UVA与UVB对人体黑素细胞生长的影响

[目的]探讨长波紫外线（UVA）和中波紫外线（UVB）照射人体黑素细胞作用的差异。[方法]以不同剂量UVA和UVB分别照射黑素细胞,用四甲基偶氮唑盐微量酶反应比色法（MTT）测量细胞增殖率,比色法测定酪氨酸酶活性,吸光度测定黑素含量的变化。[结果]人体黑素细胞经0-2．25J／cm^2UVA照射后,黑素含量和酪氨酸酶活性无明显改变,其中较高剂量UVA（〉1．8J／cm^2）可使黑素细胞存活率下降。0-0．06J／cm^2UVB能明显抑制黑素细胞存活率,并能激活酪氨酸酶和促进黑素细胞的黑素合成。[结论]离体水平UVB对黑素细胞的促黑素合成作用明显强于UVA。     

4种皮肤美白剂对小鼠黑素瘤细胞的功效评价

[目的]探讨4种常用皮肤美白剂的美白效果。[方法]选用B-16小鼠黑素瘤细胞,分别加入熊果苷、曲酸衍生物、BL-99和氢醌酯等4种常用皮肤美白剂3d后,用台盼蓝排斥法计数活细胞数,参照HideyaAndo等的方法测定酪氨酸酶活性和黑素含量。[结果]4种美白剂均可明显抑制B-16小鼠黑素瘤细胞生长和黑素合成,改变细胞形态。氢醌酯对细胞生长数量的控制作用最大,熊果苷最弱。熊果苷对酪氨酸酶活性具有抑制作用;氢醌酯虽可导致B-16细胞的酪氨酸酶活性呈下降趋势,但与对照组相比,差异无统计学意义(P>0.05);曲酸衍生物和BL-99均可致B-16细胞中酪氨酸酶活性呈波动性变化。[结论]4种皮肤美白剂均可抑制黑素细胞的生长和黑素合成,具有一定的美白效果,其机制可能不仅仅与酪氨酸酶活性有关。     

日本刺参胶原肽对B16黑素瘤细胞黑素合成的影响

目的:研究不同分子量日本刺参胶原肽A1(6000U相似文献   

三种美白剂对皮肤黑素细胞内酪氨酸酶活性抑制的探讨

[目的]探讨3种常用美白剂(对苯二酚、熊果苷、曲酸)对皮肤黑素细胞内酪氨酸酶活性的抑制作用。[方法] 利用B-16黑素瘤细胞株,分别加入美白剂5 d后,采用丙酮酸比色法测定细胞培养上清液胞浆酶(乳酸脱氢酶,LDH)释放水平,探讨美白剂的细胞毒性。采用冻融法提取培养细胞内酶液后,用L-酪氨酸作底物,测定美白剂对培养细胞内酪氨酸酶活性的影响。 [结果] 加入不同剂量(8、16、24、32、40、48μg/mL)美白剂后,对苯二酚对细胞有明显的毒性,影响细胞的生长。熊果苷、曲酸对培养细胞无明显的毒性,但对细胞内酪氨酸酶活性有明显的抑制作用。 [结论] 3种美白剂均能不同程度地抑制皮肤黑素细胞内酪氨酸酶活性,达到美白作用。     

烟酰胺对长波紫外线致人皮肤黑素细胞增殖的干预作用

目的研究烟酰胺对长波紫外线(UVA)致人皮肤黑素细胞增殖的干预作用。方法观察UVA(365nm)0.2cm2照射人皮肤黑素细胞后立即和照射后48h给予不同剂量烟酰胺后的细胞增殖率、细胞内钙离子浓度和Na+-K+、Ca2+-ATP酶活力。结果UVA照射黑素细胞后给予1.000mg/ml烟酰胺,24h即出现抑制黑素细胞增殖的作用,至48h时作用更为明显,自0.125mg/ml组就出现明显的抑制作用;烟酰胺1.25mg/ml可使黑素细胞内钙离子浓度增高;0.250mg/ml可使黑素细胞内Na+-K+、Ca2+-ATP酶活力增高,差异有统计学意义(P<0.05)。经UVA照射后立即给予不同浓度烟酰胺时,细胞内钙离子浓度和Na+-K+、Ca2+-ATP酶活力差异均无统计学意义(P>0.05)。结论UVA照射黑素细胞后即给予烟酰胺对经UVA照射后的保护作用较照射后经过一段时间再给予的作用效果明显。通过影响Ca2+及细胞内钙泵的活性很可能是烟酰胺干预黑素细胞增殖的途径之一。     

烟酰胺对长波紫外线照射黑素细胞黑素合成的干预

目的研究烟酰胺对长波紫外线（UVA）致人皮肤黑素细胞黑素合成的干预作用。方法观察0．2J／cm^2 UVA（365nm）照射人皮肤黑素细胞后，烟酰胺在不同剂量时对人皮肤黑素细胞中黑素合成和转运的干预作用。结果0．2J／cm^2 UVA照射后，黑素细胞中黑素含量明显增加，UVA照射后的人皮肤黑素细胞给予不同剂量的烟酰胺时，黑素细胞中黑素含量明显下降，10．0mmol／ml时作用更为明显。烟酰胺在有效抑制黑素含量的同时，对黑素细胞的细胞周期、细胞凋亡及DNA指数无明显影响；0．2J／cm^2 UVA照射后立即给予烟酰胺时，烟酰胺可以调节黑素细胞中mRNA的表达水平。结论烟酰胺能够拮抗UVA的致黑作用；10．0mmol／ml烟酰胺在干预UVA所致的黑素细胞致黑作用的同时，对黑素细胞的作用浓度是安全的；烟酰胺参与其中黑素的转运；鉴于烟酰胺拮抗UVA致黑作用的有效结果，烟酰胺有望用于防护UVA照射所引起的晒黑作用。     

