Inter-laboratory evaluation of the bioluminescent Salmonella reverse mutation assay using 10 model chemicals.

We have developed the bioluminescent Salmonella reverse mutation assay as a tool for detecting mutagenicity applicable for high-throughput screening of new chemicals. In this study, we report the inter-laboratory evaluation of the assay using 10 model chemicals in five independent laboratories located in the USA (Groton, CT; Cambridge, MA and La Jolla, CA), Europe (Sandwich, Kent, UK) and Asia (Nagoya, Japan). The studies were performed in blinded fashion in all sites except for Groton and Cambridge laboratories. The chemicals were tested in at least three independent experiments using strains TA98-lux and TA100-lux in the presence and absence of metabolic activation. The results were statistically evaluated and compared to published results. Seven of the 10 compounds were positive in either TA98-lux and/or TA100-lux in the presence or absence of metabolic activation. The positive compound set included: nitrofurazone, 3-3'-dimethoxybenzidine, benzo[a]pyrene, 1,4-benzoquinone dioxime, 2-amino-5-nitrophenol, 2-bromo-4,6-dinitroaniline and busulfan. The remaining three compounds, namely, anthracene, crystal violet and benzyl chloride were negative in both Salmonella strains. Final results for individual compounds yielded 100% agreement among the laboratories and published data. Detailed comparison of all 40 individual test conditions yielded 93% (37 of 40) agreement among participating laboratories. We conclude that the bioluminescent Salmonella reverse mutation assay is a robust, accurate and economical higher throughput assay applicable for the mutagenicity screening of chemicals.

Evaluating a nurse-led DXA scanning service.

AIM: To examine the feasibility of using a peripheral dual energy X-ray absorptiometry (DXA) scanning service in a nurse-led clinic and whether or not it would influence treatment and clinician satisfaction with the service. METHOD: A nurse-led clinic, using peripheral DXA scans to identify patients at risk of osteoporosis, was established in the rheumatology department of the hospital. Patients were referred from several sources. A questionnaire was sent to referring health professionals with each scan result. Returned questionnaires were statistically analysed. Of the sample size of 2000, 1024 questionnaires were returned, giving a response rate of 51 per cent. RESULTS: The results confirmed the hypothesis that a nurse-led peripheral DXA scanning service is feasible and beneficial to referring clinicians. Eighty nine per cent (n=912) of respondents stated that the scan results influenced treatment of patients. CONCLUSION: Further investigation of the extent that the DXA scanning service may have reduced unnecessary treatment is required.