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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Application of a New Approach Methodology (NAM)-based Strategy for Genotoxicity Assessment of Data-poor Compounds

Fortin, Anne-Marie 06 December 2022 (has links)
The conventional battery for genotoxicity testing is not well-suited to assessing the large number of chemicals needing evaluation. Traditional in vitro tests lack throughput capacity, provide little mechanistic information, and have poor specificity in predicting in vivo genotoxicity. The Health Canada GeneTox21 research program is developing a multi-endpoint platform for modernized in vitro genotoxicity assessment. The GeneTox21 assays include the TGx-DDI transcriptomic biomarker (i.e., 64-gene expression signature to identify DNA damage-inducing (DDI) substances), the MicroFlow® assay (i.e., a flow cytometry-based micronucleus (MN) test), and the MultiFlow® assay (i.e., a multiplexed flow cytometry-based reporter assay that yields mechanism-of-action (MoA) information). As part of GeneTox21 development, the objective of this study was to investigate the utility of the TGx-DDI transcriptomic biomarker, multiplexed with the MicroFlow® and MultiFlow® assays, as an integrated testing strategy for screening data-poor substances prioritized by Health Canada’s New Substances Assessment and Control Bureau. Human lymphoblastoid TK6 cells were exposed to 3 control and 10 data-poor substances, using a 6-point concentration range. Cells were exposed for 4 hours with or without exogenous metabolic activation. Gene expression profiling was conducted using the targeted TempO-SeqTM assay, and the TGx-DDI classifier was applied to the dataset. Classifications were compared with those based on the MicroFlow® and MultiFlow® assays. Benchmark Concentration (BMC) modeling was used for potency ranking. The results of the integrated hazard calls indicate that five data-poor compounds are genotoxic in vitro, causing DNA damage via a clastogenic MoA, and one is positive via a pan-genotoxic MoA. Two compounds are likely irrelevant positives in the MN test; two are considered possibly genotoxic causing DNA damage via an ambiguous MoA. From quantitative analyses of concentration-response data, we observed nearly identical potency rankings for each assay with two main potency groups being observed. This ranking was maintained when all endpoint BMCs were converted into a single score using the Toxicological Prioritization (ToxPi) approach. Overall, this study contributes to the establishment of a modernized approach for effective genotoxicity assessment and chemical prioritization for further regulatory scrutiny. We conclude that integration of the TGx-DDI biomarker with other GeneTox21 assays is an effective NAM-based strategy for genotoxicity assessment of data-poor compounds.
142

The effects of atrial repolarization on exercise-induced ST-segment depression in apparently healthy females

Brown, Rhonda K. 11 July 2009 (has links)
The relationship between the PQ-segment slope on ST-segment depression during vigorous exercise was examined in 26 apparently healthy females between 18 and 26 years of age. Each subject performed 2 submaximal cycle ergometer exercise tolerance tests (trial A and trial B) on nonconsecutive days wherein the following variables, as delta scores, were measured; P-wave amplitude (microvolts), PQ-segment slope (uV!sec), and J-point at 0 and 60 msec (uV). Each variable was measured by both visual and computer averaging. The degree of reproducibility within and between trials differed for the visual and computer averaged measures. Generally higher reproducibility was found with computer averaging particularly within trial B (r =0.63-0.89, p<O.OI). Trial b served as a basis for assessment of PQ-segment slope effect on ST segment response. Computer analysis of frequency distribution for responses revealed a greater frequency of downsloping PQ-segment with clinically significant ST-segment depression (>50 uV) at both 0 and 60 msec after the J-point in lead II. However, there was a greater percentage (91%) of flat PQ-segment slopes with clinically significant ST-segment depression at J-point 0 msec in lead V5. These findings suggest possible influence of lead selection on the measurements of the PQ-segment slope and ST-segment. Implication of clinical application would be to use lead VS for diagnosing CHD and by measuring ST-segment depression at J-point 60 msec. However when screening exercise ECG tests in apparently healthy women use J-point at 0 msec. / Master of Science
143

Knowledge, awarness and practices regarding tuberculosis among gold miners in Tanzania

