Typescript, etc.

Thesis (Ed.D.)--Teachers College, Columbia University, 1994. / Typescript; issued also on microfilm. Sponsor: O. Roger Anderson. Dissertation Committee: Patricia L. Dudley. Includes tables. Includes bibliographical references (leaves 119-129).

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. "December 2007" Includes bibliographical references.

Digitized by Kansas Correctional Industries

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Health Sciences. Includes bibliographical references (leaves 139-154)

Prophylactic administration of the immunosuppressive drug cyclosporine A protects Balb/c mice from fatal Leishmania major infections. It is believed that distinct subpopulations of CD4+ T lymphocytes and their distinctive cytokines may determine susceptibility and resistance to leishmaniasis among inbred strains of mice. CsA may enhance disease resistance in Balb/c mice by modulating these T cell subsets and/or their cytokines. We have measured lymphoid cell production of IL-2, IL-4, and TNF-a in naturally resistant C57/Bl/6, CsA-treated Balb/c, and nontreated Balb/c mice during the course of L. major infection. CsA treatment inhibited IL-2 and IL-4 production for the first week of infection. Thereafter the cytokine production of all three groups of mice did not differ greatly except in week two when the treated mice produced significantly enhanced levels of IL-4. C57B1/6 mice did produce slightly more TNF-a than either group of Balb/c mice, but as the CsAprotected and diseased Balb/c mice produced similar amounts of this cytokine, the elevation in C57B1/6 animals probably reflects a strain-related difference rather than disease resistance. / Department of Biology

A caracterização da síntese de fosfatidilserina (PS) em Leishmania (Leishmania) amazonensis mostrou a presença de uma única via de síntese de PS, pela ação da enzima fosfatidilserina sintetase II (PSS II). A seqüência que codifica essa enzima, presente em cópia única no genoma, apresentou uma identidade de 38% e uma similaridade de 55% com seu homólogo humano. Tentativas de se nocautear esse gene não foram bem sucedidas, indicando que o gene é essencial à sobrevivência do parasita. Ensaios de incorporação de fosfolipídios marcados mostraram que o parasita captura do meio fosfatidiletanolamina, substrato da PSS II, mas a incorporação de PS se dá em uma taxa muito baixa. Também foi feita a caracterização do transporte de serina pelo parasita, que mostrou a existência de um único transportador com pH ótimo de 7,5, dependente da aitvidade metabólica da célula, com um Km de 0,826 +/- 0,183 mM e Vmax de 355,37 +/- 19,41 pmol/min * 2 * 107 promastigotas, que se mantém ativo a até 45 oC. / The characterization of phosphatidylserine (PS) synthesis in Leishmania (Leishmania) amazonensis revealed a single pathway that presented phosphatidylserine synthase II (PSS II) activity. The single copy gene that encoded this enzyme showed 38% of identity and 55% of homology to the human homolog. Attempts for the gene knockout were not successful, indicating that the gene is essential for the parasite survival. Incorporporation assays of labeled phospholipids showed that the parasite take phosphatidylethanolamine, substract for the PSS II, from the medium, but the rate of incorporation of PS occurred at a very low rate. The biochemical characterization of the serine incorporation by the parasite showed the existence of a single transport system, with an optimum pH of 7.5, which was dependent of metabolic activity of the cell, that showed a Km of 0.826 +/- 0.183 mM and Vmax of 355.37 +/- 19.41 pmol/min *2 * 107 promastigotes, that remained active up to 45oC.

A caracterização da síntese de fosfatidilserina (PS) em Leishmania (Leishmania) amazonensis mostrou a presença de uma única via de síntese de PS, pela ação da enzima fosfatidilserina sintetase II (PSS II). A seqüência que codifica essa enzima, presente em cópia única no genoma, apresentou uma identidade de 38% e uma similaridade de 55% com seu homólogo humano. Tentativas de se nocautear esse gene não foram bem sucedidas, indicando que o gene é essencial à sobrevivência do parasita. Ensaios de incorporação de fosfolipídios marcados mostraram que o parasita captura do meio fosfatidiletanolamina, substrato da PSS II, mas a incorporação de PS se dá em uma taxa muito baixa. Também foi feita a caracterização do transporte de serina pelo parasita, que mostrou a existência de um único transportador com pH ótimo de 7,5, dependente da aitvidade metabólica da célula, com um Km de 0,826 +/- 0,183 mM e Vmax de 355,37 +/- 19,41 pmol/min * 2 * 107 promastigotas, que se mantém ativo a até 45 oC. / The characterization of phosphatidylserine (PS) synthesis in Leishmania (Leishmania) amazonensis revealed a single pathway that presented phosphatidylserine synthase II (PSS II) activity. The single copy gene that encoded this enzyme showed 38% of identity and 55% of homology to the human homolog. Attempts for the gene knockout were not successful, indicating that the gene is essential for the parasite survival. Incorporporation assays of labeled phospholipids showed that the parasite take phosphatidylethanolamine, substract for the PSS II, from the medium, but the rate of incorporation of PS occurred at a very low rate. The biochemical characterization of the serine incorporation by the parasite showed the existence of a single transport system, with an optimum pH of 7.5, which was dependent of metabolic activity of the cell, that showed a Km of 0.826 +/- 0.183 mM and Vmax of 355.37 +/- 19.41 pmol/min *2 * 107 promastigotes, that remained active up to 45oC.