太阳光及紫外线照射诱发M13mp2噬菌体DNA产生8-OHdG的作用

[目的 ]分析太阳光及长波紫外线 (UVA)、中波紫外线 (UVB)诱发Ml3mp2噬菌体DNA产生 8 羟基脱氧鸟苷(8 OHdG)的作用。 [方法 ]用太阳光、UVA和UVB照射处理M13mp2噬菌体样品 ,以HPLC EC检测DNA样品中的 8 OHdG。 [结果 ] 1、3、5h太阳光照射和 2 8、10 8、2 5 0、5 0 0kJ/m2 剂量UVA照射后的样品均可检测到 8 OHdG含量增加 ,并存在与照射剂量的依存关系。较高剂量 (2 6kJ/m2 )UVB照射也可引起 8 OHdG的产生。 [结论 ]太阳光照射致M13mp2噬菌体突变作用中 ,存在DNA的氧化损伤 ,主要是UVA的作用。     

长波紫外线对人皮肤成纤维细胞生长的影响

[目的 ]　观察长波紫外线 (UVA)对人皮肤成纤维细胞生长的影响 ,探讨皮肤光老化机制。　 [方法 ]　将原代培养的人皮肤成纤维细胞经UVA照射后 ,采用细胞成像、四唑盐比色实验 (MTT)、乳酸脱氢酶 (LDH)检测UVA对皮肤细胞的损伤。　 [结果 ]　随UVA照射剂量增加 ,成纤维细胞由正常细长梭状逐渐变圆、皱缩 ;UVA照射剂量为 9J/cm2 时 ,LDH从 ( 5 6.82± 4.78)U /dl上升至 ( 12 0 .40± 7.16U ) /dl;UVA照射剂量为 45J/cm2 时 ,成纤维细胞抑制率达到67.12 %。　 [结论 ]　UVA可损伤原代培养的人皮肤成纤维细胞     

苯并[a]芘对小鼠肝脏的氧化损伤作用研究

[目的]探讨不同剂量苯并[a]芘对小鼠肝脏的氧化损伤作用. [方法]用不同剂量(1 mg/kg,2.5mg/kg,6.25 mg/kg体重)苯并[a]芘对小鼠急性染毒,植物油为对照,2周后测定肝脏组织中超氧化物歧化酶(SOD)的活性、丙二醛(MDA)的含量,用单细胞凝胶电泳技术检测小鼠肝脏细胞DNA损伤情况. [结果]与对照组比较,各染毒组SOD活性均显著性下降(P＜0.05),MDA含量显著升高(P＜0.05),肝脏细胞彗星率随苯并[a]芘剂量增加而增加.彗星尾长随剂量增加而延长(P＜0.01). [结论]苯并[a]芘对小鼠肝脏有明显的氧化损伤作用.     

构树总黄酮对长波紫外线引起人角质形成细胞损伤的防护作用

目的研究长波紫外线(UVA)照射对人角质形成细胞的氧化损伤以及构树总黄酮(totalflavonoids of broussonetia papyrifera,TFBP)的防护效果。方法在人角质形成细胞培养的基础上,实验组在照射前加入不同剂量的TFBP,然后和处理组一起接受UVA照射,通过噻唑蓝(MTT)染色法检测细胞活性、裂解液中丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力,对构树叶提取物的抗氧化效果进行评价。结果随着UVA剂量的增高(0.46~2.76J/cm2),细胞的活性逐渐降低(96.3%~37.5%),添加TFBP10~200mg/L后,细胞活性升高,MDA含量由(5.14±0.58)nmol/mg pro降低到(2.98±0.14)nmol/mg pro,SOD活力由(23.09±3.91)U/mg pro增加到(34.50±1.59)U/mg pro,GSH-Px活力也有所升高。结论本试验条件下,UVA对人角质形成细胞有明显的氧化损伤,TFBP对这种氧化损伤有防护作用。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Fatigue and health in a seafaring population

Background Occupational fatigue is relatively common withinthe general population and has been linked to reduced performance,injury and longer term ill-health. Despite growing acknowledgementof this problem in the maritime sector, little research hasbeen conducted into the risk factors, prevalence and consequencesof seafarers' fatigue. Aims To examine the prevalence of fatigue among seafarers, identifypotential risk factors and assess possible links with poor performanceand ill-health. Methods Cross-sectional questionnaire survey of seafarers workingin the offshore oil support, short-sea and deep-sea shippingindustries. A number of tools were used including the fatiguesubscale of the profile of fatigue-related symptoms, the CognitiveFailures Questionnaire, the General Health Questionnaire andthe SF36 General Health scale. Results In all, 1855 questionnaires were completed giving anoverall response rate of 20%. Fatigue symptoms were associatedwith a range of occupational and environmental factors, manyunique to seafaring. Reporting a greater number of risk factorswas associated with greater fatigue [e.g. OR = 2.53 (1.90–3.35)for those with three or four risk factors and OR = 9.54 (6.95–13.09)for those with five or more risk factors]. There was also astrong link between fatigue and poorer cognitive and healthoutcomes, with fatigue the most important of a number of riskfactors, accounting for 10–14% of the variance. Conclusions Seafarers' fatigue could impact on safety withinthe industry and may be linked to longer term individual ill-health.It can only be addressed by considering how multiple factorscombine to contribute to fatigue.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.