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Biomedical subjects

K R Sommer

Publications and source records attributed to K R Sommer.

6 recordsLinked to original sources
PubMed1975

The use of gas chromatographic-mass spectrometric-computer systems in pharmacokinetic studies.

Pharmacokinetic studies involving plasma, urine, breast milk, saliva and liver homogenates have been carried out by selective ion detection with a gas chromatographic-mass spectrometric-computer system operated in the chemical ionization mode. Stable isotope labeled drugs were used as internal standards for quantification. The half-lives, the concentration at zero time, the slope (regression coefficient), the maximum velocity of the reaction and the apparent Michaelis constant of the reaction were determined by regression analysis, and also by graphic means.

Chromatography, Gas↗
PubMed1975

Identification and quantification of drugs in human amniotic fluid.

Since drugs administered to gravid females are rapidly transferred to the fetus, transplacentally acquired drugs and drug metabolities should be excreted by the fetus into amniotic fluid. Analyses have been carried out on amniotic fluid obtained at the time of delivery using a gas chromatograph-mass spectrometer-computer system. The drugs that have been identified are caffeine, secobarbital and phenobarbital. Theobromine (3,7-dimethylxanthine) and smaller amounts of 1,7- and 1,3-dimethylxanthine, three metabolites of caffeine, were also found in amniotic fluid, but metabolites of secobarbital and phenobarbital were not detected. It is known that human fetal tissues have active enzyme systems for metabolizing drugs, but these results suggest that this may be a selective rather than general occurence.

Amniotic Fluid↗
PubMed1972

A modified procedure for fractionating histones.

A method is described, which is capable of fractionating histones obtained from any animal source into five major groups. Although the method is based on procedures initially developed by E. W. Johns (1964), involving differential solubility in solutions of acids and of ethanol, it gives a cleaner separation and possesses the considerable advantage that the starting material is whole histone rather than a nucleoprotein preparation.

Animals↗