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Biomedical subjects

A J McBay

Publications and source records attributed to A J McBay.

At least 19 recordsLinked to original sources
PubMed1987

Fatal verapamil poisoning.

A case of fatal verapamil poisoning is reported. The pathologic and toxicologic findings are discussed.

Aged↗
PubMed1985

Cannabis: pharmacology and interpretation of effects.

A selective introductory review of the Cannabis literature is presented. Subjects reviewed include the relative psychoactivities of Cannabis constituents, the disposition and distribution of THC and its metabolites, the relative psychoactivities of THC metabolites, and the use of cannabinoid concentrations in physiological fluids in interpretations of the significance of Cannabis-induced effects. The pharmacology of cannabinoids in humans is emphasized.

Arousal↗
PubMed1984

Ethanol, marijuana, and other drug use in 600 drivers killed in single-vehicle crashes in North Carolina, 1978-1981.

Although the use of ethanol, marijuana, and other drugs may be detrimental to driving safety, this has been established by direct epidemiological evidence only for ethanol. In this study, the incidences of detection of ethanol (and other volatile substances), delta-9-tetrahydrocannabinol (THC), barbiturates, cocaine and benzoylecgonine, opiates, and phencyclidine were determined in an inclusive population of 600 verified single-vehicle operator fatalities that occurred in North Carolina in 1978 to 1981. The incidence of detection of amphetamines and methaqualone were determined for drivers accepted for study during the first two years (n = 340) and the last year (n = 260), respectively. Blood concentrations of 11-nor-deta-9-tetrahydrocannabinol-9-carboxylic acid (9-carboxy-THC) were determined in THC positive drivers. EMIT cannabinoid assays were performed on blood specimens from all drivers accepted for study during the third year, and the feasibility of using the EMIT cannabinoid assay as a screening method for cannabinoids in forensic blood specimens was investigated. The incidence of detection of ethanol (79.3%) was far greater than the incidences determined for THC (7.8%), methaqualone (6.2%), and barbiturates (3.0%). Other drugs were detected rarely, or were not detected. Blood ethanol concentrations (BECs) were usually high; 85.5% of the drivers whose bloods contained ethanol and 67.8% of all drivers had BECs greater than or equal to 1.0 g/L. Drug concentrations were usually within or were below accepted therapeutic or active ranges. Only a small number of drivers could have been impaired by drugs, and most of them had high BECs. Multiple drug use (discounting ethanol) was comparatively rare. Ethanol was the only drug tested for that appears to have a significantly adverse effect on driving safety.

Accidents, Traffic↗
PubMed1982

Radioimmunoanalysis of delta-9-THC in blood by means of an 125I tracer.

A radioimmunoassay for delta-9-THC in plasma, whole blood, or hemolyzed blood specimens has been presented. Samples and standards were diluted with methanol and centrifuged. An aliquot of the supernatant fluid was incubated with RIA buffer, 125I-labeled delta-8-THC and rabbit anti-THC serum. Solid phase goat anti-rabbit immunoglobulins were added to separate bound from free THC. After centrifugation the supernatant fluid was aspirated and the radioactivity of the precipitate was counted in a gamma counter. The concentration of THC was calculated from a standard curve using the logit-log transformation of the average counts of duplicate tubes. The assay had several advantages. Methanol dilution gave better results than direct analysis. The 125I-labeled THC had high specific activity and could be counted in a gamma counter. The immunological separation of antibody-bound THC from free THC was better than separation techniques using ammonium sulfate and activated charcoal. THC was determined in 0.1 ml of sample with a sensitivity of 1.5 ng/ml in plasma and 3.0 ng/ml in hemolyzed blood.

Antibody Specificity↗
PubMed1982

Isopropanol and isopropanol deaths-ten years' experience.

A population of persons who were found, at death, to have significant levels of isopropyl alcohol (isopropanol) in their blood is described. The role of isopropanol in causing death is reviewed in 57 fatal cases. The contribution of acetone, the major metabolite of isopropanol, to death is assessed. Results indicate that mixed alcohol poisoning with ethanol and isopropanol suggests decreased production of acetone. Modalities for antemortem and postmortem detection of isopropanol are presented.

1-Propanol↗
PubMed1981

125I radioimmunoassay of delta-9-tetrahydrocannabinol in blood and plasma with a solid-phase second-antibody separation method.

In this sensitive and specific radioimmunoassay for delta-9-tetrahydrocannabinol, an iodinated tracer with high specific activity and a solid-phase separation are used. Within-run coefficients of variation for 5.0 and 30.0 microgram/L concentrations were 7.8 and 4.2% for plasma and 14 and 10.6% for hemolyzed blood specimens, respectively. Day-to-day coefficients of variations ranged from 7.3 to 13.6% (for 7.6 to 33.0 microgram/L concentrations) for plasma and 13.4 to 18.1% (3.0 to 52.1 microgram/L) for hemolyzed blood specimens. Data for time after start of smoking of a standard THC-containing cigarette vs the concentration of delta-9-tetrahydrocannabinol in the plasma were similar to those obtained by others. Positive plasma specimens from the smoking study were analyzed by gas chromatography-mass spectrometry and by our radioimmunoassay. Nonparametric statistical comparison and linear regression (r2 = 0.972) showed that results by the two methods of analysis correlate well. The sensitivity of the assay was at least 0.3 microgram/L for plasma, 1.1 microgram/L for hemolyzed blood.

Adult↗