Mtaita, Ghuhen Reuben 02 1900 (has links)
The overall aim of this study was to investigate the knowledge, awareness and practices regarding TB at a selected gold mine in Tanzania in order to enhance the paucity of knowledge in this area of public health. The mining population is considered to be at high risk of tuberculosis infection and illness. However, there is little data available on the knowledge, awareness and practices in the mining population in Tanzania. A quantitative, descriptive study, using the Health Belief Model as the conceptual framework, was conducted among 100 workers in order to give a detailed description of the knowledge and awareness of tuberculosis. The study confirms the role of the media, particularly radio broadcasting, health workers, teachers, and the community in promoting information and education on TB. Fever as a symptom was a problem. The study area is a malaria endemic area where fever is the commonest presentation hence every fever is regarded as malaria. This complicated picking up and identifying other causes of fever. Despite feeling compassion for and wanting to help TB sufferers, most avoided them, which emphasised people’s general fear of TB. This indicated the general isolation and stigmatisation of TB sufferers. The findings highlighted the need for on-going education about TB and its treatment, especially early diagnosis and adherence to treatment. / Health Studies / M.A. (Public Health)
144

Health and HIV risk assessment of men who have sex with men (MSM) in the Johannesburg inner city

Lalla-Edward, Samanta Tresha 06 1900 (has links)
By gathering information from a volunteer sample of men who sleep with men (MSM) in the Johannesburg inner city, the study aimed to discover those decisions and behaviour that influence their health decision-making and health-seeking behaviour, particularly as far as HIV and their sexual health was concerned. Eleven in-depth interviews were conducted by three interviewers using a semistructured interview guide which asked questions on demographics, health-seeking behaviour, sexual orientations and behaviour, knowledge of HIV/AIDS and community support. During analysis, collected data was classified into the themes of access to health care, personal and general MSM HIV risk perceptions, sexual behaviour, alcohol and unprotected sex, prostitution, religion and stigma, violence and discrimination. This study was the first qualitative study researching MSM in the Johannesburg inner city and provides useful baseline information for further qualitative MSM studies in the geographical area and for the development of MSM aligned interventions. / Sociology / M.A. Sociology
145

Sense of coherence, affective wellbeing and burnout in a higher education institution call centre

Harry, Nisha 06 1900 (has links)
The objective of this study was to: (1) assess the overall wellness climate profile of a sample of higher education call centre employees for national benchmarking purposes; (2) explore the relationship between the participants‟ sense of coherence, affective wellbeing and burnout; and (3) determine how the participants differ regarding these variables in terms of socio-demographic contextual factors such as gender, race, age, and marital status. The South African Employee Health and Wellness Survey was used as a measuring instrument. Compared to the national norm, the results indicated a risky wellness climate reflecting a burnout propensity, lower morale (affective wellbeing) and lower resilience (sense of coherence). Significant relations existed between the participants‟ sense of coherence, affective wellbeing and burnout levels. Significant differences regarding these variables were also detected between males and females and the various marital status groups regarding the participants‟ sense of coherence, affective wellbeing and burnout. The findings of this study contributed new knowledge that may be used to inform employee wellness programmes within a higher education call centre environment. The study concluded with recommendations for future research and practice. / Industrial and Organisational Psychology / M. Comm. (Industrial and Organisational Psychology)
146

Sense of coherence, affective wellbeing and burnout in a higher education institution call centre

Nisha, Harry 06 1900 (has links)
The objective of this study was to: (1) assess the overall wellness climate profile of a sample of higher education call centre employees for national benchmarking purposes; (2) explore the relationship between the participants‟ sense of coherence, affective wellbeing and burnout; and (3) determine how the participants differ regarding these variables in terms of socio-demographic contextual factors such as gender, race, age, and marital status. The South African Employee Health and Wellness Survey was used as a measuring instrument. Compared to the national norm, the results indicated a risky wellness climate reflecting a burnout propensity, lower morale (affective wellbeing) and lower resilience (sense of coherence). Significant relations existed between the participants‟ sense of coherence, affective wellbeing and burnout levels. Significant differences regarding these variables were also detected between males and females and the various marital status groups regarding the participants‟ sense of coherence, affective wellbeing and burnout. The findings of this study contributed new knowledge that may be used to inform employee wellness programmes within a higher education call centre environment. The study concluded with recommendations for future research and practice. / Industrial and Organisational Psychology / M. Comm. (Industrial and Organisational Psychology)
147

