FOLLOW UP ON SYSTEMIC INFLUENCE OF PARTIAL PRE-IRRADIATION ON UV-TUMORIGENESIS

Abstract— In a previous paper we presented experimental data which showed that partial pre-irradiation of a mouse enhanced subsequent UV-tumorigenesis in formerly unexposed skin areas: a systemic effect. In those experiments pre-irradiation was carried out up to the point where tumors started to appear in the pre-irradiated skin areas. Here we present the results of an experiment in which pre-irradiation was discontinued long before the appearance of tumors. The systemic effect induced by the pre-irradiation remained detectable, though-it was weaker than in the previous experiment. It is suspected that the observed systemic effect affects the initiation of tumors rather than the growth. A discussion is presented on how changes in initiation may best be detected, which may also prove to be useful for the design of other comparative studies on UV-tumorigenesis.     

THE SYNERGISTIC INFLUENCE OF A PRE-IRRADIATION ON THE PHOTOINHIBITTON OF GHERKIN SEEDLINGS

Abstract— A pre-irradiation of etiolated gherkin seedlings increases the effect of a subsequent irradiation with red light, whereas it does not influence the inhibitive effect of blue light. Blue and far red radiation are more active as a pre-irradiation than red light. It is concluded that at least two photoreactions are involved in the control of the elongation of the gherkin hypocotyl and that the blue, far red sensitive reaction has a synergistic effect on the red sensitive (Phytochrome mediated) reaction.     

制膜液黏度对单皮层PVDF中空纤维膜纺制的影响

以二甲基乙酰胺(DMAc)为溶剂,制备聚偏氟乙烯(PVDF)浓度为15%的制膜液,考察了DMAc同时作为内凝胶浴时膜结构的变化.为保持纺膜过程中的稳定性,分别考察了添加剂LiCl、水以及表面活性剂对制膜液黏度的影响.实验发现添加LiCl可以大大提高制膜液的黏度,而水作为添加剂时对黏度的影响与制膜液本身的浓度有关.在不提高制膜液浓度的基础上,通过提高制膜液黏度克服了膜在纺制过程中的不稳定问题,得到阻力较小的,指状孔贯穿的单外皮层中空纤维膜.     

THE EFFECT OF SYSTEMIC CYCLOSPORIN A ON A HAIRLESS MOUSE MODEL OF PHOTOAGING

The mechanisms that cause skin wrinkling in response to chronic exposure to sunlight are unknown. We investigated the possibility that wrinkling of Skh-1 hairless mice is associated with an ultraviolet (UV) radiation-induced immunologic alteration. Exposing Skh-1 hairless mice to a regimen of nonerythemal UV-B (290-320 nm) radiation induced skin wrinkles after 6-7 weeks. Concomitant treatment with cyclosporin A decreased the time to the onset of wrinkles to approximately 4 weeks. Exposing HRS/J hairless mice or athymic nude mice to a similar nonerythemal UV-B radiation regimen for 10 weeks failed to induce skin wrinkles. Concomitant administration of cyclosporin A and UV-B radiation for 7 weeks to HRS/J hairless mice induced no skin wrinkles. Ultraviolet-B or UV-B plus cyclosporin A exposure caused increased immunohistochemical staining for Ia and F4/80 antigens in the upper dermis of tissue from Skh-1 mice, as compared to controls. Treating Skh-1 mice with UV-B radiation plus cyclosporin A was also associated with a large increase in the number of CD3+ cells in the dermis. These staining patterns were absent in similarly treated HRS/J hairless mice. Dermal mast cell numbers in Skh-1 mice were 2-3-fold higher than in HRS/J, athymic nude or NSA mice. Treatment with cyclosporin A increased Skh-1 dermal mast cell numbers approximately 2-fold but had no effect on the dermal mast cell numbers in HRS/J or NSA mice. Based on these findings we postulate that UV-B light and cyclosporin A exacerbate an immunological condition in Skh-1 mice, one consequence of which is manifested as skin wrinkles. Thus, the induction of skin wrinkles in this mouse strain may have no relevance to the wrinkles observed in human skin after chronic exposure to sunlight.     

