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Biomedical subjects

G Schwemer

Publications and source records attributed to G Schwemer.

3 recordsLinked to original sources

General linear models for multicenter clinical trials.

The use of generalized linear models (GLM) in the analysis of multicenter clinical trials is commonplace. Currently, diverse opinion exists as to the proper modeling approach in this setting. This paper provides a description of the technical backdrop underlying the model selection and discusses the pros and cons of the usual parameter estimators. Arguments are given favoring a model incorporating a term for interaction effect while attenuating the effects of small centers.

Clinical Trials as Topic↗

Short- and long-term treatment of stable effort angina with nicardipine, a new calcium channel blocker: a double-blind, placebo-controlled, randomised, repeated cross-over study.

This study evaluated 1 year the efficacy of therapy with nicardipine in patients with chronic stable angina pectoris. Twenty-five male patients were entered. After a placebo run-in phase, the patients received nicardipine 30 mg, nicardipine 40 mg, and placebo, three times daily given in random, double-blind manner for 8 weeks. A double-blind, cross-over study comparing nicardipine with placebo was then undertaken. After 5 months of open treatment with nicardipine 90 or 120 mg day-1, patients received either placebo or nicardipine for 3 weeks, each followed by the alternative treatment for an additional 3 weeks and further open-label treatment with nicardipine for another 3-5 months. There were no significant changes in the PR, QRS or QT intervals, or in the QRS pattern during the short-term and long-term studies. There were no significant differences in mean heart rate after nicardipine compared with baseline. During treatment with nicardipine 120 mg day-1, patients reported significantly fewer anginal attacks compared with placebo, and nitroglycerin consumption also decreased. Nicardipine increased treadmill time, time to onset of angina, and time to one mm ST segment depression. These effects were maintained after 6 months of continued nicardipine therapy. Adverse effects were minor and well tolerated and included headache, dizziness, gastrointestinal upset, flushing paraesthesia and pedal oedema. Abrupt withdrawal of nicardipine at the end of the study resulted in a rapid return of the original symptoms but without further deterioration from the baseline measurements. Nicardipine was effective in the treatment of stable effort angina pectoris; this benefit was maintained for the entire year of treatment.

Adult↗

8402 human cell culture--a model for evaluating bilirubin-albumin interactions with drug.

The effect of therapeutic concentration of sulfisuxazole (sulfa) on the bilirubin uptake and viability of 8402 cells in culture was studied. The total bilirubin was kept constant at 24 microM and albumin was added to obtain bilirubin-albumin molar ratio (BAMR) ranging from 0.5 to 2. The effect of sulfa on unbound bilirubin (UB) was measured by the peroxidase assay. Sulfa increased UB at all BAMR's more so at 1.5 and 2.0 (P less than 0.05). Significant increase in bilirubin uptake/cell with a corresponding decrease in cell viability was noted with sulfa at BAMR's greater than 1 (P less than 0.05). The LD50 of these cells was 73-86 nM of UB. A plot of cell viability versus UB for the combined control and sulfa data (r2 = 0.94) confirms that the decrease in cell viability with increasing BAMR is explained by the corresponding rise in UB. Therefore, increase in UB by sulfa leads to toxicity of 8402 cells. Thus, we speculate that they may be used to study the mechanism of bilirubin neurotoxicity induced by similar drugs.

Albumins↗