玻璃化法和低温冷冻法保存兔股动脉活性的差异

背景：异体血管保存常用的低温冷冻法会不可避免地形成大量冰晶,因此所保存的血管活性有限。玻璃化法可避免冰晶所造成的挤压损伤和冻融效应,尤其适合于活性组织的保存。目的：比较玻璃化法和低温冷冻法保存兔股动脉组织结构和收缩舒张能力的差异。设计、时间及地点：组织形态学及力学水平的随机对照实验,于2002-09/2006-08在解放军总医院骨科研究所完成。材料：纳入新西兰兔18只,按随机数字法分为3组,玻璃化法保存组、低温冷冻法保存组及新鲜血管组各6只,每组取12条股动脉。方法：切取股动脉标本,置于平衡液中备用。玻璃化法保存组血管在4℃条件下经25%,50%和100%梯度玻璃化溶液浸泡后,直接投入液氮中。低温冷冻法保存组血管由常温状态下,经过0,-20,-70℃梯度降温,平衡60min,直接投入液氮中。将新鲜动脉作为对照,样本在液氮中保存14d以上。主要观察指标：对动脉组织进行细胞培养和鉴定,测定动脉环张力随去甲肾上腺素和硝普钠剂量的变化。结果：3组动脉培养均为平滑肌细胞,玻璃化法保存组生长速度与新鲜血管组相近,而优于低温冷冻法保存组。玻璃化法保存组与新鲜血管组动脉环最大收缩力差异无显著性意义（P〉0.05）,玻璃化法保存组、新鲜血管组动脉环最大收缩力显著大于低温冷冻法保存组（P〈0.01）。当去甲肾上腺素剂量为10-6mol/L时,动脉开始明显收缩;当去甲肾上腺素剂量为10-4mol/L时,动脉收缩力达到最大。玻璃化法保存组、低温冷冻法保存组及新鲜血管组动脉环最大舒张程度差异无显著性意义（P〉0.05）。当硝普钠剂量为10-7mol/L时,动脉开始产生明显的舒张反应;当硝普钠剂量为10-4mol/L时,动脉基本达到最大舒张程度。结论：玻璃化法保存的动脉较低温冷冻法具有更多的活性平滑肌细胞,尽管玻璃化法保存的动脉在对去甲肾上腺素的收缩能力方面优于低温冷冻法保存的动脉,但是对硝普钠的舒张能力上二者之间没有差别。     

液氮保存时间对脱细胞血管基质支架材料组织形态及力学特性的影响

背景:血管脱细胞组织基质作为天然生物支架材料的制备与临床应用具有一定的时差,保存条件对其影响逐渐收到人们重视.目的:拟观察不同液氮保存时间对脱细胞血管基质支架材料组织形态及力学特性的影响.设计、时间及地点:随机分组设计,对比观察,于2007-08/2008-05在青岛市市立医院心脏外科实验室完成.材料:健康新西兰兔10只,体质量550～600 g,用于制备脱细胞血管基质.方法:采用胰蛋白酶、低渗溶液、化学除垢剂法处理兔胸主动脉制备脱细胞血管基质.根据液氮保存时间的不同将制取的血管随机分为液氮1月组,液氮2月组和液氮3月组;另设新鲜组:未用液氮保存而作为对照.主要观察指标:苏木精-伊红染色、扫描电镜观察各组脱细胞血管基质形态变化,并作力学测试,包括Lagrange应变、Lagrange应力、伸长比和极限应力.结果:苏木精-伊红染色可见新鲜组血管脱细胞组织基质中胶原纤维和弹性纤维保持原来的形态和结构,呈网状排列,细胞已基本去除.液氮保存组光镜下见与新鲜组无明显差异.扫描电镜见新鲜组血管脱细胞组织基质的纤维结构完整,胶原纤维无断裂,为网状和多孔状,孔径为(100～150)×(10～20)μ m.液氮保存组胶原纤维结构完整,呈网状捧列,胶原纤维无断裂现象,孔径与新鲜组无明显差异.各组力学指标相比,差异无显著性意义(P>0.05).结论:不同液氮保存时间对脱细胞血管基质的形态学、组织学以及力学特性方面没有明显影响.     

