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Biomedical subjects

J Thomas

Publications and source records attributed to J Thomas.

At least 793 records · Page 44Linked to original sources
PubMed1978

Normal and amblyopic contrast sensitivity function in central and peripheral retinas.

Contrast sensitivity functions (CSF's) for temporally modulated sine wave gratings were established at a variety of retinal eccentricities in three esotropic amblyopes with acuities in their amblyopic eyes of 20/50, 20/100, and 20/300. CSF's were shown to vary with eccentricity and the degree of amblyopia. In the 20/50 amblyope, reduced CSF's were confined to the higher spatial frequencies and to the central 5 degrees of the retina. Given greater acuity deficits (e.g., 20/100 and 20/300), CSF's were depressed over the entire spatial frequency range tested, with the effects intruding farther into the peripheral retina than for the 20/50 amblyope. In addition, the detection of the temporal as well as the spatial modulation was depressed in the CSF's of the observers with severe amblyopia.

Adult↗
PubMed1978

Primary myxedema heart disease.

A case of primary myxedema heart disease in an 84-year-old man is presented. His history and physical examination were typical of myxedema. Electrocardiographic changes showing generalized low voltage, nonspecific S-T segment and T-wave changes, and nodal rhythm are characteristic of the disease. The patient showed remarkable improvement after oral liothyronine (Cytomel) therapy.

Aged↗
PubMed1978

Health education research-a UK venture.

In recent years health education has striven towards the goal of becoming a research based discipline, and in doing so has borrowed techniques and theoretical frameworks from other, more established sciences. However, a combination of practical constraints and the limitations of borrowed theories have left those involved in health education with much fundamental work on research to be done. The "Better Health" campaign has attempted to deal with many health factors in an integrated way (still a somewhat unusual approach) but to date has adopted a fairly traditional evaluation design. The campaign will be modified in subsequent phases; for example, evening classes for adults are now being piloted and may well form a support network operating in conjunction with mass media work in the future. It is to be hoped that this challenge to evaluation strategies will be taken up and that not only detailed data but fresh thoughts on evaluation will be offered in following papers.

Attitude to Health↗
PubMed1977

The pathways of assimilation of 13NH4+ by the cyanobacterium, Anabaena cylindrica.

The principal initial product of metabolism of 13N-labeled ammonium by Anabaena cylindrica grown with either NH4+ or N2 as nitrogen source is amide-labeled glutamine. The specific activity of glutamine synthetase is approximately half as great in NH4+-grown as in N2-grown filaments. After 1.5 min of exposure to 13NH4+, the ratio of 13N in glutamate to 13N in glutamine reaches a value of approximately 0.1 for N2- and 0.15 for NH4+-grown filaments, whereas after the same period of exposure to [13N]N2, that ratio has reached a value close to unity and is rising rapidly. During pulse-chase experiments, 13N is transferred from the amide group to glutamine into glutamate, and then apparently into the alpha-amino group of glutamine. Methionine sulfoximine, an inhibitor of glutamine synthetase, inhibits the formation of glutamine. In the presence of the inhibitor, direct formation of glutamate takes place, but accounts for only a few per cent of the normal rate of formation of that amino acid; and alanine is formed about as rapidly as glutamate. Azaserine reduces formation of [13N]glutamate approximately 100-fold, with relatively little effect on the formation of [13N]glutamine. Aminooxyacetate, an inhibitor of transaminase reactions blocks transfer of 13N to aspartate, citrulline, and arginine. We conclude, on the basis of these results and others in the literature, that the glutamine synthetase/glutamate synthase pathway mediates most of the initial metabolism of ammonium in A. cylindrica, and that glutamic acid dehydrogenase and alanine dehydrogenase have only a very minor role.

Ammonia↗