人源性多肽pCM-19抗菌机制的初步研究

目的：初步分析人源性多肽pCM-19的抗菌作用机制。方法：利用荧光素掺入破损细胞膜的原理，采用流式荧光激活细胞分析（FACScan）和扫描电子显微镜分析pCM-19对靶菌膜的作用机制。结果：FACS分析法结果显示pCM-19处理后的大肠杆菌PI着染细菌比例明显高于未处理组，并且随作用时间的延长，PI着染BL-21菌比例增大，20min时达最高水平，20min以后反而降低；扫描电子显微镜观察到pCM-19处理后的大肠杆菌有明显的表面形态学的改变，如细菌体积缩小、细菌表面出现皱缩、凹陷似有孔洞形成。结论：人源性多肽pCM-19可能作用于细菌细胞壁和（或）细胞膜，通过改变其通透性而发挥杀菌作用。     

The Effect of Second-Trimester Antibiotic Therapy on the Rate of Preterm Birth

ObjectiveAs many as 50% of spontaneous preterm births are infection-related, with Mycoplasma species being the most common microbial isolates from the amniotic cavity. The goal of our study was to evaluate the effect of macrolides, a specific group of antibiotics known to be effective against Mycoplasma species, on the rate of preterm births.MethodsWe performed a systematic review of the literature and a meta-analysis. We searched PubMed, Medline (1965–March 2006), Embase, and the Cochrane Library, using the key words “pregnancy,” “macrolides,” “erythromycin,” “azithromycin,” and “clarithromycin.” The research was limited to randomized controlled trials and to human females. Studies included for analysis were of women in the second trimester of pregnancy who received either macrolides or placebo (or no treatment) in order to prevent preterm delivery with at least 95% of patient follow-up. We excluded studies involving women with preterm premature rupture of membranes or regular uterine contractions. Meta-analysis of the retrieved data was performed using RevMan 4.2.8 (Cochrane Collaboration) with dichotomous analyses and delivery prior to 37 weeks’ gestation as the primary outcome. The analysis was subsequently repeated using the same methodology for clindamycin and metronidazole administered during the second trimester.ResultsOf the 61 articles yielded by our search, three original papers, investigating a total of 1807 women, examined macrolide utilization and met our criteria. Women included in our analysis were all considered to be at higher risk for preterm delivery (vaginal fetal fibronectin positivity, urogenital Mycoplasma infection, prior preterm delivery, and/or pregestational maternal weight < 50 kg). Compared with placebo, macrolides were associated with a lower rate of preterm births (odds ratio [OR] 0.72; 95% confidence intervals [CI] 0.56–0.93), as was clindamycin (OR 0.68; 95% CI 0.49–0.95). On the other hand, metronidazole (OR 1.10; 95% CI 0.95–1.29) was not linked with significant changes in the rate of preterm births. A higher rate of preterm delivery was found when mid-trimester metronidazole was the only antibiotic administered (OR 1.31; 95% CI 1.08–1.58).ConclusionMacrolides and clindamycin, given during the second trimester of pregnancy, are associated with a lower rate of preterm delivery, whereas second-trimester metronidazole used alone is linked with a greater risk of preterm delivery in a high-risk population. Use of metronidazole, a common treatment for bacterial vaginosis and Trichomonas vaginalis, should be avoided during the second trimester of pregnancy in this population.     

Ⅳ型胶原、MMP-9和TIMP-1基因表达在早期放射性肺纤维化启动中的作用

目的 观察早期放射性肺纤维化启动过程中Ⅳ型胶原、明胶酶B(MMP-9)、金属蛋白酶1组织抑制剂(TIMP-1)的基因表达特点,探讨其在放射性肺损伤中的作用.方法 C57小鼠于20Gy 60Co γ射线全肺照射后照射后1、2、4周活杀,每个时间点分别配有相应的正常对照组.RT-PCR检测Ⅳ型胶原、MMP-9、TIMP-1 mRNA水平的变化,并应用图像分析仪测定电泳条带的平均光密度值.结果 Ⅳ型胶原mRNA于照射后1周开始增高(0.202),4周达高峰(0.340);MMP-9 mRNA于照射后1周即有明显增高并且达到高峰(0.730),于第2周开始降低(0.592);TIMP-1 mRNA于照射后1周开始轻度增加(0.987),4周时达高峰(2.027).结论 60Co γ射线可刺激Ⅳ型胶原、MMP-9和TIMP-1 mRNA的表达,但随照射后时间的延长呈现不同的变化趋势,它们之间的相互制约导致了放射性肺损伤早期的组织重建,与后来形成的肺纤维化有必然的内在联系.     

