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Biomedical subjects

F P Siegel

Publications and source records attributed to F P Siegel.

12 recordsLinked to original sources
PubMed1992

Comparison of the pharmacokinetics and electrocardiographic effects of sublingual and intravenous verapamil.

Using a dog model, a sublingual form of the free base of verapamil (SLV) was developed with the intent of avoiding stereoselective first-pass metabolism and the necessity of intravenous administration. Intravenous verapamil (IVV) 5 mg and SLV 40 mg or 60 mg were sequentially administered to seven healthy human volunteers. Electrocardiograms and serum concentrations were obtained before and periodically from 5 to 480 minutes after each dose. The time to peak serum concentration (mean +/- SD) was 77.6 +/- 38.1 minutes after SLV. Bioavailability of SLV was 58.2 +/- 36.9% compared to IVV. Verapamil half-lives after IVV and SLV were 2.83 +/- 0.93 and 2.28 +/- 0.45 hours (NS), respectively. In one subject, the time to peak effect was delayed and overall change in PR interval was minimum. In the remaining six subjects, the maximum percentage increases in PR interval after IVV and SLV were 20.6 +/- 6.4% and 14.8 +/- 5.5% (p less than 0.05), respectively. Times to peak increase in PR interval were 28.3 +/- 15.7 and 57.0 +/- 17.5 minutes after IVV and SLV (p less than 0.05), respectively. Analysis of plots of percentage change in PR interval versus serum concentration revealed a shift to the right and therefore, lesser effect of SLV than of IVV in six subjects. All seven subjects complained of oral numbness and bitter taste. In conclusion, SLV is inferior to IVV in terms of rate and extent of absorption and pharmacologic effect in delaying atrioventricular nodal conduction. Probably SLV has little clinical utility because of its slow onset and poor tolerance.

Administration, Oral↗
PubMed1978

Hv(1), a variable-region genetic marker of human immunoglobulin heavy chains.

A new antigenic determinant was discovered with a hemagglutination-inhibition assay system. Designated Hv(1), it is located in the variable region of human immunoglobulin heavy chains of the G, M, and A classes. Pedigree and population analyses suggest that it has an autosomal dominant mode of inheritance. This represents the first description of an allotypic determinant in the variable region of human immunoglobulins.

Binding Sites, Antibody↗
PubMedDate not supplied

Red cell exchange: treatment of babesiosis in a splenectomized patient.

A splenectomized woman with a history of hepatic disorders was diagnosed as having babesiosis. The patient was unsuccessfully treated with chloroquine and with pentamidine isothionate. A parasitemia of 15 per cent was reduced permanently to less than 1 per cent after a red blood cell exchange, but a low grade parasitemia still existed 10 months after onset. On two separate occasions, the patient was found to have selective IgA deficiency, a reduction of T lymphocytes, and a reduction in function of both T and B lymphocytes. This case represents the highest and the longest duration of parasitemia ever recorded. It reports the first use of pentamidine and red blood cell exchange transfusion in human babesiosis, one of the earliest diagnosed cases of babesiosis, and the most severe clinical case to survive.

Adult↗