Effects of Clodronate on Cortical and Trabecular Bone in Ovariectomized Rats on a Low Calcium Diet

The aim of this study was to evaluate the contribution of a low calcium diet to the cortical and trabecular osteoporosis seen in ovariectomized rats after 7 weeks on a low calcium diet and to investigate the effects of the bisphosphonate clodronate on this development of osteoporosis. Thirty-six mature, female Wistar rats were randomized into four groups: Ovx−B (bisphosphonate) and Ovx−C (control) were ovariectomized, and Sham−Ca (low calcium) and Sham+Ca (normal calcium) were sham operated. The first three groups were fed a low calcium diet (0.01%) and Sham+Ca normal rat chow (Ca 1.1%). The Ovx−B received 10 mg/kg s.c. clodronate daily for nine weeks, and Ovx−C, Sham−Ca, and Sham+Ca received the same volumes of saline. Bone mineral turnover measured as ⁸⁵Sr-uptake was increased in all low calcium groups compared to Sham+Ca. The Sham+Ca femora had higher dry weight and ash weight than the other groups, and Ovx−C had higher dry weight compared with Ovx−B and Sham−Ca. Calcium content was lower in both Ovx groups compared to both Sham groups. Magnesium was lower in all groups compared to Sham+Ca and higher in Ovx−B compared with Ovx−C. In the femoral shaft, Sham+Ca had significantly higher ultimate bending moment, energy absorption, and deflection compared to the other three groups. Ultimate bending moment was higher in Sham−Ca than in Ovx−C. Stiffness was increased in both Sham+Ca and Ovx−B compared to Ovx−C. The maximum stress in the femoral midshaft was higher in Sham+Ca than in the other groups, and higher in Ovx−B than in Ovx−C. Histomorphometry showed increased medullary area in all low calcium groups compared to Sham+Ca and larger cortical area in Sham+Ca and Ovx−B compared to Ovx−C. Compared to Sham+Ca the trabecular bone volume was decreased to 30% in Sham−Ca and to 9% in Ovx−C, but was unchanged in Ovx−B. The low calcium diet generally increased bone mineral turnover and reduced the tibial bone volume. Femoral changes led to a reduction of cortical fracture strength and maximal stress. Ovariectomy in addition to a low calcium diet reduced femoral strength even more. Daily injections of clodronate to ovariectomized rats on a low calcium diet increased femoral shaft stiffness and maximum stress, and clodronate preserved both trabecular and cortical tibial bone volume completely. Received: 11 June 1996 / Accepted: 5 March 1997     

工业X射线探伤防护剂量水平的研究

本文介绍了用实验方法研究不同管电压, 钢板厚度与散射线之间的关系.结果表明, 透射比随管电压升高而增加, 并随钢板厚度增加而下降；散射比随散射角的增大而逐渐下降, 至180°时为最低值。此研究为X射线探伤作业的辐射防护提供了依据。     

延边地区警察人群血脂水平

目的了解延边地区警察人群的血脂水平。方法将382例（男350例，女32例；朝鲜族165例，汉族217例）延边少数民族自治州公安局职工作为观察组，将100例健康人群作为对照组，应用日立7600生化分析仪分别测定甘油三酯（TG）、总胆固醇（CHO）、高密度脂蛋白胆固醇（HDL—C）、低密度脂蛋白胆固醇（LDL—C），并进行对比分析。结果观察组检出血脂异常者220例，占58．9％；对照组28例，占28％，两者差异有统计学意义（Х^2=27．78，P〈0．01），观察组明显高于对照组。此外，观察组中朝鲜族与汉族的血脂异常率差异无统计学意义（P〉0．05），但男女差异显著（P〈0．01）。结论延边地区警察人群的血脂代谢异常率明显高于普通人群，无民族差异，提示该人群应及早加强健康教育和其他预防措施。     

Loading anticancer drugs into HDL as well as LDL has little affect on properties of complexes and enhances cytotoxicity to human carcinoma cells

