Comparing histological data from different brains: Sources of error and strategies for minimizing them

The recent development of brain atlases with computer graphics templates, and of huge databases of neurohistochemical data on the internet, has forced a systematic re-examination of errors associated with comparing histological features between adjacent sections of the same brain, between brains treated in the same way, and between brains from groups treated in different ways. The long-term goal is to compare as accurately as possible a broad array of data from experimental brains within the framework of reference atlases. Main sources of error, each of which ideally should be measured and minimized, include intrinsic biological variation, linear and nonlinear distortion of histological sections, plane of section differences between each brain, section alignment problems, and sampling errors. These variables are discussed, along with approaches to error estimation and minimization in terms of a specific example—the distribution of neuroendocrine neurons in the rat paraventricular nucleus. Based on the strategy developed here, the main conclusion is that the best long-term solution is a high-resolution 3D computer graphics model of the brain that can be sliced in any plane and used as the framework for quantitative neuroanatomy, databases, knowledge management systems, and structure–function modeling. However, any approach to the automatic annotation of neuroanatomical data—relating its spatial distribution to a reference atlas—should deal systematically with these sources of error, which reduce localization reliability.     

应用HMM和加权距离判别法的真核基因识别程序研究

根据现代科学对基因的认识，应用了隐马尔科夫模型(HMM)的算法，以大量核酸序列为信息来源，通过计算机计算来寻找未知基因的大体位置；再通过基因的固有结构特征及密码子使用的偏向性，使用加权距离判别法来准确地定位基因，以图形及文本的形式输出，从而极大地方便了实验室的研究工作。考虑到基因的许多特征还不为人们所了解，而且不同物种之间基因结构又有一定的差异，所以还开发了程序自学习功能，不断地存储已知的基因，再据此改变一些已有固有数据，以便更好地适应和了解不同生物基因结构的特异性，更加准确地寻找未知基因的位置。     

脂肪来源间充质干细胞对大鼠肝移植的免疫调节作用

目的探讨大鼠脂肪来源间充质干细胞(MSC)对大鼠肝移植术后急性排斥反应的作用。方法分离、培养SD大鼠MSC,体外混合淋巴细胞培养(MLC)体系中,研究MSC对Wistar大鼠T细胞增殖的抑制作用。以SD与Wistar大鼠为供受体建立肝移植模型。随机分为MSC处理组与空白对照组,术后第7天检测肝功能、血清白细胞介素(IL)-2和白细胞介素(IL)-10水平、肝组织病理形态及肝细胞凋亡。结果体外MLC中,Wistar大鼠T细胞增殖明显受抑,抑制率为48.44%。实验组血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、总胆红素(TBIL)、IL-2、IL-10分别为(134.2±45.0)、(162.5±30.5)U/L、(30.6±5.4)μmol/L、(187.35±18.26)、(193.95±37.62)μg/L;对照组上述指标分别为(355.6±54.3)、(296.4±71.2)U/L、(145.7±28.6)μmoL/L、(295.73±57.15)、(75.12±11.23)μg/L,两组差异有统计学意义(P<0.05);病检提示实验组排斥反应较对照组明显减轻;脱氧脲核苷酸缺口末端标记(TUNEL)检测提示实验组肝细胞凋亡程度明显低于对照组(P<0.05)。结论供体来源MSC能明显抑制MLC体系中受体源T细胞的增殖,并能显著减轻大鼠肝移植术后急性排斥反应。     

胸大肌肌皮瓣脂肪液化的相关危险因素探讨

目的探讨胸大肌肌皮瓣术后发生脂肪液化的相关危险因素。方法对1998年5月至2005年12月采用胸大肌肌皮瓣修复口腔癌术后组织缺损的82例中10例术后发生不同程度脂肪液化的病例,进行Logistic回归分析。结果Logistic单因素回归分析结果表明：肥胖、电刀切开皮下组织、皮岛设计低于第7肋、吸烟等因素与胸大肌肌皮瓣术后发生脂肪液化有关;Logistic多因素回归分析结果表明：胸大肌肌皮瓣术后发生脂肪液化与肥胖、电刀切开皮下组织、皮岛设计低于第7肋等因素有关,而与吸烟无关。结论肥胖、电刀切开皮下组织、皮岛设计低于第7肋等因素是胸大肌肌皮瓣术后发生脂肪液化的危险因素。     

Hepatic Disposition Characteristics of Electrically Charged Macromolecules in Rat in Vivo and in the Perfused Liver

