Study Suggests that Alzheimer’s Disease Spreads Through the Brain

February 13, 2012 | by

Scientists have long debated whether Alzheimer’s disease starts in separate regions of the brain independently and at different times, or if it begins in one region and then spreads. Data from researchers at Columbia University Medical Center supports the latter model, showing that abnormal tau protein — a key feature observed in the brains of patients with Alzheimer’s disease — propagates along anatomically connected networks, between connected and vulnerable neurons. The study was published earlier this month in the online journal PLoS ONE [1].

Neural network in human brainImage credit: Neurons network in human brain via Shutterstock

The Fat Trap: Why Lost Pounds Return

January 16, 2012 | by

It’s not you. You’re not imagining it. It really, actually, legitimately is harder to keep weight off than it is to lose it in the first place. You really do feel hungrier than you used to, and still the pounds keep creeping back on. This is the conclusion that Dr. Joseph Proietto and his colleagues at the University of Melbourne just published in the New England Journal of Medicine [1].

Lose weightLose weight image via Shutterstock

Inactivity May Encourage the Body to Create New Fat in Fat Cells

January 4, 2012 | by

It’s obvious that obese people more have fat than non-obese people, but it’s not as clear how it happens. Do obese individuals have more adipocytes (fat cells) than lean people, or do they have the same number of adipocytes, just larger ones? It turns out to be both. But the way that comes to pass is just being worked out by scientists. Engineering Professor Dr. Amit Gefen and his colleagues at Tel Aviv University recently demonstrated in a mouse cell line model that preadipocytes (precursors to fat cells) subjected to prolonged periods of “mechanical stretching loads” — the kind of weight we put on our body tissues when we sit or lie down — differentiate significantly faster, and retain significantly larger fat droplets, than those that are not. The research was published in the American Journal of Physiology — Cell Physiology [1].

Lounging couple

Chewing Gum Reduces Risk of Ear Infection in Children

December 21, 2011 | by

Xylitol, or birch sugar, is a sugar naturally found in plums, strawberries, raspberries, and rowan berries. It is often used to sweeten toothpaste and chewing gum since it is as sweet as sucrose but does not cause tooth decay; this is because it cannot be fermented by bacteria that live in our mouths, and instead inhibits their growth. As the key step causing acute ear infections is the colonization of the middle ear by bacteria that move there from the mouth, researchers have hypothesized that xylitol might help prevent acute ear infections as well as tooth decay.

Researchers at the University of Toronto recently performed a meta-analysis of three Finnish studies and found that children who chewed gum — or took other products laden with xylitol, including lozenges or syrup — had about a 25% lower risk of developing an ear infection compared to controls. The study is published in the Cochrane Database of Systematic Reviews [1].

Child ear examination

Lowering Physical Activity Impairs Glycemic Control, Even in Healthy People

December 13, 2011 | by

Low levels of physical activity — like the 5,000 steps per day that Americans typically achieve, which is only about half of the recommended amount — have been implicated in the development of insulin resistance and its progression to full blown type 2 diabetes. However, the studies that suggested this connection were performed under laboratory conditions; they did not use people eating real meals, and they did not assess glycemic variability, so the direct impact of physical activity on glycemic control is not completely clear.

People walking down the street

Elevated postprandial glucose (PPG) often precedes the development of type 2 diabetes, and is a risk factor for adverse cardiovascular events, independently of diabetes status. Thus, Dr. Catherine Mikus and her colleagues at the University of Missouri set out to precisely define the impact of reducing physical activity on PPG and glycemic variability in healthy, active volunteers as they went about their daily lives. The results of their study were recently published in the journal Medicine and Science in Sports and Exercise [1].