T—2毒素致DNA损伤的单细胞电泳观察

应用单细胞凝胶电泳法（ＳＣＧＥ），测定Ｔ－２毒素引起ｖｅｒｏ细胞的ＤＮＡ损伤。结果显示，Ｔ－２毒素在４００～８００ｎｇ／ｍｌ浓度范围内能够引起ＤＮＡ损伤并有明显的剂量反应关系。对于该项实验在大骨节病研究中的意义做了扼要讨论     

HBcAg DNA疫苗诱导小鼠（H—2^b）特异性细胞和体液免疫应答

目的 观察ＨＢｃＡｇ ＤＮＡ疫苗（ｐＪＷ４３０３／ＨＢｃ）免疫Ｃ５７ＢＬ／６小鼠（Ｈ－２＾ｂ）的特异性细胞和体液免疫应答。方法 基因枪和肌肉注射两种方法接种ＤＮＡ疫苗;ＥＬＩＳＡ法检测小鼠血清抗－ＨＢｃ（ＩｇＧ）及ＩｇＧ亚类（ＩｇＧ１,ＩｇＧ２ａ）;＾５１铬释放法检测小鼠脾细胞ＨＢｃＡｇ特异性ＣＴＬ活性。结果 该ＤＮＡ疫苗体外可表达ＨＢｃＡｇ;小鼠经基因枪或肌肉注射接种该疫苗后血清抗－ＨＢｃ滴度分     

H_2O_2致小鼠淋巴细胞DNA的损伤及修复

目的　应用单细胞电泳检测 (SCGE)过氧化氢 (H2 O2 )致小鼠淋巴细胞 DNA损伤及其修复。方法　标准 SCGE条件下荧光显微镜观察。结果　 H2 O2 不同浓度 80、16 0和 32 0μmol/ L ,3个组 H2 O2 浓度均可致小鼠淋巴细胞 DNA损伤 ,较低剂量即可造成细胞拖尾 ,可逆性损伤在 6 0 m in内可获得明显修复。结论　单细胞电泳可快速灵敏地检测氧化损伤 ,也可能用于流行病学研究。     

乙型肝炎病毒核心区DNA疫苗接种后H-2d小鼠的特异性免疫应答

目的观察乙型肝炎病毒（ＨＢＶ）核心区ＤＮＡ疫苗接种后ＢＡＬＢ／ｃ（－２ｄ）小鼠的特异性免疫应答。方法构建ＨＢＶ核心区ＤＮＡ疫苗（ＰＪＷ４３０３／ＨＢｃ）;用基因枪法和肌肉注射祛将该ＤＮＡ疫苗接种ＢＡＬＢ／ｃ小鼠;ＥＬＩＳＡ法检测小鼠血清抗－ＨＢＣ（ＩｇＧ）及ＩｇＧ亚类（ＩｇＧ１,ＩｇＧ２ａ）;５１铬释放法检测小鼠脾细胞ＨＢｃＡｇ特异性ＣＴＬ活性。结果该ＤＮＡ疫苗在体外转染细胞中可良好表达ＨＢｃＡｇ。血清抗－ＨＢｃ终点滴度在ＤＮＡ疫苗基因枪组和肌肉注射接种组小鼠分别为１：３２８０５０和１：１０９３５０．两组小鼠的抗－ＨＢｃＩｇＧ亚类均以ＩｇＧ２ａ略占优势。两组小鼠的ＨＢＣＡｔｈｅ异性ＣＴＬ杀伤活性分别达到５１．１％和５５．２％。结论ＨＢＶ核心区ＤＮＡ疫苗在小鼠实验中具有良好的细胞免疫和体液免疫原性。     

单细胞凝胶电泳技术分析过氧化氢对大鼠外周血淋巴细胞DNA的损伤作用

目的观察不同浓度过氧化氢（２５－２００μｍｏｌ／Ｌ）分别作用于正常大鼠外周血淋巴细胞不同时间（５ｍｉｎ和２０ｍｉｎ）后细胞ＤＮＡ的损伤情况。方法利用快速、灵敏的检测细胞ＤＮＡ损伤的单细胞凝胶电泳（ＳＣＧ）技术结合激光扫描共聚焦显微镜,以“彗星样”淋巴细胞出现率（计数一定量细胞其中彗星样细胞所占的比例）、总彗星长度（“彗星”电泳方向上的最大长度,即尾长）和尾距（尾部ＤＮＡ占总ＤＮＡ的百分比与头尾部中     

