Roseli Aparecida Leandro

Total phenol concentrations in coffee tree leaves during fruit development

Vegetables have a natural defense against external factors synthesizing phenolic compounds, which depends on the maturity stage and on the climate. Total phenol grades were extracted from mature and young coffee leaves and were analyzed in relation to yield, phenology and climate. The climatic conditions were described by air temperature, global radiation and daily insolation. Evaluations were made on height, diameter and length of reproductive branches to determine the respective vegetative growth rates of the plants. The amounts of total phenols in the plants at the production stage was 174.0 mg g-1 and 138.9 mg g-1 for young and mature leaves, respectively, and for plants without fruit formation 186.5 mg g-1 and 127.6 mg g-1 for young and mature leaves, respectively. The total phenol concentrations in young leaves with and without fruit formation were 25% and 46% greater compared to mature leaves. The secondary phenol synthesis in seed (146.8 mg g-1) was 31% lower than during grain maturation (212.4 mg g-1). The total phenol metabolization depends indirectly on the temperature and on the global radiation, presenting an inverse trend in relation to these climatic variables. Crop protection management should take into consideration periods of endanger of this natural defense of the plant.

Use of Markov Chain Monte Carlo Methods in a Bayesian Analysis of the Block and Basu Bivariate Exponential Distribution

Metropolis algorithms along with Gibbs steps are proposed to perform a Bayesian analysis for the Block and Basu (ACBVE) bivariate exponential distribution. We also consider the use of Gibbs sampling to develop Bayesian inference for accelerated life tests assuming a power rule model and the ACBVE distribution. The methodology developed in this paper is exemplified with two examples.

Experimental power considerations—Justifying replication for animal care and use committees

A common practice in poultry science is to compare new treatments with a control or between treatments tested in planned experiments. The overall F-test from an ANOVA of the data allows the researcher to reject or not reject the null hypothesis. However, the correct conclusion from such analysis depends on sufficient replicates being included in the experiment. On the other hand, restrictions are imposed to reduce the number of birds used in experiments for welfare reasons and to save scarce resources. We review the basic concepts needed to determine the number of replicates before conducting an experiment. We use these concepts to assess the results of several real experiments and to show what might be done in future experiments. We describe how to do the computations in R software.

Systematic Review of Health Economic Evaluation Studies Developed in Brazil from 1980 to 2013

Background Brazil has sought to use economic evaluation to support healthcare decision-making processes. While a number of health economic evaluations (HEEs) have been conducted, no study has systematically reviewed the quality of Brazilian HEE. The objective of this systematic review was to provide an overview regarding the state of HEE research and to evaluate the number, characteristics, and quality of reporting of published HEE studies conducted in a Brazilian setting. Methods We systematically searched electronic databases (MEDLINE, EMBASE, Latin American, and Caribbean Literature on Health Sciences Database, Scientific Electronic Library Online, NHS Economic Evaluation Database, health technology assessment Database, Bireme, and Biblioteca Virtual em Saúde Economia da Saúde); citation indexes (SCOPUS, Web of Science), and Sistema de Informação da Rede Brasileira de Avaliação de Tecnologia em Saúde. Partial and full HEEs published between 1980 and 2013 that referred to a Brazilian setting were considered for inclusion. Results In total, 535 studies were included in the review, 36.8% of these were considered to be full HEE. The category of healthcare technologies more frequently assessed were procedures (34.8%) and drugs (28.8%) which main objective was treatment (72.1%). Forty-four percent of the studies reported their funding source and 36% reported a conflict of interest. Overall, the full HEE quality of reporting was satisfactory. But some items were generally poorly reported and significant improvement is required: (1) methods used to estimate healthcare resource use quantities and unit costs, (2) methods used to estimate utility values, (3) sources of funding, and (4) conflicts of interest. Conclusion A steady number of HEE have been published in Brazil since 1980. To improve their contribution to inform national healthcare policy efforts need to be made to enhance the quality of reporting of HEEs and promote improvements in the way HEEs are designed, implemented (i.e., using sound methods for HEEs) and reported.

