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101.
102.
大白鼠游泳输出功测定仪的研制和疲劳方程Y=A+B/T的建立 总被引:1,自引:0,他引:1
研制了可以直接连续测量大鼠游泳输出功率的仪器,建立了一个理想的动物模型,通过分析对功率曲线进行函数拟合,得出了代表疲劳发生、作功能力下降的双曲线方程,通过分析衰竭时间和功、功率等参数的关系提出了衰竭阈概念。 相似文献
103.
104.
目的 探讨类比思维结合创设乐学情境教学在眼科护理实习教学中的应用研究。方法 选取2020年10月至2022年1月在空军军医大学第一附属医院西京医院眼科实习的90名护生作为研究对象。按照不同的教学方法分为对照组和观察组,对照组45名护生采用常规教学,观察组45名护生采用类比思维结合创设乐学情境教学。评估两组护生的综合考核成绩、教学效果调查问卷及学生对带教教师的总满意度。采用SPSS 22.0进行t检验和卡方检验。结果 观察组护生的理论知识考核成绩[(85.39±1.57) vs. (84.41±1.34)]、护理技能考核成绩[(87.52±0.04) vs. (82.64±0.05)均高于对照组;观察组护生的眼科护理工作中的用药安全意识、专业兴趣与自主学习性提升、协作组织能力增强、独立思考和自主学习能力提升、达到多学科知识融会贯通的目的、信息量与知识面改善、临床思维沟通交流能力增强、理论知识灵活应用、动手操作能力提高、培养创新意识各个方面评分均优于对照组;带教教师对学生学习态度、语言表达、呼唤沟通能力、独立解决问题能力等方面的评价,观察组高于对照组(P <0.05)。结论 类比思维结合创设乐学情境教学能提高护生的平均考核成绩和护理技能考核成绩,能改善学生对带教教师的满意度。 相似文献
105.
Michael Schirner Frank Herzberg Roland Schmidt Michael Streit Michael Schoning Michael Hummel Christine Kaufmann Eckhard Thiel Ernst-Dieter Kreuser 《Clinical & experimental metastasis》1997,16(5):427-435
The integrin 51 seems to be the most relevant receptor of tumor cells for binding to fibronectin. Although numerous studies suggest a role of tumor cell fibronectin interaction in tumor metastasis, differential integrin expression on tumor cells has, however, not been correlated with metastatic capabilities. We addressed this question by transfection of the integrin 51 cDNA into HT-29 human colon carcinoma cells which led to de novo expression of functional integrin 51. Similar to other reports, expression of the integrin 51 in HT-29 tumor cells exerted an inhibitory action on cell proliferation as indicated in our study by formation of fewer colonies in soft agar. The tumor growth inhibitory property of the integrin 51 was also shown by reduction of subcutaneous xenograft growth in nude mice to approximately 50% of that of control transfectants. For the first time, we found that several clones of integrin 5 subunit transfectants displayed dramatically reduced formation of lung colonies and cutaneous metastasis after intravenous injec-tion into nude mice. While most animals inoculated with control transfectant cells formed macroscopically visible lung colonies ranging from 12.6 ± 2.6 to 22.0 ± 6.6 (mean colony number ± SEM), mice inoculated with HT-29 cell clones expressing the integrin a5b1 were almost completely free of lung colonies (ranging from 0.0 ± 0 to 0.2 ± 0.1). Our results imply that integrin 51 expression inhibits circulating tumor cells in pursuing late steps of the metastatic process as represented by the artificial metastasis (lung colonisation) model. © Rapid Science Ltd. 相似文献
106.
目的 研究鼠巨细胞病毒(MCMV)感染对体外培养神经干细胞(NSCs)分化及分化基因表达的影响,探讨CMV先天感染致神经损伤的机制.方法 体外分离培养和鉴定BALB/c胎鼠NSCs并检测其分化潜能,用感染复数(MOI)为5、1和0.1的MCMV Smith毒株感染NSCs并进行分化培养,倒置显微镜下观察细胞形态学改变,流式细胞术检测分化细胞比率,免疫荧光法观察NSCs及其分化细胞标记物Nestin、胶质纤维酸性蛋白(GFAP)和神经元特异性烯醇化酶(NSE)表达的变化,采用MCMV早期抗原(EA)示踪感染过程(MOI=1),real-time RT-PCR检测分化早期NSCs Wnt信号途径关键分化基因Wnt-3和Wnt-Ta mRNA水平的动态变化.结果 体外培养的NSCs呈球样生长,神经干细胞特异性标记Nestin表达阳性,并可进一步诱导分化为NF-200阳性的神经元和GFAP阳性的星形胶质细胞;分化培养后,感染组NSCs不能贴壁分化生长并逐渐出现肿胀,细胞Nestin表达下调缓慢并显著高于正常对照组,而GFAP和NSE表达显著低于正常对照组(P<0.05),可检测到MCMV EA的阳性表达;分化培养3-9 d,感染组Nestin阳性细胞比率显著高于正常对照组,GFAP和NSE阳性细胞比率显著低于正常对照组(P<0.05);感染组Wnt-3 mRNA水平在分化培养后第1~2天显著低于正常对照组(P<0.05),感染组Wnto-7a mRNA水平在第0.5~2天明显低于正常对照组(P<0.05);感染组和正常对照组的差异随病毒MOI的增加而更加明显.结论 MCMV感染可明显抑制NSCs向神经元和星形胶质细胞方向分化,导致分化细胞比率减少;下调或干扰NSCs wnt信号途径分化基因wnt-3和Wnt-7a的表达;抑制NSCs分化及其分化基因表达的效应与MOI大小存在一定量效依赖关系;MCMV可能通过抑制NSCs分化基因的表达来抑制其分化,这可能是CMV先天感染致脑发育异常的重要机制之一. 相似文献
107.
