25 resultados para Crossover designs
em Scielo Saúde Pública - SP
Resumo:
The recommended treatment for latent tuberculosis (TB) infection in adults is a daily dose of isoniazid (INH) 300 mg for six months. In Brazil, INH was formulated as 100 mg tablets. The treatment duration and the high pill burden compromised patient adherence to the treatment. The Brazilian National Programme for Tuberculosis requested a new 300 mg INH formulation. The aim of our study was to compare the bioavailability of the new INH 300 mg formulation and three 100 mg tablets of the reference formulation. We conducted a randomised, single dose, open label, two-phase crossover bioequivalence study in 28 healthy human volunteers. The 90% confidence interval for the INH maximum concentration of drug observed in plasma and area under the plasma concentration vs. time curve from time zero to the last measurable concentration “time t” was 89.61-115.92 and 94.82-119.44, respectively. The main limitation of our study was that neither adherence nor the safety profile of multiple doses was evaluated. To determine the level of INH in human plasma, we developed and validated a sensitive, simple and rapid high-performance liquid chromatography-tandem mass spectrometry method. Our results showed that the new formulation was bioequivalent to the 100 mg reference product. This finding supports the use of a single 300 mg tablet daily strategy to treat latent TB. This new formulation may increase patients’ adherence to the treatment and quality of life.
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Orchid bees are increasingly applied on Neotropical biomonitoring and bioindication studies due to the relative easiness of sampling and identification when compared to other bee groups. A considerable number of orchid bee community studies have been adopting baited traps as a sampling method, especially for replication purposes. However, the trap attributes are variable, and hitherto no evaluation of different designs was carried out. Here, five attributes of baited traps were tested: trap volume, number of entrance holes, presence of landing platform, kind of landing platform, and fixation content. We use Mann-Whitney tests to access differences in richness and abundance capture rates for each trap design. We found that volume, number of entrance holes, and fixation content do not influence orchid bees capture. However, the design without landing platforms had a significantly higher capture rate for richness when compared with sanded landing platforms. On the other hand, analyzing the kind of landing platform, we detected a significantly higher richness and abundance for the trap with landing platforms glued with sand. Despite the fact that the effects of different designs tested here were very punctual, we consider that results from samples taken with different baited trap designs are comparable. Some adjustments on trap design can be done according to the particularities of future studies.
Resumo:
The objective of this work was to compare the relative efficiency of initial selection and genetic parameter estimation, using augmented blocks design (ABD), augmented blocks twice replicated design (DABD) and group of randomised block design experiments with common treatments (ERBCT), by simulations, considering fixed effect model and mixed model with regular treatment effects as random. For the simulations, eight different conditions (scenarios) were considered. From the 600 simulations in each scenario, the mean percentage selection coincidence, the Pearsons´s correlation estimates between adjusted means for the fixed effects model, and the heritability estimates for the mixed model were evaluated. DABD and ERBCT were very similar in their comparisons and slightly superior to ABD. Considering the initial stages of selection in a plant breeding program, ABD is a good alternative for selecting superior genotypes, although none of the designs had been effective to estimate heritability in all the different scenarios evaluated.
Resumo:
The optimization of the anaerobic degradation of the azo dye Remazol golden yellow RNL was performed according to multivariate experimental designs: a 2² full-factorial design and a central composite design (CCD). The CCD revealed that the best incubation conditions (90% color removal) for the degradation of the azo dye (50 mg L- 1) were achieved with 350 mg L- 1 of yeast extract and 45 mL of anaerobic supernatant (free cell extract) produced from the incubation of 650 mg L- 1 of anaerobic microorganisms and 250 mg L- 1 of glucose. A first-order kinetics model best fit the experimental data (k = 0.0837 h- 1, R² = 0.9263).
