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Significant Heterogeneity (significant + heterogeneity)
Selected AbstractsEfficacy of maintenance treatment with naltrexone for opioid dependence: a meta-analytical reviewADDICTION, Issue 4 2006Björn Axel Johansson ABSTRACT Aims To determine the efficacy of naltrexone in reducing illicit opioid use and the potential moderating role of treatment retention. ,Design First, randomized controlled trials (RCTs) comparing the regimens of treatment using the opioid antagonist, naltrexone, with controls were analysed by meta-analysis for treatment effect with regard to a range of outcome criteria. The degree of heterogeneity was also determined. The moderating effect of other interventions during naltrexone maintenance was then estimated, particularly with regard to their effect on treatment retention. Participants Fifteen studies involving 1071 patients were found. Measurements All available outcomes were analysed in 10 studies of naltrexone versus control (seven placebo) and six studies of randomized psychosocial/psychopharmacological interventions. Findings Significant heterogeneity was found in the efficacy of naltrexone. Level of retention in treatment was found to be a moderator, explaining most of the heterogeneity found. Overall, naltrexone was significantly better than control conditions in reducing the number of opioid-positive urines. This effect was only present in the high retention subgroup for differences in retention. Contingency management (CM) increased retention and naltrexone use, resulting in a reduced number of opioid-positive urines. Conclusion Retention is important to the effect of naltrexone in treating opioid dependence. Contingency management is a promising method of increasing retention. [source] The burden of influenza in East and South-East Asia: a review of the English language literatureINFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 3 2008James M. Simmerman Abstract, While human infections with avian influenza A (H5NI) viruses in Asia have prompted concerns about an influenza pandemic, the burden of human influenza in East and Southeast Asia has received far less attention. We conducted a review of English language articles on influenza in 18 countries in East and Southeast Asia published from 1980 to 2006 that were indexed on PubMed. Articles that described human influenza-associated illnesses among outpatients or hospitalized patients, influenza-associated deaths, or influenza-associated socioeconomic costs were reviewed. We found 35 articles from 9 countries that met criteria for inclusion in the review. The quality of articles varied substantially. Significant heterogeneity was noted in case definitions, sampling schemes and laboratory methods. Early studies relied on cell culture, had difficulties with specimen collection and handling, and reported a low burden of disease. The recent addition of PCR testing has greatly improved the proportion of respiratory illnesses diagnosed with influenza. These more recent studies reported that 11,26% of outpatient febrile illness and 6-14% of hospitalized pneumonia cases had laboratory-confirmed influenza infection. The influenza disease burden literature from East and Southeast Asia is limited but expanding. Recent studies using improved laboratory testing methods and indirect statistical approaches report a substantial burden of disease, similar to that of Europe and North America. Current increased international focus on influenza, coupled with unprecedented funding for surveillance and research, provide a unique opportunity to more comprehensively describe the burden of human influenza in the region. [source] Identification of microsatellite DNA markers for population structure analysis in Indian major carp, Cirrhinus mrigala (Hamilton-Buchanan, 1882)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2004K. K. Lal Summary Forty-four primer sequences available for four cyprinid fishes were tested to amplify microsatellite loci in Indian major carp, Cirrhinus mrigala. A total of 12 loci were successfully amplified with clear scorable patterns and five thereof were polymorphic. Suitability of the identified polymorphic loci in population structure analysis of C. mrigala was assessed. Genetic variation was examined in 76 specimens collected from five different rivers. The mean observed heterozygosity ranged from 0.247 to 0.333. Significant heterogeneity in allele frequencies was detected, indicating that the samples analysed did not belong to homogenous populations. The identified microsatellite markers are promising for the analysis of intraspecific divergence in C. mrigala across its distribution range. [source] Human brain aminopeptidase A: biochemical properties and distribution in brain nucleiJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Nadia De Mota Abstract Aminopeptidase A (APA) generated brain angiotensin III, one of the main effector peptides of the brain renin angiotensin system, exerting a tonic stimulatory effect on the control of blood pressure in hypertensive rats. The distribution of APA in human brain has not been yet studied. We first biochemically characterized human brain APA (apparent molecular mass of 165 and 130 kDa) and we showed that the human enzyme exhibited similar enzymatic characteristics to recombinant mouse APA. Both enzymes had similar sensitivity to Ca2+. Kinetic studies showed that the Km (190 ,mol/L) of the human enzyme for the synthetic substrate- l -glutamyl-,-naphthylamide was close from that of the mouse enzyme (256 ,mol/L). Moreover, various classes of inhibitors including the specific and selective APA inhibitor, (S)-3-amino-4-mercapto-butyl sulfonic acid, had similar inhibitory potencies toward both enzymes. Using (S)-3-amino-4-mercapto-butyl sulfonic acid, we then specifically measured the activity of APA in 40 microdissected areas of the adult human brain. Significant heterogeneity was found in the activity of APA in the various analyzed regions. The highest activity was measured in the choroids plexus and the pineal gland. High activity was also detected in the dorsomedial medulla oblongata, in the septum, the prefrontal cortex, the olfactory bulb, the nucleus accumbens, and the hypothalamus, especially in the paraventricular and supraoptic nuclei. Immunostaining of human brain sections at the level of the medulla oblongata strengthened these data, showing for the first time a high density of immunoreactive neuronal cell bodies and fibers in the motor hypoglossal nucleus, the dorsal motor nucleus of the vagus, the nucleus of the solitary tract, the Roller nucleus, the ambiguus nucleus, the inferior olivary complex, and in the external cuneate nucleus. APA immunoreactivity was also visualized in vessels and capillaries in the dorsal motor nucleus of the vagus and the inferior olivary complex. The presence of APA in several human brain nuclei sensitive to angiotensins and involved in blood pressure regulation suggests that APA in humans is