Photocopy of typescript. / Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

The disease caused by the protozoan Perkinsus marinus has been a major source of mortality in the eastern oyster, Crassostrea virginica. Variations in susceptibility to P. marinus infection among eastern oysters collected from the Chesapeake Bay and Gulf of Mexico, as well as between eastern and Pacific (Crassostrea gigas) oysters were determined. Since oyster host defense may play a role in determining susceptibility to pathogen infection, cellular and humoral defense activities of the oyster and their interactions with P. marinus were investigated. Procedures also had to be established to isolate, purify, and propagate in vitro, P. marinus. Eastern oysters from all sites were found to be highly susceptible to the pathogen. Cellular and humoral activities were significantly affected by heavy intensity of P. marinus infection. Prevalence and intensity of P. marinus infection were lower in Pacific oysters than in eastern oysters. Pacific oysters may offer a less favorable environment for the development of P. marinus compared to eastern oysters for at least two possible reasons: the elevated cellular and humoral activities may degrade the parasite more effectively, and lower plasma protein levels may limit parasite growth. Incubation of merozoites with hemocytes of eastern and Pacific oysters in vitro suggested that limited intracellular killing of P. marinus occurred but that killing was not mediated by oxygen metabolites. Perkinsus marinus was successfully propagated in vitro in a culture medium containing most of the known constituents of cell-free oyster hemolymph. Cultures of the parasite were initiated from heart fragments of infected oysters. The cultured protozoan was similar in morphology to P. marinus, enlarged in fluid thioglycollate medium, reacted with polyclonal antibodies raised against hypnospores and was infective. Continuous cultures of P. marinus could also be initiated from hypnospores. Two types of division, progressive cleavage and successive bipartition of the mother cell protoplast, were observed.

Epidermolysis Bullosa simplex (EBS) is a rare genetic disorder that is typically inherited in an autosomal dominant fashion and affects approximately 1 out of 20 000 individuals. This disease is caused by mutations in either the KRT14, KRT5 or PLEC genes. These genes code for proteins involved in the formation of the cytoskeleton in basal keratinocytes, which form the basal layer of the epidermis. The cytoskeleton provides structural support to the basal keratinocytes and mutations in these genes cause cytoskeletal malformations, making these cells more susceptible to physical stress. This results in the cells undergoing lysis under trivial mechanical stress and causing the epidermis to detach from the dermis, the layer immediately below the epidermis. This leads to the primary symptom of EBS: the formation of blisters. The goal of this project is to recreate EBS in zebrafish using transgenesis and to create stable mutant transgenic line. In the future, high throughput drug screening will be done on mutant zebrafish embryos to find potential drug candidates that can alleviate the symptoms of EBS. To accomplish this, missense and deletion mutations in zebrafish krt5 cDNA using site-directed mutagenesis were performed. It was previously shown that mice models for this disease die shortly after birth and thus no stable mutant lines were able to be created. To ensure embryo survival and avoid a similar fate, mutant krt5 cDNA was expressed in non-essential tissue, such as the embryonic fin fold using a fin epithelial-specific enhancer named epi. These constructs were injected into one-cell stage zebrafish embryos, which were raised and screened for integration of the construct in their germ cells. While results from injected embryos were promising, mutant transgenic zebrafish did not demonstrate any blistering. In an attempt to induce blistering, mutant zebrafish embryos were placed under various environmental stressors known to worsen the symptoms of EBS. This was not successful. Expression of mutant keratin 5 in the basal epidermis of the entire embryo using the 2.3kb upstream region of the zebrafish krt5 gene to drive expression also did not yield any results. More investigations are needed to determine if it will be possible to use the zebrafish to model EBS.

Thesis (M Med.(Community Health))--University of Limpopo, 2009. / The threat posed by infectious diseases is progressively growing on a global scale. With 2010 rapidly approaching, when South Africa will host the Soccer World Cup, there will be a massive influx of foreigners into the country. The purpose of the study was evaluate to the status of Gauteng tertiary academic hospitals with respect to outbreak response and, with the help of existing local and international policies and research, to develop a generic model that can be used by hospitals in developing outbreak response policies and standard operating procedures. Methods A descriptive cross-sectional survey using a semi-structured questionnaire was utilized to evaluate the preparedness of tertiary health care facilities in South Africa. The target population consisted of Clinical Directors, Senior Clinical Executives/ Medical Superintendents, Infection Control Nurses and / or Quality Assurance Managers and Infection Control Nurses. These categories of health professionals were targeted as they are normally delegated responsibility for outbreak response activities. Results Twelve tertiary academic hospitals were included in the survey and nine responded to the survey questionnaire giving a 75% response rate. Other significant findings were: • 71% of the responding hospitals had clear terms of reference for their response team. v • 43% of the responding hospitals had a functional preparedness and response strategy / plan for priority diseases. • The most frequent point of entry in the tertiary academic hospitals is the casualty / emergency unit, followed by the trauma and OPD areas • There are very few ‘protective environment wards’ and ‘airborne infection isolation rooms’ in Gauteng Province. • Only 15% of responding hospitals have infection control compatible ventilation and only 42% could manage a patient that requires quarantine in the casualty/ emergency unit area. Most hospitals did not have the capacity to quarantine large number of patients. The study has also illustrated that there is no model easily available, suitable for the South African context, that can be used by hospital management in facility specific planning for infectious disease outbreaks. Conclusions It can be concluded from the findings of this study that academic hospitals in Gauteng, as well as in other areas of South Africa, are not adequately prepared for the management of an infectious disease outbreak.

