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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.
281

The Genetics of Cardiovascular Risk Factor Correlations

Kodaman, Nuri 08 December 2015 (has links)
Cardiovascular disease (CVD) is the leading cause of death worldwide. The vast possibilities of interaction between genetic and environmental factors that contribute to CVD can be simplified by identifying conditions that favor the emergence of specific risk factor networks. If the relationships among CVD risk factors that give rise to these networks are under genetic control, then such relationships can be considered heritable phenotypes in themselves, amenable to genetic analysis. We characterized correlational networks of cardiovascular risk factors in a large cohort of urban and rural men and women in Ghana, and investigated how they may be perturbed by factors such as sex and urban lifestyle. We also assessed the comparative relevance of individual risk factors to thrombosis within and across networks, using as a proxy their association with an intermediate phenotype of CVD, plasminogen activator inhibitor type-1 (PAI-1). We found that the relationships between risk factors and PAI-1 were far more sensitive to differences in sex and environment than were the relationships among the risk factors themselves. <p> To lay the theoretical groundwork for our subsequent genetic analyses, we modeled multiple types of biological SNP-by-covariate interactions and derived the statistical parameters to which they should give rise. In doing so, we demonstrated that even the strongest gene-by-covariate interactions at the biological level could display weak statistical interactions using general linear models. Moreover, we quantified the expected strength of the interaction relative to the marginal effect, depending on the nature of biological interaction. We then developed the ordinal joint interaction model (OJIM), which can not only identify biological SNP-by-covariate interactions where they exist, but also pick up marginal effects and leverage the change in residual correlation induced by marginal effects. In our analyses of the Ghanaian study population, the OJIM had more power than univariate or bivariate analysis to detect lipid SNPs of known biological significance, indicating that context-dependent genetic effects are probably quite common, and that the OJIM can identify them where they exist. We also used the OJIM to interrogate exome-wide data of our Ghanaian study population, and identified genetic variants that may increase thrombotic risk by influencing the covariance between these risk factors and PAI-1.
282

Maternal Mortality in Guatemala from a Human Rights Perspective

Belfrage, Amanda January 2015 (has links)
No description available.
283

Sister chromatid exchange rates in human twins

Zukowski, Mark M. January 1978 (has links)
No description available.
284

Chromosome abnormalities in preimplantation bovine embryos

Ben Amor, Hanene January 2004 (has links)
Note: / Studies suggest that chromosomal abnormalities notably mosaicism consisting of normal and abnormal cells is a common feature observed in mammalian preimplantation embryos. The data on chromosome abnormalities in bovine embryos however, are limited. The principal aim of this study was to investigate chromosome abnormalities and their effect on the development of bovine embryos produced in vitro. 193 embryos were evaluated for chromosomal abnormalities, using dual fluorescent in situ hybridization (FISH) with developed DNA probes for X and Y chromosomes. Our results demonstrate that uniformly abnormal embryos were found mostly at the early cleavage stages, and embryos with extensive chromosome abnormalities were usually arrested by the morula stage. Chromosomal mosaicism was observed at the 2- cell stage and increased steadily with subsequent stages of development. By the blastocyst stage, chromosomal mosaicism was the main abnormality observed and affected 95% of the blastocysts. Most of the mosaic blastocysts comprised of diploid and tetraploid cells. In the second part, a detailed analysis of 121 day 7 and days 9-10 blastocysts, demonstrated that the proportion of polyploid cells in most of the morphologically good quality embryos was less than 15%, which was significantly lower than in poor quality embryos. [...] / II a ete suggere que des anomalies chromosomiques particulierement le mosaicism sont frequemment rencontres chez les embryons des bovins produit in vitro, cependant les donnees disponibles sont tres limitees. Le but principal de cette etude est d'evaluer les anomalies chromosomiques particulierement le mosaicism au different stades de developpement embryonnaire par FISH en utilisant des probes 'ADN pour les chromosomes X et Y. Nos resultats demontrent que des embryons uniformement anormales ont ete surtout trouves aux premiers stades de cleavage, temoignant que les embryons avec une vaste anomalie affectant la totalite des embryons sont souvent arretes au stade du morula. Le mosaicism chromosomique a ete rencontre dans tous les stades de developpement et il a augmente emarquablement pendant le developpement embryonnaire. Ainsi, au stade du blastocyst, le mosaicism chromosomique etait l'anomalie principale observee avec 95 % de blastocysts analyses devenant mosaiques. [...]
285

