Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 175-194).

Thesis--Universidad de Sevilla. / "Apéndice demografico": p. 134-180. Includes bibliographical references (p. 132-134).

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.

Thesis--Universidad de Sevilla. / "Apéndice demografico": p. 134-180. Includes bibliographical references (p. 132-134).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 151-169).

No description available.

Cholera is an acute diarrheal illness burdening several developing countries caused by toxigenic Vibrio cholerae, where endemics maintain a seasonal pattern and occur more than once a year. Cholera is endemic in certain regions of Africa and South America, and southern Asia, where outbreaks are associated with poor hygiene and sanitary conditions. Every year, 3–5 million cases of cholera are diagnosed, and it causes more than 100,000 deaths worldwide. Cholera toxin is secreted by the V. cholerae bacteria and causes extreme secretory diarrhea, most commonly in poor hygiene environment. Watery diarrhea, vomiting, and abdominal cramps characterize the illness and approximately 5–10% of patients die of severe fluid loss if left untreated. The structure and function of the cholera toxin, its subunits, receptor, and impact on hyperactivation of cyclic adenosine monophosphate (cAMP) were sufficiently described in the 1970s. These findings fit with epidemiologic observations, which determined that the cholera toxin must first enter intestinal cells by binding to monosialoganglioside (GM1) on the host’s epithelial surface. The correlation between increase risk of V. cholerae infection and individuals with a particular ABO blood group type is unclear because of the scarce information and few studies conducted. Thus, this study reviews published research articles to better understanding the association between the blood group O and susceptibility to developing severe cholera symptoms. Several large studies have recorded an association between ABO blood groups and different infectious agents). Anthropological surveys suggest that the racial and geographic distribution of human blood types reflects tendencies towards specific erythrocyte types susceptible to infectious disease, such as cholera and malaria. Experimentally, the V. cholerae toxin has been extensively used as an experimental adjuvant, and its association with ABO groups is of practical importance for the development of an oral cholera vaccination. The results of previous studies provided strong evidence that individuals with blood type O are more vulnerable than other persons to severe cholera symptoms, even though the biologic basis for this association remains unknown.

