The temperature dependence of derivative ultraviolet absorption spectra

The effects of variation of temperature in the range 0 degrees -40 degrees C on the zero and second derivative ultraviolet absorption spectra of ten compounds have been investigated. When the temperature of the solutions was increased, most of the substances showed a linear reduction of maximum absorbance (A(max)), with temperature coefficients of -0.07 +/- 0.03% per degree. The second derivative amplitudes of all the substances were reduced, with temperature coefficients (-0.1 to -0.5% per degree) that bore no significant relationship to those of the corresponding A(max) values. These effects on the extrema of the derivative spectra are explained by the small reduction in curvature at the corresponding wavelengths of the fundamental spectra, that occurs with increasing temperature. The precise and accurate assay of substances by derivative UV spectrophotometry requires that the temperatures of the standard and sample solutions are identical at the time of measurement.     

紫外线对角膜内抗氧化酶mRNA表达的影响

为了进一步从基因水平探讨紫外线的损伤机制,我们采用ＲＴ－ＰＣＲ方法,用紫外线照射大鼠角膜,检测大鼠角膜内三种抗氧化酶;谷胱甘肽过氧化物酶,铜锌－超氧化物歧化酶,过氧化氢酶ｍＲＮＡ的表达。结果显示,照射早期,三种抗氧化酶ｍＲＮＡ表达均升高,ＧＳＨ－Ｐｘ和ＳＯＤ的表达高点为照射５ｍｉｎ,ＣＡＴ的表达高点为照射２ｍｉｎ照射晚期,照射１５ｍｉｎ,三种酶的ｍＲＮＡ表达明显下降,照射后４８ｈ,三种抗氧化酶的表     

维生素C在晶体蛋白光氧化中的作用及其机制

目的：观察维生素Ｃ（ＡＳＡ）在晶体蛋白发生光氧化时的作用及其机制。方法：牛日体蛋白溶液在加入或不加入ＡＳＡ时,于５天内共接受２００ｍＪ／ｃｍ＾２紫外线Ｂ（ＵＶＢ）照射,接着在３７℃继续孵育至第３周,然后测定晶体蛋白的非色氨酸我、游离巯基和进行蛋白电泳分析。结果：ＡＳＡ在溶液中易被氧化,蛋白溶液中加入ＡＳＡ促使晶体蛋白 非色氨酸荧光产生明显增强,导致非二硫键聚合形成,对晶体蛋白的游离巯基减少有保护作     

Release of intracellular enzymes from cutaneous cells after non-necrotizing damage by ultraviolet light

Summary Experimental blisters were produced with suction on normal human skin and simultaneously on skin inflamed after exposure to middle wave ultraviolet light. Total proteins and marker enzymes for the plasma membrane, cytosol, lysosomes, peroxisomes, mitochondria, and microsomes were assayed in the blister fluid. In blisters on erythematous skin, a large increase of lactate dehydrogenase from cytosol was noted. A small increase of the plasma membrane marker phosphodiesterase I and some increase of -mannosidase from lysosomes was also found. No significant increase in total proteins or in the markers for peroxisomes was observed, whereas mitochondrial and microsomal marker enzymes were not detectable.It is concluded that cutaneous cells to some extent may lose intracellular enzymes without visible signs of irreversible damage (necrosis), but that an UVB-induced injury/regeneration cycle probably explains the enzyme release.     

紫外分光光度法测定土霉素片的含量

目的：应用紫外分光光度法测定土霉素片的含量。方法：用0．01mol／LHCL溶液作溶剂。紫外检测波长271nm。结果：通过实验方法考察，样品浓度每4ml～32土霉素单位范围内呈良好的线性关系。回收率为100．1％(n=8)。结论：方法简便、快速、结果稳定。     

复方利福平片溶出度测定方法的研究

目的 建立复方利福平片的溶出度测定方法。方法 采用溶出度测定法第二法，以水为溶剂，转速为50r／min，经45min取样，紫外分光光度法在474nm处测定利福平的溶出量，溶出限度为标示量的75％。结果利福平在10．3—36．1μg／ml范围内线性关系良好(r＝1．0000)，平均回收率99．8％。结论 本方法准确、快速、简便。通过测定复方利福平片的溶出度可有效检测其制剂工艺水平。     

紫外分光光度法测定吉非罗齐含量

目的建立用紫外分光光度法到定吉非罗齐的含量；方法以乙醇为溶剂，采用分光光度法，在276nm到定吉非罗齐含量；结果 吉非罗齐在0—219．2μg／m1范围内，其吸收度呈良好的线性，R＝0．9999，平均回收率100．1％，RSD为0．36％。结论 本法简便快速，结果与药典法基本一致。     

紫外分光光度法测定呋麻滴鼻液中盐酸麻黄碱的含量

目的建立呋麻滴鼻液中盐酸麻黄碱的紫外分光光度法的含量测定方法。方法次氯酸钠为氧化剂，测定由盐酸麻黄碱被次氯酸钠氧化后的氧化产物苯甲醛，检测波长为249nm。结果盐酸麻黄碱在2～18μg/ml范围内，线性关系良好(r=0．9996)，平均回收率为98．05％(n=9，RSD=0．72％)。结论本法灵敏度高，快捷准确。     

紫外线诱导体外培养的LOVO、HT-29细胞的凋亡

目的研究紫外线照射体外培养的大肠癌ＬＯＶＯ和ＨＴ┐２９细胞后，诱导这两株大肠癌细胞系发生凋亡的作用。方法紫外线照射两株大肠癌细胞系后２４～３６ｈ，通过琼脂糖凝胶电泳、ＨＥ染色和流式细胞仪检测两株细胞发生凋亡的情况。结果两株大肠癌细胞在形态学上出现典型的细胞核固缩、碎裂，琼脂糖凝胶电泳显现特征性的“梯状”带，流式细胞仪分别在２４和３６ｈ出现亚二倍体峰。结论紫外线具有杀灭癌细胞的作用，其机制与诱导细胞凋亡有关；其方法简单、易行，可作为研究细胞凋亡的较好的体外模型。     

紫外线量子照血法治疗突聋的疗效观察

采用紫外线量子辐照血液疗法(Ultraviolet blood Irradiation,UBI)加综合药物治疗突聋25例,并与单纯的综合药物治疗进行疗效比较.UBI组耳聋的有效率为75.86%,对照组为55.55%;对耳鸣的疗效,前者为82.60%,后者为54.54%,两者皆有显著性差异.认为UBI对突聋确有明显的治疗作用,对耳鸣的疗效更为显著.