玻璃化法处理同种异体动脉的移植

背景:体外血管预处理及保存方法有多种,经过学者们长期大量的研究观察,各种方法均得到了改进,但是仍然存在弊端.因此找到一种更有效的或者几种体外血管预处理保存方法的结合,还需要人量的研究实践.目的:拟通过比较玻璃化法和传统冷冻法保存处理的同种异体血管移植后效果,找出一种更为实用且制作简便的血管处理方法.方法:选用健康青紫兰兔96只,手术切除双侧股动脉,根据不同体外血管预处理方法将实验分为3组,即新鲜血管自体移植组、冷冻+辐照颅处理血管同种异体移植组及玻璃化+辐照预处理血管同种异体移植组.血管移植后1,2,8,12周,每组取6只动物进行腹毛动脉数字减影血管造影、扫描电子显微镜、组织病理学观察,观察移植血管通畅率、动脉瘤形成情况及组织形态学变化.结果与结论:移植后12周,新鲜血管自体移植组血管的累计通畅率最著高于冷冻+辐照预处理组(P<0.05),玻璃化+辐照预处理组与其他两组比较,差异无显著性意义(P0.05).组织病理学检查显示,玻璃化+辐照处理的同种异体血管内膜及中层平滑肌增牛较冷冻+辐照预处理组轻,管腔狭窄不明显,炎症反应较轻.经玻璃化法+辐照保存的同种异体血管制作程序简单,移植血管通畅率高,组织反应轻,是一种比较理想的同种异体血管体外处理方法.     

肌腱玻璃化法冷冻保存的体外实验

目的:目前临床上常用低温冷冻法来保存同种异体肌腱,但操作较复杂费时,并且所保存的肌腱活性较低而限制其应用。采用已筛选的玻璃化法冷冻保存鸡屈趾深肌腱,并将复温后的玻璃化肌腱进行体外检测,探索其作为肌腱移植材料的可行性。方法:实验于2003-11/2005-02在解放军总医院骨科研究所完成。①实验材料及分组:来亨鸡16只,雄性,体质量2.5kg左右,随机分为2组,玻璃化组为玻璃化肌腱,新鲜肌腱组为新鲜肌腱,每组8只。②实验过程:切取来亨鸡屈趾深肌腱,置入玻璃化液内快速投入液氮保存2周制备玻璃化肌腱。③实验评估:将2组肌腱在体外进行大体、组织学及超微结构观察,羟脯氨酸含量测定,生物力学性能检测,并对两组肌腱进行细胞培养与鉴定。结果:①玻璃化组肌腱的大体、组织学及超微结构与新鲜肌腱组相似,其细胞及细胞外结构得以良好保存。②应用碱解法测定玻璃化肌腱内的羟脯氨酸含量为69.27mg/g,与新鲜肌腱组间差异无统计学意义。③玻璃化组肌腱破裂强度为165.58MPa,弹性模量1.41GPa,与新鲜肌腱组的力学性能差异无统计学意义。④将玻璃化组肌腱进行细胞培养,细胞第8天自组织块长出,第21天后传代,培养3代后出现明显的退化现象,其生物学特性与新鲜肌腱组相似。⑤将两组肌腱培养的细胞分别进行免疫组织化学染色,经鉴定均为肌腱细胞。结论:玻璃化法保存的肌腱具有良好的细胞活性、细胞外结构及力学性能,其生物学及生物力学特性无明显变异。     

