Doxorubicin-conjugated biodegradable polymeric micelles having acid-cleavable linkages.

Doxorubicin was chemically conjugated to the terminal end of a di-block copolymer composed of poly(L-lactic acid) (PLLA) and methoxy-poly(ethylene glycol) (mPEG) via two acid-cleavable linkages. A hydrazone bond and a cis-acotinyl bond were formed between doxorubicin and the terminal group of PLLA segment in the block copolymer. Doxorubicin-conjugated PLLA-mPEG di-block copolymers self-assembled to form micelles in aqueous solution. The doxorubicin-conjugated micelles were about 89.1 nm in diameter and their critical micelle concentration was 1.3 microg/ml. These values were comparable with those of unconjugated micelles. In an acidic condition, the conjugated doxorubicin in the hydrazone linkage was readily cleaved, releasing doxorubicin in an intact structure. Doxorubicin-conjugated PLLA-mPEG micelles were more potent in cell cytotoxicity than free doxorubicin, suggesting that they were more easily taken up within cells with concomitant rapid release of cleaved doxorubicin into the cytoplasm from acidic endosomes.     

氟康唑食管给药与静脉给药的药代动力学对比研究

目的:进行氟康唑食管给药与静脉给药的药代动力学研究。方法:采用HPLC法测定14名受试者静脉及食管给予氟康唑后经时血浓度,比较药代动力学参数及药物生物利用度变化。结果:两种给药途径,氟康唑主要药代动力学参数Cmax为(13.31±1.38)和(10.93±0.73)μg/ml,Tmax为(1.04±0.19)和(1.74±0.73)h,T1/2为(40.77±7.13)和(40.05±4.90)h,AUC为(271.09±30.48)和(261.93±32.60)μg/ml·h。食管给药生物利用度为(95.93±6.49)%,两种给药途径的生物利用度无统计学差异(P>0.05)。结论:食管给药是一种安全有效的给药方法。     

气升式发酵罐发酵黄原胶的动力学

利用黄单孢菌研究了在50L气升式发酵罐发酵黄原胶的动力学,在logistic方程和Luedeking Piret方程的基础上,建立了两步发酵黄原胶的动力学模型,并对模型和实验数据进行了比较,进一步在200L相似结构的气升式发酵罐中的试验表明,该模型能较好的对发酵动力学进行描述.     

某医院传染性非典型肺炎疫情分析

目的：分析某医院SARS疫情的发生、发展及控制过程，为疫情控制提供一定的参考依据。方法：依照卫生部推荐的统一个案调查表和临床诊断标准，描述疫情的三间分布以及发放防护用品的数量与病例数的关系。结果：某医院疫情暴发曲线由3个暴发高峰组成，前两个峰较大，后一个峰较小，呈散发。提示病例传染共形成“三代”流行。结论：采用严密的综合防护措施，能够彻底控制SARS疫情在医院的暴发。     

氯喹对全肝缺血再灌注大鼠肺损伤的保护作用

目的 探讨氯喹对全肝缺血再灌注大鼠急性肺损伤（Au）的保护作用及其机制。方法 健康SD大鼠90只，雌雄不拘，体重300～350g，随机分为3组：假手术组（A组）、全肝缺血再灌注组（B组）、全肝缺血再灌注＋氯喹组（C组），每组30只。阻断肝门及肝上、肝下下腔静脉20min时开放血流，建立大鼠全肝缺血再灌注模型。C组于缺血前即刻经股静脉注射氯喹10mg／kg，A、B组给予等量生理盐水。于缺血20min、再灌注4h时每组分别处死10只大鼠，抽取门静脉血，测定血浆D-乳酸、内毒素（ETX）、肿瘤坏死因子-a（TNF-a）浓度，另外10只用于观察再灌注48h时大鼠生存率，并在电镜下观察肺组织超微结构的改变。结果 缺血再灌注可导致大鼠缺血期和再灌注期门静脉血D-乳酸、ETX、TNF-a浓度升高，大鼠生存率降低，肺组织超微结构严重受损，氯喹可减弱全肝缺血再灌注导致的上述改变。结论 氯喹对全肝缺血再灌注大鼠ALI有一定的保护作用，通过抑制磷脂酶A2激活，降低肠粘膜屏障通透性升高，降低肠黏膜内毒素移位。     

Clinical utility of trapezius muscle studies in the evaluation of amyotrophic lateral sclerosis.