An investigation into the prevalence and risk factors of occupational musculoskeletal injuries in firefighters in the Durban Metropolitan Fire Department

Albert, Dhimunthree January 2009 (has links)
Dissertation submitted in compliance with the requirements for the Masters Degree in Chiropractic at the Durban University of Technology, 2009 / Occupational injuries sustained by Emergency Rescue Care workers have been well documented. However, despite their high rates of injury, the literature regarding the risk factors for work-related musculoskeletal injuries (WRMSIs) in the fire service has not been well-established, especially in South Africa. Objectives: To determine the prevalence and risk factors for musculoskeletal injuries in the Durban Metropolitan Fire Department and to evaluate the relationship between selected risk factors and the prevalence of musculoskeletal injuries. Methods: This was a descriptive study from a large urban Fire Department employing 350 active firefighters. Using a cross sectional study design, a retrospective analysis investigated the musculoskeletal injury prevalence from 2006-2008 by means of a questionnaire. Individuals reported on demographics, injury location, injury etiology, injury nature, extent of treatment rendered and time lost from work. Additionally, data was obtained regarding smoking, occupational stress, fitness, protective gear and injury prevention advice given by the Durban Metropolitan Fire Department. A 41% response rate was achieved. Results: The point prevalence of WRMSIs was 33.6% and the period prevalence was 81.1% of the sample. Low back injuries (47.9%) and strain injuries (40.8%) were the most common, followed by knee (22.5%), shoulder (19.7%) and ankle injuries (19%). The most common causes included lifting heavy objects, working in awkward postures and running. Weight, ethnic group, stress, lack of nutritional advice and alcohol consumption were all significantly associated with the prevalence of injuries. Ex-smoking was significant in the prevalence of low back injuries, stress was significant in the prevalence of knee injuries and alcohol consumption was associated with the prevalence of shoulder injuries. Conclusion: WRMSIs are of great concern in the fire service as their prevalence is substantial. Evaluation and implementation of further preventative measures and advice based on the results of this study can be effective in reducing WRMSIs.
148

Accuracy of risk prediction tools for acute coronary syndrome : a systematic review

