Abstract-Vitellogenin, a yolk-precursor protein normally found only in the blood plasma of sexually mature female teleosts and other egg-laying vertebrates, was used as an indicator of exposure of male rainbow trout (Oncorhynchus mykiss) to exogenous estrogens. Vitellogenin concentrations were measured using a specific radioimmunoassay for trout. Cages containing adult male trout were placed at the points of discharge and at varying distances downstream of treated sewage effluent outfalls into the River Lea (UK) during the summer and winter months of 1992. After 3 weeks exposure at the majority of sites, fish held up to 15 km downstream of inputs showed an increase in plasma vitellogenin concentration, with statistically significant elevations up to 4.5 km downstream. A repeat survey in November 1992 below Harpenden sewage treatment works showed that the only two stations to give a significant response were 3 m and 1.6 km downstream of the outfall. This reduced effect compared to the first survey is thought to be due to dilution of both the influent sewage to the treatment works and of the river water itself by increased rainfall, the overall increase in dilution being approx. 36%. Trout were also placed in 15 raw water storage reservoirs in southeast England during the summer of 1993 for an exposure period of 6 weeks. No biologically significant increases in plasma vitellogenin concentration were observed in any of the reservoirs.

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These results show a low yield of positive photopatch tests. Thus, despite the large increase in the use of UV filters over the last decade, the development of PA reactions remains rare. Furthermore, most of the common UV filter photoallergens identified in this study, including PABA, amyl dimethyl PABA and benzophenone-10, are now rarely used in sunscreen manufacture, while isopropyl dibenzoylmethane was voluntarily removed from the market in 1993. Currently, benzophenone-3 is the commonest contact photoallergen still in widespread use. In contrast, the UVB filter octyl methoxycinnamate, used in a number of sunscreens, produced only two positive PA reactions in 12 years of testing. Nevertheless, although these reactions are extremely rare, patients with photodermatoses such as PLE and chronic actinic dermatitis do represent a group of patients at increased risk of developing photoallergy. Further photopatch test series should be regularly reviewed and updated, as the relevance of individual photoallergens changes over time. Currently, there is no evidence that PA reactions represent a common clinical problem.

The effective toxicological evaluation of skin sensitization demands that potential contact allergens are identified and that the likely risks of sensitization among exposed populations assessed. By definition, chemicals which possess the toxicological property of skin sensitization potentially are capable of causing allergic contact dermatitis (ACD) in humans. However, this hazard is not an all-or-none phenomenon; clear dose-response relationships can be discerned and thresholds identified for both the induction of sensitization and the elicitation of contact dermatitis. Commonly, these parameters are grouped under the heading of potency, determination of which is vital for risk assessment. In the present investigation, the local lymph node assay (LLNA) has been employed to determine the relative potency of a range of 20 chemicals. The parameter used is the estimated concentration required to produce a 3-fold increase in draining lymph-node cell proliferative activity, the EC3 value. These measurements have been compared with an assessment of the human sensitizing potency of the 20 selected chemicals, each being assigned to 1 of 5 classes based on their human sensitizing potency. The EC3 value, derived from LLNA work carried out in acetone/ olive oil vehicle, correlated well with the human classification, with the strongest sensitizers having low EC3 values (

Fragrances are widely encountered in our daily environment and are known to be a common cause of allergic contact dermatitis. We have reviewed our patch test data from 1980 to 1996 to establish whether the pattern of fragrance allergy has changed with time. During this period, 25,545 patients (10,450 male, 15,005 female) were patch tested with the European standard series. The mean annual frequency of positive reactions to the fragrance mix was 8.5% in females (range 6.1-10.9) and 6.7% in males (range 5.1-12.9). Females were 1.3 times more likely to be allergic to fragrance (P < 0.001, 95% confidence interval, CI 1.17-1.41). Males with fragrance allergy were older than females by 5.6 years (mean age 48.2 vs. 42.6 years; P < 0.001, 95% CI 3.9-7.3). The incidence of a concomitant positive patch test to balsam of Peru in fragrance-sensitive patients showed wide variation, suggesting that it is not a reliable marker of fragrance allergy. There was a positive correlation between the isomers isoeugenol and eugenol. Oak moss remained the most common overall allergen throughout the study, positive in 38.3% of females and 35.6% of males who were tested to the constituents of the fragrance mix. During the period of the study the incidence of positive tests to oak moss increased by 5% yearly (P = 0.001, 95% CI 2.2-8.7). The frequency of allergic reactions to eugenol and geraniol remained relatively constant. Isoeugenol and alpha-amyl cinnamic aldehyde sensitivity increased and hydroxycitronellal showed a slow decline. There was a striking reduction in the frequency of sensitivity to cinnamic aldehyde (by 18% yearly; P < 0.001, 95% CI 14.3-21.0) and cinnamic alcohol (by 9% yearly; P < 0.001, 95% CI 5.2-12.9); these are now uncommon fragrance allergens. These data show temporal trends which may reflect the frequency of population exposure to individual fragrances.