Biomedical subjects
Publications and source records attributed to T A Rejent.
An aspirin overdose by an eight-month primigravida proved to be the mechanism of death for the fetus. Clinical progress of the mother and postmortem concentrations of salicylate in the fetus are listed exhibiting the fetal survival time of about 18 to 20 h post ingestion by the mother.
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Gas chromatographic methodology for the determination of d-propoxyphene in blood and liver samples is given. The method results in a clean extract and sharp response peaks. Quantitation is based on peak height ratios of propoxyphene and pyrroliphene. Post-mortem levels in blood range from 0.1-0.7 mg/dl; in liver from 1.1-18.9 mg/100 gm. The highest blood level has the lowest blood-liver ratio, the rest being widely variable. The incidence of propoxyphene in accidental and suicidal deaths appears to be increasing steadily.
We assessed optimal conditions for assay of porphobillinogen synthase (EC 4.2.1.24) activity in human blood containing abnormally high concentrations of lead. Zn2+and -SH, both required for complete activation of the enzyme, had additive effects. Using a modified method based on these studies, we found blood lead concentration to be strictly proportional to ln(activated/nonactivated) enzyme activity. One brand of commercially available "lead-free" tubes contained a substance that interfered with this relationship. In vitro studies, with the modified assay, showed ALAD to be activated by low concentrations but inactivated by high concentrations of Hg2+, Cd2+, and ethylenediaminetetraacetate. We fouund no genetically influenced differences among unexposed individuals when in(activated/nonactivated) enzyme activities were compared. The technique is suitable for use in screening for lead poisoning in humans.
We studied 2500 patients suspected to be drug-overdose victims. Blood samples were quantitatively screened for the most commonly abused drugs, including diazepam. Of these, 61% had positive findings, including diazepam in about one of every four. A new rapid, simple, and quantitative gas-chromatographic method for simultaneous analysis of diazepam and sedatives (in two instruments) is described. A single extraction at low pH is used, preserving the balance of the sample to be used for confirming methods via ultraviolet spectrophotometry and thin-layer chromatography. Prevalance of other positive findings is also listed, and findings for diazepam are categorized by age.
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Thin-layer chromatography (TLC) and enzyme immunoassay (EMIT) were coordinated to produce unequivocal identification of certain substances. Samples were extracted and subjected to TLC. After development, "positive" spots were scraped from the plate, buffered, centrifuged, and subjected to EMIT. Interferences were not encountered.
The purpose of this study was to compare the qualitative results obtained by the EMIT Cannabinoid Assay with RIA and two different GC/MS techniques in the analysis of urine specimens for evidence of marijuana use. Reliability of the enzyme immunoassay was assessed from studies on accuracy, precision, and recovery. Precision studies with calibration standards and controls yielded coefficient of variation (C.V.) of 1.0 to 2.8% for assay response rates and approximately 30% in terms of concentration units, illustrating the semi-quantitative nature of the assay. A preliminary recovery study verified that the assay could discriminate effectively between urines apparently devoid of cannabinoids and those spiked at the detection limit, 50 ng/mL. MOst samples determined as positive by the enzyme immunoassay yielded the same qualitative results when analyzed by RIA or GC/MS, as well as by EMIT in an independent facility. The confirmatory studies indicated that for routine screening application, the heterogeneity of the EMIT cannabinoid antibody may provide a distinct advantage and that the EMIT assay may be more sensitive than the other methods in detecting cannabinoid metabolites. Analysis of 496 urine samples using the EMIT Cannabinoid Assay suggested at least a casual use of marijuana by approximately 25% of the university student population studied.
A new tetracyclic antidepressant drug, maprotiline hydrochloride was found to be the agent of death in a 23-year-old subject following massive injestion (4.5-6.0 g). The case may be the first reported maprotiline death (sole cause) in the United States. Analytical parameters were studies and various chromatographic and spectrophotometric systems are reported. Quantitation was performed by gas-liquid chromatography using a nitrogen-phosphorous detector. Concentrations of the compound in biological fluids and tissues are also reported.
This case involves massive ingestion of disopyramide by a 19-year-old male, found dead, not having had the benefit of medical intervention. Quantitation of the drug was accomplished by gas chromatography using a flame ionization detector (GC/FID). Identification of the compound was done by thin layer chromatography (TLC) and ultraviolet spectrophotometry (UVS). The blood concentration of disopyramide was 15 times the usual therapeutic level and was easily detected by FID.
Succinylcholine, a bis-quaternary ammonium compound, is considered an elusive analyte due to rapid hydrolysis by pseudocholinesterase in plasma. However, tissue acetylcholinesterase is relatively inactive toward this substrate. Hence, analysis of tissues of succinylcholine-treated animals may reveal the presence of unchanged drug. This report describes three chromatographic techniques (TLC, GC/NPD, and GC/MS) which may be applied to the analysis of this substance in human tissues. Validation of the techniques was accomplished using tissues from rats treated with succinylcholine.