Identification of a putative Salmonella enterica serotype typhimurium host range factor with homology to IpaH and YopM by signature-tagged mutagenesis

The genetic basis for the host adaptation of Salmonella serotypes is currently unknown. We have explored a new strategy to identify Salmonella enterica serotype Typhimurium (S. typhimurium) genes involved in host adaptation, by comparing the virulence of 260 randomly generated signature-tagged mutants during the oral infection of mice and calves. This screen identified four mutants, which were defective for colonization of only one of the two host species tested. One mutant, which only displayed a colonization defect during the infection of mice, was further characterized. During competitive infection experiments performed with the S. typhimurium wild type, the mutant was defective for colonization of murine Peyer's patches but colonized bovine Peyer's patches at the wild-type level. No difference in virulence between wild type and mutant was observed when calves were infected orally with 10(10) CFU/animal. In contrast, the mutant possessed a sixfold increase in 50% lethal morbidity dose when mice were infected orally. The transposon in this mutant was inserted in a 2.9-kb pathogenicity islet, which is located between uvrB and yphK on the S. typhimurium chromosome. This pathogenicity islet contained a single gene, termed slrP, with homology to ipaH of Shigella flexneri and yopM of Yersinia pestis. These data show that comparative screening of signature-tagged mutants in two animal species can be used for scanning the S. typhimurium genome for genes involved in host adaptation.     

锌对培养的乳鼠心肌细胞自发性搏动和电活动的影响

本文研究了不同浓度的Zn对培养的乳鼠心肌细胞自发性搏动及心肌细胞动作电位的影响。实验结果表明,加Zn在0.125—2ppm范围内,自发性搏动群落的出现率增高,与对照组比较,P<0.001。但Zn的浓度超过一定范围(4 ppm),自发搏动率则呈降低趋势;8 ppm组明显低于对照组,P<0.01.Zn对心肌细胞动作电位的影响表现为动作电位的发放频率减慢,波幅降低,波宽变窄和最大除极速度减慢。     

流行性脑脊髓膜炎的流行趋势变化与其疫苗接种

在过去几十年,随着疫苗的广泛使用,不同国家和区域引起流行性脑脊髓膜炎(简称流脑)病原体的血清群也发生了变迁。本文将脑膜炎球菌疫苗免疫接种、感染人群、不同区域和国家流脑的流行趋势及其内在机制研究进展进行综述,为进一步了解流脑流行趋势变化与其疫苗接种和后续制定免疫策略提供参考。     

丹参多酚酸盐通过AMPK/Sirt1/PGC-1α信号通路诱导膜性肾病大鼠足细胞自噬的机制

目的：通过观察丹参多酚酸盐对膜性肾病(MN)大鼠肾组织中腺苷酸活化蛋白激酶(AMPK)、沉默信息调节因子(Sirt1)、过氧化物酶体增殖物激活受体γ辅激活因子-1α(PGC-1α)蛋白的表达及细胞自噬和凋亡的情况,探讨其治疗MN的可能的分子机制。方法：80只雄性SD大鼠随机分为正常组,模型组,盐酸贝那普利组(10 mg·kg^-1),丹参多酚酸盐低、中、高剂量组(16.7、33.3、66.7 mg·kg^-1),通过尾静脉注射阳离子化牛血清白蛋白(C-BSA)的方法造模。造模成功后,各组按照相应比例剂量连续给药4周后留取24 h尿、血清和肾组织,尿液用于检测24 h尿蛋白定量(24 h UTP)、血清用于检测血尿素氮(BUN)、血肌酐(SCr)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、丙二醛(MDA)的含量。采用光镜、电镜、免疫荧光法观察肾脏病理学变化,蛋白免疫印迹法(Western blot)检测大鼠肾组织磷酸化(p)-AMPK、AMPK、p...     

SARS-CoV-2 Aerosol Exhaled by Experimentally Infected Cynomolgus Monkeys

We analyzed size of severe acute respiratory coronavirus 2 (SARS-CoV-2) aerosol particles shed by experimentally infected cynomolgus monkeys. Most exhaled particles were small, and virus was mainly released early during infection. By postinfection day 6, no virus was detected in breath, but air in the isolator contained large quantities of aerosolized virus.     

婴儿期生长情况对青春期性发育的影响研究

目的 探讨婴儿期快速生长对青春期性发育的影响,对预防未来青春期提早发育提供依据。方法 选择2004年1月-2005年1月在温州市儿童医院及本院体检的198例生长过快的婴儿为观察组,另选择175名正常婴儿为对照组。根据出现月经初潮/遗精的时间点,把观察组分成性早熟组和正常发育组。采用Spearman相关性分析观察组婴儿1周岁的身高Δ值、体重Δ值与青春期性早熟的相关性。结果 观察组婴儿1周岁的身高Δ值、体重Δ值均显著大于对照组,差异有统计学意义(t＝2.085,2.146,P＜0.05);观察组儿童的身高、体重、体脂、骨龄值均显著大于对照组儿童,观察组儿童的T、E2、FSH、LH水平均显著高于对照组儿童,差异均有统计学意义(P＜0.05)。对照组无性早熟患儿。观察组、早熟组和正常组的男女比例对比,差异无统计学意义(P＞0.05)。早熟组身高、体重、体脂、骨龄值均显著大于正常组,早熟组T、E2、FSH、LH水平均显著高于正常组,差异有统计学意义(P＜0.05)。观察组婴儿1周岁的身高Δ值、体重Δ值与青春期性早熟呈正相关(r=0.816,0.872,P<0.001)。结论 婴儿期快速生长可造成儿童青春期前肥胖和体脂过度,使青春期早发。控制婴儿期过快生长对预防未来青春期提早发育有重要意义。     

二维超声诊断胎儿脐带绕颈136例分析

目的 了解胎儿脐带绕颈时对胎儿安危及窘迫和缺氧的影响程度。方法 采用日本Aloka-630型超声诊断仪,孕妇孕周为28-42周。结果 二维超声诊断胎儿脐带绕颈136例,经分娩证实129例。符合率94.85%。结论 二维超声诊断与分娩后证实比较,超声是诊断脐带绕颈的可靠方法之一。为分娩方式提供依据。     

颅脑创伤急性期外周血白细胞变化的临床意义

目的 探讨颅脑创伤急性外周血白细胞（PWBC）数及中性粒细胞（PMN）比例与病情及预后的关系。方法 回顾性分析总结50例颅脑创伤急性期外周血白细胞数及性粒细胞比例,根据病情或预后分组分别进行比较。结果 颅脑创伤病情重者较病情轻者PWBC数与PWM比例显著提高（P＜0．05,P＜0．001）;恢复不良组及死亡组与恢复良好组相比,PWBC数显著增高（P＜0．05,P＜0．01）。结论 临床监测PWBC数及PMN比例可作为颅脑创伤患者的病情判断和预后估计的一项辅助指标。     

曲美他嗪治疗稳定劳累型心绞痛患者的临床研究

目的：评价曲美他嗪与合心爽联合治疗稳定劳累型心绞痛的临床效果。方法：经服用合心爽不能有效控制的稳定劳累型心绞痛患40例,被随机分为联合曲美他嗪治疗组和单用合心爽治疗组,经治疗后评价两组心绞痛发作频度。结果;联合曲美他嗪治疗后患心绞痛的每周发作次数、动态心电图监测心肌缺血时间及硝酸甘油消耗量均有明显下降。结论：合心爽不能有效控制的稳定劳累型心绞痛患,联合应用曲美他嗪治疗能明显增加临床疗效,而不影响血液动力学。