an integral component of the brain renin angiotensin system and strengthens the idea that APA inhibitors could be clinically tested as an additional therapy for the treatment of certain forms of hypertension. [source] A role for ecology in male mate discrimination of immigrant females in Calopteryx damselflies?BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010MAREN WELLENREUTHER Sexual selection against immigrants is a mechanism that can regulate premating isolation between populations but, so far, few field studies have examined whether males can discriminate between immigrant and resident females. Males of the damselfly Calopteryx splendens show mate preferences and are able to force pre-copulatory tandems. We related male mate responses to the ecological characteristics of female origin, geographic distances between populations, and morphological traits of females to identify factors influencing male mate discrimination. Significant heterogeneity between populations in male mate responses towards females was found. In some populations, males discriminated strongly against immigrant females, whereas the pattern was reversed or nonsignificant in other populations. Immigrant females were particularly attractive to males when they came from populations with similar predation pressures and densities of conspecifics. By contrast, immigrant females from populations with strongly dissimilar predation pressures and conspecific densities were not attractive to males. Differences in the abiotic environment appeared to affect mating success to a lesser degree. This suggests that male mate discrimination is context-dependent and influenced by ecological differences between populations, a key prediction of ecological speciation theory. The results obtained in the present study suggest that gene-flow is facilitated between ecologically similar populations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 506,518. [source] Regional variations in action potential alternans in isolated murine Scn5a+/, hearts during dynamic pacingACTA PHYSIOLOGICA, Issue 2 2010G. D. K. Matthews Abstract Aim:, Clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a+/, hearts modelling Brugada syndrome (BrS) for the first time. Methods:, A dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 ,m) and quinidine (5 ,m) known to exert pro- and anti-arrhythmic effects in BrS. Results:, Sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI,) were determined. Kruskal,Wallis tests followed by Bonferroni-corrected Mann,Whitney U -tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a+/, hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a+/, hearts. Conclusion:, These findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS. [source] No evidence for switching the antidepressant: systematic review and meta-analysis of RCTs of a common therapeutic strategyACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2010T. Bschor Bschor T, Baethge C. No evidence for switching the antidepressant: systematic review and meta-analysis of RCTs of a common therapeutic strategy. Objective:, Switching antidepressants is a common strategy for managing treatment-resistant depressed patients. However, no systematic reviews have been conducted to date. Method:, We systematically searched MEDLINE/EMBASE/Cochrane Central Register of Controlled Trials and additional sources. We included double-blind studies of patients with depressive symptomatology who were not responding to initial antidepressant monotherapy and were subsequently randomized to another antidepressant or to continue the same antidepressant. Results were pooled for meta-analysis of response + remission rates using a fixed-effects model. Results:, A total of three studies were included. Switching to another antidepressant was not superior to continuing the initial antidepressant in any of these studies. Our meta-analysis showed no significant advantages to either strategy and no significant heterogeneity of results [OR for response rates: 0.85 (95% CI: 0.55,1.30) favoring continuing]. Conclusion:, There is a discrepancy between the published evidence and the frequent decision to switch antidepressants, indicating an urgent need for more controlled studies. Pending such studies we recommend that physicians rely on more thoroughly evaluated strategies. [source] Effectiveness of Corticosteroid Treatment in Acute Pharyngitis: A Systematic Review of the LiteratureACADEMIC EMERGENCY MEDICINE, Issue 5 2010Andrew Wing Abstract Objectives:, The objective was to examine the effectiveness of corticosteroid treatment for the relief of pain associated with acute pharyngitis potentially caused by group A beta-hemolytic Streptococcus (GABHS). Methods:, This was a systematic review of the literature. Data sources used were electronic databases (Cochrane Library, MEDLINE, EMBASE, Biosis Previews, Scopus, and Web of Science), controlled trial registration websites, conference proceedings, study references, experts in the field, and correspondence with authors. Selection criteria consisted of randomized controlled trials (RCTs) in which corticosteroids, alone or in combination with antibiotics, were compared to placebo or any other standard therapy for treatment of acute pharyngitis in adult patients, pediatric patients, or both. Two reviewers independently assessed for relevance, inclusion, and study quality. Weighted mean differences (WMDs) were calculated and are reported with corresponding 95% confidence intervals (CIs). Results:, From 272 potentially relevant citations, 10 studies met the inclusion criteria. When compared to placebo, corticosteroids reduced the time to clinically meaningful pain relief (WMD = ,4.54 hours; 95% CI = ,7.19 to ,1.89); however, they provided only a small reduction in pain scores at 24 hours (WMD = ,0.90 on a 0,10 visual analog scale; 95% CI = ,1.5 to ,0.3). Heterogeneity among pooled studies was identified for both outcomes (I2 = 81 and 74%, respectively); however, the GABHS-positive subgroup receiving corticosteroid treatment did have a significant mean reduction in time to clinically meaningful pain relief of 5.22 hours (95% CI = ,7.02 to ,3.42; I2 = 0%). Short-term side effect profiles between corticosteroids and placebo groups were similar. Conclusions:, Corticosteroid administration for acute pharyngitis was associated with a relatively small effect in time to clinically meaningful pain relief (4.5-hour reduction) and in pain relief at 24 hours (0.9-point reduction), with significant heterogeneity in the pooled results. Decision-making should be individualized to determine the risks and benefits; however, corticosteroids should not be used as routine treatment for acute pharyngitis. ACADEMIC EMERGENCY MEDICINE 2010; 17:476,483 © 2010 by the Society for Academic Emergency Medicine [source] Sexual orientation and substance use trajectories in emerging adulthoodADDICTION, Issue 7 2010Amelia E. Talley ABSTRACT Aims The current study examined developmental changes in substance use behaviors (SUBS) based upon sexual orientation. The analyses also attempted to address a number of methodological limitations in the extant longitudinal literature (i.e. distinct operationalizations of sexual orientation, timing of sexual orientation assessment with respect to reports of SUBs, non-linear growth). Participants Data were drawn from a longitudinal study of incoming first-time college students at a large public university (n = 3720). Design After a paper-and-pencil assessment just prior to matriculation, participants completed a web-based survey every fall and spring for 4 years (sub-sample n = 2854). Findings Latent growth models revealed that sexual minorities demonstrated significant heterogeneity with regard to substance use trajectories. Initial levels and trajectories of the frequency of substance use for sexual minority individuals were distinct, generally, from their exclusively heterosexual peers. Methodologically, the timing of the assessment of sexual orientation influenced the results, and modeling non-linear components indicated that sexual minorities are at risk for exponential increases in their frequency of certain SUBs over time (i.e. drunkenness; cannabis use). Conclusions Sexual minority and majority individuals exhibited differences in SUBs during emerging adulthood, especially when using self-identification to define sexual orientation. Individuals who endorsed a sexual minority self-identification at the onset of emerging adulthood, as opposed to 4 years later, evidenced exponential increases in rates of drunkenness and cannabis use. These results support that the timing of assessment is important and that some trajectories of sexual minority SUBs are non-linear during this developmental period. [source] Fitness and body size in mature odonatesECOLOGICAL ENTOMOLOGY, Issue 2 2000Natalia Sokolovska Summary The relationship between body size and fitness components in odonates was examined using a meta-analysis of 33 published studies. There was a positive and significant overall effect of body size on mating rate and lifetime mating success among males. There was also a weaker but still significant positive effect of body size on survivorship of males. The relationship between body size, mating rate, longevity, and lifetime mating success differed significantly between males of territorial and nonterritorial species. The effect of body size was significant for all fitness components in territorial species but significant only for longevity and lifetime mating success in nonterritorial species. Effect sizes appeared to be strongest on longevity in both sexes, and on male mating rate in territorial species. Other effect sizes, even when significant, were small. Despite a much smaller data set, female fitness also increased significantly with body size. Both clutch size and longevity showed a significant positive relationship with body size. These results suggest that there is a general fitness benefit to large size in odonates. Nevertheless, significant heterogeneity is apparent in this effect, which can be attributed to sex, mating system, and fitness component. Finally, these analyses point to inadequacies in the current data that need further study before the potentially rich patterns in size effects on fitness can be explored more thoroughly. [source] Mortgage Terminations, Heterogeneity and the Exercise of Mortgage OptionsECONOMETRICA, Issue 2 2000Yongheng Deng As applied to the behavior of homeowners with mortgages, option theory predicts that mortgage prepayment or default will be exercised if the call or put option is ,in the money' by some specific amount. Our analysis: tests the extent to which the option approach can explain default and prepayment behavior; evaluates the practical importance of modeling both options simultaneously; and models the unobserved heterogeneity of borrowers in the home mortgage market. The paper presents a unified model of the competing risks of mortgage termination by prepayment and default, considering the two hazards as dependent competing risks that are estimated jointly. It also accounts for the unobserved heterogeneity among borrowers, and estimates the unobserved heterogeneity simultaneously with the parameters and baseline hazards associated with prepayment and default functions. Our results show that the option model, in its most straightforward version, does a good job of explaining default and prepayment, but it is not enough by itself. The simultaneity of the options is very important empirically in explaining behavior. The results also show that there exists significant heterogeneity among mortgage borrowers. Ignoring this heterogeneity results in serious errors in estimating the prepayment behavior of homeowners. [source] Online support for smoking cessation: a systematic review of the literatureADDICTION, Issue 11 2009Lion Shahab ABSTRACT Aim To examine the efficacy and acceptability of online, interactive interventions for smoking cessation and to identify treatment effect moderators and mediators. Methods A systematic review and meta-analysis of the literature (1990,2008) was conducted, finding 11 relevant randomized controlled trials. Data were extracted and risk ratios and risk differences estimated with a random effects model. Results There was no evidence of publication bias. Included trials were of variable methodological quality. Web-based, tailored, interactive smoking cessation interventions were effective compared with untailored booklet or e-mail interventions [rate ratio (RR) 1.8; 95% confidence interval (CI) 1.4,2.3] increasing 6-month abstinence by 17% (95% CI 12,21%). No overall effect of interactive compared with static web-based interventions was detected but there was significant heterogeneity, with one study obtaining a clear effect and another failing to find one. Few moderating or mediating factors were evaluated in studies and those that were had little effect. Pooled results suggest that only interventions aimed at smokers motivated to quit were effective (RR 1.3, 95% CI 1.0,1.7). Fully automated interventions increased smoking cessation rates (RR 1.4, 95% CI 1.0,2.0), but evidence was less clear-cut for non-automated interventions. Overall, the web-based interventions evaluated were considered to be acceptable and user satisfaction was generally high. Conclusion Interactive, web-based interventions for smoking cessation can be effective in aiding cessation. More research is needed to evaluate the relative efficacy of interactive web-based interventions compared with static websites. [source] CYP2C9 and CYP2C19 genetic polymorphisms: frequencies in the south Indian populationFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 1 2005Rosemary Jose Abstract The aim of the study was to establish the frequencies of CYP2C9*1, *2, *3 and CYP2C19*1, *2 and *3 in the south Indian population and to compare them with the inter-racial distribution of the CYP2C9 and CYP2C19 genetic polymorphisms. Genotyping analyses of CYP2C9 and CYP2C19 