Van Zyl, Johet Engela 04 1900 (has links)
Thesis (MCur)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Background: Coronary artery disease is a form of cardiovascular disease (CVD) which manifests itself in three ways: angina pectoris, acute coronary syndrome and cardiac death. Thirty-three people die daily of a myocardial infarction (cardiac death) and 7.5 million deaths annually are caused by CVD (51% from strokes and 45% from coronary artery disease) worldwide. Globally, the CVD death rate is a mere 4% compared to South Africa which has a 42% death rate. It is predicted that by the year 2030 there will be 25 million deaths annually from CVD, mainly in the form of strokes and heart disease. The WHO compared the death rates of high-income countries to those of low- and middle-income countries, like South Africa, and the results show that CVD deaths are declining in high-income countries but rapidly increasing in low- and middle-income countries. Although there are several risk prediction tools in use worldwide, to predict ischemic risk, South Africa does not use any of these tools. Current practice in South Africa to diagnose acute coronary syndrome is the use of a physical examination, ECG changes and positive serum cardiac maker levels. Internationally the same practice is used to diagnose acute coronary syndrome but risk assessment tools are used additionally to this practise because of limitations of the ECG and serum cardiac markers when it comes to NSTE-ACS. Objective: The aim of this study was to systematically appraise evidence on the accuracy of acute coronary syndrome risk prediction tools in adults. Methods: An extensive literature search of studies published in English was undertaken. Electronic databases searched were Cochrane Library, MEDLINE, Embase and CINAHL. Other sources were also searched, and cross-sectional studies, cohort studies and randomised controlled trials were reviewed. All articles were screened for methodological quality by two reviewers independently with the QUADAS-2 tool which is a standardised instrument. Data was extracted using an adapted Cochrane data extraction tool. Data was entered in Review Manager 5.2 software for analysis. Sensitivity and specificity was calculated for each risk score and an SROC curve was created. This curve was used to evaluate and compare the prediction accuracy of each test. Results: A total of five studies met the inclusion criteria of this review. Two HEART studies and three GRACE studies were included. In all, 9 092 patients participated in the selected studies. Estimates of sensitivity for the HEART risks score (two studies, 3268 participants) were 0,51 (95% CI 0,46 to 0,56) and 0,68 (95% CI 0,60 to 0,75); specificity for the HEART risks score was 0,90 (95% CI 0,88 to 0,91) and 0,92 (95% CI 0,90 to 0,94). Estimates of sensitivity for the GRACE risk score (three studies, 5824 participants) were 0,03 (95% CI0,01 to 0,05); 0,20 (95% CI 0,14 to 0,29) and 0,79 (95% CI 0,58 to 0,93). The specificity was 1,00 (95% CI 0,99 to 1,00); 0,97 (95% CI 0,95 to 0,98) and 0,78 (95% CI 0,73 to 0,82). On the SROC curve analysis, there was a trend for the GRACE risk score to perform better than the HEART risk score in predicting acute coronary syndrome in adults. Conclusion: Both risk scores showed that they had value in accurately predicting the presence of acute coronary syndrome in adults. The GRACE showed a positive trend towards better prediction ability than the HEART risk score. / AFRIKAANSE OPSOMMING: Agtergrond: Koronêre bloedvatsiekte is ‘n vorm van kardiovaskulêre siekte. Koronêre hartsiekte manifesteer in drie maniere: angina pectoris, akute