26 resultados para 420200 Literature Studies

em DigitalCommons@The Texas Medical Center


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A wealth of genetic associations for cardiovascular and metabolic phenotypes in humans has been accumulating over the last decade, in particular a large number of loci derived from recent genome wide association studies (GWAS). True complex disease-associated loci often exert modest effects, so their delineation currently requires integration of diverse phenotypic data from large studies to ensure robust meta-analyses. We have designed a gene-centric 50 K single nucleotide polymorphism (SNP) array to assess potentially relevant loci across a range of cardiovascular, metabolic and inflammatory syndromes. The array utilizes a "cosmopolitan" tagging approach to capture the genetic diversity across approximately 2,000 loci in populations represented in the HapMap and SeattleSNPs projects. The array content is informed by GWAS of vascular and inflammatory disease, expression quantitative trait loci implicated in atherosclerosis, pathway based approaches and comprehensive literature searching. The custom flexibility of the array platform facilitated interrogation of loci at differing stringencies, according to a gene prioritization strategy that allows saturation of high priority loci with a greater density of markers than the existing GWAS tools, particularly in African HapMap samples. We also demonstrate that the IBC array can be used to complement GWAS, increasing coverage in high priority CVD-related loci across all major HapMap populations. DNA from over 200,000 extensively phenotyped individuals will be genotyped with this array with a significant portion of the generated data being released into the academic domain facilitating in silico replication attempts, analyses of rare variants and cross-cohort meta-analyses in diverse populations. These datasets will also facilitate more robust secondary analyses, such as explorations with alternative genetic models, epistasis and gene-environment interactions.

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We postulated that neuromuscular disuse results in deleteriously affected tissue-vascular fluid exchange processes and subsequently damages the important oxidative bioenergetic process of intramuscular lipid metabolism. The in-depth research reported in the literature is somewhat limited by the ex vivo nature and sporadic time-course characterization of disuse atrophy and recovery. Thus, an in vivo controlled, localized animal model of disuse atrophy was developed in one of the hindlimbs of laboratory rabbits (employing surgically implanted tetrodotoxin (TTX)-filled mini-osmotic pump-sciatic nerve superfusion system) and tested repeatedly with magnetic resonance (MR) throughout the 2-week period of temporarily induced disuse and during the recovery period (following explantation of the TTX-filled pump) for a period of 3 weeks. Controls consisted of saline/"sham"-implanted rabbit hindlimbs. The validity of this model was established with repeated electrophysiologic nerve conduction testing using a clinically appropriate protocol and percutaneously inserted small needle stimulating and recording electrodes. Evoked responses recorded from proximal (P) and distal (D) sites to the sciatic nerve cuff in the TTX-implanted group revealed significantly decreased (p $<$ 0.001) proximal-to-distal (P/D) amplitude ratios (as much as 50-70% below Baseline/pre-implanted and sham-implanted group values) and significantly increased (p $<$ 0.01) differential latency (PL-DL) values (as much as 1.5 times the pre- and sham-implanted groups). By Day 21 of recovery, observed P/D and PL-DL levels matched Baseline/sham-implemented levels. MRI-determined cross-sectional area (CSA) values of Baseline/pre-implanted, sham- or TTX-implanted, and recovering/explanted and the corresponding contralateral hindlimb tibialis anterior (TA) muscles normalized to tibial bone (TB) CSA (in TA/TB ratios) revealed that there was a significant decline (indicative of atrophic response) from pre- and sham-implanted controls by as much as 20% (p $<$ 0.01) at Day 7 and 50-55% (p $<$ 0.001) at Day 13 of TTX-implantation. In the non-implanted contralaterals, a significant increase (indicative of hypertrophic response) by as much as 10% (p $<$ 0.025) at Day 7 and 27% (p $<$ 0.001) at Day 13 + TTX was found. The induced atrophic/hypertrophic TA muscles were observed to be fully recovered by Day 21 post-explantation as evidenced by image TA/TB ratios. End-point biopsy results from a small group of rabbits revealed comprehensive atrophy of both Type I and Type II fibers, although the heterogeneity of the response supports the use of image-guided, volume-localized proton magnetic resonance spectroscopy (MRS) to noninvasively assess tissue-level metabolic changes. MRS-determined results of a 0.25cc volume of tissue within implanted limb TA muscles under resting/pre-ischemic, ischemic-stressed, and post-ischemic conditions at timepoints during and following disuse atrophy/recovery revealed significantly increased intramuscular spectral lipid levels, as much as 2-3 times (p $<$ 0.01) the Baseline/pre-implanted values at Day 7 and 6-7 times (p $<$ 0.001) at Day 13 + TTX, which approached normal levels (compared to pre- and sham-implanted groups) by Day 21 of post-explanation recovery. (Abstract shortened by UMI.) ^

