Browsing by Author "Gunston, Geney"

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    A dissection and angiographic study of anatomical variations in the anterior communicating artery complex in a South African sample
    (2024) Madolo, Mbalentle; Mpolokeng, Kentse; Gunston, Geney; More, Stuart
    The anterior communicating artery complex (ACAC) consists of the A1 and A2 segments of the anterior cerebral artery (ACA) and the anterior communicating artery (ACoA). The ACAC is said to be the most frequent site of aneurysms and anterior cerebral circulation variations. Clear correlation between cerebral arterial circulation variations and aneurysm development has been reported. Cerebrovascular diseases play a significant role in the causes of morbidity in South Africa. South African data in this area of research is currently lacking and thus more knowledge is needed. This study aims to report the prevalence of variations in the ACAC and their link to the prevalence of cerebral aneurysms. For the dissection portion of this study, a total of 68 (35 female and 33 male) adult formalin fixed brains were included. These brains were from the bodies that were previously dissected in the Department of Human Biology, University of Cape Town by the medical undergraduate and honours post-graduate students. For the ang
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    Anatomical study of the variation in the branching patterns and histology of the aorta in a South African population
    (2013) Da Silva, Rip; Gunston, Geney; Alexander, Rachel
    The documentation of variations in branching patterns of the aorta among South African populations is limited. Histological changes in the aortic wall have been documented and may be due to pathology and physiological processes. Whether these changes are solely due to physiological processes such as haemodynamics or pathology is yet to be determined. The present study aims to document the branching patterns of the aorta in a South African population and to distinguishing which particular histological changes in this vessel wall can be associated with haemodynamic forces rather than pathology. Seventy one cadavers from the University of Cape Town MBChB programme were used to document the branching pattern of the aorta. Twenty five random complete aortae with no evidence of macroscopic pathology were collected from Salt River Mortuary and used for histological examination. Seven sections (taken from branching and non-branching sites along the aorta) from each sample were stained with haematoxylin and eosin, alcian blue pH2.5 - periodic Schiff reaction and elastin von Gieson’s for histological analysis using a Zeiss Axioskop Mot upright microscope and Axiovision 4.7 software. Variation in the branching pattern of vessels along the length of the aorta was found in 49% of the cadaver sample. A variety of histological variations of the wall of the aorta in the mortuary sample was noted. Noteworthy variations include the abundance of acid mucopolysaccharide, the increased thickness of the tunica intima, and increased elastin fragmentation of the tunica media at branching sites of the aorta. A pronounced curved ridge-like structure was indentation on the luminal surface at the junction of the arch and descending aorta in 74% of the mortuary sample. The presence of this aortic ridge was association with younger aged individuals (Chi-square 4.57, p=0.56). A high frequency of gross variation in branching patterns of the aorta is present in this cadaver sample, including some rare patterns of variation. Clinically, knowledge of these variations would be relevant and useful to anatomists, radiologists and head, neck, thoracic and vascular surgeons. An explanation for the abundance of acid mucopolysaccharides may be the link between acid mucopolysaccharides and diet, however this needs further investigation. Altered haemodynamic forces created by turbulent flow at branching sites is proposed as the explanation for the increase in the thickness of the tunica intima and increased elastin fragmentation at the branching sites of the aorta, although other factors such as the effects of HIV in the vessel wall of this sample are yet to be determined. This study proposes that the aortic ridge is a result of the closure of the ductus arteriosus.
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    Towards understanding the quantitative literacy demands of a first-year medical curriculum
    (Health & Medical Publishing Group, 2011) Frith, Vera; Gunston, Geney
    Setting. When designing a medical curriculum, assumptions that are made about students' quantitative literacy (QL) competencies often lead to demands that students are unable to meet. In order to improve the match between the literacy demands of the curriculum and the literacy competencies of students, the demands need to be examined critically and the assumptions made explicit. Curriculum changes that reduce the articulation gap between demands and competencies are particularly important for broadening access and promoting success, in tertiary study, for students with disadvantaged educational backgrounds. Objectives. The objectives of this study are to survey the QL implicitly and explicitly contained in a course curriculum, in a manner that could be useful for the following purposes: raising awareness in health science lecturers of the nature and extent of the QL demands of their course materials, developing the theory relating to best practice for QL development in health sciences and informing the design of QL interventions. Method. We focus on the analysis of the QL competencies required of a student engaging with text-based learning materials in the curriculum of a first-year integrated human biology/epidemiology/biochemistry course. For the analysis we use a framework, which classifies quantitative material according to a mathematical and statistical dimension and a competencies dimension. Results and conclusions. A range of examples is presented which illustrate that the implicit QL demands of this first-year course curriculum are substantial and varied.
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    Understanding the experiences of students who enter the MBChB programme from educationally disadvantaged backgrounds and either succeed or fail in passing the first semester
    (2008) Gunston, Geney; Paxton, Moragh
    This qualitative study was conducted during 2005 in the Faculty of Health Sciences at the University of Cape Town. Drawing on the theoretical framework of the New Literacy Studies and, in particular, Gee's notion of Discourse acquisition, I sought to better understand the issues that impacted on success for students from educationally disadvantaged backgrounds who entered the MBChB programme.