Browsing by Department "Department of Human Biology"

Now showing 1 - 20 of 397
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    3D cine DENSE MRI: ventricular segmentation and myocardial stratin analysis
    (2013) Auger, Daniel A; Spottiswoode, Bruce S
    Includes abstract. Includes bibliographical references.
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    A new class of stem cells in South Africa: iPS cells
    (2013) Ballo, R; Greenberg, L J; Kidson, S H
    Created from adult rather than embryonic cells, induced pluripotent stem (iPS) cells represent a breakthrough in stem cell science, and their pioneers have been recognised with the 2012 Nobel Prize in Medicine. These cells offer new hope in the treatment of pathogenetic diseases, but there is still a way to go on the road to effective therapeutic applications.
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    A pilot study to identify links between genetic variation and shoulder pain and dysfunction after breast cancer radiotherapy
    (2021) McLarty, Callum; Shamley, ‪Delva; September, Alison
    Introduction – Treatment for breast cancer is associated with a risk of chronic shoulder and upper limb morbidity in up to 30% of patients. There is currently no consensus for the possible reason for this often repeated finding in the literature. Previous research has suggested that development of fibrotic tissue in response to cancer treatments such as surgery and radiotherapy could be an underlying cause of musculoskeletal dysfunction and pain. This study investigated if any genetic variants in several key fibrosis-modulating genes could be shown to be associated with risk of upper limb musculoskeletal dysfunction and pain in breast cancer survivors. Participants and Methods – A cross sectional study design was employed, using a candidate gene approach. A total of 326 South African breast cancer survivors were recruited from a tertiary hospital in the Western Cape (343 total, minus 17 samples with insufficient data collected). Each participant was scored for symptom severity using the shoulder pain and disability index (SPADI) questionnaire. Participants were then grouped for symptom severity using low, med or high SPADI scores. The low SPADI group served as controls (controls n=273, cases n=70). Participants were invited to donate a blood sample from which DNA was extracted. Each DNA sample was genotyped at seven polymorphic sites; three in TGF-ß, two in ATM, one in SOD2 and one in XRCC1, using PCR technologies and TaqMan allelic-discrimination probes. The resultant genotypes were analysed using multivariate analysis, including inferred haplotype analysis to search for association to shoulder pain and morbidity after treatment. A logistic regression analysis was also performed to investigate the association between SPADI score and age of participant. Results – When participant age was compared with symptom severity, it was found that younger participants were more likely to have moderate-to-severe symptoms than older participants. There was a significant difference in the minor allele frequencies between case and control groups for the rs4880 (C>T, SOD2) polymorphism. The T allele was present more in the case group than in controls, with minor allele frequencies of 0.67 vs 0.55 respectively. No other independent associations were noted for any of the remainder variants tested. When haplotypes were inferred for genes SOD2 and ATM, combinations between the rare alleles at rs4880 and rs1800058 (C>T, ATM) were associated (F=4.35, pT and ATM rs1800058 is recommended for further study, in addition to the rs4880 polymorphism in SOD2. These novel results are suggesting that there may be an association between fibrotic genes and the development of upper limb sequelae after treatment for breast cancer. A larger case-control study would be required to validate and explore these findings.
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    A sleep behaviour intervention to improve cardiometabolic health in adults with overweight and obesity
    (2020) Henst, Rob HP; Rae, Dale E; Roden, Laura C
    Rob Henricus Petrus Henst was born on the 12th of March in Schaijk, the Netherlands. He graduated from pre-vocational secondary education (VMBO) in 2005 and continued to study process and laboratory technology at an intermediate vocational educational (MBO) institution. In 2009, Rob started with a Bachelor of Science degree, majoring in Life Science with a minor in Exercise Science. For his undergraduate thesis in 2012, he moved to South Africa where he was introduced to chronobiology in exercise science. In 2013, Rob continued to study in South Africa for his Master of Science (Exercise Science) degree and published his first peer-reviewed article in the Journal of Biological Rhythms. He then developed an interest in sleep and cardiometabolic health, specifically in the context of public health. In 2015, these interests were combined and lead to his current PhD thesis on a sleep behaviour intervention for the betterment of cardiometabolic health. In this year, he also co-founded the business unit Sleep Science within the Sports Science Institute of South Africa to help individuals sleep better. In 2019, Rob moved back to the Netherlands to write the final pages of his PhD thesis.
