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Signatur des Originals: S 36/F09928

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Signatur des Originals: S 36/G10809

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Signatur des Originals: S 36/G03866

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Signatur des Originals: S 36/G03868

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Signatur des Originals: S 36/G03869

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DNA interstrand crosslinks (ICLs) are among the most toxic type of damage to a cell. Many ICL-inducing agents are widely used as therapeutic agents, e.g. cisplatin, psoralen. A bettor understanding of the cellular mechanism that eliminates ICLs is important for the improvement of human health. However, ICL repair is still poorly understood in mammals. Using a triplex-directed site-specific ICL model, we studied the roles of mismatch repair (MMR) proteins in ICL repair in human cells. We are also interested in using psoralen-conjugated triplex-forming oligonucleotides (TFOs) to direct ICLs to a specific site in targeted DNA and in the mammalian genomes. ^ MSH2 protein is the common subunit of two MMR recognition complexes, and MutSα and MutSβ. We showed that MSH2 deficiency renders human cell hypersensitive to psoralen ICLs. MMR recognition complexes bind specifically to triplex-directed psoralen ICLs in vitro. Together with the fact that psoralen ICL-induced repair synthesis is dramatically decreased in MSH2 deficient cell extracts, we demonstrated that MSH2 function is critical for the recognition and processing of psoralen ICLs in human cells. Interestingly, lack of MSH2 does not reduce the level of psoralen ICL-induced mutagenesis in human cells, suggesting that MSH2 does not contribute to error-generating repair of psoralen ICLs, and therefore, may represent a novel error-free mechanism for repairing ICLs. We also studied the role of MLH1, anther key protein in MMR, in the processing of psoralen ICLs. MLH1-deficient human cells are more resistant to psoralen plus UVA treatment. Importantly, MLH1 function is not required for the mutagenic repair of psoralen ICLs, suggesting that it is not involved in the error-generating repair of this type of DNA damage in human cells. ^ These are the first data indicating mismatch repair proteins may participate in a relatively error-free mechanism for processing psoralen ICL in human cells. Enhancement of MMR protein function relative to nucleotide excision repair proteins may reduce the mutagenesis caused by DNA ICLs in humans. ^ In order to specifically target ICLs to mammalian genes, we identified novel TFO target sequences in mouse and human genomes. Using this information, many critical mammalian genes can now be targeted by TFOs.^

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This study is a retrospective longitudinal study at Texas Children's Hospital, a 350-bed tertiary level pediatric teaching hospital in Houston, Texas, for the period 1990 to 2006. It measured the incidence and trends of positive pre-employment drug tests among new job applicants At TCH. ^ Over the study period, 16,219 job applicants underwent pre-employment drug screening at TCH. Of these, 330 applicants (2%) tested positive on both the EMIT and GC/MS. After review by the medical review officer, the number of true drug test positive applicants decreased to 126 (0.78%). ^ According to the overall annual positive drug test incidence rates, the highest overall incidence was in 2002 (14.71 per 1000 tests) and the lowest in 2004 (3.17 per 1000 tests). Despite a marked increase in 2002, over the 15-year study period the overall incidence tended to decrease. Incidence rates and trends of other illegal drugs are further discussed in the study. And in general, these incidence rates also decline in the study period. In addition to that, we found the overall, positive drug tests were more common in females than in males (55.5% versus 44.4%). ^

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Cardiovascular disease has been the leading cause of death in the United States for over fifty years. While multiple risk factors for cardiovascular disease have been identified, hypertension is one of the most commonly recognized and treatable. Recent studies indicate that the prevalence of hypertension among children and adolescents is between 3-5%, much higher than originally estimated and likely rising due to the epidemic of obesity in the U.S. In 2004, the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents published new guidelines for the diagnosis and treatment of hypertension in this population. Included in these recommendations was the creation of a new diagnosis, pre-hypertension, aimed at identifying children at-risk for hypertension to provide early lifestyle interventions in an effort to prevent its ultimate development. In order to determine the risk associated with pre-hypertension for the development of incident HTN, a secondary analysis of a repeated cross-sectional study measuring blood pressure in Houston area adolescents from 2000 to 2007 was performed. Of 1006 students participating in the blood pressure screening on more than one occasion not diagnosed with hypertension at initial encounter, eleven were later found to have hypertension providing an overall incident rate of 0.5% per year. Incidence rates were higher among overweight adolescents–1.9% per year [IRR 8.6 (1.97, 51.63)]; students “at-risk for hypertension” (pre-hypertensive or initial blood pressure in the hypertensive range but falling on subsequent measures)–1.4% per year [IRR 4.77 (1.21, 19.78)]; and those with blood pressure ≥90th percentile on three occasions–6.6% per year [IRR 21.87 (3.40, 112.40)]. Students with pre-hypertension as currently defined by the Task Force did have an increased rate of hypertension (1.1% per year) but it did not reach statistical significance [IRR 2.44 (0.42, 10.18)]. Further research is needed to determine the morbidity and mortality associated with pre-hypertension in this age group as well as the effectiveness of various interventions for preventing the development of hypertensive disease among these at-risk individuals. ^