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The purpose of this research was to determine if principles from organizational theory could be used as a framework to compare and contrast safety interventions developed by for-profit industry for the time period 1986–1996. A literature search of electronic databases and manual search of journals and local university libraries' book stacks was conducted for safety interventions developed by for-profit businesses. To maintain a constant regulatory environment, the business sectors of nuclear power, aviation and non-profits were excluded. Safety intervention evaluations were screened for scientific merit. Leavitt's model from organization theory was updated to include safety climate and renamed the Updated Leavitt's Model. In all, 8000 safety citations were retrieved, 525 met the inclusion criteria, 255 met the organizational safety intervention criteria, and 50 met the scientific merit criteria. Most came from non-public health journals. These 50 were categorized by the Updated Leavitt's Model according to where within the organizational structure the intervention took place. Evidence tables were constructed for descriptive comparison. The interventions clustered in the areas of social structure, safety climate, the interaction between social structure and participants, and the interaction between technology and participants. No interventions were found in the interactions between social structure and technology, goals and technology, or participants and goals. Despite the scientific merit criteria, many still had significant study design weaknesses. Five interventions tested for statistical significance but none of the interventions commented on the power of their study. Empiric studies based on safety climate theorems had the most rigorous designs. There was an attempt in these studies to address randomization amongst subjects to avoid bias. This work highlights the utility of using the Updated Leavitt's Model, a model from organizational theory, as a framework when comparing safety interventions. This work also highlights the need for better study design of future trials of safety interventions. ^

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Case control and retrospective studies have identified parental substance abuse as a risk factor for physical child abuse and neglect (Dore, Doris, & Wright, 1995, May; S. R. Dube et al., 2001; Guterman & Lee, 2005, May; Walsh, MacMillan, & Jamieson, 2003). The purpose of this paper is to present the findings of a systematic review of prospective studies from 1975 through 2005 that include parental substance abuse as a risk factor for physical child abuse or neglect. Characteristics of each study such as the research question, sample information, data collection methods and results, including the parent assessed and definitions of substance abuse and physical child abuse and neglect, are discussed. Five studies were identified that met the search criteria. Four of five studies found that parental substance abuse was a significant variable in predicting physical child abuse and neglect.^

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Background. Risk factors underlying the development of Barrett's esophagus (BE) are poorly understood. Recent studies have examined the association between elevated body mass index (BMI) and BE with conflicting results. A systematic review of literature was performed to study this association.^ Methods. Cross-sectional, case control and cohort studies published through April 2007 meeting strict inclusion and exclusion criteria were included. A thorough data abstraction, including that of reported crude or adjusted odds ratios or mean BMI, was performed. Crude odds ratios were estimated from available information in 3 studies.^ Results. Of 630 publications identified by our search items, 59 were reviewed in detail and 12 included in the final analyses. 3 studies showed a statistically significant association between obesity and BE (30-32) while 2 studies found a statistically significant association between overweight and BE (31, 32). Two studies that reported BMI as a continuous variable found BMI in cases to be significantly higher than that in the comparison group (30, 32). Other studies failed to show an significant association between elevated BMI and BE.^ Conclusions. There is conflicting data regarding the association between elevated BMI and BE. It is important to identify other risk factors that in combination with elevated BMI may lead to BE. Further studies are needed to evaluate if the presence of reflux symptoms or any particular pattern of obesity, are independently associated with BE.^ Key words. Barrett's esophagus, obesity, Body Mass Index, gastroesophageal reflux disease, meta-analysis^