nÃo hà / As taxas de morbimortalidade se elevam quando a diarreia està associada à desnutriÃÃo. Entretanto, os mecanismos pelos quais as deficiÃncias nutricionais afetam o intestino sÃo em grande parte desconhecidos. O objetivo desse trabalho foi avaliar alteraÃÃes morfomÃtricas, nas proteÃnas transportadoras de substratos e no transporte intestinal de eletrÃlitos e Ãgua em modelo de desnutriÃÃo em camundongos. Objetivamos ainda, analisar o efeito da toxina do cÃlera (TC) associada ou nÃo à desnutriÃÃo, sobre as proteÃnas transportadoras de substratos, sobre o transporte hidroeletrolÃtico em camundongos e por fim, avaliamos os efeitos de soluÃÃes de reidrataÃÃo oral (SRO) da OMS (SGli) e modificadas com glutamina (SGln), alanil-glutamina(SAla-Gln) e arginina (SArg) nesse transporte. Camundongos (n=20) receberam por 7 dias uma raÃÃo deficiente em proteÃnas, gorduras e minerais (DBR). Segmentos de Ãleo foram obtidos antes e no 7 dia da dieta, para estudos de morfometria, imunohistoquÃmica para as proteÃnas: SGTL-1, PepT-1, CAT-1 e SN-2 e avaliaÃÃo por RT-qPCR da expressÃo RNAm dessas proteÃnas transportadoras. O modelo de perfusÃo intestinal por 75 min em camundongos (n=6) foi utilizado para avaliar o transporte intestinal de Ãgua e eletrÃlitos e para avaliar o papel de soluÃÃes de reidrataÃÃo oral em camundongos nutridos e desnutridos expostos ou nÃo à toxina do cÃlera (1Âg/ml). Animais desnutridos apresentaram perda ponderal, atrofia dos vilos e reduÃÃo na expressÃo por imunofluorescÃncia da SGTL-1. A desnutriÃÃo causou ainda reduÃÃo na expressÃo do RNAm da SGTL-1 e PEPT-1 e aumento na expressÃo do RNAm para o SN-2 no ileo de camundongos. No modelo de perfusÃo intestinal, a desnutriÃÃo aguda aumentou a secreÃÃo intestinal de eletrÃlitos e Ãgua. A TC aumentou a secreÃÃo de eletrÃlitos e Ãgua em modelo de perfusÃo intestinal de camundongos. A TC aumentou a transcriÃÃo para o RNAm dos transportadores intestinais SGTL-1, PEPT-1 e CAT-1, mas nÃo aumentou a transcriÃÃo para o SN-2. As soluÃÃes de reidrataÃÃo com glicose (SGli), glutamina (SGln), alanil-glutamina (SAla-Gln) e arginina (SArg) diminuÃram a secreÃÃo de eletrÃlitos induzida pela TC. Apenas a SGln nÃo conseguiu diminuir significativamente a secreÃÃo de Ãgua induzida pela TC. Apenas a SGli reduziu a secreÃÃo de Ãgua induzida pela TC. SGli, SAla-Gln e SArg, mas nÃo SGln, diminuÃram a secreÃÃo de sÃdio e cloreto induzida pela TC. A desnutriÃÃo associada à diarreia pela TC causou reduÃÃo na transcriÃÃo para o RNAm dos transportadores intestinais SGTL-1, PEPT-1, CAT-1 e SN-2. A desnutriÃÃo associada à TC aumentou a secreÃÃo de Ãgua quando comparado ao grupo nutrido exposto à TC. SGli, SAla-Gln e SArg, mas nÃo SGln, diminuÃram a secreÃÃo de Ãgua induzida pela desnutriÃÃo associada à TC. Todas as soluÃÃes diminuÃram a secreÃÃo de sÃdio e cloreto induzida pela desnutriÃÃo associada à TC. / The morbidity and mortality rates rise when diarrhea is associated with malnutrition. However, the mechanisms by which nutritional deficiencies affect the gut are largely unknown. The aim of this study was to evaluate morphological changes in transport proteins and substrates in intestinal transport of electrolytes and water in malnutrition model in mice. We aim to further analyze the effect of cholera toxin (CT) with or without malnutrition on the carrier proteins substrates on electrolyte transport in mice and finally, we evaluate the effects of oral rehydration solutions (ORS) of OMS (SGli) e modified with glutamine (SGln), alanyl-glutamine (SAla-Gln) and arginine (SArg) in this transport. Mice (n=20) received for 7 days a diet deficient in protein, fat and minerals (DBR). Segments of ileum were obtained before and on day 7 of the diet, for studies of morphology, immunohistochemistry for proteins: SGTL-1, PEPT-1, CAT-1 and SN-2 and evaluated by RT-qPCR of mRNA expression of these transport proteins. The model of intestinal perfusion for 75 min in mice (n=6) was used to evaluate the intestinal transport of water and electrolytes and to evaluate the role of oral rehydration solutions in mice exposed nourished and malnourished or without cholera toxin (1Âg/ml). Malnourished animals showed weight loss, atrophy of the villi and reduced expression by immunofluorescence of SGTL-1. Malnutrition also caused a reduction in mRNA expression SGTL-1 and PEPT-1 and increased mRNA expression for SN-2 in mice ileum. In the model of intestinal perfusion, acute malnutrition increased intestinal secretion of electrolytes and water. CT increased the secretion of electrolytes and water into the intestinal perfusion model mice. SGli, SGln, SAla-Gln and SArg decreased secretion of electrolytes induced by CT. Just SGln failed to significantly decrease water secretion induced by CT. CT increased mRNA transcription for intestinal transporters SGTL-1, PEPT-1 and CAT-1 but not to increased transcription SN -2. Only SGli reduced water secretion induced by CT. SGli, SAla-Gln and SArg, but not SGln , decreased secretion of sodium and chloride induced by CT. The malnutrition associated with diarrhea caused by TC reduction in the transcription of mRNA for intestinal transporters SGT -1, PEPT-1, CAT-1 and SN-2. Malnutrition associated with CT increased the secretion of water when compared to the group fed exposed to TC. SGli , SAla-Gln and SArg, but not SGln, decreased water secretion induced by malnutrition associated with TC. All solutions decreased secretion of sodium and chlorid induced malnutrition associated with TC.

