DETERMINATION OF CYTOSINE-CYTOSINE PHOTODIMERS IN THE DNA OF CLOUDMAN S91 MELANOMA CELLS USING HIGH PRESSURE LIQUID CHROMATOGRAPHY

Abstract
I measured the induction of cytosine-cytosine dimer (C-C) densities after UV-C (< 290 nm) and UV-B irradiation (290–320 nm) in the 2'-deoxy-[³H]cytidine labeled DNA of Cloudman S91 mouse melanoma cells using a new, sensitive high pressure liquid chromatography procedure. UV-B exposure resulted in 0.000034% C-C/J m^-2 of the total cytosine radioactivity which is 10 times less than the rate during UV-C irradiation. Previous work with these melanoma cells showed a 4-fold lower rate of induction of thymine-containing pyrimidine dimers by UV-B than UV-C light (Niggli Photochem. Photobiol . 52 , 519–524, 1990). Based on these results, the calculated ratios for the pyrimidine dimer subspecies showed no significant difference following UV-C and UV-B exposure. However, UV-C and UV-B light induce 10–20 times more thymine-containing pyrimidine dimers than C-C in the DNA of S91 cells.     

高效液相色谱法测定几种野生植物中的β—胡萝卜素

用高效液相色谱法,采用紫外检测器,于436nm处测定了虫草、香橼、火棘果、滇刺枣中β-胡萝卜素的含量。在0.00492～0.0492mg/mL浓度范围内,线性关系好(r=0.999,n=5)。回收率92.3％～106.8％。     

COMPARATIVE STUDIES ON THE CORRELATION BETWEEN PYRIMIDINE DIMER FORMATION and TYROSINASE ACTIVITY IN CLOUDMAN S91 MELANOMA CELLS AFTER ULTRAVIOLET-IRRADIATION

We compared the induction of pyrimidine dimer densities after UV-irradiation in mouse melanoma cells before and after treatment with cholera toxin. Treatment with cholera toxin stimulated tyrosinase activity up to 50-fold, leading to a marked, visually apparent increase in cellular melanin concentrations. Irradiation of treated and untreated cells was therefore designed to establish whether intracellular melanin protected cells from UV-induced DNA damage. In experiments described here, we determined cytosine-thymine (C-T) as well as thymine-thymine dimer levels (T-T) by high pressure liquid chromatography in cholera toxin-treated and untreated Cloudman S91 mouse melanoma cells after irradiation with UVC (less than 290 nm) and UVB light (290-320 nm). Surprisingly, induction of melanization had no effect on the formation of pyrimidine dimers by UVC or UVB irradiation. These results indicate that de novo melanin pigmentation induced via the c-AMP pathway is not involved in protection against UV-induced thymine-containing pyrimidine dimers. In separate experiments, irradiation of toxin-treated and untreated mouse melanoma cells with UVC or UVB light produced a 20-30% lower dimer density compared to irradiated human skin fibroblasts. This finding suggests that melanin has some protection properties against UV-induced pyrimidine dimers, although the exact defense mechanism seems highly complex.     

高效液相色谱法测定血浆中的司帕沙星

用高效液相色谱法测定血浆中司帕沙星的浓度。以氧氟沙星为内标物,选择ZORBAXSB-C18色谱柱,以甲醇-磷酸盐溶液(35∶65)为流动相,血浆样品经乙腈沉淀蛋白质后高速冷冻离心,取上清液经0.22μm滤膜过滤后进样,检测波长为298nm。司帕沙星色谱保留时间为9.986min。在0.03124.00mg/L范围内线性关系良好(r=0.9998),回收率为93.95?.30%,日内RSD为1.21%2.69%,日间RSD为1.44%2.95%,最低检出限为5μg/L。该方法可用于药物动力学研究和临床药物监测。     

高效液相色谱法测定苁蓉酒中松果菊苷的含量

建立反相高效液相色谱法测定苁蓉酒中松果菊苷含量。固定相为C18,流动相为甲醇-0．1％甲酸水溶液（体积比为33：67）,流速1．0mL／min,柱温为30℃,检测波长为330nm。松果菊苷的浓度x（mg／mL）与其峰高y呈良好的线性关系,线性方程为Y=2．5955x,相关系数为0．9999。样品的加标回收率为88．1％～107．5％,测定结果相对标准偏差为0．41％（n=5）。     

