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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.
41

Antibody responses and Fc gamma receptor IIa polymorphism in relation to Plasmodium falciparum malaria

Iriemenam, Nnaemeka C. January 2009 (has links)
Immunity to asexual blood-stage of Plasmodium falciparum malaria is believed to be associated with protective antibodies of certain immunoglobulin classes and subclasses. This thesis addressed the importance of antibodies in relation to malaria infection and their effective interactions with Fc gamma receptor IIa (FcyRIIa) polymorphisms. Our data indicate that the frequency of FcyRIIa-R/R131 genotype was statistically significantly higher in Sudanese patients with severe malaria, while the FcyRIIa-H/H131 genotype showed a significant association with mild malaria. The levels of IgG1 and IgG3 subclass antibodies were statistically higher in the mild malaria patients. The Fulani ethnic group in West Africa has been shown to be relatively resistant to malaria. We investigated the possible impact of FcyRIIa polymorphisms in the Fulani and non-Fulani in Mali and Sudan, and analysed their malaria-reactive IgG subclass profiles. The FcyRIIa-H/H131 genotype and H131-allele were found to be prevalent in the Fulani while R131-allele was prevalent in non-Fulani. The Fulani had higher serum levels of IgG1-3, with higher proportion of IgG2 than the non-Fulani. Most clinico-epidemiology studies have been in areas with holo- and hyper-malaria endemicity. We have analysed antibody responses to a panel of six blood-stage antigens in relation to clinical malaria outcome in mesoendemic Sudan. Our results revealed a linear association with anti-AMA-1 IgG1 antibodies and reduced risk of severe malaria while a non-linear relationship with IgG3 antibodies was observed for MSP-2, MSP-3 and GLURP. In the combined final model, the highest levels of IgG1 subclass antibodies to AMA-1, GLURP-R0, and the highest levels of IgG3 subclass antibodies reactive to 3D7 MSP-2 were independently associated with a reduced risk of clinical malaria. Taken together, these data suggest a possible association between FcyRIIa-R/H131 and anti-malarial antibody responses in the clinical outcome of malaria.
42

Assessing ecological correlates of avian disease prevalence in the Galápagos Islands using GIS and remote sensing

Siers, Shane R. January 1900 (has links)
Title from title page of PDF (University of Missouri--St. Louis, viewed March 9, 2010). Includes bibliographical references.
43

Annexins A1 and A2 as potential biomarkers of stress and respiratory disease susceptibility

Senthilkumaran, Chandrika 28 August 2013 (has links)
This study investigated proteomic changes in bronchoalveolar lavage fluid (BALF) of beef calves to identify alterations related to development of naturally occurring bovine respiratory disease. BALF was collected from 162 healthy beef calves soon after weaning and transportation. Two-dimensional gel electrophoresis and mass spectrometric analysis revealed calves that later developed pneumonia had significantly lower levels of anti-inflammatory proteins including annexin A1, RAGE-binding protein, apolipoprotein-A, heat shock protein beta-1 and thioredoxin, but higher levels of antioxidant and pro-inflammatory proteins such as immunoglobulin light chain variable region, cyclophilin A, serum albumin precursor and glutathione S-transferase P. Difference in gel electrophoresis-based analysis further showed lower levels of annexin A1, annexin A2, peroxiredoxin I, calycyphosin, superoxide dismutase, macrophage capping protein and dihydrodiol dehydrogenase 3 in the calves that later developed pneumonia. Differences in annexin levels were partially confirmed by Western blot analysis. In healthy calves, immunohistochemistry revealed cytoplasmic expression of annexin A1 in surface epithelium of large airways, tracheobronchial submucosal glands, and goblet cells, and to a lesser degree in small airways but not in alveolar epithelium. Flow cytometry and immunocytochemistry labeled annexin A1 in blood and bronchoalveolar lavage neutrophils, monocytes, macrophages and lymphocytes. Annexin A2 expression was detected in surface epithelium of small airways, some mucosal lymphocytes, and endothelium, with weak expression in large airways, tracheobronchial submucosal glands and alveolar epithelium. For both proteins, the level of expression was similar in tissues collected 5 days after intrabronchial challenge with M. haemolytica compared to that from sham-inoculated calves. A sandwich ELISA for annexin A1 was developed. For use with BALF, the working range was 0.3-317 ng/ml and the sensitivity was 0.8 ng/ml. The coefficient of variation of intra-assay and the between assays was less than 20%. Together, these findings reveal annexins A1 and A2 as promising biomarkers of susceptibility to BRD in healthy at-risk calves. Further, the anti-inflammatory and pro-resolving functions of these proteins suggest roles in the pathogenesis of bacterial pneumonia of feedlot cattle. / Natural Sciences and Engineering Council (NSERC), Ontario Cattlemen’s Association, Ontario Ministry of Agriculture and Food and Ontario Veterinary College Fellowship Program
44

