维生素E、C对紫外线辐射致皮肤细胞氧化性损伤的保护作用

以丙二醛（MDA）为指标,观察小鼠皮肤细胞体外经紫外线照射后脂质过氧化水平的变化。结果表明:小鼠皮肤细胞中的MDA含量随照射时间的延长而增加;同时观察了用VE和VC作保护剂,以同样的照射条件处理小鼠皮肤细胞后,MDA含量明显低于非保护组（P＜0.01）。结果说明紫外线对小鼠皮肤细胞具有一定的氧化毒性,维生素E、C具有抗紫外线所致的氧化性损伤的作用。     

Repair of DNA damage in light sensitive human skin diseases

Summary Repair of UV-light induced DNA damage and changes in the semiconservative DNA synthesis were studied by in vitro autoradiography in the skin of patients with lightdermatoses (polymorphous light eruption, porphyria cutanea tarda, erythropoietic protoporphyria) and xeroderma pigmentosum as well as in that of healthy controls. In polymorphous light eruption the semiconservative DNA replication rate was more intensive in the area of the skin lesions and in the repeated phototest site, the excision repair synthesis appeared to be unaltered. In cutaneous porphyrias a decreased rate of the repair incorporation could be detected. Xeroderma pigmentosum was characterized by a strongly reduced repair synthesis.     

The Ro 60 kDa autoantigen: insights into cellular function and role in autoimmunity

An RNA-binding protein, the Ro 60 kDa autoantigen, is a major target of the immune response in patients suffering from two systemic rheumatic diseases, systemic lupus erythematosus and Sjogrens syndrome. In lupus patients, anti-Ro antibodies are associated with photosensitive skin lesions and with neonatal lupus, a syndrome in which mothers with anti-Ro antibodies give birth to children with photosensitive skin lesions and a cardiac conduction defect, third degree heart block. In vertebrate cells, the Ro protein binds small RNAs of unknown function known as Y RNAs. Although the cellular function of Ro has long been mysterious, recent studies have implicated Ro in two distinct processes: small RNA quality control and the enhancement of cell survival following exposure to ultraviolet irradiation. Most interestingly, mice lacking the Ro protein develop an autoimmune syndrome that shares some features with systemic lupus erythematosus in patients, suggesting that the normal function of Ro may be important for the prevention of this autoimmune disease. In this review, we summarize recent progress towards understanding the role of the Ro 60 kDa protein and discuss whether the cellular function of Ro could be related to certain manifestations of lupus in patients.Abbreviations RNP Ribonucleoprotein - RRM RNA recognition motif - SCLE Subacute cutaneous lupus erythematosus - SLE Systemic lupus erythematosus - snRNP Small nuclear ribonucleoprotein - SS Sjogrens syndrome - UV Ultraviolet - VWFA von Willebrand factor A     

Study of the ultraviolet emission of the electrode coatings of arc welding

The optical emission properties of several minerals components employed in electrode coatings of arc welding have been investigated. The X-ray diffraction analysis shows that the composition of 14 commercial electrode coatings collected from different countries (Spain, France, UK, Poland, Argentina and Germany), consists of quartz, calcite, sodium and potassium rich feldspars, muscovite and rutile. The natural thermal stimulated luminescence (TSL) of these mineral phases, measured in the range of 200-800 nm at different temperatures (from room temperature to 400 degrees C) displays UV-A (wavelengths of 320 nm to 400 nm) and UV-B (from 280 nm to 320 nm) emissions, with the exception of rutile. The UV-B radiation, commonly described as the most dangerous form of radiation to human life, is here associated with structural defects in the crystallographic lattice of the mineral components of electrode coatings.     

Evidence that arsenite acts as a cocarcinogen in skin cancer

Inorganic arsenic (arsenite and arsenate) in drinking water has been associated with skin cancers in several countries such as Taiwan, Chile, Argentina, Bangladesh, and Mexico. This association has not been established in the United States. In addition, inorganic arsenic alone in drinking water does not cause skin cancers in animals. We recently showed that concentrations as low as 1.25 mg/l sodium arsenite were able to enhance the tumorigenicity of solar UV irradiation in mice. The tumors were almost all squamous cell carcinomas (SCCs). These data suggest that arsenic in drinking water may need a carcinogenic partner, such as sunlight, in the induction of skin cancers. Arsenite may enhance tumorigenicity via effects on DNA repair and DNA damage-induced cell cycle effects, leading to genomic instability. Others have found that dimethlyarsinic acid (DMA), a metabolite of arsenite, can induce bladder cancers at high concentrations in drinking water. In those experiments, skin cancers were not produced. Taken together, these data suggest that arsenite (or possibly an earlier metabolite), and not DMA, is responsible for the skin cancers, but a second genotoxic agent may be a requirement. The differences between the US and the other arsenic-exposed populations with regard to skin cancers might be explained by the lower levels of arsenic in the US, less sun exposure, better nutrition, or perhaps genetic susceptibility differences.     