不同冷冻方案保存人类卵巢组织的活性比较

背景：卵巢组织冷冻保存被认为是保存女性生殖内分泌功能安全、有效的方法,但目前尚无统一确定的方案。 目的：探讨3种冷冻方案对人类卵巢组织保存冷冻效果及卵泡活性的影响。方法：采用丙二醇慢速程序冷冻法、二甲基亚砜玻璃化冷冻法、液氮直投法对20例人类卵巢组织进行冷冻保存,复苏后采用细胞存活/死亡荧光分析法计数有活性的细胞,体外培养测定培养液雌二醇浓度及各级卵泡计数,判断3种不同冷冻方案对人类卵巢组织活性的影响。结果与结论：不同冷冻方案冻融后卵巢组织块的活性卵泡率均低于新鲜卵巢组（P 〈 0.05）,二甲基亚砜组最低,液氮直投法组与慢速程序冷冻法组差异无显著性意义。体外培养各冷冻组分泌的雌二醇水平比较,第4天时二甲基亚砜组低于液氮直投法组和慢速程序冷冻法组（P 〈 0.05）,至第8天时各冷冻组雌二醇水平与新鲜卵巢组一致。培养14 d组织学观察,各组卵巢组织内生长期卵泡比例增多,始基卵泡仍然占最主要的。新鲜卵巢组织正常卵泡的总数高于冷冻组（P 〈 0.05）,二甲基亚砜组的正常卵泡数低于液氮直投法组和慢速程序冷冻法组（P 〈 0.05）。提示冷冻保存对卵巢组织卵泡有一定的损伤,但仍能保存大部分始基卵泡的活性,经体外培养后可进一步发育并具有分泌功能,在3种冷冻方案中,慢速程序冷冻法和液氮直投法的冷冻效果优于二甲基亚砜玻璃化冷冻法,液氮直投法操作简便,冷冻效果稳定。     

深低温冷冻骨的形态学及免疫组织化学检测

背景:深低温冷冻技术能够降低同种异体骨的免疫原性,对修复骨缺损具有重要意义。目的:观察深低温冷冻对骨材料中骨形态发生蛋白2表达的影响。方法:18只新西兰兔随机分为3组,深低温冷冻3个月组,深低温冷冻6个月组,新鲜骨对照组,取右侧胫骨中上1/3,分别于-80℃保存保存3个月,6个月及不保存,进行苏木精-伊红染色和骨形态发生蛋白2免疫组织化学染色。结果与结论:深低温冷冻后骨材料形态学,与新鲜骨差异不大;深低温冷冻3个月及6个月骨组织中骨形态发生蛋白2均有表达,但较新鲜骨降低。     

玻璃化法保存兔关节软骨的实验研究

目的观察玻璃化法保存兔关节软骨的效果。方法选取10只大白兔,软骨标本取材后,低温冷冻组5只和玻璃化保存组5只,分别通过台盼蓝拒染法检测兔关节关节软骨细胞存活率和MTT法测软骨细胞相对活性。结果玻璃化保存组兔关节关节软骨细胞存活率和软骨细胞相对活性均优于低温冷冻组,差异均有显著性(P<0.05)。结论玻璃化法保存兔软骨,软骨存活率高,软骨修复区的组织更接近正常软骨。     

快速冷冻与慢速冷冻条件下复合组织血管内皮的生物活性

背景:恢复良好血供对于复合组织保存及再植至关重要,但不同冷冻方法对血管活性影响不同。目的:比较快速冷冻与慢速冷冻方法对复合组织血管内皮活性的影响。方法:新西兰大白兔后肢分别进行快速冷冻与慢速冷冻,快速冷冻的兔后肢直接放入液氮中,慢速冷冻组经4℃,-20℃,-80℃冷冻后再投入到液氮中,各组依次保存12h,3d,7d后快速复温,并设对照组。所有新西兰大白兔后肢均经甲醛溶液固定后行苏木精-伊红染色及免疫组织化学染色检测各组血管内皮的病理变化。结果与结论:快速冷冻组和慢速冷冻组冷冻12h,3d,7d时兔血管组织形态评分均低于对照组(P<0.05)。快速冷冻组冷冻12h,3,7d时血管内皮组织血管内皮生长因子评分低于慢速冷冻组(P<0.05)。证实,慢速冷冻法能更好的维持复合组织中的血管内皮细胞的生物学活性。     

