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Search Results: 1 - 10 of 159481 matches for " William F. Clark "
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Brief review: management of lupus nephritis–randomized controlled trials: an update  [PDF]
Shih-Han S. Huang, Ainslie Hildebrand, William F. Clark
Open Journal of Internal Medicine (OJIM) , 2011, DOI: 10.4236/ojim.2011.12006
Abstract: Lupus nephritis leads to significant morbidity and mortality in patients with systemic lupus erythematous. Immunosuppressive agents are recommended in management of Class III, IV and V lupus nephritis. The goals of therapy are to control the disease and to prevent relapse while minimizing side-effects of therapy. Most of the evidences in managements of Class III and IV lupus nephritis comes from randomized controlled trials using intravenous cyclophosphamides, oral mycophenolate mofetil and oral azathioprine. In Class V lupus nephritis, there are few studies available and they have assessed the use of intravenous cyclophsophamide, oral mycophenolates mofetil and oral cyclosporine. In this review article, we have summarized the major randomized controlled trials in managements of Class III, IV and V lupus nephritis and offer an interpretation of the evidence to date.
Differential response effects of data collection mode in a cancer screening study of unmarried women ages 40–75 years: A randomized trial
Melissa A Clark, Michelle L Rogers, Gene F Armstrong, William Rakowski, Frederick J Kviz
BMC Medical Research Methodology , 2008, DOI: 10.1186/1471-2288-8-10
Abstract: Three survey methods were evaluated for collecting data about mammography and Papanicolaou (hereafter, Pap) testing among heterosexual and sexual minority (e.g., lesbian and bisexual) women. Women ages 40–75 were recruited from June 2003 – June 2005 in Rhode Island. They were randomly assigned to receive: Self-Administered Mailed Questionnaire [SAMQ; N = 202], Computer-Assisted Telephone Interview [CATI; N = 200], or Computer-Assisted Self-Interview [CASI; N = 197]. Logistic regression models were computed to assess survey mode differences for 13 self-reported items related to cancer screenings, adjusting for age, education, income, race, marital status, partner gender, and recruitment source.Compared to women assigned to CATI, women assigned to SAMQ were less likely to report two or more years between most recent mammograms (CATI = 23.2% vs. SAMQ = 17.7%; AOR = 0.5, 95% CI = 0.3 – 0.8) and women assigned to CASI were slightly less likely to report being overdue for mammography (CATI = 16.5% vs. CASI = 11.8%; AOR = 0.5, 95% CI = 0.3 – 1.0) and Pap testing (CATI = 14.9% vs. CASI = 10.0%; AOR = 0.5, 95% CI = 0.2 – 1.0). There were no other consistent mode effects.Among participants in this sample, mode of data collection had little effect on the reporting of mammography and Pap testing behaviours. Other measures such as efficiency and cost-effectiveness of the mode should also be considered when determining the most appropriate form of data collection for use in monitoring indicators of cancer detection and control.Over 18 million women aged 40–75 in the United States are currently unmarried [1]. The designation of "unmarried" refers to women who are legally separated, divorced, widowed, or never legally married. Sexual minorities (e.g., lesbians and bisexuals) are an important segment of the unmarried female population. Sexual minority women may be living in committed relationships comparable to married heterosexual couples but are unable to legally marry in any stat
Do Planetary Encounters Reset Surfaces of Near Earth Asteroids?
David Nesvorny,William F. Bottke,David Vokrouhlicky,Clark R. Chapman,Scot Rafkin
Physics , 2010, DOI: 10.1016/j.icarus.2010.05.003
Abstract: Processes such as the solar wind sputtering and micrometeorite impacts can modify optical properties of surfaces of airless bodies. This explains why spectra of the main belt asteroids, exposed to these `space weathering' processes over eons, do not match the laboratory spectra of ordinary chondrite (OC) meteorites. In contrast, an important fraction of Near Earth Asteroids (NEAs), defined as Q-types in the asteroid taxonomy, display spectral attributes that are a good match to OCs. Here we study the possibility that the Q-type NEAs underwent recent encounters with the terrestrial planets and that the tidal gravity (or other effects) during these encounters exposed fresh OC material on the surface (thus giving it the Q-type spectral properties). We used numerical integrations to determine the statistics of encounters of NEAs to planets. The results were used to calculate the fraction and orbital distribution of Q-type asteroids expected in the model as a function of the space weathering timescale, t_sw (see main text for definition), and maximum distance, r*, at which planetary encounters can reset the surface. We found that t_sw ~ 1e6 yr (at 1 AU) and r* ~ 5 R_pl, where R_pl is the planetary radius, best fit the data. Values t_sw < 1e5 yr would require that r* > 20 R_pl, which is probably implausible because these very distant encounters should be irrelevant. Also, the fraction of Q-type NEAs would be probably much larger than the one observed if t_sw > 1e7 yr. We found that t_sw ~ q^2, where q is the perihelion distance, expected if the solar wind sputtering controls t_sw, provides a better match to the orbital distribution of Q-type NEAs than models with fixed t_sw. We also discuss how the Earth magnetosphere and radiation effects such as YORP can influence the spectral properties of NEAs.
