Publications by authors named "LAWTON W"

Background: Although there is increased attention to designing and explaining clinical trials in ways that are clinically meaningful for patients, there is limited information on patient preferences, understanding, and perceptions of this content.

Methods: Maximum difference scaling (MaxDiff) methodology was used to develop a survey for assessing patients' understanding of 19 clinical terms and perceived importance of 9 endpoint surrogate phrases used in clinical trials and consent forms. The survey was administered electronically to individuals with metastatic breast cancer affiliated with the Metastatic Breast Cancer Alliance.

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Progress toward improvement in cancer therapy relies on clinical trials. Yet, only a minority of eligible patients with cancer enroll as a result of multiple barriers at the patient, investigator, center, and national level. However, the rise of the Internet and mobile technology has created a slew of tools with medical applications, from Web sites to apps to social media platforms, all of which may aide clinicians in our quest to improve the clinical research enterprise.

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Background: Acute kidney injury (AKI) is common in low- and middle-income countries, and is associated with a high mortality. The high mortality rate is in large part due to the inability to perform dialysis in resource-limited settings. Due to significant cost advantages, peritoneal dialysis (PD) has been used to treat AKI in these settings.

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Several models of Gastric Emptying (GE) have been employed in the past to represent the rate of delivery of stomach contents to the duodenum and jejunum. These models have all used a deterministic form (algebraic equations or ordinary differential equations), considering GE as a continuous, smooth process in time. However, GE is known to occur as a sequence of spurts, irregular both in size and in timing.

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Objective: The purpose of this study is to evaluate the efficacy of a behavioral self-regulation intervention vs. active control condition using a parallel-group randomized clinical trial with a sample of center hemodialysis patients with chronic kidney disease.

Method: Participants were recruited from 8 hemodialysis treatment centers in the Midwest.

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Recent studies have established that, in addition to the well-known kicked-Harper model (KHM), an on-resonance double-kicked rotor (ORDKR) model also has Hofstadter's butterfly Floquet spectrum, with strong resemblance to the standard Hofstadter spectrum that is a paradigm in studies of the integer quantum Hall effect. Earlier it was shown that the quasienergy spectra of these two dynamical models (i) can exactly overlap with each other if an effective Planck constant takes irrational multiples of 2π and (ii) will be different if the same parameter takes rational multiples of 2π. This work makes detailed comparisons between these two models, with an effective Planck constant given by 2πM/N, where M and N are coprime and odd integers.

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Objective: Previous examinations of depression as a predictor of mortality in end-stage renal disease have yielded inconsistent findings. We sought to clarify the possible link with mortality by assessing depression at an earlier stage of renal impairment before the uremic disease state and depressive symptoms become highly confounded, and then following patients during the period of disease progression.

Design: Prospective design using an assessment of depression before initiation of renal replacement therapy to predict mortality status an average of 81 months later in patients in the early stages of chronic kidney disease.

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Background: The treatment of ischaemic stroke with neuroprotective drugs has been unsuccessful, and whether these compounds can be used to reduce disability after recurrent stroke is unknown. The putative neuroprotective effects of antiplatelet compounds and the angiotensin II receptor antagonist telmisartan were investigated in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial.

Methods: Patients who had had an ischaemic stroke were randomly assigned in a two by two factorial design to receive either 25 mg aspirin (ASA) and 200 mg extended-release dipyridamole (ER-DP) twice a day or 75 mg clopidogrel once a day, and either 80 mg telmisartan or placebo once per day.

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Background: Prolonged lowering of blood pressure after a stroke reduces the risk of recurrent stroke. In addition, inhibition of the renin-angiotensin system in high-risk patients reduces the rate of subsequent cardiovascular events, including stroke. However, the effect of lowering of blood pressure with a renin-angiotensin system inhibitor soon after a stroke has not been clearly established.

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Background: Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel.

Methods: In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily.

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Research examining the role of social support in patient adjustment to chronic illness has been inconsistent suggesting that patient individual differences play a moderating role. This study examined the hypothesis that the relationship between social support and depressive symptoms would differ as a function of individual differences in trait Agreeableness. Fifty-nine patients with chronic kidney disease were assessed using the Social Provisions Scale, Beck Depression Inventory and NEO-Five-Factor Inventory and were followed-up a year and a half later.

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Among end-stage renal disease (ESRD) patients on hemodialysis, death from withdrawal from life-sustaining dialysis is increasingly common. The present study's objective was to examine depression as a potential risk factor for hemodialysis withdrawal. Two hundred forty ESRD hemodialysis (133 male and 107 female) patients were followed for an average of 4 years after depression symptom assessment.

