380 research outputs found
Thrombotic gene polymorphisms and postoperative outcome after coronary artery bypass graft surgery
<p>Abstract</p> <p>Background</p> <p>Emerging perioperative genomics may influence the direction of risk assessment and surgical strategies in cardiac surgery. The aim of this study was to investigate whether single nucleotide polymorphisms (SNP) affect the clinical presentation and predispose to increased risk for postoperative adverse events in patients undergoing coronary artery bypass grafting surgery (CABG).</p> <p>Methods</p> <p>A total of 220 patients undergoing first-time CABG between January 2005 and May 2008 were screened for factor V gene G1691A (FVL), prothrombin/factor II G20210A (PT G20210A), angiotensin I-converting enzyme insertion/deletion (ACE-ins/del) polymorphisms by PCR and Real Time PCR. End points were defined as death, myocardial infarction, stroke, postoperative bleeding, respiratory and renal insufficiency and event-free survival. Patients were compared to assess for any independent association between genotypes for thrombosis and postoperative phenotypes.</p> <p>Results</p> <p>Among 220 patients, the prevalence of the heterozygous FVL mutation was 10.9% (n = 24), and 3.6% (n = 8) were heterozygous carriers of the PT G20210A mutation. Genotype distribution of ACE-ins/del was 16.6%, 51.9%, and 31.5% in genotypes I/I, I/D, and D/D, respectively. FVL and PT G20210A mutations were associated with higher prevalence of totally occluded coronary arteries (p < 0.001). Furthermore the risk of left ventricular aneurysm formation was significantly higher in FVL heterozygote group compared to FVL G1691G (<it>p </it>= 0.002). ACE D/D genotype was associated with hypertension (<it>p </it>= 0.004), peripheral vascular disease (p = 0.006), and previous myocardial infarction (<it>p </it>= 0.007).</p> <p>Conclusions</p> <p>FVL and PT G20210A genotypes had a higher prevalence of totally occluded vessels potentially as a result of atherothrombotic events. However, none of the genotypes investigated were independently associated with mortality.</p
Statistical practices of educational researchers: An analysis of their ANOVA, MANOVA, and ANCOVA analyses
Articles published in several prominent educational journals were examined to investigate the use of data-analysis tools by researchers in four research paradigms: between-subjects univariate designs, between-subjects multivariate designs, repeated measures designs, and covariance designs. In addition to examining specific details pertaining to the research design (e.g., sample size, group size equality/inequality) and methods employed for data analysis, we also catalogued whether: (a) validity assumptions were examined, (b) effect size indices were reported, (c) sample sizes were selected based on power considerations, and (d) appropriate textbooks and/or articles were cited to communicate the nature of the analyses that were performed. Our analyses imply that researchers rarely verify that validity assumptions are satisfied and accordingly typically use analyses that are nonrobust to assumption violations. In addition, researchers rarely report effect size statistics, nor do they routinely perform power analyses to determine sample size requirements. We offer many recommendations to rectify these shortcomings.Social Sciences and Humanities Research Counci
Identification of Methylated Genes Associated with Aggressive Bladder Cancer
Approximately 500,000 individuals diagnosed with bladder cancer in the U.S. require routine cystoscopic follow-up to monitor for disease recurrences or progression, resulting in over $2 billion in annual expenditures. Identification of new diagnostic and monitoring strategies are clearly needed, and markers related to DNA methylation alterations hold great promise due to their stability, objective measurement, and known associations with the disease and with its clinical features. To identify novel epigenetic markers of aggressive bladder cancer, we utilized a high-throughput DNA methylation bead-array in two distinct population-based series of incident bladder cancer (n = 73 and n = 264, respectively). We then validated the association between methylation of these candidate loci with tumor grade in a third population (n = 245) through bisulfite pyrosequencing of candidate loci. Array based analyses identified 5 loci for further confirmation with bisulfite pyrosequencing. We identified and confirmed that increased promoter methylation of HOXB2 is significantly and independently associated with invasive bladder cancer and methylation of HOXB2, KRT13 and FRZB together significantly predict high-grade non-invasive disease. Methylation of these genes may be useful as clinical markers of the disease and may point to genes and pathways worthy of additional examination as novel targets for therapeutic treatment
