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Find video protocols related to scientific articles indexed in Pubmed.
Neighborhood Factors Associated with Time to Resolution Following an Abnormal Breast or Cervical Cancer Screening Test.
Cancer Epidemiol. Biomarkers Prev.
PUBLISHED: 09-09-2014
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The effect of neighborhood and healthcare access factors on cancer outcomes among patients enrolled in navigator programs is not clearly understood. This study assessed associations between: (i) neighborhood factors and diagnostic time to resolution (TTR) and (ii) geographic access and TTR following an abnormal breast or cervical cancer screening test among women participating in the Ohio Patient Navigator Research Program (OPNRP).
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How are previous physical activity and self-efficacy related to future physical activity and self-efficacy?
Health Educ Behav
PUBLISHED: 08-25-2014
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Self-efficacy (SE) has been found to be a robust predictor of success in achieving physical activity (PA) goals. While much of the current research has focused on SE as a trait, SE as a state has received less attention. Using day-to-day measurements obtained over 84 days, we examined the relationship between state SE and PA. Postmenopausal women (n = 71) participated in a 12-week PA intervention administered via cell phone and monitored their daily PA using a pedometer. At the end of each day, they reported their state SE and number of steps. Using a longitudinal model, state SE was found to be a robust predictor of PA even after accounting for trait SE and other covariates. The findings offer insights about the temporal relationship between SE and PA over the course of an intervention, which can be of interest to researchers and intervention designers.
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Short and Long-term Effects of Ambient Ozone and Fine Particulate Matter on the Respiratory Health of COPD Subjects.
Arch Environ Occup Health
PUBLISHED: 08-19-2014
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Abstract To date, no study has evaluated the short and long-term effects air pollution exposure on emphysematous subjects who have undergone lung volume reduction surgery (LVRS). Data from the NETT study (1998-2003) included 1218 subjects, aged 39-84. Daily values of ambient fine particulate matter (PM2.5) and ozone were obtained. Mixed effects models tested the association between short and long-term pollutant concentrations and changes in pulmonary function. Cumulative air pollution exposure was strongly associated with worsened respiratory function and symptoms. Mean PM2.5 was associated with poorer lung function. Lagged exposures were poorly associated with respiratory health outcomes. There were detrimental respiratory and pulmonary effects observed in response to even low levels of ambient air pollutants among study participants. These results are indicative that exposures even below those of air quality standards may still pose significant risks to severe COPD subjects.
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Evaluating the Effect of Safety Culture on Error Reporting: A Comparison of Managerial and Staff Perspectives.
Am J Med Qual
PUBLISHED: 07-30-2014
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Although medical error reporting has been studied, underreporting remains pervasive. The study aims were to identify the organizational factors with the greatest perceived effect on error reporting and to determine whether associations differ for management and clinical staff. A total of 515 637 respondents from 1052 hospitals completed the Hospital Survey on Patient Safety Culture. Nine organizational factors were tested as predictors of error reporting using weighted least-squares multiple regression. Error feedback was perceived as the most significant predictor, while organizational learning was another significant factor. It also was found that although management support for patient safety was significantly related to error reporting among clinical staff, this association was not significant among management. This difference is relevant because managers may not be aware that their failure to demonstrate support for safety leads to underreporting by frontline clinical staff. Findings from this study can inform hospitals' efforts to increase error reporting.
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Ornstein-Uhlenbeck threshold regression for time-to-event data with and without a cure fraction.
Lifetime Data Anal
PUBLISHED: 07-23-2014
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In this paper we propose a threshold regression (TR) model for time to event data related to subject health using a latent Ornstein-Uhlenbeck (OU) process that fails once it hits a boundary value for the first time. Baseline covariates are incorporated into the analysis using a log-link function for the initial state of the health process. The model provides clinically meaningful covariate effects and does not require the proportional hazards assumption of the commonly used Cox model. Unlike TR models based on the Wiener process, the OU model allows increments in the health process to depend on previous values and drifts toward a state of equilibrium or homeostasis, which are present in many biological applications. We also extend our model to incorporate a cure rate for applications with improper survival functions, such as time to tumor recurrence in a cancer clinical trial. Our models are applied to overall and relapse-free survival data of melanoma patients undergoing definitive surgery.
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The influence of organizational factors on patient safety: Examining successful handoffs in health care.
Health Care Manage Rev
PUBLISHED: 07-17-2014
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Although patient handoffs have been extensively studied, they continue to be problematic. Studies have shown poor handoffs are associated with increased costs, morbidity, and mortality. No prior research compared perceptions of management and clinical staff regarding handoffs.
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Effect of a low-fat or low-carbohydrate weight-loss diet on markers of cardiovascular risk among premenopausal women: a randomized trial.
