Biomedical subjects
Publications and source records attributed to S M Ross.
Iron deficiency anaemia in pregnancy is not a common problem among Black patients in the Durban area, and prophylactic iron supplements do not lead to an increase in haemoglobin values. Prophylactic iron therapy should give way to investigation and appropriate treatment of patients with low haemoglobin values.
A total of 232 Black antenatal patients was assessed in a cross-sectional study and a total of 80 in a longitudinal study. Trichomonas vaginalis infection occurred almost twice as frequently as Candida albicans infection. Neisseria gonorrhoeae infection was present in 10% of patients, and mixed infections were present in 34% of patients.
Crude brain homogenates and cerebral tissue slices from rats with cobalt metal implanted in right and left cerebral cortices were used to examine high- and low-affinity GABA transport. High-affinity GABA transport was maximally reduced to 34% of controls 7 days after cobalt implantation, a time that coincides with peak seizure activity in this model. Kinetic analysis of high-affinity GABA transport, using brain homogenates, revealed a significant change in Vmax 7 days after cobalt implantation. (Vmax = 446.4 +/- 26.2 pmol/mg prot./min, cobalt, versus 787.8 +/- 67.3, control). An analysis of the low-affinity system revealed no depression of Km or Vmax parameters. Administration of valproic acid at a concentration as high as 1 mM in vitro or a dose of 300 mg/kg in vivo had no effect on high- or low-affinity GABA transport. The results obtained from cobalt-treated rats provide additional evidence for an involvement of GABA in experimental epilepsy.
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Crude mitochondrial synaptosomal (P2) fractions were used to measure L-glutamate 1-decarboxylase (GAD) activity, and crude synaptic membranes were isolated from rat brains and used to determine gamma-aminobutyric acid (GABA) concentration and postsynaptic GABA receptor binding characteristics in rats with cobalt, copper, or glass implanted in right and left cerebral cortices. Copper was employed as a positive metal control because it elicits a morphological profile similar to that of cobalt but is non-epileptogenic. From tissue adjacent to the lesion, GAD activity was assessed by counting trapped 14CO2 liberated from [14C]glutamate and was reduced maximally to 25% of glass controls 7 days following cobalt insult, a period of peak seizure incidence. No reduction in GAD activity was observed 1 or 21 days after cobalt treatment or at any time period in copper-or glass-treated animals. A radioligand [3H]GABA receptor assay was utilized to determine GABA levels, postsynaptic receptor number (Bmax), and the affinity of the postsynaptic receptor for the ligand (KD) in tissue surrounding the lesion. GABA concentration was reduced maximally to 47% of glass controls 7 days following cobalt implantation. Scatchard plot analysis of tissue adjacent to the cobalt lesion revealed a significant increase in apparent receptor density (Bmax) to 200% of glass controls 7 days after bilateraL cobalt implantation (Bmax = 3.97 +/- 0.83 pmol/mg of protein, cobalt versus 1.36 +/- 0.17, glass control). Moreover, at 7 days, no change in kinetic parameters was noted after copper treatment. From days 7 to 21, the density (Bmax) of postsynaptic GABA receptors in cobalt-treated tissue appears to return slowly to glass control values. Results from the present study suggest that degeneration of the GABA pathway in the frontal cortex of the cobalt-epileptic rat occurs and, coupled with the increased Bmax, may represent a "denervation supersensitivity" phenomenon.
A total of 232 pregnant Black antenatal patients was examined to determine the clinical features of vaginal infection. There was no correlation between the symptoms and the infection. The finding of a 'strawberry' vagina was specific for Trichomonas vaginalis infection, for which a single dose of 1 600 mg metronidazole (Flagyl) was found to be a highly effective form of therapy.
Inflammatory changes in the extraplacental fetal membranes and subchorionic plate of the placenta are a common cause of perinatal mortality and morbidity in certain communities if associated with fetal pneumonia, and may also interfere with long-term psychomotor development. This latter complication is particularly likely to occur if there has been a moderate degree of hyperbilirubinaemia in the neonate. The pathway of infection is by ascent through the cervical os and the organisms involved are usually bacteria.
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The effect of diet supplementation throughout pregnancy on third-trimester amniotic fluid growth-supporting activity (GSP) was studied in 100 African women; 32 were given zinc supplementation, 22 each animal and vegetable supplements, respectively, and 24 served as control subjects. No difference in GSP was noted in any of the four groups, the majority of fluids (65%) being noninhibitory. Zinc levels in fluids from African women were much lower than those described for other population groups at corresponding periods of gestation. Although zinc levels in liquor rose following dietary zinc supplementation, these remained lower than values described in white patients. In vitro addition of zinc (up to 153 mu moles per liter final concentration) to 17 noninhibitory African liquors resulted in these fluids becoming inhibitory.
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Amniotic fluid infections manifested by an inflammatory response in the extraplacental membranes and subchorionic plate of the placenta are a common phenomenon thought to be due in most cases to ascending bacterial infections via intact membranes. Fatal spread to the fetus is much less common and more likely to occur in underprivileged communities. The probable reasons are nutritional deprivation in the mother or both, leading to production of a liquor with diminished ability to suppress bacterial growth. Zinc is one component of the antibacterial system but liquor levels of zinc vary widely and inconsistently with antibacterial activity. Dietary supplementation with zinc did not improve antibacterial activity of liquors in a population with diminished liquor antibacterial activity and large number of fatal infections. Other factors in the genesis of amniotic fluid infections may be interference with normal defence mechanisms as a result of coitus in late pregnancy and vaginal infections with Trichomonas vaginalis. Socioeconomic factors may play a role apart from their association with maternal nutrition, through diminished hygiene associated with insufficient use of water and insufficient availability and use of medical facilities.
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The effects of a short-term behaviorally-oriented assertion training program were evaluated with a sample of drug-abuse patients concurrently involved in an ongoing inpatient program. Assertion questionnaire and verbal performance data were obtained from both a treatment and a no-treatment group prior to and following 3 weeks of assertion training. The results indicated consistent and significant group differences on the verbal behavior variables, but not on the questionnaire data. The results also suggested that the assessment of assertion by situationally defined problem areas may be more accurate and sensitive to change than a more general definition and assessment of assertive behavior.
Eighty-five amniotic fluid from women of three racial groups in the third trimester of pregnancy were each tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Streptococcus faecalis, and Candida albicans. Seventy-six per cent of fluid samples from white patients were inhibitory, while the corresponding figures for Africans and Indians were 33 and 52, respectively. Of 19 African fluid samples tested against E. coli only, one proved inhibitory.
The bactericidal properties of amniotic fluid normally protect fetuses from late gestational infections by bacteria. Recently, such infections were found responsible for nearly a third of the perinatal deaths in Addis Ababa, Ethiopia. This prompted an analysis of the antimicrobial activity of amniotic fluid in patients in that city. The antimicrobial activity of fluid from 53 women, collected at term, was measured by a semiquantitative plate-count technique. Only one of the fluid samples was bactericidal, 12 were bacteriostatic, and 40 were noninhibitory to bacterial growth.
Obstructed labour was the second most common cause of perinatal death in Addis Ababa, Ethiopia, being responsible for 9.1 perinatal deaths/1000 births. Most obstructed labours were due to cephalopelvic disporportion. There was a ninefold increase in the perinatal death rate when the patients were anaemic but most perinatal deaths were due to delays in seeking available obstetrical care. Formal education of the patients had little influence on the death rates but the informal education that comes with prolonged urban residence had a markedly favourable effect. Use of prenatal medical services and adequate income also had a favourable influence.