proteus Sp. was also widely resistance to mefA gene / ermB gene as all cases of analyzed. The more frequency of genes resistant (29 cases) are ermA gene / ermC / ermB for Staphilococcus aureus and the gene tem+shv / gene / ctx-M with the chromosomal mutation (7 cases), as gyrA83_87 Ecoli / Pseu for Klebsiella pneumonia agents. Also most resistance antibiotics were Makrolides, (29 cases and Lincosamides (6 cases) and this cases have had the chromosomial integrates. The most resistance microbe, Pseudomonas aeruginosa (1 case), has been registered as multi drugs resistance [MDR]*.
Fig. 1: Microorganism results in Pneumonia Panel www.microbiologyworld.com
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No. Microorganisms Antibiotic resistance IDL detected 1310_1 Klebsiella pneumonia Makrolides /], [ermB],].Lincosamides
Gene resistance
1310_2 Streptoccocus Sp.
ermB gene/tem gene
ermB gene
Makrolides.
1310_3 Staphilococcus Penicilins (tem) aureus Other/Fungi: Chlamidophila pneumonie 1310_4 Klebsiella pneumonia Makrolides / Lincosamides
ermB gene/tem gene Chromosomal mutation; Pseud. aeruginosa, (gyrA83Ecoli
1310_5 Proteus Sp. Other/Fungi: Haemophilus Influenzae, Chlamidophila pneumonie 1311_1 Streptococcus pneumonia Moraxela cataralis
Makrolides Oxacilin
ermB gene/oxa51 Chromosomal mutation; Escherichia Coli (gyrA8387_Ecoli ).
Makrolides, Oxacillin Lincosamides,
ermB gene/tem gene/ mecA gene
1311_2 Streptococcus pneumonia
Makrolides / [mefA], [ermB],].Lincosamides Penicilins (tem)
mefA gene / ermB gene / tem
1311_3 Streptococcus pneumonia Pseudomonas aeruginosa
Makrolides / [mefA], [ermB],].Lincosamides [MDR]* [int1].
mefA gene / ermB gene [int1gene].
1311_4 Klebsiella pneumonia Penicilins (shv)
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ermB gene
mefA gene / shv gene [int1gene] /sul 1 gene Chromosomal mutation; (gyrA83_3Pseu).
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Makrolides / [mefA], [ermB],].Lincosamides
1312_1 Staphilococcus Makrolides / [mefA], aureus [ermB],].Lincosamides Klebsiella pneumonia 3rd Gen Cephalosporins [tem+shv], [ctx-M].
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mefA gene / ermB gene
ermA gene / ermC / ermB tem+shv / gene / ctx-M g Chromosomal mutation; gyrA83_87 Ecoli / Pseu
[MDR]*-Multi drugs resistance Table 1. Resistance markers of the Pneumonia panel and the resulting antibiotic resistances
Photo 1. Analyzer Unyvero™ Pneumonia
Conclusion The Unyvero™ results have been available 2 days before the primary microbiology report and 3 days before the final confirmation results, obtained by microbiology culture. The Unyvero Analyzer only provides rapid data to support the therapeutic decision of currant medic.
