肝素化医用高分子抗凝管的研究

肝素经低温等离子体接枝处理固定在医用高分子管内壁，获得了内壁光滑的且具有抗凝血功能的新颖材料。经凝血时间（ＣＴ）和凝血因子（ＫＰＴＴ、ＰＴ、ＴＴ）时间的测定，这种抗凝管具有显著的抗凝血功能，并且管壁上固定着的肝素不脱落，鼠血流经抗凝管后２４小时以上仍不会形成血栓，切口处也不渗血。经接触角测定和复钙时间测得，氩等离子体轰击并完成肝素接枝上高分子表面的最佳合成时间是１２秒。     

血管通道对婴幼儿连续静脉血液过滤的影响

在连续动静脉血液过滤中,通过过滤器的血流是关键。血流量主要取决于动静脉压力梯度和血管通道内径。对于婴幼儿,血管通道在动静脉血液过滤中是主要问题。我们把短的18～20规格导管插入到幼儿挠动脉或肱动脉和颈内静脉,测得平均血液流量为3.5±2.2毫升/分钟和超滤率为1.3±0.3毫升/分钟。同样,我们放置4或5号法式导管到儿童股脉管,测得平均血液流量范围为18.5～63.6毫     

动脉分支和血流分配的定量分析

目的 详细分析动脉分支角和血管半径的关系。方法 运用生物学中的基本原理和方法进行分析。结果 动脉分支的分支角和血管半径有关，子管半径（r)和母管半径（r0)之比（r/r0)越小，分支角（θ)越大，cosθ=r/r0。动脉分支处的子管中的平均血流速度（v)与子管半径成正比，与母管中平均血流速度（v0)的关系是v=v0cosθ。用子管半径越小，子管中的红细胞压积越低的结果，解释了血液的血浆撇取效应。结论 血管不仅是血液输运器官，也是血流分配器官和红细胞分配器官。     

下肢常用皮瓣的应用解剖学要点

股前外侧皮瓣 一、血管蒂 旋股外侧动静脉降支及其分支(图1),属于肌皮血管穿支型血管(1)。 动脉:旋股外侧动脉降支发出4—9条肌皮动脉穿支(2)。第一肌皮动脉上方3cm处,降支的外径2.1(1.1～2.8)mm。 静脉:在旋股外侧动脉降支的两侧有同名伴行静脉,外径分别为2.3mm和1.8mm。 二、神经蒂 股外侧皮神经(图2),     

老年大鼠后肢高血流剪切力诱导的侧支血管生长及其与血管生成素-1表达的关系

目的:检测老年大鼠后肢高血流剪切力诱导的侧支血管生长情况及其与血管生成素-1(Ang-1)表达的关系。方法:实验组取12只老年健康SD大鼠,左侧行股动静脉单纯分离,右侧行股动静脉吻合术,在1周与4周时间点分别处死6只大鼠,采用血管造影与共聚焦免疫荧光术分别观察侧支血管生长情况及Ang-1在血管处的表达情况,正常组3只大鼠用作正常对照组。结果:正常对照组的侧支血管生长与假手术侧无明显差异,但吻合侧的侧支血管生长明显增加,且4周组吻合侧的血管生长多于1周组。正常对照组的血管Ang-1表达与假手术组无明显差异,仅在血管外膜及部分中膜存在表达;1周组吻合侧的Ang-1不仅在原有表达区域明显表达增加,且在内皮细胞处也有所表达;4周组吻合侧Ang-1在血管各层均明显存在高表达。与假手术侧相比,吻合侧Ang-1表达增加,差异具有统计学意义;4周吻合侧的Ang-1荧光强度较1周吻合侧明显增加,其差异也具有统计学意义。结论:老年大鼠后肢高血流剪切力模型可以诱导侧支血管的生长,且与相应部位血管Ang-1表达的增长呈正相关。     

膨体聚四氟乙烯人工血管表面肝素固化替代犬下腔静脉的表面抗凝血性能

背景：各种类型人工血管植入机体静脉后,由于血液与人工血管材料表面的不相容性和静脉内血流慢、压力低等原因,极易导致血管腔内血栓形成。 目的：观察膨体聚四氟乙烯人工血管表面固化肝素后代替犬下腔静脉的表面抗凝血性能和长期通畅效果。 方法：将壳聚糖分子中引入光敏基团后,通过光化学固定至膨体聚四氟乙烯材料表面,在酸性条件下将肝素以离子键形式接枝到壳聚糖上,在膨体聚四氟乙烯人工血管表面形成光滑的肝素层。以固化肝素的膨体聚四氟乙烯人工血管与未处理膨体聚四氟乙烯人工血管间置代替犬下腔静脉,检测其抗凝血性能。 结果与结论：固化肝素的膨体聚四氟乙烯人工血管植入后2周、1个月人工血管内壁光滑,仅有少量附壁血栓形成,无充盈缺损,吻合口无狭窄,通畅率达100%;未处理膨体聚四氟乙烯人工血管植入后1周即显示人工血管内附有大量血栓成分,完全堵塞,形成丰富的侧枝。说明固化肝素膨体聚四氟乙烯人工血管是一种理想的下腔静脉替代物。     

