Expression, purification and molecular modeling of recombinant fibrinogenase [IV], a metalloproteinase from Deinakistrodon acutus venom.

A novel metalloproteinase, recombinant fibrinogenase IV (rFIV(a)), was expressed and purified from Deinakistrodon acutus venom. It was a single chain protein with an apparent molecular weight 27 kDa and an isoeletric point of pH 7.1. RFIV(a) cleaved preferentially the Aalpha-chain and also cleaved Bbeta, gamma-chains of fibrinogen when the incubation time was prolonged. The proteolytic activity was inhibited by EDTA, l-cysteine, and DTT, indicating rFIV(a) was a metalloproteinase requiring disulfide bonds for its activity. It kept above 85% of the initial activity from pH 4.5-11, showed an equal maximum activity at the temperature range from 30 to 50 degrees C, and was inactivated by Zn2+, Cu2+ and Cd2+. Homology modeling of rFIV(a) showed that two highly conserved disulfide bonds (Cys159-Cys164 and Cys117-Cys197) was maintained from its structure, and it exhibited the characteristic conserved motif H142E143XXH146XXGXXH152, whose three histidine residues were involved in binding of the catalytically essential zinc ion. This work demonstrates the expression, purification and characterization of recombinant fibrinogenase IV, which belongs to class P-I metalloproteinase from D. acutus venom.     

Proposal of a modified Child-Turcotte-Pugh scoring system and comparison with the model for end-stage liver disease for outcome prediction in patients with cirrhosis.

The model for end-stage liver disease (MELD) has a better predictive accuracy for survival than the Child-Turcotte-Pugh (CTP) system and has been the primary reference for organ allocation in liver transplantation. The CTP system, with a score range of 5-15, has a ceiling effect that may compromise its predictive power. In this study, we proposed a refined CTP scoring method and investigated its predictive ability. An additional point was given to patients with serum albumin < 2.3 g/dL, bilirubin > 8 mg/dL or prothrombin time prolongation > 11 seconds. The modified CTP system, containing class D, was compared to the MELD and original CTP system in 436 patients. There was a significant correlation between the MELD and modified CTP score (rho = 0.59, P< 0.001). Using mortality as the endpoint, the area under receiver operating characteristic curve for modified CTP system was 0.895 compared with 0.872 for MELD (P = 0.450) and 0.809 for original CTP system (P < 0.001) at 3 months; the area was 0.890, 0.837 and 0.756, respectively (P = 0.051 and < 0.001, respectively) at 6 months. The risk ratio per unit increase for the modified CTP score was 2.7 and 3.08 at 3 and 6 months respectively (P < 0.001). In conclusion, the modified CTP system can be proposed as an alternative prognostic model for cirrhotic patients. By extending the score range according to the influence of the laboratory-derived variables, the modified CTP system has a better performance than the original system and is as efficient as the MELD for outcome prediction.     

兔视网膜方向选择性神经节细胞树突的独特分枝模式及其生理意义

本实验研究了兔视网膜中的方向选择性神经节细胞 (direction selective retinal ganglion cells,DS cells)树突野的分枝模式。测量了视网膜中方向选择性神经节细胞和作为经典分枝模式神经元代表的α神经节细胞的树突直径。发现 ,方向选择性神经节细胞的树突在分枝后直径达到 0 .5 μm,进一步分枝树突直径仍保持在 0 .5 μm左右 ,这样 ,在方向选择性神经节细胞树突野中大多数树突直径在 0 .5μm左右。而作为经典分枝模式神经元代表的α神经元的树突每次分枝后都逐级变细 ,最终直径达到 0 .5μm左右 ,这样 ,α神经节细胞的树突直径大部分都大于 0 .5μm。我们应用程序“NEU RON”对在两种神经元模型中 ,抑制点落于兴奋点与胞体之间 (proximal)和抑制点不落于兴奋点与胞体之间 (distal)这两种情况进行模拟。我们发现 ,当抑制点不落于兴奋点与胞体之间时 ,在方向选择性神经节细胞的树突分枝模型中 ,抑制效果更强。那么 ,将使得方向选择性神经节细胞对抑制点落于兴奋点和胞体之间的要求变得不是那么迫切。所以 ,方向选择性神经节细胞的这种独特分枝模式 ,也许可以避免或至少减轻其在发育中可能会产生的连线的复杂性。并且 ,我们对得出的结论进行了电路分析 ,对方向选择性神经节细胞这种独特的分枝模式具有的?     

局灶脑缺血恢复期半影区小胶质细胞可塑性变化和bFGF表达规律探讨

目的 观察Wistar大鼠大脑中动脉永久性闭塞后不同时段，缺血半影区小胶质细胞和神经元形态学变化及bFGF在皮层和海马的表达规律。方法 将雄性Wistar大鼠48只，随机分为假手术对照组和永久性局灶性脑缺血组，后者再根据缺血时间不同分5个亚组。假手术组：仅暴露大脑中动脉，2h后断头取脑。永久性局灶性脑缺血组：建立大鼠大脑中动脉闭塞模型，分别于缺血后3d、7d、14d、28d、42d断头取脑，行HE和免疫组化染色。观察梗死灶周围半影区的小胶质细胞和神经元的形态学变化和bFGF在皮层及海马部位的表达规律。结果 HE染色可见脑缺血3d时半影区有少量小胶质细胞出现，14d小胶质细胞增多达高峰，42d趋于稳定。脑缺血3d梗死灶周围皮质神经元和胶质细胞开始表达bFGF，7d表达增强，14d达高峰，28d表达开始减弱，42d仍有一定表达，bFGF在海马的表达也有相同规律。结论 小胶质细胞的肥大和增生性变化以及bFGF的表达，不仅发生于脑缺血早期，晚期仍显示持续性变化，表明小胶质细胞活动以及bFGF的表达贯穿于脑缺血的整个病理过程。     

