• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2480
  • 1716
  • 324
  • 233
  • 165
  • 163
  • 118
  • 92
  • 76
  • 39
  • 31
  • 26
  • 21
  • 10
  • 8
  • Tagged with
  • 6261
  • 1598
  • 1503
  • 1499
  • 1249
  • 547
  • 374
  • 357
  • 334
  • 331
  • 316
  • 305
  • 298
  • 297
  • 291
  • 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.

Pre-operative localization and surgical outcomes for primary hyperparathyroidism (PHPT): An 11-year review at a South African hospital

Van Wyngaard, Tirsa 04 February 2019 (has links)
Introduction: Primary Hyperparathyroidism (PHPT) is characterized by hypersecretion of PTH leading to hypercalcaemia with successful surgery being the only definitive cure. Broadly, three techniques of parathyroidectomy exist: open bilateral neck exploration and minimally invasive parathyroidectomy, which is subdivided into open focused approaches and endoscopic focused approaches. A focused parathyroid gland exploration guided by pre-operative imaging is associated with less morbidity compared to a bilateral approach. Focused explorations may target either the side or the specific parathyroid gland identified. Aim: The primary aim of this study was to evaluate the accuracy of pre-operative localisation for PHPT in a single centre. The secondary aim was to review the type of parathyroid surgery performed and the final Parathyroid Hormone (PTH) levels in patients who have undergone parathyroidectomy for PHPT. Methods: This is a retrospective review of all patients who underwent primary surgery for PHPT between 2005 and 2015. Patients were identified from a general operative database. Data was collected from pathology records, operative notes, nuclear medicine and radiology reports and captured on a confidential data sheet. Results: Records of 98 patients were found and included. Sestamibi had a sensitivity of 88%, a positive predictive value of 83% and an accuracy of 75%. Ultrasound had a sensitivity of 52%, a positive predictive value of 78% and an accuracy of 44%. The total number of cases in which both ultrasound and sestamibi were done was 73. Sestamibi and ultrasound showed concordant results in 25 cases. The overall surgical success rate was 94% (92/98). The cure rate for patients in whom sestamibi and ultrasound were concordant, was 96% (24/25). The minimum and maximum calcium levels in the cohort were 2.2 and 4.41 respectively, with a mean of 2.86. PTH levels ranged between 4.2 and 186 with a mean of 33.8. One double adenoma was proven on histology. The rest were all single adenomas. The total number of malignancies were 3 of which 1 was part of a MEN syndrome. Conclusion: Our surgical success rate was 94%. When imaging modalities were concordant, surgical success was achieved in 24 cases, thus in 96% of the subgroup. Our figures compare favourably with international standards. There is scope for improvement in the accuracy of both ultrasound (46%) and sestamibi (75%) localization. Currently a combination of both imaging modalities is still recommended.

Separation and purification of mucins and tenascin-C in breast milk of patients and the investigation of the role of mucins and tenascin-C in the inhibition of HIV-1