Thesis (M Med (Anatomical Pathology))--University of Limpopo, 2010. / Background Esophageal squamous cell carcinoma (SCC) remains a disease of poor prognosis. Early diagnosis is compromised by the delayed onset of symptoms. By the time of surgical intervention metastases and organ infiltration have already occurred this reduces the prognosis significantly and the 5-year survival rate of operative advanced esophageal SCC remains poor. In order to select an appropriate therapeutic regime and guard against both over- and under treatment, reproducible prognostic markers are needed at the time of diagnosis. The study evaluates the phenotypic expression of E-cadherin and β- catenin in SCC of the esophagus. Methods: The expression patterns of both β-catenin and E-cadherin was determined using immunohistochemistry technique in patients with esophageal SCC with the application of the Broders and Brynes grading systems in assessing clinical outcome. Forty four cases were randomly selected, one case was esophagectomy, and 43 were endoscopic biopsies with one case of Broders Grade I, 37 Grade II and 6 Grade III and 9 cases had pattern 2 and 35 had pattern 3 with Brynes Grade. Results: The reduced expression of E-cadherin and β-catenin was 45.5% and 47.7% respectively. No significant level was observed with E-cadherin (P= 0.20) and for β-catenin (P= 0.18) but the low protein level of both biomarkers was associated with tumor cell differentiation with Broders classification. The reduced expression of E-cadherin on invasive tumor front was 27% and 57% for reduced expression of β-catenin. The level of significance was found to be (P=1.00) for E-cadherin expression and (P=0.02) for β-catenin. E-cadherin and β-catenin showed reduced expression on invading tumor front and β-catenin was associated with tumor cell invasiveness. Conclusion: The expression of E-cadherin and β-catenin with regard to Broders classification showed no significance on tumor cell differentiation and these expressions do not play a role in guiding nor predict the behavior or progression of the tumor. However, the assessment β-catenin on the tumor invasive front (Brynes) shows a high correlated with tumor behavior as it is involved in regulation E-cadherin function.

Thesis (MPH)--University of Limpopo, 2011. / Introduction: Diabetes, also known as diabetes mellitus characterized by hyperglycemia is a global health problem. The World Health Organization (WHO) reports an estimated 177 million diabetics worldwide and this number is expected to double by the year 2030 mainly because of the unhealthy life styles of not doing physical exercises and eating unhealthy food. The resultant obesity is putting people at risk of developing diabetes and micro vascular complications like diabetic retinopathy that can affect a person’s eyesight. Aims and Objectives: The aim and objectives of this study were to determine the socio-economic characteristics and the level of awareness regarding the eye care services offered by the diabetic clinic at Dr George Mukhari Hospital as well as to identify the referral patterns and possible factors that may influence diabetic patients to utilize these offered services. Study methodology: Data was collected from adult diabetic patients attending the diabetic clinic at Dr George Mukhari Hospital by making use of an anonymous researcher assisted structured questionnaire. The questionnaire had sections covering the socio demographic and epidemiological information of the respondent; awareness about diabetic complications with emphasis on routine eye care; referral patterns of health professionals to the eye specialist and other barriers that the respondents experienced in attending the available eye care services. Results: Data was collected from a total of 175 respondents. The majority of the respondents were African (98%) females (75%) and older than 56 years of age (82%). Basically all the respondents (98%) did not have a medical aid and 50.3% of them were unemployed and had to make use of public transport to visit the clinic. Ninety six percent of the respondents were aware of the fact that diabetes can cause eye complications and that a routine eye test is important to prevent blindness. In this group of participants there was a referral rate of 95% which proved to be very successful because only 18% of the respondents were in need of an eye operation while the rests were treated for minor problems and then discharged. Conclusions: Based on the findings of this study all indications are that the referral patterns for diabetic patients from the diabetic clinic at the Dr George Mukhari hospital for eye testing is effective. All efforts should be made to ensure that diabetic patients go for a yearly routine eye test.

Thesis (M. Med.(Family Medicine))--University of Limpopo (Medunsa Campus), 2010. / Background: The control of STIs remains a priority for the WHO. Health – seeking and sexual behaviors are important elements in the control of sexually transmitted infections (STIs). Aim: To assess health seeking behavior in relation to STIs amongst community members of Nkomazi East area of Mpumalanga who use Tonga hospital’s feeder clinics and comprehensive health centers. Study Design: This was a quantitative research carried out as a non-experimental, descriptive cross-sectional survey employing the use of questionnaires for data collection. Questionnaires covering social, demographic, and healthcare-seeking and sexual behaviour information were administered to 332 patients attending primary care clinics in Nkomazi East area of Mpumalanga. Results: Majority of the participants were single, literate, unemployed blacks aged between 16 – 23 years (43.7%). Participants displayed an exceptionally high STI knowledge with urethral discharge, painful micturition, vaginal discharge and lower abdominal pain the most recognised STI symptoms. All the participants (100%) sought help on perceiving that they have an STI. Preferred source of help is the public health sector with traditional healers also finding some relevance. While compliance to treatment is largely satisfactory, ongoing unsafe sexual practices with active STI seem to be common place. Conclusion: Participants displayed a high knowledge of STI symptoms and signs. Public health facilities were the preferred source of health. Health seeking seemed to be influenced by multiple factors. Financial consideration was not much of a factor while seeking help compared to accessibility to health facility and stigma or shame. Belief system, influence by family members, friends and partners were also important factors influencing health seeking behaviour

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