Biomedical subjects

R McMaster

Publications and source records attributed to R McMaster.

21 records · Page 2Linked to original sources

PubMed1975

Immunosuppression of normal lymphoid cells by serum from mice undergoing chronic graft-vs-host disease.

Spleen cells from F1 mice undergoing chronic graft-vs-host (GVH) reaction, induced by injection of parental cells, were shown to be immunosuppressed since their in vitro responses to the mitogens concanavalin A (Con A) and bacterial lipopolysaccharide (LPS) were substantially lower than control animals. Serum, from mice undergoing GVH, when cultured in vitro with normal spleen cells was immunosuppressive. The proliferation response to Con A and allogeneic cells of normal syngeneic, allogeneic, and parental spleen cells was 90% suppressed when serum from mice undergoing chronic GVH was added in comparison to the addition of serum from untreated F1 mice. Similarly, the in vitro antibody response to a T-dependent antigen was impaired; however, the antibody response to a T-independent antigen was not impaired. These results indicate that T cell functions are more sensitive than are B cell functions to immunosuppressive factors in the serum of mice undergoing GVH.

Animals↗

PubMed1971

Leucocyte ascorbic acid levels and vitamin C intake in older people.

Leucocyte ascorbic acid (L.A.A.) levels and vitamin C intake were measured in a random sample of men and women aged 62-94 years. L.A.A. distributions are positively skewed but log normal. L.A.A. mean values show no age difference in men but are significantly lower in older women. The mean value for all women (23.88mug/10(8) cells) is significantly higher than that for all men (18.11 mug/10(8) cells). L.A.A. values are significantly higher in both sexes in the six months July to December. Vitamin C intake distributions are positively skewed but not improved by log transformation. No significant age or sex differences were found except that a significantly greater proportion of men over than of those under 70 years have intakes less than 30 mg daily. Mean intake is significantly higher in men but not in women in the six months April to September, though in both sexes a significantly greater proportion have intakes less than 30 mg daily in October to March compared with April to September. Fifty per cent. of men and 58% of women have intakes less than 30 mg daily, 23.6% of men and 28.1% of women have intakes less than 20 mg daily, and 4.7% of men and 3% of women have intakes less than 10 mg daily. These percentages increase during the winter. A moderate correlation is present between vitamin C intake and L.A.A. level. L.A.A. levels increase in parallel with but lag behind seasonal increases in vitamin C intake.

Age Factors↗

PubMedDate not supplied

Distributed situation awareness in dynamic systems: theoretical development and application of an ergonomics methodology.

The purpose of this paper is to propose foundations for a theory of situation awareness based on the analysis of interactions between agents (i.e. both human and non-human) in subsystems. This approach may help to promote a better understanding of technology-mediated interaction in systems, as well as helping in the formulation of hypotheses and predictions concerning distributed situation awareness. It is proposed that agents within a system each hold their own situation awareness, which may be very different from (although compatible with) that of other agents. It is argued that we should not always hope for, or indeed want, sharing of this awareness, as different system agents have different purposes. This view marks situation awareness as a dynamic and collaborative process binding agents together on tasks on a moment-by-moment basis. Implications of this viewpoint for the development of a new theory of, and accompanying methodology for, distributed situation awareness are offered.

Awareness↗