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Bioweapons: A new trend in emerging Sciences 1
Hasnain Nangyal, 2Noor Nasir Khattak, 3Sikander Khan Sherwani
1
Department of Botany, Hazara University, Khyber Pakhtoonkhwa, Pakistan
2
Department of Gynocology and Obteristics, Kohat Medical College, Khyber Pakhtoonkhwa, Pakistan 3
Department of Microbiology, FUUAST, Karachi, Pakistan Corresponding Author Email: hasnain308@yahoo.com
Basically different biologists defined this term in different ways: 1. Bioweapons are the biological agents derived from the living organisms that are capable of infecting and causing both sickness and death in people, animals and plants. 2. Bioweapons sometime called biowarfare which means that intentional use of microorganisms or toxins derived from living organisms of as an act of war or political violence with intent to cause death or disease in human, animal or in plants (1) 3. Biological warfare (BW)â&#x20AC;&#x201D;also called germ warfare. It is the use of biological toxins or infectious agents such as bacteria, viruses, and fungi with intent to kill or incapacitate humans, animals or plants as an act of war. 4. Biological weapons (often termed "bio-weapons", "biological threat agents", or "bioagents") are living organisms or replicating entities (viruses, which are not universally considered "alive") that reproduce or replicate within their host victims. 5. Biological warfare agents are likely to be selected for their ability to either incapitate or kill human targets of attack. Types of Bioweapons: There are seven types of biological agents: 1: Parasites 2: Fungi and yeasts 3: Bacteria 4: Rickettsia and chlamydia www.microbiologyworld.com
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5: viruses 6: Prions 7: Toxins 8: Insects
Among the biological agent only bacteria, viruses and toxins are considered when referring to agents that can be used in a biological attack. While toxins are included in the list of biological agents, they are not living organisms, but small proteins produced by bacteria that can poison to a person, animal or plant. Bacteria, viruses and toxins can be spread through the contamination of food, water or fomites; via vectors such as insects; or as aerosols suspended in wet or dry formulations (2).
Entomological (insect) warfare is also considered a type of biological weapon. This type of warfare is distinct from nuclear warfare and chemical warfare. None of these falls under the term conventional weapons which are primarily effective due to their destructive potential. Biological weapons (BWs) deliver toxins and microorganisms, such as viruses and bacteria, so as to deliberately inflict disease among people, animals, and agriculture. Biological attacks can result in destruction of crops, temporarily discomforting a small community, killing large numbers of people, or other outcomes.
Possible Biological Warfare Agents Bacteria (examples)
Viruses (examples)
Toxins (examples)
Bacillus anthracis (anthrax)
Variola virus (smallpox)
Staphylococcal enterotoxin B
Yersinia pestis (plague)
Equine encephalitis viruses (viral Ricin equine encephalitides)
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tularensis Arenaviruses,bunyaviruses, filoviruses
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Botulinum toxins
Brucella species (brucellosis) flaviviruses (hemorrhagic fevers)
Trichothecene mycotoxins
Coxiella burnetii (Q fever)
Saxitoxin
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Classification of Bioweapons: There are four classifications for how biological agents can be used to harm or kill a person, animal or plant. 1: Biological Warfare (BW): is the military use of biological agents, where targets of agents are predominately soldiers, governments, or resources that might hinder a nationâ&#x20AC;&#x2122;s ability to attack and/or defend it. 2: Bioterrorism (BT): is the threat or use of biological agents that, like most forms of terrorism, is intended to make political, religious or personal statements to governments and populations through attacks primarily aimed at civilians or resources that affect the civilian economy. With few exceptions, bioterrorism is non-state sponsored. 3: Biocrime (BC): is the threat or use of biological agents for individual objectives such as revenge or financial gain. 4: Bioaccident (BA): It is defined as the unintentional release of an agent from a laboratory or other facility. Biocrimes and Bioaccidents comprise events that typically have small effects on populations and do not require specific plans for large-scale preparedness and response (3). Categories of Bioweapons: The Critical Agent List classifies a relatively short list of possible biological weapons to be used in either biological warfare or bioterrorism, and was created by the Centers for Disease Control and Prevention (CDC) in conjunction with military, intelligence, medical and public health agencies: (20) Category A includes the highest priority agents because they are most likely to cause mass casualties, create panic and require a specific public health response. According to intelligence www.microbiologyworld.com