koronêre sindroom en hartdood. Drie-en-dertig mense sterf daagliks aan ‘n miokardiale infarksie (hartdood). Daar is 7,5 miljoen sterftes jaarliks as gevolg van kardiovaskulêre siektes (51% deur beroertes en 45% as gevolg van koronêre hartsiektes) wêreldwyd. Globaal is die sterfte syfer as gevolg van koronêre vaskulêre siekte net 4% in vergelyking met Suid Afrika, wat ‘n 42% sterfte syfer het. Dit word voorspel dat teen die jaar 2030 daar 25 miljoen sterfgevalle jaarliks sal wees, meestal toegeskryf aan kardiovaskulêre siektes. Die hoof oorsaak van sterfgevalle sal toegeskryf word aan beroertes en hart siektes. Die WHO het die sterf gevalle van hoeinkoms lande vergelyk met die van lae- en middel-inkoms lande, soos Suid Afrika, en die resultate het bewys dat sterf gevalle as gevolg van kardiovaskulêre siekte is besig om te daal in hoe-inkoms lande maar dit is besig om skerp te styg in lae- en middel-inkoms lande. Daar is verskeie risiko-voorspelling instrumente wat wêreldwyd gebruik word om isgemiese risiko te voorspel, maar Suid Afrika gebruik geen van die risiko-voorspelling instrumente nie. Huidiglik word akute koronêre sindroom gediagnoseer met die gebruik van n fisiese ondersoek, EKG verandering en positiewe serum kardiale merkers. Internationaal word die selfde gebruik maar risiko-voorspelling instrumente word aditioneel by gebruik omdat daar limitasies is met EKG en serum kardiale merkers as dit by NSTE-ACS kom. Doelwit: Die doel van hierdie sisematiese literatuuroorsig was om stelselmatig die bewyse te evalueer oor die akkuraatheid van akute koronêre sindroom risiko-voorspelling instrumente vir volwassenes. Metodes: 'n Uitgebreide literatuursoektog van studies wat in Engels gepubliseer is was onderneem. Cochrane biblioteek, MEDLINE, Embase en CINAHL databases was deursoek. Ander bronne is ook deursoek. Die tiepe studies ingesluit was deurnsee-studies, kohortstudies en verewekansigde gekontroleerde studies. Alle artikels is onafhanklik vir die metodologiese kwaliteit gekeur deur twee beoordeelaars met die gebruik van die QUADAS-2 instrument, ‘n gestandaardiseerde instrument. ‘n Aangepaste Cochrane data instrument is gebruik om data te onttrek. Data is opgeneem in Review Manager 5.2 sagteware vir ontleding. Sensitiwiteit en spesifisiteit is bereken vir elke risiko instrument en ‘n SROC kurwe is geskep. Die SROC kurwe is gebruik om die akkuraatheid van voorspelling van elke instrument te evalueer en te toets. Resultate: Twee HEART studies en drie GRACE studies is ingesluit. In total was daar 9 092 patiente wat deelgeneeem het in die gekose studies. Skattings van sensitiwiteit vir die HEART risiko instrument (twee studies, 3268 deelnemers) was 0,51 (95% CI 0,47 to 0,56) en 0,68 (95% CI 0,60 to 0,75) spesifisiteit vir die HEART risiko instrument was 0,89 (95% CI 0,88 to 0,91) en 0,92 (95% CI 0,90 to 0,94). Skattings van sensitiwiteit vir die GRACE risiko instrument (drie studies, 5824 deelnemers) was 0,28 (95% CI 0,13 to 0,53); 0,20 (95% CI 0,14 to 0,29) en 0,79 (95% CI 0,58 to 0,93). Die spesifisiteit vir die GRACE risiko instrument was 0,97 (95% CI 0,95 to 0,99); 0,97 (95% CI 0,95 to 0,98) en 0,78 (95% CI 0,73 to 0,82). Met die SROC kurwe ontleding was daar ‘n tendens vir die GRACE risiko instrument om beter te vaar as die HEART risiko instrument in die voorspelling van akute koronêre sindroom in volwassenes. Gevolgtrekking: Altwee risiko instrumente toon aan dat albei instrumente van waarde is. Albei het die vermoë om die teenwoordigheid van akute koronêre sindroom in volwassenes te voorspel. Die GRACE toon ‘n positiewe tendens teenoor beter voorspelling vermoë as die HEART risiko instrument.
149