were conducted in unrelated, healthy volunteers from the three south Indian states of Andhra Pradesh, Karnataka and Kerala, by the polymerase chain reaction,restriction fragment-length polymorphism (PCR,RFLP). The allele frequencies of the populations of these three states were then pooled with our previous genotyping data of Tamilians (also in south India), to arrive at the distribution of CYP2C9 and CYP2C19 alleles in the south Indian population. Frequencies of CYP2C9 and CYP2C19 alleles and genotypes among various populations were compared using the two-tailed Fisher's exact test. The frequencies of CYP2C9*1, *2 and *3 in the south Indian population were 0.88 (95% CI 0.85,0.91), 0.04 (95% CI 0.02,0.06) and 0.08 (95% CI 0.06,0.11), respectively. The frequencies of CYP2C9 genotypes *1/*1, *1/*2, *1/*3, *2/*2, *2/*3 and *3/*3 were 0.78 (95% CI 0.74,0.82), 0.05 (95% CI 0.03,0.07), 0.15 (95% CI 0.12,0.18), 0.01 (95% CI 0.0,0.02), 0.01 (95% CI 0.0,0.02) and 0.0, respectively. CYP2C19*1, *2 and *3 frequencies were 0.64 (95% CI 0.60,0.68), 0.35 (95% CI 0.31,0.39) and 0.01 (95% CI 0.0,0.03), respectively. As a result of a significant heterogeneity, the data on CYP2C19 genotype frequencies were not pooled. The frequency of CYP2C9*2 mutant alleles in south Indians was higher than in Chinese and Caucasians, while CYP2C9*3 was similar to Caucasians. CYP2C19*2 was higher than in other major populations reported so far. The relatively high CYP2C19 poor-metabolizer genotype frequency of 12.6% indicates that over 28 million south Indians are poor metabolizers of CYP2C19 substrates. [source] What determines conformity to Bergmann's rule?GLOBAL ECOLOGY, Issue 6 2007Shai Meiri ABSTRACT Aim, Bergmann's rule, the tendency of body size within species in bird and mammal populations to be positively correlated with latitude, is among the best known biogeographical generalizations. The factors behind such clines, however, are not well understood. Here we use a large data base of 79 mammalian carnivore species to examine the factors affecting latitudinal size clines. Location, Worldwide. Methods, We measured the skulls and teeth of carnivores in natural history museums, and calculated the amount of variation in size explained by latitude, supplementing our measurements with published data. We examined the effects of a number of variables on the tendency to show latitudinal clines. Results, We found that geographical range and latitudinal extent are strongly related to size clines. Minimum temperatures across the range, net primary productivity and habitat diversity also have some, albeit much less, influence. Main conclusions, We suggest that species with large geographical ranges are likely to encounter significant heterogeneity in those factors that influence body size, and are thus likely to exhibit size clines. However, the key factors that determine body size may not always operate along a latitudinal (or other geographical) cline, but be spatially linked to patches in the species range. One such important factor is likely to be food availability, which we show is a strong predictor of size in the brown bear (Ursus arctos) but is not associated with a latitudinal cline. We argue that the spatial distribution of key resources within the species range constitutes a significant predictor of carnivore body size. [source] Coffee drinking and hepatocellular carcinoma risk: A meta-analysis,HEPATOLOGY, Issue 2 2007Francesca Bravi Several studies suggest an inverse relation between coffee drinking and risk of hepatocellular carcinoma (HCC). We conducted a meta-analysis of published studies on HCC that included quantitative information on coffee consumption. Ten studies were retrieved (2,260 HCC cases), including 6 case,control studies from southern Europe and Japan (1551 cases) and 4 cohort studies from Japan (709 cases). The summary relative risk (RR) for coffee drinkers versus non-drinkers was 0.54 (95% confidence interval [CI] 0.38-0.76) for case,control studies and 0.64 (95% CI 0.56-0.74) for cohort studies. The overall RR was 0.59 (95% CI 0.49-0.72), with significant heterogeneity between studies. The overall summary RR for low or moderate coffee drinkers was 0.70 (95% CI 0.57-0.85), and that for high drinkers was 0.45 (95% CI 0.38-0.53). The summary RR for an increase of 1 cup of coffee per day was 0.77 (95% CI 0.72-0.83) from case,control studies, 0.75 (95% CI 0.65-0.85) from cohort studies, and 0.77 (95% CI 0.72-0.82) overall. The consistency of an inverse relation between coffee drinking and HCC across study design and geographic areas weighs against a major role of bias or confounding. Coffee drinking has also been related to reduced risk of other liver diseases, thus suggesting a continuum of the favorable effect of coffee on liver function. However, subjects with liver conditions may selectively reduce their coffee consumption. Conclusion: The present analysis provides evidence that the inverse relation between coffee and HCC is real, though inference on causality remains open to discussion. (HEPATOLOGY 2007.) [source] A welfare analysis of social security in a dynastic framework*INTERNATIONAL ECONOMIC REVIEW, Issue 4 2003Luisa Fuster In this article, we study the welfare effects of unfunded social security in a general equilibrium model populated with overlapping generations of altruistic individuals that differ in lifetime expectancy and earnings ability. Contrary to previous research, our results indicate that steady-state welfare increases with social security for most households, although by very different amounts. This result is mainly due to two factors. First, the presence of two-sided altruism significantly mitigates the crowding out effect of unfunded social security. Second, ability shocks and uncertain lifetimes generate significant heterogeneity among households to yield different induced preferences for social security. [source] Temporal and Spatial Distributions of Rotifers in Xiangxi Bay of the Three Gorges Reservoir, ChinaINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5 2009Shuchan Zhou Abstract From July 2003 to June 2005, investigations of rotifer temporal and spatial distributions were car-ried out in a bay of the Three Gorges Reservoir, Xiangxi Bay, which is the downstream segment of the Xiangxi River and the nearest bay to the Three Gorges Reservoir dam in Hubei Province, China. Thirteen sampling sites were selected. The results revealed a high species diversity, with 76 species, and 14 dominant species; i.e., Polyarthra vulgaris, Keratella cochlearis, Keratella valga, Synchaeta tremula, Synchaeta stylata, Trichocerca lophoessa, Trichocerca pusilla, Brachionus angularis, Brachionus calyciflorus, Brachionus forficula forficula, Ascomorpha ovalis, Conochilus unicornis, Ploesoma truncatum and Anuraeopsis fissa. After the first year of the reservoir impoundment, the rotifer community was dominated by ten species; one year later it was dominated by eight species. The community in 2003/2004 was dissimilar to that in 2004/2005, which resulted from the succes-sion of the dominant species. The rotifer community exhibited a patchy distribution, with significant heterogeneity observed along the longitudinal axis. All rotifer communities could be divided into three groups, corresponding to the riverine, the transition and the lacustrine zone, respectively. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quality and Outcomes of Heart Failure Care in Older Adults: Role of Multidisciplinary Disease-Management ProgramsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2002Ali Ahmed MD, FACP PURPOSE: To determine whether the management of heart failure by specialized multidisciplinary heart failure disease-management programs was associated with improved outcomes. BACKGROUND: The advent of angiotensin-converting enzyme inhibitors, beta-blockers, and spironolactone has revolutionized the management of heart failure. Randomized double-blind studies have demonstrated survival benefits of these drugs in heart failure patients. Nevertheless, in spite of these advances, heart failure continues to be a syndrome of poor outcomes.1,4 There is also evidence that a significant portion of heart failure patients does not receive this evidence-based therapy that reduces morbidity and mortality.5,7 Various disease-management programs have been proposed and tested to improve the quality of heart failure care. Most of these programs are specialized multidisciplinary heart failure clinics lead by cardiologists or heart failure specialists and conducted by nurses or nurse practitioners. Similar to the Department of Veterans Affairs (VA) multidisciplinary geriatric assessment clinics, these clinics also use many other services, including pharmacists, dietitians, physical therapists, and social workers. Some of these programs also have an affiliated home health service. Several observation studies, using mostly pre- and postcomparison designs, have demonstrated the effectiveness of these programs in the process of care, resource use, healthcare costs, and clinical outcomes in patients with heart failure.8 Risk of hospitalization was reduced by 50% to 85% in six of the studies.8 Subsequently, several randomized trials were conducted to determine the effectiveness of these programs. The purpose of this systematic review was to determine the effectiveness of these programs on mortality and hospitalization rates of heart failure patients. METHODS: Published articles on human randomized trials involving specialized heart failure disease-management programs in all languages were searched using Medline from 1966 to 1999 and other online databases using the following terms and Medical Subject Headings: case management (exp); comprehensive health care (exp); disease management (exp); health services research (exp); home care services (exp); clinical protocols (exp); patient care planning (exp); quality of health care (exp); nurse led clinics; special clinics; and heart failure, congestive (exp). In addition, a manual search of the bibliographies of searched articles was performed to identify articles otherwise missed in the above search. Personal communications were made with three authors to obtain further data on their studies. Using a data abstraction tool, two of the investigators separately abstracted data from the selected articles. Data from the selected studies were combined using the DerSimonian and Laird random effects model and the Mantel-Haenszel-Peto fixed effects model. Meta-Analyst 0.998 software (J. Lau, New England Medical Center, Boston, MA) was used to determine risk ratios (RRs) with 95% confidence intervals (CIs) of mortality and hospitalization for patients receiving care through these specialized programs compared with those receiving usual care. The Cochran Q test was used to test heterogeneity among the studies, and sensitivity analyses were performed to examine the effect of various covariates, such as duration of intervention, and other characteristics of the disease-management programs. RESULTS: The original search resulted in 416 published articles, of which 35 met preliminary selection criteria. Of these, 11 were randomized trials and were selected for the meta-analysis. Studies that were not randomized trials, did not involve heart failure patients or disease-management programs, or had missing outcomes were excluded. Of the 11 studies selected, nine involved specialized follow-up using multidisciplinary teams and the remaining two involved follow-up by primary care physicians and telephone. These studies involved 1,937 heart failure patients with a mean age of 74. The follow-up period ranged from no follow-up (one study) to 1 year (one study). Patients receiving care from specialized heart failure disease-management programs had a 13% lower risk of hospitalization than those receiving usual care (summary RR = 0.87; 95% CI = 0.79,0.96), but the Cochran Q test demonstrated significant heterogeneity among the studies (P = .003). Subgroup analysis of the nine studies using specialized follow-up by a multidisciplinary team showed similar results (summary RR = 0.77, 95% CI = 0.68,0.86; test of heterogeneity, P> .50). Seven of the nine studies did not show any significant association between intervention and reduced hospitalization, but the two studies that used follow up by primary care physicians and telephone failed to show any significant reduction in hospitalization (summary RR = 0.94, 95% CI = 0.75,1.19). In fact, one of the studies demonstrated a higher risk of hospitalization for patients receiving intervention (RR = 1.26, 95% CI = 1.04,1.52). Of the 11 studies, only six reported mortality as an outcome. None of these studies found any association between intervention and mortality (summary RR = 1.15, 95% CI = 0.96,1.37; test of heterogeneity, P> .15). Five of the studies used quality of life or functional status as outcomes, and, of them, only one demonstrated significant positive association. The results of the sensitivity analyses were negative for any significant association with duration of intervention or follow-up or year of study. Eight studies performed cost analyses and seven demonstrated cost-effectiveness of the intervention. CONCLUSIONS: The authors concluded that specialized disease-management programs were cost-effective, and heart failure patients cared for by these programs were more likely to undergo fewer hospitalizations, but the study did not provide any conclusive association between these programs and quality of care or mortality. The authors recommend that disease-management programs involve patient education and specialized follow-up by a multidisciplinary team including home health care. [source] Risk Stratification of Individuals with the Brugada Electrocardiogram: A Meta-AnalysisJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2006ANIL K. GEHI M.D. Objectives: We performed a meta-analysis of prognostic studies of patients with a Brugada ECG to assess predictors of events. Background: The Brugada syndrome