Pten基因敲除对过氧化物酶家族表达和活性氧水平的影响

目的:探讨Pten基因敲除后对过氧化物酶家族(Peroxiredoxins,Prdxs)水平和活性氧水平的影响.方法:采用Western印迹和化学/荧光发光分析法分别检测了在Pten / MEF和Pten-/-MEF细胞中PRDXs的表达和细胞内活性氧水平.结果:Western印迹结果显示,与Pten / MEF细胞相比,Pten-/-MEF细胞PRDX Ⅰ,Ⅱ,Ⅴ,Ⅵ蛋白水平下调,PRDX Ⅲ不变,PRDX Ⅳ上调.DCFH探针标记后流式结果显示Pten-/-MEF 细胞活性氧荧光值显著高于对照Pten / MEF细胞(P＜0.05).结论:Pten基因敲除引起数种PRDXs表达下调,细胞内活性氧水平增高.     

Effect of environment on extremely severe road traffic crashes：retrospective epidemic analysis during 2000-2001

Objective: To make an epidemiological analysis of the effect of environment on extremely severe road traffic crashes (RTCs). Methods: Epidemiologic data of extremely severe RTCs associated with environmental factors, including weather, topography, road conditions and other traffic conditions in Mainland China during 2000-2001, were collected and analyzed. Results: ( 1 ) During 2000-2001, there were 3 365 extremely severe RTCs with 13 666 deaths, 12 204 injuries and a direct economical loss of 136 million RMB. ( 2 ) Most extremely severe RTCs occurred in fine weather days and in the daytime. The high occurrence sites were plain areas, horizontal and straight roads, Grade B and C roads, ordinary road segment, and asphalt, smooth and mixed roads. (3) Compared with other RTCs, extremely severe RTCs were more likely to happen under following conditions: on cloudy, snowing, misty and blustering days; in hill and mountainous areas; on crooked and sloping roads; on freeway, Grade A, B, and C roads; mixed roads; ordinary, bridge, narrow and transitional roads; sand and dirt-roads; without traffic control measures; night without lighting. (4) Extremely severe RTCs of mountainous area or crooked and sloping roads were most severe in terms of deaths and injures per crash. Conclusions: Extremely severe RTCs are closely related with environmental factors. Rational road programming, enhancing road establishment and improving road conditions are probably effective measures to reduce the road traffic injuries.     

沙漠热环境负重行军对淋巴细胞HSP70的影响

目的：探讨沙漠热环境负重行军血淋巴细胞HSP70的变化规律。方法：对沙漠干热环境中以不同速度和时间负重行军的54名战士和14名对照血淋巴细胞HSP70进行对比分析。结果：相同行军时间的不同行军速度间淋巴细胞HSP70有显性差异（P＜0．05）；3．5km/h行军3h组淋巴细胞HSP70明显高于对照和行军2h组（P＜0．05）：5．0km/h行军1．2h组血淋巴细胞HSP70明显高于对照和行军3h组（P＜0．05）。结论：随行军速度和时间的增加，淋巴细胞HSP70增高；当行军速度和时间达到一定水平后，机体淋巴细胞HSP70明显增加。血淋巴细胞HSP70作为热损伤和热耐受的监测指标较血浆HSP70敏感。     

类黄酮物质抗动脉粥样硬化作用研究进展

人类植物性膳食成分中存在丰富的类黄酮物质，具有多种生物活性。近几年的流行病学研究和试验研究显示，类黄酮物质可以抑制动脉粥样硬化的发生与发展，从而降低心脑血管疾病的发生率和死亡率。本就类黄酮物质抗动脉粥样硬化的作用机制作一综述。