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    A structured light solution for detecting scapular dyskinesis
    (2018) Verster, Jaco; Gray, Janine; Sivarasu, Sudesh; Mutsvangwa, Tinashe
    Scapular dyskinesis is a common occurrence in overhead athletes, i.e. athletes who participate in any sport where the upper arm and shoulder is used above the athlete’s head. However, no consensus has been reached on how to evaluate scapular dyskinesis quantitatively. In this thesis, we developed a measuring tool that can be used to evaluate certain key clinical parameters specific to scapular dyskinesis. The tool employs a 3D structured light computer vision approach to create a surface map of the soft-tissue across the scapula. This surface map is then analysed using surface curvature analysis techniques to identify the key clinical parameters associated with scapular dyskinesis. The main advantage of this method is that it provides a measurement tool that may facilitate future quantitative analysis of these key parameters. This may aid with diagnosis and monitoring of the condition by allowing measurement data to be collected both before and after treatment and rehabilitation. We expect that this tool will make the monitoring of treatment effectiveness easier while contributing to diagnostic computer vision.
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    A study comparing the effects of vincristine with those of ionizing radiation on the root meristem of Vicia faba
    (1972) Haddad, Dawne Merle
    Vincristine and vinblastine, two closely related alkaloids are extracted from the Madagaskar Periwinkle, Vinca rosea Linn. They have been shown to be effective oncolytic agents and cause arrest of mitosis at the metaphase stage, similar to that of colchicine andcolcimid. Clinically, vincristine has been found to produce a complete remission in patients with acute leukaemia. Tumour regression in patients with Hodgkin's disease, lymphosarcoma and certain childhood solid tumours have also been reported.
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    A study of the response of the root meristem of maize to fractionated and protracted doses of ionizing radiation
    (1971) Hering, Egbert Raymond
    Vicia faba and investigating the effects of ionizing radiation on its root system. In particular, species such as Tradescantia, Pisum, Allium and Mordeum vulgare have been extensively studied. Nevertheless an ever-increasing number of workers have used Vicia faba for explaining the basic problems of radio biology. One of the reasons is the small number of large chromosomes contained in the root meristem cells, which are particularly conducive to simple cytological analysis. The seedlings also have other attractive features.
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    A study on the role of oxidative stress and protein kinase signalling in hyperglycaemia induced cardiac remodelling
    (2023) Amtha, Nikhil; Gwanyanya, Asfree
    Background Almost one-third of all deaths in patients with uncontrolled diabetes mellitus and hyperglycaemia are due to cardiovascular diseases. Chronic exposure of the heart to hyperglycaemia leads to a maladaptation called pathological cardiac remodelling and occurs via oxidative stress due to excess production of reactive oxygen species (ROS). In the heart, ROS modulates cardiac differentiation, cardiomyocyte proliferation, and myocardial tissue growth via ROS-sensitive protein kinases such as the mitogen-activated protein kinase (MAPK). Although there are several different MAPKs, the p38 MAPKs are involved in cardiogenesis and implicated in stimulating myocyte apoptosis, hypertrophy, or even antiapoptotic effects. As such, the role of p38 MAPKs in diabetic cardiac remodelling, especially during cardiac development, remains unclear. This study aims to elucidate the effect of hyperglycaemia on the p38 MAPK signalling pathway in a cardiac developmental model. Methods Pluripotent mouse embryonic stem cells (mESCs) were differentiated in vitro into cardiaclike pulsatile embryoid bodies (EBs) using the hanging drop method. Once pulsatile, EBs were further cultured for 72 hours in either baseline (25mM) or high glucose (50mM) media or with the pro-oxidant hydrogen peroxide (100μM). Changes in EB morphology and