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The preterm birth rate has been increasing over time in the United States, causing a large social and individual financial burden. Though the cause of preterm birth is now known, risk factors such as a previous preterm birth and a short cervical length have been identified as possible predictors. There are many contributing social and behavioral factors that play a role was well as medical problems that occur before and during pregnancy. Though there have been prevention methods identified, such as prenatal care, tocolytic therapy and cervical cerclage, none of these methods have shown to definitively prevent preterm birth over a long period of time. 17 alpha hydroxyprogesterone has been recognized as a possible prevention method for women at high risk for preterm birth. Three out of the five studies assessed in this review showed a significant reduction in preterm birth with administration of progesterone, both for women with a previous preterm birth and with a short cervical length. Currently there is no standard of care for those at high risk for preterm birth. More large clinical trials need to be conducted to determine if this progesterone for the prevention of preterm birth is effective. ^

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Naltrexone, an opioid antagonist, was the second drug approved for treatment of alcohol dependence in the U.S. Its approval followed two landmark studies published in the U.S. in 1992. [1, 2] These studies showed that a combined treatment of naltrexone and behavioral therapy reduced alcohol consumption in alcoholics. Opioid antagonists decrease craving for alcohol and help to reduce drinking by blocking opioid peptide receptors in the body that are active in a dopamine chemical reward system. ^ Despite their usefulness, opioid antagonists have been underutilized. Health providers not educated in the use of opioid antagonists hold the view that opioid antagonist therapy is ineffective. However, it is apparent from the relevant literature that this therapy, when properly understood and targeted, has the potential to make a positive contribution in treating alcohol dependent patients. ^ This thesis will review the scientific literature and the present body of knowledge regarding opioid antagonists (naltrexone) and their pharmacological role in treating alcohol dependence.^

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A review of literature was carried out regarding sexually related factors, sexually transmissible diseases (STD's) and infections with prostate cancer (PC) development risk. The review of literature, in conjunction with the tabulation of studies, suggested that ejaculation and circumcision may play a protective role in the development of PC and that multiple sex partners and an active sex life may play a causal role in the development of PC which may negate and counteract the protective effects of ejaculation and circumcision. HIV infection may plausibly play a function in deteriorating and compromising immune controls on carcinogenesis. Because of the coexistence of a highly active sexual lifestyle and sexual promiscuity with the growing occurence of STD's, their maybe a correlation with the high incidence of prostate cancer in the United States. Potential multi-institutional studies are warranted to confirm the high incidence of this neoplasm with the increasing cases of STD's and if in fact there is a proportional association to further elucidate the factors responsible for its high incidence.^

