Evaluation of ex vivo melanogenic response to UVB,UVA, and visible light in facial melasma and unaffected adjacent skin

BackgroundThe independent role of solar radiation in the differential melanogenesis between melasma and adjacent skin is unknown.ObjectivesTo assess the melanogenic responses of skin with facial melasma and of the adjacent skin to UVB, UVA, and visible light, in an ex vivo model.MethodsThis was a quasi-experimental study involving 22 patients with melasma. Facial melasma and adjacent skin samples were collected and stored in DMEM medium, at room temperature. One fragment was placed under the protection from light, while another was exposed to UVB, UVA, and visible light (blue-violet component): 166 mJ/cm², 1.524 J/cm², and 40 J/cm², respectively. Subsequently, all samples were kept for 72 hours in a dark environment and stained by Fontana-Masson to assess basal layer pigmentation, dendrites, and melanin granulation.ResultsEffective melanogenesis was observed in the basal layer in melasma and in the normal adjacent skin after all irradiations (p < 0.01), with the following median increment: UVB (4.7% vs. 8.5%), UVA (9.5% vs. 9.9%), and visible light (6.8% vs. 11.7%), with no significant difference between anatomical sites. An increase in melanin granulation (coarser melanosomes) was observed only after irradiation with UVA and only in the skin with melasma (p = 0.05). An increase in the melanocyte dendrite count induced by UVB radiation was observed in both anatomical sites (p ≤ 0.05).Study limitationsUse of an ex vivo model, with independent irradiation regimes for UVB, UVA, and visible light.ConclusionsMelanogenesis induced by UVB, UVA, and visible light was observed both in melasma and in the adjacent skin. The morphological patterns suggest that different irradiations promote individualized responses on the skin with melasma.     

外源性胆绿素对中波紫外线诱导的角质形成细胞光损伤的保护作用和机制

【摘要】 目的 探讨外源性胆绿素对中波紫外线（UVB）照射的HaCaT细胞光损伤的保护作用。方法 将HaCaT细胞分为加入0、0.1、1、10 μmol/L胆绿素并照射UVB的UVB组、0.1 μmol/L UVB组、1 μmol/L UVB组、10 μmol/L UVB组及不做处理的对照组。UVB照射剂量为30 mJ/cm2，照射后继续培养24 h，分别检测细胞活性氧（ROS）水平、超氧化物歧化酶（SOD）活力、丙二醛（MDA）含量，ELISA法检测各组细胞的炎症因子白细胞介素6（IL-6）、IL-8水平。多组间均数比较采用单因素方差分析，组间两两比较采用LSD-t检验。结果 UVB组、0.1 μmol/L UVB 组、1 μmol/L UVB组、10 μmol/L UVB组、对照组细胞ROS水平（3 613.33 ± 206.61、2 958.67 ± 193.87、2 678.33 ± 178.24、2 274.67 ± 118.81、1 905.67 ± 250.25）、SOD活力（24.41 ± 1.78、28.96 ± 2.21、29.75 ± 1.75、30.19 ± 2.29、37.52 ± 2.31）、MDA含量（5.61 ± 0.32、5.46 ± 0.55、4.65 ± 0.22、2.55 ± 0.93、1.31 ± 0.05）、IL-6水平、IL-8水平差异均有统计学意义（F值分别为 34.02、57.36、214.09、29.73、11.40，均P < 0.05），UVB组ROS水平、MDA含量及IL-6、IL-8水平均高于另4组（均P < 0.05），SOD活力均低于另4组（均P < 0.05）。结论 外源性胆绿素减轻UVB引起的HaCaT细胞的氧化损伤、减轻炎症反应和抑制脂质过氧化作用，对细胞光损伤有一定的保护作用。     

Decreased efficacy of UV inactivation of Staphylococcus aureus after multiple exposure and growth cycles

UV disinfection is a relatively simple and cost-efficient disinfection method, especially for in-home greywater treatment. In this study, a bench scale experiment was performed using a LED collimated UV-C beam with a peak wavelength of 256?nm to determine if potentially pathogenic bacteria such as Staphylococcus aureus may become enriched in a semi-recirculating greywater system with UV as the sole disinfection step. A statistically significant (P?<?0.001) decreasing trend in UV-C efficacy was observed between the 1st and 6th UV exposure-growth cycles of S. aureus (ATCC 25923), resulting in a 1.5 decrease in log₁₀ removal (P?<?0.00000) by the 5th iteration. An eleven-point dose-response curve of the 7th iteration of S. aureus was estimated and compared to the dose-response curve of the original strain; due to a longer apparent shoulder period and a decay constant of lesser degree, the dose required for a 4-log reduction of the enriched S. aureus was estimated to be ～1.9 times greater (22.0?mJ?cm^?2 versus 11.8?mJ?cm^?2). However, experimental results with S. epidermidis (ATCC 12228) and two wild strains, S. aureus and S. warneri, exhibited no trend of increased resistance. UV doses exceeding 20?mJ?cm^?2 are generally sufficient in achieving a 4-log reduction of bacteria in drinking water systems; however, the results exhibited in this study suggest that when recirculation is involved, there may be a need for UV doses exceeding what is necessary for a 4-log reduction to suppress the enrichment of strains which could pose a public health risk.     

