Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The emergence and re-emergence of viral human pathogens from wildlife sources in the recent past has led to increased studies and surveillance of wildlife for potentially zoonotic agents in order to gain a better understanding of the pathogens, their sources as well as events that may lead to viral emergence. Of the >1407 known human pathogens, 13% are classified as emerging or re-emerging, and 58% as zoonotic; 37% of the (re-)emerging and 19% of the zoonotic pathogens are RNA viruses, accounting for the majority of recently emerged infectious diseases with a zoonotic origin, such as HIV, Ebola, Hendra, Nipah, Influenza and SARS. This study focusses on potentially zoonotic viruses hosted by rodents (Muridae family), shrews (order previously known as Insectivora/Soricomorpha, now reclassified as Eulipotyphla) and bats (order Chiroptera). Rodents and bats represent the largest (~40%) and second largest (~25%) mammalian orders and both occur on every continent except Antarctica. Together, the three mammalian orders investigated represent the most relevant potential sources of new zoonoses. In this study I investigated the occurrence of astroviruses, arenaviruses, coronaviruses and hantaviruses in South African small mammal species belonging to the orders mentioned above. These viruses have either been implicated in recent emerging zoonotic events or are considered to have the potential to cause cross-species transmissions resulting in a zoonotic event. In the first part of the study specimens collected from various bat, rodent and shrew species were screened for viral sequences by broadly reactive PCRs; positive samples were characterised by sequencing and sequence analysis. A separate part of the study focussed on hantavirus disease in humans: a seroprevalance survey was conducted to determine the presence of hantavirus antibodies in the local population. Additionally, acutely ill patients with potential hantavirus disease were tested in an attempt to identify possible acute infections and define clinical hantavirus disease in South Africa. Screening of rodent and shrew specimens resulted in the identification of eight novel arenavirus sequences. Seven of the sequences are related to Merino Walk virus, a recently identified South African arenavirus, and the eighth sequence represents a novel lineage of Old World arenaviruses. Screening of bat specimens resulted in the identification of highly diverse novel astrovirus and coronavirus sequences in various South African bat species, including the identification of a viral sequence closely related to the recently emerged Middle East Respiratory Syndrome coronavirus. While the study did not identify hantavirus infections in any of the acutely ill patients, it found seroprevalences similar to those observed in Europe and West Africa. The results obtained highlight the importance of small mammals in the emergence of potential zoonoses and further reinforce the importance of viral surveillance of relevant wildlife species. Further in-depth studies of naturally infected reservoir host populations are required in order to gain a better understanding of virus-host dynamics and the events that lead to virus emergence. / German Research Foundation (DFG) (project number: KR1293/9-1/13-1) / The Polio Research Foundation and the NHLS Research / Harry Crossley Foundation, the Polio Research Foundation and Stellenbosch University for granting scholarships and bursaries for PhD.

Thesis (PhD)-- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Introduction: The cardioprotective actions of the hormone melatonin against myocardial ischaemiareperfusion injury (IRI) are well-established. It has recently been shown to prevent the harmful effects of hyperphagia-induced obesity on the susceptibility of the heart to IRI as well as many of the harmful effects of obesity and insulin resistance. However, the exact mechanism whereby it exerts its beneficial action is still unknown. The aims of this study were to determine the effects of relatively short-term melatonin treatment in a rat model of diet-induced obesity on: (i) biometric and metabolic parameters, lipid peroxidation, myocardial IRI and intracellular signalling (ii) mitochondrial oxidative phosphorylation function (iii) cardiomyocyte glucose uptake and intracellular signalling. In addition, the effects of acute melatonin treatment of cardiac microvascular endothelial cells (CMEC) were determined on cell viability, nitric oxide production (NO), TNF- -induced dysfunction and intracellular signalling. Material and Methods: Male Wistar rats were randomly allocated to two groups for 20 weeks feeding with either standard rat chow or a high calorie diet. Each group was subdivided into 3 groups receiving either water throughout or melatonin (4mg/kg/day, in the drinking water) for the last 6 or 3 weeks of the experimental programme. Hearts, perfused in the working mode, were subjected to ischaemia/reperfusion and infarct size determined. Mitochondria and cardiomyocytes were isolated according to standard techniques and oxidative function and glucose uptake respectively determined. CMEC NO production and cell viability were quantified by FACS analysis of the fluorescent probes, DAF-2/DA and propidium iodide/Annexin V respectively. Intracellular signalling was evaluated using Western blot and appropriate antibodies. Results: The high-calorie diet caused significant increases in body weight gain, visceral adiposity, fasting blood glucose, serum insulin, triglycerides, HOMA-IR index and a concomitant reduction in serum adiponectin levels as well as larger myocardial infarct sizes after exposure to IRI compared to the control, indicating increased susceptibility to damage. Three as well as six weeks of melatonin administration to obese and insulin resistant rats reduced serum insulin levels and the HOMA-IR index. Myocardial infarct size was reduced in both control and diet groups. These effects were associated with increased activation of baseline myocardial STAT- 3 and the RISK pathway during reperfusion. The diet had no effect on the oxidative phosphorylation capacity of mitochondria, isolated from non-perfused hearts (baseline), but melatonin administration for 6 weeks induced a reduction in state 3 respiration rate; mitochondria isolated from diet hearts subjected to global ischaemia, exhibited an attenuated oxidative phosphorylation process which was improved by melatonin treatment. Melatonin in vitro enhanced cardiomycyte insulin stimulated glucose uptake of normal young rats but not of insulin resistant rats. In vivo melatonin treatment for 6 weeks increased basal (in diet group) and insulin stimulated glucose uptake in both control and diet groups. Melatonin (1nM) in vitro caused a significant reduction in necrosis and apoptosis of cultured CMEC, associated with a decrease in nitric oxide availability and eNOS activation and a concomitant increase in PKB/Akt, p38MAPK and AMPK activation. The harmful effects of TNF- treatment on signalling in CMEC could be prevented by co-treatment with melatonin. Conclusions: The results suggest that short-term melatonin treatment was able to significantly attenuate the diet-induced increased myocardial susceptibility to ischaemia/reperfusion damage. It may also improve cardiac glucose homeostasis and mitochondrial oxidative phosphorylation in an insulin resistant state. Melatonin in vitro protects CMEC against apoptosis and necrosis and reduces nitric oxide availability. These beneficial effects of melatonin may ultimately be due to its antioxidant capacity or receptor-mediated actions, but this remains to be established. / AFRIKAANSE OPSOMMING: Inleiding: Die vermoë van die hormoon, melatonien, om