beating characteristics were observed using transmitted light microscopy. Immunocytochemistry and fluorescence microscopy imaging was used to detect changes in biomarkers. The nuclear uptake of propidium iodide (PI) was used to evaluate cell viability, whereas the 5-ethynyl-1- deoxyuridine (EdU) assay was used to determine cell proliferation. Western blot was used to analyse protein expression. Results Treatment with hydrogen peroxide stunted EB growth and decreased EB diameter, consistent with the presence of oxidative stress. High glucose increased the number of pyknotic-like nuclei and reduced the number of EdU-positive nuclei. Furthermore, hyperglycaemia elevated the expression of phosphorylated p38 MAPK, without altering total p38 MAPK expression levels. Inhibition of p38 MAPK by SB203580 in high glucose attenuated the increased number of pyknotic-like nuclei in high glucose and enhanced the number of EdUpositive nuclei compared to high glucose alone. High glucose also reduced the expression of the mitochondrial fusion regulatory protein, optic atrophy-1 (OPA1), with the inhibition of p38MAPK in high glucose attenuating this effect. Conclusion Hyperglycaemia induced pyknotic-like phenomenon, suppressed the proliferation, and reduced mitochondrial fusion protein machinery of mESC-derived cardiac-like cells. These effects were likely triggered by a mild form of oxidative stress and involved the activation of p38 MAPK. The findings provide insights into the mechanisms underlying diabetic developmental cardiac remodelling and identify p38MAPKs as a potential therapeutic target.
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    A vector based approach for high frequency prospective correction of rigid body motion in Magnetic Resonance Imaging (MRI)
    (2019) Van Niekerk, Adam Marthinus Johannes; Meintjes, Ernesta; van der Kouwe, Andre
    Magnetic Resonance Imaging (MRI) is remarkable in that it is possible to obtain image resolutions much smaller than the wavelength of the radiated signal. This is achieved through the use of specialised gradient coils that linearly manipulate the magnitude of the magnetic field within the imaging volume. The instantaneous signal received from the subject represents a periodically varying map based on the duration and magnitude (moment) of the previously applied gradient fields. Representing an object as the sum of periodic maps is difficult and as a result many unique gradient moments are required to form an image. When the subject moves the periodic maps are no longer coherent and the constructive/destructive interference becomes invalid. The artefacts are dependent on how and when motion occurred, and manifest as ghosting, ringing and blurring of the image. This thesis describes a novel approach to measuring and correcting for motion as the data are acquired. A small device was constructed that combines observations from a magnetometer (static magnetic field [z]) and an accelerometer (earth’s gravitational field [y]) with an angular rate sensor to determine its orientation with respect to the imaging coordinate frame (VectOrient). It was precise enough to track the subject’s heart beat and breathing and accurate to within one degree. A gradient field probe was then designed for position encoding. The probe measured the rate of change of the gradient magnetic fields using three mutually orthogonal pickup coils. Assuming linear gradients and using Maxwell’s equations, with negligible rates of change of curl and divergence, it was possible to accurately model the three dimensional vector fields that the gradients produce, eliminating the need for a laborious manual calibration. Sub-microsecond synchronisation was achieved by detecting radio frequency pulses in the imaging sequence with a small resonant circuit. This combined with a 2.4 GHz radio link enabled the probe to be wireless. Finally, the pickup coil observations were combined with the vector based orientation estimates and the gradient field model to achieve efficient multidimensional position, orientation and inter-gradient-delay encoding with a 880 µs pulse sequence insert. The Wireless Radio frequency triggered Acquisition Device (WRAD) tracks involuntary and deliberate subject motion, improving image quality without scanner specific calibration.
