Thursday, March 26, 2009

Supersize that Fire Department...

It seems no group is immune to the ever increasing prevalence of overweight and obesity in our U.S. population. Reuters Health is reporting on a recent study published in the journal Obesity, suggesting that new fire and emergency recruits are overweight and unhealthy. The study was limited to a cohort of recruits in Massachusetts but could this be representative of National or Regional trends? Analysis of Body Mass Index or BMI (reflecting height to weight ratio) showed that almost 80% of the recruits were overweight and over 30% were obese in this young (average age of 26.3 years) recruit population of future emergency workers. However, in some cases BMI does not necessarily reflect that a person's body weight is unhealthy or obesity. For example if a study was analyzing BMI of high school or college football players with unusually large amounts of muscle mass. In such as scenario, BMI does not reflect health and weight very accurately. However, this study suggested that the BMI elevations did not necessarily reflect increased skeletal muscle mass in these recruits. In fact, the study appears to have observed higher blood pressures, worsened metabolic profiles, and lower exercise tolerance in those recruits with higher BMI. The authors state the following:
"Excess weight is highly prevalent and associated with elevated cardiovascular risk among (these) future emergency responders. These findings in a population expected to perform demanding duties supporting public safety merit prompt public health intervention."

"Emergency responders should be fit to safely perform strenuous duties. In particular, young recruits are expected to be at or near peak career fitness."
The statements may seem pretty harsh but truthful since we can all imagine that the strenuous nature of emergency work requires that rescuers have excellent cardiovascular fitness and muscular strength. Otherwise who is going to race up those 12 flights of stairs and then carry you out of that burning building?! Check out the Reuters Health article (link) or better yet check out the abstract of the actual research study published in the journal Obesity (link).

~~ BIO26 ~~

Monday, March 16, 2009

Fighting peanut allergy with peanuts?

The New York Times published an interesting article about efforts to treat children suffering from food allergies. Check out the full article here (link). The article discusses recent work by scientists that appears to be successful in treating kids with potentially life threatening allergy to peanuts. The work of Researchers, including Dr. Wesely Burks of Duke University, showed that some patients could be treated by exposing them to very, very small amounts of peanuts. The amount of peanuts was progressively increased overtime until the kids could eat several peanuts without an allergic reaction. The tests were performed under careful medical supervision and the article warns that parents or allergy sufferers should not try this experimental approach themselves. But this research could lead to an eventual treatment that could allow kids with food allergies to eat these foods or at least live without fear of trace amounts of allergens in their food.

"The new treatment uses doses of peanuts that start as small as one-thousandth of a peanut and eventually increase to about 15 peanuts a day. In a pilot study at Duke University and Arkansas Children’s Hospital in Little Rock, 33 children with documented peanut allergy have received the daily therapy, which is given as a powder sprinkled on food. Most of the children are tolerating the therapy without developing allergic reactions, and five stopped the treatment after two and a half years because they could now tolerate peanuts in their regular diet. But four children dropped out because they could not tolerate the treatment."

~~ BIO26 ~~

Friday, March 13, 2009

Protecting women from HIV...

One of your classmates brought this to my attention (thanks Kristin)... pretty interesting stuff. Recent research has been investigating creams and gels that can potentially reduce HIV transmission to women. As we discussed in class, HIV tends to infect immune cells such as macrophages (dendritic cells too?) and Helper T cells (CD4+ lymphocytes). The transmission often takes place in the vaginal mucosa and epithelium. Gels or creams containing chemicals that destroy the virus (microbicides) or prevent the viral infection of the immune cells would reduce transmission, and hopefully decrease or prevent the spread of HIV.

A recent study published in the journal Nature showed reduced virus transmission in a primate model of HIV using the chemical glycerol monolaurate (an ingredient reportedly used in ice cream, cosmetics and found in breast milk). Researchers tested glycerol monolaurate, spiked into K-Y jelly, in their study using macaque monkeys. They put the gel into the vagina of the monkeys and then applied SIV, a monkey version of HIV. Monkeys treated with the chemical appeared to be protected from vaginal HIV exposure while untreated monekys became infected with HIV. Here is a link to a Reuters article reporting the research (link) and here is a link to the PubMed citation for the actual study (link).

Another interesting fact discussed in the article is related to initial HIV infection and transmission. It is reported that HIV infects or activates resident immune cells in the vaginal mucosa like macrophages and dendritic cells. These cells induce inflammation (via cytokines) and most importantly they cause the recruitment of helper T cells (CD4+) to the site of viral infection, in this case the vagina. It seems that this initial recruiting of CD4+ cells to the local site of infection is an important step the systemic spread of HIV which further infects CD4+ lymphocytes throughout the body.

Interestingly, I recall a study not too long ago investigating a microbicide cream used in the vagina that was designed to reduce or prevent HIV transmission. The study was halted because the researchers found the gel actually increased HIV infection... apparently the gel caused inflammation and irritation of the vagina which would then increase the risk of HIV infection in the female. Obviously these strategies have some potential but research and product development have a long way to go.

~~ BIO26 ~~

Sunday, March 8, 2009

Mrs. Doubtfire needs heart surgery...

You may have heard the news that comedian and actor Robin Williams needs to have heart surgery. He reportedly will have aortic valve replacement to fix his left semilunar valve, known more commonly as the aortic valve or aortic semilunar valve. Valve replacement is commonly performed to fix aortic stenosis when the valve opening becomes narrowed. Stenosis of the aortic valve limits the pumping action of the left ventricle and can lead to low exercise tolerance and also left ventricular enlargement. Another less common issue is aortic valve insufficiency when the valve is leaky. This can lead to backflow or regurgitation of blood into the ventricle from the aorta. Options to fix the aortic valve include repair of the valve leaflets or total replacement using an artificial valve (mechanical) or bioprosthetic valve (biological) derived from cadaver, porcine (pig) or bovine (cow) tissues. You can read more about aortic valve replacement at WebMD (link) and watch a webcast of a minimally invasive aortic valve replacement at OR-live (link).

~~ BIO26 ~~