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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

The Genetics of Insulin Resistance: Analysis of the Peroxisome Proliferator-Activated Receptor Pathway

Boudreaux, Monique Yvonne 09 June 2005 (has links)
Polycystic ovary syndrome (PCOS) is a heterogeneous familial disorder characterized by insulin resistance and an increased risk of type 2 diabetes mellitus (T2DM), a disorder with epidemic public health significance. The aim of this dissertation was to determine the risk of T2DM among Caucasian and African American women with PCOS compared to controls and to assess potential genetic variants that may affect development of T2DM. T2DM was defined as a fasting plasma glucose level >=126 mg/dL or self-report of physician diagnosis. Genetic variants analyzed for association with PCOS and subclinical coronary heart disease (CHD) risk measures were the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) single nucleotide polymorphism (SNP) P12A, insulin receptor substrate-1 (IRS-1) SNP G972R, one novel SNP of lipoprotein lipase (LPL), and three novel SNPs from acetyl-CoA carboxylase-beta (ACC-beta). Significant association of genotype frequency with PCOS was determined by Pearson chi-square tests. Generalized linear modeling was utilized to test for association of genotype with subclinical measures of CHD, including insulin resistance (HOMA-IR) and C-reactive protein (CRP). The 8-year prevalence of T2DM was 13.4% in PCOS cases and 5.8% in controls. After adjusting for age and BMI, women with PCOS had an estimated 2-fold risk of developing T2DM compared to normal control women. When stratified by body mass index (BMI) and controlling for age, PCOS cases with BMI > 35 kg/m2 were estimated to have 5x higher risk of developing T2DM. There were no significant associations between genotype frequencies and PCOS for Caucasian or African American subjects. However, the G972R variant of IRS-1 and PCOS significantly interacted to affect CRP concentrations indicating that cases with the R allele had significantly elevated CRP compared to all other permutations of G972R and PCOS status interaction. The final CRP model explained 22% of variability in CRP concentrations. In conclusion, the significant risk of T2DM attributed to women by PCOS was not explained by genetic SNPs analyzed here, however, a significant association of G972R and G972RxPCOS interaction with CRP concentrations was found, further supporting the growing body of evidence of associations between insulin resistance and systemic inflammation.
42

THE ALLEGHENY COUNTY SHORT-TERM AIR POLLUTION EFFECTS (SHAPE) STUDY ON THE ELDERLY

Mujuru, Priscah 09 June 2005 (has links)
A few studies have assessed the effects of the current levels of air quality in relation to stationary and indoor emission sources, monitoring sites and susceptible populations. To address this issue, first, an ecological evaluation of admissions of the elderly aged ≥65 years and the PM10 for the period 1995-2000 was carried out to assess vulnerability of this population. Secondly, a longitudinal study was conducted during the period of May 2003 to May 2004 among adults aged 50 to 79 years who had a cardiopulmonary diagnosis and resided in Allegheny County. Each participant maintained a diary of symptoms, peak expiratory flow rates and daily activities for up to two months.The ecological data showed high rates of admissions among the elderly. Individuals admitted multiple times often had a diagnosis related to acute conditions compared to the chronic diagnoses among those admitted only one-time. The admission category of whether an individual was admitted multiple times or one-time appeared to be significantly related to the PM10. The longitudinal study included a total of 32 participants, mean age 66. The average 24-hr PM10 level was 24.36 µg/m3. The results showed an association between PM10 and the cardiopulmonary symptoms suggesting a possible effect of air pollution. Additionally, the results of the continuous monitoring sites were highly correlated during both study periods. This finding proposes a review of the current federal and county air pollution monitoring strategies. Efforts should be re-directed at appropriate apportionment of individuals exposure levels and examining possible sources of emissions that impact the living environments. This can be achieved through personal monitoring in conjunction with physiological assessments for improved exposure-outcome extrapolation. The public health significance of this study is that the less severe incidences reported by participants do not often require urgent medical support, but can eventually burden the bodys physiological mechanism leading to hospitalization or death. The implication of the results is that the current ambient air quality standards do not appear to be entirely protective of all different population groups. The elderly who have underlying health conditions appear to be susceptible to the current exposure levels.
43