深低温冷冻骨的形态学及免疫组织化学检测

背景：深低温冷冻技术能够降低同种异体骨的免疫原性,对修复骨缺损具有重要意义。目的：观察深低温冷冻对骨材料中骨形态发生蛋白2表达的影响。方法：18只新西兰兔随机分为3组,深低温冷冻3个月组,深低温冷冻6个月组,新鲜骨对照组,取右侧胫骨中上1/3,分别于-80℃保存保存3个月,6个月及不保存,进行苏木精-伊红染色和骨形态发生蛋白2免疫组织化学染色。结果与结论：深低温冷冻后骨材料形态学,与新鲜骨差异不大;深低温冷冻3个月及6个月骨组织中骨形态发生蛋白2均有表达,但较新鲜骨降低。     

玻璃化冷冻法保存关节软骨

背景：同种异体骨软骨移植技术是治疗关节软骨缺损有效的方法之一,但由于移植物保存方法不理想,明显制约着该技术的临床应用。目的：探讨玻璃化冷冻法保存关节软骨组织的可行性和优越性。方法：切取成年猪骨软骨,制成约5mm×6mm（直径×长度）大小的圆柱形骨软骨块。以新鲜软骨组为对照,分别采用0.5mol/L甘油、1mol/L二甲基亚砜、1mol/L玻璃化溶液3种方法预处理软骨块,再行冷冻法保存软骨块8周,采用组织化学染色、免疫荧光染色观察并比较软骨细胞活性的变化。结果与结论：玻璃化溶液预处理组的关节软骨细胞存活率达到74.5%,明显高于甘油和二甲基亚砜预处理组,软骨基质成分仅少量丢失。3种方法相比较,玻璃化溶液预处理后慢速梯度降温冷冻保存法可以明显提高冻存关节软骨组织的活性。     

Differential activation of rabbit femoral arteries by aluminum fluoride and sodium fluoride

The effect of fluoride (NaF; 10 mM sodium fluoride plus deferoxamine to chelate contaminating aluminum) and fluoride plus aluminum fluorides (AlF; 10 mM sodium fluoride plus 20 microM aluminum chloride) on activation of rabbit femoral arteries was investigated. AlF and NaF produced large increases in stress (force/muscle cross-sectional area), but temporal changes were dissimilar, as were other indices of muscle activation. Stress produced by NaF developed slowly and only after a long delay of about 15 min, whereas stress produced by AlF developed rapidly after a delay of only about 5 min. NaF-induced contractions were more sustained than AlF-induced contractions. Both AlF and NaF increased the level of cross-bridge phosphorylation and the velocity of muscle shortening, but at comparable stresses, AlF produced greater increases than did NaF. AlF produced a large increase in lP production, whereas NaF produced a small increase. Also, AlF-induced stress was largely insensitive to inhibition by the calcium channel blocker, nifedipine (1 microM), whereas NaF-induced stress was largely inhibited by nifedipine. However, in tissues depleted of calcium, both agents produced potent contractions when CaCl2 was added back to the tissues (EC50 values for AlF, NaF, histamine, phenylephrine and KCl were, respectively, 0.057, 0.085, 0.11, 0.11 and 0.23 mM). AlF, but not NaF, strongly desensitized arteries to phenylephrine, causing a 73% reduction in the ability of phenylephrine to achieve maximum steady-state stress. These data suggest that fluoride contracted rabbit femoral arteries by stimulating L-type calcium channels, and that aluminum fluoride stimulated phospholipase C, producing additional muscle activation.     

Enhancement of Fas ligand-induced inhibition of neointimal formation in rabbit femoral and iliac arteries by coexpression of p35.