Background: The cholera epidemic experienced in the province of KwaZulu-¬Natal between August 2000 and July 2001 resulted in 105, 000 reported cases of cholera and 220 human deaths. Objectives: The primary objective of this study was to make comparison between districts with cholera and districts with no cholera in rural KwaZulu-Natal on the basis of known risk factors for cholera and diarrhoeal diseases. Comparison was made with regards to key factors such as the prevalence of diarrhoeal diseases, the provision of safe water supply, ownership and effective utilization of sanitary facilities, knowledge and practice on water purification and prevention of cholera. Methods and materials: This was a descriptive, cross- sectional, ecological and comparative study among households of KwaZulu-Natal. The communities were stratified into two groups. One group had cholera (Group 1) and the other group (Group 2) had no cholera. Thirty communities were selected by systematic random selection from each of the two groups. From each community, eligible households were selected using simple random sampling technique. Trained field workers used a pre-tested questionnaire to collect data during the months of November and December 2001. Statistical procedures such as two-sample tests on means and proportions, Pearson's chi-square tests of association, odds ratios, binary logistic regression analysis, sensitivity tests, specificity tests and ROC (receiver of characteristics) analysis were used for data analysis. Results: A total of 1420 households from both groups were included in the study. The response rate for Group 1 and Group 2 was 84%,92%. Female respondents (70%) predominated male respondents (30%). Tap water supply was less common in Group 1 (54%) than in Group 2 (72%), (p< 0.05). A higher percentage of households in Group 1 (27%) used dam or river water compared to Group 2 (20%) (p<0.05). Household knowledge on water purification by boiling was (71%) in Group 1 and (87%) (p<0.05) in Group 2.38% of households in Group 1 practiced water purification by using disinfectant JIK. The corresponding figure for Group 2 was 50% (p<0.05). Groups 1 and 2 were similar with respect to ownership of toilets (84% and 85% respectively). Groups 1 and 2 showed a marked difference with respect to utilization of toilet facilities by all family members (70% and 89% respectively). The prevalence of diarrhoeal diseases for Group 1 was higher (14.3%) (p<0.05) than the Group 2 was (11.1%). Factors found to be helpful for protection against diarrhoeal diseases were the boiling of water (OR=0.41, 95% CI, 0.19-0.90) and the use of disinfectant JIK (OR=0.45, 95% CI, 0.19-0.94). The study also showed that the use of dam or river water was significantly associated with diarrhoeal diseases (OR=2.92, 95% CI, 1.06-7.80). Conclusion: The results showed that there was significant difference between the two groups of households in regards to basic provision of safe water, knowledge and practice of good hygiene, ownership and effective utilization of sanitary facilities. Findings from this study could be useful as baseline information for future planning, monitoring and evaluation of ongoing programmes. / Dissertation (MSc(Epidemiology))--University of Pretoria, 2005. / School of Health Systems and Public Health (SHSPH) / unrestricted

Thesis advisor: Thomas C. Chiles / Rapid diagnosis of infectious disease at the site of the patient is critical for preventing the escalation of an outbreak into an epidemic. This is particularly true for cholera, a disease known to spread swiftly within resource-limited populations. A device suited to point-of- care (POC) diagnosis of cholera must not only demonstrate laboratory levels of sensitivity and specificity, but it must do so in a highly portable, low-cost manner, with a simplistic readout. Here, we report novel proof-of-concept lab-on-a-chip (LOC) electrochemical immunosensors for the detection of cholera toxin subunit B (CTX), based on two nanostructured architectures: the gold dendritic array, and the extended core coax (ECC). The dendritic array has an ~18x greater surface area than a planar gold counterpart, per electrochemical measurements, allowing for a higher level of diagnostic sensitivity. An electrochemical enzyme-linked immunosorbant assay (ELISA) for CTX performed via differential pulse voltammetry (DPV) on the dendritic sensor demonstrated a limit-of detection of 1 ng/mL, per a signal-to-noise ratio of 2.6, which was more sensitive than a simple planar gold electrode (100 ng/mL). This sensitivity also matches a currently available diagnostic standard, the optical ELISA, but on a miniaturized platform with simple electrical readout. The ECC was optimized and explored, undergoing several changes in design to facilitate sensitive LOC electrochemical detection. The ECC matched the off-chip sensitivity towards CTX demonstrated by a previous non-extended core coaxial iteration, which was comparable to a standard optical ELISA. In contrast to the previous coaxial architecture, the ECC is amenable to functionalization of the gold core, allowing for LOC detection. ECCs were functionalized using a thiolated protein G, and CTX was detected via an electrochemical ELISA. While this work is ongoing, the ECC shows promise as a platform for LOC electrochemical ELISA. The ability to potentially meet POC demands makes biofunctionalized gold dendrites and ECCs promising architectures for further development as LOC sensors for the detection of infectious disease biomarkers. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.