Splenic size after division of the short gastric vessels in Nissen fundoplication in children
Item does not contain fulltextPURPOSE: Nissen fundoplication is an effective treatment for gastro-esophageal reflux disease (GERD). Mobilization of the gastric fundus during fundoplication requires division of short gastric vessels of the spleen, which may cause splenic ischemia. The aim of this study was to determine if Nissen fundoplication results in hypotrophy of the spleen. METHODS: We performed pre-operative and post-operative ultrasound measurements of the spleen in children undergoing Nissen fundoplication. During operation, the surgeon estimated the compromised blood flow by assessment of the percentage of discoloration of the spleen. RESULTS: Twenty-four consecutive children were analyzed. Discoloration of the upper pole of the spleen was observed in 11 patients (48%) of a median estimated splenic surface of 20% (range 5-50%). The median ratio for pre-operative and post-operative length, width, and area of the spleen was 0.97, 1.03, and 0.96, respectively. The percentage of the estimated perfusion defect during surgery was not correlated with the ratios. In three patients, the area ratio was smaller than 0.8 (0.67-0.75), meaning that the area decreased with at least 20% after surgery. In none of these patients a discoloration was observed. CONCLUSION: Discoloration of the spleen after Nissen fundoplication is not associated with post-operative splenic atrophy.1 maart 201
The Cosmological Baryon Density from the Deuterium Abundance at a redshift z = 3.57
We present a measurement of the deuterium to hydrogen ratio in a quasar
absorption system at redshift z = 3.57 towards QSO 1937-1009. We use a two
component fit, with redshifts determined from unsaturated metal lines, to fit
the hydrogen and deuterium features simultaneously. We find a low value of D/H
= 2.3 \pm 0.6 \times 10^{-5}, which does not agree with other measurements of
high D/H (Songaila et al. 1994, Carswell et al. 1994). The absorption system is
very metal poor, with metallicities less than 1/100 solar. Standard models of
chemical evolution show the astration of deuterium is limited to a few percent
from primordial for systems this metal-poor, so we believe our value represents
the primordial one. Using predictions of standard big-bang nucleosynthesis and
measurements of the cosmic microwave background, our measurement gives the
density of baryons in units of the critical density, , where H_0 = 100 h km s^{-1] Mpc^{-1}.Comment: 10 pages, 2 Figures, also available at http://nately.ucsd.edu/ ;
submitted to Natur
Specific and individuated death reflection fosters identity integration
Identity integration is the process wherein a person assimilates multiple or conflicting identities (e.g., beliefs, values, needs) into a coherent, unified self-concept. Three experiments examined whether contemplating mortality in a specific and individuated manner (i.e., via the death reflection manipulation) facilitated outcomes indicative of identity integration. Participants in the death reflection condition (vs. control conditions) considered positive and negative life experiences as equally important in shaping their current identity (Experiment 1), regarded self-serving values and other-serving values as equally important life principles (Experiment 2), and were equally motivated to pursue growth-oriented and security-oriented needs (Experiment 3). Death reflection motivates individuals to integrate conflicting aspects of their identity into a coherent self-concept. Given that identity integration is associated with higher well-being, the findings have implications for understanding the psychological benefits of existential contemplation
Frontal GABA Levels Change during Working Memory
Functional neuroimaging metrics are thought to reflect changes in neurotransmitter flux, but changes in neurotransmitter levels have not been demonstrated in humans during a cognitive task, and the relationship between neurotransmitter dynamics and hemodynamic activity during cognition has not yet been established. We evaluate the concentration of the major inhibitory (GABA) and excitatory (glutamate + glutamine: Glx) neurotransmitters and the cerebral perfusion at rest and during a prolonged delayed match-to-sample working memory task. Resting GABA levels in the dorsolateral prefrontal cortex correlated positively with the resting perfusion and inversely with the change in perfusion during the task. Further, only GABA increased significantly during the first working memory run and then decreased continuously across subsequent task runs. The decrease of GABA over time was paralleled by a trend towards decreased reaction times and higher task accuracy. These results demonstrate a link between neurotransmitter dynamics and hemodynamic activity during working memory, indicating that functional neuroimaging metrics depend on the balance of excitation and inhibition required for cognitive processing
