Revisão sistemática e meta-análise de estudos de diagnóstico e prognóstico: um tutorial

As revisões sistemáticas com meta-análise de estudos de exames diagnósticos ou de fatores prognósticos são ferramentas de pesquisa ainda em fase de desenvolvimento. O objetivo do presente texto é descrever a metodologia de revisão sistemática e de meta-análise deste tipo de estudos, passo a passo. Foi feita a revisão da literatura sobre o tema, compilando as recomendações e organizando o texto em: a) Introdução, b) Setalhamento dos oito passos a serem seguidos, c) Forma de publicação da revisão sistemática com meta-análise e d) Conclusão. Foram descritos os métodos de revisão sistemática de forma detalhada, com análise crítica dos métodos de compilação estatística dos resultados, com ênfase na utilização da curva Summary Receiver Operator Characteristic. Forneceu-se referência para os detalhes de cada técnica estatística utilizada na meta-análise. Concluímos que as revisões sistemáticas com meta-análise de exames diagnósticos ou de fatores prognósticos são valiosas na compilação de dados de vários estudos sobre o mesmo tema, reduzindo vieses e aumentando o poder estatístico da pesquisa primária.

Antimalarial Drug Resistance: Surveillance and Molecular Methods for National Malaria Control Programmes

National malaria control programmes have the responsibility to develop a policy for malaria disease management based on a set of defined criteria as efficacy, side effects, costs and compliance. These will fluctuate over time and national guidelines will require periodic re-assessment and revision. Changing a drug policy is a major undertaking that can take several years before being fully operational. The standard methods on which a decision can be taken are the in vivo and the in vitro tests. The latter allow a quantitative measurement of the drug response and the assessment of several drugs at once. However, in terms of drug policy change its results might be difficult to interpret although they may be used as an early warning system for 2nd or 3rd line drugs. The new WHO 14-days in vivo test addresses mainly the problem of treatment failure and of haematological parameters changes in sick children. It gives valuable information on whether a drug still `works'. None of these methods are well suited for large-scale studies. Molecular methods based on detection of mutations in parasite molecules targeted by antimalarial drugs could be attractive tools for surveillance. However, their relationship with in vivo test results needs to be established

The use of bacterial larvicides in mosquito and black fly control programmes in Brazil

Bacillus spp. based larvides are increasingly replacing, with numerous advantages, chemical insecticides in programmes for controlling black fly and mosquito populations. Brazil was among the pioneers in adopting Bacillus thuringiensis israelensis (B.t.i) to control black flies. However, the major current mosquito control programme in Brazil, the Programme for Eradication of Aedes aegypti launched in 1997, only recently decided to replace temephos by B.t.i based larvicides, in the State of Rio de Janeiro. In the last decade, works developed by research groups in Brazilian institutions have generated a significant contribution to this subject through the isolation of B. sphaericus new strains, the development of new products and the implementation of field trials of Bacillus efficacy against mosquito species under different environmental conditions.

Quimiometria I: calibração multivariada, um tutorial

The aim of this work is to present a tutorial on Multivariate Calibration, a tool which is nowadays necessary in basically most laboratories but very often misused. The basic concepts of preprocessing, principal component analysis (PCA), principal component regression (PCR) and partial least squares (PLS) are given. The two basic steps on any calibration procedure: model building and validation are fully discussed. The concepts of cross validation (to determine the number of factors to be used in the model), leverage and studentized residuals (to detect outliers) for the validation step are given. The whole calibration procedure is illustrated using spectra recorded for ternary mixtures of 2,4,6 trinitrophenolate, 2,4 dinitrophenolate and 2,5 dinitrophenolate followed by the concentration prediction of these three chemical species during a diffusion experiment through a hydrophobic liquid membrane. MATLAB software is used for numerical calculations. Most of the commands for the analysis are provided in order to allow a non-specialist to follow step by step the analysis.

