Bisher AKIL, MD

Archive for April 1st, 2009|Daily archive page

Enhance the Immune Response to HIV

In Immune System on April 1, 2009 at 12:53 am

When a viral infection cannot be eradicated and becomes chronic, the immune system gets exhausted. Human studies have shown that lymphocytes that are exhausted by chronic HIV infection display greater numbers of a receptor called programmed death 1 (PD-1). In an in vitro study, researchers found that an antibody that blocked the ability of PD-1 to activate its suicidal signals allowed lymphocytes to fight HIV more effectively (JW Gen Med Oct 10 2006).
Nine monkeys were treated with partially humanized PD-1 antibodies at 10 weeks or at 90 weeks after they were infected with simian immunodeficiency virus (SIV; a cousin of HIV). Five SIV-infected control monkeys were treated with an antibody against another receptor. The active treatment greatly increased the numbers and the function of both virus-specific CD8+ T cells and memory B cells. Treatment also greatly reduced viral load and led to a remarkable difference in mortality: 150 days after treatment, no treated monkeys, but four controls (80%), had died. Safety studies revealed no abnormalities in liver, kidney, or marrow in treated animals.

Aspirin and Heart Disease

In Heart on April 1, 2009 at 12:38 am

The U.S. Preventive Services Task Force now recommends that aspirin be used in men to prevent MIs (Myocardial Infarction) — and in women to prevent ischemic strokes — when these benefits outweigh the risks for gastrointestinal bleeding.

The task force considers older age and male sex as the major risk factors for gastrointestinal bleeding, followed by upper GI pain, ulcers, and NSAID use.

The recommendations, published in Annals of Internal Medicine, update the USPSTF’s previous statement, released in 2002. The current statement factors in evidence from the Women’s Health Study that “aspirin may have differential benefits and harms in men and women.” The task force also concludes that evidence is “insufficient” to weigh the benefits and harms of aspirin prophylaxis among people over age 79 — and that use among men under 45 or women under 55 should not be encouraged. An editorialist writes: “Aspirin continues to be underused, and the routine incorporation of the USPSTF’s recommendations … [will] prevent many thousands of cardiovascular events every year.”
Here is a summary of the recommendations to physicians:
1. Encourage men age 45 to 79 years to use aspirin when the potential benefit of a reduction in myocardial infarctions (heart attack) outweighs the potential harm of an increase in gastrointestinal hemorrhage. (A recommendation)
2. Encourage women age 55 to 79 years to use aspirin when the potential benefit of a reduction in ischemic strokes outweighs the potential harm of an increase in gastrointestinal hemorrhage. (A recommendation)
3. Evidence is insufficient to assess the balance of benefits and harms of aspirin for cardiovascular disease prevention in men and women 80 years or older. (I statement)
4. Do not encourage aspirin use for cardiovascular disease prevention in women younger than 55 years and in men younger than 45 years. (D recommendation).

HIV Related High Lipids is Difficult to Treat

In Heart on April 1, 2009 at 12:30 am

Dyslipidemia (abnormal lipids in blood) is common in HIV-infected patients, but treatment outcomes are often unsatisfactory. In this study from Kaiser Permanente in California, investigators compared responses to lipid-lowering therapy between 829 HIV-infected patients and 6941 uninfected controls, all with laboratory evidence of dyslipidemia. The HIV-infected patients had significantly smaller LDL (low density lipoprotein) declines in response to statin therapy than their HIV-negative counterparts (reduction, 25.6% vs. 28.3%); within the HIV population, pravastatin (Pravachol®) was less effective than other agents (simvastatin – Zocor®, lovastatin – Mevacor®, or atorvastatin- Lipitor®). Response to fibrate therapy (gemfibrozil – Lopid®) was also worse among HIV-infected patients, particularly those receiving PIs. Three cases of rhabdomyolysis occurred in the HIV-infected group versus one in the control group; laboratory abnormalities occurred in fewer than 5% of those with HIV infection.

Too Much Red & Processed Meats Can Kill You

In General Health on April 1, 2009 at 12:12 am

High intake of red and processed meats is associated with increased risk for death in older adults, while white meat may have a protective effect, reports Archives of Internal Medicine.
More than a half million adults aged 50 to 71 completed food-frequency questionnaires and then were followed for 10 years; during that time, some 48,000 men and 23,000 women died.
After adjustment for confounders including BMI and smoking status, men and women in the highest quintile of red meat intake had significantly increased risks for overall mortality, cancer-related deaths, and cardiovascular-disease–related deaths, relative to those in the lowest quintile. High intake of processed meat was also associated with increased mortality risks.
Conversely, consumption of white meat (poultry and fish) was associated with significantly decreased risks for total and cancer-related mortality.
Comments: Although the results are intuitively not surprising, this study gives evidence to what we know. One possible explanation for increased cardiovascular disease is elevated blood pressure has been shown to be positively associated with higher intakes of red and processed meat, even though the mechanism is unclear, except that possibly meat may substitute for other beneficial foods such as grains, fruits, or vegetables.BA