A biophysical model of dynamic balancing of excitation and inhibition in fast oscillatory large-scale networks
Over long timescales, neuronal dynamics can be robust to quite large perturbations, such as changes in white matter connectivity and grey matter structure through processes including learning, aging, development and certain disease processes. One possible explanation is that robust dynamics are facilitated by homeostatic mechanisms that can dynamically rebalance brain networks. In this study, we simulate a cortical brain network using the Wilson-Cowan neural mass model with conduction delays and noise, and use inhibitory synaptic plasticity (ISP) to dynamically achieve a spatially local balance between excitation and inhibition. Using MEG data from 55 subjects we find that ISP enables us to simultaneously achieve high correlation with multiple measures of functional connectivity, including amplitude envelope correlation and phase locking. Further, we find that ISP successfully achieves local E/I balance, and can consistently predict the functional connectivity computed from real MEG data, for a much wider range of model parameters than is possible with a model without ISP
A simulation model approach to analysis of the business case for eliminating health care disparities
<p>Abstract</p> <p>Background</p> <p>Purchasers can play an important role in eliminating racial and ethnic disparities in health care. A need exists to develop a compelling "business case" from the employer perspective to put, and keep, the issue of racial/ethnic disparities in health care on the quality improvement agenda for health plans and providers.</p> <p>Methods</p> <p>To illustrate a method for calculating an employer business case for disparity reduction and to compare the business case in two clinical areas, we conducted analyses of the direct (medical care costs paid by employers) and indirect (absenteeism, productivity) effects of eliminating known racial/ethnic disparities in mammography screening and appropriate medication use for patients with asthma. We used Markov simulation models to estimate the consequences, for defined populations of African-American employees or health plan members, of a 10% increase in HEDIS mammography rates or a 10% increase in appropriate medication use among either adults or children/adolescents with asthma.</p> <p>Results</p> <p>The savings per employed African-American woman aged 50-65 associated with a 10% increase in HEDIS mammography rate, from direct medical expenses and indirect costs (absenteeism, productivity) combined, was 1,660 per person if raising medication adherence rates in African-American employees or dependents by 10%.</p> <p>Conclusions</p> <p>For the employer business case, both clinical scenarios modeled showed positive results. There is a greater potential financial gain related to eliminating a disparity in asthma medications than there is for eliminating a disparity in mammography rates.</p
Outcome after acute ischemic stroke is linked to sex-specific lesion patterns
Acute ischemic stroke affects men and women differently. In particular, women are often reported to experience higher acute stroke severity than men. We derived a low-dimensional representation of anatomical stroke lesions and designed a Bayesian hierarchical modeling framework tailored to estimate possible sex differences in lesion patterns linked to acute stroke severity (National Institute of Health Stroke Scale). This framework was developed in 555 patients (38% female). Findings were validated in an independent cohort (n = 503, 41% female). Here, we show brain lesions in regions subserving motor and language functions help explain stroke severity in both men and women, however more widespread lesion patterns are relevant in female patients. Higher stroke severity in women, but not men, is associated with left hemisphere lesions in the vicinity of the posterior circulation. Our results suggest there are sex-specific functional cerebral asymmetries that may be important for future investigations of sex-stratified approaches to management of acute ischemic stroke
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