The physicochemical characteristics and bioavailability of indomethacin from beta-cyclodextrin, hydroxyethyl-beta-cyclodextrin, and hydroxypropyl-beta-cyclodextrin complexes

In an effort to improve the bioavailability of the insoluble drug indomethacin, three complexes were prepared with indomethacin and the soluble complexing agents β-, hydroxyethyl-β-, and hydroxypropyl-β-cyclodextrin. The indomethacin content was similar among the complexes (P≤0.05). To confirm complex formation, each complex was characterized by ultraviolet, infrared, nuclear-magnetic resonance, powder X-ray diffraction, and differential-scanning calorimetry techniques. Powder diffraction studies show the β-cyclodextrin complex was polycrystalline, and the hydroxyethyl- and hydroxypropyl-β-cyclodextrin complexes were amorphous. Phase-solubility analysis confirmed the formation of complexes and suggested the three complexes were bound similarly. Solubility studies show complexation increased indomethacin solubility, and the hydroxyethyl- and hydroxypropyl-β-cyclodextrin complexes were more soluble than the β-cyclodextrin complex in 0.1N hydrochloric acid and distilled water. Dosage forms were prepared by encapsulating the complexes without the addition of excipients. Dissolution studies show the encapsulated β- and hydroxyethyl-β-cyclodextrin complexes had superior dissolution when compared to the hydroxypropyl-β-cyclodextrin and Indocin^® (50 mg) capsules. Bioavailability studies were performed by administering the indomethacin complex or Indocin capsules to male-albino, New Zealand rabbits. Indomethacin plasma-time concentration data fit best to a compartment-independent model for all capsule formulations. Bioavailability comparisons by ANOVA show no significant difference (P≤0.10) in the peak-plasma time and peak concentration among the capsule formulations. The area-under-the-curve for the β-cyclodextrin complex capsules was found to be significantly higher (P≤0.10) than all other capsule formulations. In conclusion, the bioavailabilty of indomethacin was improved by complexation with only β-cyclodextrin. No correlations were found among the bioavailability, solubility, and dissolution results.     

Excimer laser for pacemaker and defibrillator lead extraction: techniques and clinical results

. Pacing and defibrillation leads may need to be removed for several reasons including infection, interference with others leads, lack of vascular access or redundancy. However, the removal of chronically implanted leads is a major technical challenge because of the extensive adhesions that develop along the course of the leads over time. The techniques to remove chronic leads have been greatly facilitated by the development of an excimer laser sheath. We undertook an analysis of our experience with laser extraction in the first 50 leads attempted. An excimer laser sheath system, developed by the Spectranetics Corporation, was used to extract 50 chronically implanted leads in 34 patients. The mean patient age was 64±12 years, all were male and the average duration that the leads had been implanted was 5.0±3.9 years. Two-thirds of the leads were pacemaker and one-third were defibrillator leads. There was a 100% clinical success rate and 48 of the 50 leads were completely removed. There were no major complications. There was one minor complication of subclavian vein thrombosis and two haemodynamically non-significant episodes of air embolism. The main limitation observed was failure of the excimer laser sheath to advance in 18% of cases, probably due to the presence of calcified adherences on leads. Two strategies were found useful to deal with this problem: under the clavicle stainless-steel sheaths were used to break up calcified adherences and within the venous system the laser sheath was upsized in order to advance over the calcification on the lead. It was concluded that excimer laser has greatly facilitated the removal of chronically implanted pacemaker and defibrillator leads. There is a high success rate and low complication rate in our experience. The main limitation of laser is the presence of calcified adherences.     

毫米波与红外线和紫外线联合治疗烧伤创面的临床观察

目的探讨毫米波、红外线、紫外线联合应用对烧伤的治疗效果。方法将80例深Ⅱ度烧伤患者随机分为4组:毫米波治疗组(A组)、红外线治疗组(B组)、紫外线治疗组(C组)、联合治疗组(D组),分别采用毫米波、红外线、紫外线及联合应用治疗烧伤创面,观察临床效果。结果治疗14d后对4组疗效进行比较,D组与A、B、C组疗效间差别均有统计学意义(P<0.05),A、B、C3组比较疗效间差别无统计学意义(P>0.05)。结论3种仪器联合应用能使深Ⅱ度烧伤创面的愈合加快,疗效明显优于单独应用毫米波、红外线、紫外线。     

黄芩苷提取工艺研究

目的:对现有黄芩苷提取工艺中的水提、酸沉、水洗、醇洗各参数进行优化,为今后黄芩苷的提取和纯化提供参考。方法:以黄芩苷含量为指标,通过正交设计实验,对影响水提、酸沉、水洗、醇洗工艺的因素进行考察,并进行方差分析。结果:确定了提取黄芩苷的最佳工艺条件。结论:该提取工艺合理,黄芩苷收率高,质量易于控制。