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Biomedical subjects

W J Hunter

Publications and source records attributed to W J Hunter.

47 records · Page 3Linked to original sources
PubMed1980

Scientific aspects of the work of the Commission of the European Communities on Asbestos.

The Commission of the European Communities has been carrying out scientific investigations on asbestos for some years. The principal activity has been the regular meetings of two European Communities panels of scientific consultants concerned primarily with the pathology of the asbestos-related diseases, asbestosis and mesothelioma. In addition, the Commission has carried out a number of comparative studies on the measurement of asbestos in various media, using both gravimetric and microscopic techniques.

Air Pollutants, Occupational↗
PubMed1979

Intercomparison study on the determination of single administration toxicity in rats.

In 1977, the Commission of the European Communities initiated an intercomparison study to determine the single administration oral LD50 value in rats of each of 5 chemicals with the aims of comparing experimentation technologies, determining the degree of variation in the results and the various parameters used to establish the LD50 value, and establishing a common protocol for the determination of the LD50 value. Sixty-five laboratories in 8 countries took part in the first study. The significant variation in protocol may have led to the large interlaboratory variation observed in the results. Therefore, participating laboratories carried out a second study using a common protocol, preceded by a pilot study. A total of 100 laboratories in 13 countries participated. A majority of results of the second study are currently being analyzed, and the indications are that the interlaboratory variation has been significantly reduced.

Animals↗
PubMed1976

Biohydrogenation of unsaturated fatty acids. Hydrogenation by cell-free preparations of Butyrivibrio fibrisolvens.

Hydrogenation of cis-9,trans-11-octadecadienoic acid to yield trans-11-octadecenoic acid by cell-free preparations of Butyrivibrio fibrisolvens has been obtained under strictly anaerobic conditions. Reduced methyl viologen, NADH, and an endogenous electron donor each can serve as a reductant. Inhibition studies and gel filtration patterns reveal the presence of at least two hydrogenation systems, one of which is coupled through a flavin, possibly FMN. Although the enzymes comprising the biohydrogenation pathway, the fatty acid reductases and linoleic acid isomerase, are part of the bacterial membrane, they do not appear to be constituted as a multienzyme complex.

Cell-Free System↗
PubMed1975

Role of pectic and cellulolytic enzymes in the invasion of the soybean by Rhizobium japonicum.

Past workers have suggested pectic enzyme involvement in the invasion of legumes by Rhizobium. However, no role for pectic acid, pectin, or methyl cellulose depolymerase enzymes in the invasion of R. japonicum was suggested by the current study. Seedling inoculation with infective bacteria did not result in increased enzyme activity. Rhizobium japonicum cell-free culture extracts and 3-indoleacetic acid did not affect the activation, induction, or binding of these enzymes.

Cell-Free System↗
PubMed1973

Simple method for culturing anaerobes.

A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO(2). Gentamicin sulfate (50 mug/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use.

Anaerobiosis↗
PubMedDate not supplied

Importance of ulceration of carotid plaque in determining symptoms of cerebral ischemia.

In order to investigate the relationship between carotid plaque morphology and symptoms of cerebral ischemia, a prospective clinicopathological study was performed. Ninety consecutive intact carotid plaques obtained from surgery and 43 carotid plaques from cadavers without symptoms of cerebral ischemia were evaluated. Ulceration and mural thrombus were the only morphologic findings statistically correlated to the presence of hemispheric symptoms (p less than 0.02). Intramural hemorrhage was more common in patients with hemispheric symptoms but this difference was not statistically significant (p = 0.31). Plaque causing high degree stenosis had a higher incidence of intramural hemorrhage (p = 0.04) and ulceration (p less than 0.02). Ulceration of plaque plays a major role in the onset of hemispheric symptoms. The results of our study support the hypothesis that in the majority of the cases, hemispheric symptoms are embolic in nature.

Arteriosclerosis↗