表皮生长因子对腹膜间皮细胞增殖的影响

为探讨表皮生长因子（ＥＧＦ）对腹膜间皮细胞增殖的影响，以了解其在损伤腹膜修复中的作用及其机制，建立了人腹膜间皮细胞（ＨＭＣ）培养体系。采用真空负压ＡＢＣ免疫组化法分析了ＨＭＣ表面表皮生长因子受体（ＥＧＦ－Ｒ）的表达，并以３Ｈ－胸腺嘧啶核苷（３Ｈ－ＴｄＲ）掺入法对６例ＨＭＣ在不同培养时间和不同剂量ＥＧＦ作用下的细胞增殖程度进行了检测。结果表明，ＨＭＣ表面有ＥＧＦ－Ｒ存在，ＥＧＦ能促进ＨＭＣ增殖，当ＨＭＣ在含２０μｇ／ＬＥＧＦ的培养基中生长时，其３Ｈ－ＴｄＲ掺入量与对照组比较明显增加（Ｐ＜０．０１），而ＥＧＦ浓度５０μｇ／Ｌ时，ＨＭＣ增殖指数最大（ＰＩ＝８．１６），ＨＭＣ的增殖程度和ＥＧＦ呈时间与剂量依赖关系。提示，ＥＧＦ可能通过与ＨＭＣ表面的ＥＧＦ－Ｒ结合，促进细胞内的ＤＮＡ合成，加速细胞的增殖，对损伤腹膜的修复起重要作用。     

心力衰竭时内皮细胞损伤和功能变化的临床研究

为了解血管内皮细胞（ＶＥＣ）损伤及其功能变化与充血性心力衰竭（ＣＨＦ）的关系，我们以循环内皮细胞（ＣＥＣ）作为ＶＥＣ损伤的指示物，以血浆内皮素（ＥＴ）、血管紧张素转换酶（ＡＣＥ）和前列环素（ＰＧＩ２）反映ＶＥＣ功能改变，对５４例ＣＨＦ患者与３０例正常人进行对比研究。结果表明：ＣＨＦ病人ＣＥＣ数量、ＥＴ浓度和ＡＣＥ活性明显增高，并与病情严重程度一致，轻度ＣＨＦ者，ＰＧＩ２增高，严重ＣＨＦ者ＰＧＩ２较正常降低，ＣＥＣ数与血ＥＴ和ＡＣＥ呈显著正相关，提示ＣＨＦ病人ＶＥＣ损伤，致其分泌的内皮源性舒张因子与收缩因子失平衡，参与了ＣＨＦ的病理过程。     

高血压病患者动脉平滑肌细胞NO的变化及其与发病的关系

为探讨高血压病（ＥＨ）患者一氧化氮（ＮＯ）浓度变化特点与高血压病发病的特点，本研究以复合胶元酶法分离培养ＥＨ患者和血压正常者（ＮＴ）离体动脉平滑肌细胞（ＶＳＭＣ）检测细胞培养液的ＮＯ含量和ＶＳＭＣ的一氧化氮含量（ＮＯＳ）的活性，观察ＥＨ患者动脉ＶＳＭＣ分泌ＮＯ的特点，结果显示：（１）ＥＨ组ＶＳＭＣ的ＮＯ含量和ＮＯＳ活性均显著于低于ＮＴ组（Ｐ〈０．０１）；（２）ＥＨ患者和ＮＴＶＳＭＣ的ＮＯ含量和ＮＳ     

肝损伤小鼠肝组织氧化／抗氧化平衡的变化及其与TXA2／PGI2？…

目的：探讨氧自由基（ＯＦＲ）及ＴＸＡ２－ＰＧＩ２在实验性肝损伤中的作用。方法：检测肝损伤小鼠肝组织过氧化脂质（ＬＰＯ）、超氧化物歧化酶（ＳＯＤ）含量以及血浆ＴＸＡ和ＰＧＩ２浓度。结果：与对照组比较肝损伤小鼠ＬＰＯ明显升高、ＳＯＤ明显降低，当归可逆转ＬＰＯ和ＳＯＤ的变化；肝损伤小鼠血浆ＴＸＢ２高于对照组，其浓度与肝细胞ＬＰＯ含量呈正相关（ｒ＝０．９５，Ｐ〈０．０１）。结论：ＯＦＲ与ＴＸＡ２／ＰＧＩ２     

