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Biomedical subjects

M G Horning

Publications and source records attributed to M G Horning.

At least 37 records · Page 2Linked 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

An investigation of recurrent pine oil poisoning in an infant by the use of gas chromatographic-mass spectrometric methods.

An 18-month-old infant required six hospital admissions in a period of six months for episodes consisting of coughing, respiratory depression, hematemesis, coma, dehydration, and lesions about the mouth. A negative history of ingestion of toxins was repeatedly obtained from the family and two home inspection by the local Health Department failed to identify potential toxins. Metabolic work-up was entirely negative. Utilizing methods of GC-MS, metabolites of a-terpineol were isolated from infant urine on two admissions to the hospital. These metabolites were confirmed by mass spectrometry to be the same metabolites excreted by Sprague-Dawley rats injected with a-terpineol or pine oil. The child had no additional episodes after physical separation from the home environment.

Animals↗
PubMed1975

Clinical applications of gas chromatograph/mass spectrometer/computer systems.

Gas chromatograph/mass spectrometer/computer systems can be used to quantify a wide variety of compounds of clinical interest. A quadrupole instrument operated in the chemical ionization (Cl) mode was used in these studies. Because of the sensitivity and specificity of selective ion detection, it is possible to make measurements routinely in the nanogram to picogram range, with 0.1-1.0 ml samples of plasma and 1-5 ml samples or urine. Internal standards, preferably stable-isotope-labeled compounds, were added to the biological samples before isolation was begun. We describe clinical applications of these procedures to problems in toxicology, pharmacokinetics, and perinatal pharmacology.

Autoanalysis↗
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↗