Monday, April 29, 2013 C7
HEALTH My sister and I: a story of life and second chances
BRAIN STORMING Scientists are blazing a trail to find a cure for neurological disorders such as Alzheimer’s, writes Sasha Gonzales
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hen US scientists introduced stem cells to the damaged brains of live mice, they were surprised by the results: the treated mice scored significantly better on learning and memory tests than their untreated peers. The study is among a few that offer some hope of methods to heal brain impairment and prevent memory degradation. The mice experiment, conducted at the University of Wisconsin-Madison and published in this month’s issue of Nature Biotechnology, is the first to show that human stem cells can successfully heal “neurological deficits”, according to the lead author, Professor Zhang Su-chun. The researchers from the university’s Stem Cell and Regenerative Medicine Centre damaged a part of the mice brains involved in learning and memory. Then they transplanted lab-cultured human embryonic cells (“mother cells” that have the potential to become any type of cell in the body) in the brain, where the stem cells formed two vital types of brain cells. “These two neuron types are involved in many kinds of human behaviour: emotions, learning, memory, addiction and other psychiatric issues,” says Zhang, a pioneer in this field. Though stem-cell therapy is unlikely to completely repair the brain, it does hold promise for disorders such as Alzheimer’s disease, Down’s syndrome, schizophrenia, epilepsy, depression and addiction. For people who don’t suffer from these conditions, there’s the tantalising chance of retaining sharper memory into old age.
In another study published recently in The Journal of Neuroscience, scientists at the University of Texas Health Science Centre at Houston reversed memory loss in sea snails’ brain cells. This was done by determining when the cells were prime for learning, then retraining the cells through an optimised schedule. “This method may apply to humans if we can identify the same biochemical processes,” says the study’s senior author, John Byrne. “Mathematical models might help design therapies that optimise the combination of training protocols with drug treatments,” he says. The gradual decline of memory is part of the ageing process – it tends to peak in one’s 20s, then levels off, declining steeply in one’s 80s. Some types of memory, however, such as semantic memory (the ability to recall concepts and facts) or procedural memory (how to do tasks), stay constant or may even improve in old age, according to the American Psychological Association. Episodic (which captures the what, where and when of our daily lives) and longer-term memory decline with age.
Take a standard test … to compare your memory against that of healthy people your age JORDAN POPPENK, RESEARCH FELLOW
The ability to process information, learn something new or multitask also typically slows down as we grow older. These memory skills are found in different parts of the brain. The hippocampus is particularly important for remembering events, the basal ganglia for skills and the amygdala for emotional memory. This is why different types of brain injuries can result in different kinds of memory problems, according to Jordan Poppenk, a post-doctoral research fellow at the Princeton Neuroscience Institute. For example, excessive drinking, road accidents and carbon monoxide poisoning can cause trauma to the hippocampus. These lesions to the hippocampus “can result in the loss of ability to remember new things”, says Eric Chen, a clinical professor from the department of psychiatry at Hong Kong University. “Recent memories that have not been wellconsolidated may be lost, too. However, distance memory usually remains intact.” Poppenk says the best way to measure your memory ability is to “take a standard neuropsychological test, which allows you to compare your memory against that of other healthy people your age”. But he says the tests are “blunt instruments” as they measure only one type of memory and the person’s results will be affected by “whether you woke up on the wrong side of the bed, missed your morning coffee, the time of day and many other factors”. People who experience serious memory problems should consult a neurologist. Another question scientists are probing is why some people have better memory than others. It could be for many reasons, Poppenk says, from having a larger posterior hippocampus to simply having more knowledge about the issue or task at hand. life@scmp.com
................................................ Amy Wu life@scmp.com
Memory boosters ............................................. Sasha Gonzales life@scmp.com Omega-3 fatty acids, gingko and vitamin B6 are touted as memory boosters, but a recent study suggests otherwise. Oily, cold-water fish that are rich in omega-3 such as salmon, trout, sardines and tuna are often described as “brain food”. Canadian researchers found that laboratory mice that were fed a diet high in docosahexaenoic acid (DHA), a type of omega-3, had 30 per cent higher levels of DHA in their hippocampus, which helped memory cells better communicate with each other. However, a recent review of published research conducted at St Michael’s Hospital in Toronto has found no evidence to support the claims. There is also no strong evidence for pharmaceutical treatments such as cholinesterase inhibitors, which are used for Alzheimer’s patients, and there is a weak link between physical exercise and better memory, according to the review. The study, published in the Canadian Medical Association Journal, suggests mental exercises – such as computerised memory training programmes or intensive one-on-one cognitive training in memory, reasoning or processing speed – are the best memory boosters. But it seems that views are divided among experts. Hong Kong University Professor Eric Chen says aerobic exercise has been shown to have a direct effect on strengthening the brain’s memory capacity and
facilitating growth in the hippocampus among patients with illnesses such as psychosis. Jordan Poppenk, of Princeton University, believes “brain exercise games” may improve one’s memory within the context of the game, but not memory in general. He suggests using mnemonics, such as the 2,000-year-old Greek memory place method where one imagines certain items housed in a different place, then walks among them and recalls their locations. A study by German scientists published this month in Neuron demonstrates an
A study shows that sleep deprivation can cause memory impairment easy and non-invasive way to enhance memory: playing sounds synchronised with the brain’s slow oscillation rhythm when people are sleeping. This way the study participants were better able to remember word associations they learned the night before. But just getting enough quality sleep could help. A study in The Journal of Neuroscience shows that sleep deprivation can cause memory impairment by increasing adenosine levels – a compound believed to cause memory loss and attention deficit – in the hippocampus.
