Browsing by Author "Odendaal, Hein J."

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    Analysis of two mutations in the MTHFR gene associated with mild hyperhomocysteinaemia - heterogeneous distribution in the South African population
    (Health and Medical Publishing Group (HMPG), 2002-06) Scholtz, Charlotte L.; Odendaal, Hein J.; Thiart, Rochelle; Loubser, Lynzie; Hillermann, Renate; Delport, Rhena; Hayward Vermaak, W. J.; Kotze, Maritha J.
    Objective. The frequencies of mutations 677C→T and 1298A→C in the methylenetetrahydrofolate reductase (MTHFR) gene, previously shown to be associated with decreased enzyme activity that may lead to hyperhomocysteinaemia and consequently increased risk of cardiovascular disease (CVD), were determined in the South African population. Methods. HinfI (677C→T) and MboII (1298A→C) restriction enzyme analyses were performed on amplified DNA samples of 76 white, 73 coloured and 60 black subjects. Results. The mutant alleles of mutations 677C→T and 1298A→C were more common in the white (allele frequencies 0.36 and 0.37, respectively) than in the black population (0.04 and 0.09), while intermediate frequencies were detected ill the coloured population (0.18 and 0.30). Homozygosity for mutation 677C →T was not detected in the black cohort, while this genotype was detected in 1 coloured (1.4%) and 8white (10.5%) subjects. In the black population, 5% of the 60 subjects analysed were homozygous for mutation 1298A → C, compared with approximately 12% -in both the white and coloured populations.
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    Effects of Prenatal Exposure to Alcohol and Smoking on Fetal Heart Rate and Movement Regulation
    (Frontiers Media, 2021-07) Lucchini, Maristella; Shuffrey, Lauren C.; Nugent, J. David; Pini, Nicoló; Sania, Ayesha; Shair, Margaret; Brink, Lucy; Du Plessis, Carlie; Odendaal, Hein J.; Nelson, Morgan E.; Friedrich, Christa; Angal, Jyoti; Elliott, Amy J.; Groenewald, Coen A.; Burd, Larry T.; Myers, Michael M.; Fifer, William P.
    egative associations of prenatal tobacco and alcohol exposure (PTE and PAE) on birth outcomes and childhood development have been well documented, but less is known about underlying mechanisms. A possible pathway for the adverse fetal outcomes associated with PTE and PAE is the alteration of fetal autonomic nervous system development. This study assessed PTE and PAE effects on measures of fetal autonomic regulation, as quantified by heart rate (HR), heart rate variability (SD-HR), movement, and HR-movement coupling in a population of fetuses at ≥ 34 weeks gestational age. Participants are a subset of the Safe Passage Study, a prospective cohort study that enrolled pregnant women from clinical sites in Cape Town, South Africa, and the Northern Plains region, United States. PAE was defined by six levels: no alcohol, low quit early, high quit early, low continuous, moderate continuous, and high continuous; while PTE by 4 levels: no smoking, quit early, low continuous, and moderate/high continuous. Linear regression analyses of autonomic measures were employed controlling for fetal sex, gestational age at assessment, site, maternal education, household crowding, and depression. Analyses were also stratified by sleep state (1F and 2F) and site (South Africa, N = 4025, Northern Plains, N = 2466). The final sample included 6491 maternal-fetal-dyad assessed in the third trimester [35.21 ± 1.26 (mean ± SD) weeks gestation]. PTE was associated with a decrease in mean HR in state 2F, in a dose dependent fashion, only for fetuses of mothers who continued smoking after the first trimester. In state 1F, there was a significant increase in mean HR in fetuses whose mother quit during the first trimester. This effect was driven by the Norther Plains cohort. PTE was also associated with a significant reduction in fetal movement in the most highly exposed group. In South Africa a significant increase in mean HR both for the high quit early and the high continuous group was observed. In conclusion, this investigation addresses a critical knowledge gap regarding the relationship between PTE and PAE and fetal autonomic regulation. We believe these results can contribute to elucidating mechanisms underlying risk for adverse outcomes.