The prevalence of coronary risk factors among children, ages 11 to 13, in selected Western Cape schools

De Klerk, Danelle Ria 12 1900 (has links)
Thesis (MScSportSc)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Numerous studies have shown that coronary artery disease (CAD) has its origin in childhood. Several risk factors that increase a person's risk for the development of CAD are prevalent amongst children. South African statistics concerning the prevalence of these risk factors are limited. Research has shown that early intervention to eliminate risk factors can decrease the risk for the development of CAD. The purpose of this study was to determine the prevalence of certain coronary risk factors amongst children aged 11 to 13 years in certain Western Cape schools. Certain selected factors were tested. These included obesity, lack of physical activity, hypertension, low physical fitness (V02max), a family history associated with an increased risk, exposure to cigarette smoke, prevalence of diabetes mellitus and an unhealthy diet. The sample consisted out of 288 children and was made up by 154 boys and 134 girls. Certain anthropometrical measurements (stature, weight, skinfoids, waist and hip circumferences) were taken. Activity levels, family history, exposure to cigarette smoke, prevalence of diabetes mellitus and diet, were measured by means of questionnaires. Physical fitness (V02max) was tested with a three-minute step-test. A sphygmomanometer was used to measure blood pressure. Depending on the circumference of the child's arm, a paediatric or adult size cuff was used. The results of the study showed that 22.01% of the boys and 59.7% of the girls had a percentage body fat so high that it was considered a coronary risk factor. Physical fitness levels were considered risk factors in 2.6% of the boys and 9% of the girls. A very high percentage of the children tested had a family history associated with an increased risk for the development of CAD (73.38% of the boys and 78.36% of the girls). Systolic hypertension was prevalent among 22.01% of the boys and 23.13% of the girls. Diastolic hypertension was only prevalent among 5.19% of the boys and 5.97% of the girls. Low activity levels were considered a risk factor in 31.17% of the boys and 39.55% of the girls. Out of all the subjects, 32.47% of the boys and 37.31% of the girls were exposed to cigarette smoke on a daily basis. The results of this study shows that certain coronary risk factors are quite common amongst children. Prevention programmes that focuses on elimination of coronary risk factors, such as hypertension, inactivity and obesity, is essential for the prevention of subsequent coronary artery disease in adults. / AFRIKAANSE OPSOMMING: Verskeie studies het al bewys dat koronêre hartvatsiekte (KHS) reeds sy ontstaan het in kinders van baie jong ouderdomme. Verskeie risikofaktore wat tot die latere ontstaan van KHS lei kom ook onder jong kinders voor. Statistiek ten opsigte van die voorkoms van hierdie risikofaktore onder kinders in Suid-Afrika is egter baie beperk. Verskeie navorsing toon dat vroeë intervensie kan lei tot "n verlaging in risiko vir die ontwikkeling van KHS op "n latere stadium. Die doel van die studie was om die voorkoms van sekere koronêre risikofaktore in kinders in Suid-Afrika te ondersoek. Sekere risikofaktore is ondersoek, dit het ingesluit, obesiteit, lae fisieke aktiwitietsvlakke, hipertensie, lae fisieke fiksheid (V02maks), 'n familie geskiedenis wat geassosieer word met "n verhoogte risiko, blootstelling aan sigaret rook, die voorkoms van diabetes mellitus en "n swak dieet. Die steekproef het bestaan uit 288 kinders waarvan 134 meisies en 154 seuns was. Verskeie antropometriese meetings (lengte, massa, velvoue, middel- en heup omtrekmates) is geneem. Aktiwiteitsvlakke, familiegeskiedenis, blootstelling aan sigarette rook, voorkoms van diabetes mellitus en dieet is deur middel van vraelyste vasgestel. Fisieke fiksheid (V02maks) is deur middel van "n drie-minuut-opstaptoets vasgestel. Bloeddruk is met "n sfigmomanometer gemeet. Afhangend van die omtrek van die kind se arm is "n pediatries- of volwasse-grootte drukband gebruik. Persentasie liggaamsvet was by 22.01% van die seuns en 59.7% van die meisies so hoog dat dit as "n risikofaktor beskou kan word. Fisieke fiksheidsvlakke kan by 2.6% van die seuns en 9% van die meisies as "n risikofaktor beskou word. "n Baie hoë persentasie van die kinders het "n familiegeskiedenis gehad wat geassosieer word met "n verhoogde risiko vir die ontwikkeling van KHS (73.38% van die seuns en 78.36% van die meisies). Sistoliese hipertensie het onder 22.01% van die seuns en 23.13% van die meisies voorgekom. Diastoliese hipertensie het baie minder voorgekom as sistoliese hipertensie (5.19% van die seuns en 5.97% van die meisies). Lae aktiwiteitsvlakke het onder 31.17% van die seuns en 39.55% van die meisies voorgekom. 'n Redelike hoë persentasie van die kinders word daagliks aan sigaretrook van hulouers of oppassers blootgestel (32.47% van die seuns en 37.31% van die meisies.) Die resultate van die studie dui aan dat daar 'n redelike hoë voorkoms van sekere koronêre risikofaktore onder kinders is. Ondersoek moet ingestel word na moontlike, goed gestruktureerde intervensieprogramme.
150

Cardiovascular risk factors of Anglos and Mexican-American Hispanics in Pima County, Arizona

Dodson, Mary Ann Jokerst, 1939- January 1988 (has links)
A comparison study of cardiovascular risk factors between Anglos and Mexican-American Hispanics, by gender and age, was conducted with 1343 subjects in Pima County, Arizona. Data was collected through public health screenings at a variety of sites (39) throughout the community. A self-administered questionnaire and measurements of height, weight, blood pressure, total blood cholesterol and blood glucose provided the data. Risk factors (total blood cholesterol, hypertension, smoking, genetic tendency, diabetes, obesity and lack of exercise) were analyzed individually and in combination by age, gender and ethnicity. Some of the significant findings (p ≤ 0.05) were females, greater than 50 years of age, had higher cholesterol levels and more multiple risk factors than comparable males, that more Anglos (p ≤ .005) both males and females, had elevated blood cholesterol levels than did Mexican-Americans but that Mexican-Americans were more obese and exercised less than Anglos.

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