Speciation of major arsenic species in seawater by flow injection hydride generation atomic absorption spectrometry.

Arsenic present at 1 microg L(-1) concentrations in seawater can exist as the following species: As(III), As(V), monomethylarsenic, dimethylarsenic and unknown organic compounds. The potential of the continuous flow injection hydride generation technique coupled to atomic absorption spectrometry (AAS) was investigated for the speciation of these major arsenic species in seawater. Two different techniques were used. After hydride generation and collection in a graphite tube coated with iridium, arsenic was determined by AAS. By selecting different experimental hydride generation conditions, it was possible to determine As(III), total arsenic, hydride reactive arsenic and by difference non-hydride reactive arsenic. On the other hand, by cryogenically trapping hydride reactive species on a chromatographic phase, followed by their sequential release and AAS in a heated quartz cell, inorganic As, MMA and DMA could be determined. By combining these two techniques, an experimental protocol for the speciation of As(III), As(V), MMA, DMA and nonhydride reactive arsenic species in seawater was proposed. The method was applied to seawater sampled at a Mediterranean site and at an Atlantic coastal site. Evidence for the biotransformation of arsenic in seawater was clearly shown.

Contact allergy to aeroallergens in children with atopic dermatitis: comparison with allergic contact dermatitis.

Immediate and delayed cutaneous hypersensitivity are believed to be implicated in the physiopathology atopic dermatitis (AD). The purpose of this study was to evaluate Type I and Type IV allergy to aeroallergens in children with AD. 59 children (mean age 5.2 years), presenting with AD according to Hanifin and Rajka's criteria, were skin tested (patch and corresponding prick tests) with common environmental aeroallergens and a restricted panel of the European standard series over a 1-year period. History and clinical data were carefully recorded using a standardized evaluation sheet; total and specific IgE serum levels were evaluated. 17 of 59 patients (28.8%) had at least 1 positive patch test, 32 of 59 patients (54.2%) had at least 1 positive prick test. Corresponding patch and prick tests were observed in 8 out of 17 patients. 5 children with positive patch tests had negative prick tests. Irritant pustular reactions (2/59, i.e. 3%), "angry back" reactions (6/59, i.e. 10%) and doubtful reactions (3/59, i.e. 5%) were excluded from the positive group. Positive patch tests observed included, in decreasing order: D. pteronyssinus and D. farinae (26.8%), garden trees (12.2%), plantain (9.8%), timothy grass, mugwort and damp area trees (4.9% each), and orchard grass (2.44%). 6 children with positive aeroallergen patch tests and 11 children with negative aeroallergen patch tests had at least 1 positive patch test to standard allergens. All children with an irritant reaction to aeroallergens had no reaction to standard patch tests. The relevance of aeroallergens in upgrading the severity of AD lesions has still to be explored by challenge studies and by long-term follow-up.

[Microsporum langeronii dermatophytosis in a newborn infant contaminated in France]. / Dermatophytie à Microsporum langeronii chez un nouveau-né contaminé en France.

Dermatophytosis due to Microsporum langeronii was observed in a 21-day neonate born in Bordeaux, France to a mother of West African origin. A typical misleading manifestations were: non alopecic squamation of the scalp with seborrhoea associated with circineous vesiculo-squamous lesions of the forehead. The source of the contamination was undoubtedly the mother who presented squamation without alopecia of the scalp. M. langeronii were observed in the scales and the hair. Epidemiological search for tinea should be carried out in the family as well as in schools attended by the brothers and sisters. Familial contamination is more frequent.