die hart teen iskemie/ herperfusiebesering (IHB) te beskerm, is welbekend. Onlangs is ook getoon dat melatonien IHB en verskeie van die nadelige effekte van vetsug en insulienweerstandigheid in hiperfagiegeïnduseerde vetsug kan voorkom. Die meganisme(s) betrokke by hierdie voordelige prosesse is egter grootliks onbekend. Die doel van hierdie studie was om die gevolge van korttermyn melatonienbehandeling in ‘n model van hiperfagiegeïnduseerde vetsug te ondersoek op (i) biometriese en metaboliese parameters, lipiedperoksidasie, miokardiale IHB en intrasellulêre seintransduksie, (ii) mitochondriale oksidatiewe fosforilasie, (iii) glukoseopname en intrasellulêre seintransduksie in kardiomiosiete en aanvullend, (iv) die invloed van akute melatonienbehandeling van kardiale mikrovaskulêre endoteelselle op sellulêre oorlewing, stikstofoksiedproduksie, TNF- - geïnduseerde disfunksie en seintransduksie. Metodiek: Manlike Wistarrotte is ewekansig in twee groep verdeel en vir 20 weke met standaard-rotkos of ‘n hoëkaloriedieet gevoer. Elke groep is in 3 subgroepe verdeel, wat deurgaans water of melatonien (4mg/kg/dag in die drinkwater) vir 3 of 6 weke voor die beëindiging van die eksperiment ontvang het. Harte is geperfuseer volgens die werkharttegniek, blootgestel aan iskemie/herperfusie en die infarktgrootte bepaal. Mitochondria en kardiomiosiete is volgens standaardtegnieke geïsoleer vir bepaling van oksidatiewe funksie en glukoseopname respektiewelik. NO produksie en sellewensvatbaarheid was gekwantifiseer deur vloeisitometriese analises (FACS) van die fluoresserende agense, DAF-2/DA en propidium jodied/Annexin V onderskeidelik. Intrasellulêre seintransduksie is evalueer met behulp van die Western kladtegniek en geskikte antiliggame. Resultate: Die hoëkaloriedieet het ‘n beduidende toename in liggaamsgewig, visserale vet, vastende bloedglukose, seruminsulienvlakke, trigliseriede, HOMA-IR-indeks en ‘n gepaardgaande verlaging in serumadiponektienvlakke tot gevolg gehad, sowel as groter miokardiale infarkte na iskemie/herperfusie. Laasgenoemde dui op ‘n groter vatbaarheid vir iskemiese beskadiging in harte van vetsugtige diere. Drie sowel as ses weke van melatonienbehandeling het die seruminsulienvlakke en HOMAindeks in vetsugtige diere beduidend verlaag, vergeleke met die kontroles. Miokardiale infarktgroottes was verminder in beide kontrole- en vetsuggroepe. Hierdie effekte het met ‘n verhoogde aktivering van basislyn STAT-3 en PKB/Akt en ERKp44/p42 tydens herperfusie gepaard gegaan. Die dieet het geen invloed op die oksidatiewe fosforilasiekapasiteit van mitochondria, geïsoleer uit harte van ongeperfuseerde harte, gehad nie (basislyn), maar melatonienbehandeling vir 6 weke het Staat 3 respirasie verlaag. Mitochondria, geïsoleer uit harte van vetsugtige rotte wat aan globale iskemie onderwerp was, het ‘n onderdrukte oksidatiewe fosforilasieproses gehad, wat egter deur melatonienbehandeling verbeter is. Melatonien in vitro het insuliengestimuleerde glukoseopname deur kardiomiosiete van jong, maar nie vetsugtige rotte nie, verhoog. In vivo melatonientoediening vir 6 weke het egter basale (in die dieetgroep) en insuliengestimuleerde glukoseopname in beide kontrole- en vetsuggroepe verhoog. Toediening van melatonien in vitro aan mikrovaskulêre endoteelselkulture het ‘n beduidende afname in nekrose, apoptose, stikstofoksied- beskikbaarheid en eNOS aktivering teweeggebring, tesame met ‘n verhoogde aktivering van PKB/Akt, p38MAPK en AMPK. Die nadelige effekte van TNF- toediening op seintransduksie in die mikrovaskulêre endoteelselle is deur melatonien voorkom. Gevogtrekkings: Die resultate toon dat melatonien ‘n merkwaardige beskermende effek op die toename in vatbaarheid vir iskemiese beskadiging in vetsugtige rotte gehad het. Dit mag ook miokardiale glukose-homeostase en mitochondriale oksidatiewe funksie in insulienweerstandigheid verbeter. Melatonien in vitro beskerm mikrovaskulêre endoteelselle teen nekrose asook apoptose en verminder die beskikbaarheid van stikstofoksied. Hierdie voordelige effekte van melatonien mag aan sy anti-oksidantvermoëns of stimulasie van die melatonienreseptor toegeskryf word, maar bewyse daarvoor ontbreek nog. / Division of Medical Physiology (Stellenbosch University), / National Research Foundation / Harry Crossley Foundation

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Ischaemic heart disease is a major contributor to global morbidity and mortality rates. Manoeuvres such as ischaemic preconditioning confer cardioprotection against ischaemia/reperfusion (I/R) injury by activating several intracellular signalling pathways. These pathways have been defined solely in terms of the kinases involved, despite the realization in recent years that protein phosphatase activity also contributes significantly to the attributes of the propagated signal. Protein phosphatase 2A (PP2A) is a heteromultimeric enzyme involved in an array of phosphatase reactions. We hypothesized that PP2A is an important participant in the myocardial response to I/R by regulating intracellular signalling. This project aimed to (i) characterize PP2A during myocardial I/R; (ii) determine the importance of its contribution to the cellular response to I/R; and (iii) investigate its role in the signalling pathways mediated by PKB/Akt, GSK-3β, ERK p42/p44 and p38 MAPK. Two models were used to characterize PP2A during I/R: (i) H9c2 cells exposed to simulated ischaemia (SI) buffer in conjunction with hypoxia (0.5% O2) for a maximum of 2 hours, followed by reoxygenation in standard growth medium for up to 30 minutes; and (ii) isolated working rat hearts exposed to a maximum of 20 minutes global ischaemia and 10 minutes reperfusion. In both models samples were collected at several time points during I/R for Western blotting analysis. PP2A-C (the catalytic subunit) accumulated in the nucleus during early ischaemia, but later redistributed to the cytosol. At the end of ischaemia there was an elevation of PP2A-C relative to PP2A-A in the unfractionated whole cell preparation concomitant with an increase in the inhibitory phosphorylation of PP2A-C. The impact of PP2A activity was evaluated by either inhibiting PP2A using okadaic acid (OA, 10 nM) or activating it by administering FTY720 (1 μM) in an isolated working rat heart model exposed to either 35 minutes of regional ischaemia (RI) with infarct size (IFS) as primary end-point, or 20 minutes global ischaemia (GI) with functional recovery as end-point. The results showed that the pre-ischaemic administration of OA or FTY720 reduced or exacerbated IFS respectively, indicating that PP2A activation during I/R favours cell death. OA and FTY720 were also employed to assess the contribution of PP2A to intracellular signalling in an isolated working rat heart exposed to I/R. Samples were collected at several timepoints and analyzed using Western Blotting. Pre-ischaemic administration of OA enhanced the phosphorylation of PKB/Akt, ERK p42/p44 and GSK-3β at the onset of reperfusion, while FTY720 given before ischaemia reduced the phosphorylation of GSK-3β, p38 MAPK and PKB/Akt at the end of ischaemia and onset of reperfusion. In summary, PP2A is part of an early nuclear-based response to ischaemia, while long-term ischaemia induces an increase in PP2A-C. A portion of this PP2A-C is stored in an inactive form, while an active portion acts as a regulator of the pro-survival signalling components PKB/Akt, GSK- 3β and ERK p42/p44 at the end of ischaemia and the onset of reperfusion. PP2A is therefore an important component of the myocardial response to I/R by regulating pro-survival signalling. / AFRIKAANSE OPSOMMING: Iskemiese hartsiekte is een van die belangrikste komponente wat bydra tot globale morbiditeit en mortaliteit. Ingrepe soos