Adenovirus-mediated gene transfer of Fas ligand (FasL) inhibits neointimal formation in balloon-injured rat carotid arteries. Vascular smooth muscle (VSM) cells coexpressing murine FasL and p35, a baculovirus gene that inhibits caspase activity, are not susceptible to FasL-mediated apoptosis in vitro but are capable of inducing apoptosis of VSM cells that do not express p35. We reasoned that coexpression of p35 in FasL-transduced VSM cells in vivo would promote their survival, enhance FasL-induced apoptosis of adjacent VSM cells, and thereby facilitate a greater inhibition of neointimal formation. In balloon-injured rabbit femoral arteries, either Ad2/FasL/p35 or Ad2/FasL was infused into the injured site and withdrawn 20 min later. Both vectors induced a dose-dependent reduction (p < 0.05) of the neointima-to-media ratio when assessed 14 days later. However, Ad2/FasL/p35 exhibited a significantly greater inhibition of neointimal formation than Ad2/FasL. In a more clinically relevant model of restenosis, rabbit iliac arteries were injured with an angioplasty catheter under fluoroscopic guidance. Adenoviral vectors were delivered locally to the injured site over a period of 2 min, using a porous infusion balloon catheter. Twenty-eight days after gene transfer angiographic and histologic assessments indicated a significant (p < 0.05) inhibition of iliac artery lumen stenosis and neointimal formation by Ad2/FasL/p35 (5 x 10(11) particles per artery). The extent of inhibition was comparable to that achieved with Ad2/TK, an adenoviral vector encoding thymidine kinase (5 x 10(11) particles per artery) and coadministration of ganciclovir for 7 days. These data suggest that coexpression of p35 in FasL-transduced VSM cells is more potent at inhibiting neointimal formation and as such represents an improved gene therapy approach for restenosis.     

Disturbed blood flow induces erosive injury to smooth muscle cell‐rich neointima and promotes thrombus formation in rabbit femoral arteries

Summary. Background: Plaque erosion is a cause of atherothrombosis that preferentially occurs on smooth muscle cell (SMC)‐ and proteoglycan‐rich rather than lipid‐rich plaques. However, its underlying mechanisms remain unknown. Objective: To determine whether disturbed blood flow induces erosive injury and thrombus formation on SMC‐rich neointima. Methods: Three weeks after balloon injury, SMC‐rich neointima with increased tissue factor (TF) activity developed in rabbit femoral arteries that were narrowed with a vascular occluder to disturb blood flow after stenosis. Neointimal injury and thrombus formation were assessed at 15, 30, and 180 min after the vascular narrowing. Results: Endothelial detachment, platelet adhesion and neointimal cell apoptosis became evident at the post‐stenotic regions of all femoral arteries (n = 5) within 15 min of narrowing. Mural thrombi composed of platelet and fibrin developed after 30 min, and then occlusive thrombi were generated in three out of five vessels after 180 min. The identical vascular narrowing of normal femoral arteries also induced endothelial detachment with small platelet thrombi at post‐stenotic regions, but fibrin and occlusive thrombi did not develop. Computational simulation analysis indicated that oscillatory shear stress contributes to the development of erosive damage to the neointima. Conclusions: These results suggest that disturbed post‐stenotic blood flow can induce erosive injury in SMC‐rich plaques and promote thrombus formation that results in vascular events.     