Many Miles to Go: A Systematic Review of the State of Cost-Utility Analyses in Brazil

BackgroundLittle is known about the quality and quantity of cost-utility analyses (CUAs) in Brazil.ObjectiveThe objective of this study was to provide a systematic review of published CUAs of healthcare technologies in Brazil.MethodsWe performed a systematic review of economic evaluations studies published in MEDLINE, EMBASE, LILACS (Latin American and Caribbean Health Sciences Literature), SciELO (Scientific Electronic Library Online), NHS EED (National Health Service Economic Evaluation Database), HTA (Health Technology Assessment) Database, Web of Science, Scopus, Bireme (Biblioteca Regional de Medicina), BVS ECOS (Health Economics database of the Brazilian Virtual Library of Health), and SISREBRATS (Sistema de Informação da Rede Brasileira de Avaliação de Tecnologias em Saúde [Brazilian Network for the Evaluation of Health Technologies]) from 1980 to 2013. Articles were included if they were CUAs according to the classification devised by Drummond et al. Two independent reviewers screened articles for relevance and carried out data extraction. Disagreements were resolved through discussion or through consultation with a third reviewer. We performed a qualitative narrative synthesis.ResultsOf the 535 health economic evaluations (HEEs) relating to Brazil, only 40 were CUAs and therefore included in the analysis. Most studies adhered to methodological guidelines for quality of reporting and 77.5% used quality-adjusted life-years (QALYs) as the health outcome. Of these studies, 51.6% did not report the population used to elicit preferences for outcomes and 45.2% used a specific population such as expert opinion. The preference elicitation method was not reported in 58.1% of these studies. The majority (80.6%) of studies did not report the instrument used to derive health state valuations and no publication reported whether tariffs (or preference weights) were national or international. No study mentioned the methodology used to estimate QALYs.ConclusionsMany published Brazilian cost-utility studies adhere to key recommended general methods for HEE; however, the use of QALY calculations is far from being the current international standard. Development of health preferences research can contribute to quality improvement of health technology assessment reports in Brazil.

Economic evaluations in gastroenterology in Brazil: A systematic review

AIM To systematically review economic evaluations in gastroenterology, relating to Brazil, published between 1980 and 2013. METHODS We selected full and partial economic evaluations from among those retrieved by searching the following databases: MEDLINE (PubMed); Excerpta Medica; the Latin American and Caribbean Health Sciences Literature database; the Scientific Electronic Library Online; the database of the Centre for Reviews and Dissemination; the National Health Service (NHS) Economic Evaluation Database; the NHS Health Technology Assessment database; the Health Economics database of the Brazilian Virtual Library of Health; Scopus; Web of Science; and the Brazilian Network for the Evaluation of Health Technologies. Two researchers, working independently, selected the studies and extracted the data. RESULTS We identified 535 health economic evaluations relating to Brazil and published in the 1980-2013 period. Of those 535 articles, only 40 dealt with gastroenterology. Full and partial economic evaluations respectively accounted for 23 (57.5%) and 17 (42.5%) of the 40 studies included. Among the 23 full economic evaluations, there were 11 cost-utility analyses, seven cost-effectiveness analyses, four cost-consequence analyses, and one cost-minimization analysis. Of the 40 studies, 25 (62.5%) evaluated medications; 7 (17.5%) evaluated procedures; and 3 (7.5%) evaluated equipment. Most (55%) of the studies were related to viral hepatitis, and most (63.4%) were published after 2010. Other topics included gastrointestinal cancer, liver transplantation, digestive diseases and hernias. Over the 33-year period examined, the number of such economic evaluations relating to Brazil, especially of those evaluating medications for the treatment of hepatitis, increased considerably. CONCLUSION Further studies are needed in order to ensure that expenditures on health care in Brazil are made as fairly and efficiently as possible.

