Biomedical subjects

G Pischek

Publications and source records attributed to G Pischek.

12 recordsLinked to original sources

PubMed1982

Pharmacokinetic evaluation of norendimide in rats.

Norendimide, the endo-isomer of the new psychoactive compound noreximide, was studied in rats upon I.V., P.O., and I.P. administration, and the pharmacokinetic parameters were determined from the concentration-time data. The one-compartment model was most appropriate for curve-fitting of all data. The elimination half-life is approximately 11 hours, and hence about 30% longer than that of the parent compound. The volume of distribution is about 85% of the body weight. Upon P.O. and I.P. administration the fraction of drug absorbed is 80% and 94%, respectively. A comparison with the previously reported pharmacokinetic data on noreximide indicates that both compounds, the parent drug and the analog, are completely absorbed and show some first-pass effect.

Administration, Oral↗

PubMed1980

Adenine and hypoxanthine metabolism in phythohemagglutinin-stimulated and unstimulated human lymphocytes.

The uptake and subsequent metabolism of adenine and hypoxanthine in phytohemagglutinin-stimulated and unstimulated peripheral human blood lymphocytes, freshly prepared or cultured, were studied. To investigate the initial step of nucleic acid metabolism the incorporation of 14C-purines into the acid soluble material was examined. No preferential uptake of adenine or hypoxanthine was observed in freshly prepared and cultured lymphocytes during an incubation of 1 h. However, cultured cells utilized approximately 1/3 of the purines compared to freshly drawn cells. Within the cells 2/3 of adenine and 1/2 of hypoxanthine were metabolized to nucleotides (mainly AMP and ADP). Incubation of lymphocytes with PHA for 1 h produced in the freshly prepared cells an increase of adenine- and hypoxanthine-uptake to 191% and 153%, in 48 h stimulated cells to 158% and 132%. There was, however, no change in the relative rates of the metabolic routes though the intracellular concentrations of nucleotides formed increased with adenine as substrate to 152% and with hypoxanthine to 161% during a 1 h stimulation. In contrast no enhanced formation of acid soluble nucleotide formation could be observed with PHA stimulation during 48 h. The increased rates of purine uptake and metabolism apparent 1 h after addition of mitogen may be due to an altered transport mechanism at the beginning of the transformation as an adaptive response to the increased requirements for the synthetic processes soon to follow. Once the lymphocytes are transformed no demand of purines is necessary and the uptake and metabolism is switched off.

Adenine↗

PubMed1979

Purine metabolism in human lymphocytes.

In peripheral human blood lymphocytes the uptake and metabolism of adenine, guanine, and hypoxanthine was investigated. This was achieved by incubation of purified lymphocytes with 14C-purine bases, separation of cells from the incubation medium by a rapid filtration technique, and subsequent separation of the acid soluble material by thin-layer chromatography. No perferential uptake for one of the purine bases was observed. In all cases only traces of 14C-purine bases not added originally and labeled nucleosides could be demonstrated. Approximately 2/3 of adenine and 1/2 of guanine or hypoxanthine were converted to nucleotides. Separation of formed nucleotides showed that adenine and guanine were metabolized mainly to their corresponding nucleotides; hypoxanthine was converted to a considerable amount to adenine nucleotides and only to a small proportion into its own nucleotides. These results demonstrate the predomonance of adenine nucleotide formation in normal human lymphocytes.

Adenine↗

PubMed1979

Pharmacokinetics and metabolism of taglutimide (K-2004) in the rat.

Absorption, blood level course, renal, fecal, and biliary elimination and the metabolisation of 2-(bicyclo[2,2,1]-heptane-2-endo-3-endo-dicarboximido)-glutarimide (taglutimide, K-2004), a new hypnotic-sedative substance, were studied in the rat, and the pharmacokinetic constants were calculated. After oral administration of 10 mg per animal, which corresponds to the 7- to 10-fold human dose, a fast and practically total absorption and a quick and complete excretion was observed. Within 1 h 82% of the dose given were absorbed, and 12 h after the dosing 88% had been excreted again. The elimination was effected nearly exclusively (over 95%) via the urine. Besides 10 defined metabolites only 10% of the drug appeared unchanged.

Animals↗

PubMed1978