兔股骨缺损模型的建立

目的:传统的兔桡骨骨缺损模型和胫骨骨缺损模型在骨的愈合过程中,不能排除与其紧密相临的尺骨或腓骨骨膜向骨缺损区成骨。为避免这种缺点,拟设计兔股骨1.5cm骨缺损模型,从而提供一种较为科学的骨缺损模型。方法:实验于2004-03/2005-12在解放军第一军医大学南方医院动物所完成。选取健康月龄6个月的新西兰大白兔6只,均制备左侧股骨中段长1.5cm的段缺性骨与骨膜缺损。从兔左后肢股骨前外侧纵切口,切开皮肤、皮下组织和深筋膜,沿股直肌与股外侧肌间隙锐性分开进入,不切开骨膜,于股骨前外侧放置已塑形好的4孔普通钢板,钢板预弯弧度5°～8°,以使钢板和股骨向前外凸的弧度相吻合。电钻钻孔后依次旋入4枚螺钉固定,可在两边两个螺钉之间各加用一根细钢丝环扎以增加牢固性。于钢板第2、3孔之间,以线锯锯断股骨一侧,用直尺测量股骨1.5cm长,并标记好另一端截骨线,线锯截断,并切除该段对应的骨膜,造成标准的1.5cm段缺性骨与骨膜缺损,生理盐水冲洗伤口,缝合后敷料包扎,术后肌注青霉素钠40万u预防感染。术后严密观察6只兔的精神状况、饮食、活动、伤口愈合情况。分别于术后6,12,18周各处死2只,大体观察骨缺损处的表面变化、内痂形成、两截骨端变化、骨缺损修复情况;摄左侧股骨正位X光片观察骨缺损愈合情况。结果:实验选取新西兰大白兔6只,全部进入结果分析。①术后动物一般情况:术后第1天所有兔的精神状况稍差,进食略减少,活动减少,术肢跛行明显,全身无皮疹及畏寒发热。2d后逐渐恢复正常活动,饮食增加,精神好转。②术后骨缺损区大体观察结果:术后6周骨缺损区有质较软的肉芽组织,无明显骨痂形成。术后12周有少量比较薄的骨痂,骨缺损区为软组织包裹。术后18周骨痂形成较前稍有增多,但骨缺损区仍无骨性连接,骨缺损未愈合。③术后骨缺损区X射线片观察结果:术后6周骨缺损区呈散在点状阻射影,骨缺损区清淅可见;术后12周骨缺损区周围近截骨端有小片状阻射影,骨缺损区呈透亮影;术后18周骨缺损区仍呈透亮影,两骨端硬化、髓腔封闭,骨缺损仍不能愈合。结论:采用股骨制备骨缺损模型,可避免膜性成骨的骨形成作用,神经、血管的解剖部位相对恒定,变异小,制作模型操作简单,且模型的统一性和可重复性好,能更好地观察骨缺损的修复效果。     

兔股骨缺损模型的建立

目的：传统的兔桡骨骨缺损模型和胫骨骨缺损模型在骨的愈合过程中，不能排除与其紧密相临的尺骨或腓骨骨膜向骨缺损区成骨。为避免这种缺点，拟设计兔股骨1．5cm骨缺损模型，从而提供一种较为科学的骨缺损模型。方法：实验于2004-03／2005-12在解放军第一军医大学南方医院动物所完成。选取健康月龄6个月的新西兰大白兔6只，均制备左侧股骨中段长1．5cm的段缺性骨与骨膜缺损。从兔左后肢股骨前外侧纵切口，切开皮肤、皮下组织和深筋膜，沿股直肌与股外侧肌间隙锐性分开进入，不切开骨膜，于股骨前外侧放置已塑形好的4孔普通钢板，钢板预弯弧度5&;#176;～8&;#176;，以使钢板和股骨向前外凸的弧度相吻合。电钻钻孔后依次旋入4枚螺钉固定，可在两边两个螺钉之间各加用一根细钢丝环扎以增加牢固性。于钢板第2．3孔之间，以线锯锯断股骨一侧，用直尺测量股骨1．5cm长，并标记好另一端截骨线，线锯截断，并切除该段对应的骨膜，造成标准的1.5cm段缺性骨与骨膜缺损，生理盐水冲洗伤口，缝合后敷料包扎，术后肌注青霉素钠40万u预防感染。术后严密观察6只兔的精神状况、饮食．活动、伤口愈合情况。分别于术后6，12，18周各处死2只，大体观察骨缺损处的表面变化．内痂形成．两截骨端变化、骨缺损修复情况；摄左侧股骨正位X光片观察骨缺损愈合情况。结果：实验选取新西兰大白兔6只，全部进入结果分析。①术后动物一般情况：术后第1天所有兔的精神状况稍差，进食略减少，活动减少，术肢跛行明显，全身无皮疹及畏寒发热。2d后逐渐恢复正常活动，饮食增加，精神好转。②术后骨缺损区大体观察结果：术后6周骨缺损区有质较软的肉芽组织，无明显骨痂形成。术后12周有少量比较薄的骨痂，骨缺损区为软组织包裹。术后18周骨痂形成较前稍有增多，但骨缺损区仍无骨性连接，骨缺损未愈合。③术后骨缺损区X射线片观察结果：术后6周骨缺损区呈散在点状阻射影，骨缺损区清淅可见；术后12周骨缺损区周围近截骨端有小片状阻射影，骨缺损区呈透亮影；术后18周骨缺损区仍呈透亮影，两骨端硬化、髓腔封闭，骨缺损仍不能愈合。结论：采用股骨制备骨缺损模型，可避免膜性成骨的骨形成作用，神经、血管的解剖部位相对恒定，变异小，制作模型操作简单，且模型的统一性和可重复性好，能更好地观察骨缺损的修复效果。     

