Biomedical subjects
Publications and source records attributed to W J Smith.
To assist in locating and quantifying fugitive emissions in a primary lead smelter, a "real time" lead-in-air analyzer has been developed. Dust is collected on paper tape filters and the lead analysed by X-ray fluorescence. The unit has been used successfully to assist in the implementation of an engineering control monitoring program.
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The difference between BP and USP rotating basket dissolution apparatus was investigated by applying both methods to a range of commercial formulations and the NCDA Performance Standard II. No significant differences were obtained between the two sets of apparatus for the commercial tablets. However appreciable difference was observed with the NCDA calibrator.
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The assumption that renal allograft histology should be perfectly normal during quiescence in the absence of rejection or nephrotoxic insults has not been adequately investigated. To study this, routine renal allograft biopsies were performed at approximately 1 and 4 weeks, when patients often had normal function or stable acute tubular necrosis (ATN). These were compared with biopsies from other patients during autologous ATN or clinically evident allograft rejection. There were two new findings: (1) Almost all biopsies contained an interstitial infiltrate, so that only the presence of vasculitis provided a clear distinction between rejection and quiescence. Most of the biopsies with infiltrates were from patients who had never received cyclosporine, so that an infiltrate does not necessarily signify toxicity due to this drug. (2) A major proportion of the cells in some biopsies appeared to express both the helper/inducer and the cytotoxic/suppressor phenotype, and a similar finding after in vitro stimulation suggests that this represents a cell population that is activated in some way.
Application of the British Pharmacopoeia (BP) Analytical procedure for the determination of leachable chromium to samples of catgut sutures yielded fading coloured solutions and was considered to constitute a poor basis for an analytical method. The United States Pharmacopeia (USP) method and an adaptation of the American Public Health Association (APHA) method were explored and found to give linear responses over the concentration range of interest. Both these methods were applied to a series of samples and the results obtained were different as the APHA method measures total chromium while the USP procedure determines only chromium (VI).
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The introduction of a new batch of feed to 400 pigs aged five to eight weeks resulted in 38 deaths and further morbidity associated with multiple haemorrhages. Signs abated within two days of withdrawal of the feed. Widespread haemorrhages were present in many tissues including the pancreas. Additional pancreatic lesions comprised focal necrosis, atrophy and fibrosis of exocrine tissue. The condition was reproduced experimentally in pigs and vitamin K protected mice against the injurious effects of the feed. The cause was not determined but it is speculated that more than one toxic factor and an imbalance of nutritional factors may have been present in the diet.
Experimental infections of canaries with an avian trypanosome, Trypanosoma bouffardi, isolated from West Africa demonstrated that these infections can cause pathological changes in tissues. Enlargement of the spleen coincided with peak parasitaemia but no other gross changes were observed. Histopathological examination of infected and control birds revealed focal myocarditis and lymphoid hyperplasia, in infected birds, which are consistent with trypanosome infection. Avian trypanosome infections are not usually regarded as pathogenic but our results suggest that pathological changes occur which are similar to those observed in mammals infected with salivarian trypanosomes.
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Nine laboratories participated in a collaborative study of a method for determining 6 nitrosamines, dimethylnitrosamine, diethylnitrosamine, dibutylnitrosamine, nitrosopiperidine, nitrosopyrrolidine, and nitrosomorpholine, in the 5-17 ppb range. The coefficients of variation for repeatability were 10.8, 8.5, 10.4, 8.5, 8.7, and 7.8% with corresponding coefficients of variation for reproducibility of 16.4, 12.0, 13.6, 10.8, 11.2, and 10.3% and recoveries of 89.6, 91.6, 84.7, 90.0, 89.6, and 88.1%, respectively. The method was adopted official first action.