Resumo:
Our objective was to evaluate the effectiveness of a long-acting formulation of methylphenidate (MPH-SODAS) on attention-deficit/hyperactivity disorder (ADHD) symptoms in an outpatient sample of adolescents with ADHD and substance use disorders (SUD). Secondary goals were to evaluate the tolerability and impact on drug use of MPH-SODAS. This was a 6-week, single-blind, placebo-controlled crossover study assessing efficacy of escalated doses of MPH-SODAS on ADHD symptoms in 16 adolescents with ADHD/SUD. Participants were randomly allocated to either group A (weeks 1-3 on MPH-SODAS, weeks 4-6 on placebo) or group B (reverse order). The primary outcome measures were the Swanson, Nolan and Pelham Scale, version IV (SNAP-IV) and the Clinical Global Impression Scale (CGI). We also evaluated the adverse effects of MPH-SODAS using the Barkley Side Effect Rating Scale and subject reports of drug use during the study. The sample consisted of marijuana (N = 16; 100%) and cocaine users (N = 7; 43.8%). Subjects had a significantly greater reduction in SNAP-IV and CGI scores (P < 0.001 for all analyses) during MPH-SODAS treatment compared to placebo. No significant effects for period or sequence were found in analyses with the SNAP-IV and CGI scales. There was no significant effect on drug use. MPH-SODAS was well tolerated but was associated with more severe appetite reduction than placebo (P < 0.001). MPH-SODAS was more effective than placebo in reducing ADHD symptoms in a non-abstinent outpatient sample of adolescents with comorbid SUD. Randomized clinical trials, with larger samples and SUD intervention, are recommended.
Resumo:
O uso de próteses auditivas é uma boa opção para melhorar o zumbido e a perda de audição. OBJETIVO: Avaliar a resposta do zumbido à prótese retroauricular com molde aberto e com ventilação de alívio em pacientes com perda auditiva neurossensorial simétrica após um mês de uso. CASUÍSTICA E MÉTODOS: 50 pacientes atendidos no Grupo de Pesquisa em Zumbido com zumbido e perda auditiva bilateral foram submetidos a um ensaio clínico randomizado cego crossover: 26 pacientes iniciaram o ensaio utilizando molde aberto e 24 iniciaram usando ventilação de alívio. Após 30 dias de teste com o primeiro tipo de molde e um período de wash-out, o tipo de molde foi trocado e o segundo foi usado por 30 dias. O zumbido foi avaliado de modo qualitativo (melhora, inalterado e piora) e quantitativo (variação de 0 a 10 de uma escala numérica). RESULTADOS: 82% dos casos melhoraram do zumbido com pelo menos um tipo de molde e não houve diferença significante na diminuição do incômodo com o zumbido nas avaliações qualitativa e quantitativa com ambos os moldes. Entretanto 66% dos pacientes preferiram o molde aberto. CONCLUSÃO: A curto prazo, a melhora do zumbido com a prótese auditiva não depende do tamanho da ventilação do molde.
Resumo:
Abstract This article provides a comprehensive picture of IR in South America by applying content analysis to 7,857 articles published in 35 journals from six South American countries from 2006 to 2014 in order to discover what the predominant theories, methods and research areas in this field are, how scholars tend to combine them in their research designs, and what the profiles of regional journals are, regarding their epistemological, methodological and subject preferences. The findings reveal a predominantly Positivist and largely Qualitative discipline, resembling North American and European IR.
Resumo:
Papers on child-care attendance as a risk factor for acute respiratory infections and diarrhea were reviewed. There was great variety among the studies with regard to the design, definition of exposure and definition of outcomes. All the traditional epidemiological study designs have been used. The studies varied in terms of how child-care attendance in general was defined, and for different settings. These definitions differed especially in relation to the minimum time of attendance required. The outcomes were also defined and measured in several different ways. The analyses performed were not always appropriate, leading to sets of results of uneven quality, and composed of different measures of association relating different exposures and outcomes, that made summarizing difficult. Despite that, the results reported were remarkably consistent. Only two of the papers reviewed failed to show some association between child-care attendance and increased acute respiratory infections, or diarrhea. On the other hand, the magnitude of the associations reported varied widely, especially for lower respiratory infections. Taken together, the studies so far published provide evidence that children attending child-care centers, especially those under three years of age, are at a higher risk of upper respiratory infections, lower respiratory infections, and diarrhea. The studies were not consistent, however, in relation to attendance at child-care homes. Children in such settings were sometimes similar to those in child-care centers, sometimes similar to those cared for at home, and sometimes presented an intermediate risk.
Resumo:
There are complex and diverse methodological problems involved in the clinical and epidemiological study of respiratory diseases and their etiological factors. The association of urban growth, industrialization and environmental deterioration with respiratory diseases makes it necessary to pay more attention to this research area with a multidisciplinary approach. Appropriate study designs and statistical techniques to analyze and improve our understanding of the pathological events and their causes must be implemented to reduce the growing morbidity and mortality through better preventive actions and health programs. The objective of the article is to review the most common methodological problems in this research area and to present the most available statistical tools used.