Thesis (MSc (Veterinary Tropical Diseases)--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

This study was carried out to investigate different aspects of the epidemiology of the common intestinal protozoan infections in children in KwaZulu-Natal. The main aspects studied were to: i . monitor changes in the prevalence and intensity of the common intestinal protozoons in children after receiving antihelmintic drugs, ii. determine whether environmental and/or socio-economic factors are important in the prevalence of the common intestinal protozoons, iii. determine the occurrence of Cryptosporidium parvum in stool samples of paediatric patients with gastroenteritis and in healthy school children. Intestinal protowan species often co-occur with intestinal nematodes in infected children and it is important to determine the effect that anti-nematode treatment has on concomitant protozoan infections. The study included the analysis of stool samples by the Formol-Ether Concentration Technique, exam ination of the obtained sediments for intestinal helminths and protozoan species, and treatment of nematode-infected individuals. Four surveys were carried out to determine the prevalence and intensity of intestinal protozoons in school children before and after anthelmintic chemotherapy, and the X(2) test was used to determine significant changes. Prevalences and intensities of helminths were determined for significant changes after treatment using the Student's t-test. Additional pre- and post-treatment prevalence data were obtained from four schools in Health Region A of KwaZulu-Natal. The prevalence of Ascaris lumbricoides decreased significantly from 75.2% to 9.7% after the first treatment, that of Trichuris trichiura decreased from 77.7% to 62. 1%, and hookworm infections (presumably Necator americanus) dropped fromI2.7% to 1.0% and remained very low for the rest of the study. Very few individuals were infected with protozoan species and for statistical analysis, these were combined. The prevalence of protozoan infections increased from 33.0% to 50.3% after the first treatment and from 35% to 42% after the second treatment. The prevalence of A. lumbricoides decreased significantly again after the second treatment while there was no significant decrease in the prevalence of T. trichiura. The intensities (number of eggs/gram of feaces) of the three nematodes also decreased significantly after the two treatments. It is recommended that children who have been treated for nematode infections should also be examined for protozoan infections, and these should also be treated accordingly. A retrospective analysis of protozoon prevalence data from different surveys in KwaZulu-Natal was done in order to detennine the importance of environmental and/or socio-economic factors in the distribution of intestinal protozoons. These data were plotted on the map of KwaZulu-Natal using Geographic Information System (GIS). Univariate analysis was carried out to determine significant correlations between the prevalences of protozoan species and selected variables. The significant correlations obtained were moderate and no strong correlations were obtained. Univariate stepwise regression analysis was performed to determine the factors that combine best in facilitating the transmission of protozoan species and significant associations were obtained between the prevalence of protozoon species and a combination of environmental and socio-economic factors. In most cases, the association between prevalence and mid-summer temperature and rainfall were the most significant. This is an indication of increased summer transmission. Altitude was significantly correlated only with the prevalence of Endolimax nana. The fact that moderate correlations were obtained between prevalence of intestinal protozoons and climatic and socio-economic factors indicates that these factors are important in the distribution of the common intestinal protozoons. However, lack of strong correlations suggests that in addition to climatic and socio-economic factors, there are other factors that have an effect on the distribution of intestinal protozoan species. In the multivariate analysis where the variables were simultaneously considered, the presence of electricity was the only factor that was significantly associated with the variation seen in the prevalence of intestinal protozoons in the different study locations. Cryplosporidium parvum is a parasitic protozoon that is associated with severe fatal diarrhoea in children and immunocompromised individuals. Oocysts of this parasite were found in 18.2% of stool samples collected from children (aged 6 to 48 months) who were admitted in the paediatric wards at King Edward VIII Hospital, Durban. The stool samples were firstly concentrated using the Formal-ether method and the obtained sediment was mixed with the Sheather's Sucrose solution and examined microscopically. No oocysts were found in stool samples collected from older primary school children. Although the diarrhoea in these children might have also been due to other causes, the results obtained further show the importance of C. parvum as a cause of diarrhoea in children below the age of five years. Knowledge of the epidemiology of C. parvum is crucial in the control of this parasite as there is currently no effective treatment. More intensive surveys are needed in detennining the epidemiology of this pathogen in the South African population. / Thesis (M.Sc.)-University of Natal, Durban, 2001.