Low density lipoprotein (LDL) has been found to represent a suitable carrier for cytotoxic drugs that may target them to cancer. This study investigated whether very low density lipoprotein (VLDL), LDL and high density lipoprotein (HDL) can be used to effectively incorporate four cytotoxic drugs, 5-fluorouracil (5-FU), 5-iododeoxyuridine (IUdR), doxorubicin (Dox) and vindesine; characterized the complexes; and examined the effect of incorporation on drug cytotoxicity against HeLa cervical and MCF-7 breast carcinoma cells. Significant drug loading was achieved into all three classes of lipoproteins, consistent with the sizes and hydrophobicity of the drugs. The relative loading efficiency was found to be vindesine>IUdR>Dox>5-FU for all three classes of lipoproteins. As shown by electron microscopy (EM), drug incorporation did not affect the size or morphology of the lipoproteins. Differential scanning calorimetry (DSC) showed that drug loading did not significantly change the thermal transition temperature of core lipids in the lipoproteins. The transition enthalpy was changed only for LDL–Dox and LDL–vindesine. The drugs remained stable in the lipoproteins as determined by high performance liquid chromatography (HPLC). EM, DSC and HPLC data suggest that drugs were incorporated into lipoproteins without disrupting their integrity and drugs remained in their stable forms inside lipoproteins. Compared with free drugs in cytotoxicity assays, the IC₅₀ values of LDL– and HDL–drug complexes were significantly lower (2.4- to 8.6-fold for LDL complexes and 2.5- to 23-fold for HDL complexes). All free or lipoprotein-bound drug formulations were comparably more cytotoxic against MCF-7 than HeLa cells. Upregulating the lipoprotein receptors enhanced, and downregulating them inhibited, the cytotoxicity, indicating the mechanistic involvement of lipoprotein receptor pathways. Complexes of all four drugs with VLDL, in contrast to LDL and HDL, had the same cytotoxicity as the four corresponding free drugs. Our results suggest that further studies are required of the potential of HDL to be a cancer targeting drug carrier.     

应用荧光探针H2DCF-DA检测光照致细胞内活性氧产生的初步研究

目的应用荧光显微镜及新型荧光探针H2DCF-DA检测在光源照射过程中人脐静脉血管内皮细胞(ECV304)内活性氧的产生情况。方法将ECV304细胞接种于35mm培养皿中,24h后加入H2DCF-DA,使其终浓度为10μmol/L,孵育30min。利用荧光显微镜的激发光源作为照射光源,在采集荧光图像的同时完成光源照射,光源输出波长范围为460～490nm,功率密度约为100mW/cm2。连续采集DCF的荧光图,观察细胞内DCF荧光的变化情况,采用计算机图像处理和分析技术,求得细胞内不同照射时间点DCF平均荧光强度,进而得到平均荧光强度-时间曲线。另外,使用线粒体特异标记探针MitoFluorRed589与H2DCF-DA共同孵育细胞,分别采集同一细胞的DCF的荧光图和MitoFluorRed589的荧光图,并利用像素-荧光强度分析方法来确定DCF荧光在细胞内的分布位置。结果在光源照射的开始阶段,ECV304细胞内的DCF荧光强度迅速增加,在第10s时便上升至第2s时的2.2倍,但是随着照射时间逐渐延长,荧光强度增幅逐渐变小,到第60s时上升至第2s时的4.7倍。观察时间进一步延长,DCF的荧光强度的变化似乎进入平台期,继而开始出现下降。考察DCF荧光在ECV304细胞内的分布位置主要通过比较细胞内不同区域的I1/I2值,通过图像分析与计算得到线粒体区、细胞核区以及细胞质非线粒体区内I1/I2值分     

