静脉瓣膜的生物力学特性初探

本文通过不同部位静脉瓣膜的拉伸、滞后、压力松弛实验,表明静脉瓣膜的加载卸栽滞后现象和不同部位静脉瓣膜具有不同的抗张能力,作出对静脉瓣膜的生物力学性质的探索,为人造静脉瓣膜材料选择决定,提供参考指标。     

建立基于浸入边界有限元法的三维静脉瓣流固耦合数值模型

目的 探究静脉内血液与瓣膜之间的流固耦合动态过程和保证血液单向回流的生理机制。方法 基于浸入边界有限元法,结合人体下肢静脉医学图像及牛大隐静脉的解剖结构和尺寸,采用超弹性本构模型描述静脉瓣膜在生理条件下不可压缩、非线性和超弹性力学响应,构建静脉血管和静脉瓣膜的三维数值模型。结果 研究结果可视化地展示静脉动态运输血液的过程以及静脉瓣膜防止反流的功能机制,再现静脉内瓣膜运动和血液流动的周期性特点,讨论和量化了整个心动周期内的重要生理数据,包括静脉内血液的压力、流速和流量以及静脉瓣膜的开口面积、静脉瓣膜表面的应力和应变分布等。结论 三维流固耦合模型可数值再现静脉内生理动态过程,为进一步揭示静脉疾病相关机制提供重要的参考和指导意义。     

四肢静脉造影术的探讨

近代显微外科的进展,为修复创伤性软组织及骨骼缺损提供有利条件,尤其是带血管神经蒂的肌肉皮瓣移植术或移位术对整复外科具有重要意义。断肢再植的经验证明静脉回流对移植战败起关键作用。因之,从解剖学上研究四肢静脉的分布、直径及吻合网大小等具有一定意义。但静脉系统由于存在大量瓣膜,故静脉造影比     

(膕)静脉瓣膜的形态特点及其临床意义

目的:为临床诊断和治疗原发性下肢深静脉瓣膜功能不全和构建组织工程静脉瓣膜提供形态学基础.方法:将26例52侧成人朋静脉标本等分为远侧、中间、近侧1/3段,在手术显微镜下解剖和观察,用数控游标卡尺(精度0.01 mm)测量瓣膜相关数据,并对瓣膜进行Masson三色改良染色和H-E染色,以观察(月国)静脉瓣的组织构造.结果:(月国)静脉瓣膜数为(2.04±1.31)个,瓣膜游离缘主要为半月形(97.2%).瓣膜以双叶瓣为主(97.2%),其近侧1/3段和中1/3段以前后侧瓣为主(P＜0.05).瓣膜的腔面和窦面均覆着一层内皮细胞,其管腔面内皮细胞下存在数层弹力纤维,瓣膜主要由胶原纤维构成.结论:本文提供的胭静脉瓣的形态特征和数据将有助于临床朋静脉瓣膜相关疾病的诊治和构建组织工程静脉瓣.     

下肢深静脉瓣膜的应用解剖

在30具成人尸体上,对60侧股静脉,胸静脉、股深静脉、胫前静脉,56侧胫后静脉,58侧腓静脉的瓣膜进行了观察,深入研究了各段静脉瓣膜的出现率、数目、形态、分布和位置。单侧下肢深静脉瓣膜总数平均值为48.61个。绝大多数瓣膜为双叶瓣(99.34%±0.14%),极少数为单叶瓣(0.61±0.14%),三叶瓣罕见(0.03±0.03%)。双叶瓣大部分位于静脉的前、后壁(88.78±0.58%),少部分位于静脉的左、右壁(11.21±0.58%);单叶瓣位于静脉的后壁;三叶瓣位于静脉的右、后、右壁。     

心房内分泌肌细胞的分泌方式及其与神经、毛细血管关系的超微结构研究

本研究用透射电镜观察心房内分泌肌细胞在心脏不同容量负荷时的超微结构变化,以及其周围的神经、毛细血管的分布及类型。禁水或不禁水大鼠,在经股静脉注入生理盐水(20ml/kg体重)30～120秒内取右心耳。用鞣酸、戊二醛、锇酸法和戊二醛、锇酸法固定,观察到肌细胞特殊颗粒界膜与肌膜融合、开口和释放的全过程。有不同种类的神经终末存在于肌细胞旁。毛细血管为连续内皮型,与肌细胞关系密切。本实验结果提示,心房内分泌肌细胞主要以胞吐方式分泌心房利尿因子,并为心房利尿因子的转运及与神经支配的生理、生物化学研究提供了形态学资料。     