Vasospastic myocardial infarction complicated with bilateral femoral arteries vasospasm

Coronary vasospasm is an infrequent cause of acute coronary syndrome. Additionally, femoral artery spasm is not frequently encountered clinically. Here we present a case of a patient with an acute ST segment elevation myocardial infarction, secondary to a documented right coronary artery vasospasm, complicated with left coronary artery and femoral artery vasospasm. Intravenous ultrasound showed calcification at the sites of spasm. This case report indicates that coronary vasospasm should be regularly considered as part of the work up of myocardial infarction.     

Functional and histological changes in rat femoral arteries by HIFU exposure

This study was an investigation of arterial contractility in response to high-intensity focused ultrasound (HIFU) and of histologic changes to the artery with various intensities of HIFU. We constructed a prototype HIFU transducer in combination with an imaging probe that provides color Doppler imaging and Doppler velocimetry. HIFU was applied through the skin to deep femoral arteries in left thighs of Sprague-Dawley rats; color images of the blood flow were used to aim the HIFU beam. Peak intensities used were 530, 1080, 2750 and 4300 W/cm2. The duration of each HIFU exposure was 5 s. HIFU was applied to five focal spots of each leg. These focal spots were aligned with a spacing of 1.0 mm so as to form a line across the artery. Blood flow occlusion was accomplished by HIFU at an intensity of 4300 W/cm2, but the flow continued with the lower intensities. Peak systolic velocities (PSVs) of blood flow as measured by Doppler velocimetry increased in the arteries to which HIFU had been applied at 1080 and 2750 W/cm2. The increase corresponded with HIFU intensity. Exposure to HIFU at 530 W/cm2 did not change the blood flow velocity. Histologic studies have demonstrated that exposure to HIFU at 2750 and 4300 W/cm2 leads to vacuolar degeneration and destruction of elastic fibers of the tunica media of the artery. Exposure at 1080 W/cm2 led to increased PSV, but did not induce histologic changes in the vessel wall. In conclusion, the response of the artery to HIFU varied with intensity. Vascular contraction without tissue degeneration occurred at low intensity; with increasing intensity, the tissue degeneration detectable in histology reduced the vascular diameter and, finally, at high intensity, the blood flow was occluded. Although these phenomena appeared to be mainly due to thermal effects, mechanical effects might have some role, particularly on vascular contraction.     

兔股骨三维生物力学模型的建立

背景：基于自编写的Matlab程序实现了对兔股骨图像边缘的识别。但鉴于模型的复杂性,在UG三维软件中建立股骨实体模型后导入ANSYS软件中,能否构建相应的结构模型？目的：构建兔股骨三维生物力学模型的方法。设计：随机对照观察。单位：北京理工大学生物力学实验室。材料：实验用1只雌性新西兰大白兔,兔龄1年,体质量2.6kg,。实验用ACTIS400/225型工业CT扫描机为美国BIR公司生产。方法：实验于2005-07/12在北京理工大学生物力学实验室完成。①股骨影像轮廓提取：实验兔麻醉后处死,分离股骨。将工业CT扫描图像转换成＊.bmp格式的图像文件,应用Photo shop图像处理软件,对原始图像进行对比度调整、平滑去噪等必要处理,以增强图像的可辨性和可分析性。再用磁性套索工具勾勒各层图像的内、外边界线,得到各层面股骨内、外轮廓曲线,采用CT扫描机对兔股骨进行扫描,自股骨头上端起,由近端向远端垂直于股骨纵轴行CT扫描,层间距为1mm。小转子下方第43层至股骨中段53层,由于形状比较规则,扫描层间距为2mm。共扫描87层,长度为9.9cm,输入计算机后经处理得到边界轮廓线,再通过自编程序,获取建模时所用的轮廓线坐标,将坐标数据输入建模软件,建立三维实体模型。②股骨有限元模型的建立：将UG中导出的＊.IGES文件,导入至ANSYS软件,自动生成股骨实体模型,利用ANSYS软件布尔操作中的减操作,得到有空腔的实体模型。主要观察指标：兔股骨结构模型建立情况。结果：①利用UG三维造型软件,读取第1层轮廓数据＊.dat文件,形成由多个数据点连接的自由曲线,依次读取第2层、第3层、第4层至第87层,形成兔股骨内、外轮廓的堆叠图。②采用自由网格划分法,应用ANSYS程序自动划分网格,生成有限元网格。网格划分后得到42221个节点及27768个单元。结论：实验模型真实模拟了兔股骨的解剖学形态。建立的三维生物力学模型为下一步通过有限元法确定振动对骨丢失影响的最佳参数奠定了实验学基础。     

