体表高频超声技术评价家兔血管成形术后再狭窄模型与病理学结果的相关性

目的:分析体表高频超声检测家兔血管内球囊成形术后再狭窄程度与组织病理学分析的相关性。评估体表超声检测的可行性、可靠性及应用价值。方法:实验于2002-03/2003-12在北京中医药大学中医内科学重点学科实验室完成。①日本大耳白兔26只,随机分为正常组10只、假手术组6只、模型组10只。②模型组电刺激兔颈总动脉,电流1.2mA,刺激12～15min,术后第2天喂饲高脂饲料共8周,假手术组仅剥离颈总动脉,不做电刺激,喂高脂饲料,正常组不施加任何干预因素。③模型组和假手术组根据B超选择颈总动脉有斑块或血流明显改变者行球囊血管内成形术。分别于电刺激后8周、血管成形术后4周行超声检查动脉内径和动脉内膜厚度。④所有动物于血管成形术后4周处死取材,进行病理学半定量分析,并与超声测量结果进行相关分析。结果:进入结果分析数量24只,正常组中途死亡1只,原因为牙齿畸型影响进食。模型组1只因电刺激8周时超声评价颈动脉未形成斑块及血流无明显改变而剔出实验。①超声检测电刺激8周时正常组内膜厚为(0.028±0.004)cm,模型组管壁明显增厚(0.043±0.014)cm,差异有显著性(P<0.05),至血管成形术后膜厚增加更明显(0.064±0.002)cm,内径稍有扩大,但差异不显著。②超声检测模型组颈动脉内径与膜厚的测量结果与病理学测量结果呈正相关关系(OR=0.361,P<0.05;OR=0.526,P<0.01),病理狭窄率与超声是否检测到斑块呈正相关关系(OR=0.796,P<0.01)。结论:体表高频超声在评价家兔颈动脉狭窄诊断中有一定应用价值,与病理学半定量分析结果相关性良好。     

快速成型骨组织工程支架的结构及力学仿生性能特征

目的:利用显微CT的成像技术及材料力学测试,观察多孔双相磷酸钙陶瓷支架的三维结构和力学仿生性能特征。方法:实验于2004-06/2005-12在清华大学新型陶瓷与精细工艺国家重点实验室、香港中文大学威尔士亲王医院骨与关节肌肉研究室和解放军总医院骨科研究所完成。利用三维凝胶叠层成型技术和发泡法复合的方法,制备仿骨多孔双相磷酸钙陶瓷支架,经显微CT扫描得到分辨率为20μm的断层图像,并按骨形态计量方法计算三维计量参数,并与急性脑死亡年轻人股骨头(由解放军总医院骨组织库提供,已签署捐献同意书)标本负重区松质骨样本的三维参数进行统计比较。最后对双相磷酸钙陶瓷支架两个互相垂直方向和松质骨样本的长轴方向进行压缩强度试验,计算压缩强度和弹性模量,并进行统计分析。结果:①双相磷酸钙陶瓷支架的小梁平均宽度和间距低于松质骨小梁(P<0.05);支架的小梁数目和各项异性程度高于松质骨样本(P<0.05);说明支架小梁在排列上呈现更为明显的各向异性特征。②双相磷酸钙陶瓷支架的体积分数、表面积体积比及结构模型指数与松质骨样本相比差异无显著性(P>0.05),两组样本均呈明显的板层结构。③力学测试结果显示双相磷酸钙陶瓷支架材料长轴方向的强度和弹性模量高于垂直方向(P<0.05),说明支架材料具有明显的方向性。长轴方向的强度低于正常松质骨样本,但弹性模量仅比松质骨样本弹性模量高20%(P<0.05)。结论:支架材料在空隙率和表面积方面具有很好的仿生性,利于细胞的黏附和长入。同时具有明显的方向性,提高了其在排列方向上的强度。弹性模量接近股骨头松质骨,具有较好的应力顺应性。     