Needle electromyography (EMG) and determining the motor evoked potential (MEP) of the genioglossus (tongue) are difficult to perform in evaluation of the craniobulbar region in patients with amyotrophic lateral sclerosis (ALS). Needle EMG and MEP determination in the upper trapezius were carried out in 17 consecutive ALS patients. The needle EMG parameters recorded included abnormal spontaneous activity and motor unit action potential morphology. An upper motor neuron lesion was presumed when either response to cortical stimulation was absent, or the central conduction time was delayed (>mean + 2 SD). Of the 12 patients with limb-onset ALS, using needle EMG, 11 were found to have abnormalities in the upper trapezius, and only five in the tongue. Three of the six patients with isolated limb involvement had abnormal MEP findings. In conclusion, electrophysiological studies of the upper trapezius are useful in ALS patients without bulbar symptoms.     

低强度激光照射诱导大鼠胸主动脉金属硫蛋白的生成

目的：观察低强度红激光照射对大鼠脑主动脉金属硫蛋白（metallothionein,MT)生成的影响，探讨激光照射的细胞保护机制。方法：取24只大鼠的胸主动脉，将其制成厚度为0．5mm的薄片，置于含10％胎牛血清Krebs-Henseleit液6孔培养板，经95％O2－5％CO2、37℃孵育。设对照组及3个实验组，对照组不照射激光，3个实验组分别以功率密度为3、6和12J／cm^2的632nm波长的激光照射。采用竞争性RT－PCR法测定胸主动脉内MT的mRNA水平变化，以^109Cd牛血红蛋白饱和法测定MT的含量。结果：3个实验组MT1 mRNA水平分别比对照组增加175％（P＞0.05)、418．6％（P＜0．05）和668．2％（P＜0．01）；MT2 mRNA水平分别比对照组增加163．9（P＞0．05）、615％、（P＜0．01）和1087％（P＜0．01）；相应的MT蛋白含量分别比对照组增加142．8％（P＜0．05）、170．8％（P＜0．05）和142．1％（P＜0．05）。     

内源性转化生长因子β1对膀胱癌细胞体外生长的影响

目的：研究内源性转化生长因子β1（TGFβ1）对膀胱癌细胞增殖的影响及机制。方法：构建携TGFβ1反义RNA的复制缺陷型逆转录病毒载体pRevTβ-AS，转染膀胱癌EJ细胞株，观察抑制内源性TGFβ1表达对EJ细胞体外增殖的影响；流式细胞仪分析转染后细胞周期时相分布的改变。结果：将TGFβ1反义RNA导入EJ细胞并有效表达；抑制TGFβ1表达可以降低靶细胞的生长速度和克隆形成率，使细胞增殖指数下降12％；反义RNA转染的EJ细胞G0和G1期细胞占65．7％，高于对照组细胞，S期细胞占20．5％，低于对照组细胞。结论：内源性TGFβ1通过诱导膀胱癌细胞G1→S期转换，促进肿瘤细胞体外增殖。     

Can a leukocyte depletion filter (LDF) reduce the risk of reintroduction of hepatocellular carcinoma cells?

During liver transplantation for hepatocellular carcinoma (HCC) patients, HCC could theoretically be introduced into the systemic circulation when salvaged blood is used with an autotransfusion device. Several reports have shown that some types of leukocyte depletion filters (LDFs) could completely reduce the risk for reintroducing some types of tumor cells. In this study, we tested the ability of the LDF (RCEZ1T, Pall Biomedical Co, NY, USA) to reduce the risk for reintroducing HCC cells in vitro by using a very sensitive detection method. We divided the test group into 6 groups: group I was 10 cells, group II was 20 cells, group III was 2 x 10(3) cells, group IV was 2 x 10(5) cells, group V was 2 x 10(6) cells, and group VI was 2 x 10(7) cells. The counted cells in 200 mL saline were passed through the RCEZ1T using the force of gravity. To identify the presence of cells, the pellet was resuspended, and polymerase chain reaction (PCR) was performed. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a housekeeping gene, was used as a primer. In groups I and II, the HCC cells were completely filtered in all experiments. However, in groups III, IV, and V, the HCC cells were not completely filtered in a few of the repeated experiments, with the unfiltered rate of tumor cells being between 8% and 20%. In group VI, the HCC cells were not completely filtered in all the repeated experiments. In conclusion, the RCEZ1T filter markedly reduced the risk for reintroduction of HCC cells. However, at high HCC cell load the filter cannot completely remove all the tumor cells. Further studies are required to assess the impact in clinical settings.