"A" Weapon in Superbug's Arsenal Revealed
Alice Prince, M.D., professor of pediatrics, and her colleagues have now found that Protein A, a common component of the outside walls of infectious staphylococci, are chiefly responsible for the bug's deadly effects in the lung and possibly other sites of infection. Their study, published in the August issue of Nature Medicine, also shows that bacteria that lack Protein A do not mobilize the leukocyte response and do not cause death in mice, suggesting a potential new approach to treating patients.
The researchers found that Protein A attracts large numbers of leukocytes into the lung by mimicking the immune system's chief instigator of inflammation, TNFalpha. As a TNFalpha-look-alike, Protein A binds to the TNFalpha receptor in the lung and kicks off a cascade of events that culminates in leukocyte infiltration.
The destructiveness of Protein A was clearly illustrated in experiments where mice were inoculated with either wild type staph or staph deficient in Protein A. One-quarter of the mice infected with wild type staph died, while the protein A-deficient strain killed none.
The study's lead author, Marisa Gomez, Ph.D., post-doctoral research fellow, also showed that drugs that target the TNF alpha pathway may be useful in treating staph-induced pneumonia. Soluble forms of the receptor, called TNFalpha receptor antagonists, bind Protein A and prevent it from activating the real TNFalpha receptor. In mice, Dr. Gomez showed that blocking the TNF alpha receptor protected the mice from adverse effects of the bacteria. As similar drugs are already FDA approved, targeting the TNF alpha pathway may provide a novel mechanism to prevent or even treat S. aureus pneumonia.
Little Ovarian Cancer Risk Found with Fertility Drugs
Researchers at Columbia, the National Cancer Institute, and three other institutions have found little correlation between the development of ovarian cancer and the use of ovulation-stimulating drugs. The research was published in the June issue of Obstetrics and Gynecology.
The investigators, including Carolyn Westhoff, M.D., professor of obstetrics and gynecology, epidemiology, and population and family health at CUMC, collected data from more than 12,000 patients evaluated for infertility between 1965 and 1988. As expected, the infertile women experienced more ovarian cancer than the general population.
The investigators, however, found no additional risk of ovarian cancer among the women who used the drug clomiphene or gonadotropins to stimulate egg production, compared with patients in the study who did not receive these drugs. The researchers caution, however, that clomiphene users in the study who never conceived had a slightly higher risk of developing ovarian cancer and suggest that continued monitoring of the long-term risks and effects associated with these fertility drugs is still needed.
"Start Right" Improves Harlem's Immunization Rates
A new Mailman School of Public Health study has found that immunization rates within the African-American community in Harlem have surpassed the national average for all African-American children and equaled the national average for all children. The results are attributed to a highly successful community-based immunization program known as Start Right, which was launched in 2002 in Harlem and Washington Heights/Inwood.
The Start Right Coalition grew out of the Northern Manhattan Community Voices Collaborative now part of the Center for Community Health Partnerships as a response to the community's desire to take action against their lagging child immunization rates. While the coalition has its base in the Heilbrunn Department of Population and Family Health, it was conceived, planned, and implemented through a coalition of 23 member groups whose cornerstone is integration of immunization promotion activities into the ongoing social service programs within its network of community social service organizations.
According to the study, 2,433 children under the age of five were enrolled in the Start Right program in 2003, a fourth of those eligible in the community and substantially larger than the number enrolled in 2002.
Sally Findley, Ph.D., clinical professor of population and family health (in pediatrics) at Mailman and director of the Northern Manhattan Start Right Coalition, says: "We are excited that our coalition is truly making a difference, narrowing the gap in immunization coverage between our community and the rest of the nation. We started the program with immunization rates 13 percent below the national average, and now the children in our program have immunization rates at or above the national average."