人心肌内静脉瓣分布与冠脉回流的关系

人心表面静脉存在瓣膜已被人们所公认。但是心室壁内静脉即心肌内静脉是否有瓣膜仍是一有待明确的问题。我们采用5例新鲜幼儿心脏,冠状窦插管后,逆行灌注浓度10%的ABS丙酮液。经腐蚀、冲洗、取材、干燥后,应用IB-3型真空喷镀仪镀金,在S-450型扫描电镜下观察。发现心肌静脉的铸型上存在瓣膜压迫。     

浅静脉-皮神经营养血管皮瓣的血供研究进展

90年代初 ,有几位国外学者重新研究了皮神经营养血管与皮肤血供的相互关系 ,发现围绕皮神经的营养血管对皮肤血供有重要作用 ,提出了神经皮瓣 (ｎｅｕｒｏｃｕｔａｎｅｏｕｓｆｌａｐ)的概念[1 ,2 ] 。最近 ,Ｎａｋａｊｉｍａ等[3] 发现 ,四肢浅静脉也有一套营养血管系统 ,这套血管系统与皮神经营养血管系统相似。这样 ,在有浅静脉、皮神经或浅静脉与皮神经伴行的部位 ,都可切取相应的营养血管皮瓣。因此 ,单纯用皮神经营养血管皮瓣的概念已不足以反映皮瓣血供的实质 ,有必要提出浅静脉营养血管皮瓣、浅静脉—皮神经营养血管皮瓣的概念。1　…     

大鼠心瓣膜神经支配

本文通过对32只大鼠心瓣膜进行胆碱酯酶组织化学法、乙醛酸诱发荧光法及P物质免疫组化方法的观察,获得心瓣膜胆碱能、肾上腺素能及肽能(SP)神经支配全貌。P物质免疫反应阳性神经纤维在房室瓣自瓣膜基部向下及自腱索向上进入瓣膜;在动脉瓣自附着缘进入瓣膜。该纤维的性质及走向提示SP免疫反应阳性神经纤维可能是感受血流动力学变化的传入神经。     

骨髓间充质干细胞联合可降解支架体外构建组织工程带瓣静脉（英文）

背景:临床上治疗慢性静脉功能不全的主要方法是静脉瓣膜修复及带瓣静脉段移植,但这些方法创伤较大,且带瓣静脉来源有限。组织工程学和再生医学在修复病变血管方面取得的进步,而以自体来源的内皮细胞为种子细胞的组织工程带瓣静脉也见于了报道,但存在排出反应。目的:构建一个有可自我更新、修复、类似天然瓣膜结构并具有功能的带瓣静脉。方法:麻醉取Beagle犬的骨髓获取骨髓间充质干细胞,采用密度梯度离心和贴壁法获取骨髓间充质干细胞,并进行细胞的传代、冻存复苏、流式细胞仪检测和定向诱导分化。采用热致相分离技术,以聚(乳酸-乙醇酸)共聚物为基材,利用自制带瓣静脉模具制备三维组织工程带瓣静脉支架,制备组织工程带瓣静脉支架,并研究其形态结构。将骨髓间充质干细胞种植在支架上构建可降解的带瓣静脉,在体外培养2周。结果与结论:扫描电镜观察显示支架孔隙率高。培养的细胞符合骨髓间充质干细胞的形态特征,培养的细胞大部分表达CD29和CD44,不表达CD34和CD45。细胞毒性实验显示支架无毒性,有利于细胞增殖和迁移。将细胞种植在支架表面上培养后可形成单层细胞层。体外实验验证细胞支架复合物的瓣膜有一定的开闭功能。利用三维聚(乳酸-乙醇酸)共聚物支架和骨髓间充质干细胞可成功构建组织工程带瓣静脉,组织工程带瓣静脉将有可能作为静脉瓣膜的的替代物治疗静脉瓣膜疾病。     

