Biomedical subjects
Publications and source records attributed to D W Grant.
A review of the literature suggests that the right hemisphere compared with the left may be more sensitive to, and take longer to recover from, cerebral trauma. As there are also grounds for suggesting that shunting may be associated with limited cerebral insult, it is possible to conclude that, theoretically, left hemisphere shunting may be a preferable policy.
Right-hemisphere function was assessed in 28 hydrocephalic children by a colour-naming divided visual field task and a matching-to-sample manipulo-spatial task. A complementary word-naming divided visual field task was also administered. Comparisons with non-handicapped children revealed a visual processing deficit only. An interpretation of perceptual asymmetries in terms of differential hemispheric sensitivity and regional cortical thinning is advanced.
The morphology of Rhizopus oligosporus (NRRL 2710) sporangiospores and their physiological requirements for germination were studied. Germination proceeded in two separable phases: phase I (swelling) and phase II (germ tube protrusion). The optimal conditions for germination were 42 degrees C and pH 4.0. Sporangiospores contained insufficient endogenous carbon for swelling or germination to occur in distilled water. Initial swelling during phase I occurred only in the presence of a suitable carbohydrate. Subsequent production of germ tubes during phase II required exogenous sources of both carbon and nitrogen. Spores germinated most rapidly in mixtures of amino acids; l-proline and l-alanine were the most effective. These amino acids, at concentrations as low as 10 M, supported germination when combined with glucose and McIlvaine (citric acid-phosphate) buffer. d-Glucose, d-xylose, and d-mannose were the most effective carbohydrates tested for promotion of germination.
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Visual half-field asymmetries on a unilateral, monocularly presented tachistoscopic color-naming task for a 5- and a 7-year-old cohort were were remeasured after a 2-year interval and after a 1-year interval for a 10-year-old cohort. The curvilinear developmental trend observed on the first occasion of testing was fitted to a second-order polynomial equation, and this was used to predict mean laterality indices for each cohort on retesting. Null hypotheses were advanced that the mean values observed on retesting would not depart significantly from predicted means. These null hypotheses were upheld and an explanation of the curvilinear developmental trend in terms of changes in information-processing strategies is advanced.
An enzyme-linked immunosorbent assay (ELISA) was developed for the analysis of kojic acid in aqueous solutions and biological fluids. As little as 100 pg kojic acid ml-1 was detected in standard buffer. Analysis of biological fluids containing 1 mg kojic acid ml-1 showed that ELISA could detect the toxin at dilutions of 10(-4) in urine, deporteinated plasma, or serum. Urine and plasma samples collected form rabbits dosed intravenously with 56 mg kojic acid kg-1 body weight gave positive tests at dilutions of 10(-4). The immunoassay described may be used for detection of kojic acid produced during experimental or clinical aspergillosis.
5-, 7-, and 10-yr.-old children were tested on a lateralized color-naming task, the colors being presented unilaterally and monocularly. Each age group was composed of 20 boys and 20 girls. A significant effect of age was found, with the greatest perceptual asymmetry (a significant left visual-field effect) being observed for the 5-yr.-old group, and the smallest perceptual asymmetry for the 7-yr.-old group.
Visualization of aflatoxin deposits within Aspergillus parasiticus ATCC 15517 hyphae was made possible by using an enzyme-linked immunocytochemical technique.
An enzyme-linked immunosorbent analysis (ELISA) permitted the detection of less than 10 pg of aflatoxin B1 per ml. The antitoxin was most specific for aflatoxins B1 and B2alpha, and least specific for aflatoxin G1.
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