大鼠骨髓间充质干细胞体外分离、纯化与培养适宜条件的筛选

目的:为获得大量、高纯度的骨髓间充质干细胞,筛选体外分离、纯化和培养的适宜条件。方法:实验于2006-08/2007-07在解放军兰州军区兰州总医院进行。①实验材料:2月龄SD大鼠,雄性,体质量(100±20)g,由解放军兰州军区兰州总医院实验动物科提供。②实验方法:分别采用全骨髓法(贴壁筛选法)和密度梯度离心法分离和纯化大鼠骨髓间充质干细胞。将采用密度梯度离心法获得的单个核细胞按1×107,1×108,1.5×108,2×108,1×109,2×109L-1的接种密度分别分成1～6组,接种在24孔板内,每组接种6孔。比较细胞出现伸展时间、原代培养时间。于细胞接种后第1,2,3,4,5,6天进行首次换液。将换下的部分细胞置于新的培养皿中进行培养,至少培养3d,观察是否还有新的贴壁细胞出现,以确定首次换液时间。观察体积分数为0.10,0.12,0.15,0.18,0.20血清对原代及传代后细胞生长的影响,比较不同浓度血清中细胞数量、集落形成率。集落形成率=集落数目/接种细胞数目×100%。采用流式细胞仪检测骨髓间充质干细胞细胞周期。选取第5代扩增的骨髓间充质干细胞,接近完全融合后进行成骨和成脂肪诱导培养。诱导剂分别为:10nmol/L地塞米松、0.05nmol/L抗坏血酸及10nmol/Lβ-甘油磷酸钠;1μmol/L地塞米松、0.5mmol/LIBMX、0.01mmol/L人胰岛素、0.01mmol/L吲哚美辛。并设未加诱导剂培养液培养的骨髓间充质干细胞对照。③实验评估:采用碱粒酶测定成骨诱导后细胞,采用油红O染色鉴定成脂肪诱导后细胞。结果:①细胞出现伸展时间、原代培养时间:密度梯度离心法培养细胞出现伸展时间与全骨髓法相比,差异无显著性意义。密度梯度离心法原代培养时间较全骨髓法长[(9.41±1.11),(14.73±2.86)d,P<0.05]。②不同接种密度对密度梯度离心法所获细胞生长影响:1×109L-1组细胞出现伸展时间及原代培养细胞融合时间较早。1×107L-1组培养20d内不能传代。③首次换液时间对细胞生长的影响:第5天开始在换下的液体中,很少有再贴壁的细胞出现。因此首次换液时间应为第5天。④不同体积分数血清对细胞生长的影响:在其他条件相同的前提下,骨髓间充质干细胞在含体积分数为0.12胎牛血清中细胞集落形成率最高。⑤成骨及成脂诱导:成骨诱导的骨髓间充质干细胞经碱粒酶测定,结果钙化结节呈蓝色。成脂诱导的骨髓间充质干细胞经油红O染色,苏木精-伊红复染后胞内脂滴呈桔红色,核呈蓝色。结论:采用密度梯度离心法分离纯化的骨髓间充质干细胞以1×109L-1密度接种,在含体积分数为0.12胎牛血清的MEM培养基中培养,生长状况良好,增殖速度快。     

Prevalence of asymptomatic left ventricular systolic dysfunction in hypertensive Nigerians: echocardiographic study of 832 subjects

Background

We sought to determine the prevalence of echocardiographically determined left ventricular systolic dysfunction in asymptomatic hypertensive subjects seen in Abeokuta, Nigeria.

Methods

Echocardiography was performed in 832 consecutive hypertensive subjects referred for cardiac evaluation over a three-year period.

Results

Data were obtained in 832 subjects (50.1% women) aged 56.0 ± 12.7 years (men 56.9 ± 13.3 years, women 55.0 ± 12.0 years, range 15–88). The prevalence of left ventricular systolic dysfunction (LVSD) was 18.1% in the study population (mild LVSD = 9.6%, moderate LVSD = 3.7% and severe LVSD = 4.8%). In a multivariate analysis, male gender, body mass index and LV mass were the predictors of LVSD.