高效液相色谱法测定氧氟沙星胶囊中氧氟沙星的含量

建立测定氧氟沙星胶囊中氧氟沙星含量的高效液相色谱法。选用AgilentEclipseXDBC8柱(250mm×4.6mmi.d.,5μm)及LabAllianceC8保护柱(10mm×4.6mmi.d.,5μm),流动相为乙腈-水(体积比为25∶75,含20.0mmol/L磷酸二氢钾及0.2%三乙胺,用0.2%磷酸溶液调至pH=5.50),流动相流速为1.0mL/min,检测波长为293nm,进样量为20μL,外标法定量。测定氧氟沙星胶囊中氧氟沙星含量的线性范围为1.00～200μg/mL(r=0.9998),回收率为98.8%～100.7%,测定结果的相对标准偏差为0.75%～1.17%(n=5)。     

高效液相色谱法测定食品中的富马酸二甲酯

采用高效液相色谱法测定食品中的富马酸二甲酯.样品中的富马酸二甲酯经甲醇提取后,以甲醇-乙酸铵溶液(体积比为55∶45)为流动相,C18色谱柱分离,二极管阵列检测器检测,检测波长为210 nm,外标法定量.方法的线性范围为1～16μg/mL(r=0.99987),检出限为0.1μg/g,测定结果的相对标准偏差为0.54%...     

高效液相色谱法测定浓缩苹果汁中的多菌灵残留量

建立了测定浓缩苹果汁中多菌灵残留量的高效液相色谱法。色谱柱为ZOBAX Extend-C_(18)柱(150mm×4.6mmi.d., 5μm),流动相为甲醇-水(体积比为60:40),流速为1.0mL、min,检测波长为285nm。多菌灵的浓度在0.05～5.00mg/L范围内与峰面积之间具有良好的线性关系,线性回归方程为A=185162c 3432.2,相关系数r=0.9998,回收率为91.8％～104.2％,相对标准偏差为7.59％～8.78％,检出限为1.0μg/L。方法简便、快速、灵敏,可满足农药残留的检测要求。     

COMPARATIVE ACTION SPECTRA FOR PYRIMIDINE DIMER FORMATION IN CLOUDMAN S91 MOUSE MELANOMA and EMT6 MOUSE MAMMARY CARCINOMA CELLS

Abstract— Pyrimidine dimer formation in melanotic mouse melanoma cells, Cloudman S91H-. and iii mouse mammary carcinoma cells, EMT6, was compared as a function of wavelength by irradiating equal numbers of cells from the two cell lines simultaneously. More dimers were formed in EMT6 than in S91H– by light of wavelengths less than 289 nm, while light of higher wavelengths caused equivalent dimer formation, as measured by the Micrococcus luteus UV-endonuclease assay. The cells of S91 flare lightly melanotic, yet shielding at lower wavelengths is considerable. It is speculated that melanin pigmentation arose by selection during an evolutionary period when UV-C light reaching the earth's surface was significantly greater than it is today.     

高效液相色谱法测定箭叶淫羊藿中淫羊藿苷的含量

箭叶淫羊藿用70%乙醇回流提取,取部分提取液直接干燥得淫羊藿提取物,以高效液相色谱法测定箭叶淫羊藿中淫羊藿苷的含量,色谱柱为InertsilODS-3柱,流动相为乙腈-水(27∶73),检测波长为270nm。在此条件下,淫羊藿苷与其它黄酮醇苷的色谱峰分离完全,平均回收率为99.46%。该法可用于淫羊藿药材的质量控制。     

高效液相色谱法测定巧克力中的可可碱和咖啡因

使用Zobarx Eclipse XDB C18柱,以水-乙脯(体积比为88：12)为流动相,选择测定波长为278nm,应用高效液相色谱法测定巧克力中的可可碱和咖啡因。可可碱和咖啡因的平均回收率分别为96．7％和97．4％．RSD分别为1．05％和2．16％(n=5),检出限均为0．005g／kg。     

