Helping You Find Full Text Journal Articles

Search Results:

Author: Bin Nan (98)


Jan
2018


View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Purpose To identify computed tomographic (CT) findings that are predictive of recurrence of colonic diverticulitis. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant, retrospective cohort study. Six abdominal fellowship-trained radiologists reviewed the CT studies of 440 consecutive subjects diagnosed with acute colonic diverticulitis between January 2004 and May 2008 to determine the involved segments, maximum wall thickness in the inflamed segment, severity of diverticulosis, presence of complications (abscess, fistula, stricture, or perforation), and severity of the inflammation.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2017

Approximately ¼ of patients with thoracic aortic aneurysms (TAAs) have concomitant abdominal aortic aneurysms (AAAs), thereby justifying the addition of an abdominal CT scan to a chest CT scan in patients with a newly diagnosed or suspected TAA. However, the prevalence of pelvic artery aneurysms (PAAs) in these patients is unknown. The purpose of this study was to determine the prevalence of PAAs in patients with TAAs and to assess what patient specific factors were associated with PAAs, thereby providing insight into the usefulness of pelvic imaging in TAA patients.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Cadmium has been linked to impaired cognitive function in adults and may cause behavioral, physiological and molecular abnormalities characteristic of Alzheimer's disease (AD) in animals. Evidence linking cadmium and AD in humans is limited, but supportive. In the most recent epidemiologic study, blood cadmium in U.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2017

Blood glucose is routinely measured prior toF-fluorodeoxyglucose (FDG) administration in positron emission tomography (PET) imaging to identify hyperglycemia that may affect image quality. In this study we explore the effects of blood glucose levels upon semi-quantitative standardized uptake value (SUV) measurements of target organs and tissues of interest and in particular address the relationship of blood glucose to FDG accumulation in the brain and liver.
436 FDG PET/CT consecutive studies performed for oncology staging in 229 patients (226 male) at the Ann Arbor Veterans Administration Healthcare System were reviewed.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2017

The menopausal transition (MT) is a critical period associated with physiologic changes that influence women's long-term health and longevity. Information is, however, limited regarding factors that influence age at the onset of the MT and its duration (ie, time from MT onset to the final menstrual period).
We analyzed data for 1,145 women from four sites of the Study of Women's Health Across the Nation who participated in the menstrual calendar substudy, had the start of the MT identified, and had no missing covariate information.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2016

We consider the problem of using permutation-based methods to test for treatment-covariate interactions from randomized clinical trial data. Testing for interactions is common in the field of personalized medicine, as subgroups with enhanced treatment effects arise when treatment-by-covariate interactions exist. Asymptotic tests can often be performed for simple models, but in many cases, more complex methods are used to identify subgroups, and non-standard test statistics proposed, and asymptotic results may be difficult to obtain.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2017

The purpose of this study was to determine the frequency in which the pelvis component of an abdominopelvic CT provides information that would influence clinical management in two separate groups of patients: those with previously resected pancreatic ductal adenocarcinoma (PDA) and those with locally advanced unresectable PDA.
This institutional review-board approved HIPAA compliant retrospective study with waived informed consent included 247 subjects with histologically proven PDA, including 153 subjects post-pancreaticoduodenectomy and 94 subjects with locally advanced unresectable disease. Imaging reports interpreted between January 2005 and December 2013 were obtained from our institution's Radiology Information System by searching a Cancer Registry database of PDA patients separately for the words "whipple" and "unresectable.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Estimation of change-point locations in the broken-stick model has significant applications in modeling important biological phenomena. In this article we present a computationally economical likelihood-based approach for estimating change-point(s) efficiently in both cross-sectional and longitudinal settings. Our method, based on local smoothing in a shrinking neighborhood of each change-point, is shown via simulations to be computationally more viable than existing methods that rely on search procedures, with dramatic gains in the multiple change-point case.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2016