IRREVERSIBLE PHOTOBINDING TO SKIN CONSTITUENTS AFTER SYSTEMIC ADMINISTRATION OF CHLORPROMAZINE TO WISTAR RATS

From in vitro experiments it is known that chlorpromazine binds to protein and DNA/ RNA upon UV-irradiation. In the present study the possible photobinding of chlorpromazine (or its metabolites) in vivo was examined. Tritium labeled drug was administered intraperitoneally to female albino Wistar rats after which they were irradiated with light with maximum intensity at 310, 370 or 420 nm. After homogenization, unbound radioactivity in tissue of several organs was removed by dialysis. In the ears, eyes and skin of the back irreversibly bound radioactivity could be detected after irradiation with 310- and 370- but not with 420 nm light. Binding in the skin of the back after UVA irradiation was examined in more detail by separating epidermal lipids, DNA/RNA and proteins by a selective extraction/precipitation method. Radioactivity appeared to be bound to lipids and proteins but not to DNA/RNA.     

EFFECTS OF UV IRRADIATION ON A LIVING SKIN EQUIVALENT

Abstract— The Living Skin Equivalent (LSE™) is an organotypic coculture composed of human dermal fibroblasts interspersed in a collagen-containing matrix and overlaid with human keratinocytes forming a stratified epidermis. The LSE has a dry, air-exposed epidermal surface suitable for the application of oils, creams and emulsions. These features suggested its feasibility as an in vitro skin model for studying the protective effects of sunscreens. Using the thiazolyl blue (MTT) conversion assay as a measure of mitochondrial function, the extent of cytotoxicity induced by various doses of UV-R (280–400 nm) or UV-A (320–400 nm) was evaluated in the LSE. The doses of UV radiation that caused 50% reductions in MTT conversion (UV-R₅₀ or UV-A₅₀) in different lots of LSE were 0.053 ± 0.021 J/cm² (n = 29) and 11.6 ± 4.9 J/cm² (n = 17) for UV-R and UV-A, respectively. The protective effects of an 8% homosylate standard and of five UV-A sunscreens, topically applied to the LSE, were determined and compared with their reported protection factors in human skin. Morphological changes and the release of proinflammatory mediators (interleukin-1-α, tumor necrosis factor-α and prostaglandin E2) implicated in UV-induced erythema were also demonstrated in the LSE exposed to UV-A or UV-B. The data suggest that the LSE can be used for studying the effects of U V radiation on skin and may have utility for assessing the efficacy of certain sunscreens against UV-B and UV-A.     

标准物质基体对马拉硫磷气相色谱响应的影响

对马拉硫磷在甲醇、丙酮、乙酸乙酯、二氯甲烷4种溶剂中的气相色谱峰单位浓度面积响应进行了研究,用t检验法判定响应差异性.研究结果证明,浓度相同但溶剂不同的马拉硫磷溶液,在其它实验条件均相同的情况下,气相色谱峰单位浓度面积响应有显著性差异;用前处理后待测样浓缩液的基体稀释对照样,可以减小或消除马拉硫磷标准物质基体与方法中要求的标准储备液基体的差异性所带来的对待测样检测结果的影响.     

FUNCTIONS OF LIPIDS ON HUMAN SKIN

In order to clarify the roles of lipids in the water-holding property of stratum corneum, the forearm skin of healthy male volunteers was treated with acetone/ether (1/1) or sodium dodecyl sulfate (5%) for 1-30 min. A prolonged treatment period of 5-30 min produced a chapped and scaly appearance of the stratum corneum without any inflammatory reactions. Under these conditions, there was a marked decrease in the water-holding capacity of the stratum corneum accompanied by a selective loss of stratum corneum lipids such as cholesterol, cholesterol esters, and sphingolipids. Two daily applications of the isolated stratum corneum lipids to experimentally induced dry skins caused a significant increase of conductance, accompanied by a marked improvement in the level of scaling. Meanwhile, the isolated sebaceous lipids exhibited no significant recovery in both the conductance value and the scaling. Out of chroma-tographically separated fractions of the stratum corneum lipids, topical applications of ceramide fraction induced the highest increase in the conductance value. Topical applications of synthesized pseudo-ceramides also showed a significant recovery of the water-retaining properties accompanied by an improvement in the scaling only when the polar group has an amide bond in the major linkage. Analysis of the alkyl chain structures has revealed that a structural requirement for the recovery of the water retaining capacity is the presence of saturated-straight alkyl chains, not unsaturated or branched alkyl chains. These structural characteristics required for water-retaining function also paralleled their capacity to form multiconcentric lamellae vesicles in vitro which is also capable of acquiring bound water as shown by DSC thermograms. The present study suggests that ceramides with relatively shorter alkyl chain length serve as a water modulator in the multi-lipid bilayers through the stratum corneum.     

