Re-evaluation of a reported increased micronucleus frequency in lymphocytes of workers occupationally exposed to formaldehyde

A replicate evaluation of increased micronucleus (MN) frequencies in peripheral lymphocytes of workers occupationally exposed to formaldehyde (FA) was undertaken to verify the observed effect and to determine scoring variability. May–Grünwald–Giemsa-stained slides were obtained from a previously performed cytokinesis-block micronucleus test (CBMNT) with 56 workers in anatomy and pathology laboratories and 85 controls. The first evaluation by one scorer (scorer 1) had led to a highly significant difference between workers and controls (3.96 vs 0.81 MN per 1000 cells). The slides were coded before re-evaluation and the code was broken after the complete re-evaluation of the study. A total of 1000 binucleated cells (BNC) were analysed per subject and the frequency of MN (in ‰) was determined. Slides were distributed equally and randomly between two scorers, so that the scorers had no knowledge of the exposure status. Scorer 2 (32 exposed, 36 controls) measured increased MN frequencies in exposed workers (9.88 vs 6.81). Statistical analysis with the two-sample Wilcoxon test indicated that this difference was not significant (p = 0.17). Scorer 3 (20 exposed, 46 controls) obtained a similar result, but slightly higher values for the comparison of exposed and controls (19.0 vs 12.89; p = 0.089). Combining the results of the two scorers (13.38 vs 10.22), a significant difference between exposed and controls (p = 0.028) was obtained when the stratified Wilcoxon test with the scorers as strata was applied. Interestingly, the re-evaluation of the slides led to clearly higher MN frequencies for exposed and controls compared with the first evaluation. Bland–Altman plots indicated that the agreement between the measurements of the different scorers was very poor, as shown by mean differences of 5.9 between scorer 1 and scorer 2 and 13.0 between scorer 1 and scorer 3. Calculation of the intra-class correlation coefficient (ICC) revealed that all scorer comparisons in this study were far from acceptable for the reliability of this assay. Possible implications for the use of the CBMNT in human biomonitoring studies are discussed.

Avaliação da tonopaquimetria como exame de rastreio de glaucoma primário de ângulo aberto

Mestrado em Gestão e Avaliação de Tecnologias em Saúde

Influência da experiência profissional e da função visual do operador no processamento semiautomático da cintigrafia de perfusão do miocárdio: variabilidade intra e interoperador na determinação dos parâmetros quantitativos

Introdução – A cintigrafia de perfusão do miocárdio (CPM) desempenha um importante papel no diagnóstico, avaliação e seguimento de pacientes com doença arterial coronária, sendo o seu processamento realizado maioritariamente de forma semiautomática. Uma vez que o desempenho dos técnicos de medicina nuclear (TMN) pode ser afetado por fatores individuais e ambientais, diferentes profissionais que processem os mesmos dados poderão obter diferentes estimativas dos parâmetros quantitativos (PQ). Objetivo – Avaliar a influência da experiência profissional e da função visual no processamento semiautomático da CPM. Analisar a variabilidade intra e interoperador na determinação dos PQ funcionais e de perfusão. Metodologia – Selecionou-se uma amostra de 20 TMN divididos em dois grupos, de acordo com a sua experiência no software Quantitative Gated SPECTTM: Grupo A (GA) – TMN ≥600h de experiência e Grupo B (GB) – TMN sem experiência. Submeteram-se os TMN a uma avaliação ortóptica e ao processamento de 21 CPM, cinco vezes, não consecutivas. Considerou-se uma visão alterada quando pelo menos um parâmetro da função visual se encontrava anormal. Para avaliar a repetibilidade e a reprodutibilidade recorreu-se à determinação dos coeficientes de variação, %. Na comparação dos PQ entre operadores, e para a análise do desempenho entre o GA e GB, aplicou-se o Teste de Friedman e de Wilcoxon, respetivamente, considerando o processamento das mesmas CPM. Para a comparação de TMN com visão normal e alterada na determinação dos PQ utilizou-se o Teste Mann-Whitney e para avaliar a influência da visão para cada PQ recorreu-se ao coeficiente de associação ETA. Diferenças estatisticamente significativas foram assumidas ao nível de significância de 5%. Resultados e Discussão – Verificou-se uma reduzida variabilidade intra (<6,59%) e inter (<5,07%) operador. O GB demonstrou ser o mais discrepante na determinação dos PQ, sendo a parede septal (PS) o único PQ que apresentou diferenças estatisticamente significativas (zw=-2,051, p=0,040), em detrimento do GA. No que se refere à influência da função visual foram detetadas diferenças estatisticamente significativas apenas na fração de ejeção do ventrículo esquerdo (FEVE) (U=11,5, p=0,012) entre TMN com visão normal e alterada, contribuindo a visão em 33,99% para a sua variação. Denotaram-se mais diferenças nos PQ obtidos em TMN que apresentam uma maior incidência de sintomatologia ocular e uma visão binocular diminuída. A FEVE demonstrou ser o parâmetro mais consistente entre operadores (1,86%). Conclusão – A CPM apresenta-se como uma técnica repetível e reprodutível, independente do operador. Verificou-se influência da experiência profissional e da função visual no processamento semiautomático da CPM, nos PQ PS e FEVE, respetivamente.

