由近似边界进行边缘改善的几种珠子链算法的分析和比较

本文提出了由近似边界确定物体边界的简易珠子链算法,该算法较珠子链算法和改进珠子链算法简单。试验证明:加上约束条件的简易珠子链算法比不加约束条件的改进珠子链算法算法精确。     

Distribution of nitric oxide synthase, nerve growth factor receptor and interstitial cells of Cajal in hirschsprung's disease and its significance

Objective To investigate the distribution of nitric oxide synthase (NOS), nerve growth factor receptor (NGFR) and interstitial cells of Caial (ICCs) in Hirschsprung's disease (HD). Methods The distribution of NOS,NGFR and ICCs was studied by using NADPH diaphoruse histochemistry, immanohistochemistry with a monoclonal antibody to human NGFR and the specific polycloual antibody against c-kit in 8 normal controls and 10 cases of HD.Results NOS and NGFR were abundantly present in the myenteric plexus and in the nerve fibers of musculature. ICCs were intensively distributed in the surface of circular musculature and around the myenteric plexus to form a network in normal control colon. In contrast, NOS and NGFR were scarce or absent in the myenteric plexus and in the nerve fibers of musculature, while the hypertrophic nerve trunks were NGFR positive, ICCs were scarcely distributed and the network was disrupted in the aganglionic colon in HD. Conclusion These findings suggest the Involvement of NOS,NGFR and ICCs in the patbophysiology of HD.     

Methylation status of the interferon-gamma gene promoter in chronic hepatitis B

Objective To evaluate the methylation status at CpG site -55 in the interferon-gamma (IFN-7) gene promoter and its effect on IFN-7 expression in chronic hepatitis B. Method The authors recruited 30 patients with UBeAg-positive chronic hepatitis B (CHB), 30 HBeAg-negative CHB patients, and 30 healthy blood donors. Pyrosequeneing was used to determine the methylation status at CpG site -55 in the IFN-γ gene promoter following bisulfite treatment of DNA in peripheral blood mononuclear cells (PBMCs). The expression of IFN-γ was analyzed by real-time RT-PCR and ELISA. HBV DNA in PBMCs was detected by nested PCR. Results The methylation level at CpG site -55 in the IFN-γ gene promoter was significantly increased, resulting in subsequent down-regulation of the expression of this cytoldne in CHB. The methylation level at CpG site -55 was significantly higher in HBeAg-positive patients than in HBeAg-negative ones (P<0.01) and was also significantly higher in PBMCs from HBV DNA-positive patients than from HBV DNA-negative ones (P<0.01) ; the methylation level at CpG site -55 was positively correlated with the amount of HBV DNA in serum (P<0.01). Oonclusion IFN-γ gene expression appears to be regulated by methylation of the IFN-γ gene promoter in CHB; the methylation level at CpG site -55 is associated with HBV infection.     

PPAR-γ激活对血管平滑肌细胞外基质释放及结缔组织生长因子表达的影响

目的观察PPAR-γ激活对血管紧张素Ⅱ诱导的体外培养条件下大鼠血管平滑肌(VSMCs)的细胞外基质(ECM)释放及结缔组织生长因子(CTGF)表达的影响。方法原代培养大鼠VSMCs,用不同浓度PPAR-γ激动剂rosiglitzone和/或抑制剂GW9662、BADGE预处理后,加入0.1μmol/L血管紧张素Ⅱ(AngⅡ)刺激24h。比色法检测各组细胞培养液中羟脯氨酸含量,实时荧光定量RT-PCR方法检测各组三型胶原(ColⅢ)、层粘连蛋白(FN)及CTGFmRNA表达,Western blotting检测各组CTGF、PPAR-γ蛋白表达情况,基于ELISA的DNA-binding检测各组PPAR-γ活性。结果 AngⅡ可增加VSMCs PPAR-γ表达,但明显抑制其活性(P<0.05,vs.Control),PPAR-γ激动剂rosiglitazone可显著增加PPAR-γ蛋白表达及活化(P<0.05,vs.AngⅡ)。rosiglitazone可降低细胞培养液中羟脯氨酸含量,下调VSMCs中ColⅢ、FN、CTGF mRNA表达,抑制CTGF蛋白表达,而其他PPAR-γ激动剂(pioglitazone、15-d-PGJ2)均有相似作用,PPAR-γ拮抗剂GW9662及BADGE可拮抗这一作用。结论在VSMCs中,PPAR-γ激活可抑制AngⅡ诱导的CTGF表达,同时抑制ECM沉积。提示PPAR-γ可能在血管纤维化中起重要作用。     