高效液相色谱法测定化妆品中去屑剂的不确定度评定

根据JJF1059—1999,评定化妆品中水杨酸、吡硫翁锌、酮康唑、甘宝素和吡罗克酮乙醇胺盐5种去屑剂高效液相色谱法测定结果的不确定度。水杨酸、吡硫翁锌、酮康唑、甘宝素和吡罗克酮乙醇胺盐5种去屑剂测定结果的相对扩展不确定度分别为3．8％、5．4％、3．0％、3．2％和5．0％。     

高效液相色谱法测定DNTF纯度

采用Agilent HC-C18色谱柱,以乙腈-水(体积比为60∶40)为流动相,在流速1.0mL/min,检测波长216nm,柱温为室温的条件下进行3,4-二硝基呋咱基氧化呋咱(DNTF)的纯度测定。DNTF与可能的副产物的色谱峰有很好的分离,DNTF浓度(c)在0.00346～0.692mg/mL范围内与色谱峰面积(A)与呈线性关系,线性方程为A=73440c+1030.3,相关系数r=0.9988。采用外标法单点校正峰面积定量,对DNTF标准溶液测定的回收率为98.41%～100.43%。用该法测定了不同合成路线及精制阶段的DNTF纯度。     

高效液相色谱法测定火腿肠中的诱惑红

火腿肠经脱脂后,用乙醇-氨-水溶液提取色素,溶液经浓缩后,在酸性条件下用聚酰胺吸附,在碱性条件下解吸附,定容制成水溶液。以C18柱分离,用二极管阵列检测器检测,采用反相高效液相色谱法测定火腿肠中的食用合成色素诱惑红,回收率为85、8％～93．7％,测定结果的相对标准偏差为1．25％～2．39％,线性范围为1～100mg／L,检出限为0．5mg／kg。     

高效液相色谱法测定食品中的酸性橙Ⅱ

建立测定食品中酸性橙Ⅱ?B5母咝б合嗌追椒āＲ约状?水为提取溶剂，采用超声波对样品进行处理。采用ODS柱分离，以甲醇和0.02mol／L乙酸铵溶液进行梯度洗脱，在484nm波长下检测。酸性橙Ⅱ?B5闹柿颗ǘ仍?，003—1．000g／L范围内与其色谱峰面积的线性关系良好(r=0，9998)，加标回收率为99％-106％，RSD为3．1％。     

高效液相色谱法测定果珍中维生素C含量

用0.1％的草酸作为流动相,高效液相色谱法测定了果珍中维生素C的含量。维生素C的浓度c在0-300μg／mL范围内与色谱峰面积A呈正比关系,线性相关系数为0.9993。方法的回收率为96．2％-103．2％,测定结果的相对标准偏差为0．6％（n=8）。利用高效液相色谱法测定果珍中的维生素c的含量,具有试剂用量少、操作简单、结果准确等特点,采用弱酸性的草酸为流动相,避免了维生素c的分解。     

高效液相色谱法测定金葱粉中的罗丹明B含量

建立了金葱粉中罗丹明B的提取、富集净化和测定的方法.样品经加热萃取、聚酰胺吸附罗丹明B、碱液解吸、蒸发、定容,用高效液相色谱-紫外检测器进行测定.测定条件:色谱柱为ODS C18;流动相为甲醇-水(体积比为70∶30);流速为1.5 mL/min;检测波长为550 nm.罗丹明B在0.14～22 μg/mL浓度范围内与...     

高效液相色谱法测定动物组织中8种磺胺类药物残留量

提出了一种快速、准确地同时测定动物组织中磺胺类药物残留量的检测方法。样品中加入无水硫酸钠后,用乙腈均质、提取,在离心后的沉淀物中加入乙腈,再次提取,合并乙腈提取液。提取液用乙腈饱和正己烷溶液净化,去除脂肪和杂质,用高效液相色谱方法进行测定。通过优化色谱条件,利用紫外检测器(VWD)或二极管阵列检测器(DAD)对8种磺胺类药物残留进行同时测定,测定结果的相对标准偏差为5.1％～12.8％,平均回收率为62.7％～105．1％,检出限为10μg/kg。