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Background. Because it is important to minimize children's sun exposure to reduce skin cancer risk, much of the extensive skin cancer prevention literature consists of studies of children's sun protection, sun avoidance and ultraviolet radiation (UVR) exposure. Little attention has been focused on the measurement of psychosocial constructs in these studies. Identification of the psychosocial correlates or determinants of children's skin cancer risk or risk-reduction behavior is critical to more fully understand and predict behavior. Furthermore, psychosocial variables may be influenced by interventions to reduce risk. Thus, it is important to examine the psychosocial measures used in studies of children's skin cancer prevention. Information on the validity and reliability of psychosocial measures may increase confidence in study findings based on these measures. In particular, self-efficacy and barriers are key constructs in several major theoretical frameworks and parental measures have been associated with children's sun protection. However, there is conceptual overlap of self-efficacy and barriers measures and little is known about the psychometric properties of these measures.^ Study Aims and Methods. The overall goal of this dissertation was to examine the measurement of psychosocial constructs relevant to children's skin cancer prevention. Because children depend primarily on their parents for skin cancer prevention, measures of parents' psychosocial constructs are the focus. Study 1 was a systematic review of parental psychosocial measures used in studies of children's sun protection, sun avoidance and UVR exposure. The specific aims of Study 1 were to (1) describe psychosocial measures reported by parents, including available information on the psychometric properties of these measures and their use in analyses and (2) provide recommendations for the development, refinement and standardized reporting of measures. ^ Study 2 examined the psychometric properties of measures of parental self-efficacy and barriers regarding children's sun protection. Melanoma patients (N=205) who were parents of children ≤ 12 years of age completed a telephone interview that included self-efficacy and barriers measures specific to sunscreen, clothing, shade and limiting time outdoors. The specific aims of Study 2 were to (1) use a confirmatory factor analytic approach to examine the factorial validity of parental self-efficacy and barriers measures, (2) examine the convergent and discriminant validity of behavior-specific measures of self-efficacy and barriers and (3) assess the reliability of item and scale measures.^ Results. In Study 1, a search of standard databases yielded 48 eligible studies. Most studies assessed only one or two psychosocial constructs. Knowledge was measured most frequently. There was little discussion of measure source, development, theoretical background or psychometric properties, besides internal consistency reliability. There was conceptual overlap of some measures. In Study 2, confirmatory factor analytic findings supported the factorial validity of the self-efficacy and barriers measures. When all eight self-efficacy and barriers measures were included in the same model, a modified eight-factor model adequately fit the data, providing preliminary evidence that the measures are distinct. Measure associations supported the convergent validity of all measures and the discriminant validity of most measures. The self-efficacy and barriers measures were reliable.^ Conclusions. Recommendations based on the literature review include developing and refining psychosocial measures based on theory. Describing a measure's theoretical basis and psychometric properties would facilitate critical evaluation. Standardized reporting of source, development, theory, construct, items and analytic role would facilitate comparison of findings, continual refinement and future applications of measures. In the validation study, self-efficacy and barriers measures were examined in a sample of parents with a personal history of melanoma. Findings suggested that these measures are valid and reliable for use in studies of children's sun protection. There was preliminary evidence that these measures are distinct but additional study is needed. ^

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Background. Because our hands are the most common mode of transmission for bacteria causing hospital acquired infections, hand hygiene practices are the most effective method of preventing the spread of these pathogens, limiting the occurrence of healthcare-associated infections and reducing transmission of multi-drug resistant organisms. Yet, compliance rates are below 40% on the average. ^ Objective. This culminating experience project is primarily a literature review on hand hygiene to help determine the barriers to hand hygiene compliance and offer solutions on improving these rates and to build on a hand hygiene evaluation performed during my infection control internship completed at Memorial Hermann Hospital during the fall semester of 2005. ^ Method. A review of peer-reviewed literature using Ovid Medline, Ebsco Medline and PubMed databases using keywords: hand hygiene, hand hygiene compliance, alcohol based handrub, healthcare-associated infections, hospital-acquired infections, and infection control. ^ Results. A total of eight hand hygiene studies are highlighted. At a children's hospital in Seattle, hand hygiene compliance rates increases from 62% to 81% after five periods of interventions. In Thailand, 26 nurses dramatically increased compliance from 6.3% to 81.2% after just 7 months of training. Automated alcohol based handrub dispensers improved compliance rates in Chicago from 36.3% to 70.1%. Using education and increased distribution of alcohol based handrubs increased hand hygiene rates from 59% to 79% for Ebnother, from 54% to 85% for Hussein and from 32% to 63% for Randle. Spartanburg Regional Medical Center increased their rates from 72.5% to 90.3%. A level III NICU achieved 100% compliance after a month long educational campaign but fell back down to its baseline rate of 89% after 3 months. ^ Discussion. The interventions used to promote hand hygiene in the highlighted studies varied from low tech approaches such as printed materials to advanced electronic gadgets that alerted individuals automatically to perform hand hygiene. All approaches were effective and increased compliance rates. Overcoming hand hygiene barriers, receiving and accepting feedback is the key to maintaining consistently high hand hygiene adherence. ^