Breed susceptibility to enterotoxigenic and enteroaggragative Escherichia coli strains in South African pigs.

Chaora, Nyaradzo Stella. January 2013 (has links)
Escherichia coli diarrhoea is the most important source of mortality in piglets. The most frequently isolated strain in enterotoxigenic E. coli diarrhoea is F4ab/ac. Recent studies in South Africa reported non-fimbrial strains such as PAA and EAST-1 to be prevalent. The objective of the study was to determine whether there are breed differences among pigs with respect to E. coli adhesion phenotypes and correlate them to polymorphisms at selected candidate genes in the South African population. A total of 225 pigs aged 3-12 weeks of the imported (Large White, Landrace and Duroc), local and crossbreds, were sampled from the Eastern Cape and Limpopo provinces of South Africa and genotyped for PCR-RFLP polymorphisms at four candidate genes associated with E. coli F4ab/ac resistance/susceptibility. These genes were Mucin 4 (MUC4), Mucin 13, (MUC13), Mucin 20 (MUC20) and Transferrin Receptor (TFRC). The TFRC and MUC13 genes were less polymorphic, the C allele was close to fixation and the homozygous CC genotype was the most frequent in all three pig populations. There was a significant difference (P <0.05) in allelic and genotypic distribution amongst breeds for the TFRC locus. The g.8227G>C polymorphism in MUC4 segregated in all three breeds and the marker was moderately polymorphic. There was a significant difference (P <0.05) in genotypic distribution amongst breeds for MUC4.The g.191C>T polymorphism in MUC20 segregated in the local and crossbred pigs and was close to fixation in the imported pigs. There was a significant difference (P <0.05) in allelic and genotypic distribution amongst breeds for MUC20, which was moderately polymorphic. There was a reduction in heterozygosity in both the TFRC and MUC13 loci, although MUC4 and MUC20 genes had higher heterozygosity levels. The MUC4 gene had a negative FIS value, indicating outbreeding at this locus. The MUC20, MUC13 and TFRC genes had a positive FIS value, indicating inbreeding at these loci. Overall, the studied population was outbred. Imported pigs in TFRC and MUC20 deviated from Hardy-Weinberg equilibrium (HWE). All breeds were in HWE at the MUC4 and MUC13 genes. There was no linkage disequilibrium observed amongst the analysed loci. iv A total of 109 piglets of three breeds (Large White, indigenous and crossbred) aged 3-5 weeks, were investigated for the susceptibility to E. coli F4, PAA strains and EAST-1 toxin. Adhesion tests were conducted on pig intestinal cells, which were viewed under a phase contrast microscope. Three phenotypes were identified as, adhesive, weakly adhesive and non-adhesive. There was a significant association (P <0.05) between breed and level of adherence of the F4 and PAA strains. Highest frequencies of adhesion phenotypes were observed in the indigenous pigs for both F4 and PAA E. coli strains. Large White pigs had the lowest frequency of non-adhesion in F4 and PAA E. coli strains. The F4 strain had a higher (P <0.05) level of adherence compared to PAA and EAST-1 in Large White pigs. Age of pigs had a significant effect on the level of E. coli adherence in indigenous and crossbred pigs (P <0.05). Adhesion of F4 and EAST-1 was higher in weaned indigenous and crossbred pigs, respectively, than in suckling piglets. There was no significant difference between F4 adhesion and the genotypes at all four candidate genes genotypes. The study showed that both imported and local pig populations carry receptors and are susceptible to F4, PAA and EAST-1 E. coli infections. Indigenous pigs were less susceptible than Large White to E. coli infection. Although polymorphic and segregating in the populations, the MUC4 g.8227G>C and MUC20 g.191C>T mutations were not associated with the adhesion phenotypes and cannot be used in the selection of susceptible animals. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.
45