痢疾杆菌免疫小鼠的GALT中T淋巴细胞亚群的应答状态 总被引:1,自引:2,他引:1
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。 相似文献
108.
M. Vandenbranden J.L. de Coen R. Jeener L. Kanarek J.M. Ruyschaert 《Molecular immunology》1981,18(7):621-631
Interactions between rabbit-γ-immunoglobulins and model membranes (lipid monalayers, planar lipid bilayers, liposomes) have been investigated. No significant interaction was observed with immunoglobulins. However, immunoglobulins dialysed first vs aqueous buffer having pH 2 or 3 and then dialysed against pH 7 buffer presumably adopt a new conformation which allows their bindings to model membranes. This binding is hydrophobic and the immunoglobulin region interacting with the lipid acyl chains is probably located in the heavy chain, as suggested by labelling in this region by a photosensitive probe previously incorporated into the lipid hydrophobic core. Cleavage at the hinge region by papain or pepsin, or heating above 38°C, induces the loss of the hydrophobic conformation responsible for hydrophobic bindings. The binding capacity of immunoglobulins heated above 38°C is restored after momentary dialysis at pH 2. The possible existence of two Ig isomers is discussed in relation to the mechanism of γ-immunoglobulin passage through the endoplasmic membrane and fixation into the plasma membrane. 相似文献
109.
In Ascaris muscle mitochondria the major respiratory chain-linked phosphorylation activity is accomplished by a NADH-linked reduction of fumarate to succinate. Oxygen can also be employed as a terminal electron acceptor via a cyanide- and salicyl-hydroxamate-resistant terminal oxidase. As in fumarate-dependent electron transport this process appears to be coupled to energy conservation at phosphorylation site I. The branchpoint from which electrons are taken from the main respiratory chain to either the alternative oxidase or fumarate reductase is likely to be on the oxygen side of the NADH dehydrogenase segment.Malate and succinate are the only substrates which appreciably support respiration in the mitochondrion of the nematode. Regardless of the presence or absence of oxygen malate is utilized by an oxidation-reduction reaction resulting in the formation of pyruvate, acetate, succinate, propionate and CO2. In addition, aerobically, hydrogen peroxide is formed as the product of oxygen reduction. Succinate accumulation was found to be significantly higher in the anaerobic as compared to the aerobic incubation mixtures. This effect was accompanied by an increase in anaerobic malate consumption. ATP generation and the formation of pyruvate, acetate and propionate were found to be similar in the presence and absence of oxygen.In malate-supported respiration of intact Ascaris mitochondria reducing equivalents (NADH) are produced exclusively through pyruvate and acetate formation. These enzymatic reactions are functionally coupled to the electron transport-linked reductions of fumarate to succinate and oxygen to hydrogen peroxide, respectively. In accordance with the position of the redox potentials of the fumarate/succinate and O2/H2O2 couples, anaerobic and aerobic respiration was found to be associated with relatively low energy conservation efficiencies. Thus one molecule of ATP was conserved per 2e? transferred to fumarate or oxygen, respectively. No evidence could be obtained for a significant activity of energy conservation sites II and III and electron transfer through the alternative oxidase pathway was shown not to be coupled to phosphorylation. 相似文献
110.
目的:探讨细胞因子Semaphorin 3a(Sema 3a)在小鼠胚胎视交叉发育过程中发挥的作用。方法:E13至E15小鼠胚胎的眼球至视束部分制备成脑厚片,置于含10%的小牛血清的DMEM/F12的培养液中,在37℃的恒温的滚动培养箱中培养5h。实验组中将Sema 3a抗体加入培养液中。培养结束后,将脑厚片以4%多聚甲醛固定,将DiI颗粒置于一侧视盘。7d后,在手术显微镜下,暴露被标记的视神经纤维,在激光扫描共聚焦显微镜下观察。结果:用Sema 3a抗体阻抑Sema 3a的功能,可引起E13跨越中线的视神经纤维减少以及神经纤维走行错误。结论:在视交叉形成的早期,Sema 3a可能吸引视神经纤维跨过中线,并且这个过程可能是短暂的。 相似文献