The effect of electric charge on the hepatic disposition of macromolecules was studied in the rat. Charged derivatives of dextran (T-70) and bovine serum albumin (BSA), mitomycin C–dextran conjugates (MMC-D), and lactosaminated BSA (Lac-BSA) were employed as model macromolecules. After intravenous injection, cationic macromolecules were rapidly eliminated from plasma because of their extensive hepatic uptake, while anionic and neutral macromolecules were slowly eliminated. Cationic macromolecules were recovered from parenchymal and nonparenchymal hepatic cells at a cellular uptake (per unit cell number) ratio of 1.4–3.2, while that of Lac-BSA was 14. During liver perfusion using a single-pass constant infusion mode, cationic macromolecules were continuously extracted by the liver, with extraction ratios at steady-state (E _ss) ranging between 0.03 and 0.54, whereas anionic and neutral macromolecules were almost completely recovered in the outflow at steady state. The E _ss for cationized BSA (Cat-BSA) and cationic MMC-Dcat were concentration dependent and decreased at low temperatures and in the presence of colchicine and cytochalasin B. The possible participation of the internalization process in the uptake of cationic macromolecules by hepatocytes was suggested.     

Effect of the free radical scavenger MCI-186 on spinal cord reperfusion after transient ischemia in the rabbit

Objective: Paraplegia remains a serious complication of aortic operations. The production of free radicals during reperfusion after transient ischemia is believed to induce secondary spinal neuronal injury, resulting in paraplegia. The aim of the present study was to clarify the protective effect and method of administration of antioxidants on the neurological and histological outcome in the animal model for reperfusion injury after transient spinal cord ischemia. Methods: New Zealand white rabbits underwent surgical exposure of the abdominal aorta that was clamped for 15 minutes to achieve spinal cord ischemia. Group A animals received two 10 mg/kg doses of 3-methyl-l-phenyl-2-pyrazolin-5-one (MCI-186) at the time of release of the aortic clamp and 30 minutes later. In group B, MCI-186, 5 mg/kg, was given three times, at the time of aorta clamp release, 30 minutes and 12 hours later. In group C (control group), one dose of vehicle was administered. Neurological status was assessed using modified Tarlov’s score until 168 hours after operation. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage. Results: Groups A and B animals had better neurological function than group C (p(0.001). In contrast, group C animals exhibited paraplegia or paraparesis with marked neuronal necrosis. The number of surviving neurons within examined sections of the spinal cord was significantly greater in group B than in group C (p(0.001). Conclusion: In a 15-minute ischemia-reperfusion model using rabbits, systemic repetitious administration of MCI-186, a free radical scavenger, was found to have a protective effect on the spinal cord neurons both neurologically and histologically. We postulate that the drug minimizes the delayed neuronal cell death for reperfusion injury after transient ischemia by reducing the free radical molecules. Moreover, it was thought that we could protect delayed neuronal cell death more effectively by administering MCI-18612 hours later.     

慢性乙型肝炎肝郁脾虚证的logistic回归及判别分析

目的归纳慢性乙型肝炎肝郁脾虚证的辨证要点。方法对慢性乙型肝炎肝郁脾虚证、肝郁证、脾虚证的症状及舌、脉进行logistic回归及判别分析。结果肝郁脾虚证logistic回归提取的症状为腹胀、倦怠乏力、腹痛、食欲不振、紧脉、便溏、胁肋疼痛、胁肋不适；判别方程包含的症状则为腹痛、腹胀、倦怠乏力、便溏、黄苔。结论肝郁脾虚证的辨证要点包括胁肋疼痛或不适、腹胀、腹痛、乏力、食欲不振、便溏。利用logistic回归和判别分析归纳本证诊断要点是可行的。     

制作缺血性中风气虚血瘀证大鼠模型的实验研究

目的 探索建立缺血性中风气虚血瘀证大鼠模型的制作方法和评价体系。     

出血性脑梗死危险因素的Logistic回归分析

目的探讨出血性脑梗死的危险因素。方法根据专业知识确定与出血性脑梗死有关的因素,采用非条件Logistic回归确定危险因素。结果大面积梗死灶、使用抗凝剂或溶栓治疗、糖尿病史是出血性脑梗死的独立危险因素,与年龄、高血压史、高血脂关系不大。结论大面积脑梗死、使用抗凝剂或溶栓、糖尿病患者发生梗死后出血的几率增大,及时行影像学检查可以早期发现。