Kehoe, Kathleen January 2017 (has links)
An estimated 36.7 million people were living with HIV in 2015, with 2.1 million newly infected people with HIV in 2015 worldwide. The highest prevalence of HIV in 2015 was in the Eastern and Southern African regions. This highlights the importance for research in this field to further prevent the number of new HIV cases. Mother-to-child transmission of HIV is due to either cell-associated or cell-free virus present in the breast milk of an HIV positive mother. Most often, HIV positive mothers choose to breastfeed their infants due to the nutritional and immunological benefits outweighing that of the risk of HIV transmission. Importantly, approximately 85% of infants do not acquire HIV through daily exposure to breast milk from their HIV positive mothers who are not on ART suggesting that human breast milk has antiviral properties. Previously in our laboratory, MUC1 and MUC4 has been implicated in the inhibition of HIV-1 in an in vitro assay. Furthermore, crude breast milk was tested in this assay showing strong HIV-1 neutralisation. Pasteurisation (80°C for 10 minutes) of both HIV positive and negative breast milk indicated good neutralisation of HIV-1 in our laboratory. Another breast milk protein, tenascin-C (TNC), was recently shown to strongly neutralise HIV-1 in a study performed by another group. Therefore, with this knowledge, this study was employed to firstly compare the antiviral properties of MUC1, MUC4 and TNC. Furthermore, the HIV-1 neutralisation ability of crude breast milk was sought to be investigated along with the investigation of two different pasteurisation methods including 80°C for 10 minutes and 62.5°C for 30 minutes (Holder pasteurisation). Human breast milk was separated into milk fat and skim milk using caesium chloride density gradient ultracentrifugation. MUC1 was purified from the milk fat using gel extraction from a 4-20% sodium dodecyl sulphate polyacrylamide gel. The skim milk was chromatographed on a Sepharose 2B-CL column from which the void volume was collected to purify TNC using gel extraction from a 4-20% sodium dodecyl sulphate polyacrylamide gel. During this purification, a band consisting of MUC1 which adhered to TNC was used to co-purify the MUC1/TNC glycoprotein using gel extraction. MUC1 and TNC were individually purified using gel extraction. MUC4 was not successfully purified and from ELISA data it was concluded that the concentration of MUC4 was below the detectable limit of the ELISA kit. The average concentration of MUC1 was determined to be 307.85 ng/ml, while the concentration of TNC could not be determined due to the majority of absorbance values (450 nm) lying above the upper limit of the curve. The HIV neutralisation of each of the samples was tested in an in vitro HIV-1 assay. This assay utilises a luciferase reporter gene in modified TZM-bl/JC cells using Du422.1 virus derived from clad C of HIV-1. These assays are being performed to assess the antiviral properties of crude and heat treated breast milk and purified MUC1 and TNC separately as well as co-eluted and co-purified MUC1/TNC. The two pasteurisation methods increased the HIV-1 neutralisation when compared to crude breast milk. The HIV-1 neutralisation of these groups were compared with a Kruskal Wallis test and a statistically significant difference was detected among the crude and 62.5°C heat treated breast milk cohorts (Mann-Whitney U, p-value = 0.0021). Furthermore, a statistically significant difference in the HIV-1 neutralization was detected among the 80°C and 62.5°C heat treated breast milk cohorts (Mann-Whitney, p-value = 0.0033). From the data, and the range of IC₅₀ values (50% inhibitory concentration), the HIV-1 potency was deemed the strongest in the 62.5°C heat treated breast milk. This pasteurisation method could potentially be promoted in lower resource settings to decrease mother-to-child transmission of HIV-1. Purified MUC1 and TNC, as well as co-eluted and co-purified MUC1/TNC, was tested in the same neutralization assay in order to compare the HIV-1 potency of these glycoproteins. The difference in HIV-1 neutralisation was not statistically significant among all three groups (Kruskal Wallis, p-value = 0.13). From the range of IC₅₀ values, it was suggested that TNC has a stronger HIV-1 potency when compared to MUC1. Overall, the co-eluted and co-purified MUC1/TNC showed a lower HIV-1 potency when compared to the single, purified glycoprotein. MUC1 and TNC could be purified and cloned to aid in the protection against contracting HIV-1, especially in mother-to-child transmission of HIV-1. Histochemistry and immunohistochemistry was performed on breast tissue sections to investigate the morphology of the cells and the presence of MUC1, MUC4 and TNC respectively. The lactating breast tissue was confirmed to have wide, dilated lumina and vacuolated cytoplasm with neutral and sialomucins. The presence of MUC1, MUC4 (β subunit) and TNC were confirmed in the lactating breast tissue using immunohistochemistry.

Investigations into the stability of growth factor induced-vasculature and the effects of synthetic biomaterials on heart remodelling after myocardial infarction

Dobner, Stephan January 2011 (has links)
This work was based on the hypothesis that optimization of growth factor delivery rate and duration, combined with a biomaterial scaffold, could lead to an improved strategy for therapeutic neovascularization. To test this hypothesis, a novel in vivo model system that allows for characterization of stability and mural cell investment of newly created vessels was designed.