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    A wait-list controlled evaluation of the Qhubeka bicycle on an adolescent's physiology, executive function, and school performance
    (2021) Mcdonald, Reece Brian; Swart, Jeroen; Holliday, Wendy
    Learner mobility and active school travel (AST) has been proposed to improve school attendance and academic performance. In South Africa, approximately 86% of learners have been reported as walking to and from school. AST in Africa is becoming less common in urban areas, and this may be a contributing factor to the increased risk and frequency of noncommunicable diseases due to decreased physical activity. The aim of this wait-list controlled evaluation was to assess the physiological and cognitive changes of access to a bicycle versus walking on adolescents. Specifically, changes adolescent's physical activity levels and executive function in a South African low-income community. Two schools were recruited, with the evaluation school receiving bicycles and the control a school who were yet to receive bicycles. Significant differences were observed across the physiological and executive function assessments. Most notably in the executive function tests, the evaluation group showed significant time to completion decreases across all three tests (N-Back, Arrow Flanker, WCST: p< 0.001). The results from this study are significant, as they are the first to assess anthropometric, physiological and executive function in South African adolescents from low-socioeconomic regions. It is evident that there are potential improvements in working memory, inhibition and shifting due to cycling as a mode of AST or during leisuretime. Further research needs to determine the specific mechanisms associated with these improvements.
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    Adolescents’ Perspectives on the Drivers of Obesity Using a Group Model Building Approach: A South African Perspective
    (2022-02-14) Hendricks, Gaironeesa; Savona, Natalie; Aguiar, Anaely; Alaba, Olufunke; Booley, Sharmilah; Malczyk, Sonia; Nwosu, Emmanuel; Knai, Cecile; Rutter, Harry; Klepp, Knut-Inge; Harbron, Janetta
    Overweight and obesity increase the risk of a range of poor physiological and psychosocial health outcomes. Previous work with well-defined cohorts has explored the determinants of obesity and employed various methods and measures; however, less is known on the broader societal drivers, beyond individual-level influences, using a systems framework with adolescents. The aim of this study was to explore the drivers of obesity from adolescents’ perspectives using a systems approach through group model building in four South African schools. Group model building was used to generate 4 causal loop diagrams with 62 adolescents aged 16–18 years. These maps were merged into one final map, and the main themes were identified: (i) physical activity and social media use; (ii) physical activity, health-related morbidity, and socio-economic status; (iii) accessibility of unhealthy food and energy intake/body weight; (iv) psychological distress, body weight, and weight-related bullying; and (v) parental involvement and unhealthy food intake. Our study identified meaningful policy-relevant insights into the drivers of adolescent obesity, as described by the young people themselves in a South African context. This approach, both the process of construction and the final visualization, provides a basis for taking a novel approach to prevention and intervention recommendations for adolescent obesity.
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    Aetiology of fatigue during maximal and supramaximal exercise
    (2003) Nobbs, Les; Noakes, Tim; Gibson, A St Clair; Rauch, L H
    The aim of this thesis was to investigate the extent of peripheral and central components in the development of fatigue during maximal exercise. Fatigue during maximal and supramaximal excercise has traditionally been modelled from the peripheral context of an inadequate capacity to supply metabolic substrate to the contracting muscles to meet the increased energy demand.
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    African mole rats as models for regressive evolution of the eye
    (2006) Nikitina, Natalya; Kidson, Sue H
    Darkness-adapted mammals with reduced eyes can serve as valuable models for the study of regressive evolution, as well as for research into the genetic and developmental processes underlying the "degeneration" of the eye. The aim of this work was to characterize two African mole rate species (Heterocephalus glaber and Bathyergus suillus) and explore their potential use as novel models for evolutionary developmental eye research. To this end, this histological structure of the adult eye, the development of the eye and the expression of several molecular markers were investigated. The important abnormal features noted were: the abnormal shape and nuclear distribution in the lens, the extremely large ciliary body and delay in the formation of the anterior chamber compared to other ocular structures.