is an increasingly recognized cause of idiopathic ventricular fibrillation; however, there is wide variation in the prognosis of patients with the Brugada ECG. Methods and Results: We retrieved 30 prospective studies of patients with the Brugada ECG, accumulating data on 1,545 patients. Summary estimates of the relative risk (RR) of events (sudden cardiac death [SCD], syncope, or internal defibrillator shock) for a variety of potential predictors were made using a random-effects model. The overall event rate at an average of 32 months follow-up was 10.0% (95% CI 8.5%, 11.5%). The RR of an event was increased (P < 0.001) among patients with a history of syncope or SCD (RR 3.24 [95% CI 2.13, 4.93]), men compared with women (RR 3.47 [95% CI 1.58, 7.63]), and patients with a spontaneous compared with sodium-channel blocker induced Type I Brugada ECG (RR 4.65 [95% CI 2.25, 9.58]). The RR of events was not significantly increased in patients with a family history of SCD (P = 0.97) or a mutation of the SCN5A gene (P = 0.18). The RR of events was also not significantly increased in patients inducible compared with noninducible by electrophysiologic study (EPS) (RR 1.88 [95% CI 0.62, 5.73], P = 0.27); however, there was significant heterogeneity of the studies included. Conclusions: Our findings suggest that a history of syncope or SCD, the presence of a spontaneous Type I Brugada ECG, and male gender predict a more malignant natural history. Our findings do not support the use of a family history of SCD, the presence of an SCN5A gene mutation, or EPS to guide the management of patients with a Brugada ECG. [source] A subpopulation of mesenchymal stromal cells with high osteogenic potentialJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009Hua Liu Abstract Current bone disease therapy with bone marrow-derived mesenchymal stromal cells (MSC) is hampered by low efficiency. Advanced allogeneic studies on well-established mouse genetic and disease models are hindered by difficulties in isolating murine MSC (mMSC). And mMSC prepared from different laboratories exhibit significant heterogeneity. Hence, this study aimed to identify and isolate a sub-population of mMSC at an early passage number with high osteogenic potential. Enrichment of mMSC was achieved by 1-hr silica incubation and negative selection. Approximately 96% of these cells synthesized osteocalcin after 28 days of osteogenic induction in vitro, and displayed a complete dynamic alteration of alkaline phosphatase (ALP) activity with increasing osteogenic maturation and strong mineralization. Moreover, the cells displayed uniform and stable surface molecular profile, long-term survival, fast proliferation in vitro with maintenance of normal karyotype and distinct immunological properties. CD73 was found to be expressed exclusively in osteogenesis but not in adipogenesis. These cells also retained high osteogenic potential upon allogeneic transplantation in an ectopic site by the detection of bone-specific ALP, osteopontin, osteocalcin and local mineralization as early as 12 days after implantation. Hence, these cells may provide a useful source for improving current strategies in bone regenerative therapy, and for characterizing markers defining the putative MSC population. [source] Study of V1a vasopressin receptor gene single nucleotide polymorphisms in platelet vasopressin responsivenessJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2006Kazi N. Hasan Abstract There is a significant heterogeneity among individuals in terms of platelet aggregation response to arginine vasopressin (AVP). The aim of this study was to evaluate whether four single nucleotide polymorphisms (SNPs) in the promoter region of vasopressin V1a receptor gene (V1aR) could be used as genetic markers for divergent platelet aggregation response to AVP. Seventeen of 33 subjects showed more than 60% of maximum platelet aggregation and were classified as responders. Sixteen were classified as nonresponders because they had less than 30% aggregation. In a preliminary study, V1aR gene sequences were determined in two responders and two nonresponders. We found four SNPs in the promoter region of the V1aR gene: ,6951G/A, ,4112A/T, ,3860T/C, and ,242C/T. In all 33 subjects the genotypes of four SNPs were determined using either polymerase chain reaction (PCR) with allele-specific primers or PCR followed by restriction-fragment length polymorphism (RFLP). There were no differences in the AVP-induced aggregation between the subjects with and without variant alleles of each four SNPs. The genotype frequencies of four SNPs of V1aR were almost identical between AVP responders and nonresponders. These results suggest that the four SNPs in the promoter region of the V1aR gene may not be useful as genetic markers for platelet aggregation heterogeneity. J. Clin. Lab. Anal. 20:87,92, 2006. © 2006 Wiley-Liss, Inc. [source] A systematic review of health-related quality of life instruments used for people with venous ulcers: an assessment of their suitability and psychometric propertiesJOURNAL OF CLINICAL NURSING, Issue 19-20 2010Simon J Palfreyman Aims and objectives., To review the quality of life questionnaires used to measure the impact of venous ulceration and to evaluate their psychometric properties. Background., Venous leg ulcers have a negative impact on quality of life. Health-related quality of life can be measured using structured questionnaires. Nurses are the primary care providers for patients with venous ulceration and are ideally placed to assess and develop these types of questionnaires. There may also be an opportunity to use such quality of life instruments to measure the impact of nursing interventions in other areas where nurses are the key care providers. Design., Systematic review. Method., Studies were sought that used quality of life instruments to evaluate the impact of venous ulceration. Fourteen electronic bibliographical databases and 11 Internet-based health services research related resources were searched. In addition, grey literature was sought and the reference lists of relevant articles checked. Data were extracted regarding the type of instrument used, sample, number of items and domains and psychometric performance of the instrument. Results., The initial search identified a total of 338 potential citations. After review, a total of 31 studies were included: 17 used generic and 14 used disease-specific instruments. Five different types of generic and seven disease-specific instruments were identified. There was significant heterogeneity between the studies in terms of study design, aetiology of ulceration and times of assessment. The disease-specific instruments showed limitations in relation to their applicability to venous ulcer patients because of flaws in design or validation. Conclusions., The literature on quality of life related to venous ulceration failed to sufficiently distinguish between those with different causes of leg ulceration. There appeared to be problems with