超声造影在增强原位肝移植后肝脏血管显像中的作用

目的　评价超声造影与彩色多普勒在观察原位肝移植后供肝血管血供情况中的作用。方法　分析了原位肝移植后的 4 7例患者 ,在注射利声显造影剂前后 ,用彩色多普勒分别观察肝脏血管的血供情况 ,并按供肝血管的血供情况进行评分等级分析 ,评分根据彩色多普勒检测血流信号的多少分 0～ 4级。结果　门静脉的血供情况在使用利声显造影前后无明显变化。肝动脉在使用利声显造影剂前 ,4 7例患者中彩色多普勒只检测到 39例患者的血流信号。应用造影剂后 ,4 6例患者的肝动脉均检测到血流信号 ;另 1例患者的肝动脉未检测到血流信号 ,后经血管造影确诊为…     

下肢动脉血管再通修复重建对下肢动脉缺血导致创面修复的影响

目的 探讨下肢动脉血管再通修复重建对下肢动脉缺血导致创面修复的影响。方法 2003年6月至2007年5月对226例下肢动脉缺血导致创面的患者分为未行下肢动脉血管再通修复重建的患者118例和行下肢动脉血管再通修复重建的患者（包括经皮腔内血管成形修复及支架置入术、人工或自体血管搭桥动脉旁路移植术、动脉血管内膜硬化斑剥脱血管成型修复、动脉血管切开取栓和大网膜移植血流再通重建术）108例共两组，采用超声彩色多普勒和选择性血管造影进行检查是否存在下肢动脉的缺血，分析创面的愈合情况（包括创面愈合时间、截肢率和复发率等）。结果 （1）226例下肢动脉缺血形成的创面中足部感染或溃疡197例（87％，197／226），小腿皮肤慢性感染和溃疡29例（13％，29／226）。创面〈1cm者59例（26％，59／226），创面1～2cm者77例（34％，77／226），创面2～5cm者63例（28％，63／226），创面〉5cm者27例（12％，27／226）；（2）226例行超声彩色多普勒检查阳性结果201例（阳性率89％，201／226），其中完全闭塞者48例（24％，48／201），重度狭窄者71例（35％，71／201），中度狭窄者82例（41％，82／201）；（3）行选择性血管造影者192例，检测阳性结果为167例（87％，167／192），其中髂总动脉＋髂外动脉＋股动脉闭塞或狭窄者23例（14％，23／167），髂外动脉＋股动脉闭塞或狭窄者39例（23％，39／167），股动脉＋腘动脉闭塞或狭窄者58例（35％，58／167），腘动脉下动脉血管闭塞或狭窄者47例（28％，47／167）；（4）在108例下肢动脉血管再通修复重建的患者中，经皮腔内血管成形修复再通重建（PTA）及支架置入术32例（30％，32／108），人工或自体血管搭桥动脉旁路移植血管修复再通重建（髂-股动脉、髂-腘动脉、股-股动脉、股-腘动脉、股-胫前或后动脉）术36例（33％，36／108），动脉血管内膜硬化斑剥脱血管成型修复再通重建术25例（23％，25／108），动脉血管切开取栓再通术11例（10％，11／108），大网膜移植血流再通重建术4例（4％，4／108）；（5）行和未行下肢动脉血管再通修复重建的患者相比，创面愈合的天数平均缩短（25±3）天（P〈0．05），行下肢动脉血管再通修复重建的患者截肢率为7％（7／108），复发率为8％（8／108），未行下肢动脉血管再通修复重建的患者截肢率为14％（16／118），复发率为27％（32／118）。结论 在下肢动脉缺血导致下肢或足部创面的愈合的过程中，下肢动脉血管再通修复重建起非常关键的作用。     