Avaliação antropométrica, prostatica e polimorfismos de TP53 e GSTP1 em populações do estremo setentrional amazônico / Antropometric, prostatic characteristics and single nucleotide polymorphisms of TP53 and GSTP1 in populatins of northern Brazil

Lima Junior, Mario Maciel de, 1974- 12 March 2012 (has links)
Orientadores: Laura Sterian Ward, Ubirajara Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T18:25:14Z (GMT). No. of bitstreams: 1 LimaJunior_MarioMacielde_D.pdf: 2397268 bytes, checksum: 63d55e4a5572d5d7f06e615be4d98384 (MD5) Previous issue date: 2012 / Resumo: As doenças da glândula prostática em geral e a incidência de câncer da próstata, em particular, mostram disparidades acentuadas entre os diferentes países e etnias. De fato, etnia, idade e história familiar são os mais fortes fatores de risco conhecidos para o câncer da próstata, mas a dieta, índice de massa corporal e outros fatores também podem influenciar o seu desenvolvimento. O objetivo deste estudo é descrever aspectos clínicos, antropométricos e genéticos da próstata de índios brasileiros da região amazônica. Foram analisados um total de 228 indígenas do sexo masculino ? 40 anos submetidos a exame físico, incluindo exame retal digital da próstata (TR), e a um questionário individualizado que incluía características demográficas e estilo de vida; história médica familiar e pessoal para câncer da próstata. Amostras de sangue foram obtidas para a determinação do antígeno prostático específico (PSA) e concentrações de testosterona sérica e genotipagem para TP53 e GSTP1. Os dados da população indígena foram comparados com os de um grupo controle de 87 não-indígenas masculinos da mesma região. Entre os 14 grupos étnicos identificados, Macuxi, é a etnia de índios aculturados mais frequente (43,6%), seguido pela Yanomami (14,5%), que é composta por índios mais isolados e primitivos. Os participantes tinham média de idade de 54,7 anos; circunferência abdominal de 86,6 cm e IMC de 23,9 kg/m2, com Yanomanis apresentando ambos IMC (21,4 contra 24,8; p=0,001) e peso da próstata mais baixos do que os Macuxis (15g contra 20g; p=0,001). Na população controle a idade média foi de 41 anos. Nenhum dos índios apresentaram sintomas relacionados à próstata e apenas um paciente teve diagnóstico de hiperplasia benigna da próstata, associada à manifestação de retenção urinária. Não foram identificadas diferenças nos valores de PSA (0,48 ng/mL contra 0,6 ng/mL; p=0,349) entre Yanomami e Macuxis. Observou-se correlação entre o IMC, peso da próstata, estilo de vida e hábitos alimentares, apesar das concentrações de testosterona (414 contra 502; p=0,207) serem semelhantes entre Macuxis e Yanomanis e, um aumento progressivo das concentrações de PSA ser observado com o envelhecimento em ambas etnias. A genotipagem de TP53 nos indígenas mostrou uma super representação do haplótipo selvagem Arg/Arg (74,5% versus 42,5%; p<0.0001) em relação à população controle. O perfil genotipico de GSTP1 também diferiu consideravelmente entre os não índios e os índios (Ile/Ile 60,9% versus 35,3%; Ile/Val 28,7% versus 45,9%; Val/Val 10,3% versus 18,8%; p = 0,0003, respectivamente). Não encontramos qualquer associação entre os hábitos alimentares ou características do estilo de vida, peso da próstata, PSA, concentrações de testosterona e o perfil genético da população investigada. No entanto, observamos especificidades alimentares, sociais e culturais nas populações estudadas, bem como um perfil genético específico para TP53 e GSTP1 que podem estar associados à boa saúde prostática da população indígena estudada / Abstract: Prostate diseases in general and prostate cancer incidence, in particular, show marked disparities among different countries and ethnicities. Age, ethnicity and family history are the strongest known risk factors for prostate cancer, but diet, body mass index and other factors may also influence its development. We aimed to describe clinical, anthropometric, genetic and prostatic features of Brazilian Indians from the Amazon area. A total of 228 male Indians ?40 years old were submitted to a physical examination, including digital rectal examination (DRE), and to an in-person questionnaire on demographic characteristics and life style; personal and familial medical history. Blood samples were obtained for the determination of total prostatic specific antigen (PSA) and serum testosterone levels. In addition, we obtained a control group of non-Indian males from the same region. Among the 14 ethnic groups identified, Macuxi group, composed by more acultured indians, was the most frequent (43.6%), followed by Yanomami (14.5%) group, that is composed by more isolated and primitive indians. Participants had a mean age of 54.7 years; waist circumference of 86.6 cm and BMI of 23.9 kg/m2, with Yanomamis presenting both lower BMI (21,4 versus 24,8; p=0,001) and lower prostate volume than Macuxis (15 versus 20; p=0,001). None of the indians presented prostate symptoms and only one patient had a benign prostate hyperplasia that caused urine retention. Serum PSA (0,48 versus 0,6 p=0,349). We observed a relationship among BMI, prostate volume, life style and dietary patterns, although testosterone (414 versus 502; p=0,207) levels were similar in Macuxi and Yanomami indians and a progressive increase of PSA levels was observed with aging in both groups. TP53 genotyping evidenced a different profile in indians, with a super representation of the Arg/Arg haplotype (74,5% versus 42,5%; p<0,0001) compared to the control population. Likewise, GSTP1 genotyping demonstrated very differently among control population compared to indians Ile/Ile 60,9% versus 35,3%; Ile/Val 28,7% versus 45,9%; Val/Val 10,3% versus 18,8%; p = 0,0003); respectively. We were not able to find any association among dietary patterns or any life style characteristic; prostate volume, serum PSA and testosterone levels; and the genetic profile of the investigated population. We observed specific dietary, social and cultural features, as well as a specific genetic profile for TP53 and GSTP1 that may contribute to Brazilian Indian population prostate good health / Doutorado / Clinica Medica / Doutor em Clínica Médica
46