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sources, these are the agents that are most likely to be used in a future attack, and are being researched and weaponized by biowarfare programs around the world. Category B is the second highest priority agents, including those agents that could contaminate food or water, are relatively easy to disseminate, and require enhanced disease surveillance and diagnostic capacity. Many of these agents, such as brucellosis, glanders and ricin, were either weaponized by state-sponsored programs in the past, or utilized successfully in biological warfare or terrorist incidents Category C includes emerging pathogens that could be weaponized in the future because of the relative ease of accessing, producing and disseminating the agents, as well as the high levels of morbidity and mortality these agents would cause.(4) Although the CDC has been able to categorize a list of agents that are likely to be used as bioweapons, there are additional diseases and variations of biological agents that are of great concern. The Critical Agent List specifies only twenty-one diseases, but there are at least seventy different types of biological agents that can be weaponized, not including agents that do not already exist in nature. Of the disease caused by these seventy agents, only 20-30% is currently treatable through reliable methods.(5) Critical list of Biological agents Category A
Category B
Category C
Small pox
Q-fever
nipah virus
Anthrax
Brucellosis
Hantavirus
Plague
Glanders
multidrug-resistant TB
Tularemia
melioidosis
hemorrhagic fever
viral encephalitis
Ebola
Ricin
(21) History There is a long history of nations and peoples using biological agents as weapons. Many examples of use have been cited from as long ago as 190 BC, where Hannibal used venomous snakes to disrupt the enemy ships of Pergamus in Eurymedon. Biological weapons have a long www.microbiologyworld.com www.facebook.com/MicrobiologyWorld
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history of use. In 1346, the invading Tartar army catapulted the bodies of plague victims into the Crimean Peninsula city of Kaffa and infected its citizens. Another example of biological warfare often referred to in the historical record is the use of smallpox during the French and Indian War in 1763. Through the combined ingenuity of British Officers Sir Jeffrey Amherst and Colonel Henry Bouquet, smallpox infested blankets were given to the Indians at Fort Pitt, setting off an epidemic of smallpox that rendered the Indian tribes incapable of fighting off the British settlers (6). In this instance, it is not clear if the blankets themselves caused the outbreak of smallpox or whether it was due to previous exposure to the Europeans.
Regardless, this method of
biological warfare was used again during the American Civil War, when Dr. Luke Blackburn of Kentucky sold smallpox and yellow fever infected clothing to Union troops in an effort to support the efforts of the Confederacy. There were also reports that the Germans used plague against the Russians in 1915, and attempted to use cholera against Italy (7). Between 1933 and the late 1940â&#x20AC;&#x2122;s, Japan researched biological warfare at a compound known as Unit 731, where over 10,000 prisoners of war used for research purposes died of anthrax, meningitis, cholera and plague. Japan followed its experiments with prisoners of war by using biological agents against the people of China, causing outbreaks of typhus, cholera and plague, resulting in the deaths of tens of thousands of Chinese civilians.(19) One method used by the Japanese in Manchuria was dropping rice and plague infected fleas out of airplanes. The rice attracted rats, which then became infected with the fleas, thus creating efficient epidemiologic conditions by which the disease spread to humans over a large geographic area(8). The 2001 anthrax letter attacks in the United States infected 22 people and killed five (Biological weapon technology, 1998).The Genoese forces retreated back to Genoa, Venice and other Mediterranean ports, sparking the second wave of the plague epidemic in Europe. (9) Characterizing the Threat of Biological Weapons On 11 September 2001, terrorists used hijacked passenger planes loaded with jet fuel as explosion devices at the Pentagon and World Trade Center, killing approximately 3000. This attack awakened the American public to the idea that terrorists have the will and the means of inflicting harm on citizens of the United States within their national borders. Following the September 11th attack, letters with anthrax were mailed to a targeted list of media and political www.microbiologyworld.com
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There are many reasons why biological agents are effective means of
spreading terror which include followings;
Availability Biological agents are often simpler to acquire and produce than nuclear, chemical or some conventional weapons. The material for biological agents can be easily grown or purchased. Some agents, such as anthrax or brucellosis, occur naturally in animals in certain parts of the world, and individuals can easily travel the globe to acquire biological agents from regions where such diseases occur naturally. For example, the Aum Shinrikyo cult was reported to have gone to Zaire to collect strains of Ebola for use in its bioweapons program. Until recently, anyone could order agents from supply houses around the world (10). Access to Technology Technological advances over the last two decades in the field of biology have made it easier to produce biological weapons. Techniques once considered beyond the capacity of scientists are now commonplace, particularly in the field of genetic engineering. Bioengineers are now armed with the knowledge needed to create antibiotic resistant strains of agents, combine aspects of two agents, weaponize agents, and possibly target particular populations.
