接枝环氧树脂水分散液的合成、分离与表征

控制不同的反应条件,采用甲基丙烯酸、苯乙烯与环氧树脂在丙二醇丁醚/正丁醇溶剂中接枝共聚,合成了粒径在87～104nm范围的环氧树脂水分散液。通过环己烷/乙醇和丙酮两步萃取,对接枝共聚产物进行分离,用FTIR表征,并估算了接枝共聚物的组成。实验结果表明,所制备的粒径为纳米级的环氧树脂水分散液,具有良好的机械稳定性、冻融稳定性及贮存稳定性。ξ电位测定表明,产物在pH>8的条件下更为稳定。     

Dermatitis from hexavalent chromate in the accelerator of an epoxy sealant (PR1422) used in the aircraft industry

4 aircraft construction workers developed allergic contact dermatitis of the hands and forearms. The allergen was hexavalent chromate in the accelerating solution of an epoxy-based sealant (PR1422). Although chromate dermatitis from an epoxy resin has been described, epoxy system accelerators are a hitherto unrecognized source of occupational chromate dermatitis.     

大鼠长期服苯妥英锌或苯妥英钠对体内锌铜代谢的影响

本文用原子吸收分光光度法测定了大鼠分别服用苯妥英锌和苯妥英钠13周后(每天剂量为12mg/kg体重),肝脏、全脑、齿龈和血清锌铜的含量。苯妥英锌使齿龈和肝脏锌分别增高80％和49％,全脑和血清锌分别降低39％和35％,而苯妥英钠使齿龈和肝脏锌分别降低70％和28％,血清锌增高41％。两药均使全脑和齿龈铜降低。     

Occupational allergic contact dermatitis and composition of acrylates in dentin bonding systems

Background Dentin-bonding systems contain sensitizing acrylates. They are increasingly used in dentistry, but only few cases of allergy have been encountered. Objective This study reports observations on eleven patients sensitized by acrylates in dentin-bonding compounds. Furthermore, the composition of dentin-bonding products was analysed and compared with the information given in the material safety data sheets. Methods Patch testing was performed to reveal allergic contact dermatitis, and chamber provocation tests to reveal possible respiratory sensitivity. Gas chromatography/mass spectrometry was used to analyse the chemical composition of the bonding products. Results The most common sensitizer in our material of eleven patients was 2-hydroxyethyl methacrylate (2-HEMA). Another putative sensitizer, BIS-GMA, used in dentin adhesives, did not cause sensitization. The typical allergic dermatitis localized to the fingertips (pulpitis). Seven of the eleven patients also developed paresthesia of the fingertips. One patient with positive patch test reactions to (meth)acrylates had pharyngitis hut no skin symptoms. One patient was sensitized because she had been patch tested with too high a concentration (undiluted) of dentin-bonding components. Material safety sheets gave inaccurate or wrong information about the contents. Conclusion Dentin-bonding acrylates are strong sensitizers, and even a single exposure may sensitize.     

复合树脂预热的研究现状和临床应用

复合树脂作为临床常用牙科充填材料存在耐磨性差、聚合收缩大和牙本质边缘适应性不佳等问题。近年有研究发现预热可以改善复合树脂的性能,本文就预热复合树脂对其单体转化率、边缘微渗漏、机械性能以及牙髓的影响等方面进行探讨,以供临床参考。     

Absorption of chemicals through compromised skin

Skin is an important route of entry for many chemicals in the work place. To assess systemic uptake of a chemical in contact with the skin, quantitative information on dermal absorption rates of chemicals is needed. Absorption rates are mainly obtained from studies performed with intact, healthy skin. At the work place, however, a compromised skin barrier, although not necessarily visible is common, e.g. due to physical and chemical damage. As reviewed in this article, there are several lines of evidence that reduced integrity of the skin barrier may increase dermal absorption of chemicals in the occupational setting. An impaired skin barrier might lead not only to enhanced absorption of a specific chemical, but also to entrance of larger molecules such as proteins and nanoparticles which normally are not able to penetrate intact skin. In addition to environmental influences, there is increasing evidence that some individuals have an intrinsically affected skin barrier which will facilitate entrance of chemicals into and through the skin making these persons more susceptible for local as well for systemic toxicity. This review addresses mechanisms of barrier alteration caused by the most common skin-damaging factors in the occupational settings and the consequences for dermal absorption of chemicals. Furthermore, this review emphasizes the importance of maintained barrier properties of the skin.     

