Marijuana use may increase the risk of ectopic (tubal) pregnancies, researchers at Vanderbilt University Medical Center reported this week. The researchers studied CB1, a ”cannabinoid” receptor that binds the main active chemical for marijuana, delta-9-tetrahydrocannabinol (THC). In pregnant mice that lacked the gene for the receptor, or in which the receptor was blocked, the embryo failed to go through the oviduct — the tube leading from the ovaries to the uterus. The same thing happened in normal mice when the receptor was over-stimulated.

Although black men in the United States are more likely than white men to be diagnosed with advanced prostate cancer and have a two-fold greater risk of dying from it, they are significantly less likely to be screened for prostate cancer, according to a Dana-Farber Cancer Institute and Brigham and Women’s Hospital study. In a study involving more than 67,000 men age 65 years and older, the researchers found that blacks were 35 percent less likely than whites to undergo prostate-specific antigen (PSA) testing.

Adding folic acid to food can dramatically reduce the incidence of spina bifida and other birth defects. A new study shows that the proportion of babies born with neural tube defects in the province of Newfoundland and Labrador dropped by 78% after the Canadian Government directed that folic acid must be added to flour, cornmeal and pasta. The study supports the continuation of this food fortification strategy.

For the second time in two years, scientists at the Stanford University School of Medicine have discovered a new type of regulatory T cell that reduces asthma and airway inflammation in mice, bolstering the theory that a deficiency of such cells is a prime cause of the breathing disorder as well as allergies. The team’s research not only provides a detailed profile of these newfound cells but also sheds light on how such cells are related to other T cells and suggests that there exists a spectrum of regulatory T cells, known as Tregs, to be identified and studied.

A study of mainly unwed, U.S. urban parents finds that fathers of infants in poor health are less likely to be living with the child’s mother following the child’s first birthday than fathers of healthy children. The study, published in the latest issue of the journal Demography, also finds that having an infant in poor health decreases the chances a couple who had been living together (either married or cohabiting) at the time of the child’s birth still would be living together 12 to 18 months later. ”Within a very short period, having a child in poor health increased the likelihood the parents became less involved.”