Complications of anti-reflux surgery in gastro-esophageal reflux disease with special reference to dysphagia

Brink, Abraham Justinus January 2009 (has links)
Includes bibliographical references (leaves 40-48). / All patients who underwent revision laparoscopic surgery from January 202 to July 2008 in the UCT Private Academic /Groote Scruur Hospital complex for intractable dysphagia and who did not respond to consevative treatment were reviewed. Patients with peri-oesophagel fibrosis as the dominant cause for their dysphagia were identified during surgrry and closely followed up. This study was focused on those patients' pre- and post-operative course.

The interaction between exercise induced muscle damage and fatigue on neural regulation and exercise performance during submaximal and maximal running

Noel, Colin Byron 19 February 2019 (has links)
Aim: To study the effects of muscle damage and fatigue on neuromuscular preactivation and performance during submaximal and maximal running. Setting: University of Cape Town, Sports Science Institute of South Africa. Methods: 12 male distance runners (19 - 39 years of age) with a minimum weekly training distance of 40 kilometers per week were randomly assigned to either control (n = 6) or experimental (n = 6) groups. Subjects’ visited the laboratory over an 11 day period during which testing included a submaximal and maximal run (5 km time trial) on the first and last day of testing. Neuromuscular preactivation, rating of perceived exertion, heart rate and performance times were recorded during the performance trials. The intervention between performance trials included two 40 minute bouts on a treadmill at 70 % peak treadmill running speed at –10 º elevation (experimental) or horizontal (control). Results: Running performance in the 5 km time trial (5K) improved in the experimental group alone by an average of 40 seconds over 5 km (P < 0.04) in the presence of muscle damage and without altered neuromuscular preactivation. There was no evidence any interaction between altered neuromuscular activity with regard to fatigue and muscle damage during submaximal and maximal running. Evidence of muscle damage in the experimental group was supported by a significant group versus time interaction effect in subjective pain score for daily living and increased plasma creatinine kinase levels in the experimental group (P<0.03). A significant decrease in rating of perceived exertion (RPE) was observed in both groups during both the submaximal (P<0.04) and 5 km time trial (P<0.03) post intervention. There was an interaction effect for group versus pre-post 5K (P<0.06), with the post 5K RPE in the experimental group showing an average decreased RPE score of 2.6 for each kilometer and the control group an average decrease in RPE score of only 0.03. Conclusion: The research design of this study was appropriate to study the interaction between fatigue and muscle damage during submaximal and maximal running. This study suggests that there is no neuromuscular compensation after muscle damage and that EMG is regulated similarly for both fatigue and muscle damage during submaximal and maximal running. Improvement in running performance and decreased rating of perceived exertion after muscle damage is due to some unknown variable.

A retrospective audit of the outcomes of the Fellow Of College Of Surgeons (FCS) (General Surgery) Final Examinations

Kahn, Miriam 19 February 2019 (has links)
Background and aim: An audit of the Fellowship of the College of Surgeons FCS (SA) Final Examination results has not been previously performed. The purpose of this study was to review and determine any predictors of outcome. Methods: The results of the FCS (SA) Final Examinations from October 2005, to and including, October 2014, were retrieved from the College of Medicine of South Africa database. The current format of the examinations consists of: two written essay question papers, an OSCE, two clinical cases and two vivas. These were retrospectively reviewed and analyzed. Predictors of failure or success were determined. Analysis was performed using IPython for scientific computing. Assumptions for the normal distribution of numerical values were made based on the Kolmogorov-Smirnov test and quantile-quantile plots. Normally distributed variables were analyzed by parametric tests. In all other cases nonparametric tests were employed. An alpha value of 0.05 was chosen to indicate statistical significance, using a confidence level of 95%. Results: During the 10-year study period, 472 candidates attempted the examinations. A total of 388 (82,2%) candidates were successful in the written component of the examination and were subsequently invited to participate in the oral/clinical component of the examinations. 9 Overall, 296 (62,7%) of candidates passed and 176 (37,3%) failed. A total of 19 candidates achieved less than 50% for both papers, yet still managed an average of more than 45%. A total of 15 (79%) of these candidates went on to fail the examination. There were 51 candidates who were invited to the oral examinations despite an average of less than 50% in the two papers, and 34 (67%) failed the overall examination. Similarly, 126 candidates were invited having failed one of the two papers of which 81 (64.3%) ultimately failed. A total of 49 candidates failed the OSCE, 82% of these candidates failed overall. There was strong correlation between paper one and paper two (r = 0.56, p-value < 0.01), oral one and oral two (r = 0.41, p-value < 0.01) and case one and case two (r = 0.38, p-value < 0.01). Similar correlations were seen between the averages of the papers versus the orals (r = 0.52, p-value < 0.01), the papers versus the cases (r = 0.5, p-value < 0.01) and the papers versus the OSCE (r = 0.54, p-vale < 0.01). Conclusion: The written papers are the main determinant of invitation to the second part of the examination. Candidates with marginal scores in the written component had an overall failure rate of 67%. Failing one paper and passing the other, resulted in an overall failure rate 64,3%. Failing the OSCE resulted in an overall 82% failure rate. With the high failure rate of candidates with marginal scores and with the inter-examination variability of the papers, it might be prudent to revisit both the process of invitation selection and the decision to continue with the long-form for the written component.

