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Biomedical subjects

W J Nicholson

Publications and source records attributed to W J Nicholson.

71 records · Page 4Linked to original sources
PubMed1975

Mortality experience of a cohort of vinyl chloride-polyvinyl chloride workers.

These data are derived from early follow-up of individuals exposed for 5 or more years to vinyl chloride in a polymerization facility. At least 17 percent of the deaths that occurred were causally related to exposure to vinyl chloride. Longer periods of observation are required to provide information concerning the full spectrum of vinyl chloride-induced malignancies and their incidence among exposed workers. These data speak for the need to prevent exposure to vinyl chloride and for surveillance and early disease detection of those who have experienced vinyl chloride exposures in the past.

Adult↗
PubMed1974

Analysis of amphibole asbestiform fibers in municipal water supplies.

Details are given of the techniques used in the analysis of asbestiform fibers in the water systems of Duluth, Minnesota and other cities. Photographic electron diffraction and electron microprobe analyses indicated that the concentration of verified amphibole mineral fibers ranged from 20 x 10(6) to 75 x 10(6) fibers/l. Approximately 50-60% of the fibers were in the cummingtonite-grunerite series and 20% were in the actinolite-tremolite series. About 5% were chemically identical with amosite. A wide variety of analytical techniques must be employed for unique identification of the mineral species present in water systems.

Asbestos↗
PubMed1972

Brain amine concentrations after monoamine oxidase inhibitor administration.

The concentrations of 5-hydroxytryptamine (5HT), noradrenaline, and dopamine were estimated post mortem in brain stem, hypothalamus, and caudate nucleus in 33 patients who had been treated with isocarboxazid, clorgyline, or tranylcypromine and 11 controls. Similar and highly significant increases in 5HT and noradrenaline concentration occurred with all three drugs. The distribution was unimodal, but about a quarter of the patients showed only a small increase in brain amines. Tranylcypromine seemed to have a significantly greater effect on dopamine in caudate nucleus and hypothalamus compared with isocarboxazid and clorgyline. In the doses used chlorpromazine did not reduce the amine concentrations. Four patients with Parkinson's syndrome had low concentrations of dopamine in caudate nucleus in spite of monoamine oxidase inhibitor administration.

Aged↗
PubMedDate not supplied

Neurobehavioral changes among shipyard painters exposed to solvents.

Painters in three shipyards, exposed to a wide variety of solvents, were examined. A short battery of performance tests, a detailed occupational history, and a special questionnaire to assess acute (prenarcotic, transitory) and chronic (persistent) neurologic symptoms was administered. The results of the neurobehavioral performance tests demonstrated decrements in central nervous system function in painters when compared with a control group matched for age, sex, race, and education. The prevalence of reported acute neurological symptoms among painters was increased significantly compared to other occupational groups in the same yards; for chronic, persistent symptoms the difference was not statistically significant. Performance test scores were significantly, negatively correlated with chronic symptoms but not with acute symptoms. No significant correlations between performance test scores and duration of solvent exposure or between symptoms and duration of solvent exposure were observed. The reversibility of such symptoms and of decrements in central nervous system function after cessation of exposure is still uncertain.

Acute Disease↗
PubMedDate not supplied

Neurobehavioral assessment of Mohawk Indians for subclinical indications of methyl mercury neurotoxicity.

A total of 200 male and 200 adult female Mohawk Indians were examined by means of performance tests as part of a total health evaluation of participants in a medical field survey on the St. Regis Reserve. Age-corrected performance test scores were studied in relation to blood, urinary, and hair methyl mercury (MeHg) levels, and local fish consumption. Males were found to eat more fish than females and had relatively higher MeHg levels than females. Blood and hair MeHg levels were significantly correlated with local fish consumption for both sexes. Biological indicators of MeHg absorption suggested low exposure levels but did not correlate significantly with performance test scores. These findings indicate that the time of examination, St. Regis residents were exposed to almost "background" levels of MeHg and did not exhibit either subclinical or clinical manifestations of MeHg neurotoxicity.

Adult↗
PubMedDate not supplied

Recent data on cancer due to asbestos in the U.S.A. and Denmark.

The Authors present data, from the USA and Denmark, dealing with the carcinogenicity of chrysotile. This review considers epidemiological studies on the incidence of bronchogenic carcinoma and mesothelioma in populations exposed to commercial chrysotile and to mixtures of chrysotile and commercial amphiboles, with which the chrysotile is often contaminated. The analyses demonstrate that the risk of lung cancer is similar for chrysotile, amosite and crocidolite on a fiber exposure basis. Chrysotile and amosite appear to produce equal mesothelioma risks. The risk of mesothelioma is four to ten times greater for crocidolite.

Asbestos↗