O modelamento estatístico de misturas: experimento tutorial usando voltametria de redissolução anódica

This work illustrates the modeling procedure for a solvent mixture using the simplex- centroid approach. The selected experiment was the optimization of the peak current observed in the direct determination of nickel by anodic stripping voltammetry (ASV) in a solvent mixture composed of N,N-dimethylformamide, ethanol and water. The text is presented in a tutorial way, showing in detail the several steps which must be followed in such a process. Since not all possible mixtures lead to a measurable instrumental response, pseudocomponents had to be used to rescale the experimental design. This also allows to show how to apply this tool, usually troublesome for non-specialists in mixture modeling procedures.

Quimiometria II: planilhas eletrônicas para cálculos de planejamentos experimentais, um tutorial

This work describes, through examples, a simple way to carry out experimental design calculations applying an spreadsheets. The aim of this tutorial is to introduce an alternative to sophisticated commercial programs that normally are too complex in data input and output. An overview of the principal methods is also briefly presented. The spreadsheets are suitable to handle different types of computations such as screening procedures applying factorial design and the optimization procedure based on response surface methodology. Furthermore, the spreadsheets are sufficiently versatile to be adapted to specific experimental designs.

Experimento didático de quimiometria para análise exploratória de óleos vegetais comestíveis por espectroscopia no infravermelho médio e análise de componentes principais: um tutorial, parte I

This manuscript aims to show the basic concepts and practical application of Principal Component Analysis (PCA) as a tutorial, using Matlab or Octave computing environment for beginners, undergraduate and graduate students. As a practical example it is shown the exploratory analysis of edible vegetable oils by mid infrared spectroscopy.

Experimento didático de quimiometria para calibração multivariada na determinação de paracetamol em comprimidos comerciais utilizando espectroscopia no infravermelho próximo: um tutorial, parte II

The aim of this manuscript was to show the basic concepts and practical application of Partial Least Squares (PLS) as a tutorial, using the Matlab computing environment for beginners, undergraduate and graduate students. As a practical example, the determination of the drug paracetamol in commercial tablets using Near-Infrared (NIR) spectroscopy and Partial Least Squares (PLS) regression was shown, an experiment that has been successfully carried out at the Chemical Institute of Campinas State University for chemistry undergraduate course students to introduce the basic concepts of multivariate calibration in a practical way.

Experimento didático de quimiometria para planejamento de experimentos: avaliação das condições experimentais na determinação espectrofotométrica de ferro II com o-fenantrolina. Um tutorial, parte III

The objective of this manuscript is to describe a practical experiment that can be employed for teaching concepts related to design of experiments using Matlab or Octave computing environment to beginners, undergraduate and graduate students. The classical experiment for determination of Fe (II) using o-phenanthroline was selected because it is easy to understand, and all the required materials are readily available in most analytical laboratories. The approach used in this tutorial is divided in two steps: first, the students are introduced to the concept of multivariate effects, how to calculate and interpret them, and the construction and evaluation of a linear model to describe the experimental domain by using a 2³ factorial design. Second, an extension of the factorial design by adding axial points is described, thereby, providing a central composite design. The quadratic model is then introduced and used to build the response surface.

Avaliação formativa em sessão tutorial: concepções e dificuldades

A proposta deste trabalho é apreender concepções de estudantes e tutores sobre a avaliação formativa nas sessões tutoriais de um currículo PBL, identificando as dificuldades enfrentadas no desenvolvimento dessa prática. Um questionário Likert foi aplicado a 11 tutores e 45 discentes do sétimo período do curso de Medicina da Universidade Estadual de Montes Claros e uma entrevista de aprofundamento foi realizada com a totalidade dos tutores e 20 estudantes. Os entrevistados percebem a proposta formativa da avaliação na sessão tutorial, definindo-a como processual, reflexiva, dialógica, diagnóstica, e enfatizam a possibilidade de feedback como fator motivador e determinante para solucionar as deficiências detectadas e reforçar as potencialidades percebidas. São identificadas dificuldades relacionadas ao desempenho dos docentes, como falta de preparo, ao desempenho dos estudantes (falta de sinceridade, maturidade) e outras decorrentes da inadequação dos critérios utilizados nos instrumentos avaliativos. Os resultados apontam a necessidade de programas de desenvolvimento docente e discente em avaliação, assim como maior compromisso das instituições que utilizam a metodologia Aprendizagem Baseada em Problemas na busca contínua e reflexiva da coerência com os pressupostos pedagógicos estabelecidos pelo currículo.