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Biomedical subjects

J E Heveran

Publications and source records attributed to J E Heveran.

10 recordsLinked to original sources
PubMed1980

Determination of phencyclidine by radioimmunoassay.

A radioimmunoassay (RIA) was developed for measurement of phencyclidine (PCP) and its monohydroxy metabolites in urine. Anti-PCP serum was generated in rabbits and the labeled antigen was prepared by radio-iodination (125I) by the Hunter-Greenwood procedure. Adjustment of the antiserum and 125I-antigen concentrations resulted in a dynamic response from 0 to 200 ng/ml and as little as 2 ng/ml was detected. Reagents were stable for at least three months at 2 to 8 degrees C. Most (95%) urine specimens from presumed nonusers contained less than 5 ng/ml and urine specimens from suspected abusers usually exceeded 100 ng/ml. Comparison of RIA with other methods for detection of PCP showed good agreement. Cross-reactivity with other commonly prescribed drugs was not encountered. The recovery of PCP was 93 to 109% over the 20 to 175 ng/ml concentration range and the reproducibility (average coefficient of variation) was +/- 13%. Development of the RIA for PCP has resulted in a rapid procedure that can be adapted to automated processing and is also suitable for small-scale testing.

Animals↗
PubMed1978

Detection of barbiturates by latex agglutination inhibition.

A latex-agglutination inhibition test was developed and evaluated for the detection of barbiturates, primarily in urine, but it has applicability to serum. The 2-h test was performed with samples free of gross debris in a 37 degree C heat block and the reaction between the barbiturate antibody and the barbiturate-latex, at pH 7.3, was inhibited by urines containing secobarbital, amobarbital, pentobarbital, butabarbital, or phenobarbital. For laboratory standards the test was particularly sensitive to secobarbital (300 microgram/litre) and relatively insensitive to amobarbital (5000 microgram/litre). In clinical specimens some barbiturates were detected at levels as low as 150 microgram/litre. The test was specific, and negative endpoints were frequently noted in as little as 30 min. The effects of variables (antiserum dilution, urine specific gravity, heat block temperature, sample size, and type of barbiturate) on the degree of agglutination were also determined.

Agglutination Tests↗
PubMed1975

Automated constant-current coulometric assay system for ascorbic acid and sodium ascorbate.

The performance of an automated constant-current coulometric system for the assay of ascorbic acid and sodium ascorbate is described. After loading, it is capable of analyzing 25 samples and printing out the titer values with no operator attention for 2.5 hr. Under optimum conditions, ascertained by evaluating various electrochemical parameters, the accuracy and precision (95% ts) were found to be +/- 0.3%.

Ascorbic Acid↗
PubMed1975

Simultaneous detection of morphine and barbiturates in urine by radioimmunoassay.

This report describes a radioimmunoassay for the simultaneous detection of morphine and barbiturates. Morphine and barbiturate antibodies, obtained from goats, were mixed with 125l-labeled antigens. By adjusting concentrations of the morphine and barbiturate antibodies and radiolabeled antigens, closely superimposed standard curves for the two drugs would be obtained. As a consequence, similar response curves were obtained for urine specimens containing morphine or barbiturates. Although concentrations as low as 25 mug/liter could be measured, to ensure against false positive reactions the test should be performed at the 100 mug/liter concentration. Unknown samples positive by the dual assay were confirmed by separately testing the specimens with the individual radioimmunoassay specific for morphine or barbiturate. Equivalency tests of urines positive for morphine, positive for barbiturates, or negative for both demonstrated complete correlation between the single and dual assays. The mixed reagent retained its sensitivity and specificity for at least three months when stored at 4 or 25 degrees C. The dual radioimmunoassay is a rapid, simple procedure that can be adapted to automated processes and that is suitable for large- and small-scale screening.

Barbiturates↗