Stress echocardiography in women.

The diagnosis of coronary heart disease in women has been thought to be more difficult than in men, owing to the overall lower prevalence and severity of disease in women, as well as more subtle clinical presentations. Exercise electrocardiography is associated with a high rate of false-positive results. In contrast, exercise and pharmacologic stress echocardiography have been shown to have high sensitivity, specificity, and prognostic value in women, comparable to that obtained in a male population. Although exercise thallium provides high f disease accuracy, due to its cost, availability, and radiation exposure, it may not be the ideal initial test in women. Thus, compared with other modalities, the advantages of stress echocardiography include its lower cost, availability, and high diagnostic accuracy. In the evaluation of women with chest pain, the initial step should involve clinical stratification into low, moderate, or high-probability groups based on symptoms, age, and cardiovascular risk factors. In women with atypical chest pain and a low probability of coronary heart disease, further testing should be avoided because any positive result is likely to be falsely positive. In those women with a moderate likelihood of disease, the most efficient and cost-effective strategy includes stress echocardiography as the initial test. This approach avoids the high rate of false-positive results with subsequent unnecessary angiography generated by exercise electrocardiography, as well as minimalizing false-negative results, which would lead to delays and potential increase in morbidity and mortality from untreated coronary heart disease. The optimal strategy for women at high clinical risk may be either exercise echocardiography or cardiac catheterization as the initial test. Although the diagnosis of CAD in women is different than in men, it is not necessarily more difficult. Astute clinical evaluation, in conjunction with judicious use of diagnostic testing, yields excellent results.

The interaction of CD4 with HIV-1 gp120.

CD4 is an integral cell surface glycoprotein that is able to enhance T cell specific antigen responses when it interacts with its physiological ligand, class II major histocompatibility (MHC) molecules. In addition, CD4 is a specific cell-surface receptor for the human immunodeficiency virus-1 (HIV-1). Infection by HIV-1 is initiated by the binding of the envelope glycoprotein, gp120, to the first domain of CD4. The binding of CD4 to class II MHC is inhibited by gp120, one possible mechanism for immunosuppression in AIDS patients. In addition, the CD4/gp120 interaction may directly inhibit T cell function. Recently we have synthesized small molecules (CPFs) that specifically inhibit this interaction. CPFs bind to gp120 and prevent the binding of gp120 to CD4, and also inhibit the infectivity of HIV-1.