DNA聚合酶α反义寡核苷酸抑制人胃癌细胞生长

目的研究ＤＮＡ聚合酶α（ＤＮＡｐｏｌｙｍｅｒａｓｅα，ＤＮＡ＿ｐｏｌα）特异的寡聚脱氧核苷酸（ｏｌｉｇｏｄｅｏｘｙｎｕｃｌｅｏｔｉｄｅ，ＯＤＮ）对人胃癌细胞生长的抑制作用。方法设计并合成与ｐｏｌα催化亚基ｍＲＮＡ翻译起始区和功能Ⅰ区互补的正义、反义ＯＤＮ（ＳＯＤＮ，ＡＳＯＤＮ），作用于人胃癌细胞系ＭＧＣ＿８０３，ＳＧＣ＿７９０１及正常对照人脐静脉曲皮细胞（ＨＵＶＥＣ），体外培养９６ｈ，ＭＴＴ比色法测定细胞存活状态，流式细胞仪分析ＤＮＡ含量。结果只有互补于ｐｏｌα翻译起始区的１８ｍｅｒＡＳＯＤＮ＿１可显著抑制人胃癌细胞的生长，并使胃癌细胞的ＤＮＡ指数值明显降低，半数抑制浓度约为１００μｇ／ｍｌ，培养４８ｈ后作用显著；而ＨＵＶＥＣ的生长未受明显干扰。结论ＤＮＡ＿ｐｏｌα催化亚基ｍＲＮＡ可作为构建抗肿瘤反义寡核苷酸的靶核酶，为恶性肿瘤的特异性治疗带来突破性进展。     

Classification and characterization of hereditary types 2A, 2B, 2C, 2D, 2E, 2M, 2N, and 2U (unclassifiable) von Willebrand disease.

All variants of type 2 von Willebrand disease (VWD) patients, except 2N, show a defective von Willebrand factor (VWF) protein (on cross immunoelectrophoresis or multimeric analysis), decreased ratios for VWF:RCo/Ag and VWF:CB/Ag and prolonged bleeding time. The bleeding time is normal and FVIII:C levels are clearly lower than VWF:Ag in type 2N VWD. High resolution multimeric analysis of VWF in plasma demonstrates that proteolysis of VWF is increased in type 2A and 2B VWD with increased triplet structure of each visuable band (not present in types 2M and 2U), and that proteolysis of VWF is minimal in type 2C, 2D, and 2E variants that show aberrant multimeric structure of individual oligomers. VWD 2B differs from 2A by normal VWF in platelets, and increased ristocetine-induced platelet aggregation (RIPA). RIPA, which very likely reflects the VWF content of platelets, is normal in mild, decreased in moderate, and absent in severe type 2A VWD. RIPA is decreased or absent in 2M, 2U, 2C, and 2D, variable in 2E, and normal in 2N. VWD 2M is usually mild and characterized by decreased VWF:RCo and RIPA, a normal or near normal VWF multimeric pattern in a low resolution agarose gel. VWD 2A-like or unclassifiable (2U) is distinct from 2A and 2B and typically featured by low VWF:RCo and RIPA with the relative lack of high large VWF multimers. VWD type 2C is recessive and shows a characteristic multimeric pattern with a lack of high molecular weight multimers, the presence of one single-banded multimers instead of triplets caused by homozygosity or double hereozygosity for a mutation in the multimerization part of VWF gene. Autosomal dominant type 2D is rare and characterized by the lack of high molecular weight multimers and the presence of a characteristic intervening subband between individual oligimers due to mutation in the dimerization part of the VWF gene. In VWD type 2E, the large VWF multimers are missing and the pattern of the individual multimers shows only one clearly identifiable band, and there is no intervening band and no marked increase in the smallest oligomer. 2E appears to be less well defined, is usually autosomal dominant, and accounts for about one third of patients with 2A in a large cohort of VWD patients.     

Structure-function of Hb Marseille-Long Island [alpha 2 beta 2 N-methionyl-2(NA2) His----Pro

Suspensions of red cells containing Hb Marseille-Long Island showed decreased oxygen affinity and low interaction with 2,3-diphosphoglycerate. Oxygen equilibrium studies of the purified component confirmed these abnormalities. Oxidation rate measurements of carbonmonoxy-Hb Marseille and carbonmonoxy-Hb A by ferricyanide showed an increased rate for the former, suggesting an increased dissociation constant for carbon monoxide. Nuclear Magnetic Resonance spectra in the high field region revealed small changes in the proximal region of the heme pocket. These results indicated that the mutation causes a perturbation at a distance from the mutation site.     