Validation of the Remote Food Photography Method to Quantify Intake of Infant Formula

Duhe, Abby 21 November 2013 (has links)
Childhood obesity rates have more than tripled since the 1970s, and this increased prevalence is cause for concern as childhood obesity increases the risk of adult obesity and other comorbid diseases. Evidence suggests that the origins of obesity can be identified in infanthood. Accurate methods of assessing food intake in infants can be utilized to establish effective feeding practices in infanthood and to assess the relationship between infant feeding practices and the risk of childhood obesity. Current methods are either subjective or have limited ability for widespread use beyond clinical research settings due to cost and high burden. The aim of the Baby Bottle study was to assess the accuracy of the Remote Food Photography Method (RFPM), a novel food intake assessment method, in estimating infant formula as compared to the gold standard, the directly weighed foods method. In the Baby Bottle study, fifty-three adults were recruited to prepare infant formula bottles and use the RFPM to capture photographs of infant formula at different stages of bottle preparation. Dry food provision, liquid food provision, and liquid waste gram weights measured by the RFPM and directly weighed foods method were compared to assess the accuracy of the RFPM in the estimation of infant formula. Paired dependent t-tests and the Bland-Altman regression method were employed to determine if the weight estimations of RFPM differed from the weights measured by the directly weighed foods method. Multivariate analysis of variance was used to analyze the effects of trial number and caregiver status on infant formula preparation. The RFPM estimated liquid formula intake within 10% of the directly weighed foods method, with error of -4.1 ± 14.4% (P<0.0001), 2.8 ± 16.3% (P=0.1550), and 7.0 ± 12.4% (P<0.0001) in 2 fluid ounce, 4 fluid ounce, and 6 fluid ounce bottles, respectively. The RFPM overestimated liquid formula intake by 14.0 ± 10.3% (P<0.0001) in 8 fluid ounce bottles. There were no significant differences between individuals in the caregiver group (n=28) and the non-caregiver group (n=25) based on all demographic and descriptive characteristics. There were no significant differences for the effects of trial number and caregiver status on infant formula preparation except for a significant main effect of caregiver status on the preparation of dry food provision of 2 fluid ounce bottles (P=0.0499) and a significant interaction between trial number and caregiver status on preparation of dry food provision of 4 fluid ounce bottles (P=0.0146). In conclusion, the RFPM is a viable method of measuring infant formula intake as it provides more valid estimates as compared to commonly used self-report methods in clinical practice and research and decreased cost, burden, and time commitment from individuals as compared to current objective methods.
286

IDENTIFYING BIOLOGICAL PATHWAYS IMPLICATED IN DEFINED SUBGROUPS OF PHENOTYPIC EXPRESSION FOR AUTISM SPECTRUM DISORDERS & EVALUATING SMALL MOLECULE EFFECTS ON EXPRESSION OF ASMT

