A New Method for Estimating Dermal Absorption from Chemical Exposure. 3. Compared with Steady-State Methods for Prediction and Data Analysis

Purpose. This paper compares unsteady-state and steady-state methods for estimating dermal absorption or analyzing dermal absorption data. The unsteady-state method accounts for the larger absorption rates during short exposure times as well as the hydrophilic barrier which the viable epidermis presents to lipophilic chemicals. Methods. Example calculations for dermal absorption from aqueous solutions are presented for five environmentally relevant chemicals with molecular weights between 50 and 410 and log₁₀K_ow between 0.91 and 6.8: chloromethane, chloroform, chlordane, 2,3,7,8-TCDD, and dibenz(a,h)anthracene. Also, the new method is used to evaluate experimental procedures and data analyses of in vivo and in vitro permeation measurements. Results. In the five example cases, we show that the steady-state approach significantly underestimated the dermal absorption. Also, calculating permeability values from cumulative absorption data measured for exposure periods less than 18 times the stratum corneum lag time will overestimate the actual permeability. Conclusions. In general, steady-state predictions of dermal absorption will underestimate dermal absorption predictions which consider unsteady-state conditions. Permeability values calculated from data sets which include unsteady-state data will be incorrect. Strategies for analyzing in vitro diffusion cell experiments and confirming steady state are described.     

Monitoring of skin response to sodium lauryl sulphate: clinical scores versus bioengineering methods

The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)     

一种适用于大规模高效快速分离培养人头皮毛乳头细胞的方法

目的:寻求适合于毛囊组织工程的大规模高效快速分离培养人头皮毛乳头细胞的方法。方法:将含有毛囊中下部的皮下组织剪碎,加入胶原酶Ⅰ消化2h,悬液经400目筛网过滤,收集被筛网截留的毛乳头进行培养,计算其贴壁率,绘制细胞生长曲线,并与显微解剖法相比较。结果:用这种方法成功分离培养了人头皮毛乳头细胞。结论:消化过滤法是一种能够大规模高效、快速分离培养人头皮毛乳头细胞的方法。     

十二烷基硫酸钠制备脱细胞真皮基质的实验研究

目的 探讨十二烷基硫酸钠制备脱细胞真皮基质的最佳浓度及作用时间.方法 取临床截肢患者废弃的皮肤,分成90块,随机分成6组,每块约1 cm×1 cm,分别置于0.1%、0.25%、0.5%、1.0%、2.5%、5.0%十二烷基硫酸钠溶液中脱细胞,每隔8 h取材一次,分别取材15次.取材标本行大体和组织学观察.结果 肉眼观察十二烷基硫酸钠作用8 h后,0.25%组可将表皮与真皮完整分离;光镜检查显示0.25%十二烷基硫酸钠在作用40 h后,能将真皮内的细胞及细胞碎片脱净,形成脱细胞真皮基质.制备的脱细胞真皮基质,主要由胶原纤维网架构成,其他组作用120 h也无法形成真正的脱细胞真皮基质.结论 十二烷基硫酸钠制备脱细胞真皮基质的最佳浓度为0.25%,最佳时间为40 h.与其他方法比较,具有简便、快捷、有效、价廉、宜推广等特点,可为临床急诊的修复争取宝贵的时间.     

微囊化吲哚美辛片剂的研讨

以明胶-CAP 为囊材,经复凝聚法制备吲哚美辛微囊,再按所筛选的最佳处方制备微囊化片剂。该片与市售片相比,体外 T_(50)延长约5.6倍,家兔体内达峰时间滞后,能明显减轻对大鼠胃的刺激性。     

人毛乳头细胞条件培养液治疗斑秃的临床观察

目的：人毛乳头细胞条件培养液治疗斑秃患者的临床观察。方法：用人毛乳头细胞条件培养液治疗100例斑秃患者，并分别选择其中53例和30例作去炎松组和空白组自身对照。结果：人毛乳头细胞条件培养液组、去炎松组和空白组治愈率分别为75％、51％、10％，有效率分别为97％、72％、30％，人毛乳头细胞条件培养液组其治愈率和有效率均明显高于去炎松组和空白组（P〈0．05）。结论：人毛乳头细胞条件培养液对斑秃患者有明显的治疗作用。     

眼刺激试验替代方法研究进展

由于动物眼刺激试验 (Draizetest)本身存在的问题和“3R”运动的兴起 ,各国广泛开展了动物眼刺激试验替代方法的研究和验证试验。各种替代方法作用机制不一 ,优缺点各异 ,故需要一组互补性体外试验来对化学物质的眼刺激性进行评价     

Review of long-term adverse effects associated with the use of chemically-modified animal and nonanimal source hyaluronic acid dermal fillers

Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as “redefining” dermal fillers in the fields of dermatology and cosmetic facial surgery. Although hyaluronic acid-based dermal fillers have a low overall incidence of long term side effects, occasional adverse outcomes, ranging from chronic lymphoplasmacytic inflammatory reactions to classic foreign body-type granulomatous reactions have been documented. These long-term adverse events are reviewed.     

人毛乳头细胞凝集性生长差异表达基因cDNA文库的构建

目的 构建毛乳头细胞凝集性生长状态下差异表达基因的消减cDNA文库。方法 分别提取凝集性生长和非凝集性生长状态下毛乳头细胞中的总RNA，应用SMART cDNA合成技术和抑制性消减杂交技术分离毛乳头细胞凝集性生长状态下差异表达基因的cDNA片段并建立消减cDNA文库；利用PCR对随机挑选的100个白色菌落进行插入片段的验证，对其中证实有插入片段的30个克隆进行cDNA斑点杂交验证。结果 所构建的消减cDNA文库扩增后得到320个阳性克隆，随机挑选的100个阳性克隆中95％的均有长度在100—600bp的插入片段，cDNA斑点杂交验证显示27个(90．0％)克隆为阳性。结论 结合SMART cDNA合成技术，应用抑制性消减杂交成功地构建了毛乳头细胞凝集性生长差异表达基因消减cDNA文库，为进一步筛选和克隆毛乳头细胞凝集性生长相关基因奠定了基础。     

自体皮源奇缺条件下瘢痕挛缩畸形的晚期临床修复

目的寻找对烧伤后畸形伴自体皮源奇缺患进行晚期修复的新方法。方法5例特重度、特大面积烧伤患治愈后伴较严重畸形，且自体皮源奇缺。采用柔软成熟的瘢痕皮肤作为修复的皮源，用扩张器扩张瘢痕皮肤后，切取中厚瘢痕皮片进行修复；不宜行瘢痕皮肤扩张术时，切取刃厚瘢痕皮片与异体脱细胞真皮基质组成复合皮进行修复。观察两种方法的疗效。结果所移植的扩张瘢痕皮片和复合皮均成活，功能和外形恢复良好，远期疗效近似正常自体中厚皮移植。结论采用不同厚度的瘢痕皮片修复烧伤畸形是可行的，可扩大自体皮源。此法对于皮源奇缺的瘢痕患尤其适用。