目的探讨颈交感神经干离断(transection of the cervical sympathetic trunk,TCST)对大鼠溃疡性结肠炎(ulcerative colitis,UC)的作用。方法成年雄性清洁级Wistar大鼠72只,随机分为3组,每组24只。A组:用0.9%氯化钠溶液灌肠,暴露右侧颈...目的探讨颈交感神经干离断(transection of the cervical sympathetic trunk,TCST)对大鼠溃疡性结肠炎(ulcerative colitis,UC)的作用。方法成年雄性清洁级Wistar大鼠72只,随机分为3组,每组24只。A组:用0.9%氯化钠溶液灌肠,暴露右侧颈交感神经干,不离断;B组:用4%乙酸灌肠,暴露右侧颈交感神经干,不离断;C组:用4%乙酸灌肠,暴露并离断右侧颈交感神经干。观察大鼠体重及一般状况,分别于术后3、7、14d每组取8只取材,用血清和组织匀浆检测各项生化指标并制作病变最明显处结肠病理切片。结果与A组比较,B、C组血清及肠组织中NO浓度和iNOS活性以及血清白介素-6(IL-6)浓度均升高(P<0.05),但C组升高程度明显低于B组(P<0.01);与A组比较,B、C组血清及肠组织中SOD活性降低(P<0.05),但C组降低的程度明显低于B组(P<0.01)。结论TCST能降低UC大鼠NO、IL-6含量及iNOS活性,提高其SOD活性,从而减轻对结肠黏膜的损害,促进UC的恢复。展开更多
Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished...Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished on coherence sections （time slices or profiles） due to interferences from adjacent strata, especially these with strong reflectivity. In this paper, we propose a coherence enhancement method which applies local histogram specification （LHS） techniques to enhance subtle faults or fractures in the coherence cubes. Unlike the traditional histogram specification （HS） algorithm, our method processes 3D coherence data without discretization. This method partitions a coherence cube into many sub-blocks and self-adaptively specifies the target distribution in each block based on the whole distribution of the coherence cube. Furthermore, the neighboring blocks are partially overlapped to reduce the edge effect. Applications to real datasets show that the new method enhances the details of subtle faults and fractures noticeably.展开更多
Vascular endothelial growth factor （VEGF） is a potent secreted mitogen critical for physiologic and tumor angiogenesis. Regulation of VEGF occurs at several levels, including transcription, mRNA stabilization, trans...Vascular endothelial growth factor （VEGF） is a potent secreted mitogen critical for physiologic and tumor angiogenesis. Regulation of VEGF occurs at several levels, including transcription, mRNA stabilization, translation, and differential cellular localization of various isoforms. Recent advances in our understanding of post-transcriptional regulation of VEGF include identification of the stabilizing mRNA binding protein, HuR, and the discovery of internal ribosomal entry sites in the 5＇UTR of the VEGF mRNA. Monoclonal anti-VEGF antibody was recently approved for use in humans, but suffers from the need for high systemic doses. RNA interference （RNAi） technology is being used in vitro and in animal models with promising results. Here, we review the literature on post-transcriptional regulation of VEGF and describe recent progress in targeting these mechanisms for therapeutic benefit.展开更多
Optical coherence tomography(OCT) is an optical imaging modality that performs high-resolution,cross-sectional,subsurface tomographic imaging of the microstructure of tissues.The physical principle of OCT is similar t...Optical coherence tomography(OCT) is an optical imaging modality that performs high-resolution,cross-sectional,subsurface tomographic imaging of the microstructure of tissues.The physical principle of OCT is similar to that of B-mode ultrasound imaging,except that it uses infrared light waves rather than acoustic waves.The in vivo resolution is 10-25 times better(about 10 μm) than with high-frequency ultrasound imaging,but the depth of penetration is limited to 1-3 mm,depending upon tissue structure,depth of focus of the probe used,and pressure applied to the tissue surface.In the last decade,OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice,including the gastrointestinal(GI) tract and pancreatic-biliary ductal system.OCT imaging from the GI tract can be done in humans by using narrow-diameter,catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope,for investigating the epithelial structure of the GI tract,or a side-view endoscope,inside a standard transparent ERCP catheter,for investigating the pancreatico-biliary ductal system.Esophagus and the esophago-gastric junction has been the most widely investigated organ so far;more recently,also duodenum,colon and pancreatico-biliary ductal system have been extensively investigated.OCT imaging of the gastro-intestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa,lamina propria,muscularis mucosae,andpart of the submucosa.The technique may be,therefore,used to identify pre-neoplastic conditions of the GI tract,such as Barrett's epithelium and dysplasia,and evaluate the depth of penetration of early-stage neoplastic lesions.OCT imaging of the pancreatic and biliary ductal system could improve the diagnostic accuracy for ductal epithelial changes and the differential diagnosis between neoplastic and non-neoplastic lesions.展开更多