iskemiese prekondisionering aktiveer veelvoudige intrasellulêre seintransduksiepaaie om kardiobeskerming teen iskemie/herperfusie (I/H)-besering te ontlok. Die kinases betrokke in hierdie seintransduksiepaaie is reeds deeglik nagevors, terwyl die potensiële belang van die proteïenfosfatases in seintransduksie tot onlangs misken is. Ons hipotese was dat Proteïenfosfatase 2A (PP2A), wat in ‘n wye verskeidenheid fosfatase reaksies betrokke is, ‘n belangrike rolspeler in die miokardiale reaksie op I/H-besering is, deur deelname aan die regulering van intrasellulêre seintransduksie. Hierdie projek het ten doel gehad om (i) PP2A te karakteriseer tydens miokardiale I/H; (ii) die belang van PP2A in die sellulêre reaksie op I/H-besering te bepaal; en (iii) PP2A se rol in die seintransduksiepaaie, gemedieer deur PKB/Akt, GSK-3β, ERK p42/p44 en p38 MAPK, te evalueer. Twee modelle is aangewend om PP2A tydens I/H te karakteriseer: (i) H9c2-selle blootgestel aan ‘n simuleerde iskemiebuffer tesame met hipoksie (0.5% O2) vir ‘n maksimum van 2 uur gevolg deur heroksiginasie in standaardgroeimedium vir verskillende tydsperiodes tot ‘n maksimum van 30 minute; en (ii) geïsoleerde, werkende rotharte blootgestel aan ‘n maksimum van 20 minute globale iskemie en 10 minute herperfusie. In beide modelle is monsters op verskillende tye versamel vir Western-kladanalise. Tydens vroeë iskemie het PP2A-C in die kern toegeneem, waarna dit met verloop van tyd na die sitosol herversprei het. Teen die einde van iskemie was daar ‘n toename in die vlakke van PP2A-C relatief tot PP2A-A in ongefraksioneerde weefselhomogenate, tesame met ‘n toename in die inhibitoriese fosforilering van PP2A-C. Die belang van PP2A-aktiwiteit is ondersoek deur die effek te bepaal van die inhibisie of aktivering daarvan op infarktgrootte (IFS) en funksionele herstel in ‘n geïsoleerde werkende rothartmodel, blootgestel aan onderskeidelik 35 minute streeksiskemie (RI) of 20 minute globale iskemie. Preiskemiese toediening van die PP2A-inhibitor okadaïensuur (OA, 10 nM), of aktiveerder FTY720 (1 μm) het infarktgrootte respektiewelik beperk of vergroot. PP2A-aktivering tydens I/H is dus nadelig. OA en FTY720 is ook aangewend om die bydrae van PP2A tot I/H-verwante, intrasellulêre seintransduksie in die geïsoleerde, werkende rothart te bepaal. Monsters is op verskeie tydintervalle versamel en ontleed deur gebruik te maak van die Western-kladtegniek. Preiskemiese toediening van OA het die fosforilering van PKB/Akt, ERK p42/p44 en GSK-3β by die aanvang van herperfusie bevoordeel, terwyl pre-iskemiese toediening van FTY720, die fosforilering van GSK-3β, p38 MAPK en PKB/Akt aan die einde van iskemie en die begin van herperfusie verminder het. Ter opsomming: PP2A is deel van ‘n vroeë gelokaliseerde kerngebaseerde reaksie op iskemie, terwyl langdurige iskemie ‘n toename in PP2A-C relatief tot PP2A-A induseer. ‘n Deel van hierdie PP2A-C is onaktief, terwyl die res funksioneer in die regulering van die seintransduksiekomponente PKB/Akt, GSK-3β en ERK p42/p44 wat oorlewing fasiliteer met die aanvang van herperfusie. PP2A is dus ‘n belangrike komponent in die miokardiale reaksie op I/H deurdat dit tot die beheer van seintransduksiepaaie bydra.

Thesis (PhD)-- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Ventricular arrhythmias are the most important cause of sudden cardiac death (SCD) among adults living in industrialised nations. Genetic factors have substantial effects in determining population-based risk for SCD and may also account for inter-individual variability in susceptibility. Great progress has been made in identifying genes underlying various Mendelian disorders associated with inherited arrhythmia susceptibility. The most well studied familial arrhythmia syndrome is the congenital long QT syndrome (LQTS) caused by mutations in genes encoding subunits of myocardial ion channels. Not all mutation carriers have equal risk for experiencing the clinical manifestations of disease (i.e. syncope, sudden death). This observation has raised the possibility that additional genetic factors may modify the risk of LQTS manifestations. This study establishes the genetic aetiology of LQTS in South Africa and Denmark through the identification and characterisation of LQTS-causative mutations in five previously identified genes, as well as examining possible novel genetic causes of LQTS in a cohort comprising Danish and British probands. We have functionally characterised several of the mutations identified in this study and examined other cardiac phenotypes that may be explained by variants causing repolarisation disorders. / AFRIKAANSE OPSOMMING: Ventrikulêre aritmie bly die enkele belangrikste oorsaak van skielike hart dood (SCD) onder volwassenes wat in geïndustrialiseerde lande woon. Genetiese faktore het aansienlike gevolge in die bepaling van bevolking-gebaseerde risiko vir SCD en kan ook verantwoordelik wees vir die inter-individuele variasie in vatbaarheid. Groot vordering is gemaak in die identifisering van gene onderliggende verskeie Mendeliese siektes wat verband hou met geërf aritmie vatbaarheid. Die mees goed bestudeerde familie aritmie sindroom is die aangebore lang QT-sindroom (LQTS) wat veroorsaak word deur mutasies in gene kode subeenhede van miokardiale ioonkanale. Nie alle mutasie draers het 'n gelyke risiko vir die ervaring van die kliniese manifestasies van die siekte (dws sinkopee, skielike dood). Hierdie waarneming het die moontlikheid genoem dat genetiese faktore anders as die primêre siekte-verwante mutasie kan die risiko van LQTS manifestasies verander. Hierdie studie stel die genetiese oorsake van LQTS in Suid-Afrika en Denemarke deur die identifisering en karakterisering van LQTS-veroorsakende mutasies in vyf voorheen geïdentifiseer gene, asook die behandeling van moontlike nuwe genetiese oorsake van LQTS in 'n groep wat bestaan uit van die Deense en die Britse probands. Ons het funksioneel gekenmerk verskeie van die mutasies wat in hierdie studie ondersoek en ander kardiovaskulêre fenotipes wat deur variante veroorsaak repolarisasie versteurings verduidelik word. / South African National Research Foundation / Harry and Doris Crossley Foundation / Danish Strategic Research Foundation.

Dissertation (PhD)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Activation of the NO-cGMP pathway is associated with myocardial protection against ischaemia/reperfusion injury. However, high-cholesterol diets alter function of this pathway and these alterations have been implicated in both ischaemic/reperfusion injury and the development of ischaemic heart disease. Little is known about the effects of supplements such as Red Palm Oil (RPO) on the myocardial NO-cGMP-signalling pathway. RPO consists of saturated, mono-unsaturated and poly-unsaturated fatty acids and is rich in antioxidants such as β-carotene and Vitamin E (tocopherols and tocotrienols). The aims of this study were: 1) to determine whether dietary RPO-supplemention protects against ischaemia/reperfusion injury in rats fed a standard rat chow (control) and cholesterol-enriched diets and 2) if so, to investigate possible mechanisms for this protection. Male Long-Evans rats were fed a standard rat chow or a standard rat chow plus cholesterol and/or RPO-supplementation for 6 weeks. Myocardial functional recovery was measured and hearts were freeze-clamped for determination of myocardial phospholipid, cAMP/cGMP concentrations, total myocardial nitric oxide concentrations, lipid hydroperoxide production and superoxide dismutase- and nitric oxide synthase activity in isolated rat hearts subjected to 25 minutes of normothermic total global ischaemia. In addition, the degree of phosphorylation of extracellular signal-regulated kinase (ERK), p38, c-Jun N-terminal