机械离心力对成骨细胞骨形态发生蛋白信号通路的影响

背景：Runx-2是骨形态发生蛋白信号的靶目标,骨形态发生蛋白信号转导通路参与了成骨细胞对机械离心力刺激的生理响应过程,而且在成骨细胞对力学信号引起的信息传递级联反应中扮演了重要角色。 目的：观察机械离心力对成骨细胞骨形态发生蛋白信号通路的影响。 方法：将MC3T3-E1细胞用体积分数为10%胎牛血清DMEM培养基预处理24 h后,分为对照组,90 r/min组、180 r/min及250 r/min组,每组再分为离心1,3,6 h亚组,给予不同转速和不同时间离心力刺激。对照组同步置于除离心外相同的环境中。收获细胞,提取总RNA,并反转录为cDNA,通过实时荧光定量PCR检测Runx2基因表达情况。 结果与结论：随着加力时间的延长,Runx2 mRNA的表达增加,二者成正相关,转速为180 r/min组的Runx2 mRNA表达明显高于90 r/min组和250 r/min组(P < 0. 01);90 r/min组和250 r/min组Runx2 mRNA的表达稍高于对照组,差异无显著性意义(P=0.119)。结果可见离心力大小和离心持续时间不同对成骨细胞骨形态发生蛋白信号通路的生理响应不同,该通路在对力学信号引起的信息传递级联反应中起重要作用。     

低渗刺激对成骨样细胞MG63功能的影响

目的本试验拟通过研究低渗透压的静牵张作用,对成骨样细胞MG63的增殖能力、碱性磷酸酶活性以及[Ca2 ]i的影响,探讨该应力形式下成骨样细胞MG63的力学响应特征。方法采用人成骨肉瘤来源的成骨样细胞MG63作为细胞源进行细胞培养传代。用不同渗透压的低渗透液,对成骨样细胞MG63分别进行2 h、4 h、8h、12 h和24 h持续牵张作用后,用免疫组化法检测ALP表达的情况,用ALP试剂盒检测ALP活性的变化,用钙试剂盒检测[Ca2 ]i含量波动情况。结果成骨样细胞MG63的ALP免疫细胞化学染色为阳性。随着作用时间的延长,成骨样细胞MG63在277 mOsm和240 mOsm低渗透液的持续性膨胀作用下,其细胞的[Ca2 ]i、ALP活性缓慢增高,但240 mOsm组ALP活性始终低于对照组(p<0.01);而细胞在163 mOsm低渗液作用下,8 h时出现[Ca2 ]i急剧升高(11.383±0.111),ALP活性(0.326±0.002)明显高于其对照组(p<0.01)。结论结果提示不同水平的低渗膨胀对MG63的增殖分化、ALP活性以及Ca2 -ATPase都有一定的影响作用,且Ca2 内流与ALP活性之间存在一定的相关性。低渗膨胀法作为一种应力形式有一定的实验意义。     

KC和FSC对肝细胞增殖及合成功能的影响

目的在于观察体外培养条件下，库普弗细胞（ＫＣ）贮脂细胞（ＦＳＣ）对肝细胞（ＰＣ）基质生成调节效应及ＰＣ增殖及合成功能的影响。采用ＦＳＣ、ＫＣ和ＰＣ的分离培养，观察ＫＣ和ＦＳＣ对ＰＣ增殖活性和ＤＮＡ含量的影响，应用免疫细胞化学和图像分析系统对ＰＣ中Ⅰ、Ⅱ、Ⅳ型胶原和纤维粘连蛋白（ＦＮ）进行定量分析，以及用液闪法检测ＰＣ中３Ｈ－脯氨酸掺入量。结果证明ＦＳＣｎｃｍ可明显促进ＰＣＤＮＡ合成，ＰＣ可合成Ⅰ、Ⅲ、Ⅳ型胶原及ＦＮ。ＦＳＣｎｃｍ可促使双核的ＰＣ增多，线粒体分裂。提示肝细胞可合成Ⅰ、Ⅲ、Ⅳ型胶原及ＦＮ；ＰＣ内可能直接组装胶原纤维；ＫＣｎｃｍ、ＫＣｔｃｍ、ＦＳＣｔｃｍ均可上调ＰＣ的基质合成能力。     