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Individual cancer susceptibility seems to be related to factors such as changes in oncogenes and tumor suppressor genes expression, and differences in the action of metabolic enzymes and DNA repair regulated by specific genes. Epidemiological studies on genetic polymorphisms of human xenobiotics metabolizing enzymes and cancer have revealed low relative risks. Research considering genetic polymorphisms prevalence jointly with environmental exposures could be relevant for a better understanding of cancer etiology and the mechanisms of carcinogenesis and also for new insights on cancer prognosis. This study reviews the approaches of molecular epidemiology in cancer research, stressing case-control and cohort designs involving genetic polymorphisms, and factors that could introduce bias and confounding in these studies. Similarly to classical epidemiological research, genetic polymorphisms requires considering aspects of precision and accuracy in the study design.
Resumo:
OBJETIVO: Analisar o efeito do tratamento nutricional sobre as alterações metabólicas provocadas pelo uso da terapia antirretroviral em adultos vivendo com HIV/aids. MÉTODOS: Revisão sistemática de literatura no PubMed, Lilacs e Cochrane, entre 1996 e 2010, do tipo ensaio clínico, controlado, randomizado, crossover, adultos, vivendo com HIV/aids em uso de terapia antirretroviral e sem doenças oportunistas. A intervenção de interesse foi suplementação nutricional via oral e/ou mudança de estilo de vida por tratamento dietoterápico específico: dislipidemia, resistência insulínica, lipodistrofia e hipertensão arterial sistêmica. A escala de Jadad foi utilizada para classificação qualitativa dos artigos. RESULTADOS: Foram localizados 385 artigos e sete foram incluídos. As intervenções utilizadas nesses estudos foram: dieta, dieta mais exercício físico, dieta mais suplemento e somente suplementos. Dislipidemia foi desfecho avaliado em todos os estudos. Os estudos que avaliaram suplementação com ômega 3 encontraram redução significativa dos triglicérides. Dieta específica mais suplementação de ômega 3 mostrou aumento de HDL-colesterol. Suplementação com nicotinato de cromo não teve efeito sobre a dislipidemia. Modificação de estilo de vida, incluindo dieta e atividade física, reduziu significativamente a circunferência da cintura, lipodistrofia e pressão arterial sistólica. CONCLUSÕES: A redução de triglicérides pela suplementação com ômega 3 foi a intervenção nutricional com maiores evidências científicas. A prescrição de dieta específica parece ser a intervenção mais adequada para aumentar HDL-colesterol. Não é possível fazer inferências sobre o tratamento nutricional do colesterol total, LDL-colesterol e resistência insulínica. Modificações no estilo de vida podem promover melhora da lipodistrofia e pressão arterial.
Resumo:
OBJECTIVE To analyze the effect of air pollution and temperature on mortality due to cardiovascular and respiratory diseases. METHODS We evaluated the isolated and synergistic effects of temperature and particulate matter with aerodynamic diameter < 10 µm (PM10) on the mortality of individuals > 40 years old due to cardiovascular disease and that of individuals > 60 years old due to respiratory diseases in Sao Paulo, SP, Southeastern Brazil, between 1998 and 2008. Three methodologies were used to evaluate the isolated association: time-series analysis using Poisson regression model, bidirectional case-crossover analysis matched by period, and case-crossover analysis matched by the confounding factor, i.e., average temperature or pollutant concentration. The graphical representation of the response surface, generated by the interaction term between these factors added to the Poisson regression model, was interpreted to evaluate the synergistic effect of the risk factors. RESULTS No differences were observed between the results of the case-crossover and time-series analyses. The percentage change in the relative risk of cardiovascular and respiratory mortality was 0.85% (0.45;1.25) and 1.60% (0.74;2.46), respectively, due to an increase of 10 μg/m3 in the PM10 concentration. The pattern of correlation of the temperature with cardiovascular mortality was U-shaped and that with respiratory mortality was J-shaped, indicating an increased relative risk at high temperatures. The values for the interaction term indicated a higher relative risk for cardiovascular and respiratory mortalities at low temperatures and high temperatures, respectively, when the pollution levels reached approximately 60 μg/m3. CONCLUSIONS The positive association standardized in the Poisson regression model for pollutant concentration is not confounded by temperature, and the effect of temperature is not confounded by the pollutant levels in the time-series analysis. The simultaneous exposure to different levels of environmental factors can create synergistic effects that are as disturbing as those caused by extreme concentrations.