Adherence with isoniazid for prevention of tuberculosis among HIV-infected adults in South Africa
Tom A Szakacs, Douglas Wilson, D William Cameron, Michael Clark, Paul Kocheleff, F James Muller, Anne E McCarthy
BMC Infectious Diseases , 2006, DOI: 10.1186/1471-2334-6-97
Abstract: Cross-sectional study of adherence using a questionnaire and urine test strips for detection of INH metabolites at two hospitals in Pietermaritzburg, South Africa. Participants were aged at least 18 years, HIV positive, and receiving INH for prevention of tuberculosis disease. Univariate and multivariate analyses are used to identify factors relevant to adherence.301 consecutive patients were recruited. 28% of participants had negative urine tests. 32 (37.2%, 95% CI25.4, 45.0) of the 86 patients who received INH from peripheral pharmacies said the pharmacy had run out of INH at some time, compared with central hospital pharmacies (p = 0.0001). In univariate analysis, a negative test was associated with self-reported missed INH doses (p = 0.043). Each 12-hour increment since last reported dose increased the likelihood of a negative test by 34% (p = 0.0007). Belief in INH safety was associated with a positive test (p = 0.021). In multivariate analysis, patients who believed INH is important for prevention of TB disease were more likely to be negative (p = 0.0086).Adequate drug availability at peripheral pharmacies remains an important intervention for TB prevention. Key questions may identify potentially non-adherent patients. In-house prepared urine tests strips are an effective and cheap method of objectively assessing INH adherence, and could be used an important tool in TB control programs.Tuberculosis (TB) remains a major global epidemic despite widespread awareness and effective prevention and therapy. Human immunodeficiency virus (HIV) infection has had a devastating effect on the TB epidemic. In South Africa an estimated two million people are co-infected, as are 60% of all patients with newly diagnosed TB [1].Accordingly, the World Health Organization and American Thoracic Society now recommend INH for treatment of latent TB infection (LTBI) in HIV-infected patients who are TST positive [2,3]. If skin testing is not feasible, INH is still recommended in regio
Feasibility of using polypropylene ground cover upon consideration of long-term responses of sweet cherry nutrition and profitability  [PDF]
Xinhua Yin, Clark F. Seavert
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.34072
Abstract: The impacts of synthetic polypropylene ground cover in the row area of sweet cherry (Prunus avium L.) trees (‘Regina’/’Gisela 6’) on soil nutrient availability, tree mineral nutrition and productivity, and economic returns were investigated on a Van Horn fine sandy loam soil at Hood River OR, from 2000 to 2007. Treatments included 2.44-m wide synthetic fabric ground cover made of black, woven poly-propylene over the row area of cherry trees (woven fabric), and no ground cover but with herbicide applications in the row area with the same width as the polypropylene ground cover (herbicide strip) – standard industry practice. This article reports the plant nutrition and soil fertility results of 2006 and 2007 and profitability and feasibility results of 2000 to 2007. Tree leaf nitrogen (N) concentrations were significantly higher with 9 to 14% increases using woven fabric compared with herbicide strip in 2006 and 2007. However, leaf sulfur (S) concentrations were significantly lowered with woven fabric in the two seasons. Woven fabric resulted in fruit with comparable quality and possible greater storability under enhanced fruit yields than herbicide strip in both years. Woven fabric was more profitable than herbicide strip based on an additional net present value of $2,606 ha-1 by the end of this study. Woven fabric had annual gross returns greater than annual costs in the fourth year after planting by $8,181 ha-1 relative to herbicide strip, and had cumulative net returns greater than total costs of all previous years in the sixth year after planting by $17,796 ha-1 over herbicide strip. However, to establish a sweet cherry orchard with woven fabric, the grower would spend an additional $4,332 ha-1 over herbicide strip. In conclusion, woven fabric is a profitable and sustainable in-row ground management alternative to herbicide strip for orchards from a long-term perspective.