Ethnic and Gender Differences in the Correlates of Bone Mineral Density

Hill, Deanna D. 14 June 2005 (has links)
Osteoporosis is an important public health concern because of the significant morbidity and mortality associated with osteoporotic fractures. It is well established that ethnic and gender differences influence osteoporosis risk, but the etiology of these differences is not well studied. The goals of this research were to examine correlates of hip bone mineral density (BMD) and rates of bone loss among persons of African ancestry in three complementary analyses. In the first analysis, correlates of BMD were identified for 1,784 Tobagonian males, aged 40-84 years. BMD was inversely associated with age, height, and history of a broken bone. Lean mass, working on a fishing boat, and diabetes were positively associated with BMD. Correlates explained 25% of the variability in hip and femoral neck BMD. Correlates of BMD were also identified for 340 postmenopausal Tobagonian females, aged 50-94 years. BMD was positively associated with weight, thiazide diuretics, aspirin, recent back pain, and diabetes. BMD was inversely associated with age, thyroid medication, family history of fracture, and beta-blockers. Correlates explained 37% - 38% of the variability in hip and femoral neck BMD. Lastly, ethnic differences in rates of bone loss within gender were investigated among 457 Caucasian and 121 African American males and females, aged 65-87 years. Baseline and follow-up BMD was measured four years apart. African American males lost significantly less hip BMD compared to Caucasian males (-0.04% vs. -0.45%), after adjusting for covariates. Longitudinal changes in lean and fat mass explained more variability in rates of bone loss than weight, after adjustment for covariates. In conclusion, BMD was approximately one standard deviation higher among Tobagonians, despite gender, compared to NHANES data for African American males and females. Correlates of BMD were similar across gender among Tobagonians. Interestingly, older African American females had rates of bone loss that were comparable to Caucasian females, while African American males experienced significantly lower rates of hip bone loss. With our aging society and longer life expectancies for persons of African ancestry, the public health significance of this research is that osteoporosis may have a greater impact among minorities in the future.
44

Blunt trauma associated with increased cardiovascular morbidity

Ismailov, Rovshan 13 September 2005 (has links)
Cardiovascular diseases and trauma are two major public health issues. Evidence from numerous clinical case reports suggests that trauma may lead to various cardiovascular disorders, such as acute myocardial infarction, cardiac valve disorders and arrhythmias. Various mechanisms of such associations have been suggested; however, no population based studies have been conducted. Population-based studies are important in that they reduce the potential for selection bias and confounding, both of which may limit the interpretation of case reports. In addition, population based studies which include control groups provide quantitative estimates of association. We hypothesize that trauma is significantly associated with increased risk for certain cardiovascular disorders. To examine this issue, we conducted a cross-sectional analysis of the association between certain types of trauma (i.e. blunt cardiac injury (BCI), blunt thoracic injury, blunt abdominal/ pelvic trauma) and certain cardiac disorders (cardiac valve insufficiency and acute myocardial infarction) based on a large database of all hospital discharges from 19 states during a one-year period. We also conducted a matched case-control study of the association between blunt cardiac and thoracic injury and cardiac arrhythmias. Both the exposure (trauma) and the disease (cardiovascular disorders) were identified based on ICD-9-CM codes. Various confounding factors have been identified through the database. Unadjusted, multivariate logistic and the conditional adjusted multivariable regression analyses were performed. Independent of potential confounding factors, discharge for BCI was associated with a 12-fold increased risk for tricuspid valve insufficiency, incompetence, regurgitation or stenosis and a 3.4-fold increased risk for aortic valve insufficiency, incompetence, regurgitation or stenosis. Independent of confounding factors and coronary arteriography status, direct trauma to the heart was associated with a 3-fold increased risk for acute myocardial infarction in persons 46 years or older. When the diagnosis of acute myocardial infarction was confirmed by coronary arteriography, BCI was associated with a 5-fold risk elevation among patients 46 years and older and a 44-fold elevation among patients 45 years and younger. Abdominal or pelvic trauma, irrespective of confounding factors and coronary arteriography status, was associated with a 70% increase in the risk of acute myocardial infarction among patients 45 years and younger and a 3-fold increase among patients 46 years and older. We also found that after adjusting for potential confounders, patients 45 years and younger diagnosed with BCI had 13-fold increase in the risk of cardiac arrhythmia. This research has public health significance because it represents one of very few attempts to look at the association between two major health issues - namely trauma and cardiovascular disorders at such a large population based level. With the findings that several types of traumatic injury (such as thoracic, cardiac, abdominal and pelvic) are associated with an increased risk of specific cardiovascular disorders namely cardiac valve insufficiency, acute myocardial infarction and cardiac arrhythmias, it appears that trauma may play an important and heretofore largely unrecognized role in a portion of the national burden of cardiovascular morbidity and mortality.
45

