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Third Measurement (third + measurement)
Selected AbstractsGene expression measurements in the context of epidemiological studiesALLERGY, Issue 12 2008C. Bieli Background:, Gene expression measurements became an attractive tool to assess biological responses in epidemiological studies. However, collection of blood samples poses various technical problems. We used gene expression data from two epidemiological studies to evaluate differences between sampling methods, comparability of two methods for measuring RNA levels and stability of RNA samples over time. Methods:, For the PARSIFAL study, PBLC of 1155 children were collected using EDTA tubes in two countries. In the PASTURE study, tubes containing RNA-stabilizing solutions (PAXgene® Blood RNA Tubes; PreAnalytiX) were used to collect cord blood leucocytes of 982 children in five countries. Real-time PCR (conventional single tube assay and high-throughput low density arrays) was used to quantify expression of various innate immunity genes. In 77 PARSIFAL samples, gene expression was measured repeatedly during prolonged storage. Results:, In PARSIFAL (EDTA tubes) the median RNA yield after extraction significantly differed between the two centres (70 and 34 ng/,l). Collecting blood into an RNA-stabilizing solution markedly reduced differences in RNA yield in PASTURE (range of medians 91,107 ng/,l). The agreement [Spearman rank correlation (r)] between repeated measurements of gene expression decreased with increasing storage time [e.g., for CD14: r (first/second measurement) = 0.35; r (first/third measurement) = 0.03]. RNA levels measured with either the conventional method or low-density arrays were comparable (r > 0.9). Conclusion:, Collecting blood samples into tubes containing an RNA-stabilizing solution increases RNA yield and reduces its variability. Long-term storage of samples may lead to RNA degradation, requiring special attention in longitudinal studies. [source] Do smoking attitudes predict behaviour?ADDICTION, Issue 10 2008A longitudinal study on the bi-directional relations between adolescents' smoking attitudes, behaviours ABSTRACT Aims Prevention and intervention programmes focus frequently upon retaining or creating negative attitudes towards smoking in an effort to prevent adolescents from smoking. As the focus upon attitudes is central in these programmes it is essential to know whether smoking attitudes actually precede smoking behaviour or, conversely, are affected by it. Therefore, in the present study we examined to what extent bi-directional relations existed between smoking attitudes and behaviour. Design Data were used from the three annual waves of the ,Family and Health' project. Setting Participants were asked to complete questionnaires individually at their homes. Participants Addresses of families consisting of two parents and two adolescents were obtained from the records of 22 municipalities in the Netherlands. At baseline, 428 families participated with a response rate of 94% at the third measurement. Measurements Self-reports were used to assess adolescents' smoking attitudes and behaviour. Associations between smoking attitudes and behaviour were tested using structural equation modelling. Findings Findings revealed that smoking attitudes did not predict smoking consistently over time. However, past smoking affected subsequent attitudes moderately, suggesting that adolescents who started to smoke developed less negative attitudes towards smoking. Conclusions The current findings imply that smoking behaviour predominantly shapes smoking-related attitudes, rather than vice versa. Focusing merely on smoking attitudes is probably not enough to prevent adolescents from smoking. [source] The effect of a major event on stereotyping: terrorist attacks in Israel and Israeli adolescents' perceptions of Palestinians, Jordanians and ArabsEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 3 2001Daniel Bar-Tal This study examines the effect of a major event (terrorist attacks) on the stereotypic perceptions, attitudes and affects of 119 Israeli adolescents (56 males and 63 females of 5th and 8th grades) toward three target groups: (a) Palestinians, who still have conflictive relations with the Israelis (Palestinian extremists carried out the attacks), (b) Jordanians, who have peaceful relations with the Israelis and (c) Arabs, in general, who are considered a subcategory including Arabs of all nations. The questionnaires were administered to the same adolescents three times: during a relatively peaceful spell in Israeli,Palestinian relations; one day following two terrorist attacks, and three months thereafter. In the last administration adolescents' need for closure was also measured. Adolescents' perceptions, attitudes and affect toward the three target group were differentiated,relating to Palestinians most negatively and to Jordanians most positively. Also, following the terrorist attacks, stereotypic perceptions and attitudes changed in a negative direction, in relation to all the three groups; again with expressed differentiation among the three groups. In the third measurement, some measures remained negative, but some changed to be more positive. Only few effects of age were detected and several significant correlation with need for closure were found. These results indicate that stereotypes and attitudes toward outgroups are context-dependent, influenced by events; thus they serve as ,a seismograph' to the quality of intergroup relations at any given time. Copyright © 2001 John Wiley & Sons, Ltd. [source] How should we estimate driving pressure to measure interrupter resistance in children?PEDIATRIC PULMONOLOGY, Issue 9 2007MB ChB, P. Seddon BSc Abstract Interrupter resistance (Rint) is a widely used measure of airway caliber, but concerns remain about repeatability and sensitivity. Some Rint variability may derive from the linear back-extrapolation algorithm (LBE 30/70) usually used to estimate driving pressure. To investigate whether other methods of estimating driving pressure could improve repeatability and sensitivity, we studied 39 children with asthma. Two measurements of Rint,each the median of 10 interruptions,were made 5 min apart, and 14 children had a third measurement after bronchodilator (RintBD). Mouth pressure transients were analyzed using several algorithms, to compare the magnitude, repeatability, and sensitivity to bronchodilator change of Rint values yielded. Algorithms taking driving pressure from later in the transient, predictably, yielded higher values of Rint than those which back-extrapolated to time of valve closure. Algorithms which did not rely on back-extrapolation, including mean oscillation pressure (MOP) and mean plateau pressure (MP 30/70) had better repeatability. Sensitivity to detect change, calculated as ratio of bronchodilator response to repeatability coefficient (,Rint/CR), was also better for non-extrapolating algorithms: MP 30/70 1.67, LBE 30/70 1.28 (P,=,0.0004). Measuring Rint using techniques other than conventional back-extrapolation may give more consistent and clinically useful results, and these approaches merit further exploration. Pediatr Pulmonol. 2007; 42:757,763. © 2007 Wiley-Liss, Inc. [source] | ||||||||||