A standardized framework for the validation and verification of clinical molecular genetic tests

The validation and verification of laboratory methods and procedures before their use in clinical testing is essential for providing a safe and useful service to clinicians and patients. This paper outlines the principles of validation and verification in the context of clinical human molecular genetic testing. We describe implementation processes, types of tests and their key validation components, and suggest some relevant statistical approaches that can be used by individual laboratories to ensure that tests are conducted to defined standards.     

Near-Infrared (NIR) Monitoring of H2O2 Vapor Concentration During Vapor Hydrogen Peroxide (VHP) Sterilisation

Purpose. There is an increasing use in the pharmaceutical industry of barrier systems such as transfer isolators, sterilisation tunnels and work station isolators. As Vapor Hydrogen Peroxide (VHP) sterilisation of isolators and lyophilizers becomes an important sterilisation method, there is an acute need for a VHP monitoring system to be used for in-process control and validation. In this study, near infrared (NIR) spectrofotometry was evaluated as a potential technique to monitor hydrogen peroxide. Additionally the H₂O₂ vapor permeability of different packaging materials, commonly used in steam and ethylene oxide sterilisation, was evaluated. Methods. NIR spectrofotometry, using a gas cell connected with optic fibres, was evaluated as a potential technique to monitor hydrogen peroxide vapor and water vapor during VHP sterilisation of an isolator. A NIR spectrum was taken every 30 s during VHP sterilisation of an isolator. The influence of injection rate, air flow rate, working temperature and gas distribution was investigated. The H₂O₂ vapor permeability of different packaging materials was determined by placing the gas cell in the sterilisation bags and sealing the bags hermetically. The sterilisation bag was then subjected to VHP sterilisation. Results. The NIR spectra taken at steady state sterilization conditions showed 4 absorption peaks: at 1364,1378 and 1400 nm attributed to water and at 1420 nm attributed to H₂O₂ vapor. By measuring the absorbance level at these wavelengths, the actual concentration of H₂O and H₂O₂ vapor in the isolator was calculated. The water vapor permeation of the sterilisation bags, measured with NIR, appeared to be equal for all materials tested. Whereas Tyvek^® was the most permeable material for hydrogen peroxide vapor (82.7% of the reference concentration outside the bag), only 30% was found in bags made of medical paper. Sterilisation bags consisting of laminate films and PVC sealed to medical paper showed intermediate permeability. Conclusions. Near-infrared (NIR) spectroscopy using a gascell with optic fibres is a useful technique to monitor VHP sterilisation cycles. There was a difference in H₂O₂ vapor permeability of different packaging materials, commonly used in steam and ethylene oxide sterilisation.     

Depression research and treatment: are we skating to where the puck is going to be?

This paper critically reviews empirical findings regarding current key assumptions underlying the nature and treatment of depression which heavily rely on the DSM approach. This review shows that empirical evidence provides little support for these assumptions. In response to these findings, an etiologically based, biopsychosocial, dynamic interactionism model of depression is proposed. This model could foster further integration in research on depression and assist in the development of guidelines for the treatment of depression that are better informed by research findings and more congruent with complex clinical realities.     

Dependency and self-criticism: relationship with major depressive disorder, severity of depression, and clinical presentation

Dependency and self-criticism have been proposed as personality dimensions that confer vulnerability to depression. In this study we set out to investigate the diagnostic specificity of these personality dimensions and their relationship with gender differences, severity of depression, and specific depressive symptoms. Levels of dependency and self-criticism as measured by the Depressive Experiences Questionnaire (DEQ) were compared among patients with major depressive disorder (MDD; n=93), mixed psychiatric patients (n=43), university students (n=501), and community adults (n=253). Associations with severity of depression and specific depressive symptoms were also explored. Results showed that dependency was more specifically associated with MDD, whereas self-criticism did not differ between depressed and mixed psychiatric patients. In line with the gender incongruence hypothesis, women with MDD and other psychiatric disorders had higher levels of self-criticism compared to men, whereas men with MDD had higher levels of dependency compared to women. Severity of depression was more clearly linked to self-criticism than to dependency, particularly in patients with MDD. Finally, both dependency and self-criticism were related to theoretically predicted clusters of depressive symptoms, especially after we controlled for shared variance between self-critical and dependent symptoms, respectively. Limitations of this study include the cross-sectional design, which limited the ability to draw causal conclusions. In addition, this study relied exclusively on self-reported personality and mood. Overall, findings of this study suggest that both dependency and self-criticism are associated with MDD, severity of depression, and specific depressive symptoms, and that gender-incongruent personality traits may be associated with increased risk for depression and other disorders.     

Factor structure of the Impact of Event Scale‐Revised in two different Peruvian samples

Background: This article studied the factor structure of the Impact of Event Scale‐Revised (IES‐R) in two samples in Peru, i.e., a sample of survivors of a fire (N=174) and a university student sample (N=562). Methods: First, confirmatory factor analysis was used to compare nine different models of posttraumatic stress disorder symptoms as evaluated by the IES‐R in both of the samples separately. The model with the best fit in both samples had four correlated factors, i.e., Intrusion, Avoidance, Hyperarousal and Sleep Disturbance. Second, the degree of factorial invariance of the IES‐R was compared in both the samples using multiple group confirmatory factor analysis. Results and Conclusions: The results showed almost no differences between both samples. Finally, the results supported the internal consistency, as well as the concurrent and convergent validity of the IES‐R in Peru. Depression and Anxiety, 2009. © 2009 Wiley‐Liss, Inc.