Aortic aneurysms are a significant cause of mortality, and the presence of multiple aneurysms may affect treatment plans. The purpose of this study was to determine the frequency of abdominal aortic aneurysms (AAAs) in patients with thoracic aortic aneurysms (TAAs) and to establish whether patient specific factors, such as gender and comorbidities, influenced the frequency of AAAs, thereby indicating if and when abdominal aortic evaluation is justified. Electronic medical records were reviewed from 1000 patients with a computed tomography (CT) angiogram of the chest and abdomen and a clinical diagnosis of TAA from Cardiac Surgery clinic between 2008 and 2013.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2014

The primary motivation and application in this article come from brain imaging studies on cognitive impairment in elderly subjects with brain disorders. We propose a regularized Haar wavelet-based approach for the analysis of three-dimensional brain image data in the framework of functional data analysis, which automatically takes into account the spatial information among neighboring voxels. We conduct extensive simulation studies to evaluate the prediction performance of the proposed approach and its ability to identify related regions to the outcome of interest, with the underlying assumption that only few relatively small subregions are truly predictive of the outcome of interest.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2016

To investigate the inflammatory response in giant cell arteritis (GCA) by characterising the DNA methylation pattern within the temporal artery microenvironment.
Twelve patients with non-equivocal histological evidence for GCA and 12 age-matched, sex-matched and ethnicity-matched controls with normal biopsies were studied. DNA was extracted from the affected portions of temporal artery tissue in patients with GCA and from histologically confirmed normal arteries in controls.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2015

Caloric restriction mimetic drugs have geroprotective effects that delay or reduce risks for a variety of age-associated systemic diseases, suggesting that such drugs might also have the potential to reduce risks of blinding ophthalmologic conditions for which age is a major risk factor.
To determine whether the caloric restriction mimetic drug metformin hydrochloride is associated with reduced risk of open-angle glaucoma (OAG) in persons with diabetes mellitus.
Retrospective cohort study of patients aged 40 years or older with diabetes mellitus and no preexisting record of OAG in a large US managed care network from January 1, 2001, through December 31, 2010.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2015

ESTIMATING MEAN SURVIVAL TIME: WHEN IS IT POSSIBLE?

Scand Stat Theory Appl 2015 Jun;42(2):397-413
Ying Ding, Bin Nan
For right censored survival data, it is well known that the mean survival time can be consistently estimated when the support of the censoring time contains the support of the survival time. In practice, however, this condition can be easily violated because the follow-up of a study is usually within a finite window. In this article we show that the mean survival time is still estimable from a linear model when the support of some covariate(s) with nonzero coefficient(s) is unbounded regardless of the length of follow-up.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2015

Traditional voxel-level multiple testing procedures in neuroimaging, mostly p-value based, often ignore the spatial correlations among neighboring voxels and thus suffer from substantial loss of power. We extend the local-significance-index based procedure originally developed for the hidden Markov chain models, which aims to minimize the false nondiscovery rate subject to a constraint on the false discovery rate, to three-dimensional neuroimaging data using a hidden Markov random field model. A generalized expectation-maximization algorithm for maximizing the penalized likelihood is proposed for estimating the model parameters.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Persons with diabetes have accelerated muscle loss. The association of fasting and postchallenge glucose levels per se to grip strength, a clinical marker of poor physical function, and potential sex differences in this relationship has not been previously described.
Longitudinal cohort.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Chloride depletion alkalosis (CDA) is often seen as a consequence of diuresis in heart failure (HF) but its prognostic significance remains unknown. The purpose of this study was to evaluate the prognostic role of CDA in decompensated HF (DHF).
A retrospective cohort analysis was performed on 674 patients who were admitted with DHF.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2015

We propose a multivariate sparse group lasso variable selection and estimation method for data with high-dimensional predictors as well as high-dimensional response variables. The method is carried out through a penalized multivariate multiple linear regression model with an arbitrary group structure for the regression coefficient matrix. It suits many biology studies well in detecting associations between multiple traits and multiple predictors, with each trait and each predictor embedded in some biological functional groups such as genes, pathways or brain regions.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2015

Reproductive history, particularly maternal age at most recent birth, may reflect lower risk for chronic disease and mortality due to socioeconomic factors, lifestyle behaviors, or genetics. Reproductive history has not been examined with respect to hepatic steatosis, the most common liver disease in the United States. Our objective was to examine the association between reproductive history and hepatic steatosis.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2015