庆大霉素-藻酸钙三维缓释微球的药物释放研究

目的研制庆大霉素一藻酸钙三维缓释微球并调控其庆大霉素的释放。使其达到长期局部抗菌的效果。方法制作不同浓度T、S、U组庆大霉素-藻酸钙缓释凝珠,与庆大霉素-骨水泥颗粒Y组进行庆大霉索释放情况比较。通过不同时间点抽取浸泡液,送紫外分光光度法（UV）及金黄色葡萄球菌（SA）培养检测,由此计算出各组包封率、释放率,绘制庆大霉素释放曲线。结果4组样品（微生物法）的包封率及30d药物释放率分别为：U组（53．99％、36．31％）,S组（39．62％、27．55％）。T组（34．20％、30．83％）,Y组（100．00％、48．49％）。U组的包封率较高,30d释放庆大霉素的总量较大,更接近Y组。4组间差异有统计学意义（P〈0．01）。U、Y组庆大霉素的释放明显高于S、T组的释放。各组30d内庆大霉素的浓度几乎都能超过金黄色葡萄球菌的最低抑菌浓度（MIC）．即〉2μg／mI。结论U组载药缓释凝珠30d内的庆大霉索释放较为理想。可作为BMSCs的三维培养支架。     

紫外线灯管的安装方法与消毒效果

报告了目前国内外常见的４种紫外线灯管的安装与消毒效果，以无罩悬空吊式为最佳。在一间２４．５ｍ３的换药室内，照射１ｈ即可达到＜Ⅲ类标准的细菌数。而有罩悬空吊式，推车活动式，固定贴墙式均因其罩背面空间阻挡了２０％～４０％的紫外线照射，从而降低了杀菌效果，需消毒２ｈ才达到Ⅲ类标准，也只能维持１ｈ。统计学处理，无罩悬空吊式消毒效果比其它安装方法差异有显著意义。     

3种空气消毒方法对供应室无菌区消毒效果比较

目的 探讨紫外线灯、三氧杀菌机、多功能动态杀菌机3种消毒方法对供应室无菌区空气消毒效果.方法 采用现场实验法对3种设备在空气消毒中的效果进行比较观察.结果 3种消毒方法在无人条件下消毒效果无显著差别(p＜0.05),但在有人条件下,仅多功能动态杀菌机能达到标准.结论 3种空气消毒法都是控制医院感染的重要手段,但紫外线灯和三氧杀菌机消毒不能在有人条件下消毒.     

紫外线、电磁场及药物治疗对白兔化疗性静脉炎的影响

目的 观察紫外线、电磁场及药物治疗对白兔化疗性静脉炎的影响。方法 向白兔耳缘静脉内注入长春瑞滨注射液，使其局部皮肤出现红肿热痛，从而制作化疗性静脉炎模型。共有12只日本大耳白兔制模成功。随机分为对照组、紫外线治疗组、电磁治疗组、药物治疗组，每组各3只白兔（共6只兔耳）。紫外线治疗组、电磁治疗组及药物治疗组分别给予紫外线照射、电磁辐射及药物治疗；对照组白兔未给予任何特殊处理。于实验进行4d后，分别对各组兔耳进行肉眼观察及病理组织学检查。结果 肉眼观察发现，紫外线治疗组与电磁治疗组症状改善较明显（P〈0．01），药物治疗组也有改善趋势，但与对照组比较，差异无统计学意义（P〉0．05）。经病理学检查后发现，紫外线治疗组和电磁治疗组的水肿消除作用明显（P〈0．01），药物治疗组水肿也有一定程度减轻，但与对照组比较，差异无统计学意义（P〉0．05）；电磁辐射还有一定的抑制纤维组织增生作用（与对照组比较，P〈0．05）。结论 紫外线治疗和电磁辐射对化疗性静脉炎均有良好的消炎、消肿功效．而且电磁辐射还能抑制纤维组织的增生。     

Accuracy of computer-aided design/computer-aided manufacturing–generated dental casts based on intraoral scanner data

Background.Little is known about the accuracy of physical dental casts that are based on three-dimensional (3D) data from an intraoral scanner (IOS). Thus, the authors conducted a study to evaluate the accuracy of full-arch stereolithographic (SLA) and milled casts obtained from scans of three IOSs.Methods.The authors digitized a polyurethane model using a laboratory reference scanner and three IOSs. They sent the scans (n = five scans per IOS) to the manufacturers to produce five physical dental casts and scanned the casts with the reference scanner. Using 3D evaluation software, the authors superimposed the data sets and compared them.Results.The mean trueness values of Lava Chairside Oral Scanner C.O.S. (3M ESPE, St. Paul, Minn.), CEREC AC with Bluecam (Sirona, Bensheim, Germany) and iTero (Align Technology, San Jose, Calif.) casts were 67.50 micrometers (95 percent confidence interval [CI], 63.43-71.56), 75.80 μm (95 percent CI, 71.74-79.87) and 98.23 μm (95 percent CI, 94.17-102.30), respectively, with a statistically significant difference among all of the scanners (P < .05). The mean precision values were 13.77 μm (95 percent CI, 2.76-24.79), 21.62 μm (95 percent CI, 10.60-32.63) and 48.83 μm (95 percent CI, 37.82-59.85), respectively, with statistically significant differences between CEREC AC with Bluecam and iTero casts, as well as between Lava Chairside Oral Scanner C.O.S. and iTero casts (P < .05).Conclusion.All of the casts showed an acceptable level of accuracy; however, the SLA-based casts (CEREC AC with Bluecam and Lava Chairside Oral Scanner C.O.S.) seemed to be more accurate than milled casts (iTero).Practical Implications.On the basis of the results of this investigation, the authors suggested that SLA technology was superior for the fabrication of dental casts. Nevertheless, all of the investigated casts showed clinically acceptable accuracy. Clinicians should keep in mind that the highest deviations might occur in the distal areas of the casts.