HYPOVOLIMIC SHOCK: QUANTIFYING THE RISK OF HYPOTENSION AND HYPOTHERMIA IN SEVERELY INJURED TRAUMA PATIENTS

Zenati, Mazen Sahfik 13 September 2005 (has links)
Public Health Significance: Trauma represents the leading cause of mortality for young adults in their most productive years and incurs substantial short and long term disability. Death from trauma results in an annual loss of 492 years of productivity per 100,000 and costs $230 million a day. Most of these mortality and related medical expenses incurred early during the critical care unit stay. Improving the outcome during ICU phase will have substantial effects on trauma mortality and morbidity. Subjective: Hypovolemic shock is a major consequence of trauma and usually represented with hypotension and hypothermia. Despite the documented risk of hypotension and hypothermia in increasing mortality and morbidity, that risk has not been practically quantified. In this study, we assessed the effect of hypotension and hypothermia severity on the outcome during first and second ICU days. Methods: Trauma patients admitted to University of Pittsburgh trauma center during 1999-2000 were reviewed (n=783). Data on patients demography, injury, vital signs, diagnosis, and outcome have been collected. The lowest recorded systolic blood pressure and duration in minutes of all episodes of SBP less or equal to 90 mm Hg were collected. The lowest temperature and duration in minutes of all episodes of hypothermia of less or equal to 36 °C were also obtained. The outcome variable was death during hospitalization and length of ICU stay. Relative risk, Pearson Chi2, t-test, regression, and survival analysis were used. Results: Patients with hypotension during the first 48 hours in ICU and hypothermia during the first 24 hours of ICU had an increased risk of mortality. The length of ICU stay increased upon the increase in the severity of hypotension and hypothermia. Each 5-degree reduction in SBP and 1°C reduction in temperature increased the risk of mortality by 1.37 and 1.51 respectively. Each 1-hour increase in SBP and temperature increased the mortality by 1.22 and 1.10 respectively. Conclusion: A brief episode of hypotension during ICU day one was associated with increased mortality and mortality. For patients who survived ICU day one, hypotension in ICU day two predicts the outcome better than hypotension records of ICU day one. Hypothermia added significant information beside hypotension in quantifying the risk of shock. Hypotension and hypothermia should not only be treated promptly but also should be prevented.
46

A Longitudinal Study Of Community-Associated Methicillin-Resistant Staphylococcus aureus Colonization In College Sports Participants

Jimenez Truque, Natalia 11 April 2013 (has links)
Staphylococcus aureus is the leading cause of invasive infections and skin and soft tissue infections in the United States. Athletes have higher risk of infection with S. aureus than the general population. Though carriage of S. aureus increases the risk of infection, most studies in athletes have not assessed carriage and have included mostly male contact sports participants. Thus, the natural history of carriage in different sports is poorly understood, and strategies to prevent infections in athletes are not clear. To better understand carriage of S. aureus and to identify its risk factors, we collected nasal and throat samples from all Vanderbilt University varsity athletes for two academic years. Staphylococcal carriage was highest during the summer. Contact sports athletes had higher risk of carrying S. aureus over time: they had higher carriage and they carried S. aureus for longer periods of time than athletes in noncontact sports. Also, athletes acquired S. aureus more quickly if they played contact sports. Athletes in contact sports, and particularly in football, were more likely to carry the current epidemic clone of MRSA (USA300) that is associated with substantial morbidity and mortality. These findings indicate that contact sports participation, particularly football, increases athletes risk of carrying S. aureus. These findings also suggest that efforts to prevent transmission of S. aureus among athletes should be focused on contact sports teams after the summer break, when carriage was highest.
47

Development of a lung cancer prediction model for surgeons and factors affecting its national application