小肠吸收胆固醇的分子生物学研究进展

胆固醇通过分布于十二指肠和近段空肠黏膜上皮细胞刷状缘膜的Niemann—Pick C1样蛋白1摄取，ATP结合盒G5、G8抑制小肠对胆固醇的摄取过程。进入上皮细胞的胆固醇大多数被乙酰辅酶A，胆固醇转乙酰基酶2酯化，随后通过组装形成乳糜微粒，经淋巴管进入血循环；另一部分胆固醇则以未酯化形式直接进入血循环形成高密度脂蛋白颗粒。这些过程受核受体——肝脏X受体的调控。年龄、性别、黏膜屏障和小肠传输速度也影响胆固醇的吸收。     

灯盏花素大鼠小肠吸收特性的研究

目的 :研究灯盏花素最佳吸收部位和探讨灯盏花素的吸收机理。方法 :采用大鼠在体循环方法研究灯盏花素的小肠吸收和肠壁通透性。结果 :在 5 0～ 40 0ug/ml浓度范围内吸收量与浓度呈线性关系 ,无高浓度饱和现象 ,P值基本保持不变 ;在pH 6 0至pH 7 4范围内吸收不受pH影响 ;在各肠段的百分吸收率和肠壁通透系数均无明显差异 ;促吸剂Tween 80和大豆磷脂对灯盏花素具有明显的促进吸收作用 ;吸收动力学参数为 :ka=0 0 163± 0 0 0 64min-1,ke=0 0 668± 0 0 15min-1。结论 :灯盏花素在大鼠小肠主要以被动扩散方式吸收 ,提高药物溶解度和采用促吸方法提高通透性 ,将能有效地促进灯盏花素的吸收 ,达到提高生物利用度的目的 ;灯盏花素在整个肠段均有吸收 ,可以将灯盏花素研制成缓释片剂     

Accumulation of toxic metals (Pb and Cd) in the sea urchin Diadema aff. antillarum Philippi, 1845, in an oceanic island (Tenerife,Canary Islands)

This document shows the results obtained from a study on the concentration of toxic heavy metals in the internal tissue and exoskeleton of sea urchins, collected from their natural habitat. The levels of lead and cadmium were measured by Graphite Furnace Atomic Absorption Spectrometry. The mean concentrations of lead and cadmium in the internal tissue were 304.04 and 260.54 μg/kg respectively, whereas in the shell they were 185.02 and 142.48 μg/kg. We also performed a statistical analysis of the differences in the distribution of metals between their exoskeleton and their internal content, a correlation study of the metal content in internal tissue and shell and sampling areas, and a correlation study between the metal content and sample size. Since the sea urchin Diadema antillarum presents a wide range of variation in metal content, this study suggests that this species is an excellent bioindicator of heavy metal contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

卡马西平片体外溶出度与体内吸收相关性

目的：考察卡马西平（ＣＢＺ）片溶出度与体内吸收的相关性。方法：应用ＺＲＳ－４溶出度仪测定卡马西平片的溶出度。４名男性健康志愿性ｐｏ单剂量２００ｍｇＣＢＺ用ＴＤｘ分析仪测定血药浓度，并按照Ｗａｇｎｅｒ－Ｎｅｌｓｏｎ公式计算药物吸收分数。结果：体外溶出度与体内药物吸收分数的相关系数ｒ＝０．９２６１，体外溶出度与体内药物吸收分数的相关系数ｒ＝０．９９７７。结论：ＣＢＺ片体外溶出度与体内吸收有较好的相关性