S.M. Fletcher

Analysis of LSD in human body fluids by high-performance liquid chromatography, fluorescence spectroscopy and radioimmunoassay

A scheme of analysis is described in which the particular advantages of high-performance liquid chromatography (HPLC), fluorescence spectroscopy and radioimmunoassay (RIA) are exploited to the greatest effect. RIA affords a rapid and sensitive preliminary screening method, while the subsequent HPLC analysis using fluorimetric detection yields quantitative chromatographic evidence together with characteristic fluorescence spectra. Fractionation of samples by HPLC followed by RIA of the fractions gives further confirmation of the presence of LSD and its metabolites. The combined methodology has been applied to the analysis of LSD in body fluids for forensic and clinical purposes. Levels down to 0.5 ng of LSD per ml can be detected using the minimum of sample.

Insulin. A forensic primer

Abstract Insulin poses certain problems for the forensic toxicologist. This paper reviews the biochemistry of insulin and experiences in detection and interpretation of insulin residues in overdose and poisoning.

Urine Screening for Drugs by EMIT

Homogenous enzyme immunoassay (EMIT) reagents for the detection of amphetamines, benzodiazepines, cocaine metabolite, methadone, opiates and dextropropoxyphene in urine were evaluated using an automated clinical analyser. Reproducibility of analyses was excellent, specificity good, and interference from unrelated drugs and urine preservatives low. When used on a variety of case urine samples no false negatives were observed and several unexpected positive EMIT results were obtained. The reagents thus appear suitable for screening urine samples in forensic cases for these drugs.

A Combined High-Performance Liquid Chromatography and Immunoassay Method for the Analysis of Morphine, Codeine and their Metabolites in Biological Fluids

A high-performance liquid chromatography-immunoassay method for the analysis of compounds that cross-react in commercial morphine immunoassays (enzyme multiplied immunoassay technique and radioimmunoassay) is described. An initial separation of the cross-reacting compounds by high-performance liquid chromatography is followed by the collection of fractions of the eluate and either enzyme multiplied immunoassay technique or radioimmunoassay analysis of these fractions. This enables a chromatogram of the cross-reacting opiates to be constructed. By this method opiates such as morphine and codeine, as well as their metabolites, present in blood and urine, can be identified and quantified.

The fate of LSD in the body: forensic considerations.

The metabolism of LSD has been studied by analysing plasma and urine samples from Rhesus monkeys treated with radioactively labelled LSD. Plasma 14 C radioactivity reached a maximum value within one hour after treatment and declined over the following 23 hours. The 14 C radioactivity was detectable in the urine samples for up to 48 hours and fractionation by HPLC showed seven peaks of radioactivity, five of which cross-reacted in the RIA procedure.

The Production and Evaluation of an Antiserum for the Detection of Human Saliva

An antiserum raised in rabbits against human whole saliva cross-reacted with human serum and semen. Affinity chromatography of the antiserum on columns of immobilised human serum and seminal protein absorbed out these cross-reacting antibodies leaving a major antibody which reacted with α-amylase in saliva and pancreatic juice. The absorbed antiserum was evaluated as a reagent for the specific detection of human saliva in stains of forensic interest ; in a blind trial consisting of 87 samples, 32 positives, 1 false negative and no false positives were obtained. The antiserum appears to be highly specific for human saliva and does not cross-react with that of eight species of popular domestic animals.

Identification of Cardiac Glycosides in Human Body Fluids by a Combination of High-Performance Liquid Chromatography and Radioimmunoassay

A method for the identification and measurement of digoxin, β-methyldigoxin, lanatoside C and deslanoside in body fluids is described. It consists of a separation by high-performance liquid chromatography and subsequent assay of fractions of eluent by radioimmunoassay. The method has been used in cases involving poisoning by digoxin and lanatoside C.

Monoclonal Antibody: a Major New Development in Immunology

A recently developed technique—lymphocyte hybridisation—has made possible the isolation and large-scale culture of a single antibody-producing lymphocyte. The ‘anti-serum’ obtained in this way is a pure preparation of a single immunoglobulin species, and not a highly complex mixture as is present in conventional antisera. In this brief review we describe the technique and its product, and discuss some of its possible applications in forensic serology and toxicology.

Radioimmunoassay of cardiac glycosides in haemolysed blood: derivation of serum levels.

The effect of haemolysis on blood levels of the cardiac glycosides digoxin, β -methyl-digoxin, lanatoside C and deslanoside, were studied and conversion factors for deriving serum levels from haemolysed post-mortem blood levels were determined experimentally. These factors were not simply related to plasma/erythrocyte distribution ratios as it was found that haemolysis releases only part of the erythrocyte-associated glycoside in immunoassayable form.