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Background. This culminating experience project was inspired by an independent study conducted at The University of Texas School of Public Health with Dr. Andrew Springer, DrPH, who works on the evaluation of the Coordinated Approach to Child Health (CATCH) program in Travis County, Texas. It was indicated that a social marketing plan could enhance current efforts for the CATCH program. The aims of the project were to (1) review and synthesize literature on social marketing, with a specific focus on diet, physical activity, and obesity prevention; and (2) apply the gained knowledge toward a practical solution – a social marketing plan for the CATCH program.^ Methods. The literature review aimed to answer the following questions: (1) What audiences (ethnic and age groups), settings, health behaviors, and behavioral science theories have been used in social marketing campaigns? (2) What features of social marketing were used (e.g. formative research, segmentation, and the marketing mix - including promotional strategies and communication channels)? (3) What were the outcomes of the social marketing campaigns? The search aimed to identify studies that met the following inclusion criteria: (a) The study explicitly stated that social marketing was used; (b) The intervention promoted physical activity and/or healthy eating; (c) The population was children, adolescents, young adults, and/or parents; (d) Results of the intervention were available in the published literature The literature review includes studies from the past five years (2004 to 2009). After reviewing the social marketing literature, the insight and knowledge gained was applied to develop a social marketing plan for the CATCH program. The plan was guided by Hands-on Social Marketing, A Step-by-Step Guide and the Center for Disease Control and Prevention's Social Marketing web course.^

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The approach to the diagnosis and treatment of congenital toxoplasmosis has been one of flux and debate, fueled by lack of knowledge, lack of consensus, different methods of screening and different national policies for screening in different parts of the world. Countries with higher prevalence of disease such as in Europe and South America have a heightened awareness of the need to screen and treat for this parasitic infection during pregnancy. In contrast, in the United States, it is a condition scarcely discussed and has been largely ignored except in some large centers and by a few researchers. Policies and research strategies for any condition should start with obtaining good data. The aims of this thesis included a review of prevalence studies conducted in the United States, focused on the past 20 years, combined with a description of original research conducted by the author several years ago. The latter was a cross-sectional study performed in Houston, one of the largest American cities with a great ethnic mix. The study analyzed prevalence rates of Toxoplasma gondii IgG antibody in sera of women of reproductive age. Overall seroprevalence was 12.3%. In keeping with other studies, higher prevalence correlated with lower socioeconomic status, Black and Hispanic and Asian ethnicities, and increasing age. A literature search revealed only three prevalence studies performed in the United States over the past 20 years, with another four studies only referred to as personal communications or within a textbook, without further study detail available. The literature review also revealed a lack of consensus on whether or not to screen for toxoplasmosis in pregnancy, and even whether or not treatment in utero is worthwhile.^ Proponents of screening and treatment in pregnancy site studies both in the United States and France, emphasize that treatment reduces disease manifestations in infants. Opponents cite other studies that show only marginal benefits, together with potential side effects of medication regimens and generation of anxiety in parents. What is agreed on so far is the value of educating pregnant women on how to avoid contracting toxoplasmosis, and educating physicians on making the best use of reference laboratories before major treatment decisions are made. Further research to reevaluate the literature critically, review new treatment regimens and examine costs and benefits of screening and treatment of toxoplasmosis in pregnancy, bringing together European and American researchers, is needed.^

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Streptococcus mutans has been identified as the primary etiological agent of human dental caries. Since its identification, there has been research focused on the development of a vaccine to prevent this disease. Preliminary research has been conducted to test both active and passive vaccines for Streptococcus mutans in animals and humans. Although a vaccine for dental caries caused by Streptococcus mutans would most likely be administered to children, no testing of any type of dental caries vaccines has been conducted on children as of yet. The public health imperative for the development of a vaccine is great. Not only will a vaccine reduce the various consequences, but it would also improve quality of life for many individuals. Among the many possible vaccine antigen candidates, researchers have also been focusing on protein antigens, GTFs, and Gbps as possible candidates for a vaccine. There are also many routes of administration under research, with topical, oral, and intranasal showing a lot of promise. This review will provide an overview on the current state of research, present key factors influencing prevalence of caries, and summarize and discuss the results of animal and human studies on caries vaccines against Streptococcus mutans. The progress and obstacles facing the development of a vaccine to fight dental caries will also be discussed. ^