Neuroprotective Efficacy of a New Brain-Penetrating C-Abl Inhibitor in a Murine Parkinson’s Disease Model
Syed Z. Imam, William Trickler, Shinya Kimura, Zbigniew K. Binienda, Merle G. Paule, William Slikker, Senlin Li, Robert A. Clark, Syed F. Ali
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065129
Abstract: Experimental evidence suggests that oxidative and nitrative mechanisms account for much of the dopaminergic neuronal injury in Parkinson’s disease (PD). The ubiquitously expressed non-receptor tyrosine kinase c-Abl is activated by oxidative stress and thus, may play a role in redox-mediated neurodegeneration. Recently, we reported that c-Abl is activated in PD and that a c-Abl inhibitor mitigated neuronal damage in a PD animal model, suggesting a novel neuroprotective therapeutic approach. In the studies presented here, we evaluated the efficacy of a potent and clinically relevant second-generation irreversible Abl kinase inhibitor, INNO-406, as a therapeutic agent for PD. Our studies reveal that INNO-406 is capable of preventing the progression of dopaminergic neuronal damage in a toxin-induced C57 mouse model of PD. Using bovine brain microvessel endothelium as an in vitro blood-brain barrier (BBB) model, we detected rapid and significant transfer of INNO-406. Additionally, pharmacokinetic analyses demonstrated significant nanomolar concentrations of INNO-406 in brain in the presence or absence of MPTP administration, however, INNO-406 did not alter the brain levels of MPP+ in MPTP-treated mice. Finally, we showed that 10 mg/kg of INNO-406 given to C57 mice for one week before MPTP treatment (4×20 mg/kg i.p., every 2 h) and then for one week after MPTP treatment decreased the loss of dopamine in the striatum by 45% and the loss of TH+ neurons in substantia nigra pars compacts by 40%. This treatment regimen also abrogated activation of c-Abl, tyrosine phosphorylation of the Abl substrate and E3-ubiquitin ligase parkin, and accumulation of the toxic parkin substrate AIMP2. We propose that compounds of the INNO-406 class of Abl inhibitors will be useful new neuroprotective drugs for the treatment of PD-like pathology in preclinical systems that should be easily translated to the clinic.
Measurement of Weight in Clinical Trials: Is One Day Enough?
Nisa M. Maruthur,William M. Vollmer,Jeanne M. Clark,Gerald J. Jerome,Lillian F. Lien,Catherine M. Loria,Lawrence J. Appel
Journal of Obesity , 2010, DOI: 10.1155/2010/413407
Abstract: Background. Weight is typically measured on a single day in research studies. This practice assumes negligible day-to-day weight variability, although little evidence exists to support this assumption. We compared the precision of measuring weight on one versus two days among control participants in the Weight Loss Maintenance trial. Methods. Trained staff measured weight on two separate days at baseline, 12 months, and 30 months (2004–2007). We calculated the standard deviation (SD) of mean weight change from baseline to the 12- and 30-month visits using (a) the first and (b) both daily weights from each visit and conducted a variance components analysis (2009). Results. Of the 316 participants with follow-up measurements, mean (SD) age was 55.8 (8.5) years, BMI was 30.8 (4.5) kg/m2, 64% were women, 36% were black, and 50% were obese. At 12 months, the SD of mean weight change was 5.1 versus 5.0 kg using one versus two days of weight measurements (=.76), while at 30 months the corresponding SDs were 6.3 and 6.3 kg (=.98). We observed similar findings within subgroups of BMI, sex, and race. Day-to-day variability within individuals accounted for <1% of variability in weight. Conclusions. Measurement of weight on two separate days has no advantage over measurement on a single day in studies with well-standardized weight measurement protocols.
Measurement of Weight in Clinical Trials: Is One Day Enough?
