γ线照射对大鼠胃酸分泌及胃泌素释放的影响

本实验观察了大鼠全身照射不同剂量(4～25Gy)及全腹部照射(10Gy)后胃酸分泌的变化并用RIA方法测定照射后胃窦及血清中胃泌素水平.结果表明,全身8～25Gy照射后第3天,腹部10Gy照射后1～6周,胃酸分泌明显抑制.主现表现为胃液中[H~+]分泌的抑制,致使照射后胃液酸度降低.10Gy以上剂量照射使胃泌素释放增加,表现为血清胃泌素明显升高,胃窦胃泌素明显减少,导致照射引起的"低胃酸、高胃泌素血症".这种表现与人的某些萎缩性胃炎或恶性贫血的状况相似.     

Collagen-coated polylactide microspheres as chondrocyte microcarriers

Polylactide (PLA) microspheres were coated with collagen for cell culture and injectable cell carriers. Utilizing a method of emulsion-solvent evaporation, PLA microspheres with diameter ranging from 180 to 280 microm were prepared, followed with aminolysis in hexanediamine/n-propanol solution to introduce free amino groups on their surfaces. After the amino groups were transferred into aldehyde groups by a treatment of glutaraldehyde, collagen type I was covalently coupled via Schiff base formation between the aldehyde groups and the amino groups on collagen molecules. Meanwhile, physically entangled collagen molecules were retained following a grafting-coating protocol to yield microspheres coated with larger amount of collagen. Aminolysis resulted in weight loss of the microspheres following a linear relationship with the aminolysis time. The NH2 and collagen contents existed on the microsphere surface were quantitatively determined by ninhydrin and hydroproline (Hyp) analyses, respectively. Larger amount of collagen was immobilized on the microspheres with higher content of NH2. In vitro chondrocyte culture revealed that the cells could attach, proliferate and spread on these PLA microspheres, in particular on the ones having higher content of collagen. These results show that the collagen-coated PLA microspheres are promising candidate as cell microcarriers.     

Identification of 16 novel mutations in the argininosuccinate synthetase gene and genotype-phenotype correlation in 38 classical citrullinemia patients

Classical citrullinemia (CTLN1), a rare autosomal recessive disorder, is caused by mutations of the argininosuccinate synthetase (ASS) gene, localized on chromosome 9q34.1. ASS functions as a rate-limiting enzyme in the urea cycle. Previously, we identified 32 mutations in the ASS gene of CTLN1 patients mainly in Japan and the United States, and to date 34 different mutations have been described in 50 families worldwide. In the present study, we report ASS mutations detected in 35 additional CTLN1 families from 11 countries. By analyzing the entire coding sequence and the intron-exon boundaries of the ASS gene using RT-PCR and/or genomic DNA-PCR, we have identified 16 novel mutations (two different 1-bp deletions, a 67-bp insertion, and 13 missense) and have detected 12 known mutations. Altogether, 50 different mutations (seven deletion, three splice site, one duplication, two nonsense, and 37 missense) in 85 CTLN1 families were identified. On the basis of primary sequence comparisons with the crystal structure of E. coli ASS protein, it may be concluded that any of the 37 missense mutations found at 30 different positions led to structural and functional impairments of the human ASS protein. It has been found that three mutations are particularly frequent: IVS6-2A>G in 23 families (Japan: 20 and Korea: three), G390R in 18 families (Turkey: six, U.S.: five, Spain: three, Israel: one, Austria: one, Canada: one, and Bolivia: one), and R304W in 10 families (Japan: nine and Turkey: one). Most mutations of the ASS gene are "private" and are distributed throughout the gene, except for exons 5 and 12-14. It seems that the clinical course of the patients with truncated mutations or the G390R mutation is early-onset/severe. The phenotype of the patients with certain missense mutations (G362V or W179R) is more late-onset/mild. Eight patients with R86H, A118T, R265H, or K310R mutations were adult/late-onset and four of them showed severe symptoms during pregnancy or postpartum. However, it is still difficult to prove the genotype-phenotype correlation, because many patients were compound heterozygotes (with two different mutations), lived in different environments at the time of diagnosis, and/or had several treatment regimes or various knowledge of the disease.     

大鼠前庭神经核群向腰髓投射特征——BDA法逆行研究

目的　研究大鼠前庭神经核群向脊髓的投射纤维特征。方法　在 7例SD大鼠采用结合生物素的葡聚糖胺(BDA)逆行法观察大鼠前庭核群向脊髓的投射。结果　除前庭神经上核 (SVN)外的其余各前庭核均有向大鼠腰髓的投射 ,单侧注射的实验动物中 ,前庭神经内侧核 (MVN)、外侧核 (LVN)和降核 (DVN)的标记神经元可见于双侧 ,其中MVN和LVN的标记神经元以注射同侧占优势 ,而DVN标记神经元两侧数量基本一致。结论　大鼠前庭脊髓尾侧束发出纤维投向脊髓腰段     