文摘目的探讨颈交感神经干离断(transection of the cervical sympathetic trunk,TCST)对大鼠溃疡性结肠炎(ulcerative colitis,UC)的作用。方法成年雄性清洁级Wistar大鼠72只,随机分为3组,每组24只。A组:用0.9%氯化钠溶液灌肠,暴露右侧颈交感神经干,不离断;B组:用4%乙酸灌肠,暴露右侧颈交感神经干,不离断;C组:用4%乙酸灌肠,暴露并离断右侧颈交感神经干。观察大鼠体重及一般状况,分别于术后3、7、14d每组取8只取材,用血清和组织匀浆检测各项生化指标并制作病变最明显处结肠病理切片。结果与A组比较,B、C组血清及肠组织中NO浓度和iNOS活性以及血清白介素-6(IL-6)浓度均升高(P<0.05),但C组升高程度明显低于B组(P<0.01);与A组比较,B、C组血清及肠组织中SOD活性降低(P<0.05),但C组降低的程度明显低于B组(P<0.01)。结论TCST能降低UC大鼠NO、IL-6含量及iNOS活性,提高其SOD活性,从而减轻对结肠黏膜的损害,促进UC的恢复。
基金sponsored by Important National Science and Technology Specific Projects of China (Grant No.2008ZX05023-005-011 and No. 2008ZX05040-003)the National 973 Program of China (Grant No. 2006CB202208)
文摘Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished on coherence sections （time slices or profiles） due to interferences from adjacent strata, especially these with strong reflectivity. In this paper, we propose a coherence enhancement method which applies local histogram specification （LHS） techniques to enhance subtle faults or fractures in the coherence cubes. Unlike the traditional histogram specification （HS） algorithm, our method processes 3D coherence data without discretization. This method partitions a coherence cube into many sub-blocks and self-adaptively specifies the target distribution in each block based on the whole distribution of the coherence cube. Furthermore, the neighboring blocks are partially overlapped to reduce the edge effect. Applications to real datasets show that the new method enhances the details of subtle faults and fractures noticeably.
文摘Vascular endothelial growth factor （VEGF） is a potent secreted mitogen critical for physiologic and tumor angiogenesis. Regulation of VEGF occurs at several levels, including transcription, mRNA stabilization, translation, and differential cellular localization of various isoforms. Recent advances in our understanding of post-transcriptional regulation of VEGF include identification of the stabilizing mRNA binding protein, HuR, and the discovery of internal ribosomal entry sites in the 5＇UTR of the VEGF mRNA. Monoclonal anti-VEGF antibody was recently approved for use in humans, but suffers from the need for high systemic doses. RNA interference （RNAi） technology is being used in vitro and in animal models with promising results. Here, we review the literature on post-transcriptional regulation of VEGF and describe recent progress in targeting these mechanisms for therapeutic benefit.
文摘Optical coherence tomography(OCT) is an optical imaging modality that performs high-resolution,cross-sectional,subsurface tomographic imaging of the microstructure of tissues.The physical principle of OCT is similar to that of B-mode ultrasound imaging,except that it uses infrared light waves rather than acoustic waves.The in vivo resolution is 10-25 times better(about 10 μm) than with high-frequency ultrasound imaging,but the depth of penetration is limited to 1-3 mm,depending upon tissue structure,depth of focus of the probe used,and pressure applied to the tissue surface.In the last decade,OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice,including the gastrointestinal(GI) tract and pancreatic-biliary ductal system.OCT imaging from the GI tract can be done in humans by using narrow-diameter,catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope,for investigating the epithelial structure of the GI tract,or a side-view endoscope,inside a standard transparent ERCP catheter,for investigating the pancreatico-biliary ductal system.Esophagus and the esophago-gastric junction has been the most widely investigated organ so far;more recently,also duodenum,colon and pancreatico-biliary ductal system have been extensively investigated.OCT imaging of the gastro-intestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa,lamina propria,muscularis mucosae,andpart of the submucosa.The technique may be,therefore,used to identify pre-neoplastic conditions of the GI tract,such as Barrett's epithelium and dysplasia,and evaluate the depth of penetration of early-stage neoplastic lesions.OCT imaging of the pancreatic and biliary ductal system could improve the diagnostic accuracy for ductal epithelial changes and the differential diagnosis between neoplastic and non-neoplastic lesions.