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Approximately 200,000 African children are born with sickle-cell anemia each year. Research has shown that individuals with hemoglobin disorders, particularly sickle-cell anemia, have increased susceptibility to contracting malaria. Currently it is recommended that patients diagnosed with sickle-cell anemia undergo malaria chemoprophylaxis in order to decrease their chances of malarial infection. However, studies have shown that routine administration of these drugs increases the risk of drug resistance and could possibly impair the development of naturally acquired immunity. Clinical trials have shown intermittent preventive treatment (IPT) to be an effective method of protection against malaria. The objective of this report was to review previously conducted clinical trials that study the effects of intermittent preventive treatment on malaria and anemia in infants and children. Based on the review, implications for its appropriateness as a protective measure against malaria for infants and children diagnosed with sickle-cell disease were provided.^ The 18 studies reviewed were randomized controlled trials that focused on IPT’s effect on malaria (7 studies), anemia (1 study), or both (8 studies). In addition to these 16, one study looks at IPT’s effect on molecular resistance to malaria, and another study is a follow-up to a study in order to review IPT’s potential to cause a rebound effect. The 18 th study in this review specifically looks at IPT’s protective efficacy in children with SCA. The studies in this report were restricted to randomized controlled trials that have been performed from 2000 to 2010. Reports on anemia were included to illustrate possible added benefits of the use of IPT specific to burdens associated with SCA other than malaria susceptibility. The outcomes of these studies address several issues of concern involving the administration of IPT: protective efficacy (in reference to age, seasonal versus perennial malaria regions, and overall effectiveness against malaria and anemia), drug resistance, drug rebound effect, drug side-effects, and long-term effects. Overall, these showed that IPT has a significant level of protective efficacy against malaria and/or anemia in children. More specifically, the IPT study evaluating children diagnosed with sickle-cell anemia proved IPT to be a more effective method of protection than traditional chemoprophylaxis. ^

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Background. Children in the age group of 2-5 years spend substantial amount of time during the day in some kind of childcare setting. These settings are an excellent environmental infrastructure to enhance their nutrition and physical activity behavior and to promote healthy eating and physical activity habits. Due to the steep rise in overweight and obesity among children in the past three decades, it becomes essential to intervene early. There exists a need for literature on a comprehensive and sustainable approach to obesity prevention for younger children in these settings. ^ Methods. Systematic literature search was undertaken using databases like Medline Ovid, Pubmed, Medline Ebsco, and Cochrane Library. Articles published in English as well as English language abstracts of foreign articles were included. The inclusion criteria were as follows: (1) Studies conducted in any part of the world exploring relevant themes and a child care or preschool setting would be included. (2) The interventions promoted physical activity, nutrition/healthy eating/improved diet, reduced television viewing, reduced BMI, changed knowledge and behavior of children and or staff or affected policy/standards/regulations. (3) The population was children in the age group of at least 2 years to 5 years. (4) Articles published in English and English language abstracts for foreign articles would be included. ^ Results. 16 articles were included in the review that consisted of primary interventions in the form of randomized control trials or pre-post interventions were conducted in a preschool or child care or day care setting only. The outcomes pertaining to healthy weight in children were increased vegetable intake, reduced BMI and increased knowledge among others. ^ Conclusion. There is a dearth of data on strong intervention trials in the child care setting. Preschool research studies in the young children that have been conducted are not strong enough. There is a need for more randomized control trials and a well planned evaluation in the preschool age children. There is a need to develop outcome measures that can accurately assess the changes in diet and physical activity in this age group. Child care nutrition and physical activity standards need to be made stringent. ^