Thyroid-associated ophthalmopathy (TAO) is a common and debilitating manifestation of Graves disease (GD). Presently little is known about factors that may increase the risk of developing TAO among patients with GD.
To identify risk factors associated with the development of TAO among individuals with newly diagnosed GD.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2015

We consider the use of randomized clinical trial (RCT) data to identify simple treatment regimes based on some subset of the covariate space, A. The optimal subset, A, is selected by maximizing the expected outcome under a treat-if-in-A regime, and is restricted to be a simple, as it is desirable that treatment decisions be made with only a limited amount of patient information required. We consider a two-stage procedure.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2015

To examine the impact of a weight loss intervention upon follicle stimulating hormone (FSH) levels in postmenopause.
Participants were postmenopausal, overweight, glucose-intolerant women not using exogenous estrogen (n = 382) in the Diabetes Prevention Program. Women were randomized to intensive lifestyle change (ILS) with the goals of weight reduction of at least 7% of initial weight and 150 min per week of moderate-intensity exercise, metformin 850 mg twice a day, or placebo administered twice a day.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2014

We consider finite sample properties of the regularized high-dimensional Cox regression via lasso. Existing literature focuses on linear models or generalized linear models with Lipschitz loss functions, where the empirical risk functions are the summations of independent and identically distributed (iid) losses. The summands in the negative log partial likelihood function for censored survival data, however, are neither iid nor Lipschitz.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2013

Case-cohort design, an outcome-dependent sampling design for censored survival data, is increasingly used in biomedical research. The development of asymptotic theory for a case-cohort design in the current literature primarily relies on counting process stochastic integrals. Such an approach, however, is rather limited and lacks theoretical justification for outcome-dependent weighted methods due to non-predictability.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2014

Retinal ganglion cells are known to express estrogen receptors and prior studies have suggested an association between postmenopausal hormone (PMH) use and decreased intraocular pressure, suggesting that PMH use may decrease the risk for primary open-angle glaucoma (POAG).
To determine whether the use of 3 different classes of PMH affects the risk for POAG.
Retrospective longitudinal cohort analysis of claims data from women 50 years or older enrolled in a US managed-care plan for at least 4 years in which enrollees had at least 2 visits to an eye care provider during the period 2001 through 2009.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2014

We assessed recent trends in the use of diagnostic testing for neovascular age-related macular degeneration (NVAMD) and macular edema (ME).
Claims data from a managed-care network were analyzed on patients with NVAMD (n = 22,954) or ME (n = 31,810) to assess the use of fluorescein angiography (FA), fundus photography (FP), and optical coherence tomography (OCT) from 2001 to 2009. Repeated-measures logistic regression was performed to compare patients' odds of undergoing these procedures in 2001, 2005, and 2009.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2014

High ambient levels of ozone (O3) and fine particulate matter (PM2.5) are associated with cardiovascular morbidity and mortality, especially in people with preexisting cardiopulmonary diseases. Enhanced susceptibility to the toxicity of air pollutants may include individuals with metabolic syndrome (MetS).

View Full Text PDF Listings View primary source full text article PDFs.

May
2014

This study aims to examine whether blood pressure reductions differ by estrogen use among overweight glucose-intolerant women.
We conducted a secondary analysis of Diabetes Prevention Program postmenopausal participants who used oral estrogen with or without progestogen at baseline and 1-year follow-up (n = 324) versus those who did not use oral estrogen with or without progestogen at either time point (n = 382). Changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were examined by randomization arm (intensive lifestyle change [ILS], metformin 850 mg twice daily, or placebo).