The creation of
antibiotic resistant strains of anthrax was a key component of the Soviet biowarfare program28. The Soviets were also successful in creating more virulent strains of the disease, capable of bypassing the available anthrax vaccine currently given to United States active duty forces29. Bioengineers are also now able to combine two agents to complicate the presentation of a disease in humans. Again, it was the Soviets who first used this technology by using recombinant DNA to combine features of smallpox and Ebola, and in 1995, Russian scientists presenting at a scientific conference in England, reported that they had combined a food poisoning organism with anthrax (11). Access to Information Information on how to create sophisticated biological weapons can be taken from articles published in the scientific literature on a variety of topics, but it requires a trained scientist to www.microbiologyworld.com
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understand the relevance of published findings to the creation of weapons.
However,
information on how to weaponize simpler biological agents is widely available and understandable to people with limited technological training. Lethality Biological agents can be extremely lethal, with some agents creating much more deadly affects than others. According to the Department of Defense, ten kilograms of anthrax could cause more casualties that a 10- kiloton nuclear weapon (12). Lack of Collateral Damage While biological agents may indiscriminately kill or injure humans, animals and plants, they do not destroy structures. This aspect of biological agents may be of interest to groups who desire to kill residents of an area, but protect surrounding assets, such as religious shrines, historical buildings, or industrial plants (13). Plague as a past bioweapon: Plague is a zoonotic disease caused by the bacterium Yersinia pestis, typically harbored by wild rodents (Fig). The plague epidemic that swept through Europe, the Near East, and North Africa in the mid-14th century was probably the public health disaster in recorded history. An estimated one-quarter to one-third of Europeâ&#x20AC;&#x2122;s population died from plague during the 14th century pandemic, and North Africa, the Near East, and perhaps the Far East had similar high levels of mortality.(14) However, the first recorded plague andemic began in 541 in Egypt when the world population as considerably smaller and decimated an even greater ercentage of the population. Advantages and Disadvantages of Biological Weapons Advantages 1: The potential deadly or incapacitating effects on a susceptible population 2: The self-replicating capacity of some biological agents to continue proliferating in the affected individual and potentially in the local population and surroundings www.microbiologyworld.com
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3: The relatively low cost of producing many biological weapons 4: The insidious symptoms that can mimic endemic diseases 5: The difficulty of immediately detecting the use of a biological agent, owing to the current limitations in fielding a multi-agent sensor system on the battlefield, as well as to the prolonged incubation period preceding onset of illness (or the slow onset of symptoms) with some biological agents(15) 6: The sparing of property and physical surroundings (compared with conventional or nuclear weapons)
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Disadvantages 1: The danger that biological agents can also affect the health of the aggressor forces 2: The dependence on prevailing winds and other weather conditions on effective dispersion 3: The effects of temperature, sunlight, and desiccation on the survivability of some infectious organisms 4: The environmental persistence of some agents, such as spore-forming anthrax bacteria, which can make an area uninhabitable for long periods 5: The possibility that secondary aerosols of the agent will be generated as the aggressor moves through an area already attacked 6: The unpredictability of morbidity secondary to a biological attack, since casualties (including civilians) will be related to the quantity and the manner of exposure 7: The relatively long incubation period for many agents, a factor that may limit their tactical usefulness 8: The public’s aversion to the use of biological warfare agents (16)
Indications of Possible Biowarfare Attack • A disease entity that is unusual or that does not occur naturally in a given geographic area, or combinations of unusual disease entities in the same patient populations • Multiple disease entities in the same patients, indicating that mixed agents have been used in the attack • Large numbers of both military and civilian casualties when such populations inhabit the same area • Data suggesting a massive point-source outbreak • Apparent aerosol route of infection • High morbidity and mortality relative to the number of personnel at risk • Illness limited to fairly localized or circumscribed geographical areas • Low attack rates in personnel who work in areas with filtered air supplies or closed ventilation systems • Sentinel dead animals of multiple species
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• Absence of a competent natural vector in the area of outbreak (for a biological agent that is vector-borne in nature) (17).