Resumo:
ABSTRACT OBJECTIVE To analyze the scientific literature about the effects of exposure to psychosocial risk factors in work contexts. METHODS A systematic review was performed using the terms “psychosocial factors” AND “COPSOQ” in the databases PubMed, Medline, and Scopus. The period analyzed was from January 1, 2004 to June 30, 2012. We have included articles that used the Copenhagen Psychosocial Questionnaire (COPSOQ) as a measuring instrument of the psychosocial factors and the presentation of quantitative or qualitative results. German articles, psychometric studies or studies that did not analyze individual or work factors were excluded. RESULTS We included 22 articles in the analysis. Individual factors, such as gender, age, and socioeconomic status, were analyzed along with work-related factors such as labor demands, work organization and content, social relationships and leadership, work-individual interface, workplace values, justice and respect, personality, health and well-being, and offensive behaviors. We analyzed the sample type and the applied experimental designs. Some population groups, such as young people and migrants, are more vulnerable. The deteriorated working psychosocial environment is associated with physical health indicators and weak mental health. This environment is also a risk factor for the development of moderate to severe clinical conditions, predicting absenteeism or intention of leaving the job. CONCLUSIONS The literature shows the contribution of exposure to psychosocial risk factors in work environments and their impact on mental health and well-being of workers. It allows the design of practical interventions in the work context to be based on scientific evidences. Investigations in specific populations, such as industry, and studies with more robust designs are lacking.
Resumo:
The incidence of vasal injury during inguinal herniorrhaphy is estimated at 0.5%. We sought to assess the patency rates and long-term fertility outcome after microsurgical repair of vasal obstruction related to prior inguinal herniorrhaphy. METHODS: Twenty procedures were performed on 13 men diagnosed with infertility and vasal injury secondary to previous inguinal herniorrhaphy. Eight of these men had undergone bilateral and 5 unilateral inguinal herniorrhaphy. Twelve procedures were vasovasostomies, 3 were crossover vasovasostomies, 2 were vasoepididymostomies, and 3 were crossover vasoepididymostomies. Eight patients were azoospermic, 2 were severely oligospermic (<1 M/mL), 1 was oligospermic, and 2 were asthenospermic. Patency data was obtained on all 13 patients, and pregnancy data was available for 10 couples (77%), with a mean follow-up of 69.5 months. RESULTS: The overall patency rate was 65%. In the vasovasostomy group, the patency rate was 60% (9/15), and in the vasoepididymostomy group it was 80% (4/5). Among the azoospermic patients, 13 procedures were performed. The patency rate was 42.9% for the vasovasostomy (3/7), and 100% for the vasoepididymostomy procedure (4/4). The overall pregnancy rate was 40%. Of the men who underwent vasoepididymostomy, 80% (4/5) established a pregnancy. CONCLUSIONS: Microsurgical vasovasostomy after inguinal vas injury results in a reasonable patency rate but a lower pregnancy rate than that after vasectomy reversal. When microsurgical vasoepididymostomy was possible, it resulted in high patency and pregnancy rate. Crossover vasoepididymostomy, when appropriate, can be a useful alternative to inguinal vasovasostomy.
Resumo:
PURPOSE: To investigate whether bethanecol chloride may be an alternative for the clinical management of clomipramine-induced orgasmic dysfunction, reported to occur in up to 96% of male users. METHODS: In this study, 12 fully remitted panic disorder patients, complaining of severe clomipramine-induced ejaculatory delay, were randomly assigned to either bethanecol chloride tablets (20 mg, as needed) or placebo in a randomized, double-blind, placebo-controlled, two-period crossover study. A visual analog scale was used to assess severity of the orgasmic dysfunction. RESULTS: A clear improvement was observed in the active treatment period. No placebo or carry-over effects were observed. CONCLUSION: These findings suggest that bethanecol chloride given 45 minutes before sexual intercourse may be useful for clomipramine-induced orgasmic dysfunction in males.