protein kinase (JNK) and protein kinase B (PKB/Akt) was investigated. Furthermore, the effect of RPO-supplementation on caspase-3 activation and poly (ADP-ribose) polymerase (PARP)-cleavage in hearts subjected to ischaemia and reperfusion was also investigated. Our data show that dietary RPO-supplementation protects the hearts of rats on a standard rat chow (control) and hypercholesterolaemic diet against ischaemia/reperfusion injury as reflected by improved aortic output recovery. Increased intracellular cardiomyocyte NO concentrations as observed in control hearts supplemented with RPO after 120 minutes hypoxia may contribute to the elevated cGMP concentration and may confer some of the cardioprotection to the ischaemic/reperfused heart. Although improved functional recovery with RPO-supplementation of a high-cholesterol diet was also associated with an increase in intracellular cardiomyocyte NO production after hypoxia compared to the non-hypoxic conditions, it could not be linked to increased NO-cGMP signalling. These data are in agreement with other studies, which showed that high-cholesterol diet impairs NO-cGMP signalling and confirms our hypothesis that elevated cGMP concentrations may not be the only mechanism of protection. We have also shown that RPOsupplementation caused increased phosphorylation of p38 and PKB, reduced phosphorylation of JNK and attenuation of PARP cleavage, which may contribute to the protection of the cell against apoptosis. Based on our results we propose that the myocardial protection offered by RPO-supplementation of rats on a normal and hypercholesterolaemic diet may be associated with either its antioxidant characteristics and/or changes in the fatty acid composition of the myocardium during ischaemia/reperfusion. Furthermore, we demonstrated for the first time that RPO-supplementation protects the isolated perfused working rat heart during reperfusion from ischaemia/reperfusion-induced injury through a MAPK-dependent pathway. / AFRIKAANSE OPSOMMING: Aktivering van die NO-cGMP sein transduksie pad word geassosieer met miokardiale beskerming teen isgemie/herperfusie skade. Hoë cholesterol diëte verander egter die funksie van die pad en hierdie veranderings speel ‘n rol in beide isgemie/herperfusie besering en die ontwikkeling van isgemiese hartsiekte. Daar is egter min inligting beskikbaar oor die uitwerking van aanvullings soos rooi palm olie (RPO) op die miokardiale NO-cGMP sein transduksie pad. RPO bevat versadigde, mono-onversadigde en poli-onversadigde vetsure en is ryk aan anti-oksidante nl. β-karotene en vitamien E (tokoferole en tokotriënole). Die doelwitte van hierdie studie was: 1) om vas te stel of ‘n RPO-aanvulling beskerming bied teen isgemie/herperfusie besering in rotte wat gevoed is met ‘n standaard rotmengsel (kontrole) en cholesterol-verrykte dieet en 2) indien wel, om moontlike meganismes van beskerming te ondersoek. Long-Evans manlike rotte is vir 6 weke gevoer met ‘n standaard rotmengsel of ‘n standaard rotmengsel plus cholesterol en/of RPO-aanvulling. Miokardiale funksionele herstel is gemeet en harte is gevriesklamp vir die bepaling van miokardiale fosfolipied, cAMP/cGMP, totale stikstofoksied, lipied hidroperoksied, superoksied dismutase en stikstofoksied sintase in geïsoleerde rotharte wat vir 25 minute onderwerp was aan normotermiese totale globale isgemie. Hiermee saam is die graad van fosforilering van ekstrasellulêre sein gereguleerde kinase (ERK), p38 mitogeen-geaktiveerde proteïen kinase (p38 MAPK), c-Jun-N-terminale proteïenkinase (JNK) en proteïen kinase B (PKB/Akt) ondersoek, asook kaspase-3 aktivering en poli (ADP-ribose) polimerase (PARP) kliewing in harte blootgestel aan isgemie en herperfusie. Ons resultate toon dat RPO-aanvulling van rotte op ‘n normale en hipercholesterolemiese dieet die hart beskerm soos getoon deur verbeterde herstel van aortiese uitset. Verhoogde intrasellulêre miokardiale NO vlakke in kontrole harte met ‘n RPO-aanvulling wat blootgestel was aan 120 minute hipoksie, mag bygedra het tot die verhoogde cGMP vlakke en beskerming van die hart tydens isgemie en herperfusie. Alhoewel verbeterde funksionele herstel met RPO-aanvulling van ‘n hoë cholesterol dieet ook geassosieer is met ‘n toename in intrasellulêre miokardiale NO produksie ná hipoksiese toestande, kon dit nie verbind word met verhoogde aktivering van die NOcGMP sein transduksie pad nie. Hierdie resultate stem ooreen met ander studies wat aangetoon het dat hoë-cholesterol diëte die NO-cGMP seinpad onderdruk. Hierdie bevinding bevestig ons hipotese dat verhoogde cGMP vlakke moontlik nie die enigste beskermingsmeganisme is nie. Ons resultate het ook gewys dat RPO-aanvulling fosforilering van p38 en PKB/Akt verhoog, fosforilering van JNK verminder en PARP kliewing onderdruk. Dit dui op beskerming van die sel teen apoptose. Ons resultate dui aan dat die miokardiale beskerming wat RPO-dieet aanvulling bied moontlik geassosieer kan word met sy anti-oksidant eienskap en/of veranderinge in die vetsuur samestelling van die miokardium tydens isgemie/herperfusie. Ons het ook vir die eerste keer bewys dat RPO-aanvulling die geïsoleerde geperfuseerde werkende rothart gedurende herperfusie beskerm teen isgemie/herperfusie besering deur die aktivering en/of deaktivering van die MAPK afhanklike pad.

Thesis (MScMedSc)--Stellenbosch University, 2012. / Bibliography / ENGLISH ABSTRACT: Background: In the era of antiretroviral therapy (ART), the risk of acquired immune deficiency syndrome (AIDS) related deaths has decreased and people living with Human Immunodeficiency Virus (HIV) now have prolonged life spans. However, an increasing trend of non-AIDS associated deaths has been reported despite adequate control of viral loads. HIV infection is established as a chronic inflammatory condition which is associated with an increased risk for thrombosis. Thus HIV infected patients are at a higher risk of developing cardiovascular disease (CVD) and other inflammatory-associated complications. Inflammation is linked with thrombosis and promotes the formation of thrombin, which plays an important role in platelet activation. Furthermore, activated platelets have been shown to play a key role during infection and the inflammatory process, particularly by mediating interactions between cells of innate immunity. Soluble markers of platelet activation have been shown to be increased in HIV-infection. However, these have not been well documented by flow cytometry. P-selectin CD62P is stored in the alpha granules of platelets and is expressed on the surface only upon platelet activation. This facilitates interaction with other blood cells and the endothelium. Activated platelets may play a role in HIV-induced atherosclerosis through the expression and release of mediators that induce endothelial activation and support the adhesion of leukocytes to the inflamed vessel wall. Fibrinogen is a precursor of the blood coagulatory protein fibrin and the degradation of fibrin to D-dimer is a measure of the formation and the subsequent dissolution of blood clots. In HIV infected patients, chronic inflammation induces the up-regulated expression of tissue factor (TF) on monocytes which triggers the activation of the clotting cascade and increases the level of D-dimers. Methods: This pilot study consisted of ART naïve patients and all platelet flow analyses were carried out on whole blood. In this study, a total of 57 adult South Africans were recruited from a clinic in the Western Cape. These included 32 HIV positive patients and 25 HIV negative individuals. The levels of platelet activation and platelet function were investigated using a novel platelet cytometry assay. The method was optimized to ensure minimal platelet activation: no centrifugation or