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2014

To examine whether estrogen use potentiates weight loss interventions via sex steroid levels and whether endogenous sex steroid levels predict response to weight loss interventions among women not using estrogen.
The Diabetes Prevention Program randomized overweight or obese dysglycemic participants to lifestyle change with the goals of weight reduction of >7% of initial weight and 150 minutes per week of exercise, metformin, or placebo. In this secondary analysis, we examined sex steroid levels and reductions in weight and waist circumference (WC) among postmenopausal women using (n = 324) and not using (n = 382) oral estrogen.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2013

It is unknown whether intensive lifestyle modification (ILS) or metformin changes sex steroids among premenopausal women without a history of polycystic ovarian syndrome (PCOS).
We examined 1-year intervention impact on sex steroids (estradiol, testosterone, dehydroepiandrosterone, and androstenedione [A4]) and SHBG and differences by race/ethnicity.
A subgroup of Diabetes Prevention Program participants who were premenopausal, not using estrogen, without a history of PCOS or irregular menses, and who reported non-Hispanic white (NHW), Hispanic, or African-American race/ethnicity (n = 301).

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2014

Cross-ratio estimation for bivariate failure times with left truncation.

Lifetime Data Anal 2014 Jan 23;20(1):23-37. Epub 2013 May 23.
Tianle Hu, Xihong Lin, Bin Nan
The cross-ratio is an important local measure that characterizes the dependence between bivariate failure times. To estimate the cross-ratio in follow-up studies where delayed entry is present, estimation procedures need to account for left truncation. Ignoring left truncation yields biased estimates of the cross-ratio.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2013

It is unclear how lipids change in response to lifestyle modification or metformin among postmenopausal glucose intolerant women using and not using hormone therapy (HT). We examined the one-year changes in lipids among postmenopausal, prediabetic women in the Diabetes Prevention Program (DPP), and whether changes were mediated by sex hormones.
We performed a secondary analysis of a randomized controlled trial of 342 women who used HT at baseline and year 1 and 382 women who did not use HT at either time point.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2013

We consider the problem of variable selection for monotone single-index models. A single-index model assumes that the expectation of the outcome is an unknown function of a linear combination of covariates. Assuming monotonicity of the unknown function is often reasonable and allows for more straightforward inference.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2013

To assess interest among members of the general public in laser-assisted in situ keratomileusis (LASIK) surgery and how levels of interest in this procedure have changed over time in the United States and other countries.
Using the Google Trends Web site, we determined the weekly frequency of queries involving the term "LASIK" from January 1, 2007, through January 1, 2011, in the United States, United Kingdom, Canada, and India. We fit separate regression models for each of the countries to assess whether residents of these countries differed in their querying rates on specific dates and over time.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2013

Using nationally representative data from the United States, this paper analyzed the effect of a state’s medical malpractice environment on referral visits received by specialist physicians. The analytic sample included 12,839 ambulatory visits to specialist care doctors in office-based settings in the United States during 2003–2007. Whether the patient was referred for the visit was examined for its association with the state’s malpractice environment, assessed by the frequency and severity of paid medical malpractice claims, medical malpractice insurance premiums and an indicator for whether the state had a cap on non-economic damages.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2013

To determine if statins are associated with the development or progression of age-related macular degeneration (AMD).
A large, national insurance claims database was reviewed to identify individuals aged 60 years or older who were enrolled for ≥2 years and had ≥1 visits to an eye provider. Prescription claims for statins within a 24-month look-back period and outpatient lipid laboratory values were also reviewed.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2013

To relate serum leptin levels to prevalent and incident radiographic knee osteoarthritis (OA) and to determine if patterns of change in longitudinal serum leptin measures differ by knee OA status over a 10-year period.
Participants in the Michigan Study of Women's Health Across the Nation underwent bilateral knee radiographs at baseline and followup visits 2, 4, and 11 for ascertainment of knee OA status (Kellgren/Lawrence score ≥2). Serum leptin measures were available from baseline and followup visits 1 and 3-7.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2012

To determine whether racial disparities exist in the use of ancillary testing to evaluate individuals with open-angle glaucoma.
We identified all enrollees aged 40 years and older in a large US managed care network with retinal or optic nerve conditions that could warrant the use of ancillary testing. Among persons with open-angle glaucoma or glaucoma suspects, we performed repeated-measures multivariable logistic regression to determine the odds and probabilities each year of undergoing visual field testing, fundus photography, and other ocular imaging for black, white, Hispanic, and Asian American men and women and compared the groups.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2013

