Contribution of toxicological analysis to the care of dimethyl fumarate dermatitis

Background: Dimethyl fumarate (DMFu) is a fungicide which is used in Chinese manufactures of furniture and shoes to avoid mould spoiling of fabrics. In 2008, DMFu was found the responsible allergen for several cases of contact dermatitis from armchairs and shoes observed in Europe. In France a national toxicovigilance survey was set up and importation of products containing dimethyl fumarate is now forbidden. Case report: a 36 year-old woman, with no history of previous allergy, was hospitalized because of a severe acute eczema of her feet after wearing a new pair of boots inside which she had noticed desiccant sachets. She strongly reacted on patch testing to DMFu and to the content of a sachet which was identified as DMFu, both at 0.01%, 0.1%, 1% in petrolatum, and also to a piece of the fabric of her boots, patch tested as is. Materials and method: Boot fabrics and mould-proof sachets found in the boots were analysed by HPLC/UV/DAD and GC/MS after methanol extraction. Further samples of anti mould agent sachets or shoe fabrics from 5 other patients with suspicion of DMFu dermatitis were analysed with the same procedure. Some of them were transferred to the laboratory several months after healing of the dermatitis. Results: DMFu was found in all the samples from 1 to 100% in sachets or from 20 to 2000 μg/g in the fabrics of shoes, even after one year. These findings contributed to ensure the responsibility of DMFu in the dermatitis of the patients and demonstrate that DMFu may remain a long time in the contaminated fabrics after removal of the sachets. This study also points out the usefulness of the collaboration between dermatologists, biologists and poison centre practitioners

Rapid Sampling of Molecules via Skin for Diagnostic and Forensic Applications

Skin provides an excellent portal for diagnostic monitoring of a variety of entities; however, there is a dearth of reliable methods for patient-friendly sampling of skin constituents. This study describes the use of low-frequency ultrasound as a one-step methodology for rapid sampling of molecules from the skin. Sampling was performed using a brief exposure of 20 kHz ultrasound to skin in the presence of a sampling fluid. In vitro sampling from porcine skin was performed to assess the effectiveness of the method and its ability to sample drugs and endogenous epidermal biomolecules from the skin. Dermal presence of an antifungal drug—fluconazole and an abused substance, cocaine—was assessed in rats. Ultrasonic sampling captured the native profile of various naturally occurring moisturizing factors in skin. A high sampling efficiency (79 ± 13%) of topically delivered drug was achieved. Ultrasound consistently sampled greater amounts of drug from the skin compared to tape stripping. Ultrasonic sampling also detected sustained presence of cocaine in rat skin for up to 7 days as compared to its rapid disappearance from the urine. Ultrasonic sampling provides significant advantages including enhanced sampling from deeper layers of skin and high temporal sampling sensitivity

Non-invasive positive-pressure ventilation in children in otolaryngology

SummaryIntroductionObstructive diseases of the upper airways are common in children and sometimes difficult to manage. Non-invasive positive-pressure ventilation (NPPV) consists of delivering continuous positive pressure during all or part of the respiratory cycle via a non-invasive interface (face mask or nasal mask, or nasal prongs). NPPV is the treatment of choice for severe obstructive sleep apnoea in children and should be considered prior to tracheotomy and is also indicated in the case of persistent sleep-disordered breathing following surgical treatment, a frequent situation in children with a malformation of the head and neck or upper airways.DiscussionA simple ventilator, able to deliver continuous positive airway pressure, is sufficient is most cases in otolaryngology. The interface represents the major technical limitation of NPPV, especially in infants for whom no appropriate commercial interface is available. A sleep study before and after initiation of NPPV, followed by regular follow-up examinations, is essential to confirm correction of gas exchanges and sleep quality in response to NPPV.ConclusionFinally, NPPV must be performed in a specialized paediatric centre with specific expertise in this field

Reverse iontophoresis of lithium: electrode formulation using a thermoreversible polymer

This work investigated the use of a thermoreversible get as a collector vehicle in reverse iontophoresis applications. A 20% (w/w) aqueous gel of Pluronic F127 was a suitable receptor medium to be used at the cathodal chamber. In vitro iontophoresis experiments investigated the simultaneous extraction of lithium (analyte of interest) and sodium (used as an internal standard) into either a control buffer or a gelled receptor. The gelification process at room temperature provided a suitable consistency and contact with the skin surface during the iontophoresis experiments. Subsequent cooling of the gelled solution to 4 degreesC allows an easy recovery of lithium and sodium for later quantification. Both the lithium extraction fluxes and the lithium to sodium ratio of extraction fluxes were linearly related to the subdermal lithium concentration. On the whole, the results show that thermoreversible polyiner solutions offer a simple and convenient way to handle samples in reverse iontophoresis Studies. (C) 2004 Elsevier B.V. All rights reserved

Spatial heterogeneity of periphytic microbial communities in a small pesticide-polluted river

Spatial variability in the microbial community composition of river biofilms was investigated in a small river using two spatial scales: one monitored the upstream-downstream pesticide contamination gradient, referred to as the 'between-section variability', and the other monitored a 100-m longitudinal transect (eight sampling sites per section) within each sampling section, referred to as the 'within-section variability'. Periphyton samples were collected in spring and winter on artificial substrates placed in the main channel of the river. Denaturing gradient gel electrophoresis (DGGE) was used to assess the prokaryotic and eukaryotic community richness and diversity, and HPLC pigment analysis to assess the global taxonomic composition of the photoautotrophic community. In order to try to reduce the biological variability due to differences in flow velocity and in light conditions within each sampling section, and consequently to take into account only the changes due to water chemistry, nine plates (three per sampling section) subjected to similar physical conditions were chosen, and the results for these plates were compared with those obtained for all 24 plates. As shown by DGGE and by HPLC analyses, using these three substrate plates exposed to similar environmental conditions did indeed reduce the within-section variability and maximize the between-section variability. This sampling strategy also improved the evaluation of the impact of pollutants on the periphytic communities, measured using short-term sensitivity testing