Hostýnek Jurij J, Dreher Frank, Maibach Howard I
UCSF School of Medicine, Department of Dermatology, San Francisco, CA 94143-0989, USA.
Food Chem Toxicol. 2006 Sep;44(9):1539-43. doi: 10.1016/j.fct.2006.04.003. Epub 2006 Apr 25.
Aim of the study was to shed light on the long-standing controversy whether wearing copper bangles benefits patients suffering from inflammatory conditions such as arthritis. Sequential tape stripping was implemented on healthy volunteers to examine the diffusion of copper through human stratum corneum in vivo following application of the metal as powder on the volar forearm for periods of up to 72 h. Exposure sites were stripped 20 times and the strips analyzed for metal content by inductively coupled plasma-mass spectroscopy with a detection limit for copper of 0.5 ppb. Untreated skin was stripped in the same fashion, to determine baseline copper levels for comparison with exposure values resulting from exposure in respective volunteers. Under occlusion with exclusion of air, up to 72 h copper values decreased from the superficial to the deeper layers of the stratum corneum with gradients increasing commensurately with occlusion time, characteristic of passive diffusion processes. From the tenth strip on, however, levels reverted to background values. Under semi-occlusion allowing access of air by covering the skin with "breathable" tape, initial copper values lay significantly above baseline values and concentration gradients increased proportionally with occlusion time. At 72 h, from the tenth to the twentieth strip reaching the glistening epidermal layer, copper values continued at constant levels, significantly above baseline values. The results indicate that, in contact with skin, copper will oxidize and may penetrate the stratum corneum after forming an ion pair with skin exudates. The rate of reaction seems to depend on contact time and availability of oxygen. A marked inter-individual difference was observed in baseline values and amounts copper absorbed.
本研究的目的是阐明一个长期存在的争议，即佩戴铜手镯是否对患有诸如关节炎等炎症性疾病的患者有益。对健康志愿者进行连续胶带剥离，以便在将金属粉末涂抹于掌侧前臂长达72小时后，在体内检测铜通过人体角质层的扩散情况。对暴露部位进行20次剥离，并通过电感耦合等离子体质谱法分析这些条带的金属含量，铜的检测限为0.5 ppb。以相同方式对未处理的皮肤进行剥离，以确定基线铜水平，以便与各志愿者暴露后的数值进行比较。在排除空气的封闭条件下，长达72小时内，角质层从表层到深层的铜含量下降，梯度随封闭时间相应增加，这是被动扩散过程的特征。然而，从第10条带开始，含量恢复到背景值。在半封闭条件下，用“透气”胶带覆盖皮肤以允许空气进入，初始铜含量显著高于基线值，浓度梯度随封闭时间成比例增加。在72小时时，从第10条带到第20条带到达有光泽的表皮层，铜含量持续保持恒定水平，显著高于基线值。结果表明，与皮肤接触时，铜会氧化，并可能在与皮肤渗出物形成离子对后穿透角质层。反应速率似乎取决于接触时间和氧气的可得性。在基线值和铜吸收量方面观察到明显的个体差异。