大鼠运动皮层投射神经元与Parvalbumin免疫阳性神经纤维终末的关系──免疫荧光、Confocal显微镜观察

Parvalburnin是细胞内一种钙结合蛋白。同时又可作为中枢神经系统内与GABA共存的神经元亚群的特异标记物，主要标记篮状及苔烛细胞。用PAP方谈染色可见大鼠Parvalbumin免疫阳性神经终末在运动皮层锥体神经元胞体周围形成包篮现象，但因该方法的局限性．较难明确二者的关系。为进一步了解Parvalbumin阳性终未在锥体神经元脑体、树突与轴突整体上的分布状况以及运幼皮层内不同传出神经元是否均接受同样的支配，本实验利用FastBlue送行标记、固定脑片细胞内注入LueiferYellow结合免疫荧光、Confocal显微镜观察，研究运动皮层内皮质丘脑（束旁核）、皮质效状体及皮质脊髓三种投射神经元与Parvalbumin阳性终末的关系。通过1．μ连续扫描图像的分析及立体对观察，Parvalbumin阳性终末清晰可见，与LuciferYellow标记的锥体细胞的关系也容易辨别．在三种投射神经元胞体上均可见Parvalbumin阳性终末包绕，形成明显包篮现象，但三种神经元上的终末数未见明显区别·阳性终未还分布于近端树突上，距胞体越远越稀疏：但在距脑体50μm以上的顶树突、30μm以上的基树突及其二、三级分枝的远端树突上仍偶有终末分布．此外，三种神经元轴突起始段上也有少量终末接触，但未形成明显的cartridge现象．这一结果揭示，Parvalb     

Determination of optimal cryoprotectants and procedures for their addition and removal from human spermatozoa

The objective was to test the hypothesis that the optimal cryoprotective agent for cryopreservation of human spermatozoa would be a solute for which cells have the highest plasma membrane permeability, resulting in the least amount of volume excursion during its addition and removal. To test this hypothesis, theoretical simulations were performed using membrane permeability coefficients to predict optimal procedures for the addition and removal of a cryoprotectant. Simulations were performed using data from four different cryoprotectants: (i) glycerol, (ii) dimethyl sulphoxide, (iii) propylene glycol and (iv) ethylene glycol. Thermodynamic formulations were applied to determine approaches for the addition and removal of 1 M and 2 M final concentrations of cryoprotectant, allowing the spermatozoa to maintain a cell volume within their osmotic tolerance limits. Based on these data, ethylene glycol was predicted to be optimal for minimizing volume excursions among the solutes evaluated. These predictions were then experimentally tested using glycerol as the control cryoprotectant and ethylene glycol as the experimental cryoprotectant. The results indicate that there was a higher (P < 0.05) recovery of motile spermatozoa after cryopreservation when using 1 M ethylene glycol than with 1 M glycerol, supporting the hypothesis that use of the cryoprotectant for which the cell has the highest permeability will result in higher cell survival.      

Molecular genetic characterization of XRCC4 function

XRCC4 is a generally expressed protein of 334 amino acids that is involved in the repair of DNA double-strand breaks and in V(D)J recombination, but its function is unknown. In this study, we have used a mutational approach and the yeast two-hybrid method to perform an initial characterization of this protein. We show that the XRCC4 protein is located in the nucleus. We also demonstrate that several potential phosphorylation sites are not required for XRCC4 function in a transient V(D)J recombination assay. In addition, we show that XRCC4 forms a homodimer in vivo with the homodimerization domain being located within amino acids 115-204. Finally, we define a core domain of XRCC4 that functions in V(D)J recombination and comprises amino acids 18-204. Potential functions of XRCC4 are discussed.      

痢疾杆菌免疫小鼠的GALT中T淋巴细胞亚群的应答状态

以鼠伤寒杆菌Ｇ３０株为对照，应用间接免疫荧光法检测了痢疾杆菌福氏２ａ经口服及腹腔免疫后，小鼠派伊尔氏（ＰＰ）节结、肠系膜淋巴结（ＭＬＮ）及脾脏（ＳＰｔ）中Ｌ３Ｔ４～＋、Ｌｙｔ２～＋Ｔ细胞亚群的变化；并以ＭＴＴ比色法测定了ＣｏｎＡ诱导的淋巴细胞增殖反应。实验发现：无论是口服还是腹腔途径，这两种细菌都诱导出基本相似的Ｔ淋巴细胞反应，即Ｌ３Ｔ４亚群在ＰＰ及ＭＬＮ中均有显著升高，而Ｌｙｔ２亚群均无明显变化；口服途径仅ＰＰ淋巴细胞的增殖反应有明显升高，腹腔途径主要为ＭＬＮ出现淋巴细胞显著的增殖反应。提示：在痢疾菌感染免疫中以Ｌ３Ｔ４亚群起主要作用；ＰＰ作为粘膜免疫的诱导部位；经口途径主要诱导肠道局部淋巴细胞的免疫应答，经腹腔途径虽能诱导多部位免疫应答但有否抗粘膜感染保护作用尚待研究。     

扫描电镜图像处理系统及其在细胞超微结构定量计算中的应用

本文介绍一种具有较高性能价格比的生物医学电镜图像处理系统,该系统以IBM PC/XT,AT或386计算机为主机,图像接口板直接插入机内扩展槽。应用软件可对生物医学图像作图像处理和定量计算。作者通过对人膈腹膜超微结构进行定量分析,为腹水的治疗和腹膜透析(CAPD)等临床医学研究,提供了形态学定量资料。     

心电信号预测冠心病的粗糙集方法

应用粗糙集理论对心电图波形所蕴涵的大量信息进行处理，目的是评价心电信号实测指标与冠心病的关系。通过对心电图导联I中采集的心电信号进行属性约简，降低决策表的冗余性，提取用于判别冠心病的重要属性和诊断规则。实例分析表明，粗糙集理论应用于心电信号分析，可得到清晰简明的诊断规则，有助于冠心病的临床诊断。