References: 1. Manchee R, Stewart W.1988. The decontamination of Gruinard Island. Chem Br.690– 691. 2. Nally R. E, Morrison MB, Stark M. 1993. Effectiveness of medical defense interventions against predicted battle field levels of Bacillus anthracis. Science Applications International.32-35 3. Patrick
W.C.1992.
Overview
of
biological
warfare.
Frederick,
Unpublished
manuscript.11-14 4. North Atlantic Treaty Organization. NATO Handbook on the Medical Aspects of NBC Defensive Operations. A-Med-P6, part 2, Biological. June 1992. 5. World Health Organization. Health Aspects of Chemical and Biological Weapons: Report of a WHO Group of Consult- ants . Geneva, Switzerland: WHO; 1970. 6. Huxsoll D, Patrick W.C, Parrott C.1987. Veterinary services in biological disasters. Journal of veterinary sciences. 714–722. 7. Department of the Army. Special Report to Congress. US Army Activities in the US Biological Defense Programs,1942–1977. Vols 1 and 2. Washington, DC: DA. 24 Feb 1977. Unclassified. 8. Special Subcommittee on the National Science Foundation of the Committee on Labor and Public Welfare, US.Senate. Chemical and Biological Weapons: Some Possible Approaches for Lessening the Threat and Danger. Washing-ton, DC: US Government Printing Office; May 1969. 9. Special Subcommittee on the National Science Foundation, Committee on Labor and Public Welfare. Chemical and Biological Weapons. Washington, DC: US Government Printing Office; May 1969. 10. Ursano R. Combat stress in the chemical and biological warfare environment. Aviation Space & EnvironmentalMedicine. 1988;59(12):1123–1124.
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11. Mojecki, J.A.1994. Mission-essential training and weapons of mass destruction. Military Review. 91–93. 12. Geissler E, ed.1986. Biological and Toxin Weapons Today. Stockholm International Peace Research Institute. Oxford, England: Oxford University Press 13. Douglas, J.D. Livingstone, N.C.1987. America the Vulnerable: The Threat of Chemical and Biological Warfare. Lexington,Mass: Lexington Books. 14. US Department of State. International Terrorism. Washington, DC: DOS; 1989. GIST. 15. Zilinskas, R.A.1990. Terrorism and biological weapons: Inevitable alliance? Perspect Biol Med. 44–72. 16. Bates S.1992. Fairfax man accused of anthrax threat. Washington Post. 17. Kupperman, R.H, Smith, D. M.1991. Coping with biological terrorism. Washington, DC.. 18. US Army Medical Research Institute of Infectious Diseases. Medical Management of Biological Casualties Hand- book . Fort Detrick, Frederick, Md: USAMRIID; August 1993. 19. Wiener, S.L, Barrett, J.1986. Biological warfare defense. In trauma Management for Civilian and Military Physicians. Philadelphia, Pa: WB Saunders.507–528. 20. Caudle L.1994. Major, Medical Corps, US Army. Officer in Charge, Problem Definition and Assessment Team, Operation Vigilant Warrior. Personal communication. 21. Khan A, et al. Public health preparedness for biological terrorism in the USA. Lancet 2000; 356:1179
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You can also send your articles to info@microbiologyworld.com or broneps1@gmail.com Selected ones will be published in our next issue of Jan-Feb 2015. Thanks, Sagar Aryal Editor-In-Chief Microbiology World www.microbiologyworld.com
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