red blood cell (RBC) lysis steps were performed. The platelet-specific markers CD41a and CD42b were used to ensure gating on platelets only. CD62P expression was used to evaluate platelet activation and these levels were correlated with Fibrinogen, hsCRP, Ddimer, CD4 counts and viral load. Furthermore, platelet function was evaluated by investigating the response of platelets to endogenous agonists which included adenosine diphosphate(ADP) and arachidonic acid (AA) at varying concentrations. Results:This study demonstrated higher baseline levels of CD62P expression in treatment naïve HIV positive patients as compared to uninfected controls (mean %CD62P 71.74 ± 2.18 vs control 54.52 ± 2.42; p=<0.0001). In addition it was shown that %CD62P expression correlated directly with platelet counts (r=0.374, p=0.042). Platelet counts showed an inverse correlation with viral loads (give values) Fibrinogen levels correlated with the absolute WCC (r=0.659, p=0.0021); absolute neutrophil count (r=0.619, p=0.0105); absolute monocyte count (0.562, p=0.0235) and hsCRP (r=0.688 p=0.0011). In addition, fibrinogen showed a strong negative correlation with CD4 counts (r=-0.594, p=0.0014) and therefore, may be a valuable marker of both disease progression and risk of thrombosis in treatment naïve HIV positive patients. HsCRP levels correlated with the absolute neutrophil counts (r=0.392, p=0.0005). The HIV Group showed an overall hyper-response to ADP at a concentration 0.025 μM as compared to uninfected controls (62.34 ± 9.7 vs control 36.90 ± 5.7, p=0.0433). Conclusions: In this study we describe a novel Flow Cytometry technique that may be used to evaluate the levels of platelet activation and platelet function in HIV infected patients. In addition we report a cost-effective panel in the form of fibrinogen, WCC and platelets that may be valuable in predicting the progression of HIV infection to AIDS or other inflammatory- associated complications in treatment naïve HIV infected patients. Platelet counts showed an inverse correlation with viral loads and a direct correlation with the level of activated platelets. These findings taken together suggest the potential prognostic value of platelet activation and platelet counts in the context of asymptomatic HIV infected patients. Our findings suggest WCC and Fibrinogen may be used to evaluate the inflammatory profile of individual HIV infected patients. This may have a direct impact on HIV patient management prior to initiation of antiretroviral therapy and valuable in monitoring responses to treatment. Further, we present a novel flow cytometry based platelet functional assay and suggest the use of ADP at a concentration of 0.025 μM to evaluate platelet function optimally in HIV infected patients. The utilization of the novel Flow Cytometry technique as described in this study would add significant value in the assessment of thrombotic risk and disease progression in HIV infected patients and may additionally prove to be of value in other chronic inflammatory conditions. / AFRIKAANSE OPSOMMING: Voorkennis: In die era van antiretrovirale terapie (ART), het die risiko van vigs-verwante sterftes verminder en mense wat nou met volle naam (MIV) leef, het ‘n verlengde lewensduur. Nogtans, word 'n toenemende neiging van nie-vigs geassosieer sterftes berig wat hoofsaaklik toegeskryf word aan trombotiese toestande. MIV-infeksie word as 'n chroniese inflammatoriese toestand beskou met ʼn verhoogde trombose risiko geassosieer word. Dus, MIV-besmette pasiënte het 'n hoër risiko om kardiovaskulêre siekte (CVD) te ontwikkel ongeag of hulle ARV naïef is of op behandeling is nie. Inflammasie word geassosieer met trombose en bevorder die vorming van trombien, wat 'n belangrike rol in plaatjie aktivering speel. Verder, word daar bewys dat geaktiveerde bloedplaatjies 'n belangrike rol speel tydens infeksie en die inflammatoriese proses.Hulle bemiddel interaksies tussen die selle van ingebore immuniteit. Daar word bewys dat oplosbare merkers van plaatjie aktivering verhoog is in MIV-infeksie, maar die bewyse is nie so goed gedokumenteer deur vloeisitometrie nie. P-selectin (CD62P) word gestoor in die alfa korrels van plaatjies en word uitgedruk op die oppervlak slegs wanneer plaatjies geaktivering word; daardeur fasilitering dit die interaksie met ander bloedselle en die endoteel. Geaktiveerde plaatjies kan ook 'n rol in MIV-geïnduseerde aterosklerose speel deur middel van die uitdrukking en vrylating van bemiddelaars wat endoteel aktivering induseer asook die adhesie van leukosiete aan die ontsteekte vat wand ondersteun.. Fibrinogeen, 'n voorloper van die bloed koagulatories proteïen fibrin en die degradasie van fibrin na D-dimeer is' n maatstaf van die vorming en die daaropvolgende ontbinding van bloedklonte. Kroniese inflammasie in MIVbesmette pasiënte, induseer die op-gereguleerde uitdrukking van weefsel faktor (TF) op monosiete wat die aktivering van die stolling kaskade inisieer en die D-dimere vlakke verhoog. Metodes: Hierdie loodsstudie bestaan uit ART naïewe pasiënte en al die plaatjie vloei ontleding was op vol bloed uitgevoer. In hierdie studie, 'n totaal van 57 volwasse Suid-Afrikaners was van' n kliniek in die Wes-Kaap gewerf. Dit sluit 32 MIV-positiewe pasiënte en 25 MIV negatiewe individue in. Die vlakke van plaatjie aktivering en plaatjie funksie was ge ondersoek deur middel van 'n nuwe plaatjie sitometrie toets. Die metode was geoptimaliseer om minimale plaatjie aktivering te verseker: dus geen sentrifugering of volle naam (RBS) liseer stappe was gebruik nie. Die plaatjie-spesifieke merkers, CD41a en CD42b was gebruik om te verseker dat slegs bloedplaatjes gekies word. Die uitdrukking van CD62P was gebruik vir die evaluering van plaatjie aktivering en hierdie vlakke was gekorreleer met fibrinogeen, hsCRP, D-dimeer, CD4- tellings en virale lading. Verder, was plaatjie funksie geëvalueer deur die reaksie van plaatjies aan endogene agoniste wat ADP en AA by wisselende konsentrasies insluit te ondersoek. Results: Hierdie studie het getoon hoër basislyn vlakke van CD62P uitdrukking in behandeling naïewe MIV-positiewe pasiënte in vergelyking met onbesmette beheermaatreëls (beteken% CD62P 71,74 ± 2,18 vs beheer 54,52 ± 2,42, p <0.0001). Daar is ook getoon dat% CD62P uitdrukking direk gekorreleer met plaatjie tellings (r = 0,374, p = 0,042). Plaatjie tellings het 'n omgekeerde korrelasie met virale ladings (gee waardes) fibrinogeen vlakke korreleer met die absolute WCC (r = 0,659, p = 0,0021), absolute neutrofiel telling (r = 0,619, p = 0,0105); absolute monosiet telling (0,562, p = 0,0235) en hsCRP (r = 0,688 p = 0,0011). Daarbenewens, fibrinogeen het 'n sterk negatiewe korrelasie met 'n CD4-tellings (r = -0,594, p = 0,0014) en daarom kan 'n waardevolle merker van beide die siekte en die risiko van trombose in behandeling naïewe MIV-positiewe pasiënte. HsCRP vlakke gekorreleer met die absolute neutrofiel tellings (r = 0,392, p = 0,0005). Die MIV-groep het 'n algehele hiper-reaksie op die ADP by 'n konsentrasie 0,025 μM in vergelyking met onbesmette beheermaatreëls (62,34 ± 9,7 vs beheer 36,90 ± 5.7, p = 0,0433). Gevolgtrekkings: In hierdie studie beskryf ons 'n roman vloeisitometrie tegniek wat gebruik kan word om die vlakke van Plaatjie aktivering en plaatjie funksie in die MIV-besmette pasiënte te evalueer. Verder het ons 'n verslag van 'n koste-effektiewe paneel in die vorm van fibrinogeen, WCC en plaatjies wat waardevol kan wees in die voorspelling van die vordering van MIVinfeksie tot VIGS of ander inflammatoriese-verwante komplikasies in die behandeling naïewe MIV-besmette pasiënte. Plaatjie tellings het 'n omgekeerde korrelasie met die virale laste en 'n direkte verband met die vlak van geaktiveerde bloedplaatjies. Hierdie bevindinge saam, dui op die moontlike prognostiese waarde van Plaatjie aktivering en die plaatjie tel in die konteks van die asimptomatiese MIV-geïnfekteerde pasiënte. Ons bevindinge dui daarop WCC en fibrinogeen kan gebruik word om die inflammatoriese profiel van individuele MIV-geïnfekteerde pasiënte te evalueer. Dit kan 'n direkte impak op MIV pasiënt vooraf aan die inisiasie van antiretrovirale terapie en waardevolle in die monitering van die reaksie op behandeling. Verder bied ons 'n roman vloeisitometrie gebaseer plaatjie funksionele toets en dui op die gebruik van die ADP teen 'n konsentrasie van 0,025 μM plaatjie funksie optimaal te evalueer in MIVgeïnfekteerde pasiënte. Die benutting van die roman vloeisitometrie tegniek soos beskryf in hierdie studie sal 'n beduidende waarde toevoeg in die beoordeling van die die trombotiese risiko en die siekte in MIV-geïnfekteerde pasiënte en kan addisioneel bewys van waarde te wees in 'n ander chroniese inflammatoriese toestande. / National Reserach Foundation