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Background. Cardiac risk assessment in cancer patients has not extensively been studied. We evaluated the role of stress myocardial perfusion imaging (MPI) in predicting cardiovascular outcomes in cancer patients undergoing non-cardiac surgery. ^ Methods. A retrospective chart review was performed on 507 patients who had a MPI from 01/2002 - 03/2003 and underwent non-cardiac surgery. Median follow-up duration was 1.5 years. Cox proportional hazard model was used to determine the time-to-first event. End points included total cardiac events (cardiac death, myocardial infarction (MI) and coronary revascularization), cardiac death, and all cause mortality. ^ Results. Of all 507 MPI studies 146 (29%) were abnormal. There were significant differences in risk factors between normal and abnormal MPI groups. Mean age was 66±11 years, with 60% males and a median follow-up duration of 1.8 years (25th quartile=0.8 years, 75th quartile=2.2 years). The majority of patients had an adenosine stress study (53%), with fewer exercise (28%) and dobutamine stress (16%) studies. In the total group there were 39 total cardiac events, 31 cardiac deaths, and 223 all cause mortality events during the study. Univariate predictors of total cardiac events included CAD (p=0.005), previous MI (p=0.005), use of beta blockers (p=0.002), and not receiving chemotherapy (p=0.012). Similarly, the univariate predictors of cardiac death included previous MI (p=0.019) and use of beta blockers (p=0.003). In the multivariate model for total cardiac events, age at surgery (HR 1.04, p=0.030), use of beta blockers (HR 2.46; p=0.011), dobutamine MPI (HR 3.08; p=0.018) and low EF (HR 0.97; p=0.02) were significant predictors of worse outcomes. In the multivariate model for predictors of cardiac death, beta blocker use (HR=2.74; p=0.017) and low EF (HR=0.95; p<0.003) were predictors of cardiac death. The only univariate MPI predictor of total cardiac events was scar severity (p=0.005). While MPI predictors of cardiac death were scar severity (p= 0.001) and ischemia severity (p=0.02). ^ Conclusions. Stress MPI is a useful tool in predicting long term outcomes in cancer patients undergoing surgery. Ejection fraction and severity of myocardial scar are important factors determining long term outcomes in this group.^

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The purpose of this dissertation research was to investigate potential mechanisms through which mutations in two ubiquitously expressed genes, inosine monophosphate dehydrogenase 1 (IMPDH1) and pre-mRNA processing factor 31 (PRPF31), cause autosomal dominant retinitis pigmentosa (adRP) but have no other apparent clinical consequences. Basic properties of the gene and gene product, such as expression and protein levels, were examined. The purpose of our research is to understand the genetic basis of inherited retinopathies such as retinitis pigmentosa (RP). RP is a heterogeneous retinal dystrophy that affects approximately one in 3,700 individuals, making it the most common heritable retinal degenerative disease worldwide. Currently, mutations in 35 genes are known to cause RP and additional loci have been mapped but the underlying gene is not yet known. Often the genes associated with RP are integral to the biological processes underlying vision, making their role in retinal disease easy to explain. However, the mechanisms by which other genes cause RP are not apparent, especially widely-expressed genes. For IMPDH1, this research characterized the enzymatic properties of retinal isoforms. Results show that the retinal isoforms have enzymatic functions similar to the previously known canonical IMPDH1 whether or not an adRP pigmentosa mutation is included in the protein. For PRPF31, this research tested the hypothesis that functional haploinsufficiency is the cause of disease and relates to nonpenetrance in some individuals. Studies in patients with known mutations show that haploinsufficiency is the likely cause of disease, however, we did not confirm that non-penetrant individuals are protected from disease via increased expression of the wild type allele. Information gleaned from these functional studies, and the testing methods developed in tandem, will contribute to future research on disease mechanism related to adRP. ^

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Many mental disorders disrupt social skills, yet few studies have examined how the brain processes social information. Functional neuroimaging, neuroconnectivity and electrophysiological studies suggest that orbital frontal cortex plays important roles in social cognition, including the analysis of information from faces, which are important cues in social interactions. Studies in humans and non-human primates show that damage to orbital frontal cortex produces social behavior impairments, including abnormal aggression, but these studies have failed to determine whether damage to this area impairs face processing. In addition, it is not known whether damage early in life is more detrimental than damage in adulthood. This study examined whether orbital frontal cortex is necessary for the discrimination of face identity and facial expressions, and for appropriate behavioral responses to aggressive (threatening) facial expressions. Rhesus monkeys (Macaca mulatta) received selective lesions of orbital frontal cortex as newborns or adults. As adults, these animals were compared with sham-operated controls on their ability to discriminate between faces of individual monkeys and between different facial expressions of emotion. A passive visual paired-comparison task with standardized rhesus monkey face stimuli was designed and used to assess discrimination. In addition, looking behavior toward aggressive expressions was assessed and compared with that of normal control animals. The results showed that lesion of orbital frontal cortex (1) may impair discrimination between faces of individual monkeys, (2) does not impair facial expression discrimination, and (3) changes the amount of time spent looking at aggressive (threatening) facial expressions depending on the context. The effects of early and late lesions did not differ. Thus, orbital frontal cortex appears to be part of the neural circuitry for recognizing individuals and for modulating the response to aggression in faces, and the plasticity of the immature brain does not allow for recovery of these functions when the damage occurs early in life. This study opens new avenues for the assessment of rhesus monkey face processing and the neural basis of social cognition, and allows a better understanding of the nature of the neuropathology in patients with mental disorders that disrupt social behavior, such as autism. ^

