Biomedical subjects

M Kogan

Publications and source records attributed to M Kogan.

21 records · Page 2Linked to original sources

PubMed1978

Radioimmunoassay of methaqualone in human urine compared with chromatographic methods.

The 125I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 microgram of methaqualone per liter of urine. The coefficient of variation was 2.88 +/- 0.39% interassay and 2.71 +/- 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P less than 0.001). Comparisons between the thin-layer chromatographic data and the gas-liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter two techniques. Gas-liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine.

Chromatography, Gas↗

PubMed1977

Evaluation of the radioimmunoassay for benzoylecgonine (a cocaine metabolite) in human urine.

The 125I-radioimmunoassay (RIA) for benzylecgonine (cocaine metabolite) in urine was evaluated by comparison with gas-liquid chromatography (GLC) and thin-layer chromatography (TLC) and the Enzyme-Multiplied Immunoassay Technique (EMIT). By RIA, a statistically significant concentration, 2 microng/liter, was observed for urinary benzoylecgonine. The coefficient of variation for the RIA was 2.58+/-0.38% inter-assay and 2.20+/-0.14% intraassay. There was cross-reactivity with cocaine (more reactive than benzoylecgonine) and other members of the tropane family of alkaloids. There was agreement between results by RIA and GLC in 95.5% of the samples, between RIA and TLC in 87.0%, and between RIA and EMIT in 84.5%. The percentage of true false-positives was 3.5% for the RIA in comparison to GLC, 8.8% in comparison to TLC, and 9.1% in comparison to EMIT. True false-negatives were insignificant (0 to 1.0%). GLC and RIA results correlated highly (phi=0.908). GLC, therefore, was the best comparison method for this evaluation study. RIA for benzoylecgonine is sensitive, reproducible, and reliable for the detection of cocaine in urine.

Chromatography, Gas↗

PubMedDate not supplied

Simplified approach to idiopathic toe-walking.

Controversy exists as to the treatment of idiopathic toe-walking (ITW). Since 1993, the authors have managed children with ITW using an outpatient percutaneous lengthening of the Achilles tendon, followed by placement of below-knee walking casts for 4 weeks. The authors reviewed 15 children who were treated for ITW with percutaneous Achilles tendon lengthening between 1993 and 1999. Ten of the 15 patients could be contacted for a follow-up survey. None of the parents stated that their child's toe-walking had recurred. There were no painful scars. All of the children were able to keep up with other children and did not notice any calf weakness. Two children had occasional Achilles tendinitis, which was relieved with antiinflammatory medications. All parents were satisfied with their child's outcome. The authors believe that percutaneous tendo-Achilles lengthening in ITW greatly simplifies the management of ITW.

Achilles Tendon↗