组织工程小血管支架移植于异种动物的血流和管壁变化

背景：脱细胞的异种小血管支架已被初步去除引起排斥反应的异种抗原。 目的：将脱细胞的Wistar大鼠尾动脉支架移植于日本大耳白兔耳血管间,观察移植后血流和管壁变化。 方法：15只Wistar大鼠每只取2条长2.50 cm的尾动脉干共30条作为异种小血管,15条直接作为供体尾动脉干,另15条经1%聚乙二醇辛基苯基醚脱细胞处理作供体组织工程小血管支架。受体为15只日本大耳白兔左右耳背面中央动脉。在外科显微镜下,兔中央动脉近侧断端采用全层套叠吻合法套入供体血管近侧腔内,远侧断端按常规端端吻合。采用勒通试验法和常规血管管腔血液、管壁染色法,连续观察血管内血流状况。 结果与结论：血管移植后的即刻通畅率达100%。异种小血管支架血液通畅最长时间为46 h 47 min,长于异种小血管移植(14 h),两组远侧的端端吻合区首先出现血流不畅;套叠区小血管支架与中央动脉外膜间由蒂状结缔组织相连。第10天,小血管支架可见内膜纤维组织仍然呈梳头状整齐排列,未见细胞附着;在术后第100天,仍保留着血管支架的完整性。结果提示,脱细胞异种小血管支架可作为血管移植物吻合于动物宿主内,异种小血管支架移植的套叠式吻合法优于经典的端端吻合法。     

建立椎动脉急性血栓栓塞犬模型:微球囊导管临时隔截取栓

背景:为了避免机械取栓术中血栓脱落造成远端栓塞,作者以期运用微球囊临时隔截的方法来建立防止血栓脱落的保护装置。目的:探讨采用微球囊临时阻断动脉血流并隔截栓塞段保护下行机械碎栓、吸栓联合溶栓治疗超急性脑梗死的安全性和可行性。方法:Beagle犬10只在全身麻醉下经股动脉插管将微球囊导管送至优势侧椎动脉内并充盈球囊临时阻断血流,经微导管注入自体血栓建立椎动脉血栓栓塞模型,按治疗方法均分为2组,对照组采用单纯支架取栓,实验组采用微球囊导管临时阻断血流并隔截靶动脉后行机械碎栓吸栓联合药物溶栓。两组治疗后均行数字减影血管造影复查栓塞椎动脉再通状况;采用血栓性脑缺血血流分级进行血流动力学评估。造模前及取栓后12 h行磁共振弥散加权成像。建模后12 h行核磁共振成像检查后处死动物行病理检查,统计两组血管再通成功率及并发症。结果与结论:10只beagle犬的优势侧椎动脉均成功出现血栓栓塞。对照组中2只犬椎动脉完全再通,3只犬椎动脉部分再通,其中1只犬椎-基底动脉与颅内动脉中可见多处小点状充盈缺损,颅内动脉显影差,对比剂返流,建模后12 h磁共振弥散加权成像示左侧颞顶叶稍高信号影,病理检查示左侧大脑颞叶动脉腔内见血栓形成。实验组中5只犬椎动脉均完全再通,未见脑梗死。实验组血管再通率高于对照组(P0.05)。结果证实,在急性脑动脉栓塞血管再通中采用微球囊导管临时阻断血流并隔截靶动脉保护下机械碎栓、吸栓联合尿激酶溶栓,可有效防止小栓子脱落栓塞远端动脉,安全有效。     

Muscle recovery after repair of short and long peripheral nerve gaps using fibrin conduits

Peripheral nerve injuries with loss of nervous tissue are a significant clinical problem and are currently treated using autologous nerve transplants. To avoid the need for donor nerve, which results in additional morbidity such as loss of sensation and scarring, alternative bridging methods have been sought. Recently we showed that an artificial nerve conduit moulded from fibrin glue is biocompatible to nerve regeneration. In this present study, we have used the fibrin conduit or a nerve graft to bridge either a 10 mm or 20 mm sciatic nerve gap and analyzed the muscle recovery in adult rats after 16 weeks. The gastrocnemius muscle weights of the operated side were similar for both gap sizes when treated with nerve graft. In contrast, muscle weight was 48.32 ± 4.96% of the contra-lateral side for the 10 mm gap repaired with fibrin conduit but only 25.20 ± 2.50% for the 20 mm gap repaired with fibrin conduit. The morphology of the muscles in the nerve graft groups showed an intact, ordered structure, with the muscle fibers grouped in fascicles whereas the 20 mm nerve gap fibrin group had a more chaotic appearance. The mean area and diameter of fast type fibers in the 20 mm gap repaired with fibrin conduits were significantly (P < 0.01) worse than those of the corresponding 10 mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. Furthermore, the 10 mm gaps repaired with either nerve graft or fibrin conduit showed similar muscle fiber size. These results indicate that the fibrin conduit can effectively treat short nerve gaps but further modification such as the inclusion of regenerative cells may be required to attain the outcomes of nerve graft for long gaps.     