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The Centers for Disease Control estimates that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. The American public is becoming more health conscious and there has been an increase in the dietary intake of fresh fruits and vegetables. Affluence and demand for convenience has allowed consumers to opt for pre-processed packaged fresh fruits and vegetables. These pre-processed foods are considered Ready-to-Eat. They have many of the advantages of fresh produce without the inconvenience of processing at home. After seeing a decline in food-related illnesses between 1996 and 2004, due to an improvement in meat and poultry safety, tainted produce has tilted the numbers back. This has resulted in none of the Healthy People 2010 targets for food-related illness reduction being reached. Irradiation has been shown to be effective in eliminating many of the foodborne pathogens. The application of irradiation as a food safety treatment has been widely endorsed by many of the major associations involved with food safety and public health. Despite these endorsements there has been very little use of this technology to date for reducing the disease burden associated with the consumption of these products. A review of the available literature since the passage of the 1996 Food Quality Protection Act was conducted on the barriers to implementing irradiation as a food safety process for fresh fruits and vegetables. The impediments to adopting widespread utilization of irradiation food processing as a food safety measure involve a complex array of legislative, regulatory, industry, and consumer issues. The FDA’s approval process limits the expansion of the list of foods approved for the application of irradiation as a food safety process. There is also a lack of capacity within the industry to meet the needs of a geographically dispersed industry.^

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High prevalence of overweight and obesity among preschool children in the low income population is consistently documented in research with one of every seven low-income, preschool-aged children classified as obese. Parental feeding practices have the potential to be contributing factors to the obesity epidemic. However, the impact of parental feeding practices on obesity in preschool age children has not been well explored. The purpose of this study was to determine relationships between the parental feeding practices of using dessert, sweets or candy as a reward for finishing foods, restricting dessert if the child does not finish their plate at dinner, asking the child to consume everything on their plate at dinner, and having family dinners to obesity in low income, preschool age children.^ A cross-sectional secondary data analysis was completed using the STATA 11 statistical software. Descriptive statistics were completed to summarize demographic and BMI data of participants, as well as parental feeding behavior variables. Pearson’s correlation was implemented to determine a correlation between parental feeding behavior variables and BMI z scores. Predictive relationships between the variables were explored through multivariable linear regression analysis. Regression analyses were also completed factoring in the confounders of gender, age, and ethnicity.^ Results revealed (1) no significant correlations or predictive trends between the use of rewards, forced consumption, or family dinner and BMI in low income preschool age children, and (2) a significant negative correlation and predictive trend between restriction of desserts and BMI in low income preschool age children. Since the analysis supported the null hypothesis for the practices of reward use, forced consumption, and family dinner, these practices are not considered risk factors for obese level BMIs. The inverse association found for practice of restriction and BMI suggests it is unnecessary to discourage parents from using restriction. Limitations of the study included the sample size, reliability of the answers provided on the Healthy Home Survey by participant guardians, and generalizability of the sample to the larger population.^

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Identifying accurate numbers of soldiers determined to be medically not ready after completing soldier readiness processing may help inform Army leadership about ongoing pressures on the military involved in long conflict with regular deployment. In Army soldiers screened using the SRP checklist for deployment, what is the prevalence of soldiers determined to be medically not ready? Study group. 15,289 soldiers screened at all 25 Army deployment platform sites with the eSRP checklist over a 4-month period (June 20, 2009 to October 20, 2009). The data included for analysis included age, rank, component, gender and final deployment medical readiness status from MEDPROS database. Methods.^ This information was compiled and univariate analysis using chi-square was conducted for each of the key variables by medical readiness status. Results. Descriptive epidemiology Of the total sample 1548 (9.7%) were female and 14319 (90.2%) were male. Enlisted soldiers made up 13,543 (88.6%) of the sample and officers 1,746 (11.4%). In the sample, 1533 (10.0%) were soldiers over the age of 40 and 13756 (90.0%) were age 18-40. Reserve, National Guard and Active Duty made up 1,931 (12.6%), 2,942 (19.2%) and 10,416 (68.1%) respectively. Univariate analysis. Overall 1226 (8.0%) of the soldiers screened were determined to be medically not ready for deployment. Biggest predictive factor was female gender OR (2.8; 2.57-3.28) p<0.001. Followed by enlisted rank OR (2.01; 1.60-2.53) p<0.001. Reserve component OR (1.33; 1.16-1.53) p<0.001 and Guard OR (0.37; 0.30-0.46) p<0.001. For age > 40 demonstrated OR (1.2; 1.09-1.50) p<0.003. Overall the results underscore there may be key demographic groups relating to medical readiness that can be targeted with programs and funding to improve overall military medical readiness.^