Stellenbosch University. Faculty of Medicine and Health Sciences. Interdisciplinary Health Sciences. Family Medicine and Primary Care. / Thesis (MFamMed) -- Stellenbosch University, 2010. / Bibliography / ENGLISH ABSTRACT: Introduction: This thesis summarises the findings of a medical audit on the management of Cryptococcal Meningitis (CM). The study population of HIV positive adults (N = twenty five) were admitted during November 2009 – June 2010 to five hospitals of the Cape Winelands (East) District, Western Cape, South Africa. In the context of the HIV pandemic, CM has become the most common cause of community-acquired meningitis, and has poor outcomes if left untreated. The South African HIV Clinician Society has published treatment guidelines in 2007. These guidelines have been used by the audit team to compile a list of measurable criteria (with set targets) to evaluate the structure, process and outcome of CM management. A pilot audit (2008) at the regional hospital has demonstrated that certain target standards were not met. Aims and Objectives: The aim was to improve the quality of the clinical care of HIV-patients diagnosed with CM in the Cape Winelands (East) district. The objectives included the review of the audit criteria and target standards, demonstrating improvement in quality of CM care at the Level 1 and 2 hospitals, identifying new interventions based on the findings and providing recommendations to the health facilities. Methods In 2009, the researcher formed a new audit team, reviewed the audit criteria and held teaching interventions based on the national treatment guidelines. An intervention, based on the findings of the pilot audit, aimed at improving the clinical team’s adherence to the treatment guidelines. Results The audit identified the following areas that did not meet the target standards: the availability of Amphotericin B (Ampho B) and spinal manometers; the use of manometry in all initial lumbar punctures (LPs); completing fourteen days of the required Ampho B treatment; renal monitoring in patients on Ampho B; commencement of antiretroviral treatment (ART) by week four; and, the two-month survival figures post-diagnosis. The re-audit at the Level 2 hospital highlighted the need for improved medical record keeping to aid the audit process. Arrangement of inpatient ART counselling happened more consistently at the Level 1 hospitals. Adherence to the ART target and measures to prevent Ampho B related morbidity is comparable to that of the Level 2 hospital. The audit has also provided insight to the researcher and audit team on the practical challenges of conducting a prospective data collection technique across different care settings. Recommendations Level 1 hospitals should continue to manage CM patients. The availability of spinal manometers and closer adherence to renal monitoring require attention. Formal feedback to the audit team and clinical teams is planned. A multimodal interdisciplinary Quality Improvement approach (such as an integrated care pathway) is recommended and a future re-audit is encouraged to assess improved adherence to the CM management guidelines. The buy-in of stakeholders (management, health care workers and patients), the ongoing support of an audit team and a committed Quality Improvement environment will allow the medical audit process to become ingrained in the South African public healthcare setting. / AFRIKAANSE OPSOMMING: Inleiding Hierdie tesis bied ‘n opsomming van die sleutelbevindinge van ‘n mediese oudit van Cryptokokkale Menigitis (CM) sorg. Die studie groep van MIV-positiewe volwassenes (N = vyf-en-twintig) het binne-pasiënt behandeling ontvang gedurende November 2009 tot Junie 2010 in vyf hospitale van die Kaapse Wynland (Oos) distrik. In die konteks van die MIV pandemie het CM die mees algemene oorsaak van gemeenskapsverworwe meningitis geword, en het swak uitkomste indien onbehandeld. Die Suid-Afrikaanse HIV Clinici Vereniging het in 2007 behandelingsriglyne gepubliseer. Hierdie riglyne het die oudit span gebruik om ‘n lys van meetbare kriteria (met teiken standaarde) saam te stel om die struktuur, proses en uitkoms fasette van CM sorg te evalueer. ‘n Proef oudit (2008) by die streekshospitaal het getoon dat sekere teiken standaarde nie behaal was nie. Doelstelling Die doelstelling was om die kwaliteit van kliniese sorg van MIV-pasiënte met CM (in die Kaapse Wynland (Oos) distrik) te verbeter. Die doelstelling sluit in die hersiening van die oudit kriteria, die bevesting van verbetering in kwaliteit CM sorg by vlak 1 en 2 hospitale, identifisering van nuwe ingreep-moontlikhede gebaseer op die bevindinge en die verskaffing van toepaslike aanbevelings aan die gesondheidsorg fasiliteite. Metodes Die navorser het in 2009 ‘n nuwe oudit span gevorm, die oudit kriteria hersien en opleidingsingrepe geskoei op die nasionale riglyne gefasiliteer. Opleidingsingrepe, gebaseer op bevindinge van die proef oudit, het ten doel gehad dat die kliniese span die nasionale riglyne nakom. Resultate Die oudit het die volgende areas uitgelig waar daar nie aan die teikenstandaarde voldoen was nie: the beskikbaarheid van Amphotericin B (Ampho B) en spinale manometers; die gebruik van manometrie in alle aanvanklike lumbaal punksies (LPs); voltooi van die veertien dae Ampho B behandelingsteiken; nierfunksie monitoring van pasiënte op Ampho B; aanvang van anti-retovirale behandeling teen week vier; en, die twee maande oorlewing post-diagnose syfers. Die opvolg oudit by die vlak 2 hospitaal bevestig die belang van verbeterde kliniese notas om die oudit proses te vergemaklik. Die reël van binne-pasiënt ART berading gebeur meer bestendig in Vlak 1 hospitale. Bereiking van die ART teiken en maatreëls om Ampho B verwante morbiditeit te voorkom, is vergelykbaar met die bevindinge by die vlak 2 hospitaal. Die oudit het die navorser en die oudit span ingelig rakende die praktiese uitdagings om ‘n prospektiewe data insamelingsmetode te poog in verskillende kliniese kontekste. Aanbevelings Vlak 1 hospitale kan steeds CM pasiënte versorg. Die beskikbaarheid van spinale manometers en deeglike nierfunksie monitering sal die behaling van teiken standaarde vergemaklik. Formele terugvoer aan die oudit span en kliniese span word beoog. ‘n Multimodale interdissiplinêre Kwaliteitsverbeterings benadering (soos ‘n geïntegreerde sorgplan) word aanbeveel en ‘n toekomstige oudit word aangemoedig om verbetering in toepassing van die CM riglyne te evalueer. Dit is belangrik om die sleutelspelers (bestuur, gesondheidswerkers en pasiënte) te betrek. Verder word voortgesette ondersteuning van die oudit span en ‘n toegewyde omgewing van kwaliteitsverbetering aanbeveel. Sodoende sal die oudit proses in Suid-Afrikaanse publieke sorg geintegreer word.