Osmolality of preterm formulas suplemented with monprotein energy supplements

Background: Addition of energy supplements to preterm formulas is an optional strategy to increase the energy intake in infants requiring fluid restriction, in conditions like bronchopulmonary dysplasia. This strategy may lead to an undesirable increase in osmolality of feeds, the maximum recommended safe limit being 400 mOsm/kg. The aim of the study was to measure the changes in osmolality of several commercialized preterm formulas after addition of glucose polymers and medium-chain triglycerides. Methods: Osmolality was measured by the freezing point depression method. Six powdered formulas with concentrations of 14 g/100 ml and 16 g/100 ml, and five ready-to-feed liquid formulas were analyzed. All formulas, were supplemented with 10% (low supplementation) or 20% (high supplementation) of additional calories, respectively, in the form of glucose polymers and medium chain triglycerides, maintaining a 1:1 glucose:lipid calorie ratio. Inter-analysis and intra-analysis coefficients of variation of the measurements were always < 3.9%. Results: The mean osmolality (mOsm/kg) of the non-supplemented formulas varied between 268.5 and 315.3 mOsm/kg, increasing by 3–5% in low supplemented formulas, and by 6–10% in high supplemented formulas. None of the formulas analyzed exceeded 352.8 mOsm/kg. Conclusion: The supplementation of preterm formulas with nonprotein energy supplements with up to 20% additional calories did not exceed the maximum recommended osmolality for neonatal feedings.

Development and validation of a psychometric scale for assessing PA chest image quality: a pilot study

Purpose - To develop and validate a psychometric scale for assessing image quality perception for chest X-ray images. Methods - Bandura's theory was used to guide scale development. A review of the literature was undertaken to identify items/factors which could be used to evaluate image quality using a perceptual approach. A draft scale was then created (22 items) and presented to a focus group (student and qualified radiographers). Within the focus group the draft scale was discussed and modified. A series of seven postero-anterior chest images were generated using a phantom with a range of image qualities. Image quality perception was confirmed for the seven images using signal-to-noise ratio (SNR 17.2–36.5). Participants (student and qualified radiographers and radiology trainees) were then invited to independently score each of the seven images using the draft image quality perception scale. Cronbach alpha was used to test interval reliability. Results - Fifty three participants used the scale to grade image quality perception on each of the seven images. Aggregated mean scale score increased with increasing SNR from 42.1 to 87.7 (r = 0.98, P < 0.001). For each of the 22 individual scale items there was clear differentiation of low, mid and high quality images. A Cronbach alpha coefficient of >0.7 was obtained across each of the seven images. Conclusion - This study represents the first development of a chest image quality perception scale based on Bandura's theory. There was excellent correlation between the image quality perception scores derived using the scale and the SNR. Further research will involve a more detailed item and factor analysis.

Incorporação de resíduo da indústria petrolífera em argamassas de cal hidráulica para a reabilitação de edifícios

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Edificações