DKK1基因沉默的人多发性骨髓瘤细胞培养上清对小鼠前成骨细胞成骨分化的影响

 目的：初步探讨一种与胚胎发生及肿瘤发展密切相关的糖蛋白Dickkopf-1（DKK1）在骨髓瘤骨病（myeloma bone disease,MBD）发病中的作用。方法：前期实验构建的质粒pLenti6/V5-GW/DKK-1-miR,与慢病毒包装质粒一起包装成慢病毒,感染人骨髓瘤U266细胞,建立DKK1沉默的U266细胞。小鼠前成骨细胞MC3T3-E1体外成骨诱导实验分组：空白对照组、诱导分化组、30% U266上清干预组、30% DKK1 RNAi U266上清干预组和30%无关序列RNAi U266上清干预组;诱导培养12 d后,通过茜素红染色检测钙结节数目;real-time PCR检测骨钙素（osteocalcin,OC）mRNA的表达变化。结果：成骨诱导体系中,与空白组比较,诱导组OC mRNA有明显升高,差异有统计学意义（P<0.01）。与诱导组比较,30% U266上清干预组OC mRNA表达明显减少（P<0.01）。与30% U266上清干预组比较,30% DKK1 RNAi U266上清干预组OC mRNA表达明显增多（P<0.05）,30%无关序列RNAi U266上清干预组OC mRNA差异无统计学意义。与诱导组比较,30% U266上清干预组钙结节计数明显减少（P<0.01）。与30% U266上清干预组比较,30% DKK1 RNAi U266上清干预组钙结节计数明显增多（P<0.05）,30%无关序列RNAi U266上清干预组钙结节计数差异无统计学意义(P>0.05)。结论：U266细胞中DKK1基因沉默后,其培养上清抑制小鼠前成骨细胞MC3T3-E1成骨分化的能力减弱。     

β-蜕皮甾酮促进小鼠前成骨细胞体外增殖及诱导成骨分化

文题释义：β-蜕皮甾酮：又称蜕皮激素、20-羟基蜕皮甾酮,分子式C₂₇H₄₄O₇,为黄棕色至白色粉末,味苦;主要存在于昆虫、蚕、露水草、牛膝、川牛膝等动植物体内,具有调节血糖血脂、促进胶原蛋白合成、抗疲劳、促进细胞生长和刺激真皮细胞分裂等作用,目前广泛应用于化妆品、医疗以及养殖业等领域。骨形态发生蛋白质2：是从脊椎动物骨骼基质中分离提纯的蛋白质,具有内肽酶活性、表皮生长因子模体,同源二聚体之间以二硫键相连,属于转化生长因子β家族,能诱导骨与软骨形成。骨桥蛋白：存在于矿化和活性沉积区,是一种含有Arg-Gly-Asp(RGD)结构的酸性糖蛋白,它与诱导成骨细胞成熟表型表达和矿化骨基质形成的活性蛋白密切相关。在成矿阶段,骨连接素、纤连蛋白与骨桥蛋白的表达高度相关。Ⅰ型胶原是钙盐沉积和细胞附着的支架,可促进细胞附着并刺激细胞分化。背景：β-蜕皮甾酮作为“植物类雌激素”不仅具有刺激蛋白质合成,促进碳水化合物和脂质代谢,缓解高血糖、高脂血症,以及保护内皮细胞免于凋亡并诱导其增殖的多种生物活性,而且有学者报道其在治疗骨质疏松症、骨折和其他骨骼炎症性疾病方面也有着重要的作用。 目的：观察β-蜕皮甾酮对小鼠前成骨细胞(MC3T3-E1细胞)体外增殖的影响,以及在安全剂量下,β-蜕皮甾酮是否对该细胞具有诱导成骨分化的作用。方法：取第4代MC3T3-E1细胞在成骨诱导分化培养基中培养7,10,14,21,28 d后,检测细胞不同时间段成骨分化蛋白(碱性磷酸酶、Ⅰ型胶原蛋白、骨桥蛋白以及钙化结节)的表达量,以鉴定该细胞是否具有成骨分化的能力;然后将MC3T3-E1细胞接种于含不同终浓度β-蜕皮甾酮(0.01,0.1,1,10,100 µmol/L)的诱导培养基中,分别于第1,2,3,4,5,6,7天利用CCK8法检测细胞的增殖活性;最后设置对照组(普通诱导培养基组)和实验组(普通诱导培养基+β-蜕皮甾酮),在相同条件下进行培养,并测定不同时间段各组细胞成骨标志蛋白的表达量。结果与结论：①MC3T3-E1细胞在成骨诱导培养基刺激下,第10天碱性磷酸酶染色以及Ⅰ型胶原蛋白荧光染色表达较高,同时碱性磷酸酶活性检测也验证了这一结果(P < 0.05);诱导培养第14天骨桥蛋白免疫细胞化学染色也有明显表达;茜红素染色显示成骨诱导后的细胞较对照组结节数量明显增加,第28天比第21天的钙结节形成数目更多、直径更大、颜色更深;②CCK 8法测得β-蜕皮甾酮对MC3T3-E1细胞作用5 d后增殖活性达到最佳,促增殖活性最佳剂量为0.01 µ mol/L、0.1 µmol/L,2种浓度之间差异无显著性意义(P > 0.05);③实验组细胞经β-蜕皮甾酮诱导培养第10天较对照组细胞碱性磷酸酶、Ⅰ型胶原蛋白表达更高;第14天实验组细胞内骨桥蛋白、骨钙素表达更高;第28天2组钙结节染色无明显差异;④结果说明,β-蜕皮甾酮能促进MC3T3-E1细胞体外增殖,且在安全剂量下能提高MC3T3-E1细胞向成骨细胞分化的能力。ORCID: 0000-0001-5641-6353(严才平) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

