Photopatch testing: a consensus methodology for Europe

A group of interested European Contact Dermatologists/Photobiologists met to produce a consensus statement on methodology, test materials and interpretation of photopatch testing. While it is recognized that a range of local variables operate throughout Europe, the underlying purpose of the work is to act as an essential preamble to a Pan European Photopatch Test Study focusing particularly on sunscreen chemicals.     

儿童红细胞生成性原卟啉病多器官功能衰竭一例并文献复习

红细胞生成性原卟啉病是一种罕见病,其病因是患者体内基因突变（FECH基因）引起的亚铁螯合酶活性受损。本文通过回顾1例红细胞生成性原卟啉病患儿的临床资料以及相关基因的检测结果,并进行文献复习,探讨红细胞生成性原卟啉病的临床特点及致病基因的突变位点,以提高临床医生对该病的认识。对临床上反复曝光部位的皮疹,尤其伴有腹痛、肝损害时,应警惕红细胞生成性原卟啉病,FECH基因检测有助于该病的诊断。     

Psoralen photoallergy caused by plant contact

A case of acquired photocontact allergy to furocumarins in plants is reported. Photopatch testing was performed with four psoralens [8-melhoxypsoralen (8-MOP), 5-methoxypsoralens (5-MOP), trimethylpsoralen (TMP) and imperatorin (IMP)]. The use of serial dilutions of the test compounds made it possible to differentiate between photoallergic and phototoxic reactions. 8-MOP gave a positive eczematous text reaction down to a concentration of 0.0001% The reactions to 5-MOP and IMP also were positive, while that to TMP was negative. Histopathological examination of a biopsy specimen from a positive test site showed changes consistent with photoallergic contact dermatitis.
The multiple reactions could be explained on the basis of multiple sensitization, but cross reactions cannot be ruled out.     

High throughput screening (HTS) for phototoxicity hazard using the in vitro 3T3 neutral red uptake assay

Testing for phototoxic hazard is usually carried out for product ingredients intended for use on skin, which may be exposed to sunlight. Unilever currently uses the validated in vitro 3T3 Neutral Red Uptake phototoxicity test (NRU PT). This protocol involves 2–3 experiments, each taking 3 days to perform. One person can test up to seven test materials plus positive control at any one time, requiring 0.5 g test material. Higher throughput is required where libraries of potential actives are being generated and screening for potential phototoxicants is required. A proposed HTS protocol would use the NRU PT, but only one concentration (10 μg/ml) in a single experiment. The validity of the HTS protocol was investigated by a retrospective examination of data from 86 materials previously tested. Phototoxic hazard predictions made using the conventional NRU PT were compared with those obtained if only data at 10 μg/ml were considered. A majority of 73 materials (84.9%) gave agreement in predictions between the two protocols; for 13 materials (15.1%) the assessments did not agree. There were no false positives; however, there were some false negatives, i.e., predicted as phototoxic from the conventional assay, but non-phototoxic at 10 μg/ml. As this protocol is intended for screening purposes only it is considered that this would be acceptable at this stage in material selection. One person could screen 128 test materials in 3 days, requiring <1 mg test material, giving a substantial increase in productivity. Any material selected for further development and inclusion in a formulation may require further confirmatory testing, e.g. using a human skin model assay for phototoxicity.     

卫生纸中荧光增白剂的光毒、光敏和致突变性研究

目的　研究荧光增白剂的光毒、光敏和致突变性。方法　按照ＧＢ７９１９ － ８７ 中的光毒、光敏和Ａｍｅｓ试验方法。结果　荧光增白剂的光毒、光敏和Ａｍｅｓ 试验结果为阴性。结论　本研究中的卫生纸荧光增白剂不具有光毒性和致突变性，也非光敏物质。