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    Lipoprotein(a) determination and risk of cardiovascular disease in South African patients with familial hypercholesterolaemia
    (Health & Medical Publishing Group, 2000) Scholtz, Charlotte L.; Lingenhel, Arno; Hillermann, Renate; Stander, Ilse A.; Kriek, Josef A.; Marais, Martelle P.; Odendaal, Hein J.; Kraft, Hans G.; Utermann, Gerd; Kotze, Maritha J.
    Objective. A raised plasma level of lipoprotein(a) (Lp(a)) is an established genetic risk factor for coronary heart disease (CHD), particularly in patients with concomitant elevation of low-density lipoprotein (LDL) cholesterol. The current study focused on the comparison of two commercially available Lp(a) assay kits to determine whether differences observed in measured Lp(a) levels could be deemed negligible in CHD risk assessment in familial hypercholesterolaemic (FH) patients. Design. To compare results obtained on duplicate plasma samples using two commercially available Lp(a) measuring kits, the immunoradiometric assay (RIA) and the enzyme-linked immunoabsorbent assay (ELISA). Setting. Division of Human Genetics, Department of Obstetrics and Gynaecology, University of Stellenbosch, Tygerberg, South Africa and the Institute for Medical Biology and Human Genetics, University of Innsbruck, Austria. Subjects. Plasma samples were obtained from 146 family members of 65 molecularly characterised South African FH families for comparative analysis. Results. Using the RIA method, 34 samples (23%) considered to be in the normal range by the ELISA technique, were placed in the high-risk group (> 30 mg/dl). Only one sample, considered to have a normal Lp(a) level with the RIA method, was categorised by the ELISA technique as high risk. Conclusion. Our data demonstrate that measurements of Lp(a) using the RIA method (the only assay available in South Africa at the time of this study) differ significantly from those obtained by the reference ELISA technique, suggesting that misclassification could lead to inaccurate CHD risk assessment. This is an important consideration in Afrikaner FH families, where plasma levels of Lp(a) have been shown to be elevated significantly in FH patients compared with non-FH individuals.
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    Psychosocial implications of stillbirth for the mother and her family : a crisis-support approach
    (Stellenbosch University, 2014) Human, Melanie; Groenewald, Coen; Odendaal, Hein J.; Green, Sulina; Goldstein, Richard D.; Kinney, Hannah C.
    In this article mothers’ emotions after experiencing a stillbirth are discussed. A study combining quantitative and qualitative research provided the foundation for a better understanding of the psychosocial implications of stillbirth for a mother and her family. The crisis-intervention approach was used to assist a control group of 25 mothers and was also evaluated during the study to establish the effectiveness thereof. Findings indicated that those mothers receiving the intervention used different coping mechanisms to deal with the severity of their loss. Narratives further show that relationship problems occurred following the loss. Receiving crisis intervention from a social worker during this period of grief, helped to facilitate the grieving process.
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    Stillbirth rates in singleton pregnancies in a stable population at Karl Bremer and Tygerberg hospitals over 50 years
    (Health & Medical Publishing Group, 2013-09-03) Odendaal, Hein J.; Gebhardt, G. Stefan; Theron, Gerhard B.
    Objectives. To determine the changes in stillbirth rates in singleton pregnancies in a stable population over a period of 50 years. Methods. Stillbirth rates for singleton pregnancies where the fetus weighed 1 000 g or more were collected from 1962 to 2011. From 1972 to 2011, rates included fetuses weighing 500 g or more at birth. Results. When the birth weight was 1 000 g or more the stillbirth rate declined from 70 to 12.6 per 1 000 births, and when the birth weight was 500 g or more it dropped from 34.2 to 24.5. The decline was very much slower towards the end of the study period. Conclusion. To achieve further sustained reductions in stillbirth rates, healthcare workers should continue to emphasise quality of healthcare, but they should also address and prevent specific conditions associated with stillbirth, such as smoking and drinking during pregnancy.