不同离心条件对HBsAg检测结果的影响

目的通过全自动微粒子化学发光法检测乙肝表面抗原(HBsAg)的反应结果,探讨不同离心条件对HBsAg检测结果的影响。方法取本院临床患者静脉血3 ml于分离胶促凝采血管中,均分为2管,分别用3 600 r/min(2 898 g)10 min和8 819 r/min(10 000 g)10 min分离血清,分别检测上清液中HBsAg含量。共收集临床标本324份,对测定结果通过卡方检验分析不同离心速度组间检测结果是否有差异。检测仪器为美国雅培公司I2000全自动微粒子化学发光免疫分析仪,检测试剂为雅培公司的仪器配套试剂。并将乙肝表面抗原浓度在0.05～10 IU/ml的224份弱阳性血清标本进行确认试验,对比两种离心条件下的乙肝表面抗原检测假阳性率。结果卡方检验分析结果表明,两种离心条件下的乙肝表面抗原检测结果有统计学差异(P<0.001)。HBsAg浓度处于0.05～0.44 IU/ml范围内的弱阳性标本在不同离心条件后的检测结果有统计学差异(P<0.05),其他范围内的标本结果无统计学差异(P>0.05)。抗体中和确认试验阳性202例,则2 898 g 10 min分离血清,检测上清液中HBsAg含量的假阳性率为9.82%。10 000 g 10 min分离血清检测不会导致假阴性标本出现。结论获得准确、快速的检验结果,标本的质量更关键。严格按照试剂说明书规定的标本采集要求,离心操作,就可得到准确的实验结果。这说明,标本的离心处理好坏直接影响实验结果的准确性。对HBsAg低值弱阳性标本,应进行高速离心复核,抗体中和确认试验可作为HBsAg弱阳性标本进一步确认的手段。     