Modeling cancer predisposition: Profiling Li-Fraumeni syndrome patient-derived cell lines using bioinformatics and three-dimensional culture models

Phatak, Amruta Rajendra 07 October 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Although rare, classification of over 200 hereditary cancer susceptibility syndromes accounting for ~5-10% of cancer incidence has enabled the discovery and understanding of cancer predisposition genes that are also frequently mutated in sporadic cancers. The need to prevent or delay invasive cancer can partly be addressed by characterization of cells derived from healthy individuals predisposed to cancer due to inherited "single-hits" in genes in order to develop patient-derived samples as preclinical models for mechanistic in vitro studies. Here, we present microarray-based transcriptome profiling of Li-Fraumeni syndrome (LFS) patient-derived unaffected breast epithelial cells and their phenotypic characterization as in vitro three-dimensional (3D) models to test pharmacological agents. In this study, the epithelial cells derived from the unaffected breast tissue of a LFS patient were cultured and progressed from non-neoplastic to a malignant stage by successive immortalization and transformation steps followed by growth in athymic mice. These cell lines exhibited distinct transcriptomic profiles and were readily distinguishable based upon their gene expression patterns, growth characteristics in monolayer and in vitro 3D cultures. Transcriptional changes in the epithelial-to-mesenchymal transition gene signature contributed to the unique phenotypes observed in 3D culture for each cell line of the progression series; the fully transformed LFS cells exhibited invasive processes in 3D culture with disorganized morphologies due to cell-cell miscommunication, as seen in breast cancer. Bioinformatics analysis of the deregulated genes and pathways showed inherent differences between these cell lines and targets for pharmacological agents. After treatment with small molecule APR-246 that restores normal function to mutant p53, we observed that the neoplastic LFS cells had reduced malignant invasive structure formation from 73% to 9%, as well as an observance of an increase in formation of well-organized structures in 3D culture (from 27% to 91%) by stereomicroscopy and confocal microscopy. Therefore, the use of well-characterized and physiologically relevant preclinical models in conjunction with transcriptomic profiling of high-risk patient derived samples as a renewable laboratory resource can potentially guide the development of safer and more effective chemopreventive approaches.
47