Variations in atrioventricular valve innervation in four species of mammals

In this series of studies, the innervation patterns of whole-mount preparation of bicuspid and tricuspid valves were studied by light microscopy in the mouse, rat, guinea pig, and opossum. The acetylcholinesterase-positive networks of nerve fibers showed many similarities in the basic patterns of valve innervation in all of the species studied, but several interspecies variations were observed. The basal zone of the valve adjacent to the fibromuscular atrioventricular ring displayed the most dense plexus of nerves, with acetylcholinesterase-positive fibers being seen across the width of the valve. In the intermediate zone of the valve, less dense plexuses of nerve fibers were found; and these were more numerous in the cuspal areas and less numerous in the intervening commissural areas. In the distal portions of the valve, nerve networks arborized extensively, with some of their nerve fibers extending toward the chordae tendineae and the free edges of the valve cusps. Only in the guinea pig and opossum did these fibers reach the free margin of the valve cusp, where they either ended directly as free nerve endings or lay parallel to the free edge of the cusp, often running between adjacent chordae tendineae. Although the patterns of innervation were similar in both bicuspid and tricuspid valves, the innervation density of the bicuspid valve was greater than that of the tricuspid valve for each species examined. A distinguishing feature of guinea pig and opossum tricuspid valves was that their chordae tendineae were relatively more prominent and more densely innervated than the bicuspid chordae tendineae. Free nerve endings with no light microscopic evidence of specialization were present throughout the bicuspid and tricuspid valves of all species studied. Some nerve endings in the opossum showed evidence of specialization, with brush-like arborizations leading to presumed free terminals seen chiefly in the distal zone of the valve cusps. Although some general tendencies were apparent, we have demonstrated that interspecies heterogeneity exists in the terminal networks of the atrioventricular valves of mouse, rat, guinea pig, and opposum. In spite of the questions raised regarding the significance of valve innervation in light of the success of valve prostheses, there is relatively high morbidity and mortality associated with heart valve replacement, partly due to deterioration in ventricular function. We and other investigators have reported that valvar nerves extend to the chordae and papillary muscles, varying with valve and species. This anatomical information about normal valves helps to lay the foundation for future studies of the role of valve innervation in the regulation of cardiac function and dysfunction. Such knowledge should be applicable for the control and management of myocardial infarction, valve disease, valve replacement, valvuloplasty, cardiac transplantation, administration of drugs, etc.     

Electron microscopic research on the venous valves of the lower extremities in varicose veins

Electron microscopy of the venous valves in varicose disease shows that dystrophic changes develop on the external and internal surfaces of the valve cusps. Endotheliocytes on the external surface are located longitudinally in relation to valvular axis and on the internal surface they are perpendicular to it. Fragments of the elastic membrane, collagen fibres and smooth muscle cells are seen under the endothelial lining. Endothelium actively regulates proliferative processes of smooth cells secreting the so-called "growth factor of endothelial origin". The development of venous valve pathological changes in varicose disease is accompanied by endothelial damage, disturbance of morphofunctional state of smooth muscle cells and intercellular substance of the vascular wall.     

Morphological and clinical aspects of scapular fasciocutaneous free flap transfer for treatment of venous insufficiency in the lower extremity

We have recently shown that free scapular fasciocutaneous flaps transferred to the lower extremities of patients with chronic venous insufficiency and cutaneous ulcers have resulted in improvement in venous refilling times measured by photoplethysmography in the flap areas and that recurrent ulceration does not recur for up to 7 years. We hypothesized that the transferred flaps contained valves in their microvascular bed, which facilitated venous return, and using scanning electron microscopy of vascular corrosion casts and light and transmission electron microscopy of tissue sections prepared from human dorsal thoracic fascia, we showed that valves were most abundant in veins with a luminal diameter of 30–120 μm (59.3% of 905 valves). The depth of these valves increased with venous diameter, but the size of valve sinuses was not different for individual valves. Except for veins >1,000 μm in diameter, there was no significant difference in the number of valves in different parts of an individual flap or between different flaps. Most valves were bicuspid; only in the vein Category 30–120 μm were unicuspid valves encountered. Valves were sometimes located in series in a short segment of a vein; occasionally they were found at the merging of two veins. Transmission electron microscopy showed that valve leaflets had collagen fibers that ascended toward the tip of the leaflet and were occasionally accompanied by elastic fibers. Myofibroblasts were regularly present in the valve leaflets. The present report reviews and updates these anatomic data about the human scapular region, focusing on venous valvular microstructure, and suggests that the high number of smaller-size valves contributes to improved hemodynamic of the leg and thus the clinical success of free scapular flaps used to treat cutaneous ulcerations in the lower extremity. Clin. Anat. 11:38–46, 1998. © 1998 Wiley-Liss, Inc.     

Micro-venous valves in the superficial veins of the human lower limb

It is commonly believed that venous valves are not present in veins smaller than 2 mm in diameter. Venous valves, however, have been identified recently in small veins in several regions of the body. This study was undertaken to determine the size distribution of venous valves in the human lower limb micro-venous circulation. Vascular casts were made from six adult lower limbs and the sampled areas were viewed by scanning electron microscopy. In total, 2,376 valves were identified from 410 cm(3) of subcutaneous tissue. The vast majority (94%) of the valves were in veins less than 300 microm in luminal diameter, with 65% of the valves present in venous channels less than 100 microm in luminal diameter. The smallest valves identified were present in venous channels 18 microm in diameter. All valves were bicuspid and often associated with a tributary. Endothelial cells on the vein wall not associated with a valve were fusiform and arranged parallel to the long axis of the vessel, however, the endothelial cells on the luminal and valve sinus surfaces of the cusp were more polyhedral in shape and showed no obvious pattern of alignment. This study provides direct evidence to show that small superficial veins of the human lower limb do contain abundant venous valves and, for the first time, shows that the majority of these valves are present within venous channels less than 100 microm in luminal diameter.     