人皮肤成纤维前体细胞的分离培养及其功能鉴定

目的以人的皮肤为材料,拟在体外成功分离培养成纤维前体细胞并研究其除皱整形能力。方法组织块法分离人的皮肤成纤维前体细胞,并通过RT-PCR、流式细胞仪、软琼脂克隆等实验技术对分离的皮肤成纤维前体细胞进行鉴定,同时进行免疫荧光、动物实验检测其在治疗真皮损伤以及除皱整形方面的作用。结果成功分离并扩增人的皮肤成纤维前体细胞,优化了原代细胞的分离方法,RT-PCR和流式细胞仪检测结果显示该细胞表达部分干细胞表面标记HLA-I、HLA-DR、CD90以及CD105,软琼脂克隆实验表明该细胞不具有致瘤性。免疫荧光结果显示,注射该细胞的裸鼠与对照组相比,真皮层产生更多的I型胶原蛋白,皮肤厚度增加。结论一次取材,体外能够成功持续获得人的原代皮肤成纤维前体细胞,优化了原代细胞分离方法。并且该细胞注射后可以在一定程度上分化为成纤维细胞,产生胶原蛋白,修复受损皮肤。     

纳米级多孔负载人骨形成蛋白2基因修饰支架对前成骨细胞株分化的影响

BACKGROUND: Bone tissue transplantation or osteogenic material filling is after used for bone defect repair. To remove autologous bone tissues can lead to additional damage and secondary deformity, therefore, it is extremely urgent to search for a new osteogenic material. OBJECTIVE: To construct the porous β-tricalcium phosphate (β-TCP)/collagen scaffold modified with human bone morphogenetic protein 2 (hBMP2) gene, and to observe its effects on differentiation of MC3T3-E1 cell lines. METHODS: The porous β-TCP/collagen scaffold modified with hBMP2 gene was prepared. Then in vitro culture system of MC3T3-E1 cell lines with composite scaffold was established. There were scaffold and plate groups, and each group was divided into two subgroups according to the different concentrations of plasmid. Samples were collected and observed morphologically by scanning electron microscope and light microscope after complex culture. After 1, 3, 7 and 14 days of induction, calcium nodules were observed through alizarin red staining, the cell cycle was detected by real-time PCR, and expressions of α I-chain collagen type I gene, Osterix and bone sialoprotein were observed. RESULTS AND CONCLUSION: The number of cells adhered, differentated and distributed on the composite scaffold was significantly higher than that of the single scaffold (P < 0.05). Alizarin red staining and real-time PCR detection showed that the osteogenesis ability of MC3T3-E1 cell lines in the scaffold group was stronger than that in the plate group. To conclude, the porous β-TCP/collagen scaffold modified with hBMP2 gene is an appropriate candidate for bone defect repair.     

骨折稳定性对梯形加压钢板疲劳强度的影响

目前对骨折内固定术后负重状态下钢板疲劳强度缺乏了解。本文选用新鲜成人尸体股骨制备７种股骨干骨折模型，以梯形自动加压钢板固定。在靠近骨折线的中央螺孔边缘贴应变片。通过模拟负重电测试验及疲劳强度计算，认为骨折失稳是导致钢板疲劳强度下降的内在原因。骨折断端之间牢固固定，依据钢板的工作安全系数合理地指导负重功能练习，有助于增加现有内固定钢板使用的安全性。临床实践表明，骨折部位骨缺损－尤其是压力侧－在负重状态下可导致钢板破坏［１］。尽管失效分析认为钢板破坏属疲劳破坏［２］，由于对加压钢板固定骨折后负重状态下的疲劳强度知之较少，人们不能肯定固定长骨骨折后负重时钢板是否安全。本文采用模拟电测试验与疲劳强度计算相结合的方法，对梯形加压钢板（ＴＣＰ）的疲劳强度做一初步分析。     

