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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

Dynamics of repeated infection of high and low responder inbred mice with Heligmosomoides polygyrus

Maema, Malefane M. January 1986 (has links)
No description available.
142

Experimental study of the host-parasite relationship between the guppy (Poecilia reticulata), and Gyrodactylus turnbulli (Monogenea)

Johnson, Lindsay January 1990 (has links)
No description available.
143

Viral persistence in hepatitis C virus infection

Christie, John Michael Landale January 2001 (has links)
No description available.
144

An analysis of the effects of diet on inflammation, the microbiome, and the relation to offspring

Fontecilla, Natalia 24 September 2015 (has links)
Diet and health are becoming an increasingly important topic in all aspects of society, politics, and everyday life. A growing concern is obesity, which is marked by a large number of circulating fatty acids. This increased number of fatty acids may alter a body's systems such as immune responses. This makes it even more important to scientifically study the effects of one's diet on several factors such as disease, inflammation, and the gut microbiota. Several studies and hypotheses have been performed and proposed, respectively, to find the underlying implications of a high fat diet. Some studies explore the similarity between fatty acids and bacterial antigens, and their resulting stimulation of similar cascades. Others explore the effects of diet on the gut microbiome which has many implications in the context of disease. It has been shown that the microbiota share a relationship with the host that is usually beneficial, but alterations may cause it to become harmful to the host. This manuscript aims to explore these studies and analyze their results, as well as the many connections between them. It also aims to connect these studies with those that explore the far-reaching results of diet, such as the effects it may have on one's offspring. These effects include disease susceptibility and alterations in the gut microbiome in the offspring.
145

Nitroblue tetrazolium: its use in the diagnosis of infection and in the study of leukocytes, lipoproteins and liposomes

Segal, Anthony Walter 14 April 2020 (has links)
A rapid, objective indicator of pyogemc infection would be of great value in the practice of clinical medicine. On the basis of earlier studies it was claimed that the nitroblue tetrazolium ( NBT) test might fulfill such a role. In view of the potential value of this test, it was reassessed m order to determine its diagnostic accuracy and clinical value. The results obtained in this study did not conform with those previously published. Elevated NBT scores were not diagnostic of pyogenic infection, there was a wide overlap of the results of tests performed on patients with pyogenic disease, patients with other diseases and normal subjects. In addition, there was a significant observer error in the interpretation of the slide preparations. The extent of this error was reduced with experience, but was still considerable in the hands of experienced observers. In the NBT test, the dye enters neutrophils by phagocytosis of NBT in particulate form, complexed to heparin and/or '·fibrinogen. The proportion of neutrophils which phagocytose these complexes seems to be related to the severity of illness of the patient. As serum from these patients is capable of enhancing phagocytosis of complexed dye by normal cells, a humeral factor could be responsible for the increased phagocytosis of complexed NBT indicated by a positive test. , Of the compounds tested, man m vitro model system designed to simulate the NBT test, 3 a,l_acid glycoprotein, immunoglobulins and endotoxin, in concentrations that occur in vivo, enhanced NBT reduction. Any one of these compounds, singly or in combination, could be responsible for positive NBT tests.
146