the ability of current quality of life instruments to detect changes in quality of life related to ulcer healing. Relevance to clinical practice., There appears to be an opportunity for nurses to develop a health-related quality of life health-related quality of life instruments to evaluate their impact on patient outcomes. Such instruments could potentially allow nursing interventions to be assessed more effectively than the recently proposed nursing metrics. [source] Spatial and spectral heterogeneity of time-varying shear stress profiles in the carotid bifurcation by phase-contrast MRIJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2006Bradley D. Gelfand BSE Abstract Purpose To determine the heterogeneity of the time-varying shear stress profiles in the human carotid bifurcation, a region prone to atherosclerosis. Materials and Methods Lagrangian bicubic interpolation of phase-contrast MRI images was used to determine the shear stress profiles for three adult healthy male volunteers. Frequency spectra for the common and internal carotid artery (CCA and ICA, respectively)-derived shear stresses were examined in order to determine the presence of significant heterogeneity in the intensity distribution. Results Hemodynamic characteristics (peak, minimum, average shear stress, and oscillatory shear index [OSI]) were highly heterogeneous both along the length of the vessel as well as circumferentially around the CCA and ICA. In the frequency domain, intensities below 4 Hz were significantly higher in the CCA compared to the sinus region of the ICA, indicating that shear stress heterogeneity can be detected in the frequency domain. The harmonic index, a measure of the relative contributions of dynamic and static components of the shear stress signal, colocalizes with OSI, which implies a relationship between specific frequency components and atherosclerosis development. Conclusion These findings indicate that the time and frequency dependent parameters of in vivo shear stress have important implications for regional development of atherosclerosis. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc. [source] Oxidation Behavior of Zirconium Diboride Silicon Carbide Produced by the Spark Plasma Sintering MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2009Carmen M. Carney Dense samples of ZrB2,20 vol% SiC were successfully fabricated by spark plasma sintering without the use of sintering aids. Oxidation behavior of these samples was characterized by exposing them to 1400°, 1500°, and 1600°C in an ambient atmosphere for 150 min, and by measuring the weight gains of the sample and crucible, as well as the thickness of the oxide scale and the glassy outer layer. The effects of gravity on the viscous outer layer are shown to result in significant heterogeneity within a sample. The oxidation scales were characterized by scanning electron microscopy and transmission electron microscopy with energy dispersive spectroscopy analysis. The oxide scale was found to be composed of three layers: (1) a SiO2 -rich glassy outer layer, (2) an intermediate layer of a ZrO2 matrix with interpenetrating SiO2, and (3) a layer containing a ZrO2 matrix enclosing partially oxidized ZrB2 with Si,C,B,O glass inclusions. [source] Systematic review: self-management support interventions for irritable bowel syndromeALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2010S. D. Dorn Aliment Pharmacol Ther 2010; 32: 513,521 Summary Background, Irritable bowel syndrome is an extremely common and costly condition. Because there is no cure, patients must be supported to manage their own condition. Aim, To assess systematically the interventions used to support irritable bowel syndrome patient self-management. Methods, A search of PubMed, EMBASE, CINAHL and PsycINFO was performed to identify all studies that involved self-management support interventions for irritable bowel syndrome. Studies that compared the self-management-related intervention to a control group were included. Results, Eleven studies that involved a total of 1657 patients were included. For nearly all studies, the intervention was associated with statistically significant benefits. However, across studies there was significant heterogeneity in terms of sample size, diagnostic criteria, study setting, study design, primary outcome, statistical analyses and study quality. Therefore, individual study results could not be statistically combined. Conclusions, Many self-management support interventions appear benefit patients with irritable bowel syndrome. However, studies were limited by methodological flaws. Furthermore, feasibility in ,real world' clinical practice is uncertain. Thus, practical self-management interventions that can be applied across various clinical settings should be developed, and then tested in well-designed clinical trials. [source] Meta-analysis: proton pump inhibitor use and the risk of community-acquired pneumoniaALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 11 2010J. JOHNSTONE Aliment Pharmacol Ther,31, 1165,1177 Summary Background, Observational studies examining the association between proton pump inhibitor (PPI) use and risk of community-acquired pneumonia are conflicting. Aim, To assess systematically the association between risk of community-acquired pneumonia and PPI use in adults. Methods, We searched MEDLINE, EMBASE and CINAHL databases between 1988 and January 2010. Two reviewers independently selected studies based on eligibility criteria and extracted data. Included studies evaluated adults (,18 years) who took PPIs as an out-patient. The primary outcome was community-acquired pneumonia. Only observational studies with a comparison arm were included. Results, Over 2600 citations were reviewed. Six studies were included. All were nested case-control studies. Meta-analysis found an increased risk of community-acquired pneumonia associated with PPI use [OR 1.36 (95% CI 1.12,1.65)]; significant heterogeneity remained (I2 92%, P < 0.001). In exploratory subgroup analysis, short duration of use was associated with an increased odds of community-acquired pneumonia [OR 1.92 (95% CI 1.40,2.63), I2 75%, P = 0.003], whereas chronic use was not [OR 1.11 (95% CI 0.90,1.38), I2 91%, P < 0.001], a significant interaction (P < 0.005). Conclusions, Heterogeneity precluded interpretation of the summary statistic. Exploratory analysis revealed that duration of PPI use may impact the risk of community-acquired pneumonia, a finding that should be explored in future studies. [source] Genetic and Environmental Risk Indicators in Canine Non-Hodgkin's Lymphomas: Breed Associations and Geographic Distribution of 608 Cases Diagnosed throughout France over 1 YearJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2009M. Pastor Background: The etiology of non-Hodgkin's lymphomas (NHL) is multifactorial. Environmental and genetic factors are frequently incriminated both in humans and dogs. Objectives: Our purpose was to study the geographic distribution of canine