镁离子联合矿化胶原干预小鼠前成骨细胞的成骨分化

文题释义：前成骨细胞：形态呈梭形,是成骨细胞的前体,由基质干细胞分化,沿着成骨细胞谱系发育而成,位于覆盖骨形成表面的成骨细胞外侧,能定向分化为成骨细胞生成骨基质。 矿化胶原人工骨：又名纳米羟基磷灰石/胶原,是基于仿生观念制成的骨组织工程支架材料,具有纳米量级的晶体尺寸及多孔的三维构造,结构与天然骨相似。 背景：课题组前期研究证实,镁基金属与矿化胶原联合应用在修复极限缺损时具有良好的支撑效果,可在一定程度上改善矿化胶原机械强度过差及在骨愈合期间过早塌陷的问题。然而,镁基金属在含氯化物溶液(包括人体体液或血浆)中降解较快,其中释放镁离子对成骨细胞增殖分化等的影响尚不清楚。 目的：分析镁离子联合矿化胶原对小鼠前成骨细胞体外成骨分化能力的影响。 方法：分别采用镁离子浓度为0,5,10,20 mmol/L的完全培养基制备矿化胶原浸提液,以4种矿化胶原浸提液培养小鼠前成骨细胞,分别设为矿化胶原组及5,10,20 mmol/L Mg²⁺+矿化胶原组,以完全培养基培养的小鼠前成骨细胞为空白对照组。观察细胞的形态、增殖、凋亡、细胞内微丝肌动蛋白与成骨诱导分化后的碱性磷酸酶活性及成骨基因Runx2的表达。 结果与结论：①培养24 h,矿化胶原组、5,10 mmol/L Mg²⁺+矿化胶原组细胞贴壁情况良好,与空白对照组无明显差异,细胞形态呈长梭形,表面有多个突触与邻近的细胞相联系;20 mmol/L Mg²⁺+矿化胶原组细胞呈现明显的核浓缩;②培养1,3,5 d时,10 mmol/L Mg²⁺+矿化胶原组细胞活力高于其余4组(P < 0.05),矿化胶原组、5 mmol/L Mg²⁺+矿化胶原组与空白对照组无差异(P > 0.05),20 mmol/L Mg²⁺+矿化胶原组低于空白对照组(P < 0.05);③培养3 d后DAPI染色显示,20 mmol/L Mg²⁺+矿化胶原组可见明显细胞核解体的现象,其余4组未见明显细胞核解体;④培养24 h后鬼笔环肽染色显示,除空白对照组、20 mmol/L Mg²⁺+矿化胶原组外,其余3组细胞结构完整伸展,肌动蛋白微丝清晰明显,尤以10 mmol/L Mg²⁺+矿化胶原组最为明显;⑤成骨诱导分化7 d后,除20 mmol/L Mg²⁺+矿化胶原组外,其余3组碱性磷酸酶活性与Runx2基因表达均高于空白对照组(P < 0.05),且10 mmol/L Mg²⁺+矿化胶原组高于5 mmol/L Mg²⁺+矿化胶原组、矿化胶原组(P < 0.05);⑥结果表明,镁离子与矿化胶原联合应用需要在适当的镁离子浓度范围(≤10 mmol/L)下进行。 ORCID: 0000-0002-1870-2946(孙溪饶) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

高压培养及卡托普利干预对猪离体主动脉内皮细胞功能的影响

目的：利用高压培养猪离体主动脉血管内皮细胞的实验模型，研究高压刺激对血管内皮细胞增殖及分泌一氧化氮（NO）、内皮素（ET）的影响及卡托普利（Cap）、去甲肾上腺素（NE）的干预作用。方法：制备3-6代猪主动脉血管内皮细胞的单细胞悬液，分为4个组，每组8孔，5×10⁴个细胞/孔，①对照（control）组，②Captopril（10^-5 mol/L）组，③Norepinephrine（100 μg/L）组，④Captopril+norepinephrine组，培养1、3、5 d后，进行细胞计数，培养48 h后测培养液中的NO和ET含量。结果：①细胞生长试验：Cap组细胞数明显少于对照组（P<0.01）而NE组细胞数明显多于对照组（P<0.01），NE+Cap组与对照组无显著差异。②猪主动脉内皮细胞分泌NO及ET含量：Cap组ET含量低于而NO含量高于对照组（P<0.01）；而NE组ET含量高于而NO含量低于对照组（P<0.01），NE+Cap与对照组无显著差异。结论：卡托普利抑制高压培养PAEC的增殖，抑制ET分泌，促进NO分泌，而NE则具有相反作用；卡托普利能对抗NE对PAEC的作用。     

Effects of extracellular magnesium on the differentiation and function of human osteoclasts