Veatch, Olivia Jean 15 December 2013 (has links)
Autism Spectrum Disorder is a neurodevelopmental condition with evidence for genetic susceptibility. However, effect sizes for implicated loci are small, and current evidence does not explain the heritability. Phenotypic heterogeneity could be complicating genetic factor identification. We used multiple sources of behavioral and physiological data to identify ASD subgroups. Principal Components Analysis refined these data from an ASD dataset into 15 components best explaining phenotypic variance. Clustering identified two distinct groups, primarily based on phenotype severity. Using an independent dataset, we identified 15 data components and confirmed the severity-based dichotomy. There is significant familial clustering within groups, suggesting the clusters recapitulate genetic etiology. We performed separate family-based analyses of genetic data based on subgroup. Pathway analysis was performed. Five biological pathways uniquely associate with the less severe subgroup. Ten genes potentially drive these associations. Five different pathways uniquely associate with the more severe subgroup. 24 genes potentially drive associations with this subgroup. There is minimal overlap when comparing genes associated with different subgroups. We validated results in an independent dataset and see unique biological mechanisms associate with the more severe and less severe subgroups. Our results suggest meaningful subgroup definitions can help clarify the genetics of ASD. Uncovering pathways associated with subgroups further elucidated potential genes involved in trait expression. To progress toward understanding how these findings could be useful for treatment, functional characterization was necessary. Ample evidence indicates many drugs have altered efficacy and side effects in relation to genetic background. For many compounds used to treat ASD comorbid symptoms, individuals exhibit sleep problems. We evaluated the enzyme catalyzing the final reaction in melatonin synthesis, Acetylserotonin O-methyltransferase. We screened cell lines generated from patient DNA for differential expression effects against compounds presently used to treat symptoms. We replicated previous findings indicating homozygous presence of ASD risk alleles at promoter SNPs results in decreased gene expression. We also observe previously unreported expression effects attributable to heterozygosity at promoter SNPs, and a SNP in the 5'-UTR. Results show no significant changes in gene expression upon exposure to small molecule compounds for the non-risk haplotype.
287

Female Collegiate Volleyball Athletes' Perceptions of Identity, specific to Sport and Gender, as Understood by Their In-sport and Everyday Dress and Appearance Practices

Pattison, Jessica Ann 17 December 2013 (has links)
The purpose of this qualitative study was to explore how female collegiate volleyball athletes use dress and appearance practices to create, maintain, and negotiate their sport identity and gender identity, in-sport and everyday, from the time they played collegiate volleyball to present day. The study was guided by grounded theory and phenomenology. Semi-structured, in-depth, active qualitative interviews with 12 women, who represented American, Brazilian, Canadian, and Romanian viewpoints, were analyzed using open coding and thematic analysis procedures. Analysis revealed three key themes related to female collegiate volleyball athletes use of dress and appearance practices as a means to shape and influence their sport and gender identities: (a) conceptualizing the female collegiate volleyball culture as understood by dress and appearance, (b) female collegiate volleyball athlete subject formation, and (c) performing female collegiate volleyball athlete identities. Findings revealed that they used dress and appearance practices to understand their sport identity and gender identity when they played volleyball in college and that they currently use dress and appearance practices in their everyday lives as a way to understand their subject positions. Female collegiate volleyball athletes conceptualized their ways of understanding social and cultural expectations by using their dress and appearance practices and bodies as mediums for interpretation.
288