Flow velocity measurement in haemodialysis access using 4D MRI

Downs, Jennifer January 2016 (has links)
Treatment of renal failure while awaiting transplant requires vascular access, which comes with both complications and failure rates. In order to improve this, information about the AVF or AVG itself, as well as the haemodynamics is required. This data will then be used for computer modelling techniques and computational flow dynamics. Previously, the required imaging was provided by contrasted MRI, contraindicated in renal failure. Haemodynamic data was prvided by, amongst other things, duplex Doppler. New MRI software that provides imaging data as well as haemodynamic information without using contrast could be used to provide new high-quality data for modelling. Methods: This was a prospective pilot study. Six control cases (with no history of vascular illness or surgery of any kind to the right upper arm), as well as three grafts and five fistulae underwent phase contrast MR angiography of the right upper arm with a Siemens Magnetom Symphony 1.5T MRI Scanner. Images were then processed using Supertool in Matlab, and flow velocities at predetermined points on the brachial artery and cephalic vein, graft and fistula were calculated. Results: Velocities ranged from 5.8 cm/sec in a volunteer's brachial artery to 85.5 cm/sec in an arteriovenous fistula patient's brachial artery. Flow volumes in the cephalic vein or access varied from 6.9 ml/min. in a volunteer and up to 4398.1 ml/min. in an arteriovenous fistula. Graphical representations show marked haemodynamic changes throughout the imaged vessels. Conclusion: This technique provides good imaging and quantitative data about small vessel haemodynamics.

Global surgery - socioeconomic and geographic maldistribution of surgical resources