全雄激素阻断治疗晚期前列腺癌

为了评价全雄激素阻断治疗晚期前列腺癌的疗效，采用双侧睾丸切除、Ｆｌｕｔａｍｉｄｅ和Ｆｉｎａｓｔｅｒｉｄ联合治疗Ｄ２期前列腺癌病人５例。随访１５～２０个月，结果ＰＳＡ均正常，前列腺体积缩小６１．２％～６９．３％，有显著性差异（Ｐ＜０．０１），骨转移灶缩小、部分消失，积水肾脏完全恢复正常，所有病人治疗后全部有效。表明全雄激素阻断对晚期前列腺癌有良好的治疗效果。提出在三个层次上阻断雄激素治疗晚期前列腺癌的策略。     

动脉分支处的红细胞流变学研究与小动脉端侧吻合

为了探讨动脉分支处及小动脉端侧吻合处的血液流动方式，采用微循环电视显微镜成像技术，活体观察大鼠肠系膜微动脉分支区域血液流动方式和红细胞流变行为，研究动脉血流方向的改变对血流方式的影响。实验中观察到，在形态各异的大鼠肠系膜微动脉分支区域血液流态为稳定层流；红细胞通过不规则变形能很好地适应血管腔不同的几何形态，以保持血液流态的稳定。结果表明，微小动脉血流方向的改变未能在分支区域导致湍流发生，小动脉端侧吻合只是人为增加了侧支循环，同样不会导致血流紊乱和增加血栓形成的危险     

应把防治医患纠纷作为临床医德教育的重要内容

不断强化医务人员的服务意识是消除医患纠纷的首要条件,认真培养敬业精神是避免医患纠纷的根本途径;提高道德境界是避免医患纠纷的决定因素.     

Effects of decentralization on the levels of GAP-43 and p38 (synaptophysin) in sympathetic adrenergic neurons: a semi-quantitative study using immunofluorescence and confocal laser scanning microscopy

The distribution of GAP-43 in superior cervical ganglion (SCG) and iris were studied in normal animals and following decentralization using immunofluorescence and confocal laser scanning microscopy (CLSM). GAP-43-like immunoreactivity (LI) was compared with p38 (synaptophysin)-LI, and tyrosin hydroxylase (TH)-LI. In the control SCG, GAP-43-LI and p38-LI were mainly localized in nerve terminals around the principal neurons. The neuronal perikarya were negative for GAP-43, but positive for p38 in a perinuclear zone, as well as positive for TH. SIF cells (Small Intensely Fluorescent cells, ganglionic interneurons) were positive for GAP-43, TH and p38. One day after decentralization, GAP-43-LI and p38-LI in nerve terminals around principal neurons had disappeared. Some of the principal neurons showed a weak GAP-43-immunoreactivity. Three days post-decentralization, GAP-43- and p38-positive nerve terminals around the neurons had reappeared in considerable numbers and the intra-ganglionic nerve bundles were positive for both antibodies. In the control irides, GAP-43-LI and p38-LI were distributed in a varicose pattern in the nerve bundles, around blood vessels and in the network of terminals. Double labelling studies showed that GAP-43-LI was colocalized with TH-LI and p38-LI. The network of terminals in the dilator plate of the irides was quantified by measuring the fluorescence intensity of randomly selected areas, using CLSM. Three days after decentralization the intensity of GAP-43-LI and p38-LI had significantly increased. TH-LI had decreased 8 days after decentralization. The results indicate that GAP-43-LI and p38-LI are normally present in the nerve fibers and terminals of both pre- and post-ganglionic neurons in adult rats. The expression of GAP-43-LI and p38-LI in post-ganglionic neurons is preganglionically regulated, as indicated by the increased expression after decentralization. The expression of p38 in these neurons is probably regulated via mechanisms that are separate from those which regulate GAP-43, since it showed a different time course than that of GAP-43-LI.     

Active oxygen radicals produced by leukocytes of malignant lymphoma.

The electron spin resonance (ESR) spectra of active oxygen radicals produced during the respiratory burst of PMA-stimulated leukocytes and oxygen consumption are studied by ESR spin trapping and spin probe oxymetry for 31 times in 17 cases of malignant lymphoma. The results showed that the spectra produced from PMA-stimulated patients' leukocytes were predominantly spin adducts of DMPO-hydroxyl radicals (DMPO-OH). The decrease in oxygen consumption during respiratory burst suggested that respiratory burst function was inhibited. Kinetic observations of patient condition showed that respiratory burst and oxygen consumption were improved and even approached normal, when the patient was in remission or the condition was ameliorated. This paper is the first of its type and helps clarify the mechanism of malignant proliferation and metastasis.

     

Microvascular corrosion casting of normal tissue, transitional mucosa and adenocarcinoma in the human colon.

The microcirculatory architecture of normal tissue, transitional mucosa and adenocarcinoma of the human colon was investigated with microvascular corrosion casting (MVCC) combined with scanning electron microscopy (SEM). The study showed that the capillaries within the normal mucosa were arranged in a regular hexagonal pattern around the mucosal glands and that the microvessels of transitional mucosa mostly had lost the typical hexagonal pattern and become slightly wider in diameter. The microvessels in the tumor periphery were increased in number and disorganized, and presented large variation in morphology with claw-like formations, widened sinuses, diverticula and appendixoid patterns. Microvessels were lacking in the central areas of tumors. These morphological alterations may serve as additional indicators of tumor development.