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Archive - 2014 - Page

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October 25th

Mosaic Loss of Y-Chromosome Associated with Shorter Life Span, Increased Risk of Cancer

Age-related mosaic loss of the Y chromosome (LOY) from blood cells, a frequent occurrence among elderly men, is associated with elevated risk of various cancers and earlier death, according to research presented on Tuesday, October 21, at the American Society of Human Genetics (ASHG) 2014 Annual Meeting in San Diego. This finding could help explain why men tend to have a shorter life span and higher rates of sex-unspecific cancers than women, who do not have a Y chromosome, said Lars Forsberg, Ph.D., lead author of the study and a geneticist at Uppsala University in Sweden. LOY, which occurs occasionally as a given man’s blood cells replicate – and thus takes place inconsistently throughout the body – was first reported nearly 50 years ago and remains largely unexplained in both its causes and effects. Recent advances in genetic technology have allowed researchers to use a blood test to detect when only a small fraction of a man’s blood cells have undergone LOY. Dr. Forsberg and colleagues studied blood samples from 1,153 elderly men aged 70 to 84 years, who were followed clinically for up to 40 years. They found that men whose samples showed LOY in a significant fraction of their blood cells lived an average of 5.5 years less than men whose blood was not affected by LOY. In addition, having undergone LOY significantly increased the men’s risk of dying from cancer during the course of the study. These associations remained statistically significant when results were adjusted for men’s age and other health conditions. “Many people think the Y chromosome only contains genes involved in sex determination and sperm production,” said Jan Dumanski, M.D., Ph.D., co-author on the study and a professor at Uppsala University.

September 8th

New, Antibody-Based, Non-Steroidal Treatment for Certain Severe Asthmatics

A team of researchers at McMaster University and St. Joseph's Healthcare Hamilton, both in Canada, have successfully evaluated a new, antibody-based drug for certain patients with severe asthma. The drug – named mepolizumab (image)– can replace traditional, steroid-based treatments for a specific subset of patients, resulting in improved outcomes and reduced side effects. The study and manuscript, published online on September 8, 2014 in the New England Journal of Medicine was led in Canada by Dr. Parameswaran Nair, Staff Respirologist, Firestone Institute for Respiratory Health at St. Joseph's Healthcare Hamilton and Professor of Respirology at the Michael G. DeGroote School of Medicine at McMaster University. Dr. Nair and his colleagues recruited the largest number of participants for this global study. "This new drug is the only therapy that has been proven to be effective in well-established clinical trials to help reduce doses of steroid-based treatments such as prednisone for those with severe asthma," said Dr. Nair, adding that the paper reconfirms the team's observation published in the New England Journal of Medicine in 2009. Patients with severe asthma often require high doses of steroid-based treatments that can significantly impair their quality of life. These high doses can cause debilitating side effects including mood swings, diabetes, bone loss, skin bruising, cataracts, and hypertension. Previous research at the Hamilton institutions has identified specific types of patient with severe asthma who have an overabundance of a particular type of white blood cell (eosinophils) present in their sputum. These patients often suffer from the most severe asthma symptoms and can only be treated through steroid-based medications such as prednisone.

August 29th

Good to Bad and Bad to Good--“Tour de Force” by Nobel Prize Winner and MIT Team Reverses Emotional Associations of Memories--Possible Applications in Mental Illness

Most memories have some kind of emotion associated with them: recalling the week you just spent at the beach probably makes you feel happy, while reflecting on being bullied provokes more negative feelings. A new study by MIT neuroscientists reveals the brain circuit that controls how memories become linked with positive or negative emotions. Furthermore, the researchers found that they could reverse the emotional association of specific memories by manipulating brain cells with optogenetics — a technique that uses light to control neuron activity. The findings, described online on August 27, 2014 in Nature, demonstrated that a neuronal circuit connecting the hippocampus and the amygdala plays a critical role in associating emotion with memory. This circuit could offer a target for new drugs to help treat conditions such as post-traumatic stress disorder, the researchers say. “In the future, one may be able to develop methods that help people to remember positive memories more strongly than negative ones,” says Dr. Susumu Tonegawa (image), the Picower Professor of Biology and Neuroscience, director of the RIKEN-MIT Center for Neural Circuit Genetics at MIT’s Picower Institute for Learning and Memory, and senior author of the paper. Dr. Tonegawa won the Nobel Prize for Physiology or Medicine in 1987 for his discovery of the genetic mechanism that produces antibody diversity. The paper’s lead authors are Dr. Roger Redondo, a Howard Hughes Medical Institute postdoc at MIT, and Joshua Kim, a graduate student in MIT’s Department of Biology. Memories are made of many elements, which are stored in different parts of the brain.

Engineered Molecule May Protect Brain from Detrimental Effects Linked to Diabetes

Researchers at the Hebrew University of Jerusalem have created a molecule that could potentially lower diabetic patients' higher risk of developing dementia or Alzheimer's disease. Recent studies indicate that high levels of sugar in the blood in diabetics and non-diabetics are a risk factor for the development of dementia, impaired cognition, and a decline of brain function. Diabetics have also been found to have twice the risk of developing Alzheimer's disease compared to non-diabetics. Now, researchers from the Hebrew University of Jerusalem have found a potential neuro-inflammatory pathway that could be responsible for the increases of diabetics' risk of Alzheimer's and dementia. They also reveal a potential treatment to reverse this process. The research group led by Professor Daphne Atlas, of the Department of Biological Chemistry in the Alexander Silberman Institute of Life Sciences at the Hebrew University, experimented with diabetic rats to examine the mechanism of action that may be responsible for changes in the brain due to high sugar levels. The researchers found that diabetic rats displayed high activity of enzymes called MAPK kinases, which are involved in facilitating cellular responses to a variety of stimuli, leading to inflammatory activity in brain cells and the early death of cells. The study shows that the diabetic rats given a daily injection of the sugar-lowering drug rosiglitazone for a month enjoyed a significant decrease in MAPK enzyme activity accompanied by a decrease in the inflammatory processes in the brain. According to the authors, this finding represents the first unequivocal evidence of a functional link between high blood sugar and the activation of this specific inflammatory pathway in the brain.