Dell, Angela June January 2016 (has links)
Surgery is an indispensable part of any health system and improving access to safe surgery remains a challenge in the developing world. Surgery is emerging as a priority in global health, unfortunately information around the burden of surgical diseases or the available surgical resources is limited. South Africa is an Upper Middle Income Country (UMIC) and currently provides reasonable surgical services, however these services vary across regions, between urban and rural settings, as well as between public and private hospitals. There is no reliable data regarding the available surgical resources in South Africa, namely surgical beds, operating theatres and surgeons. These variables are essential in developing a National Surgical Plan to address the burden of surgical disease, however they are limited in the information they provide they provide regarding surgical capacity and need to be assessed in context with more robust indicators. This aim of this study was to quantify some of the specific surgical resources as identified by the World Health Organization (WHO) and the Lancet Commission. This research will contribute to the growing body of research regarding global surgery in South Africa and attempt to provide an analysis of metrics used to evaluate surgical systems. The research hypothesis was that the surgical resources in South Africa were limited, and that surgeons, theatres and hospital beds per capita are inadequate compared to developed countries and do not meet global recommendations. This involved a descriptive analysis of surgical resources and included the total number of hospitals, of hospital beds, the number of surgical beds, the number of general surgeons (specialist and non-specialist), and the number of functional operating theatres in South Africa. The surgical resources were analysed, both according to province and district, and a comparison was performed based on the population density. A comparison of the public and private facilities was undertaken with regard to the total numbers, as well as per population density. Lastly, a comparison was performed with other high and low income countries around the world. The results showed one hospital per 100 000 population, 186.64 hospital beds, 41.55 surgical beds, 1.78 specialist general surgeons, 2.90 non-specialist general surgeons, and 3.59 operating theatres per 100 000 people in South Africa. These numbers fell far below international recommendations, as well as developed countries such as the United Kingdom (UK) and United States of America (USA). Surgical resources were concentrated in metropolitan areas, and there were differences between the public and private sectors, with private hospitals having a greater number of surgical beds and operating theatres per population than public hospitals. These data indicated how surgical providers and basic infrastructure were distributed in South Africa, which will allow more accurate planning by government policymakers. Recommendations need to be tailored according to each sector as the needs of the patients and resources available are different. There is a need to acknowledge the major shortage of healthcare providers with implementation of the National Health Insurance (NHI). There is a need for validated instruments to accurately collect data and for reliable electronic information sharing which will improve data collection and analysis between rural and urban areas. Existing resources need to be utilized more effectively. These results showed that regional hospitals lack both specialist and non-specialist general surgeons. The international consensus was that performing surgery at district level hospitals improved access and lowered cost, however this will need recruitment of additional skilled personnel and infrastructure in order to support surgery at this level. This national audit has provided much needed data on the some of the available surgical resources may influence critical decision-making about funding distribution, resource and training post allocations, as well as address inequalities in service delivery.

Changes in behavior and self-perceived breast cancer risk after an education session andbreast cancer risk assessment

Magnante, Alexandra 11 July 2019 (has links)
No description available.

The biochemical analysis of mucus and mucins in respiratory diseases with a focus on tuberculosis

Mofokeng, Henrietta Refiloe January 2016 (has links)
Respiratory diseases are a major cause of death in South Africa, with TB being one of the major respiratory illnesses. The respiratory tract is lined by a layer of mucus which protects the airways and lungs against injury by foreign agents. The main constituents of this layer of mucus are mucins. MUC5AC and MUC5B are the predominant respiratory tract mucins. However, little is known of the association between respiratory mucins and TB. This study aimed at describing the types and role of respiratory mucins in TB. Fifty six sputum samples, 17 tracheal aspirates and 95 bronchoalveolar lavages (BALs) were collected in 6M guanidinium hydrochloride and inhibitors. The airway mucus was divided into TB and non-TB groups. Mucins were reduced and alkylated with DTT and iodoacetamide and purified by density gradient ultracentrifugation in caesium chloride. Identification of MUC5AC, MUC5B, MUC2 and MUC7 were determined by western blotting and confirmed by immunohistochemistry. Western blot data proved the dominance of MUC5AC and MUC5B mucins in airway mucus. In comparison to the non-TB group, a higher secretion of MUC5AC than MUC5B in patients with TB was observed. MUC5AC also showed distinct behavioural characteristics in its fractionation in a caesium gradient compared to MUC5B. The presence of MUC5AC and MUC5B in different fractions suggests varying glycosylation of the mucin. Varying populations of MUC5B were observed in sputa with 3 new glycoforms shown in TB. A small group of TB patients had MUC7 in the sputa (and not in the lavage) and there were varying amounts of MUC2 in some TB samples and non-TB mucus. At tissue level, MUC5B was found to be the main secreted gel-forming mucin. MUC5B and MUC7 were found to play a role in the protection again infection by Mycobacterium tuberculosis in tuberculous granulomas. Using proteomics it was demonstrated that respiratory mucus protein expression differs in, tracheal aspirates, BALs and sputa. Although inter-individual variations were observed in all samples, similar proteins were expressed in relation to the functioning of the lung. O-glycan analysis showed that the majority of the O-glycans detected were sialylated and that core 3 and 4 O-glycan structures diminished in the presence of HIV.

Page generated in 0.035 seconds