恒磁场对人脐动脉血管平滑肌细胞胞浆游离钙离子浓度的影响

目的 研究恒磁场对培养的人脐动脉血管平滑肌细胞(VSMC)胞浆内游离钙离子浓度([Ca2 ]i)的影响,探讨恒磁场抑制VSMC增殖的作用机制.方法 离体培养人脐动脉VSMC,不同强度的恒磁场垂直作用于VSMC,应用激光共聚焦显微镜观察恒磁场对VSMC胞浆[Ca2 ]i的影响.结果 5 mT的恒磁场作用于VSMC后10-50 min[Ca2 ]i较对照组明显下降,20 min下降最明显;其平滑肌细胞的Ca2 荧光强度明显弱于对照组,至60 min接近对照组.结论 恒磁场对VSMC胞浆[Ca2 ]i有明显降低作用,可能是抑制VSMC细胞增殖的机制.为经皮冠状动脉成型术(PTCA)术后再狭窄的治疗提供了新的理论基础.     

固体氧化物燃料电池的研究

固体氧化物燃料电池(SOFC)作为一种新型的能量转换装置,由于其具有高能量利用率、环境友好、燃料选择广泛等特性,已经引起了学者的广泛关注。随着世界各国对环保问题关注的升温,友好型能源的开发利用已经成为国家能源发展的重要方向,在国家政策的推动下,高校和相关研究机构也加大了研究力度,争取在环境友好型能源的开发利用上抢占先机。文章主要针对目前SOFC的发展现状进行分析,并对SOFC未来的发展提出合理化建议。希望通过以上的论述,能对SOFC的发展起到促进作用。     

10例癌肉瘤的光镜及角蛋白免疫细胞化学

本研究结果示肉瘤样成份与癌灶相比,二者不仅在形态及某些功能特点上不同,而且在免疫角蛋白的表达方面也呈现出显著差异,各例之癌灶不论其为鳞癌,囊腺癌或导管癌,也不论其分化程度如何均呈现出不同强度的棕色角蛋白阳性颗粒,而肉瘤成份则无1例为阳性,提示本组病例中的两种成份各源于上皮及间叶细胞.本病肉瘤样成份形态多样,据此将该瘤分为梭形细胞型、巨细胞瘤型、腺泡型及多形细胞型等四种组织类型。     

体外循环期间血浆与红细胞内钾的改变及补钾方法探索

作者观察了30例心内直视手术患者于体外循环前、中、后血浆钾及红细胞内钾的变化及其影响因素,并分析钾的补充量,发现:灌注前、中的低血钾倾向主要是由于钾向红细胞内转移,而在灌注后主要是尿钾排泄所致;钾的内转移主要受低温、灌注时间及血pH的影响;转流中血钾在4.0m mol/L以下时可导致细胞内钾丢失,提出灌注中补钾量应至少>1.56m mol/kg才能维持血钾在4.0 m mol/L以上。     

有机锗多酸衍生物对S_(180)肿瘤细胞DNA合成的抑制作用

目的　探讨有机锗多酸衍生物对S1 80 肿瘤细胞DNA合成的抑制作用。方法　用3H TdR掺入法检测有机锗多酸衍生物在体外对S1 80 肿瘤细胞DNA合成的抑制作用 ,观察不同剂量有机锗多酸衍生物对S1 80 实体瘤的抑制作用和对免疫器官的影响。结果　体外实验表明 ,有机锗多酸衍生物对S1 80 细胞的生长具有明显的抑制作用 ,而且浓度越高 ,抑制作用越强。体内实验也表明 ,有机锗多酸衍生物对S1 80 实体瘤的生长具有抑制作用 ,而且剂量越大 ,抑制作用越强。且有机锗多酸衍生物可防止荷瘤鼠脾脏重量的下降。结论　有机锗多酸衍生物可抑制肿瘤细胞生长 ,并存在剂量依赖关系     

大鼠骨髓间充质干细胞骨向分化及体外诱导实验

目的建立骨髓间充质干细胞(MSCs)体外分离培养体系,进行骨向分化诱导,并将诱导的成骨细胞复合钛网体外成骨,为MSCs进一步的临床应用研究提供实验依据。方法用密度梯度离心法分离大鼠骨髓MSCs,并对其形态学特征进行观察。用诱导剂对MSCs向成骨细胞进行诱导分化,并进行形态学观察和免疫细胞化学检测。用扫描电镜观察骨向诱导后细胞复合钛网的情况。结果用密度梯度离心法成功分离获得了高纯度的骨髓MSCs。经骨向诱导后,ALP和矿化结节染色阳性。扫描电镜可观察到骨向诱导后细胞复合在钛网表面有矿化的基质沉积。结论成功建立了大鼠骨髓MSCs体外分离和培养体系,MSCs能够向成骨细胞分化,骨向诱导后细胞复合钛网体外有矿化的基质。