Deppen, Stephen Andrew 04 August 2013 (has links)
Lung cancer is deadly, killing more people than breast, colon and prostate cancer combined. Surgeons evaluating patients for lung cancer face a dilemma: to operate and subject the individual to operation associated mortality and morbidity or not operate and possibly miss early diagnosis and treatment. No models designed for surgeons evaluating lung lesions. We successfully estimated the TREAT model. A model designed for surgeons with an internally validated AUC of 0.87 and Brier score of 13. If the TREAT model is applied to a national population, its accuracy may decrease due to local conditions. To determine the possible extent of such variation, benign disease prevalence after lung surgery was estimated using 2009 Medicare hospital discharge data. Significant variation in benign disease prevalence between states was observed with a low of 1.3% in Vermont and a high of 25% in Hawaii. The causes for this observed variation are unknown. Residence in a county with high fungal lung disease prevalence was not associated with increased likelihood of benign disease. FDG-PET scan variance was observed in the national ACOGOS Z4031 trial. FDG-PET sensitivity (82%) and specificity (31%) were significantly lower than in previous published studies. Granuloma occurred in 68% of the false positive FDG-PET scans and sensitivity varied significantly between sites. Scan accuracy increased with increasing lung lesion size. Whether the observed variation is caused by practice variation, referral patterns, fungal lung disease, or other factors is unknown. A meta-analysis examined FDG-PET accuracy to diagnose lung lesions sought to determine if other researchers had observed variance in FDG-PET accuracy. Seven studies reported false positive scans arising from granulomas caused by infectious lung disease. Specificity of those studies was 59%, significantly lower than the specificity (77%) observed in the remaining 53 studies. Studies whose mean lesion size was less than or equal to 20 mm had significantly lower sensitivity than studies conducted in larger lesions. The TREAT model shows clinical promise and should be externally validated. The causes of observed variation in benign disease prevalence and FDG-PET accuracy should be investigated with particular attention made to measuring infectious disease exposures that cause granulomas.
48

BONE MINERAL DENSITY (BMD), BONE LOSS AND CORONARY CALCIFICATION IN OLDER MEN

Lee, Miryoung 10 January 2003 (has links)
Cardiovascular disease (CVD) and osteoporosis are important public health burdens in older men. Recent epidemiologic studies suggest that osteoporosis and atherosclerosis may be linked. The goals of this study were to determine whether measures of bone strength were related to coronary artery calcification (CAC). To further test the underlying etiologic pathways, we explored 1) the relationship of estrogen and C-reactive protein (CRP) and 2) the genetic contribution of osteoprotegerin (OPG) polymorphisms. A total of 138 Caucasian men aged 51 to 78 years were participated in present study. Hip BMD, CRP and sex steroid hormones were measured, and annualized percent change in BMD was calculated. CAC score was measured by electron beam tomography. Men were genotyped for T-950C and G-1181C polymorphisms in OPG gene. Correlation analysis, analysis of variance (ANOVA), and regression analysis were employed to evaluate the study aims. The prevalence of CAC increased with age, ranging from median value of 152 at less than 65 years to 788 at 80 years and older. Hip BMD or bone loss at the hip was not correlated with CAC. Neither serum estrogen nor CRP was related to bone loss or coronary calcification. There were no significant differences in BMD across OPG T-950C or G-1181C genotypes. However, men with T-950C C/C genotype were more likely to lose BMD at the intertrochanter compared with men with T/T or T/C genotypes (p =0.03). Calcaneal BUA significantly differed across G-1181C genotypes; men with C/C genotypes had 25% higher BUA values than men with G/G genotypes. Interestingly, men with C/C genotypes had 0.5SD higher coronary calcification than men with G/G genotypes, which persisted after adjusting for age (p=0.03). There was a significant dose dependent effect across genotypes (p=0.01). In conclusion, we could not find any relationship between measures of bone strength and coronary calcification in older men. However, our findings suggest that genetic variations in OPG may be of importance to examine its effect on the development of coronary calcification in older men.
49