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    Amelioration of lipopolysaccharide-induced liver injury by aqueous rooibos (Aspalathus linearis) extract via inhibition of pro-inflammatory cytokines and oxidative stress
    (2014-10-13) Ajuwon, Olawale R; Oguntibeju, Oluwafemi O; Marnewick, Jeanine L
    Abstract Background Acute liver injury occur after intraperitoneal administration of lipopolysaccharide (LPS). Oxidative stress and release of pro-inflammatory cytokines are both implicated in the pathogenesis of LPS-induced acute liver injury. This study investigated the ameliorative effect of fermented rooibos (Aspalathus linearis) extract on LPS-induced acute liver injury. Method Major phenolic compounds in the fermented rooibos extract by HPLC-DAD, as well as the in vitro antioxidant capacity were quantified before the start of the experiment. Male Wistar rats were randomized into 4 groups (n = 10 per group) and given either water or fermented rooibos extract for 4 weeks before LPS injection. Hepatic function markers, including aminotransferases and lactate dehydrogenase, lipid peroxidation markers, antioxidant enzymes, glutathione redox status, as well as cytokine levels were monitored in the rats. Results Injection of LPS significantly increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH). Oxidative stress, evidenced by increased thiobarbituric acid reactive substances (TBARS) measured as malondialdehyde (MDA) in plasma and liver, and decreased glutathione redox status (GSH: GSSG ratio) in whole blood and liver was induced in LPS-challenged rats. Furthermore, hepatic levels of pro-inflammatory response markers TNF-α, IL-1β and IL-6 were increased significantly. Pre-feeding the fermented rooibos extract for 4 weeks decreased LPS-induced elevated levels of serum AST and LDH (significantly, p < 0.05) as well as ALT marginally. Consuming rooibos caused an attenuation of the observed increase in plasma and hepatic MDA, decrease in whole blood and liver GSH:GSSG ratio, as well as the changes noted in various antioxidant enzymes. The elevation in TNF-α and IL-6 was significantly suppressed, indicating an inhibition of the induced inflammatory response by rooibos. Conclusion Overall, our data showed that aqueous rooibos extract attenuated LPS-induced liver injury possibly by modulating oxidative stress and suppressing pro-inflammatory cytokines formation.
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    An analysis of the partial feasibility of a novel cardiac exercise rehabilitation programme for patients suffering from cardiovascular disease
    (2022) Ross, Tayla Jane; Kroff, Jacolene; Atterbury, E
    Introduction: Substantial research has shown that the inclusion of exercise in cardiac rehabilitation has a favourable effect on many outcome variables, and that exercise should be considered a vital and central component for cardiovascular disease (CVD) rehabilitation. South Africans are facing a growing epidemic of CVD, which has major implications for healthcare services and has placed increasing strain on the already grabbling South African healthcare system. Cost-effective primary and secondary prevention and management strategies are needed to slow down the growing CVD epidemic and relieve strain on health-care systems. The need exists for more evidence to demonstrate that cardiac exercise rehabilitation programmes (CRPs) can significantly reduce readmissions, mortality, comorbidities, and improve quality of life. Aims: The aims of this study were to determine the partial feasibility of a novel CRP in a South African public hospital setting by evaluating the following: 1) The recruitment potential and sample population characteristics of those considered eligible to partake in the exercise component of a novel CRP; and 2) The testretest reliability of the tools utilized for the safe monitoring of the exercise intensity during the prospective CRP. Methods: The recruitment potential and sample population characteristics of the target population were determined via retrospective analysis of a hospital admission patient database spreading over three months. The database was searched for demographic data including age, sex, height, weight, waist circumference and BMI, the admission diagnosis, patient co-morbidities and medications. The test-retest reliability of the monitoring tools was conducted on apparently healthy participants who underwent a series of monitoring measures before and after a 6-min motion test on two separate occasions. The test-retest reliability of each monitoring tool was determined using intraclass correlation coefficients (ICCs), effect size calculation and Bland-Altman plots. Results: One hundred and nine patients (52.2%) were considered ineligible for a CRP, whereas 100 individuals (47.8%) were considered eligible. Significant differences were identified between the eligible and ineligible populations were for four comorbidities and two medications. Twenty-two outcome measures were assessed for reliability, five of which were classified as having “poor” reliability, nine as “moderate”, three as “good” and five as “excellent' according to ICCs. Eighteen measures revealed excellent test-retest reliability, and the remaining 8 measures (Baseline Systolic Blood Pressure; Baseline Diastolic Blood Pressure; Baseline Oxygen Saturation; Immediately Post-Exercise Oxygen Saturation; Immediately Post-Exercise RPE; 5-Minutes Post-Exercise Systolic Blood Pressure; 5-Minutes Post-Exercise Oxygen Saturation; and 5-Minutes Post-Exercise RPE) had showed small effect sizes between 0.2-0.5, which was considered acceptable. Conclusion: The results from the analysis of the recruitment potential from a public hospital setting reveal that approximately 33 patients (100 patients/3 months) will be eligible per CRP intake, and the recruitment potential of eligible patients currently exceeds the prospective resource and staff capacity of the CRP. Further investigation is required to address and resolve the shortcoming in resources to offer the CRP to all eligible participants. The results from the test-retest reliability of the monitoring tools used within the CRP revealed that most of the equipment and measures achieved sound reliability, except for the blood pressure monitors, pulse oximeters and RPE scale. Alternative devices for monitoring blood pressure, oxygen saturation and RPE are recommended.
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    An Attempt to Improve Stance Mechanics of Trans-Tibial Amputee Gait by the Design of a Modular Ankle Joint Prosthetic
    (2018) During, Alastair B; Vicatos, George; Sivarasu, Sudesh
    Background: A-priori research shows that trans-tibial (TT) amputees display poor gait parameters when walking with low-cost ankle-foot prosthetics (here referred to as baseline AFP’s). This has drastic implications for the amputee populations in the developing world specifically, as they have limited access to advanced prosthetic technologies. Low-cost AFP’s are unable to adequately replicate natural stance mechanics, and reliance on these devices results in increased energy expenditure, osteoarthritis and lower-limb joint deterioration. Methodology: This project details the design of a novel ankle joint prosthetic (AJP) that serves as an attachment to baseline AFP’s, with the aim of facilitating better stance mechanics via the restoration of ankle joint mechanisms. The work is presented in three core sections: Part 1 explains the rationale as to why adequately replicating natural stance mechanics is an appropriate need; Part 2 presents the design of the modular low-cost AJP that utilises only simple mechanical elements; and Part 3 presents the experimental quantification of the impact the AJP has on stance mechanics of a baseline AFP (Otto Bock 1D10) in a simulation of the TT amputee walking gait cycle, via the use of three able-bodied participants and a pseudo-prosthesis. Results: The results indicate that the AJP significantly improves the stance mechanics of the baseline AFP. During forefoot rollover a stable joint moment and an increase in joint range of motion (RoM) was observed, yielding a decrease in ankle stiffness. During initial weight acceptance of early stance, an increase in joint RoM displays the restoration of controlled plantarflexion, which indicates an improved transition from heelstrike to footflat. This is a critical mechanism that facilitates stability control during weight acceptance, and the results suggest that the designed AJP is performing better in this regard than its closest functional competitor. However, equipment errors limited the ability to accurately report on ankle stiffness of this phase. Conclusions: Overall the final conclusions are that the designed AJP improves rollover shapes of the baseline AFP, eases phase transitions, and facilitates stability control and forward tibial progression. In combination with the low cost price (±50 USD), its ease of assembly and modular design, the AJP is thus a preferable option for low-income amputees in developing countries. Finally, there is significant evidence of functional and mechanical reliability, and therefore testing of the device can progress to a clinical study involving amputee participants.
