Browsing by Author "De Graaf, A. S."
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- ItemStandards for the assessment of visual evoked potentials in an ethnically heterogeneous adult population(Health and Medical Publishing Group -- HMPG, 1985-02) De Graaf, A. S.; Lombard, C. J.; Hart, G. L.Visual evoked potentials (VEPs) were recorded by chequerboard pattern-reversal stimulation in 276 normal adult subjects aged 15-73 years. The sample comprised comparable white, coloured and black groups of both sexes. Significantly shorter latencies of the major positive component were found in both male and female black subjects compared with those in whites. No significant differences were found between the amplitudes in the different population groups, but females in each population group showed significantly higher amplitudes of the major positive component than males. There was a close relationship between latency and amplitude for both right and left eyes. Except in coloured females, a nonlinear relationship of the major positive component with age was demonstrated, the shortest latency being at about 35 years of age. It is suggested that the following criteria be used in the evaluation of VEP recordings: latency as well as the difference between latencies and amplitudes of the two sides of the major positive component (P1) as compared with standardized values for ethnic, sex and age groups.
- ItemA study of a family with inherited disease of cardiac and skeletal muscle. Part II. Skeletal muscle morphology and mitochondrial oxidative phosphorylation(Health and Medical Publishing Group -- HMPG, 1981-03) Lochner, A.; Hewlett, R. H.; O'Kennedy, A.; Van der Walt, J. J.; Tiedt, F. A. C.; Hoffman, H.; De Graaf, A. S.; Przybojewski, J. Z.; Torrington, M.Skeletal muscle morphology and mitochondrial oxidative phosphorylation capacity were examined in a family whose members showed varying combinations of mental subnormality, cardiomyopathy and muscle weakness. Light and electron microscopic findings suggested a neuropathic process, while tests of mitochondrial function indicated a state of tight coupling of oxidative phosphorylation, a feature in marked contrast to those in biochemical studies so far reported.
- ItemA study of a family with inherited disease of cardiac and skeletal muscle. Part III. Genealogical considerations and associations with low intelligence(Health and Medical Publishing Group -- HMPG, 1981-03) Torrington, M.; Przybojewski, J.,Z.; Hoffman, H.; De Graaf, A. S.; Hewlett, R.; Lochner, A.; O'Kennedy, A.; Tiedt, F. A. C.; Van der Walt, J. J.A family with inherited cardiac and skeletal muscle disease was also found to have members with low intelligence. The effects of social and environmental conditions upon the behaviour of family members are described, with particular attention to the sociomedical problems created by the combination of a hereditary disease and low intelligence.