In my sister’s new book Confessions of a Kidney Transplant Recipient, I am a chapter. Several years ago at Christmas, she gave me the chapter, a rough draft, as a gift. For a gift so personal, I treated it nonchalantly by politely thanking her and placing it to one side. I kept thinking if it were my story, I’m not so sure I’d share it so openly, but that’s my sister. Friends have called my sister, Mary, a little firecracker, as a compliment. She’s outgoing and has a quick wit. She loves to travel and live life to the fullest. For her 30th birthday last August, she wanted to celebrate with a hot-air balloon ride. (I’m not as daring.) She’s not afraid to tell the world her story. She was born with renal failure. She had her first kidney transplant at the age of five and a second when she was 12. Her life and our family’s history for so long revolved around hospitals, doctors and survival. There was a shortage of organs available for donation and a lengthy waiting list for the ones they had. Despite the adversities she’s faced, Mary considers herself lucky. She tackled the book with chutzpah. She blogged a chapter a month, sometimes more. The book, back then just a seed, became a marathon project and as much about her journey as a kidney transplant recipient as it is about hope and inspiration. It is also about public awareness. Here in Hong Kong, the waiting list for organ donations remains lengthy. Case in point: according to the Department of Health as of December 31, the waiting list of 1,808 people for kidneys is the longest among organ/tissue recipients. While the issue remains under the radar, the Hong Kong government has initiatives for public awareness, including the Garden of Life sculpture near the Hong Kong Heritage Discovery Centre of Kowloon Park. Celebrities and public figures, such as Miriam Yeung and Rita Fan, support the cause. The Department of Health’s Centralised Organ Donation Register makes it easy for prospective donors to go online and get an organ donation card. But there is a long way to go. There are also the stories of the donor families. My sister is always thankful to hers. One of her kidneys came from a four-year-old girl who died in an accident. Several years ago, she became an advocate for organ transplants; it was unplanned but came from her passion to help others. She has spent countless hours advocating on Capitol Hill in Washington; she has made speeches to medical professionals; corresponded with politicians; and has become an active board member with organ transplant organisations. For her, it is all about public awareness. But it took me a while to get it. Two summers ago, in a quiet
LAB REPORT
Ask the doctors ................................................ Dr Anthony Siow healthpost@scmp.com Q: Is it possible to have your period and be pregnant? A: Medically speaking, if there is a pregnancy, then a woman should not have a period. However, there is a possibility that bleeding during the very early stages of pregnancy could be mistaken for a period. A small percentage of pregnancies fail, causing a delayed, heavy period. Without a pregnancy test,
............................................... Jeanette Wang jeanette.wang@scmp.com
a woman can assume it is an irregular period. If a faint positive pregnancy test was conducted prior to bleeding, you should seek medical advice. Sometimes, there can also be bleeding in early pregnancy resembling a period. This is termed a threatened miscarriage and you should see a gynaecologist for further evaluation. Dr Anthony Siow is a senior consultant at the Parkway Gynaecology Screening & Treatment Centre in Singapore
Germs winning the war What doesn’t kill you only makes you stronger – that can certainly be said of bacteria. Researchers from the University of Exeter and Kiel University treated E coli with different combinations of antibiotics in laboratory experiments. They found that the bacteria’s rate of evolution of antibiotic resistance speeds up when potent treatments are given. The researchers say too potent a treatment eliminates the non-resistant cells, creating a lack of competition that allows resistant bacteria to multiply quickly. Those cells go on to create copies of resistance genes, which helps them rapidly reduce drug effectiveness. The study was published last week in PLOS Biology. Bad air days prove deadly Long term exposure to air pollution may be linked to heart attacks and strokes by speeding up atherosclerosis, according to a study by US researchers in PLOS Medicine. The research team followed 5,362 people aged between 45 and 84 years old from six US metropolitan areas as part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air). Higher concentrations of fine particulate air pollution (PM2.5) – a problem in Hong Kong – were linked to a faster thickening of the inner two layers of the common carotid artery, an important blood vessel that provides blood to the head, neck, and brain.
Mary Wu (above) after her kidney transplant, and (right) with her sister Amy.
Despite the adversities she’s faced, Mary considers herself lucky moment, my sister asked me if I would sign on as an organ donor. She asked me why I didn’t place the bumper sticker on my car that read: “Don’t take your organs to heaven.” I didn’t have an answer, only that maybe I wasn’t ready. Fast forward to today, and I understand my sister’s passion. One person’s death is another person’s second chance. If not for these donors, my sister may not be here today. Mary has taught me a great deal. Last Christmas, another package arrived from her – three pages of all the people who influenced her, a constellation of close friends and family, the simple things in life she relishes, and things to look forward to including the book. She celebrates life and the anniversaries of both of her transplants. For transplant recipients, life can be an roller coaster. This month my sister will tackle a hip replacement – a side effect of the anti-rejection drugs she takes. We stand anxiously on the sidelines. The one person who sounds somewhat at peace is my sister. The book is complete, and her story is out. I recently asked her if she ever wished she had been born normal. “No, I would never want it otherwise,” she said. “I know what matters and what doesn’t.” She sees the good in life and people, and truly knows what second chances mean. No wonder she doesn’t take a single day for granted. I just purchased copies of my sister’s book. The completion of this marathon project triggers thoughts and ponderings about family, God, life’s mysteries, death and the gift of second chances – a precious lesson that it is better to share than not. The cover stares back at me, and I exhale. I am finally ready to open it. Mary Wu’s book is available at amazon.com. Check out her blog kidneyconfessions.blogspot.com. For more information about organ transplantation in Hong Kong, go to organdonation.gov.hk