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    An exploration of the molecular mechanisms underlying the effects of hyperglycaemia on the autorrhythmicity of cardiac-like stem cells
    (2023) Menzele, Amanda; Gwanyanya, Asfree
    Introduction Diabetes mellitus with uncontrolled hyperglycaemia is a major risk factor for heart rhythm disturbances. Hyperglycaemia during pregnancy is particularly concerning, as offspring of poorly controlled diabetic mothers are at an increased risk of developing life-long serious cardiovascular complications. Although structural abnormalities such as congenital heart defects and hypertrophic cardiomyopathy are by far the most common sequelae in these infants, it is becoming increasingly apparent that a vulnerability towards malignant dysrhythmias is far more prevalent than generally reported in the literature. Unfortunately, the mechanistic link between hyperglycaemia and impaired foetal cardiac electrophysiology is poorly understood. Using a cardiac developmental cellular model, this study aimed to explore the effects of hyperglycaemia on the autorrhythmicity of mouse embryonic stem cell (mESC)-derived cardiac-like cells.
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    An in vitro study of neutrophil chemotaxis
    (1976) Todd, Gail; Dowdle, E B
    When, at the beginning of 1972, my scientific attention was first drawn to the subject of cellular participation in the inflanunatory response, I was struck by the need for an understanding of the cellular and molecular mechanisms whereby blood leucocytes are attracted to an area of injury. The literature at that time contained good technical accounts of methods available for studying chemotaxis in vitro and many reports of diverse compounds of biological origin with attractant, or chemotactic, properties for motile, phagocytic cells. In general, these reports tended to substantiate the belief that chemical substances generated at an inflannnatory source attracted cells to that source in a teleologically appropriate way and they justified, by the consistent correlation observed, the relevance of in vitro procedures for studying the phenomenon. In other words, answers were available to the question "What substances attract?"; very few were available to the question, "How do they attract?".
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    An investigation into variations in the venous drainage pattern in brains of adolescents and adults
    (2020) du Toit, Francesca; Louw, Graham J
    It is well established that the brain changes dramatically in appearance during gestation and even after birth. Due to the multi-channelled origins and the number of developmental options, the adult venous system is characterised by a higher incidence of anatomical variations than the arterial system. Limited information is available on anatomical variation of the complete cerebral venous system. It is important to have an understanding of the usual drainage pattern the cerebral venous system and its anatomical variations to provide a foundation for future studies on anomalous venous structures. The extent to which fetal drainage patterns persist postnatally has yet to be established. The goal of the current study was to accurately describe the cerebral venous drainage patterns, including persistence of fetal drainage patterns in children, adolescents and adults in order to understand anatomical variations and the clinical impact during cerebrovascular interventions. For the current study 302 magnetic resonance images with contrast medium from the Groote Schuur and Red Cross Children's War Memorial Hospitals were retrospectively reviewed. The volumes of the dural venous sinuses were traced using a novel approach developed for the study. The approach included constructing 3D models of the dural venous sinuses and using the tracings for statistical and morphological analyses. No images of children met the inclusion criteria and therefore further analyses of the subset was not possible. Statistical analyses were performed to determine if there are any associations between venous sinus volume and sex, age, cerebral dominance and/or variations. Significant differences were noted for sex, dominance and variations of the cerebral venous system. The confluence of sinuses (CS) showed the most abundant number of variations. Although many studies and classifications have been made regarding the variations of these structures, there is a lack of a comprehensive classification that includes all variations. The goal of the current study was to determine the anatomical variations more comprehensively particularly at the level of the superior sagittal sinus (SSS) and confluence of sinuses. The study improved on the current literature by using contrast enhanced images as opposed to nonenhanced images or results obtained at autopsy. It is also the first study to establish a tracing protocol for venous volume to determine cerebral dominance and describe variations of the dural venous sinuses.
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    An investigation of the fluorescence emitted by arterial intimas during irradiation by a XeCl excimer laser
    (1995) Bhagwandin, Niresh; Breuer, H; Bunn, A E; Fincham, J E
    Laser angioplasty of occluded arteries has been limited by the unacceptably high rate of vessel wall perforation. To overcome this limitation, fluorescence spectroscopy of arterial wall tissue has been proposed as a technique to discriminate between normal and atherosclerotic arteries and thereby prevent arterial wall perforation during laser angioplasty.