Conclusion

Significant numbers of hypertensive subjects in this study had varying degrees of left ventricular systolic dysfunction. Early introduction of disease-modifying drugs in these patients, such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers may retard or prevent the progression to overt heart failure.     

Dithiothreitol liberates non-acid labile sulfide from brain tissue of H2S-poisoned animals

Acid-labile sulfide measured by conventional gas dialysis and ion chromatography with electrochemical detection accounts for only a proportion of the total sulfide present in brain tissue after poisoning with NaHS, an H₂S precursor. Dithiothreitol (DTT) displaced additional measurable sulfide not detectable by the conventional techniques from NaHS-poisoned brain tissue. Sulfide liberation by DTT was dose-dependent and maximal at higher DTT concentration (10 and 30 mM) and was thought to represent non-acid labile sulfide. Dithiothreitol was also found to be significantly protective against H₂S poisoning. Furthermore, in vitro inhibition by sulfide of monoamine oxidase (MAO) was reversed by DTT, thus suggesting a molecular mechanism consistent with known persulfide chemistry. Persulfide formation may thus underlie some aspects of hydrogen sulfide neurotoxicity. The rational development of antidotes for use in H₂S poisoning may thus have to be centered on strategies concentrating on known thiol, disulfide and persulfide chemistry.     

维拉帕米增强博莱霉素A5抗癌活性的机制

本文利用流式细胞术(FCM)和动物整体水平的同位素标记药物示踪方法探讨了维拉帕米(VP)增强博莱霉素A₅(BLM)抗癌活性的机制。实验发现VP显著增强BLM对S-180和HEP-2细胞的G₂期阻断效应。VP改变了⁵⁷Co-BLM在荷瘤小鼠部分器官中的分布,增加厂该药在肿瘤中的积聚。VP增強BLM抗癌活性可能是通过增加药物在肿瘤中的积聚,增强药物的G₂期阻断效应以及其它作用实现的。     

樟叶胡椒中新木脂素成分的研究

自胡椒科胡椒属植物樟叶胡椒(Piper polysyphorum C. DC)中分离到六个新木脂素(neolignans)类化合物,经光谱(UV,IR,MS,¹H-NMR,¹³C-NMR,2D-NMR,CD)分析及衍生物制备,确定Ⅱ为新化合物,即threo-△⁷-7-羟基-3,4,5,3′,5′-五甲氧基-8-O-4′-新木脂素,为一对对映体,命名为樟叶素(polysyphorin),Ⅰ,Ⅲ,Ⅳ为新的对映体,分別为(+)-virolongin,(+)-grandisin及(+)-lancifolin D.化合物Ⅴ为南藤素(wallichinine),Ⅵ为山蒟素D(hancinone D)。血小板活化因子(PAF)受体结合实验及PAF引起的血小板聚集实验证明化合物Ⅰ～Ⅴ具有明显的抑制活性。     

Osmotic gradient ektacytometry: comprehensive characterization of red cell volume and surface maintenance

Whole cell deformability of red cells was measured as a continuous function of suspending medium osmolality using the ektacytometer, a laser-diffraction viscometer. Study of normal cells in which water content and membrane surface area had been selectively modified showed that this technique can detect changes in these properties with high sensitivity. The osmotic deformability profiles obtained from this assay provide information about cell water content, surface area, and the heterogeneity in these cellular properties, information that by conventional methods would require several different types of measurements. Application of this approach to a variety of pathologic blood samples showed that various hematologic disorders can be characterized by the shape of this profile and the position of specific features of the profile along the osmolality axis. Measurement of osmotic deformability profiles thus provides a convenient and comprehensive means of identifying abnormalities either in red cell water content or surface area.