NHL (CNHL) in France and to evaluate genetic and environmental influences. Animals: Six hundred and eight cases of CNHL, diagnosed throughout France over 1 year, were collected from 7 Veterinary Histopathologic Laboratories. Methods: Retrospective study. Breeds affected by lymphomas were compared with the national population and associations between breed and immunophenotype were studied. The distribution of CNHL and canine T-cell NHL per 100,000 dogs per department was compared with the distribution of waste incinerators, polluted sites, and radioactive waste. Results: The breeds significantly overrepresented among lymphoma cases were Boxer, Setter, and Cocker Spaniel (P < .001). There was a significant association between Boxer and T-cell NHL (P < .001), and between German Shepherd and Rottweiler and B-cell NHL (P < .01). The geographic distribution of CNHL and canine T-cell NHL indicated significant heterogeneity. Significant association between distributions of CNHL and waste incinerators (,= 0.25, P < .05), polluted sites (,= 0.36, P < .001), and radioactive waste (,= 0.51, P < .001) was found. Conclusions and Clinical Importance: Influence of genetics in the development of CNHL was supported by the existence of an association between breed and immunophenotype. Waste incinerators, polluted sites, and radioactive waste could just be considered as risk indicators of CNHL, but not as risk factors. Case-control studies around critical sites are necessary to confirm the implication of those environmental factors in the development of CNHL. [source] Systematic review and meta-analysis: enhanced efficacy of proton-pump inhibitor therapy for peptic ulcer bleeding in Asia , a post hoc analysis from the Cochrane CollaborationALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 9 2005G. I. Leontiadis Summary Background :,Proton-pump inhibitors reduce re-bleeding rates after ulcer bleeding. However, there is significant heterogeneity among different randomized-controlled trials. Aim :,To see whether proton-pump inhibitors for ulcer bleeding produced different clinical outcomes in different geographical locations. Methods :,This was a post hoc analysis of our Cochrane Collaboration systematic review and meta-analysis of proton-pump inhibitor therapy for ulcer bleeding. Sixteen randomized-controlled trials conducted in Europe and North America were pooled and re-analysed separately from seven conducted in Asia. We calculated pooled rates for 30-day all-cause mortality, re-bleeding and surgical intervention and derived odds ratios and numbers needed to treat with 95% confidence intervals. Results :,There was no significant heterogeneity for any outcome. Reduced all-cause mortality was seen in the Asian randomized-controlled trials (odds ratios = 0.35; 95% confidence interval: 0.16,0.74; number needed to treat = 33), but not in the others (odds ratios =,1.36; 95% confidence interval: 0.94,1.96; number needed to treat , incalculable). There were significant reductions in re-bleeding and surgery in both sets of randomized-controlled trials, but the effects were quantitatively greater in Asia. Conclusions :,Proton-pump inhibitor therapy for ulcer bleeding has been more efficacious in Asia than elsewhere. This may be because of an enhanced pharmacodynamic effect of proton-pump inhibitors in Asian patients. [source] Omega 3 and 6 oils for primary prevention of allergic disease: systematic review and meta-analysisALLERGY, Issue 6 2009C. Anandan Background:, There is conflicting evidence on the use of omega 3 and omega 6 supplementation for the prevention of allergic diseases. We conducted a systematic review evaluating the effectiveness of omega 3 and 6 oils for the primary prevention of sensitization and development of allergic disorders. Methods:, We searched The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, LILACS, PsycInfo, AMED, ISI Web of Science and Google Scholar for double-blind randomized controlled trials. Two authors independently assessed articles for inclusion. Meta-analyses were undertaken using fixed effects modelling, or random effects modelling in the event of detecting significant heterogeneity. Results:, Of the 3129 articles identified, 10 reports (representing six unique studies) satisfied the inclusion criteria. Four studies compared omega 3 supplements with placebo and two studies compared omega 6 supplements with placebo. There was no clear evidence of benefit in relation to reduced risk of allergic sensitization or a favourable immunological profile. Meta-analyses failed to identify any consistent or clear benefits associated with use of omega 3 [atopic eczema: RR = 1.10 (95% CI 0.78,1.54); asthma: RR = 0.81 (95% CI 0.53,1.25); allergic rhinitis: RR = 0.80 (95% CI 0.34,1.89) or food allergy RR = 0.51 (95% CI 0.10,2.55)] or omega 6 oils [atopic eczema: RR = 0.80 (95% CI 0.56,1.16)] for the prevention of clinical disease. Conclusions:, Contrary to the evidence from basic science and epidemiological studies, our systematic review and meta-analysis suggests that supplementation with omega 3 and omega 6 oils is probably unlikely to play an important role as a strategy for the primary prevention of sensitization or allergic disease. [source] Prescribing patterns of antiparkinsonian agents in Europe,MOVEMENT DISORDERS, Issue 8 2010Mário Miguel Rosa MD Abstract In the 1990s, previous knowledge and randomized controlled trials supported the establishment of today's therapeutic recommendations in Parkinson's disease (PD). Scientific evidence allows different options for the treatment of PD. Patterns of use of antiparkinsonian agents (APA) across European countries may thus reflect these options. We wanted to describe patterns of use of APA in Europe and characterize the changes in prescription habits between 2003 and 2007. We investigated APA outpatient sales in 26 European countries where all commercially available APA were studied. Data for molecules and brand names were collected through IMS Health. Treatment per 1000 inhabitants daily (DID) was obtained from the WHO defined daily dose. Prescription pattern changes were evaluated by market share. Prescription patterns varied widely. In most countries, levodopa/dopamine agonists accounted for half of the drug use; whereas in others, anticholinergics, MAO inhibitors and amantadine prevailed. The greatest increase occurred with monoamine oxidase inhibitors and levodopa. There was an increase in dopamine agonists and a decrease in anticholinergics. For a 6.8% dose consume increase, there was a 41.1% sales increase (in euros). We showed an increase in the consumption of APA over 5 years. There was significant heterogeneity in the use of APA in Europe, suggesting differences in drug treatment. Costs of medication increased more than did dose consume, implying an increase in the cost of individual patient treatment. Published evidence does not explain the observed differences in the prescribing of APA. © 2010 Movement Disorder Society [source] | |||||||||||||||||||||||||