INHIBITION OF 12-O-TETRADECANOYLPHORBOL-13-ACETATE-INDUCED TUMOR PROMOTION IN MURINE SKIN BY SYSTEMIC EFFECTS OF ULTRAVIOLET IRRADIATION

Systemic effects of UVB irradiation (280-320 nm) have been shown to prevent subsequent chemical tumorigenesis induced by an initiation-promotion protocol. The present investigation was designed to determine whether initiation or promotion is prevented by UV irradiation. Groups of 25 B6D2F1/J mice received 12 weeks of intermittent dorsal UVB radiation treatments administered before, or 3 weeks after, initiation with a single application of 7,12-dimethylbenz[a]anthracene on the ventral skin. All mice were promoted ventrally with 5 micrograms 12-O-tetradecanoylphorbol-13-acetate (TPA) applied three times weekly throughout the experiment. UV irradiation consisted of five 30-min exposures per week to a bank of 6 Westinghouse FS40 sunlamps. UV irradiation applied before or after initiation resulted in a decrease of 18-16 tumors per group of 25 mice, for a reduction of 61 and 50%, respectively, at 24 weeks after the first TPA treatment. Thus, prevention of tumor development was similar whether the UV influence was present or not during initiation. This finding suggests that the UV prevention of promotion could account for UV inhibition of skin tumors induced by an initiation-promotion regimen. Consistent with this concept, pretreatment of mice with dorsal UVB radiation was found to reduce DNA synthesis after exposure to TPA by 46%, although it did not decrease tritiated benzo[a]pyrene binding to DNA, in ventral epidermis. Thus, UVB irradiation systemically reduced TPA-induced tumor promotion in murine skin.     

预辐照接枝丙烯酸、苯乙烯磺酸钠对聚全氟乙丙烯膜性能的影响

采用常温下γ射线预辐照引发接枝的方法,在聚全氟乙丙烯(FEP)上接枝了丙烯酸(AA)和对苯乙烯磺酸钠(SSS),制备了一种含羧酸基团和磺酸基团的接枝膜.傅立叶变换红外光谱(FT-IR)分析证明了磺酸基团和羧酸基团的成功引入.采用XRD、TGA和接触角研究了接枝率对FEP膜的结晶度、热学特性及亲水性等性能的影响.结果表明,随着制备的FEP膜接枝率的增加,膜的结晶度、热稳定性和接触角逐渐减小;与此相反,FEP膜的亲水性能随接枝率的增加而增加.接枝膜湿敏性能测定结果表明,在相对湿度从5%RH变化到98%RH时,接枝膜电阻线性变化范围接近3个数量级,具有响应速度快(吸附<1min,解吸<2min),湿滞小(<3%RH)的特点,具有应用于电阻型湿度传感器的广阔前景.     

硫醇化合物在银盐CTP版材上的疏水作用

本文采用线形CCD(ChargeCoupledDevice)技术、接触角等方法研究了一种长链硫醇化合物对计算机直接制版材料物理显影动力学及疏水性能的影响。结果表明,该化合物是物理显影过程的抑制剂,在显定合一的加工液中添加该化合物可以显著提高版材物理显影银区的疏水性能。同时,通过表面显微拉曼光谱进一步证明了硫醇化合物在物理显影银表面的吸附增加了版材的亲油性。     

