Translation, Cross-Cultural Adaptation, and Validation of Measurement Instruments: A Practical Guideline for Novice Researchers.

Cross-cultural validation of self-reported measurement instruments for research is a long and complex process, which involves specific risks of bias that could affect the research process and results. Furthermore, it requires researchers to have a wide range of technical knowledge about the translation, adaptation and pre-test aspects, their purposes and options, about the different psychometric properties, and the required evidence for their assessment and knowledge about the quantitative data processing and analysis using statistical software. This article aimed: 1) identify all guidelines and recommendations for translation, cross-cultural adaptation, and validation within the healthcare sciences; 2) describe the methodological approaches established in these guidelines for conducting translation, adaptation, and cross-cultural validation; and 3) provide a practical guideline featuring various methodological options for novice researchers involved in translating, adapting, and validating measurement instruments. Forty-two guidelines on translation, adaptation, or cross-cultural validation of measurement instruments were obtained from "CINAHL with Full Text" (via EBSCO) and "MEDLINE with Full Text". A content analysis was conducted to identify the similarities and differences in the methodological approaches recommended. Bases on these similarities and differences, we proposed an eight-step guideline that includes: a) forward translation; 2) synthesis of translations; 3) back translation; 4) harmonization; 5) pre-testing; 6) field testing; 7) psychometric validation, and 8) analysis of psychometric properties. It is a practical guideline because it provides extensive and comprehensive information on the methodological approaches available to researchers. This is the first methodological literature review carried out in the healthcare sciences regarding the methodological approaches recommended by existing guidelines.

Inter-individual variability in esterases in human liver.

Human liver has numerous hydrolytic enzymes involved in metabolism of endogenous and exogenous esters. Of these enzymes, carboxylesterases (EC 3.1.1.1) form an important group which hydrolyses many diverse ester substrates, including pro-ester drugs. Carboxylesterase activity was investigated in liver subcellular fractions from 22 individuals using the general carboxylesterase substrate phenylvalerate and the homologous series of esters methyl-, ethyl-, propyl-, butyl- and benzylparaben. The intra- and inter-individual variation in phenylvalerate and paraben metabolism was compared. Rates of hydrolysis were higher in microsomal fractions than cytosolic fractions for all compounds. The rate of paraben hydrolysis varied depending on the size of the paraben alcohol leaving group, showing a decrease with increasing leaving group size. Comparisons showed that individuals with high rates of hydrolysis towards methyl paraben also showed high rates of hydrolysis to the other parabens and phenylvalerate. Phenylvalerate as a non-specific carboxylesterase substrate was hydrolysed mainly by hCE1 in human livers and there was good correlation with small alcohol leaving group parabens, suggesting hCE1 involvement. Lower correlations with larger alcohol leaving group parabens are consistent with more hCE2 involvement.