Nisa M. Maruthur,William M. Vollmer,Jeanne M. Clark,Gerald J. Jerome,Lillian F. Lien,Catherine M. Loria,Lawrence J. Appel
Journal of Obesity , 2010, DOI: 10.1155/2010/413407
Abstract: Background. Weight is typically measured on a single day in research studies. This practice assumes negligible day-to-day weight variability, although little evidence exists to support this assumption. We compared the precision of measuring weight on one versus two days among control participants in the Weight Loss Maintenance trial. Methods. Trained staff measured weight on two separate days at baseline, 12 months, and 30 months (2004–2007). We calculated the standard deviation (SD) of mean weight change from baseline to the 12- and 30-month visits using (a) the first and (b) both daily weights from each visit and conducted a variance components analysis (2009). Results. Of the 316 participants with follow-up measurements, mean (SD) age was 55.8 (8.5) years, BMI was 30.8 (4.5)?kg/ , 64% were women, 36% were black, and 50% were obese. At 12 months, the SD of mean weight change was 5.1?versus 5.0?kg using one versus two days of weight measurements , while at 30 months the corresponding SDs were 6.3 and 6.3?kg . We observed similar findings within subgroups of BMI, sex, and race. Day-to-day variability within individuals accounted for <1% of variability in weight. Conclusions. Measurement of weight on two separate days has no advantage over measurement on a single day in studies with well-standardized weight measurement protocols. 1. Introduction Short- and long-term variability in outcomes can affect power in research studies. Weight is usually measured on a single day per study visit (i.e., time point in study: baseline and followup) in clinical trials of weight loss or maintenance. However, day-to-day variability in weight within an individual may decrease precision, thus impacting necessary sample sizes. Because of this type of variability in blood pressure, sample size is optimized by using at least 3 sets of daily blood pressure measurements per study visit [1]. We aimed to evaluate the hypothesis that measurement of weight on one day is sufficiently precise compared to two days by (1) comparing the standard deviation of weight change based on one versus two days of measurements and (2) evaluating components of weight variability using data from the Weight Loss Maintenance (WLM) Trial [2]. 2. Methods 2.1. Study Design WLM was an NHLBI-supported, 4-site, and randomized controlled trial comparing 2 weight loss maintenance interventions to a self-directed control group in two phases: an initial 6-month weight-loss phase common to all participants (phase 1) and a randomized, 30-month weight-maintenance phase (phase 2). This study uses data from phase 2.
The benefits and risks of bacille Calmette-Guérin vaccination among infants at high risk for both tuberculosis and severe combined immunodeficiency: assessment by Markov model
Michael Clark, D William Cameron
BMC Pediatrics , 2006, DOI: 10.1186/1471-2431-6-5
Abstract: A Markov model was developed to simulate the natural histories of tuberculosis (TB) and SCID in children from birth to 14 years. The annual risk of tuberculous infection (ARI) and SCID incidence were varied in analyses. The model compared a scenario of no vaccination to intervention with BCG. Appropriate variability and uncertainty analyses were conducted. Outcomes included TB incidence and quality-adjusted life years (QALYs).In sensitivity analyses, QALYs were lower among vaccinated infants if the ARI was 0.1% and the rate of SCID was higher than 4.2 per 100,000. Assuming an ARI of 1%, this threshold increased to 41 per 100,000. In uncertainty analyses (Monte Carlo simulations) which assumed an ARI of 0.1%, QALYs were not significantly increased by BCG unless SCID incidence is 0. With this ARI, QALYs were significantly decreased among vaccinated children if SCID incidence exceeds 23 per 100,000. BCG is associated with a significant increase in QALYs if the ARI is 1%, and SCID incidence is below 5 per 100,000.The possibility that Canadian Aboriginal children are at increased risk for SCID has serious implications for continued BCG use in this population. In this context, enhanced TB Control – including early detection and treatment of infection – may be a safer, more effective alternative.Bacille Calmette-Guerin (BCG) is a live, attenuated vaccine derived from Mycobacterium bovis. The vaccine provides 65–95% protection against miliary and meningeal tuberculosis (TB) in children vaccinated as neonates [1]. Local and systemic adverse reactions to BCG have been summarized [2,3]. The most severe of these – and fortunately the rarest – is disseminated BCG infection. This complication usually occurs among children with underlying congenital or acquired immunodeficiency disorders [4,5].BCG use in Canada is confined to high-risk groups, and routine neonatal vaccination programs exist only in TB-endemic Aboriginal (First Nations and Inuit) communities. Since 1982, eight case
Do women delay family formation in expensive housing markets?
William A.V. Clark
Demographic Research , 2012,
Abstract: BACKGROUND Recent research by demographers and economists has examined the link between living costs and fertility outcomes. The literature has provided some evidence that high rents, or high housing costs, discourage fertility. OBJECTIVE I re-examine the hypothesis that delayed fertility (age at first birth) is related to the costs of housing measured either as rents or sales prices. METHODS I use data from the American Community Survey for 2006-2008 to construct mean age at first birth for women in a sample of 25 US metropolitan areas stratified by rents and sales prices. The sales prices for those metropolitan areas were from the National Association of Realtors. I use models of both aggregate relationships of mean age at first birth and metropolitan housing cost level measures and individual analyses of mean age and measures of ethnicity, education and labor force participation. RESULTS The effect of being in an expensive housing market is a delay of first births by three to four years, after controlling for education, ethnicity and labor market participation. However, the relatively modest fit of individual models suggest that while the housing market may play a role it is also clear that there is a complex structure to the decision- making around fertility, labor force participation and housing market entry. Overall completed fertility does not appear to be changed.
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