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Biomedical subjects

A C Hall

Publications and source records attributed to A C Hall.

77 records · Page 5Linked to original sources
PubMed1979

Intestinal metallothionein and the mutual antagonism between copper and zinc in the rat.

A study has been made of the mechanism of the mutual antagonism between copper and zinc in rats. Dietary zinc concentrations of up to 450 mg/kg had no effect on intestinal 64Cu absorption but 900 mg/kg caused a 40% reduction. This was associated with an increase in the mucosal uptake of 64Cu in the small intestine. This occurred mainly in the form of metallothionein and it appeared that copper displaced zinc from the protein after its synthesis had been induced by zinc. Ths intestinal absorption of 65Zn was decreased by 20% when the dietary copper intake was increased from 3 to 24 mg/kg. Further increases in copper intake to 300 mg/kg did not cause any additional decrease in 65Zn absorption or any change in the association of intestinal 65Zn with metallothionein. Concentrations of this protein in the intestinal mucosa were not influenced by dietary copper intake.

Animals↗
PubMed1972

Evidence of genetic heterogeneity in Huntington's chorea.

In an extensive study of Huntington's chorea in Queensland evidence was found to support an old observation that the magnitude of the variation in the symptom complex of the disease between different families is sufficient to suggest that there may be more than one form of Huntington's chorea allele present in the community. Analysis of data concerning age at onset indicates that at least two separate forms of the disorder may exist.

Adolescent↗
PubMedDate not supplied

Monitoring personal fine particle exposure with a particle counter.

Numerous epidemiological studies have demonstrated associations between ambient combustion-source particulates and adverse health outcomes. In order to better understand exposure to particles, we evaluated a portable particle counter for its ability to measure short-term peaks in personal particle exposure associated with various activities, such as proximity to vehicular traffic. In a series of laboratory and field measurements, a hand-held particle counter was evaluated by collecting simultaneous filter samples of particulate matter less than 2.5 microns (PM2.5) using a personal monitor. Time activity information was collected using a Personal Digital Assistant (PDA) which allows for linking of exposure events and particle measurements with 1 min temporal resolution. Laboratory and field experiments comparing the particle counter with the personal PM2.5 samples indicated low correlations (R2 < or = 0.39) for all size ranges. Despite these rather poor correlations, field measurements collected during different commuting modes (walking/cycling, car, bus, subway) and in different microenvironments indicated the ability of the particle counter to measure short-term particle exposures, especially those associated with combustion sources. Stratifying the measured particle counts by proximity to different particle sources enabled us to identify activities/microenvironments which were associated with higher exposures. Outdoor particle counts were significantly higher than indoor counts for particles smaller than 5.0 microns. Significantly elevated particle exposures were associated with proximity to environmental tobacco smoke (ETS), cooking emissions, wood smoke and with travel in vehicles powered with internal combustion engines.

Air Pollution↗