NEEDS ASSESSMENT OF THE EPIDEMIOLOGICAL INFORMATION SYSTEM IN THE MEXICAN INSTITUTE OF SOCIAL SECURITY

Rico Verdin, Beatriz 15 August 2003 (has links)
The IMSS is updating their information systems. The epidemiological information systems are one of the most important information sources to define health policies. We analyzed epidemiologists¡¦ needs of epidemiological information systems; described utilization of these systems, and explored epidemiologists¡¦ attitudes towards utilization of computer applications. During summer 2002 we applied a survey. We included epidemiologists who were active workers and excluded participants that answered less than 80% of the questionnaire. From 467 participants 34.7% were females, age 46.56(b5.92), 99.4% physicians, 48% work in primary care units. Epidemiologists have been performing their current position 7.86 years (¡Ó6.02). Almost 67% have computer, 22.3% e-mail and 35.3% Internet access. Those with computers access spent less time filling forms and more time doing data processing. Epidemiologists with information technology access developed stronger networks and communications channels than those who didn¡¦t. Just 13% of the epidemiologists have published at least one article, those with computers published 1.83 more times than those who didn¡¦t, 34% are doing research activities, those with computers did 1.65 more research activities than those without, and participants with Internet access did 1.74 more research than those who didn¡¦t. Epidemiologists¡¦ opinion about the accuracy of epidemiological information systems wasn¡¦t influenced by computer access (X2= 60.86, p<.001), e-mail (X2=1.94, p=.20) and Internet (X2=1.94, p=.16). Epidemiologists who have computers opined 23% more that notification channels are slow than those who didn¡¦t (X2=1.20, p=.27) and, those who have Internet access agreed 38% more (X2=2.65, p=.10) and who have e-mail opined 68% more (X2=5.36, p=.02). Epidemiologists who have computers agreed 30% more that notification forms are accurate than those who didn¡¦t (X2=1.31, p=.25) and those with Internet access agreed 1.54 more times (X2=3.83, p=.05). There weren¡¦t differences among information technology access and epidemiologists¡¦ agreement towards the convenience of computer applications, as well as consequences of computer applications. There weren¡¦t differences among epidemiologists¡¦ age, gender, time in job position, working time in IMSS and job position and opinions about desirability of computer applications. Epidemiologists¡¦ opinions were that epidemiological information systems are working well but have to be improved some areas. There was acceptance toward IHC in public health.
50

OPTIMIZATION OF A SEROLOGICAL ASSAY SYSTEM FOR ESTABLISHING INFECTION OF KAPOSI'S SARCOMA ASSOCIATED HERPESVIRUS (KSHV) IN MULTIPLE POPULATIONS AT VARYING LEVELS OF RISK

Laney, Anthony Scott 03 February 2006 (has links)
Background: Kaposis sarcoma-associated herpesvirus (KSHV or HHV-8) is the etiologic agent of Kaposis sarcoma (KS), multicentric Castlemans disease (MCD), and primary effusion lymphoma (PEL). KSHV is a nonubiquitous herpesvirus (~3% in the general US population) that can cause significant morbidity and mortality among immunocompromised hosts. However, routine surveillance of KSHV is lacking because diagnostic systems for viral identification are not of high enough sensitivity and specificity. This research describes a novel KSHV serological algorithm which increases sensitivity and specificity of KSHV detection beyond what has been previously reported. Methods: A novel KSHV assay algorithm based on a baculovirus-expressed LANA1-GST fusion protein was used with previously described KSHV lytic antigen ELISAs. Initial assay evaluation was performed using 90 case sera from persons with AIDS- KS and 100 blood donor controls. We identified two multi-antigen algorithms: one that maximized sensitivity and one that maximized specificity. Sera from patients requiring bone-marrow transplantation, cadaveric renal transplant donors (CRTD), patients with systemic lupus erythematosus (SLE) and subjects with primary (PPH) and secondary pulmonary hypertension were obtained for KSHV testing. Results: The highly sensitive algorithm yielded a sensitivity of 96% and a specificity of 94% and the highly specific algorithm a sensitivity of 93% and a specificity of 98%. Among CRTD, using the highly specific algorithm, overall seroprevalence was low at 4.0% (2/50) and similar to blood donors (P=0.46; OR=1.4; CI=0.14, 7.9). With the more specific algorithm, 8.0% (4/50) were infected compared to 6.4% (16/250) among blood donors (OR=1.3; CI=0.41,4.0; P=0.43). Among subjects requiring bone marrow transplantation seroprevalence was 3.0% and 10.0% and did not differ from blood donors (OR=2.0; 95% CI=0.10,122.9; P=0.50). Higher KSHV seroprevalence was observed among SLE patients using the specific algorithm (OR=6.0; 95% CI, 1.2-29.0) and the sensitive algorithm (OR=3.6; 95% CI, 1.1-12.2) though this is likely due to antigenic cross-reactivity as opposed to actual infection. Among patients with PPH we found no evidence of KSHV infection (0/19). Conclusions: We used a systematic approach to standardize the assessment of KSHV infection rates and examined seroprevalence rates among high-risk populations of clinical interest. KSHV is of public health importance because it leads to cancer in immunocompromised hosts. Future studies of KSHV should focus on the cost-effectiveness of implementing surveillance systems such as the one described here, which could potentially lead to a marked reduction in KSHV-associated morbidity and mortality.

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