Different RBC aggregating properties of the Aalpha2Bbeta2gammaA2 and Aalpha2Bbeta2gammaAgamma' subpopulations of human fibrinogen

Human fibrinogen (TF) has been separated into two fractions: F1 - homodimers with respect to the gamma chain, and F2 - heterodimers composed of gammaA and gamma' polypeptides. Their rouleaux-inducing properties were as follows: (1) both, at the same concentration of 0.8%, were less effective than TF; (2) F1 produced larger rouleaux even under static conditions of a hemocytometer where F2 was silent; (3) F2 induced the process when a suspension was gently sheared between microscopic slides. Since the synthetic peptide gamma'(414-427) inhibited the rouleau formation in a mixture with F2, the C-terminal amino acids of the gamma' polypeptide probably bind the molecule to the cell. The inhibition was feebly visible in the native ratio of F1/F2, implicating a compensatory effect of F1.     

Identification of SH2B2beta as an inhibitor for SH2B1- and SH2B2alpha-promoted Janus kinase-2 activation and insulin signaling

The SH2B family has three members (SH2B1, SH2B2, and SH2B3) that contain conserved dimerization (DD), pleckstrin homology, and SH2 domains. The DD domain mediates the formation of homo- and heterodimers between members of the SH2B family. The SH2 domain of SH2B1 (previously named SH2-B) or SH2B2 (previously named APS) binds to phosphorylated tyrosines in a variety of tyrosine kinases, including Janus kinase-2 (JAK2) and the insulin receptor, thereby promoting the activation of JAK2 or the insulin receptor, respectively. JAK2 binds to various members of the cytokine receptor family, including receptors for GH and leptin, to mediate cytokine responses. In mice, SH2B1 regulates energy and glucose homeostasis by enhancing leptin and insulin sensitivity. In this work, we identify SH2B2beta as a new isoform of SH2B2 (designated as SH2B2alpha) derived from the SH2B2 gene by alternative mRNA splicing. SH2B2beta has a DD and pleckstrin homology domain but lacks a SH2 domain. SH2B2beta bound to both SH2B1 and SH2B2alpha, as demonstrated by both the interaction of glutathione S-transferase-SH2B2beta fusion protein with SH2B1 or SH2B2alpha in vitro and coimmunoprecipitation of SH2B2beta with SH2B1 or SH2B2alpha in intact cells. SH2B2beta markedly attenuated the ability of SH2B1 to promote JAK2 activation and subsequent tyrosine phosphorylation of insulin receptor substrate-1 by JAK2. SH2B2beta also significantly inhibited SH2B1- or SH2B2alpha-promoted insulin signaling, including insulin-stimulated tyrosine phosphorylation of insulin receptor substrate-1. These data suggest that SH2B2beta is an endogenous inhibitor of SH2B1 and/or SH2B2alpha, negatively regulating insulin signaling and/or JAK2-mediated cellular responses.     

Influence of Mixed Na2O/K2O on Chemical Durability and Spectral Properties of P2O5-Al2O3-BaO-K2O-Na2O-Nd2O3 Phosphate Glasses

A series of 56P₂O₅-7.5Al₂O₃-5.9BaO-(28.56-x)K₂O-xNa₂O-1.51Nd₂O₃ phosphate glasses with different Na/(Na+K) ratios, which were specially designed for high-power laser application, were prepared by a high-temperature melting method. Except for the density, refractive index, glass transition temperature, and DC conductivity, the chemical durability and spectral properties, as emphasized by high-power and high-energy laser material, were further measured and analyzed. Regarding the chemical durability, the dissolution rates of these glasses do not show an evident mixed alkali effect with increasing the Na/(Na+K) ratio, although the effect is obvious for the glass transition temperature and DC conductivity. To better understand the nature of the dissolution mechanism, the ionic release concentrations of every element are determined. Both Na and K undergo ion exchange, but the ion exchange rate of K is much larger than that of Na. In terms of the spectral properties, the J–O parameters, emission cross-section, radiation lifetime, fluorescence lifetime, effective bandwidth, fluorescence branching ratio, and quantum efficiency are determined from absorption and emission spectra. The trend of Ω₂ deviating from linearity indicates that the coordination environment symmetry of Nd³⁺ ions and the covalence of Nd-O also present an evident mixed alkali effect. The most important finding is that the emission cross-section and fluorescence lifetime of Nd³⁺ ions at 1053 nm were not affected by the change in the Na/K ratio. According to the above experimental results, the optimized value of the Na/K ratio was determined, based on which the 56P₂O₅-7.5Al₂O₃-5.9BaO-(28.56-x)K₂O-xNa₂O-1.51Nd₂O₃ glass maintains a high emission cross-section with good chemical durability.