Thesis (MMed (Pathology. Forensic Medicine))--University of Stellenbosch, 2010. / Bibliography / ENGLISH ABSTRACT: Background - The workload of the forensic pathologist and Forensic Pathology Services staff is increased by the referral of potentially unnecessary natural cases to the Forensic Pathology Services. The primary aims of the medico-legal autopsy are limited to establishing a cause of death in presumed unnatural cases, and to exclude criminality or negligence. Objective – To determine the final outcomes of forensic post-mortem examinations in “sudden and unexpected” adult deaths over a 5 year period. Methods - An observational, retrospective, descriptive study was conducted. ”Sudden and unexpected” adult deaths referred to Tygerberg Forensic Pathology Services between 1 January 2001 and 31 December 2005 were reviewed. Data was collected from the autopsy reports, contemporaneous notes and hospital records. Findings – A total of 816 adult cases of sudden and unexpected death were referred to Tygerberg Forensic Pathology Services over the 5 year period studied. Complete autopsies had been performed in 74% (601/816) of cases. The presumed manner of death was natural in 79 % of cases, and an increase in the number of natural cases autopsied per year was noted over the 5-year study period. Diseases of the cardiovascular, respiratory and central nervous systems were responsible for the majority of natural deaths. Infectious diseases were responsible for most deaths in the youngest age group studied (18-29 years). Acute alcohol poisoning was responsible for the deaths of 35 (6%) cases, with an average blood alcohol concentration of 0.38g/100mL in these cases. Eight deaths were drug-/substance related. Waiting times for blood alcohol and toxicology results increased over the 5-year study period. No cause of death was found in 10.6% of cases. Conclusions -The questionnaire and interviewing structure could possibly be improved in order to obtain better pre-autopsy information and to reduce the number of “unnecessary” medicolegal autopsies, thereby reducing the burden of cost on the Forensic Pathology Services. / AFRIKAANSE OPSOMMING: Agtergrond – Die werkslading van die forensiese patoloog en ander personeel van die Forensiese Patologie Dienste word vermeerder deur die verwysing van moontlik onnodige natuurlike gevalle na die Forensiese Patologie Dienste. Die primêre doelwitte van die medies-geregtelike nadoodse ondersoek is beperk tot die bepaling van ‘n oorsaak van dood in vermoedelik onnatuurlike gevalle, en om nalatigheid of kriminele aksies uit te skakel. Doelwit – Om die finale uitkomste van medies-geregtelike nadoodse ondersoeke in “skielike en onverwagte” volwasse sterftes oor ‘n 5-jaar tydperk te bepaal. Metodes – ‘n Observasionele, retrospektiewe, beskrywende studie is uitgevoer. “Skielike en onverwagte” volwasse sterftes wat verwys is na Tygerberg Forensiese Patologie Dienste vanaf 1 Januarie 2001 tot 31 Desember 2005 is hersien. Inligting is versamel vanaf die nadoodse ondersoekverslae, kontemporêre notas en hospitaalnotas. Bevindinge – Agthonderd en sestien volwasse gevalle van skielike en onverwagte sterftes is oor die 5-jaar periode verwys na Tygerberg Forensiese Patologie Dienste. Volledige lykskouings is uitgevoer in 74% (601/816) van die gevalle. Die vermoedelike wyse van die sterfte was natuurlik in 79.04% en ‘n toename in die aantal natuurlike gevalle wat lykskouings ondergaan het, is waargeneem oor die 5-jaar studie tydperk. Siektes van die kardiovaskulêre, respiratoriese en sentrale senuweestelsel was verantwoordelik vir die meerderheid natuurlike sterftes. Infektiewe toestande was verantwoordelik vir die meeste sterftes in die jongste ouderdomsgroep (18-29 jaar) wat bestudeer is. Akute alkoholvergiftiging was verantwoordelik vir die sterftes van 35 (6%) gevalle, met ‘n gemiddelde bloed-alkohol-konsentrasie van 0.38g/100mL in hierdie gevalle. Agt sterftes was dwelm-/middelverwant. Die wagtyd vir bloed-alkohol en toksikologie resultate het vermeerder oof die 5-jaar studie tydperk. Die oorsaak van dood was nie gevind in 10.6% van gevalle. Afleidings – Die vraelys en onderhoud-struktuur kan moontlik verbeter word om sodoende beter inligting te verkry voor die uitvoering van ‘n lykskouing, en om die aantal “onnodige” medies-geregtelike nadoodse ondersoeke te verminder, en sodoende die kostedruk te verminder op die Forensiese Patologie Dienste.

Thesis (MScMedSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Hepatitis B virus (HBV) immunisation protocols in much of Africa are based on data from the pre-human immunodeficiency virus (pre-HIV) era that indicated that HBV transmission occurs predominantly horizontally between siblings and play-mates rather than vertically from mother to child. The immunosuppression associated with HIV infection however may release HBV from immune control resulting in higher HBV viral loads, which may increase the risk of perinatal mother to child transmission of HBV. The aim of this study was to determine the prevalence and characteristics of chronic HBV infection in HIV-infected pregnant women compared to HIV-uninfected pregnant women in the Western Cape province of South Africa. Ethical approval was obtained to conduct a retrospective, matched case-control, unlinked anonymous study using residual plasma samples from the 9355 pregnant women included in the Western Cape's 2008 National HIV and Syphilis Antenatal Survey. Samples were tested for HBsAg on the AxSYM (Abbott, Chicago, IL) and confirmed by neutralization. Confirmed HBsAg-positive samples were tested for HBeAg, anti-HBe and anti-HD (Diasorin, Saluggia, Italy) and had HBV viral load and genotyping done. In addition, HBsAg-negative samples were tested for anti-HBc. Samples from 1549 HIV-infected pregnant women were included and matched to the same number of samples from age- and race-matched HIV-uninfected women. Median age of 26 years, parity and education were similar in the two groups. The prevalence of HBsAg was 3.4% for the HIV-infected group and 2.9% for the HIV-uninfected group. HBV DNA loads of greater than 104 IU/ml were detected in 32.1% of HBsAg-positive, HIV/HBV co-infected women, and in 14.3% HBsAg positive, HBV mono-infected women. Among the HIV-infected group 18.9% of HBsAg-positive were HBeAg positive, with a median viral load of 7.93 log10 IU/ml; whilst 15.5% HIV-uninfected women were positive for HBeAg with a median viral load of 6.07 log10 IU/ml. Genotype A was seen in 92.6% of the isolates while 7.4% of the isolates were genotype D. Serum total anti-HBc antibodies that are a marker of past infection were detected in 42.2% of HIV-infected and in 24.1% of HIV-uninfected women that were negative for HBsAg. No positive sample for anti-HD was seen among all HBsAg-positive samples. This data indicates that there is increased exposure to HBV in HIV-infected pregnant women than in HIV-uninfected women and that a greater proportion of HIV-infected pregnant women compared to HBV mono-infected pregnant women may be at increased risk of transmitting HBV to their infants. Further studies are needed to determine the rate of vertical transmission of HBV in the HIV era. / AFRIKAANSE OPSOMMING: Hepatitis B virus (HBV) immunisasie protokolle vir meeste dele van Afrika is gebaseer op data versamel in die era voor MIV. Die data dui aan dat HBV oordrag hoofsaaklik deur horisontale transmissie tussen broers, susters en speelmaats eerder as vertikale transmissie van moeder na kind plaasvind. Die onderdrukking van die immuunstelsel as gevolg van MIV infeksie kan egter lei tot 'n verhoogde risiko van perinatale HBV oordrag van moeder na kind. Die doel van hierdie studie was om die voorkoms en karakter van chroniese HBV infeksie in MIV-positiewe swanger vroue te vergelyk met die van MIV-negatiewe swanger vroue. Etiese goedkeuring is verkry om 'n retrospektiewe, deursnee-, ongekoppelde anonieme studie uit te voer wat gebruik maak van oorblywende plasma monsters van 9355 swanger vroue wat ingesluit is in die Wes-Kaap 2008 Nasionale MIV en Sifilis Voorgeboortelike Opname. Die monsters was getoets vir HBsAg antiliggame (AxSYM, Abbott, Chicago, IL) en bevestig deur neutralisasie