J Womens Health (Larchmt)
PUBLISHED: 07-16-2014
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Low-fat and low-carbohydrate weight-loss diets can have a beneficial effect on longitudinal measures of blood pressure and blood lipids. We aimed to assess longitudinal changes in blood pressure and blood lipids in a population of premenopausal women. We hypothesized that results may differ by level of adherence to the respective diet protocol and baseline presence of hypertension or hyperlipidemia.
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No association between colorectal cancer worry and screening uptake in Appalachian Ohio.
J Public Health (Oxf)
PUBLISHED: 05-23-2014
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Limited data are available on the association between colorectal cancer (CRC) worry and CRC screening uptake, particularly in rural and underserved populations where there is an excess burden of CRC.
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Trust in physicians among rural Medicaid-enrolled smokers.
J Rural Health
PUBLISHED: 04-03-2014
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Associations have been found between trusting patient-physician relationships and use of preventive care and a greater adherence to prescribed care. The objectives of this study were to assess the level of trust rural Medicaid smokers have in their physicians and whether trust was related to patient characteristics or physician behavior.
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Iron and noncontrast magnetic resonance T2* as a marker of intraplaque iron in human atherosclerosis.
J. Vasc. Surg.
PUBLISHED: 02-04-2014
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Iron has been implicated in atherogenesis and plaque destabilization, whereas less is known about iron-related proteins in this disease. We compared ex vivo quantities with in vivo vessel wall T2*, which is a noncontrast magnetic resonance relaxation time that quantitatively shortens with increased tissue iron content. We also tested the hypothesis that patients with carotid atherosclerosis have abnormal T2* times vs controls that would help support a role for iron in human atherosclerosis.
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Provider-delivered tobacco dependence treatment to medicaid smokers.
Nicotine Tob. Res.
PUBLISHED: 01-28-2014
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Smoking prevalence is 49% among Medicaid enrollees in Ohio. The objective of this pilot project was to test a comprehensive tobacco dependence treatment program targeting rural Medicaid-enrolled smokers for both physician-level and smoker-level outcomes.
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Effects of a walking intervention using mobile technology and interactive voice response on serum adipokines among postmenopausal women at increased breast cancer risk.
Horm Cancer
PUBLISHED: 01-17-2014
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Practical methods to reduce the risk of obesity-related breast cancer among high-risk subgroups are lacking. Few studies have investigated the effects of exercise on circulating adipokines, which have been shown to be associated with obesity and breast cancer. The aim of this study was to examine the effects of a walking intervention on serum adiponectin, leptin, and the adiponectin-to-leptin ratio (A/L). Seventy-one overweight and obese postmenopausal women at increased risk of developing breast cancer were stratified by BMI (25-30 kg/m(2) or >30 kg/m(2)) and randomized to a 12-week, two-arm walking intervention administered through interactive voice response (IVR) and mobile devices. The intervention arms were IVR + coach and IVR + no-coach condition. Pre-post changes in serum adiponectin, leptin, and the A/L ratio were examined using mixed regression models, with ratio estimates (and 95 % confidence intervals [CI]) corresponding to postintervention adipokine concentrations relative to preintervention concentrations. While postintervention effects included statistically significant improvements in anthropometric measures, the observed decreases in adiponectin and leptin (ratio = 0.86, 95 % CI 0.74-1.01, and ratio = 0.94, 95 % CI 0.87-1.01, respectively) and increase in A/L ratio = 1.09, 95 % CI 0.94-1.26) were not significant. Thus, these findings do not support significant effects of the walking intervention on circulating adipokines among overweight and obese postmenopausal women. Additional studies are essential to determine the most effective and practical lifestyle interventions that can promote beneficial modification of serum adipokine concentrations, which may prove useful for obesity-related breast cancer prevention.
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Favorable effects of low-fat and low-carbohydrate dietary patterns on serum leptin, but not adiponectin, among overweight and obese premenopausal women: a randomized trial.
Springerplus
PUBLISHED: 01-01-2014
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The most effective dietary pattern for breast cancer prevention has been greatly debated in recent years. Studies have examined hypocaloric diets, with particular emphasis on macronutrient composition, yielding inconclusive data. The objective of this study was to examine the effects of calorie-restricted low-fat and low-carbohydrate diets (LFD and LCD, respectively) on circulating adipokines among overweight and obese premenopausal women.
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Preclinical evaluation of the novel, orally bioavailable Selective Inhibitor of Nuclear Export (SINE) KPT-335 in spontaneous canine cancer: results of a phase I study.
PLoS ONE
PUBLISHED: 01-01-2014
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The purpose of this study was to evaluate the activity of Selective Inhibitors of Nuclear Export (SINE) compounds that inhibit the function of the nuclear export protein Exportin 1 (XPO1/CRM1) against canine tumor cell lines and perform a Phase I clinical trial of KPT-335 in dogs with spontaneous cancer to provide a preliminary assessment of biologic activity and tolerability.
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Effects of tomato and soy on serum adipokine concentrations in postmenopausal women at increased breast cancer risk: a cross-over dietary intervention trial.
J. Clin. Endocrinol. Metab.
PUBLISHED: 01-01-2014
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Breast cancer risk among postmenopausal women increases as body mass index increases. Practical preventive methods to reduce risk of breast cancer are lacking. Few studies have investigated the effects of carotenoids and isoflavones on circulating adipokines in postmenopausal women.
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The choice of reference gene affects statistical efficiency in quantitative PCR data analysis.
BioTechniques
PUBLISHED: 08-12-2013
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Quantitative polymerase chain reaction (qPCR), a highly sensitive method of measuring gene expression, is widely used in biomedical research. To produce reliable results, it is essential to use stably expressed reference genes (RGs) for data normalization so that sample-to-sample variation can be controlled. In this study, we examine the effect of different RGs on statistical efficiency by analyzing a qPCR data set that contains 12 target genes and 3 RGs. Our results show that choosing the most stably expressed RG for data normalization does not guarantee reduced variance or improved statistical efficiency. We also provide a formula for determining when data normalization will improve statistical efficiency and hence increase the power of statistical tests in data analysis.
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Comparison of treadmill exercise stress cardiac MRI to stress echocardiography in healthy volunteers for adequacy of left ventricular endocardial wall visualization: A pilot study.
J Magn Reson Imaging
PUBLISHED: 05-16-2013
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To compare exercise stress cardiac magnetic resonance (cardiac MR) to echocardiography in healthy volunteers with respect to adequacy of endocardial visualization and confidence of stress study interpretation.
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Evaluation of the adverse event profile and pharmacodynamics of toceranib phosphate administered to dogs with solid tumors at doses below the maximum tolerated dose.
BMC Vet. Res.
PUBLISHED: 04-28-2013
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The receptor kinase inhibitor toceranib phosphate (Palladia) was approved for use in dogs in 2009 using a dose of 3.25 mg/kg administered every other day. Preliminary data suggests that lower doses of toeceranib may be associated with a reduced adverse event profile while maintaining sufficient drug exposure to provide biologic activity. The purpose of this study was to determine the Cmax of toceranib in dogs with solid tumors receiving 2.5-2.75 mg/kg every other day and to document the adverse events associated with this dose rate. Secondary objectives included determination of plasma VEGF concentrations in treated dogs and response to therapy.
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Correlates of colorectal cancer screening among residents of Ohio Appalachia.
J Community Health
PUBLISHED: 03-27-2013
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There is an excess burden of colorectal cancer (CRC) in the Appalachian region of the United States, which could be reduced by increased uptake of CRC screening tests. Thus, we examined correlates of screening among Appalachian residents at average-risk for CRC. Using a population-based sample, we conducted interviews with and obtained medical records of Appalachian Ohio residents 51-75 years between September 2009 and April 2010. Using multivariable logistic regression, we identified correlates of being within CRC screening guidelines by medical records. About half of participants were within CRC screening guidelines. Participants who were older (OR = 1.04, 95 % CI 1.01, 1.07), had higher income ($30,000-$60,000, OR = 1.92, 95 % CI 1.29, 2.86; ?$60,000, OR = 1.80, 95 % CI 1.19, 2.72), a primary care provider (OR = 4.22, 95 % CI 1.33, 13.39), a recent check-up (OR = 2.37, 95 % CI 1.12, 4.99), had been encouraged to be screened (OR = 1.57, 95 % CI 1.11, 2.22), had been recommended by their doctor to be screened (OR = 6.68, 95 % CI 3.87, 11.52), or asked their doctor to order a screening test (OR = 2.24, 95 % CI 1.36, 3.69) had higher odds of being screened within guidelines in multivariable analysis. Findings suggest that access to and utilization of healthcare services, social influence, and patient-provider communication were the major factors associated with CRC screening. Researchers and healthcare providers should develop and implement strategies targeting these barriers/facilitators to improve CRC screening rates and reduce the CRC burden among residents of Appalachia.
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Nonoutbreak-related airborne Staphylococcus spp in a veterinary hospital.
Am J Infect Control
PUBLISHED: 01-12-2013
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Methicillin-resistant Staphylococcus spp (MRS), such as methicillin-resistant Staphylococcus aureus (MRSA), is a nosocomial pathogen of significant concern. This study evaluates the prevalence and determinants of airborne MRS and methicillin-susceptible Staphylococcus spp (MSS) in a veterinary teaching hospital during periods of no known active clinical cases of Staphylococci infections.
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Enhancing cancer screening in primary care: rationale, design, analysis plan, and recruitment results.
Contemp Clin Trials
PUBLISHED: 01-10-2013
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Colorectal cancer (CRC) is the third leading type of cancer and the third leading cause of cancer death in the United States. National policy-making organizations recognize and support a variety of CRC screening strategies among average-risk adults aged 50 and older based on strong evidence showing that screening decreases mortality from CRC and can also reduce the incidence of the disease. The goal of this study was to test a multi-level stepped intervention to increase CRC screening rates. We used a group-randomized trial design where the units of assignment were clinics and the units of observation were eligible patients receiving care at those clinics, with stratified random assignment of clinics to study conditions. The primary analysis was planned as a mixed-model logistic regression to account for the expected positive intraclass correlation associated with clinics. Our recruitment experience reflected the difficulties of conducting research in the real world where changes in economic conditions, staff turnover/layoff, inadequate medical records, and poor acceptance of research can significantly impact study plans. It demonstrated the problems that can emerge when procedures used in the study depart from those used in the pilot work to generate parameter estimates for power analysis. It also demonstrated the importance of allowing for attrition at the group and patient levels so that if recruitment falls short, it is possible to maintain adequate power with only a slight increase in the detectable difference. This experience should assist others planning group-randomized trials, whether in cancer screening or in other areas.
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Semiparametric Bayesian joint modeling of a binary and continuous outcome with applications in toxicological risk assessment.
Stat Med
PUBLISHED: 01-07-2013
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Many dose-response studies collect data on correlated outcomes. For example, in developmental toxicity studies, uterine weight and presence of malformed pups are measured on the same dam. Joint modeling can result in more efficient inferences than independent models for each outcome. Most methods for joint modeling assume standard parametric response distributions. However, in toxicity studies, it is possible that response distributions vary in location and shape with dose, which may not be easily captured by standard models. To address this issue, we propose a semiparametric Bayesian joint model for a binary and continuous response. In our model, a kernel stick-breaking process prior is assigned to the distribution of a random effect shared across outcomes, which allows flexible changes in distribution shape with dose shared across outcomes. The model also includes outcome-specific fixed effects to allow different location effects. In simulation studies, we found that the proposed model provides accurate estimates of toxicological risk when the data do not satisfy assumptions of standard parametric models. We apply our method to data from a developmental toxicity study of ethylene glycol diethyl ether. Copyright © 2013 John Wiley & Sons, Ltd.
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A walking intervention for postmenopausal women using mobile phones and Interactive Voice Response.
J Telemed Telecare
PUBLISHED: 11-03-2011
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We conducted a feasibility study of a 12-week walking intervention administered through an Interactive Voice Response (IVR) system and mobile phones. We also examined the added benefit of a human coach. Post-menopausal women (n = 71) were given a daily-steps goal, which they monitored using a pedometer. Each day, they answered an automated call from the IVR system to their mobile phone and provided assessments of walking goals and mood. Every evening, they called the IVR system to report their steps, answered a brief questionnaire and received a message with a helpful hint. Participants took less time to complete a one-mile walk after the intervention, compared to baseline (0.77 min, SE = 0.22, P < 0.001). In addition, a significant loss in body weight (0.93 kg, SE = 0.31) and body-mass index (0.28 kg/m(2), SE = 0.11) were observed. The key psychometric measures of exercise goal setting (0.67 units, SE = 0.12) and exercise planning (0.48 units, SE = 0.09) also improved from baseline (both P < 0.001). However, results in the coach and no-coach conditions were not significantly different. The study suggests that mobile phones can be used to deliver an effective, low-cost walking intervention, irrespective of the addition of a human coach.
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Studies with staggered starts: multiple baseline designs and group-randomized trials.
Am J Public Health
PUBLISHED: 09-22-2011
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Multiple baseline designs (MBDs) have been suggested as alternatives to group-randomized trials (GRT). We reviewed structural features of MBDs and considered their potential effectiveness in public health research. We also reviewed the effect of staggered starts on statistical power.
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Design and Rationale for the Study of Changes in Iron and Atherosclerosis Risk in Perimenopause.
J Clin Exp Cardiolog
PUBLISHED: 08-25-2011
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This study seeks to investigate changes in iron homeostasis and carotid arteries in women at risk of atherosclerosis, addressing a relatively unexplored hypothesis explaining why women have a 5-10 year lag in initial atherosclerotic events. Recent evidence points to hepcidin, the key regulator of macrophage iron uptake and release, as a potential mediator of risk. Furthermore, iron catalyzes the generation of free radicals that oxidize cholesterol stimulating atheroma formation. Magnetic resonance imaging (MRI) is ideally suited to study iron because of irons local effects on magnetic susceptibility that can be quantified using a relaxation parameter called T2* (T2-star), as well as the ability to noninvasively characterize and quantify atherosclerotic plaque with MRI. This work outlines the rationale and study design to provide critical evidence related to the iron hypothesis, such that novel diagnostics and therapeutics to attenuate risk may be derived from a better understanding of irons role in atherosclerosis.
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Identification of impurities in artemisinin, their behavior in high performance liquid chromatography and implications for the quality of derived anti-malarial drugs.
J Chromatogr A
PUBLISHED: 05-30-2011
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Previous work [1] on the HPLC analysis of artemisinin tentatively identified the two impurities present above trace levels. This identification was based on LC-MS results and NMR of impurities isolated from artemisinin. In this work the impurities have been synthesized allowing verification of their identity by LC-MS. It is found that the previously suggested elution order is incorrect. A determination of relative response factors strongly impacts suggested limits on impurity levels and explains the erroneous peak assignment. The fates of the identified impurities are explored in the transformation of artemisinin to its derivative active pharmaceutical ingredients. A survey of a wide variety of artemisinin samples isolated from different geographical regions, different growing seasons, different plant backgrounds and using different extraction and purification approaches showed that artemisinin has sufficient purity for its intended use as a raw material for anti-malarial drug products.
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Shared velocity encoding: a method to improve the temporal resolution of phase-contrast velocity measurements.
Magn Reson Med
PUBLISHED: 05-03-2011
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Phase-contrast magnetic resonance imaging (PC-MRI) is used routinely to measure fluid and tissue velocity with a variety of clinical applications. Phase-contrast magnetic resonance imaging methods require acquisition of additional data to enable phase difference reconstruction, making real-time imaging problematic. Shared Velocity Encoding (SVE), a method devised to improve the effective temporal resolution of phase-contrast magnetic resonance imaging, was implemented in a real-time pulse sequence with segmented echo planar readout. The effect of SVE on peak velocity measurement was investigated in computer simulation, and peak velocities and total flow were measured in a flow phantom and in volunteers and compared with a conventional ECG-triggered, segmented k-space phase-contrast sequence as a reference standard. Computer simulation showed a 36% reduction in peak velocity error from 8.8 to 5.6% with SVE. A similar reduction of 40% in peak velocity error was shown in a pulsatile flow phantom. In the phantom and volunteers, volume flow did not differ significantly when measured with or without SVE. Peak velocity measurements made in the volunteers using SVE showed a higher concordance correlation (0.96) with the reference standard than non-SVE (0.87). The improvement in effective temporal resolution with SVE reconstruction has a positive impact on the precision and accuracy of real-time phase-contrast magnetic resonance imaging peak velocity measurements.
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Oncostatin M promotes STAT3 activation, VEGF production, and invasion in osteosarcoma cell lines.
BMC Cancer
PUBLISHED: 04-11-2011
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We have previously demonstrated that both canine and human OSA cell lines, as well as 8 fresh canine OSA tumor samples, exhibit constitutive phosphorylation of STAT3, and that this correlates with enhanced expression of matrix metalloproteinase-2 (MMP2). While multiple signal transduction pathways can result in phosphorylation of STAT3, stimulation of the cytokine receptor gp130 through either IL-6 or Oncostatin M (OSM) is the most common mechanism through which STAT3 is activated. The purpose of this study was to evaluate the role of IL-6 and OSM stimulation on both canine and human OSA cell lines to begin to determine the role of these cytokines in the biology of OSA.
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Cutoff designs for community-based intervention studies.
Stat Med
PUBLISHED: 01-24-2011
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Public health interventions are often designed to target communities defined either geographically (e.g. cities, counties) or socially (e.g. schools or workplaces). The group randomized trial (GRT) is regarded as the gold standard for evaluating these interventions. However, community leaders may object to randomization as some groups may be denied a potentially beneficial intervention. Under a regression discontinuity design (RDD), individuals may be assigned to treatment based on the levels of a pretest measure, thereby allowing those most in need of the treatment to receive it. In this article, we consider analysis, power, and sample size issues in applying the RDD and related cutoff designs in community-based intervention studies. We examine the power of these designs as a function of intraclass correlation, number of groups, and number of members per group and compare results to the traditional GRT.
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Fully moderated T-statistic for small sample size gene expression arrays.
Stat Appl Genet Mol Biol
PUBLISHED: 01-01-2011
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Gene expression microarray experiments with few replications lead to great variability in estimates of gene variances. Several Bayesian methods have been developed to reduce this variability and to increase power. Thus far, moderated t methods assumed a constant coefficient of variation (CV) for the gene variances. We provide evidence against this assumption, and extend the method by allowing the CV to vary with gene expression. Our CV varying method, which we refer to as the fully moderated t-statistic, was compared to three other methods (ordinary t, and two moderated t predecessors). A simulation study and a familiar spike-in data set were used to assess the performance of the testing methods. The results showed that our CV varying method had higher power than the other three methods, identified a greater number of true positives in spike-in data, fit simulated data under varying assumptions very well, and in a real data set better identified higher expressing genes that were consistent with functional pathways associated with the experiments.
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Maternal docosahexaenoic acid supplementation decreases lung inflammation in hyperoxia-exposed newborn mice.
J. Nutr.
PUBLISHED: 12-22-2010
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DHA is a long-chain fatty acid that has potent antiinflammatory properties. Whereas maternal DHA dietary supplementation has been shown to improve cognitive development in infants fed DHA-supplemented milk, the antiinflammatory effects of maternal DHA supplementation on the developing fetus and neonate have not been extensively explored. Pregnant C3H/HeN dams were fed purified control or DHA-supplemented diets (~0.25% of total fat) at embryonic d 16 and consumed these diets throughout the study. At birth, the nursing mouse pups were placed in room air (RA; 21% O(2)) or >95% O(2) (hyperoxia) for up to 7 d. These studies tested the hypothesis that maternal DHA supplementation would decrease inflammation and improve alveolarization in the lungs of newborn mouse pups exposed to hyperoxia. Survival, inflammatory responses, and lung growth were compared among control diet/RA, DHA/RA, control/O(2), and DHA/O(2) pups. There were fewer neutrophils and macrophages in lung tissues from pups nursed by DHA-supplemented dams than in those nursed by dams fed the control diet at 7 d of hyperoxia exposure (P < 0.015). Although differences due to hyperoxia exposure were observed, maternal diet did not affect keratinocyte-derived chemokine, macrophage inflammatory protein-2, IL-1?, or TNF? mRNA levels in pup tissues. Hyperoxia also induced NF-?B activity, but maternal diet did not affect NF-?B or PPAR? activities. In mice, DHA supplementation decreases leukocyte infiltration in the offspring exposed to hyperoxia, suggesting a potential role for DHA supplementation as a therapy to reduce inflammation in preterm infants.
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Impaired myocardial perfusion reserve and fibrosis in Friedreich ataxia: a mitochondrial cardiomyopathy with metabolic syndrome.
Eur. Heart J.
PUBLISHED: 12-14-2010
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Cardiomyopathy produces significant mortality in patients with Friedreich ataxia (FA), a genetic disorder that produces intra-mitochondrial iron accumulation. We sought to test the hypothesis that abnormal myocardial perfusion reserve and fibrosis represent early manifestations of cardiomyopathy.
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Biological activity of gemcitabine against canine osteosarcoma cell lines in vitro.
Am. J. Vet. Res.
PUBLISHED: 07-03-2010
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To evaluate in vitro biological activity of gemcitabine, alone and in combination with Pamidronate or carboplatin, against canine osteosarcoma (OSA) cell lines.
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Using a simplified human immunodeficiency virus type 1 p24 antigen assay to diagnose pediatric HIV-infection in Malawi.
J. Clin. Virol.
PUBLISHED: 06-11-2010
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There is a worldwide need for a pediatric HIV-1 diagnostic test that has a high diagnostic accuracy, is technically simple and cost efficient. The Up24 HIV-1 assay, which requires both the HIV-1 p24 ELISA and the ELAST signal amplification kit, has previously been shown to be a robust tool to diagnose pediatric HIV-1 from dried whole blood spots (DBS) (Cachafeiro et al., JCM 2009;47:459-62(13)). In order to make the assay more accessible to a resource-limited clinical setting, we eliminated the ELAST system, which simplified the Up24 assay, reduced its cost, and tested the accuracy of the modified assay in a rural Malawian hospital.
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Computer-aided classification of centroblast cells in follicular lymphoma.
Anal. Quant. Cytol. Histol.
PUBLISHED: 06-01-2010
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To distinguish centroblast cells from non-centroblast cells using a novel automated method in follicular lymphoma cases and measure its performance on cases obtained by a consensus of six pathologists.
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Prenatal exposure to the major DDT metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and growth in boys from Mexico.
Environ. Res.
PUBLISHED: 05-19-2010
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Recent data suggest that prenatal exposure to p,p-DDE may reduce height and increase body mass index (BMI) in childhood, thus potentially raising the risk of adult health problems. The association between prenatal DDE exposure and growth was evaluated in 788 boys from Chiapas, an area of Mexico where DDT was recently used. The median DDE levels in maternal serum at birth (2002-2003) were 2.7 microg/g lipid. 2633 measurements of height (cm) and weight (kg) were obtained in 2004-2005. The median age of the children during follow-up was 18 months (quartiles 14 and 22 months). Height and body mass index (kg/m(2)) were age-standardized and expressed as standard deviation scores (SDS). Multivariate random-effect models for longitudinal data were fitted and predicted height and BMI SDS were estimated from the adjusted models. Overall, associations between prenatal DDE level and height or BMI SDS at any given age were not observed. For example, the predicted values showed that children with the highest exposure (DDE: >9.00 microg/g) compared to those least exposed (DDE: <3.01 microg/g) grew similarly and they had a BMI SDS similar to the referent group. The results do not support the prior findings of an association of DDE exposure with childhood height or BMI.
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Clean indoor air ordinance coverage in the Appalachian region of the United States.
Am J Public Health
PUBLISHED: 05-13-2010
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We sought to quantitatively examine the pattern of, and socioeconomic factors associated with, adoption of clean indoor air ordinances in Appalachia.
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Intraclass correlation estimates for cancer screening outcomes: estimates and applications in the design of group-randomized cancer screening studies.
J. Natl. Cancer Inst. Monographs
PUBLISHED: 04-14-2010
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Screening has become one of our best tools for early detection and prevention of cancer. The group-randomized trial is the most rigorous experimental design for evaluating multilevel interventions. However, identifying the proper sample size for a group-randomized trial requires reliable estimates of intraclass correlation (ICC) for screening outcomes, which are not available to researchers. We present crude and adjusted ICC estimates for cancer screening outcomes for various levels of aggregation (physician, clinic, and county) and provide an example of how these ICC estimates may be used in the design of a future trial.
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Designing studies that would address the multilayered nature of health care.
J. Natl. Cancer Inst. Monographs
PUBLISHED: 04-14-2010
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We review design and analytic methods available for multilevel interventions in cancer research with particular attention to study design, sample size requirements, and potential to provide statistical evidence for causal inference. The most appropriate methods will depend on the stage of development of the research and whether randomization is possible. Early on, fractional factorial designs may be used to screen intervention components, particularly when randomization of individuals is possible. Quasi-experimental designs, including time-series and multiple baseline designs, can be useful once the intervention is designed because they require few sites and can provide the preliminary evidence to plan efficacy studies. In efficacy and effectiveness studies, group-randomized trials are preferred when randomization is possible and regression discontinuity designs are preferred otherwise if assignment based on a quantitative score is possible. Quasi-experimental designs may be used, especially when combined with recent developments in analytic methods to reduce bias in effect estimates.
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Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT.
J Cardiovasc Magn Reson
PUBLISHED: 03-22-2010
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To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress.
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An automated method to segment the femur for osteoarthritis research.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 12-08-2009
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In this paper we develop a fully automated method for the segmentation of the femur in axial MR images and its use in the analysis of imaging biomarkers for osteoarthritis (OA). The proposed method is based on anatomical constraints implemented using morphological operations to extract the femur medulla and a level set evolution to extract the femur cortex. The average agreement of the automated segmentation algorithm with ground truth manual segmentations was 0.94 +/- 0.03 calculated using the Zijdenbos similarity index (ZSI). A pooled variance t-test analysis found significant associations between the KL grade, a clinical measure of OA severity, and both the cross-sectional area (CSA) of the femur medulla (p = 0.02) and the ratio of the femur medulla CSA to the femur cortex CSA (p = 0.04) for women. No significant association between femur measurements and KL grade was found for men.
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An automated method to detect interstitial adipose tissue in thigh muscles for patients with osteoarthritis.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 12-08-2009
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In this paper we explore a method of segmentation of muscle interstitial adipose tissue (IAT) in MR images of the thigh. The objective is to apply the method towards research into biomarkers of osteoarthritis (OA). T1-weighted images of the thigh are intensity standardized through bias field correction and intensity normalization. IAT within the thigh muscles is then segmented using a threshold combined with morphological constraints applied on connected regions in the thresholded image. The morphological constraints can be adjusted to allow for highly sensitive or highly specific IAT segmentation. The use of the morphological constraints improved the specificity of IAT segmentation over a threshold segmentation method from 0.54 to 0.67, while retaining a nearly equivalent sensitivity of 0.82 compared to 0.84. We then present a preliminary statistical analysis to demonstrate the application of the automated IAT segmentation. Finally, we specify a protocol for further exploration of IAT by leveraging the massive imaging dataset of the Osteoarthritis Initiative (OAI).
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Bayesian random-effects threshold regression with application to survival data with nonproportional hazards.
Biostatistics
PUBLISHED: 10-14-2009
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In epidemiological and clinical studies, time-to-event data often violate the assumptions of Cox regression due to the presence of time-dependent covariate effects and unmeasured risk factors. An alternative approach, which does not require proportional hazards, is to use a first hitting time model which treats a subjects health status as a latent stochastic process that fails when it reaches a threshold value. Although more flexible than Cox regression, existing methods do not account for unmeasured covariates in both the initial state and the rate of the process. To address this issue, we propose a Bayesian methodology that models an individuals health status as a Wiener process with subject-specific initial state and drift. Posterior inference proceeds via a Markov chain Monte Carlo methodology with data augmentation steps to sample the final health status of censored observations. We apply our method to data from melanoma patients with nonproportional hazards and find interesting differences from a similar model without random effects. In a simulation study, we show that failure to account for unmeasured covariates can lead to inaccurate estimates of survival probabilities.
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The Ohio Patient Navigation Research Program: does the American Cancer Society patient navigation model improve time to resolution in patients with abnormal screening tests?
Cancer Epidemiol. Biomarkers Prev.
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Patient navigation (PN) has been suggested as a way to reduce cancer health disparities; however, many models of PN exist and most have not been carefully evaluated. The goal of this study was to test the Ohio American Cancer Society model of PN as it relates to reducing time to diagnostic resolution among persons with abnormal breast, cervical, or colorectal cancer screening tests or symptoms.
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Myocardial T? mapping with respiratory navigator and automatic nonrigid motion correction.
Magn Reson Med
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Quantitative T? mapping was recently shown to be superior to T?-weighted imaging in detecting T? changes across myocardium. Pixel-wise T? mapping is sensitive to misregistration between the images used to generate the parameter map. In this study, utility of two motion-compensation strategies-(i) navigator gating with prospective slice correction and (ii) nonrigid registration-was investigated for myocardial T? mapping in short axis and horizontal long axis views. Navigator gating provides respiratory motion compensation, whereas registration corrects for residual cardiac and respiratory motion between images; thus, the two strategies provided complementary functions. When these were combined, respiratory-motion-induced T? variability, as measured by both standard deviation and interquartile range, was comparable to that in breath-hold T? maps. In normal subjects, this combined motion-compensation strategy increased the percentage of myocardium with T? measured to be within normal range from 60.1% to 92.2% in short axis and 62.3% to 92.7% in horizontal long axis. The new motion-compensated T? mapping technique, which combines navigator gating, prospective slice correction, and nonrigid registration to provide through-plane and in-plane motion correction, enables a method for fully automatic and robust free-breathing T? mapping.
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Standardizing the power of the Hosmer-Lemeshow goodness of fit test in large data sets.
Stat Med
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The Hosmer-Lemeshow test is a commonly used procedure for assessing goodness of fit in logistic regression. It has, for example, been widely used for evaluation of risk-scoring models. As with any statistical test, the power increases with sample size; this can be undesirable for goodness of fit tests because in very large data sets, small departures from the proposed model will be considered significant. By considering the dependence of power on the number of groups used in the Hosmer-Lemeshow test, we show how the power may be standardized across different sample sizes in a wide range of models. We provide and confirm mathematical derivations through simulation and analysis of data on 31,713 children from the Collaborative Perinatal Project. We make recommendations on how to choose the number of groups in the Hosmer-Lemeshow test based on sample size and provide example applications of the recommendations.
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Efficient Bayesian joint models for group randomized trials with multiple observation times and multiple outcomes.
Stat Med
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In this paper, we propose a Bayesian method for group randomized trials with multiple observation times and multiple outcomes of different types. We jointly model these outcomes using latent multivariate normal linear regression, which allows treatment effects to change with time and accounts for (i) intraclass correlation within groups; (ii) the correlation between different outcomes measured on the same subject; and (iii) the over-time correlation of each outcome. Moreover, we develop a set of innovative priors for the variance components, which yield direct inference on the correlations, avoid undesirable constraints, and allow utilization of information from previous studies. We illustrate through simulations that our model can improve estimation efficiency (lower posterior standard deviations) of intraclass correlations and treatment effects relative to single outcome models and models with diffuse priors on the variance components. We also demonstrate the methodology using body composition data collected in the Trial of Activity in Adolescent Girls.
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Randomized controlled trial of docosahexaenoic acid supplementation in midwestern U.S. human milk donors.
Breastfeed Med
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Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid important for neonatal neurodevelopment and immune homeostasis. Preterm infants fed donor milk from a Midwestern source receive only 20% of the intrauterine accretion of DHA. We tested the hypothesis that DHA supplementation of donor mothers would provide preterm infants with DHA intake equivalent to fetal accretion.
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Plasma lipid metabolites are associated with gestational age but not bronchopulmonary dysplasia.
Acta Paediatr.
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To test the hypothesis that plasma lipid metabolite levels in premature infants are associated with the development of bronchopulmonary dysplasia (BPD). The studies also tested a secondary hypothesis that plasma lipid metabolite levels were correlated with gestational age.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.