Among postmenopausal women who do not use estrogen therapy (ET), we have previously reported that intensive lifestyle modification (ILS) leads to increases in sex hormone-binding globulin (SHBG) and that such increases are associated with reductions in fasting plasma glucose (FPG) and 2-hour postchallenge glucose (2HG). Oral ET decreases FPG and increases 2HG while increasing both SHBG and estradiol (E2). It is unknown if ILS reduces glucose among ET users, if changes in SHBG and E2 might mediate any glucose decreases in ET users, and if these patterns differ from those in non-ET users.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2012

Sex hormones may differ by race/ethnicity in postmenopausal women. Whether racial/ethnic differences also exist among those who are overweight and glucose intolerant is not clear.
The objective of the study was to compare sex hormones by race/ethnicity [non-Hispanic white (NHW), Hispanic, African-American (AA)] in overweight, glucose-intolerant, postmenopausal women.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2011

In the analysis of bivariate correlated failure time data, it is important to measure the strength of association among the correlated failure times. One commonly used measure is the cross ratio. Motivated by Cox's partial likelihood idea, we propose a novel parametric cross ratio estimator that is a flexible continuous function of both components of the bivariate survival times.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2012

No longitudinal studies have examined how iron measures change over menopause. Our objectives were to examine iron measures in individual women at premenopause and at postmenopause and, secondarily, to determine if any changes contributed to insulin resistance.
In a subset of participants (n=70) in a longitudinal study of menopause, we measured ferritin, transferrin, and soluble transferrin receptor (sTfR) once in the premenopause and once in the postmenopause.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2012

To determine whether 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) affect the risk of developing open-angle glaucoma (OAG) in persons with hyperlipidemia.
Retrospective, longitudinal cohort analysis.
Individuals aged ≥60 years with hyperlipidemia enrolled in a national United States managed care network between 2001 and 2009.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2012

Whether endogenous sex hormones (ESH) [SHBG, estradiol, testosterone, and dehydroepiandrosterone (DHEA)] are altered by intensive lifestyle modification (ILS) or metformin and whether such changes affect glucose levels among dysglycemic postmenopausal women is unclear.
Our objective was to examine intervention impact on ESH and associations with fasting plasma glucose (FPG) and 2-h glucose changes among postmenopausal glucose-intolerant women.
We performed a secondary analysis of a randomized controlled trial.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2012

To determine the rates of keratoplasty for corneal endothelial disease (CED) from 2001 to 2009 in a large managed care network in the United States, factors that affect which patients undergo this procedure and surgical outcomes.
A retrospective review of data from a longitudinal cohort study.
Beneficiaries with CED aged ≥ 40 years who were receiving eye care during 2001 to 2009.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2012

To assess trends in the use of ancillary diagnostic tests in the evaluation of patients with open-angle glaucoma (OAG) and glaucoma suspects over the past decade.
Retrospective, longitudinal cohort analysis.
A total of 169 917 individuals with OAG and 395 721 individuals with suspected glaucoma aged ≥40 years enrolled in a national United States managed care network between 2001 and 2009.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2011

To determine whether an association exists between sleep apnea and open-angle glaucoma, normal-tension glaucoma, nonarteritic ischemic optic neuropathy (NAION), papilledema, or idiopathic intracranial hypertension (IIH) and whether treatment with continuous positive airway pressure affects the development of these conditions.
Retrospective, longitudinal cohort study.
Billing records for beneficiaries 40 years of age and older enrolled in a large United States managed care network from 2001 through 2007 were reviewed.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2011

To identify geographic and climatic risk factors associated with exfoliation syndrome (ES).
A retrospective study of 626 901 eye care recipients, dating from 2001 to 2007 from 47 US states in a managed care network. Incident ES cases-patients (N = 3367) were identified by using billing codes.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2011

To determine whether the risk for nonexudative and exudative age-related macular degeneration (AMD) varies for Americans of different Asian ethnicities.
Claims data from a large national United States managed care network were reviewed to identify Asian Americans age 40 and older who had ≥ 1 eye care visits from 2001 to 2007. International Classification of Disease (ICD-9CM) billing codes were used to identify enrollees with nonexudative and exudative AMD.

View Full Text PDF Listings View primary source full text article PDFs.

Back to top