Saliva is an excellent analytical matrix for the detection of illicit drug residues such as tetrahydrocannabinol and amphetamine. Analysis of drugs in saliva offers significant advantages compared to blood or urine. These include ease of sample collection, reduced sample processing and greater accessibility for collection. However to fully exploit its potential knowledge of the physiology and of saliva, salivary drug metabolism, optimal collection strategies, rapid, sensitive and specific assays and possible interferences is required. The method selected for sample collection can also have a significant impact on the validity of the testing method. This review critically analyses these factors, the current approaches used and potential future developments in salivary drug analysis.

No abstract

A modified colorimetric enzyme-linked immunosorbant assay (ELISA) for Salmonella detection was compared to the standard culture method of the Bacteriological Analytical Manual/Association of Official Analytical Chemists (BAM/AOAC) using 20 artificially contaminated foods (1,200 test samples). The modifications to the current methodology consisted of an elevated incubation temperature of 42°C for the tetrathionate selective broth and M-broth postenrichments, as well as addition of 10 μg/ml novobiocin to the M-broth. The microtiter plate as not agitated during assay incubation, and centrifugation steps were eliminated from the protocol. This modified ELISA method was at least as productive as the standard AOAC culture method for the food samples tested. No false-positive reactions were encountered. The false-negative incidence was 1.5% for the immunoassay and 5.3% by the AOAC cultural method. The incidence of agreement between the methods was 96.7%.

1. The objective of the study was to determine the effect of temperature reduction on the response of rat skeletal muscles to myotonia-inducing agents. 2. A model myotonia was induced in the muscles in vitro, using either the chloride channel blocker anthracene-9-carboxylic acid or chloride-free Krebs solution. This model is similar in its characteristics to the myotonia which occurs in autosomal recessive generalized myotonia congenita in humans. 3. Isometric twitch contractions were recorded in the muscles in Krebs solution before and after the addition of the myotonia-inducing agent. The presence of myotonia was confirmed when the half-relaxation time of the twitch contraction after the addition of the agent was significantly greater than that before its addition. 4. Recordings were made at 37 degrees C, 30 degrees C, 25 degrees C and 15 degrees C. Myotonia developed at 37 degrees C, 30 degrees C and 25 degrees C, but not at 15 degrees C, indicating that at a temperature between 25 degrees C and 15 degrees C, anthracene-9-carboxylic acid-induced myotonia failed to develop. This supports the results obtained in humans suffering from myotonia congenita where myotonic contractions in the adductor pollicis muscle disappeared when the muscle temperature was cooled to 20 degrees C. 5. The myotonia which developed at 37 degrees C could be significantly reduced by exposure to 1 x 10(-4) mol/l ouabain or by elevation of the K+ concentration of the Krebs solution to 7.5 mmol/l. 6. Measurements made using microelectrodes showed that the conditions under which myotonia either did not develop or was significantly reduced, i.e. a temperature of 15 degrees C, exposure to 7.5 mmol/l K+ at 37 degrees C or exposure to 1 x 10(-4) mol/l ouabain at 37 degrees C were each associated with membrane depolarization. The results are discussed in terms of a possible role for depolarization in preventing/reducing the myotonic response.