toetse. Positiewe monsters was getoets vir HBeAg en anti-HBe (Diasorin, Saluggia, Italië). HBV viruslading en genotipering was ook op HBsAg positiewe monsters gedoen. Die HBsAg negatiewe monsters was getoets vir die teenwoordigheid van anti-HBc. Monsters van 1549 MIV-positiewe swanger vroue was ingesluit in die studie. Dieselfde aantal monsters van MIV-negatiewe vroue, met ooreenstemende ouderdom en etnisiteit, was ingesluit as kontroles. Die gemiddelde ouderdom van albei groepe was 26 jaar. Pariteit en opvoeding was dieselfde in albei groepe. Die voorkomssyfer van HbsAg was 3.4% in die MIV-positiewe groep en 2.8% in die MIV-negatiewe groep. HBV DNS ladings van meer as 104 IU/ml was waargeneem in 32.1% van die MIV-mede-geinfekteerde vroue en in 14.3% van die MIV-negatiewe groep. In die MIV-positiewe groep was 18.9% vroue HBeAg positief, met 'n gemiddelde virale lading van 7.93 log10 IU/ml, terwyl 15.5% MIV-negatiewe vroue positief was vir HBeAg met 'n gemiddelde virale lading van 6.07 log10 IU/ml. In ons studie was 92.6% van die monsters genotipe A en 7.4% genotipe D. Toatale anti-HBc antiliggame, 'n merker van vorige infeksie, was gevind in 42.2% van MIV-mede-geïnfekteerde vroue en 24.1% van MIV-negatiewe vroue wat negatief was vir HBsAg antiliggame. Data van ons studie dui op 'n verhoogde risiko vir vertikale HBV transmissie van MIV-positiewe moeders na hul babas. Verdere studies word benodig om vas te stel of vertikale transmissie van HBV van MIV-positiewe vroue na hul babas plaasvind. / Wellcome Trust / Poliomyelitis Research Foundation

Thesis (MSCMedSc)--Stellenbosch University, 2012. / Includes bibliography / ENGLISH ABSTRACT: Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in the world. The disease spectrum of NAFLD extends from steatosis (types 1,2) to non-alcoholic steatohepatitis (NASH) with inflammation (types 3,4). The aims of the study were 1) to analytically validate high-throughput real time polymerase chain reaction (RT-PCR) assays for three selected single nucleotide polymorphisms (SNPs), FTO rs9939609 (intron 1 T>A), TNF-α rs1800629 (-308 G>A) and PPARγ rs1801282 (Pro12Ala, 34 C>G), and 2) to perform genotype-phenotype association studies in relation to biochemical abnormalities, disease severity and age of onset. A total of 119 patients with fatty liver identified on ultrasound, including 88 histologically confirmed NAFLD patients, and 166 control individuals were genotyped for the three selected SNPs. RT-PCR validated against direct sequencing as the gold standard was used for detection of genetic variation. All three SNPs were in Hardy Weinberg equilibrium in the study population, except for a deviation in genotype distribution detected for PPARγ rs1801282 in the NAFLD patient subgroup (p<0.001). After adjustment for age and gender, the risk-associated FTO rs9939609 A-allele was detected at a significantly higher frequency in the Caucasian compared with Coloured patients (p=0.005). The opposite was detected for the risk-associated TNF-α rs1800629 A-allele, which occurred at a significantly higher frequency in the Coloured compared with Caucasian NAFLD patients (p=0.034). The onset of fatty liver disease symptoms was on average 5 years younger in the presence of each risk-associated TNF-α rs1800629 A-allele (p=0.028). When considered in the context of an inferred genotype risk score ranging from 0-6, disease onset occurred on average 3 years earlier (p=0.008) in the presence of each risk-associated FTO A-allele, TNF-α A-allele or PPARγ C-allele. After adjustment for age, gender and race, no differences in genotype distribution or allele frequencies were observed between histologically confirmed NAFLD (types 1,2) and NASH (types 3,4) patients, while the minor allele frequency for the TNF-α rs1800629 was significantly higher in the total NAFLD (types 1-4) (p=0.047) as well as NASH subgroup (NAFLD types 3,4) (p=0.030) compared with obese patients without a histologically confirmed NAFLD diagnosis. A significant correlation was furthermore observed between the number of TNF-α rs1800629 A-alleles and increasing CRP levels (p=0.029), with a favourable reduced effect in the presence of low- to moderate alcohol intake. The average waist circumference of physically active NAFLD patients was 12% lower than in physically inactive patients (p=0.004). In view of the results presented in this study, the inclusion of the selected SNPs, and in particular the pro-inflammatory TNF-α rs1800629 polymorphism, may be considered as part of a comprehensive cardiovascular risk evaluation of NAFLD patients. Ultimately, early detection of patients with fatty liver disease symptoms and effective intervention based on the underlying disease mechanism may prevent progression from NAFLD to NASH, shown to be an independent risk factor for cardiovascular diseases. / AFRIKAANSE OPSOMMING: Nie-alkoholiese lewervervetting (NALV) is die mees algemene kroniese lewersiekte in die wêreld. Die siektespektrum van NALV strek van steatose (vervette lewer tipes 1,2) tot steatohepatitis met inflammasie (NASH tipes 3,4). Die doel van die studie was 1) om analities die hoë omset polimerase kettingreaksie (RT-PKR) metode te valideer vir die geselekteerde enkel nukleotied polimorfismes (ENPs) FTO rs9939609 (intron 1 T>A), TNF-α rs1800629 (-308 G>A) en PPARγ rs1801282 (Pro12Ala, 34 C>G), en 2) om genotipe-fenotipe assosiasie studies uit te voer ten opsigte van relevante biochemiese abnormaliteite, graad van die siekte en aanvangsouderdom. ’n Totaal van 119 pasiënte met vervette lewers is geïdentifiseer met behulp van ultraklank, insluited 88 histologies-bevestigde NALV pasiënte, en 166 kontrole individue. Hierdie pasiënte is gegenotipeer vir die 3 geselekteerde ENP’s. RT-PKR gevalideer met direkte DNA volgorde bepaling as die goue standaard, is gebruik vir opsporing van genetiese variasie. Al die ENP’s was in Hardy Weinberg ekwilibrium in die studie populasie, behalwe vir ’n afwyking in genotipe verspreiding waargeneem vir PPARγ in die NALV subgroep (p<0.001). Nadat aanpassings gemaak is vir ouderdom en geslag, is die risiko-geassosieerde FTO rs9939609 A-alleel waargeneem teen ’n betekenisvol hoër frekwensie in die Kaukasiese pasiënte in vergelyking met Kleurling pasiënte (p=0.005). Die teenoorgestelde is waargeneem vir die risiko-geassosieerde TNF-α rs1800629 A-alleel wat voorgekom het teen ’n betekenisvol hoër frekwensie in die Kleurling NALV pasiënte, in vergelyking met Kaukasiese NALV pasiënte (p=0.034). Die aanvang van NALV was gemiddeld 5 jaar vroeër in die teenwoordigheid van elke risiko-geassosieerde TNF-α rs1800629 A-alleel (p=0.028). Met inagneming van ’n genotipe risiko telling tussen 0–6, het aanvang van siekte gemiddeld 3 jaar vroeër voorgekom (p=0.008) in die teenwoordigheid van elke toenemende risiko-geassosieerde FTO A-alleel, TNF-α A-alleel en PPARγ C-alleel. Nadat aanpassings gemaak is vir ouderdom, geslag en ras, is geen verskille waargeneem in genotipe verspreiding of alleel frekwensies tussen histologies bevestigde NALV (tipes 1,2) en NASH (tipes 3,4) pasiënte nie, terwyl die minor alleel telling vir die TNF-α rs1800629 betekenisvol hoër was in die totale NALV (tipes 1–4) (p=0.047) asook die NASH subgroep (NALV tipes 3,4) (p=0.03) in vergelyking met vetsugtige pasiënte sonder ’n histologies bevestigde diagnose. ‘n Statisties beteknisvolle korrelasie is verder waargeneem tussen die aantal TNF-α rs1800629 A-allele en toenemende CRP vlakke (p=0.029), met n gunstige verlaagde effek in die teenwoordigheid van lae alcohol gebruik. Die gemiddelde middellyf-omtrek van fisies aktiewe NALV pasiënte was 12% minder as fisies onaktiewe pasiente (p=0.004). Na aanleiding van die resultate van hierdie studie behoort insluiting van geselekteerde ENP’s, en in besonder die pro-inflammatoriese TNF-α rs1800629 polimorfisme, as deel van ’n omvattende kardiovaskulere risiko evaluasie oorweeg te word. Aan die einde van die dag mag vroeë identifikasie van NALV pasiente en effektieve intervensie gebasseer op die onderliggende siekte meganisme, vordering tot NASH verhoed wat getoon is om ’n onafhanklike risiko faktor vir kardiovaskulêre siekte te wees. / Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology