Browsing by Author "Brink, P. A."
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- ItemA DNA polymorphism in the human low-density lipoprotein receptor gene(Health and Medical Publishing Group -- HMPG, 1986-07) Kotze, M. J.; Retief, A. E.; Brink, P. A.; Weich, H. F. H.A new restriction fragment length polymorphism (RFLP) in the low-density lipoprotein receptor gene is described using the Stu I restriction endonuclease and a cDNA probe. The frequency of the two RFLP alleles was determined in 60 unrelated white subjects and 11,70/6 of them were found to be heterozygous for the polymorphism. Mendelian segregation of the RFLP was found in 3 informative families. The possible use of the RFLP in the diagnosis of familial nypercholesterolaemia in South Africa is discussed.
- ItemLinkage disequilibrium between a marker on the low-density lipoprotein receptor and high cholesterol levels(Health & Medical Publishing Group, 1986-07) Brink, P. A.; Steyn, L. T.; Bester, A. J.; Steyn, K.We describe the presence of a linkage disequilibrium between high cholesterol levels in Afrikaner individuals and the common allele of the Pvu II restriction fragment polymorphism on the low-density lipoprotein (LDL) receptor gene. The frequencies of the common and the rare allele in a sample of the Afrikaner population were 0,654 and 0,346 (65 individuals) and 0,794 and 0,206 in the hypercholesterolaemic population (34 patients) (P < 0,05). This finding supports other evidence for a founder origin of the high frequency of familial hypercholesterolaemia among Afrikaners.
- ItemLinkage study of the low-density lipoprotein-receptor gene and cholesterol levels in an Afrikaner family : quantitative genetics and identification of a minor founder effect(Health & Medical Publishing Group, 1990) Brink, P. A.; Brink, L. T.; Torrington, M.; Bester, A. J.Overlap of clinical and biochemical characteristics between hypercholesterolaemia in members of the general population and familial hypercholesterolaemic (FH) individuals may lead to misdiagnosis. Quantitative analyisis of family data may circumvent this problem. A way of looking for an association between plasma cholesterol levels and restriction fragment length polymorphism markers (RFLP) on the low-density lipoprotein (LDL) receptor gene by using reference cholesterol distributions was explored. Linkage, with a logarithm of the odds (LOD) score of 6,8 at θ 0, was detected between cholesterol levels and the LDL receptor in an extended Afrikaner family. Two RFLP-haplotypes, one previously found in a majority of Afrikaner FH homozygotes, and a second, Stu I -, BstE II +, Pvu II +, Nco I +, were associated with high cholesterol levels in this pedigree.
- ItemMendelian-inherited heart disease : a gateway to understanding mechanisms in heart disease : update on work done at the University of Stellenbosch(Clinics Cardiv Publishing, 2009-02) Brink, P. A.; Moolman-Smook, J. C.; Corfield, V. A.The presence of founder effects in South Africa for many single-gene diseases, which include heart diseases such as progressive familial heart block types I and II, hypertrophic cardiomyopathy and the long QT syndromes, afforded us the opportunity to identify causal genes and associated mutations through genetic mapping and positional cloning. From finding the genes, the emphasis has shifted to elucidating how primary defects cause disease and recognising factors that could explain the often pronounced phenotypic variability seen in persons carrying the same inherited defect. In some of these diseases, sudden unexpected death has been a frequent occurrence in young, apparently healthy individuals who had not been aware that they had inherited an underlying risk. Herein, we review progress in identifying genes, mutations and risk factors associated with the diseases mentioned.
- ItemPlasma vitamin A, E, C and B6 levels in myocardial infarction(Health & Medical Publishing Group, 1987-5) Labadarios, D.; Brink, P. A.; Weich, H. F. H.; Visser, L.; Louw, M. E. J.; Shephard, G. S.; Van Stuijvenberg, M. E.ENGLISH ABSTRACT: Vitamin A, E, C and B6 status was studied in 30 patients with myocardial infarction and in 19 age- and sex-matched patients after elective surgery or trauma. Plasma levels of the four vitamins studied were low, remained low or decreased transiently in both groups of patients during the acute catabolic response phase, and began to return to normal after the third day from the start of the catabolic response. These changes in plasma levels are therefore neither of any special pathophysiological importance in nor specific to myocardial infarction.
- ItemProgressive familial heart block type II (PFHBII): a clinical profile from 1977 to 2003(Clinics Cardiv Publishing, 2004-06) Fernandez, P.; Corfield, V. A.; Brink, P. A.An evaluation of a 38-year-old Caucasian woman, who was referred to Tygerberg Hospital (Western Cape Province, RSA) with Wenckebach second-degree or possibly complete atrioventricular (AV) block that had progressed from first-degree AV block, identified a family history of the cardiac conduction system disorder progressive familial heart block type II (PFHBII). This prompted a retrospective clinical review of the subjects described in the original study, as well as additional family members who had not been examined in the original study. Progression of clinical features was observed, but more importantly, PFHBII was clinically redefined as an AV nodal disorder, which may progress to dilated cardiomyopathy (DCM).
- ItemRace and gender representation of hypertrophic cardiomyopathy or long QT syndrome cases in a South African research setting(Clinics Cardiv Publishing, 2007-10) Heradien, M; Goosen, A; Moolman-Smook, J. C.; Brink, P. A.We researched hypertrophic cardiomyopathy (HCM) and long QT syndrome (LQTS) as models for studying the pathophysiology of arrhythmias and hypertrophy, and in the process we have had the opportunity to compare local disease profiles with global patterns. We trawled our database entries over the past 20 years to identify all cases of heart muscle and arrhythmic disease. Among these, we separated the index cases from the rest of their family members, segregating for the relevant heart disease, so that numbers were not biased by family size, and analysed the race and gender composition of the HCM and LQTS sectors. The majority of HCM index cases (n = 5 90, 51.1% of HCM index cases) were of mixed ancestry (MA), with white Caucasian ancestry following closely behind with 74 cases (42.0%); only a few black African (n = 5 9, 5.1%) or I ndian/Asian (n = 5 3, 1.7%) cases were seen or referred. The LQTS index cases were almost exclusively white Caucasian (n = 5 36, 88% of LQTS index cases), with four cases (9.8%) of MA, one (2.4%) of Indian/Asian and none of black African descent. These race demographics did not fit the national demographics for South Africa as a whole. In contrast, in both groups, gender biases (slightly more male than female HCM cases, and a 0.4 ratio of males to females in LQTS) previously reported elsewhere appeared to be replicated in our database. Genetic bias is an unlikely explanation for the skewed demographics in our database; a more likely explanation relates to various missed opportunities to diagnose, missed diagnoses and misdiagnoses, as well as the real population drainage of our main referral centre in the context of a differentiated healthcare system.
- ItemStriving towards the ideal cardiac functional assessment strategy : the contribution of tissue Doppler, strain and strain rate imaging(Clinics Cardiv Publishing, 2007-11) Moolman-Smook, J. C.; Brink, P. A.In cardiac research, a major goal of prevention of catastrophic events by risk-factor management and earlier detection has, in recent years, led to a proliferation of imaging modalities, moving us from old-fashioned chest X-ray through increasingly sophisticated approaches such as magnetic resonance imaging (MRI) and multi-slice fast computer-aided tomography (CT) scanning. Today, we have the option of using a vast array of invasive and non-invasive approaches, with diverse technical underpinnings, to assess various, and often overlapping aspects of cardiac function. Tissue Doppler imaging (TDI) and the related applications of strain and strain rate imaging are new technologies that are now being evaluated in the realm of practical patient care, and the underlying principles remind us that cardiac contractility is a reflection of the integration of muscle fibre architecture, mechanics and metabolism. TDI is the first technology that allowed imaging of motion within the myocardial wall rather than that of the blood pool, and permits analysis of velocities and accelerations from ultrasonic scatterers in muscle.1 Since its inception, it has been used to evaluate both new cardiac functional parameters as well as conventional function; for some of these, TDI has proven the superior imaging modality, while for others it offers only incremental information over conventional approaches.