Psychosocial factors and susceptibility to the common cold in distance runners

Struwig, Gillian Anne 30 November 2004 (has links)
This study investigated the relationship between specific psychosocial factors and susceptibility to the common cold in a sample of 124 distance runners. A cross-sectional survey design was used to assess the role of life events, coping, hardiness, training workload and competition frequency in the athlete's risk of infection. Using correlational statistical techniques, it was found that the magnitude of recent life changes and the avoidance coping strategy of denial were positively related to self-reported symptoms of the common cold. Furthermore, a significant inverse correlation was observed between hardiness and symptom duration scores. However, approach coping, training workload and competition frequency were not significantly related to the dependent measures. The results of this study suggest that certain stress-related psychosocial factors are associated with susceptibility to the common cold in distance runners. Several strategies for the prevention and treatment of upper respiratory tract infections in this group are implied by these findings. / Psychology / M.A. (Psychology)
48

Psychosocial factors and susceptibility to the common cold in distance runners

Struwig, Gillian Anne 30 November 2004 (has links)
This study investigated the relationship between specific psychosocial factors and susceptibility to the common cold in a sample of 124 distance runners. A cross-sectional survey design was used to assess the role of life events, coping, hardiness, training workload and competition frequency in the athlete's risk of infection. Using correlational statistical techniques, it was found that the magnitude of recent life changes and the avoidance coping strategy of denial were positively related to self-reported symptoms of the common cold. Furthermore, a significant inverse correlation was observed between hardiness and symptom duration scores. However, approach coping, training workload and competition frequency were not significantly related to the dependent measures. The results of this study suggest that certain stress-related psychosocial factors are associated with susceptibility to the common cold in distance runners. Several strategies for the prevention and treatment of upper respiratory tract infections in this group are implied by these findings. / Psychology / M.A. (Psychology)
49

Innate Immune Memory and the Host Response to Infection

Sherwood, Edward R., Burelbach, Katherine R., McBride, Margaret A., Stothers, Cody L., Owen, Allison M., Hernandez, Antonio, Patil, Naeem K., Williams, David L., Bohannon, Julia K. 15 February 2022 (has links)
Unlike the adaptive immune system, the innate immune system has classically been characterized as being devoid of memory functions. However, recent research shows that innate myeloid and lymphoid cells have the ability to retain memory of prior pathogen exposure and become primed to elicit a robust, broad-spectrum response to subsequent infection. This phenomenon has been termed innate immune memory or trained immunity. Innate immune memory is induced via activation of pattern recognition receptors and the actions of cytokines on hematopoietic progenitors and stem cells in bone marrow and innate leukocytes in the periphery. The trained phenotype is induced and sustained via epigenetic modifications that reprogram transcriptional patterns and metabolism. These modifications augment antimicrobial functions, such as leukocyte expansion, chemotaxis, phagocytosis, and microbial killing, to facilitate an augmented host response to infection. Alternatively, innate immune memory may contribute to the pathogenesis of chronic diseases, such as atherosclerosis and Alzheimer's disease.

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