In a case–control study of the influence of the use of oral contraceptives on the risk of breast cancer, 4575 women who had received a diagnosis of invasive breast cancer and 4682 controls were interviewed about their use of oral contraceptives. There was no evidence that oral-contraceptive use increased the risk of breast cancer.

The use of low-dose aspirin as prophylaxis against cardiac events or stroke and the presence of Helicobacter pylori infection are both risk factors for upper gastrointestinal tract bleeding from ulcers. In this study, patients taking low-dose aspirin who had both bleeding from ulcers and H. pylori infection had the latter eradicated and were then randomly assigned to receive lansoprazole (62 patients) or placebo (61 patients) and were followed for a median of 12 months while the low-dose aspirin treatment was continued. There was one recurrence of ulcer complications in the lansoprazole group and nine in the placebo group (P=0.008).

In this study of the initial treatment of human immunodeficiency virus (HIV) infection, 653 patients were randomly assigned to treatment with either lopinavir–ritonavir or nelfinavir. All patients also received stavudine and lamivudine. After 48 weeks, there was suppression of HIV RNA to fewer than 50 copies per milliliter in 67 percent of the patients in the lopinavir–ritonavir group, as compared with 52 percent of those in the nelfinavir group (P<0.001).

Cardiac troponin T levels are commonly used to predict risk in patients in whom acute coronary syndromes are suspected. Because cardiac troponin T is cleared by the kidney, it is uncertain whether it still has prognostic value in patients with renal dysfunction. This study indicates that measurement of cardiac troponin T does predict risk in patients with renal impairment and suspected acute coronary syndromes.

The hallmark of membranous glomerulonephritis, a major primary nephropathy, is the presence of immune deposits on the outer aspect of the glomerular basement membrane. The cause of such deposits in humans has eluded detection. The authors of this report studied a neonate whose nephropathy began in utero and who had renal failure and the nephrotic syndrome at birth. Subsequent studies of the infant and his parents documented that alloantibodies had developed in the mother after an earlier miscarriage and that she had a deficiency of neutral endopeptidase. Because she lacked neutral endopeptidase, nephropathy did not develop in the mother, but disease did develop in rabbits that were injected with IgG antibodies from the mother. These antibodies reacted with neutral endopeptidase and were colocalized in subepithelial immune deposits.