Serotonin induces vasoconstriction of smooth muscle cell-rich neointima through 5-hydroxytryptamine2A receptor in rabbit femoral arteries

Summary.  Background:  Smooth muscle cell (SMC)-rich intima is a morphological feature of atherosclerotic lesions that is observed in eroded plaque and spastic arteries. Arteries with SMC-rich intima are susceptible to vasoconstriction or vasospasm against some vasoactive agents. Objective:  The present study evaluates the contribution of SMC-rich intima to thrombogenic vasoconstriction. Methods:  We established SMC-rich neointima by damaging rabbit femoral arteries using balloons and then measured the isometric tension of the femoral strips against 5-hydroxytryptamine (5-HT), adenosine diphosphate, adenosine triphosphate and thrombin. Results:  Among these agents, only 5-HT induced a hypercontractile response of the injured arteries with SMC-rich neointima, compared with non-injured arteries. Smooth muscle cells of both the neointima and media expressed 5-HT_2A receptor, and sarpogrelate, a selective 5-HT_2A receptor antagonist significantly inhibited the hypercontraction. Furthermore, 5-HT induced contraction of separated neointima and hypercontraction of separated media compared with non-injured media. Sarpogrelate and fasudil, a specific Rho-kinase inhibitor, significantly suppressed such contraction of both the neointima and media of injured arteries. Conclusions:  These results suggest that 5-HT plays a crucial role in thrombogenic vasoconstriction, and that SMC-rich intima as well as media directly contributes to the hypercontractile response of atherosclerotic vessels through the 5-HT_2A receptor and the Rho-kinase pathway.     

脂多糖增强芬太尼诱导离体兔肺动脉舒张反应

目的 探讨阿片受体激动剂芬太尼对正常及内毒素休克时肺动脉血管反应性的影响,从而指导临床用药.方法 应用血管环张力检测技术,观察芬太尼对正常及脂多糖(lipopolysaccharide,LPS)孵育的肺动脉血管环反应性的影响.结果 在正常肺动脉组,芬太尼终浓度(0.1、1、10、100 μmol/L)使去氧肾上腺素(Phenylephedrine,PE)预收缩的肺动脉舒张(EC50=1.699);在LPS孵育的肺动脉组,芬太尼终浓度(1、10、100 μmol/L)使PE预收缩的肺动脉舒张(EC50=2.496),芬太尼终浓度(0.1 μmol/L)对肺动脉并没有影响;LPS组与正常组对照比较,LPS组芬太尼使肺动脉舒张反应Emax增加,在小剂量芬太尼终浓度(0.1、1 μmol/L)时肺动脉的敏感度下降,在大剂量浓度(10、100 μmol/L)时却使其敏感度增加.结论 LPS可以增强芬太尼对肺动脉的最大舒张反应;并且LPS可使小剂量的芬太尼对肺动脉的敏感度下降,大剂量的芬太尼敏感度增加;LPS还可使芬太尼对肺动脉舒张反应的EC50增大.