Development of a prosthetic venous valve

The pathology of thrombophlebitis primarily results from the obliteration of venous valves in the lower extremities. The objective of this study was to develop a prosthetic venous valve that could be implanted in the human femoral system to ameliorate the deleterious effects of thrombophlebitis. Prosthetic venous valves were produced from two materials: Pellethane valves were fabricated from a dip-casting process; umbilical vein valves were produced by a fixation process. The valves were evaluated as implants within the external jugular veins of 10 research dogs. Each animal was implanted with one Pellethane valve in one external jugular vein and one umbilical vein venous valve in the contralateral jugular vein. Each valve was positioned over a stainless-steel cylinder that had been implanted into the jugular veins in such a manner that there existed no blood-cylinder interaction. Patency of the valves was determined by X-ray venography at 24, 48, and 72 h and at 5 and 8 days postoperatively. All of the umbilical vein venous valves were occluded by the end of 48 h, whereas two of the Pellethane venous valves remained patent for at least 5 days but were occluded at 8 days. The results of this study suggest the possibility of success of Pellethane valve implants in the venous circulation and indicate future directions for study.     

The atrioventricular valves of the guinea-pig. I. A light microscopic study

The atrioventricular valves contain dense plexuses of adrenergic nerve fibers, derived from atrial and ventricular sources. Most of the adrenergic terminals are located in the lower third of the cusps. This region, which contains adrenergic terminals and acetylcholinesterase-positive nerve endings is devoid of muscle fibers and blood vessels. The acetylcholinesterase-positive endings may be sensory; and norepinephrine released from the adrenergic terminals may influence their performance. In the mitral valve, the atrial adrenergic plexus is separated from the ventricular plexus by a narrow zone that is free of adrenergic nerves. In most other respects the innervation, musculature and vascular supply of the mitral valve is similar to that of the tricuspid valve. Each valve has an intrinsic skeleton. This is made up of collagenous “ribs” that pass up from the chordae tendineae and fan out in the cusps. “Ribs” from adjacent chordae overlap and interweave, forming a complex support system. The musculature of the valves is complex and seems to have several functions. The annular muscle around the valve orifice may act as an atrioventricular sphincter, while offshoots that insert into the collagenous “ribs” of the cusp may assist the papillary muscles in maintaining tension on the cusps. The meshwork of muscle fibers between “ribs” may prevent ballooning of the cusps during systole. We found no consistent association between valvar muscles and nerves. Blood vessels are restricted mainly to the upper muscular part of the cusps, although a few capillary loops descend into the midzone of the cusps.     

自发性高血压大鼠心瓣膜上含神经肽Y和含降钙素基因相关肽神经的变化

用免疫组织化学（ＡＢＣ）方法，观察了含神经肽Ｙ（ＮＰＹ）、降钙素基因相关肽（ＣＧＲＤ）神经在自发性高血压大鼠（ＳＨＲ）心瓣膜分布的变化。结果表明，在ＳＨＲ二尖瓣、三尖瓣上含ＮＰＹ、含ＣＧＲＰ神经的密度，和对照Ｗｉｓｔａｒ－Ｋｙｏｔｏ（ＷＫＹ）大鼠相比较，无明显差异。但ＳＨＲ二尖瓣及三尖瓣含ＮＰＹ神经的Ｒ值，即心壁和乳头肌两个来源的含肽神经相延续所在的腱索数目与本片瓣膜上的总腱索数的比值，大于ＷＫＹ大鼠；而ＳＨＲ心瓣膜含ＣＧＲＰ神经的Ｒ值和ＷＫＹ大鼠无差异。本文对ＳＨＲ心瓣膜上含ＮＰＹ和含ＣＧＲＰ神经的变化作了讨论。     

血管加压素免疫反应神经纤维也存在于中国树鼩垂体门微静脉管壁内

采用ABC免疫组化和DAB／H2O2／Ni加强技术以及兔抗血管加压素血清，观察了血管加压素免疫反应神经纤维在中国树垂体门脉系统的门微静脉壁内的存在。证明此纤维呈细丝状，在门微静脉壁内呈环行密集分布，可能呈螺旋形走向，纤维间界限不清，有的地方可见血管内皮细胞内含有血管加压素免疫反应产物。空白对照试验和抗催产素血清对照试验的结果表明；门微静脉壁内的着色反应为特异性的血管加压系免疫反应。本文讨论了门微静脉壁内血管加压素免疫反应神经纤维的来源、去向和与垂体前叶内其它肽能神经纤维的关系。