To describe the clinical course of severe lupus nephritis and to identify the risk factors for progression to renal failure among patients treated with prednisone and short-term courses of low-dose oral cyclophosphamide.

To identify echocardiographic predictors of arterial thromboembolism in patients with nonrheumatic atrial fibrillation and to determine whether these add to clinical variables for risk stratification.

To compare pyrimethamine plus clindamycin (PC) to pyrimethamine plus sulfadiazine (PS) as a treatment for toxoplasmic encephalitis (TE) in patients with the acquired immunodeficiency syndrome (AIDS).

To identify those patients with nonrheumatic atrial fibrillation who are at high risk and those at low risk for arterial thromboembolism.

To evaluate the safety and immunologic and antiviral effects of combination therapy with zidovudine and dideoxycytidine (ddC) in patients with advanced human immunodeficiency virus type 1 (HIV) infection.

To determine the efficacy of glucose tolerance factor (GTF)-chromium for increasing serum levels of high-density lipoprotein (HDL) cholesterol in patients taking beta-blockers.

To determine the effects of tamoxifen on risk factors for cardiovascular disease in disease-free postmenopausal women.

To compare the efficacy, toxicity, and cost-effectiveness of double beta-lactam therapy with monotherapy.

To determine whether an increase in dietary potassium intake from natural foods reduces the need for antihypertensive medication in patients with essential hypertension.

Seven randomized studies during the past 5 years have evaluated or are evaluating the efficacy of warfarin or aspirin or both in decreasing the risk of embolic events in patients with nonrheumatic atrial fibrillation. By March 1990, two of the studies had been published, both of which showed a statistically significant decrease in embolic events in patients treated with warfarin and a low rate of major bleeding events. The investigators associated with the other ongoing studies were forced to consider how these results should affect the decision to recruit and continue follow-up of patients in their own studies. The Steering Committee of the Canadian Atrial Fibrillation Anticoagulation (CAFA) study thought the newly published results from other studies were valid, clinically important, and generalizable. The committee considered the following options for the CAFA study: continue patient recruitment as planned, provide the data available in CAFA to its External Safety and Efficacy Monitoring Committee for analysis to determine whether the CAFA data already showed a benefit of warfarin, stop patient recruitment but continue to follow patients in the group to which they were assigned, stop the trial immediately and perform a final analysis, and attempt to perform a meta-analysis of all data available from all trials. The Steering Committee of CAFA decided that the evidence of benefit with warfarin, from the two published studies, was sufficiently compelling as to stop recruitment into CAFA without any preliminary examination of the CAFA data.

To determine the median response time to therapy with vancomycin alone or with vancomycin plus rifampin in patients with methicillin-resistant Staphylococcus aureus (MRSA) endocarditis.

To assess the effect of alpha-interferon therapy on hepatitis C viral RNA in serum of patients with chronic hepatitis C.

To compare the survival of patients with medically inoperable or unresectable stage III non-small cell lung cancer treated with thoracic radiotherapy alone or in combination with chemotherapy.

To evaluate foscarnet sodium in treating cytomegalovirus retinitis in patients with AIDS.

To study how changes in gastric acidity induced by omeprazole and pentagastrin affect the absorption of unchanged digoxin and its hydrolytic breakdown products.

To review the incidence of reversible renal insufficiency in patients with hypertensive nephrosclerosis undergoing antihypertensive therapy.

To determine whether relative vitamin D deficiency during the winter months contributes to age-related bone loss and whether rates of change in hard- and soft-tissue mass vary during the year.

To test the hypothesis that a continuous, low-dose infusion of a loop diuretic is more efficacious and better tolerated than conventional intermittent bolus therapy in patients with severe chronic renal insufficiency (CRI).

To evaluate the efficacy and safety of a pH-sensitive, polymer-coated oral preparation of mesalamine in patients with mildly to moderately active ulcerative colitis.

To determine whether antimicrobial therapy for Helicobacter pylori infection accelerates the healing of duodenal ulcers.