Cloning of Human Coronavirus NL-63 ORF3, M and E genes for antibody production

Fisher, Randall Graeme January 2010 (has links)
<p>Human Coronavirus NL-63 is a respiratory virus with a high incidence rate, causing mild respiratory infections in children under the age of 18. The outbreak of Sever Acute Respiratory&nbsp / Syndrome (SARS) in 2003 sparked increased interest into the field of coronavirology and respiratory diseases subsequently led to the discovery of this novel Human Coronavirus (HCoV) by a group of scientists in Holland. The membrane protein (M) of NL-63 has been shown to interact with the nucleocapsid, spike and envelope proteins of the virus when expressed ex vivo. In contrast, the envelope protein (E) is shown to exhibit ion channel activity, interacts with the membrane protein during the formation of viral-like particles. The functions of the open reading frame 3 (ORF3) proteins remains a mystery. Research does, however, indicate that this protein is needed for in vivo infectivity and pathogenesis. Bioinformatic analysis indicates that both the ORF3 and M proteins posses at least 3&rsquo / C-terminal transmembrane regions. To further characterize the biological activity of these three proteins in clinical and laboratory samples, sensitive and specific antibodies are required. Thus, the antigenic regions of ORF3, M and the entire E gene were amplified by PCR and ligated into a bacterial expression vector for expression and subsequent generation of antibodies in a mouse system. The identities of the cloned genes were confirmed by sequencing before being expressed in an in vitro bacterial system. Western Blots were used to identify the expression of the 41kDa, 42kDa and 34kDa GST-tagged viral proteins which were consistent with the bioinformatically predicted protein species. Verified fusion proteins were expressed in large quantities, quantified and concentrated for in vivo antibody production. Inoculation of 9 healthy, female Balb/C mice with the purified fusion proteins yielded high titers of polyclonal antibodies. Western Blotting was once again used to validate the production of the antibodies before their specificity was quantitatively measured using a modified competition ELISA.</p>
289

FLUORESCENCE IN SITU HYBRIDIZATION AS A DIAGNOSTIC TOOL FOR THE DETECTION OF THE FANCA delE12-31 AND delE11-17 MUTATIONS

Nogabe, Sibongile Joy 12 September 2007 (has links)
Fanconi anaemia (FA) is a rare autosomal recessive and X-linked disorder characterized by a very high frequency of bone marrow failure and many other manifestations. These include, but are not restricted to, severe birth defects and marked predisposition to malignancies, especially acute myeloid leukaemia and, to a lesser extent, solid tumours (Rodriguez et al, 2005). Cells from FA patients are hypersensitive to agents that produce DNA cross-links, and after in vitro treatment with these agents, display marked chromosome breakage and other cytogenetic abnormalities. FA shows genetic heterogeneity with mutations in any of twelve genes resulting in a similar phenotype. Current diagnostic criteria for FA relies mainly on cytogenetic quantification of chromosomal breakage in response to DEB and/or MMC. The diagnostic value of induced chromosome instability does not appear to be feasible for differentiating between FA carriers and non-carriers, since overlapping in quantitative values between the two groups is common place. In this investigation a population based screening strategy was followed. The method based on fluorescent in situ hybridization (FISH) was applied to allow a rapid and unequivocal identification of two founder Afrikaner FAA gene deletions, in both homozygous and carrier states. Direct labeling by both nick translation and thermal cycling amplification, using dUTP-labeled fluorochromes, resulted in no visible signals after hybridization, even though labeling proved to be successful. This restriction may be ascribed to the relatively small size (1.8kb and 2.3kb, respectively) of the DNA probes. Efficiency of hybridization detection decreases with decreasing probe size and a more sensitive detection method may solve this problem. Indirect labeling by polymerase chain reaction (PCR) amplification using digoxigenin-dUTP (DIG-dUTP) and antibodies (anti-DIG fluorochromes), provides an extremely sensitive method of detection, albeit more time consuming and costly. Bright, clearly defined signals were visualized after hybridization, using fluorescent microscopy. Stringent hybridization conditions, such as formamide contents of the hybridization buffer (70%) and optimal probe concentration (150ng), enhanced target-specificity and reduced background interference to almost none. Predominantly (>70% of interphase nuclei) the number of signals were in agreement with the ploidy of the specific DNA sequence, but the remaining cells revealed a mixture of either one, two or three signals. Target specificity tends to be a problem, especially with the smaller probe. Probes that are too small tend to bind non-specifically and re-hybridize, leaving smaller amounts of probe available for hybridization to the specific target. Even though, after hybridization, both probes resulted in easily visible fluorescent signals, the smaller delE11-17 probe (1.8kb) tended to be more prone to background interference with the signal, and, in addition, less target-specific. Probe hybridization efficiency and background are both influenced by the size of the labeled probe. The length of the probe molecule is critical for probe diffusion and hybridization to the specific target sequence. Probe size should be improved in order to provide a reliable and unequivocal diagnostic tool in the diagnosis of both FA patients and carriers. Longer probes will improve target-specificity and reduce the possibility of hybridization to other complementary regions in the genome. In conclusion, making use of this unique application of FISH offers an effective population directed screening for FA carriers and affected.
290