防晒制剂皮肤安全性的实验研究

目的 :探讨同一系列不同SPF(sunprotectionfactor)防晒制剂对皮肤的安全性 ,筛选安全有效的防晒制剂配方。方法 :选用白化豚鼠背部去毛 ,分别涂抹SPF值为 15、2 8、30 +三种防晒制剂 ,以UV光源照射 ,波长为 32 0～4 0 0nm ,强度为 ( 16 8± 2 )mW/cm2 。结果 :三种不同SPF防晒制品对实验动物皮肤各时相点反应积分为 ,SPF15组为0 ;SPF2 8组为 1;SPF30 +组为 3。结论 :三种不同SPF值产品对皮肤的光毒性有一定差异 ,提示SPF值在 2 8以内的防晒制剂皮肤安全性较好 ,SPF30 +的防晒制剂对皮肤有一定光毒刺激反应。     

不同脑保护方法中炎症反应对脑组织的影响

目的 通过观察体外循环中采用不同脑保护方法时脑组织中各种炎性细胞因子的变化，探讨脑保护对炎症反应的影响。方法 将18只健康成年杂种犬随机均分为3组：常温体外循环组（normothermic cardiopulmonary bypass，NCPB组），深低温停循环组（deep hypothermic circulatory arrest，DHCA组），深低温停循环＋间断选择性顺行性脑灌注组（intermittent selective antegrade cerebral perfusion，ISACP，DHCA＋ISACP组）。术后检测犬脑组织的含水量，分离并取出海马，制备脑组织匀浆，采用放射免疫法测定白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF—α）的含量。在透射电子显微镜（TE）下检测海马脑组织的细胞形态学变化。结果 DHCA组的IL-1β和TNF—α含量明显高于NCPB组和DHCA＋ISACP组（P〈0．01），但NCPB组与DHCA＋ISACP组间比较差别无统计学意义（P〉0．05）；TNF—α和IL-1β含量与脑水肿的程度呈正相关（r=0．987，0．942；P〈0．01）。TE检查显示DHCA组超微结构破坏较严重，而NCPB组和DHCA＋ISACP组破坏较轻。结论 长时间DHCA会造成脑损伤，DHCA＋ISACP有一定的脑保护作用，IL-1β和TNF—α在长时间DHCA中对脑损伤起一定的作用。     

低分子肝素对不稳定型心绞痛病理生理干预作用的研究

目的:观察低分子肝素(LMWH)对不稳定型心绞痛((UAP)的临床症状、心电图、血脂以及内皮素(ET)的影响。方法:前瞻性地将84例UAP患者随机分为两组:对照组使用硝酸甘油、倍他乐克、阿司匹林等药物;治疗组(LMWH组)在上述治疗基础上加用LMWH(速避凝)。治疗前后调查临床症状以及心电图改变,抽血测定血脂、红细胞压积、血小板及内皮素水平的变化。结果:两组治疗后,患者心绞痛发作次数、持续时间以及硝酸甘油的用量明显减少,心电图明显改善,且LMWH组优于对照组(P<0.05)。LMWH治疗后,患者HCT、TC、TG及ET较治疗前明显降低(P<0.05)。对照组血浆ET水平无变化。结论:LMWH对UAP患者不仅具有抗凝抗栓作用,而且可以降低血液粘度、保护血管内皮细胞,纠正脂类代谢紊乱状态,     

Studies on capsaicin inhibition of chemically induced lipid peroxidation in the lung and liver tissues of rat

Previous work from this laboratory has already indicated that capsaicin, stabilizes the rat lung membrane lipid system on long-term treatment. This stabilization of the membrane is further supported by our present findings that capsaicin pretreatment causes significant inhibition of various chemically induced lipid peroxidative changes at both cellular and subcellular levels. Both in vivo and in vitro studies, using whole lung and liver tissue slices and mitochondrial and microsomal fractions, have shown that capsaicin pretreatment inhibits peroxidative changes at both cellular and subcellular levels. Both in vivo and in vitro studies, using whole lung and liver tissue slices and mitochondrial and microsomal fractions, have shown that capsaicin pretreatment inhibits peroxidative changes induced by different chemical irritants such as chloroform, dichloromethane, carbon tetrachloride as well as ferrous sulphate.