A novel controlled release intravaginal bioadhesive polymeric device

Ndesendo, , Valence Mathias Kessy 28 June 2010 (has links)
PhD Faculty of Health Sciences, University of the Witwatersrand, 2009. / HIV/AIDS was discovered almost a quarter of a century ago and has so far claimed the lives of more than 25 million people worldwide. Developing countries remain disproportionately affected, with sub-Saharan Africa contributing more than two-thirds of infections globally. Sexual transmission is the primary route of HIV/AIDS acquisition, and women bear the greatest burden of this pandemic. We are now at a stage where biotechnological advances are needed that can either cure HIV/AIDS, stimulate the immune system to produce anti-HIV-antibodies by vaccination, or prevent HIV infections. One of these advances has been the development of various microbicides. However, a lack of effective drug delivery systems for these agents has remained as a rate-limiting step towards successful HIV prevention. In an attempt to overcome this problem, this study aimed at designing and developing a novel intravaginal bioadhesive polymeric device (IBPD) as a delivery system to effectively deliver a microbicide {polystyrene sulfonate (PSS)} and antiretroviral (ARV) {3'-azido-3'-deoxythymidine (AZT)} combination to the vagina. The development of a successful intravaginal microbicidal drug delivery system requires the design of a formulation to deliver the microbicide-ARV combination in a safe, effective, and consistent manner. The first step therefore was to undertake extensive preliminary screening studies on various polymeric materials using a one variable at a time (OVAT) approach to find suitable polymers for developing an IBPD. Initially 18 biodegradable and biocompatible polymers were employed to produce 62 formulations that were further screened through the OVAT approach to result in 15 lead formulations. Two major concerns of this study were the attainment of satisfactory residence time of the IBPD in the vagina as well as the ability of the IBPD to contain and release the microbicide-ARV in a controlled manner. Therefore, optimization of the IBPD was based on these two requirements for which proper matrix integrity was a pre-requisite. Artificial neural networks (ANNs), a computational technique that is able to simulate the neurological processing ability of the human brain through mathematical modeling, was employed for optimization. The ANN approach confirmed that 5 of the 18 studied polymers could be suitable for the development of an optimized IBPD. To finally attain good vaginal retention for the developed delivery system, extensive bioadhesivity testing was undertaken on the optimized device. Thorough in vitro and ex vivo bioadhesivity analysis was conducted using physicomechanics and computational structural modeling. Allyl penta erythritolcrosslinked poly acrylic acid (APE-PAA) appeared to contribute most to the bioadhesivity. Apart from being employed as a matrix component, PAA was further used as a coating agent to achieve extended bioadhesivity within the posterior fornix of the vagina. Since prolonged release and suitable permeation of the microbicide-ARV across the vaginal tissue was a critical requirement of this study, the device was designed to provide a controlled and prolonged drug release. Prolonged release for up to 72 days was achieved. Furthermore, the design was constructed to ensure that the released drug could permeate into the vaginal tissue and be retained substantially. This was determined by measuring drug flux through ex-vivo permeation studies using freshly excised pig vaginal tissue in a Franz Diffusion Cell (FDC) apparatus. The ultimate aim of the study was to have the IBPD well accommodated in the vagina for successful prevention of STIs and HIV infection. Achievement of this aim was ensured by undertaking extensive in vivo studies in Large White pig model. The IBPDs were inserted under anaesthesia into the posterior fornix of the vagina, using a novel applicator. To detect the retention of the IBPDs and determine their sequential biodegradation pattern in the vagina, X-ray imaging was employed, using radio-opaque Barium Sulphate (BaSO4). To demonstrate that the developed drug delivery system acted locally and was only minimally absorbed systemically, blood samples were taken from the jugular vein of each pig at pre-determined time intervals and subjected to UPLC analysis. The drug content in the vaginal tissue at the end of the study was also determined. Histopathological evaluation was carried out on vaginal epithelium to access the potential for toxicity of the IBPDs. The drug content analysis revealed that greater amounts of AZT and PSS were retained in the vaginal tissue with relatively small quantities (AZT:17%; PSS:13%) crossing into the systemic circulation. The results from the toxicity studies showed that the IBPDs were safe for use. This suggests that the developed drug delivery system (the IBPD) may be suitable for application in the prevention of STIs and HIV infections.
147

Knowledge, attitudes and practices of general assistants towards infection control at Letaba Hospital

Peta, Mmalahla Rebecca 26 March 2015 (has links)
A research report submitted to the Faculty of Health Science, University of the Witwatersrand as partial fulfilment of the requirement of the degree in Masters of Public Health (Hospital Management) November 2014. Johannesburg, South Africa / Introduction - The implementation of infection prevention and control guidelines is important for the improvement of quality care in hospitals. This study aimed to identify gaps in the knowledge and attitudes of general assistants about infection control and to determine if their infection control practices are in line with current policies and guidelines. In investigating the practices of general assistants, the institution was assisted to identify gaps in knowledge and try to strengthen practices. Methodology: This descriptive cross-sectional study was conducted at Letaba hospital in Mopani district. The knowledge, attitudes and practices of 97 general assistants towards infection control at a given point in time was measured through a structured questionnaire which was administered to those who consented to participate. Purposive sampling was used as only those who were at work during the data collection period were included in the study. Results - This study revealed that over 50% of general assistants at Letaba hospital have only moderate knowledge about infection control. Fifty seven percent of general assistants reported moderately good infection control practices, while 23% practice infection control poorly. The majority (75%) of general assistants at Letaba hospital reported positive attitudes towards infection control. The results also show that the moderate score in knowledge affected the practice of infection control. Conclusion - This study shows that the knowledge and practice of infection at Letaba hospital is not optimal with regard to complying with infection control guidelines. It was, however, noted that attitudes towards infection control were good. Based on the fact that the attitudes were good, knowledge and practice can be improved with provision of appropriate supplies and strengthening training and supervision.
148