IMPACT OF A DIET INTERVENTION PROGRAM ON THE SERUM ALBUMIN CONCENTRATIONS, ANTROPOMETRICAL STATUS AND QUALITY OF LIFE OF BREAST CANCER PATIENTS RECEIVING CHEMOTHERAPY

Smalberger, René 25 September 2007 (has links)
Breast cancer patients receiving chemotherapy at ECOC, often present with lowered serum albumin concentrations, so much so that the lowered serum albumin concentrations first has to be treated before the next cycle of chemotherapy can be administered. The delay in chemotherapy treatment had financial, medical and emotional effects on the patients. The objective of this study was to determine the effect of an optimal energy increased protein (OEIP) dietary treatment on serum albumin concentrations, anthropometrical status and quality of life of breast cancer patients receiving chemotherapy. In a clinical trial, 27 female breast cancer patients were randomised to an experimental group (E) (n=13), receiving an individualized OEIP diet consisting of food and a nutritional supplement, or a control group (C) (n=14), receiving no dietary intervention. Baseline and three-weekly visits involved determining serum albumin concentrations; anthropometrical assessment, including body weight; BMI, MUAC, TSF, MAFA, MAMA, BF% and LM%; and the completion of a quality of life questionnaire. Both groups kept a food diary for the duration of the study. Median ages of the E-and C-groups were 52.62 and 51.19 years respectively, ranging from 29 to 59 years. Statistical analysis included, median and percentiles for continuous data, and frequencies and percentages for categorical data, with 95% CI for median differences. Due to the small sample size, nonparametric statistics were used to compare results. By taking a daily nutritional supplement, the E-group was able to consume a significantly better amount of all macro- and micronutrients. The C-group showed a median drop of 3 g/dL in serum albumin concentrations with a median end value of 36.5 g/dL, while the E-group showed a statistically significant [2; 6] median increase of 1.5 g/dL, with a median end value of 39 g/dL, suggesting that the dietary intervention had been successful in improving serum albumin concentrations over the treatment period. No statistically significant changes were noted in either the E- or C- groupâs performance status scoring. The Rotterdam Quality of Life Survey found the Egroup had a significant improved quality of life scoring during Visits 5:B, compared to the C-group for the same period. Other studies have also shown an improvement in quality of life measurement after the implementation of a dietary intervention programme in cancer patients. An optimal energy diet, sufficient to maintain the patientâs ideal body weight and not actual body weight, with a protein intake of 1.04 g/kg/day was sufficient to significantly improve serum albumin concentrations, to such an extent, that chemotherapy cycles did not have to be postponed. Regardless of nutritional intake, no statistically significant changes were found in weight, BMI, MUAC, TSF, MAFA or MAMA. The E-group showed a significant increase in BF% and a decrease in LM% for the duration of the study, compared to the C-group. The increase in BF% could possibly be explained by the high-energy, increased fat intake of the E-group. Changes in protein metabolism and the increased protein needs of the body could possibly explain the changes in LM%. From this study it may be concluded that an OEIP diet is not effective in preventing LM wasting. An OEIP (1-1.5 g/kg/day) dietary intervention, is therefore recommended for breast cancer patients receiving chemotherapy. Nutritional intervention should commence at an earlier point to determine the effect of such intervention on patientsâ quality of life. It is recommended that the study be repeated with a larger sample size, to confirm tendencies found in the present study and to determine the long-term effect of an OEIP diet intervention on serum albumin concentrations, the anthropometrical status, and the quality of life of breast cancer patients receiving chemotherapy.

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