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Participants in the present study were 207 patients with chronic kidney disease (CKD) who completed internal HLOC and depression measures at baseline and at an approximately 16-month follow-up period. Regression results indicated that after controlling for baseline level of depression, baseline internal HLOC was not a significant predictor of depression at follow-up. However, increases in internal HLOC over the 16-month follow-up were predictive of depression at follow-up.

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Background: Poor patient adherence is a widespread problem among patients undergoing hemodialysis for end-stage renal disease.

Purpose: The goal of this study was to examine the joint role of perceived restriction of control and individual differences in preference for control in predicting adherence to the hemodialysis regimen.

Methods: Participants were 49 patients recruited from five hemodialysis centers affiliated with the University of Iowa Hospitals and Clinics.

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Purpose: To determine the benefit of preprocedural three-dimensional gadolinium (Gd)-enhanced magnetic resonance (MR) angiography before percutaneous transluminal renal artery angioplasty and stent placement (PTRA/S) in terms of procedural success, iodinated contrast material load, and procedure duration.

Materials And Methods: Over an 18-month period, 39 patients underwent attempted percutaneous renal angioplasty with or without stent placement. A total of 48 renal arteries were treated (40 cases of atherosclerosis, one of stent restenosis, five of fibromuscular dysplasia, and two of transplant stenosis).

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The present study examined the efficacy of a behavioral intervention designed to increase adherence to fluid-intake restrictions among hemodialysis patients. Twenty intervention-group patients were compared with 20 matched control patients on an indicator of fluid-intake adherence at 3 time points. The Group x Time interaction was significant, indicating that patients in the 2 groups exhibited a differential pattern of change in fluid-intake adherence across the follow-up period.

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The present study examined the role of personality as a predictor of mortality among patients with chronic renal insufficiency. A prospective evaluation of the influence of personality on patient survival was conducted over an average 49-month period. Cox regression was used to evaluate the effects of 5 dimensions of personality in a sample of 174 patients (100 male and 74 female).

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Purpose: To evaluate the hemodynamic outcome of technically successful percutaneous transluminal renal artery angioplasty and stent placement (PTRAS) with duplex ultrasonography (US).

Materials And Methods: Eighteen patients who underwent PTRAS in 22 renal arteries were prospectively examined. All had abnormal preprocedural duplex US findings.

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Improvement in patient quality of life is a central goal of renal transplantation. This study examined the hypothesis that change in depression following transplantation would vary as a function of patient coping preferences. Sixty patients were assessed with the Krantz Health Opinion Survey and the Beck Depression Inventory while on the waiting list for a cadaveric renal transplant.

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Proteinmorphosis is a physically-based interactive modeling system for simulating large or small conformational changes of proteins and protein complexes. It takes advantage of the cross-linked one-dimensional nature of protein chains. The user can, based on her chemical knowledge, pull pairs of points (lying either on a single protein or on different molecules) together by specifying geometric distance constraints.

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Previous conclusions regarding the role of social support in hemodialysis adherence are inconsistent, suggesting that other factors may moderate this relationship. Using the Five-Factor Model of Personality, we examined the hypothesis that conscientiousness would interact with social support in predicting fluid-intake and medication adherence in a sample of 56 chronic hemodialysis patients. Hierarchical regression analyses (controlling for demographic, clinical, and other personality variables) revealed a significant interaction between social support and conscientiousness.

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Objective: The present study examined the joint role of cynical hostility and powerful others health locus of control expectancies in predicting regimen adherence in a sample of center hemodialysis patients.

Method: Forty-eight hemodialysis patients completed the Cook-Medley Hostility (Ho) Scale and the Powerful Others Health Locus of Control (PHLC) scale. Adherence to the fluid-restriction and phosphorus reduction components of the treatment regimen was assessed by examining patients' interdialysis session weight gains and serum phosphorus (P) levels.

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Previous research involving individuals facing chronic health problems suggests that an attentional style characterized by pronounced monitoring of threat-relevant information is associated with poorer behavioral and emotional adjustment. This study examined the hypothesis that a pronounced monitoring style would be associated with poorer medical regimen adherence in a sample of 51 chronic hemodialysis patients. Hierarchical regression analyses (controlling for demographic factors and trait anxiety) revealed that "high monitors" exhibited higher interdialysis weight gains and higher serum K values reflecting poorer adherence to fluid-intake and dietary restrictions.

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