The development of a comprehensive infection prevention quality audit tool for operating room theatres in a private health care environment

Engelbrecht, Linette January 2017 (has links)
A Dissertation submitted to the Faculty of Health Science, University of the Witwatersrand, in fulfillment of the requirements of the degree of Master of Science in Nursing Education Johannesburg, June 2017 / Multi-resistant organisms, the involvement of numerous stakeholders in the OR as well as the complex procedural and technical advancements, especially in the private healthcare environment, justifies an evidence based infection prevention quality audit tool for an OR that is comprehensive. The purpose of the study was to develop a comprehensive infection prevention quality audit tool for operating room within a private healthcare environment. A three phased, multi-method study was conducted whereby phase one included the identification of statements in existing audit tools, policies and published articles. This was used to compile concourse statements that were used during phase 2 in the Q-sort data collection method, which allowed stakeholders (scrub- and anaesthetic nurses, CSD Managers, IPC- and OHS Coordinators and surgeons) to indicate what they want to be included in the IPC Audit Tool for operating room. A statement verification was conducted to expand the concepts that enabled the researcher to compile an audit tool. Subject experts and the researcher tested the degree of validity of the audit tool in phase three of the study. A descriptive analysis revealed that the results of the Q-sort event was inconclusive. The subject experts were unable to determine the degree of validity of the audit tool, which forced the researcher to test the audit tool in an OR. A Comprehensive IPC Control Quality Audit Tool was developed. The utilisation of the audit tool in an OR should be a well-planned event. Specific education and training of the multidisciplinary team regarding IPC in the OR should be considered. / MT2017
149

Microbial evaluation of an alternating pressure pad from an infection control viewpoint.

McLaughlin, James Peter 01 January 1980 (has links) (PDF)
No description available.
150

TOWARD MOLECULAR IMAGING PROBES TO DETECT CRYPTIC BACTERIAL INFECTIONS

LLANO PIEDRA, LISSET BARBARA 06 1900 (has links)
Infectious diseases represent one of the leading causes of death globally. Prompt diagnosis is essential for the onset of clinical treatment but certain cases of underlying bacterial infection deep in the body can remain undiagnosed for weeks. Hidden bacterial infection is the leading cause of fever of unknown origin (FUO), which is observed in 2 % of all hospital admissions around the world. Molecular imaging of bacterial infections is the ideal non-invasive diagnostic tool, but all available probes also detect inflammation. Two targets were selected for development of bacteria-specific molecular imaging probes, namely iron-uptake pathways and peptidoglycans involved in the synthesis of the cell wall. Both, Gram-positive and Gram-negative bacteria use iron-binding molecules called siderophores to scavenge iron from their surroundings. The structural similarities between Fe3+ and Ga3+ allow siderophores to be radiolabelled with 67/68Ga and visualized by nuclear medicine techniques. The clinically proven siderophore Deferoxamine (Dfo) has a plasma half-life of only 5.5 min that does not favor its direct use as a probe. Dfo derivatives with improved pharmacokinetics properties were designed and tested on Staphylococcus aureus cultures. The ciprofloxacin and the ethyloxycarbonyl derivatives of DFO at the primary amino position were among the most successful conjugates targeting the siderophore active-transport mechanism and reaching high relative uptake rates. Furthermore, the peptidoglycan pathway of Gram-positive bacteria was in vitro targeted with vancomycin conjugated to 67Ga-Dfo which showed even higher labelling capacity than 67Ga-Dfo within a few minutes of exposure. In vitro siderophore studies remain challenging due to the lack of methods for the preparation of rigorously iron-depleted media. We developed an iron chelating method with the goal of creating iron-free growth media. / Thesis / Master of Science (MSc)

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