Magnesium-based implants have been shown to influence the surrounding bone structure. In an attempt to partially reveal the cellular mechanisms involved in the remodelling of magnesium-based implants, the influence of increased extracellular magnesium content on human osteoclasts was studied. Peripheral blood mononuclear cells were driven towards an osteoclastogenesis pathway via stimulation with receptor activator of nuclear factor kappa-B ligand and macrophage colony-stimulating factor for 28 days. Concomitantly, the cultures were exposed to variable magnesium concentrations (from either magnesium chloride or magnesium extracts). Osteoclast proliferation and differentiation were evaluated based on cell metabolic activity, total protein content, tartrate-resistant acid phosphatase activity, cathepsin K and calcitonin receptor immunocytochemistry, and cellular ability to form resorption pits. While magnesium chloride first enhanced and then opposed cell proliferation and differentiation in a concentration-dependent manner (peaking between 10 and 15 mM magnesium chloride), magnesium extracts (with lower magnesium contents) appeared to decrease cell metabolic activity (≈50% decrease at day 28) while increasing osteoclast activity at a lower concentration (twofold higher). Together, the results indicated that (i) variations in the in vitro extracellular magnesium concentration affect osteoclast metabolism and (ii) magnesium extracts should be used preferentially in vitro to more closely mimic the in vivo environment.     

长期培养的大鼠原代肝细胞功能和形态学观察

目的：研究大鼠原代肝细胞长期体外培养后功能和形态的变化。 方法： 采用两步胶原酶原位灌流法分离大鼠肝细胞，并用Percoll分离液进行密度梯度离心进一步纯化肝细胞，采用0.4%台盼蓝染色观察细胞活力。然后将细胞接种于HepatoZYME-SFM培养基中培养，定期收集肝细胞培养液上清检测丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶（AST）、白蛋白、尿素氮的水平。采用乙氧基试卤灵O-脱乙基酶活性（EROD）方法检测肝细胞P450的CYPⅠA1功能。 结果： 新鲜分离的大鼠肝细胞总数（2-3）×108cells/whole liver，Percoll分离液纯化后活力和纯度在90%以上。HepatoZYME-SFM培养下肝细胞生长良好并保持正常形态。AST、ALT水平在培养3 d后下降显著，6-9 d后趋于相对稳定的低水平。白蛋白的分泌功能、尿素合成能力在18 d内维持在较高水平。可在3-6 d检测到CYPⅠA1酶活性。 结论： Percoll液纯化新分离肝细胞可提高其活率和纯度，HepatoZYME-SFM培养条件下肝细胞可有效保持良好形态结构和一定的生物合成代谢能力，适合肝细胞的体外长期培养和功能研究。     

Effects of intra-abdominal pressure on adrenal gland function and morphology in rats

Intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) are life-threatening conditions and caused by several clinical status. Although there is insufficient data regarding its effects on adrenal glands. This study aimed to identify whether elevated intra-abdominal pressure (IAP) caused any alteration on the morphology and function of adrenal glands in a rat model. Twenty four Sprague-Dawley male rats were included in the study. Animals were allocated into 4 groups. IAP was elevated to 15 mmHg for one hour and four hours in group 2 and 4. Group 1 and 3 were sham groups. Blood samples were taken for the assessment of plasma adrenaline, noradrenaline, and corticosterone levels and adrenalectomies were performed to evaluate apoptosis. Blood adrenaline, noradrenaline and corticosterone levels were significantly higher in the study groups compared with the sham groups. However, there were no significant changes in apoptotic index scores in the study groups as compared to sham groups. These results support that increased IAH leads to discharge of catecholamine and corticosterone from the adrenal glands. Failure to demonstrate similar changes in apoptotic index score may be concluded as apoptosis is not a leading pathway for impairment of adrenal glands during IAH period.     

Red cell flexibility and electrical resistance of blood centrifuged at low g-values

Summary The migration velocity of a red cell in a gravitational field depends in part upon the ability of the cell to adapt its shape to the external shearing forces, i.e. to achieve a hydrodynamically optimal streaming profile. The degree of shape transformation depends upon the strength of the shearing forces and on the deformability of the cells. It is shown that a close relation exists between migration speed and red-cell flexibility. The new method is sensitive enough, to reveal even minute differences in cell flexibility caused by surface-active substances such as bile, free fatty acids or noradrenaline i.v.     

关节腔渗透压调控骨关节炎的研究进展

骨关节炎是一种慢性、进行性、不可逆性的关节退行性疾病,是一种中老年人的常见疾病,被认为是全球致残率较高的疾病之一.近年来,随着经济发展和人口老龄化,骨关节炎的患者数量在不断增加,这也让骨关节炎在临床上得到了极大的重视.而临床上治疗骨关节炎的一个关键性问题是关节软骨的丢失和难以自我修复.渗透压可以通过调节细胞体积和调控离...     

Effects of centrifugation on living oocytes from adult Japanese quails

Summary After centrifugation of adult quail oocytes, RNA-containing structures move in a centrifugal direction. By a moderate-speed centrifugation of quail oocytes at the end of the lampbrush or beginning postlampbrush chromosome stage, one can demonstrate that the germinal vesicle has a lower density than the surrounding ooplams. This indicates that the formation of the post-lampbrush stage and accompanying development of the germinal disc is codetermired by a gravitational (epigenetic) phenomenon. With increase in diameter of the oocyte, the cohesion between its cytoplasmic constituents progressively diminishes. The localization of the RNA-rich basophilic cortical layer after centrifugation can be followed accordingly as the oocyte grows: from a cap at the centrifugal pole in late lampbrush stage, it is progressively pushed centripetally by the peripherally formed heavy yolk that accumulates centrifugally during the postlampbrush stage.The author is very grateful to Prof. Dr. L. Vakaet, R.U.C.A., Antwerpen, and Dr. W. Baeyens, Radiobiology S.C.K., Mol, for their valuable suggestions. The excellent technical assistance of Mrs. S. De Wolf-Van Rompaey is gratefully acknowledged.     

高压对耳蜗的影响

目的研究高压环境对人耳蜗的影响,弥补试验手段不足导致的耳蜗在高压环境下听力行为特征研究的缺失,为今后对耳蜗进行针对性研究提供新的思路。方法基于健康人耳蜗CT扫描图像,结合自编程序,利用PATRAN软件建立三维螺旋耳蜗有限元模型。应用NASTRAN软件进行流固耦合频率响应分析和瞬态响应分析,通过数值模拟方法研究高压对耳蜗的影响。结果基底膜12 mm处与镫骨底板中心(卵圆窗的中心)处位移比值模拟结果与已报道的试验结果相吻合,验证了所建模型的正确性。高压环境下,耳蜗中基底膜特征频率点的幅值随着压强的增大而不断减小。结论高压环境最终导致人耳听力的降低。研究结果为临床上研制防治高压的缓冲装置提供理论支撑。     

Measurement of pressure under the foot during function

The design of a suitable transducer to measure the pressure under the foot it presented. The transducer is attached to the sole of the foot and can, if required, be worn inside shoes. A system is described using up to 16 transducers, the analogue signals from which are digitised online and stored on magnetic tape for subsequent computer analysis. Examples of the data obtained form patients with arthritic involvement of the feet and from normal subjects, both walking with and without shoes, are given. The importance of the clinical application of this type of measurement is discussed. Proofs and reprints are available from R. W. Soames, Department of Anatomy, King's College London, Strand, London WC2R 2LS, England     

Effects of retinol on follicular porcine thyrocytes in culture

Retinoids influence proliferation and differentiation in transformed thyroid cell lines. Retinoids are able to damage cells by destabilizing lysosomal membranes and induce apoptosis in certain cell lines. In normal thyrocytes retinol modulates iodine metabolism. At concentrations higher than 50×10^–6 M retinoids are cytotoxic for normal (not transformed) thyroid cells. The mechanism of this cytotoxicity is unknown. We studied the effect of 7–80×10^–6 M retinol on porcine follicular thyrocytes in culture. In order to differentiate between membrane-destabilizing effects and apoptosis we investigated cultures after incubation with retinol by light- and electron-microscopy and by labeling of potential nicks in the DNA helix by terminal deoxynucleotidyltransferase-dUTP mediated DNA nick end labeling. We conclude that the observed cytotoxicity is caused mainly by the induction of apoptosis.