世界胃肠病学组织全球指南——发展中国家幽门螺杆菌感染

世界上有一半人口感染幽门螺杆菌（H．pylori）,其感染率因地理位置、种族、年龄和社会经济状况不同而存在很大差异．在发展中国家较高．发达国家较低。但总体而言,近年世界许多地区的H．pylori感染率均呈下降趋势。     

共培养下后交叉韧带成纤维细胞中MMPs的基因表达

目的研究后交叉韧带(posterior cruciate ligament,PCL)成纤维细胞与滑膜细胞共培养下,2种细胞之间的交流对PCL成纤维细胞中基质金属蛋白酶MMP-1、2、3表达及活性的影响。方法分为共培养组和单培养组:①用显微镜观察共培养24 h后细胞的活性和迁移率。②分别培养6 h后,提取总RNA,逆转录PCR;实时荧光定量PCR对人后交叉韧带成纤维细胞MMP-1、2、3基因的表达进行半定量和定量分析。③共培养处理1、2、3 d后收集培养上清液,用明胶酶谱法检测MMP-2的活性。结果共培养使PCL细胞和滑膜细胞较单层细胞培养迁移率分别增高了(43.1±0.1)%和(76.2±0.2)%(P<0.01)。与单培养相比,共培养组明显增加了MMP-2的基因表达,但降低了MMP-1、3的基因表达。酶谱结果表明共培养增加了MMP-2活性(P<0.05)。结论共培养能够促进细胞的迁移以及调节细胞中MMP-1、2、3的表达情况。     

Enhanced amygdala and medial prefrontal activation during nonconscious processing of fear in posttraumatic stress disorder: an fMRI study

Biological models of posttraumatic stress disorder (PTSD) suggest that patients will display heightened amygdala but decreased medial prefrontal activity during processing of fear stimuli. However, a rapid and automatic alerting mechanism for responding to nonconscious signals of fear suggests that PTSD may display heightened rather than decreased MPFC under nonconscious processing of fear stimuli. This study used functional magnetic resonance imaging to examine blood oxygenation level-dependent signal changes during nonconscious presentation (16.7 ms, masked) of fearful and neutral faces in 15 participants with PTSD and 15 age and sex-matched healthy control participants. Results indicate that PTSD participants display increased amygdala and MPFC activity during nonconscious processing of fearful faces. These data extend existing models by suggesting that the impaired MPFC activation in PTSD may be limited to conscious fear processing. Hum Brain Mapp, 2008. (c) 2007 Wiley-Liss, Inc.