A web-based tool to aid the identification of chemicals potentially posing a health risk through percutaneous exposure

Occupational hygiene practitioners typically assess the risk posed by occupational exposure by comparing exposure measurements to regulatory occupational exposure limits (OELs). In most jurisdictions, OELs are only available for exposure by the inhalation pathway. Skin notations are used to indicate substances for which dermal exposure may lead to health effects. However, these notations are either present or absent and provide no indication of acceptable levels of exposure. Furthermore, the methodology and framework for assigning skin notation differ widely across jurisdictions resulting in inconsistencies in the substances that carry notations. The UPERCUT tool was developed in response to these limitations. It helps occupational health stakeholders to assess the hazard associated with dermal exposure to chemicals. UPERCUT integrates dermal quantitative structure-activity relationships (QSARs) and toxicological data to provide users with a skin hazard index called the dermal hazard ratio (DHR) for the substance and scenario of interest. The DHR is the ratio between the estimated 'received' dose and the 'acceptable' dose. The 'received' dose is estimated using physico-chemical data and information on the exposure scenario provided by the user (body parts exposure and exposure duration), and the 'acceptable' dose is estimated using inhalation OELs and toxicological data. The uncertainty surrounding the DHR is estimated with Monte Carlo simulation. Additional information on the selected substances includes intrinsic skin permeation potential of the substance and the existence of skin notations. UPERCUT is the only available tool that estimates the absorbed dose and compares this to an acceptable dose. In the absence of dermal OELs it provides a systematic and simple approach for screening dermal exposure scenarios for 1686 substances.

Impact of the Femoral Head Position on Moment Arms in Total Hip Arthroplasty: A Parametric Finite Element Study.

BACKGROUND: Although the importance of accurate femoral reconstruction to achieve a good functional outcome is well documented, quantitative data on the effects of a displacement of the femoral center of rotation on moment arms are scarce. The purpose of this study was to calculate moment arms after nonanatomical femoral reconstruction. METHODS: Finite element models of 15 patients including the pelvis, the femur, and the gluteal muscles were developed. Moment arms were calculated within the native anatomy and compared to distinct displacement of the femoral center of rotation (leg lengthening of 10 mm, loss of femoral offset of 20%, anteversion ±10°, and fixed anteversion at 15°). Calculations were performed within the range of motion observed during a normal gait cycle. RESULTS: Although with all evaluated displacements of the femoral center of rotation, the abductor moment arm remained positive, some fibers initially contributing to extension became antagonists (flexors) and vice versa. A loss of 20% of femoral offset led to an average decrease of 15% of abductor moment. Femoral lengthening and changes in femoral anteversion (±10°, fixed at 15°) led to minimal changes in abductor moment arms (maximum change of 5%). Native femoral anteversion correlated with the changes in moment arms induced by the 5 variations of reconstruction. CONCLUSION: Accurate reconstruction of offset is important to maintaining abductor moment arms, while changes of femoral rotation had minimal effects. Patients with larger native femoral anteversion appear to be more susceptible to femoral head displacements.

Preparation of a blood culture pellet for rapid bacterial identification and antibiotic susceptibility testing.

Bloodstream infections and sepsis are a major cause of morbidity and mortality. The successful outcome of patients suffering from bacteremia depends on a rapid identification of the infectious agent to guide optimal antibiotic treatment. The analysis of Gram stains from positive blood culture can be rapidly conducted and already significantly impact the antibiotic regimen. However, the accurate identification of the infectious agent is still required to establish the optimal targeted treatment. We present here a simple and fast bacterial pellet preparation from a positive blood culture that can be used as a sample for several essential downstream applications such as identification by MALDI-TOF MS, antibiotic susceptibility testing (AST) by disc diffusion assay or automated AST systems and by automated PCR-based diagnostic testing. The performance of these different identification and AST systems applied directly on the blood culture bacterial pellets is very similar to the performance normally obtained from isolated colonies grown on agar plates. Compared to conventional approaches, the rapid acquisition of a bacterial pellet significantly reduces the time to report both identification and AST. Thus, following blood culture positivity, identification by MALDI-TOF can be reported within less than 1 hr whereas results of AST by automated AST systems or disc diffusion assays within 8 to 18 hr, respectively. Similarly, the results of a rapid PCR-based assay can be communicated to the clinicians less than 2 hr following the report of a bacteremia. Together, these results demonstrate that the rapid preparation of a blood culture bacterial pellet has a significant impact on the identification and AST turnaround time and thus on the successful outcome of patients suffering from bloodstream infections.

Identification des dermatophytes en cultures sur la base de leurs critères macroscopiques et microscopiques

Contexte : Les dermatophytes sont des champignons filamenteux parasites spécialisés qui dégradent les tissus kératinisés. Ils sont responsables de la plupart des mycoses de la peau, du cuir chevelu et des cheveux, et des ongles. Le choix du traitement des dermatophytoses dépend des symptômes et du dermatophyte incriminé parmi une quinzaine d'espèces possibles. L'identification des dermatophytes se fait en général sur la base des caractères macroscopiques et microscopiques des cultures. L'identification est parfois difficile ou reste incertaine car il peut y avoir des variations d'un isolat à l'autre au sein d'une même espèce. Cependant, les espèces sont facilement identifiées sur la base de séquences d'ADN. En pratique, des séquences d'ADN ribosomique suffisamment polymorphes sont le plus souvent utilisées pour discriminer les espèces de dermatophytes. Des méthodes spécialisées et sophistiquées telles que les séquences d'ADN et la spectrométrie de masse sont de plus en plus proposées dans la littérature pour identifier les dermatophytes. Toutefois, ces méthodes ne peuvent pas être utilisées directement par un médecin dans un cabinet médical. C'est pourquoi des méthodes plus simples basées sur l'observation de caractères phénotypiques des champignons en culture ne devraient pas être abandonnées. Objectif : Etablir une clé d'identification dichotomique se basant sur des caractères macroscopiques et microscopiques permettant une identification fiable du dermatophyte par la culture. Des clés d'identification des espèces seront élaborées et testées pour leur validation en parallèle avec leur identification par des méthodes de Biologie Moléculaire. Créer un outil simple qui pourra être utilisé au laboratoire par des médecins ou des biologistes non spécialisés en mycologie pour identifier les dermatophytes sans avoir recours à une technologie sophistiquée. Méthodes : Inventaire des espèces isolées de 2001 à 2012 au laboratoire de dermatologie du CHUV. Inventaire des caractères phénotypiques permettant de caractériser chaque espèce. Création d'un système dichotomique sur la base des caractères phénotypiques pour séparer et identifier les espèces (clé d'identification des espèces). Résultats attendus : Les résultats attendus sont définis au niveau des objectifs. L'outil doit être accessible pour des personnes inexpérimentées qui pourront alors identifier les dermatophytes. Plus-value : Les dermatophytoses sont fréquemment diagnostiquées. Cet outil est destiné à tous les dermatologues installés et au personnel de laboratoire qui ne sont pas nécessairement spécialisés en la matière.