固定床吸附的动力学模型及吸附剂形状因子的影响

本文的固定床吸附模型以固体表面扩散为基础。同时考虑吸附剂颗粒内外扩散阻力轴向弥散，非线性吸附平衡和吸附剂形状因子的影响。详细讨论了吸附剂形状因子对固定床吸附动力学的影响。当三种形状吸附剂颗粒的特征尺寸相同时，透过时间大小顺序为：球形〉无限长圆柱形〉无限薄片形；在某些特定条件下，吸附剂形状因子对透过时间及穿透曲线的影响可以忽略。     

在样模制备法中影响有序金属Ni纳米线尺寸的因素

以多孔氧化铝为样模,运用电沉积法向样模的微孔中沉积金属Ni,制备得到了有序排列的金属Ni纳米线阵列;以透射电镜为主要表征手段,系统地研究了多孔氧化铝样模的制备条件对金属Ni纳米线尺寸的影响;结果表明：制备多孔氧化铝样模过程中的氧化介质、氧化温度、氧化电压以及氧化后的扩孔时间影响Ni纳米线的直径和长度,而电沉金属镍时的沉积电压和沉积时间则主要影响纳米线的长度。     

催化剂对煤粉燃烧特性的影响

在燃烧试验台上考察了不同类型催化剂对烟煤、无烟煤的催化燃烧作用。燃烧率测定、扫描电镜观察和Ｘ射线衍射分析，Ｆｅ＾３＋、Ｆｅ＾２＋、Ｃａ＾２＋及其与ＣａＣＯ３的混合物有效强的催化作用，且对无烟煤更显著。其中ＣａＣＯ３－Ｍ（Ｆｅ、Ｃａ）二元催化剂更适于工业应用，其最佳加入量为５￣７Ｗ％左右。     

聚合物分子链的横截面积与分子链的运动

本文把单个分子链的横截面积与聚合物的玻璃化转变温度联系起来,发现对于所讨论的聚合物,考虑了分子链间的相互作用以后,上面二者之间有一一对应的关系。认为单个分子链的横截面积与聚合物分子链柔顺性有关。同时采用文献[17]的方法,得到了1,2-聚丁二烯的分子链的内旋转异构化能,比较所得结果,证实了上面的看法。     

INFLUENCE OF FLUOROCARBON EMULSIONS ON PORPHYRIN-SENSITISED OXIDATION OF HISTIDINE

The influence of fluorocarbon emulsions on the efficiency of photosensitized oxidation of histidine in solution has been studied, using haematoporphyrin and dihaematoporphyrin derivatives as sensitisers. It is shown that the fluorocarbon emulsions at low concentrations efficiently disaggregate porphyrins, and thereby enhance photosensitised oxidation. The high solubility of oxygen in fluorocarbon emulsions maintains solution oxygen tension, optimising photooxidative damage. It is suggested that fluorocarbon emulsions might find a role in photodynamic therapy, both as carriers for sensitising dyes, and also to maintain tissue oxygenation in hypoxic regions of solid tumours.     

取代基对螺吡喃感光剂性质的影响

吲哚啉螺苯并吡喃类化合物作为有机感光剂在光信息储存方面有很大的实用价值。本文用2,3,9,9a-四氢-9,9,9a-三甲基噁唑并[3,2a]吲哚(简称TTOI)与水杨醛及其衍生物在无水乙醇中合成了17个化合物。     

INFLUENCE OF PLASMA DENSITY ON NUCLEATED DENSITY OF DIAMOND

The predeposition method for mereasing CH_4 concentration ininitial stage of diamond synthesis by plasma chemical vapor deposition.isused to enhance nucleated density of diamond films.The plasma parametersare diagnosed in situ using the Langmuir double probe.The relation betweenplasma ion density and nucleated densitv of diamond is revealed Increasingplasma ion density results in enhancement of nucleated density of diamondobviously     

二次炭化对PAN-ACF结构和性能的影响

ＰＡＮ－ＡＣＦ经二次炭化后,孔径结构及表面微结构均发生了很大的变化。本文讨论了在两个具有代表性的二次炭化温度下,ＡＣＦ的孔径结构以及表面微结构（表面性质）的变化。并初步讨论了结构变化机理。