Double generalized linear model for tissue culture proportion data: A Bayesian perspective

Joint generalized linear models and double generalized linear models (DGLMs) were designed to model outcomes for which the variability can be explained using factors and/or covariates. When such factors operate, the usual normal regression models, which inherently exhibit constant variance, will under-represent variation in the data and hence may lead to erroneous inferences. For count and proportion data, such noise factors can generate a so-called overdispersion effect, and the use of binomial and Poisson models underestimates the variability and, consequently, incorrectly indicate significant effects. In this manuscript, we propose a DGLM from a Bayesian perspective, focusing on the case of proportion data, where the overdispersion can be modeled using a random effect that depends on some noise factors. The posterior joint density function was sampled using Monte Carlo Markov Chain algorithms, allowing inferences over the model parameters. An application to a data set on apple tissue culture is presented, for which it is shown that the Bayesian approach is quite feasible, even when limited prior information is available, thereby generating valuable insight for the researcher about its experimental results.

Uma abordagem bayesiana para o mapeamento de QTLS utilizando o método MCMC com saltos reversíveis

A utilizacao de metodologias bayesianas tem se tornado frequente nas aplicacoes em Genetica, em particular em mapeamento de QTLs usando marcadores moleculares. Mapear um QTL significa identificar sua localizacao ao longo do genoma, estimar seus efeitos geneticos: aditivo, dominância, epistasia, etc. A abordagem bayesiana permite combinar a verossimilhanca dos dados fenotipicos com distribuicoes a priori atribuidas a todas as quantidades desconhecidas no modelo (numero, localizacao no genoma e efeitos geneticos dos QTLs) de forma a fornecer distribuicoes a posteriori a respeito dessas quantidades. Metodos de mapeamento bayesiano podem incorporar a incerteza relativa ao numero desconhecido de QTLs na analise; essa incerteza, no entanto, resulta em complicacoes na obtencao da amostra da distribuicao conjunta a posteriori, uma vez que a dimensao do espaco do modelo pode variar. O metodo MCMC com Saltos Reversiveis (MCMC-SR), proposto por Green (1995), e uma excelente ferramenta para explorar a distribuicao conjunta a posteriori nesse contexto. Neste trabalho, explora-se o metodo MCMC-SR, utilizando dados artificiais gerados no software WinQTLCart, atribuindo-se diferentes prioris para o numero de QTLs.

Health Economic Evaluations of Cancer in Brazil: A Systematic Review

Background: A large number of health economic evaluation (HEE) studies have been published in developed countries. However, Brazilian HEE literature in oncology has not been studied. Objective: To investigate whether the scientific literature has provided a set of HEE in oncology capable of supporting decision making in the Brazilian context. Methods: A systematic review was conducted to identify and characterize studies in this field. We searched multiple databases selecting partial and full HEE studies in oncology (1998-2013). Results: Fifty-five articles were reviewed, of these, 33 (60%) were full health economic evaluations. Type of cancers most frequently studied were: breast (38.2%), cervical (14.6%), lung (10.9%) and colorectal (9.1%). Procedures (47.3%) were the technologies most frequently evaluated. In terms of the intended purposes of the technologies, most (63.6%) were treatments. The majority of the incremental cost-effectiveness ratios (ICERs) reported have been below the cost-effectiveness threshold suggested by the World Health Organization (WHO). Conclusions: There has been an increase in the number of HEEs related to cancer in Brazil. These studies may support decision-making processes regarding the coverage of and reimbursement of healthcare technologies for cancer treatment in Brazil.

A systematic review of health economic evaluations of vaccines in Brazil

ABSTRACT Background: In Brazil, since 2005, the Ministry of Health requires Health Economic Evaluation (HEE) of vaccines for introduction into the National Immunization Program. Objectives: To describe and analyze the full HEE on vaccines conducted in Brazil from 1980 to 2013. Methods: Systematic review of the literature. We searched multiple databases. Two researchers independently selected the studies and extracted the data. The methodological quality of individual studies was evaluated using CHEERS items. Results: Twenty studies were reviewed. The most evaluated vaccines were pneumococcal (25%) and HPV (15%). The most used types of HEE were cost-effectiveness analysis (45%) and cost-utility analysis (20%). The research question and compared strategies were stated in all 20 studies and the target population was clear in 95%. Nevertheless, many studies did not inform the perspective of analysis or data sources. Conclusions: HEE of vaccines in Brazil has increased since 2008. However, the studies still have methodological deficiencies.