A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers

Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may represent a promising biomaterial for use in bioengineered peripheral nerve repair.     

A synthetic oxygen carrier in fibrin matrices promotes sciatic nerve regeneration in rats

Tissue-engineering nerve conduits have been studied for a long time in bridging large nerve defects. However, the low oxygen availability within the nerve conduits, which results in death of migratory Schwann cells (SC) or loss of the newly formed tissue’s function, is still an obstacle for axonal regeneration. Thus, it was hypothesized that an oxygen-enriched conduit would enhance axonal regeneration and functional recovery in vivo. To address this issue, perfluorotributylamine (PFTBA) enriched fibrin hydrogel was prepared and injected into collagen–chitosan conduits. The conduit containing PFTBA-enriched fibrin hydrogel was then used to bridge a 12-mm sciatic nerve defect in rats. The control rats were bridged with collagen–chitosan conduits filled with fibrin matrices without PFTBA. It was found that axonal regeneration and functional recovery in the combined PFTBA group were significantly higher than those in the control group without PFTBA. Further investigations showed that the mRNA and protein levels of S-100, brain-derived neurotrophic factor and nerve growth factor were enhanced by PFTBA at 1 and 3 weeks after surgery. However, the mRNA and protein levels of vascular endothelial growth factor were in a similar range between the combined PFTBA group and the control group without PFTBA. In addition, immunohistochemical results showed that the morphological appearances of regenerated nerve and survival of SC were enhanced by PFTBA at 4 and 12 weeks after surgery. In conclusion, PFTBA-enriched nerve conduit is capable of enhancing axonal regeneration, which provides a new avenue for achieving better functional recovery in the treatment of nerve defect.     

神经导管修复周围神经损伤的研究进展

随着神经修复技术特别是显微外科的发展，神经损伤修复的质量有了进一步的提高；利用神经导管桥接神经断端以实现修复周围神经损伤是目前的一个研究热点。本综述了神经导管修复周围神经损伤的发展历史，分析比较了非神经组织、非生物降解材料、可生物降解材料神经导管在神经损伤修复中的效果，讨论了导管的形态及导管内微环境对神经再生的影响。     

Early clinical outcomes of right ventricular outflow tract reconstruction with small caliber bovine jugular vein conduit (Contegra<Superscript>®</Superscript>) in small children

This study reviewed early clinical outcomes of right ventricular outflow tract reconstruction with Contegra^® valved conduits in pediatric patients. Between April 2013 and July 2014, thirteen pediatric patients underwent right ventricular outflow tract reconstruction with Contegra valved conduits. The size of the implanted conduits were 12 mm in 5 patients, 14 mm in 3, 16 mm in 3, and then 2 patients were implanted with bicuspidized conduits for downsizing the conduit to 9 and 10 mm in each. Follow-ups were completed in all patients. One conduit was explanted 7 days after a neonatal biventricular repair for Ebstein’s anomaly and pulmonary atresia, timed to be at the point of conversion to a single ventricular palliation. Among the 5 patients who developed significant pulmonary insufficiency and/or conduit stenosis, 3 patients exhibited persistent pulmonary hypertension. Both the bicuspidized conduits resulted in early pulmonary insufficiency. One patient implanted with a ring-supported conduit developed coronary artery stenosis, caused by suppression between the ring of the implanted conduit and the annulus of the mechanical vale. Although the small caliber Contegra valved conduit might be an alternative to RVOT reconstruction, the indication should be carefully considered. More than mild pulmonary hypertension, and low body weight at operation of less than 3.0 kg caused early conduit dysfunction.     

新型推板式左心辅助血泵的流场试验

报告了Z-4型推板式左心辅助血泵的结构以及进行流场试验的方法。试验结果表明，在充盈期，流体在心室内形成一个大旋涡，这个旋涡形成是以切线方向流入的模拟液与圆形血室内壁相互作用的结果，最大线速度(125cm／s)产生在进口管内瓣膜的大口一侧。在排血期，旋涡中心往出口管方向偏移，最大线速度(120cm／s)出现在出口管内。血室内流动状况良好，无滞流，无紊流，血液对血室内壁有良好的洗刷效应，血室内壁不易形成血栓，该血泵形状设计是比较合理的。     

Functional recoveries of sciatic nerve regeneration by combining chitosan-coated conduit and neurosphere cells induced from adipose-derived stem cells

Suboptimal repair occurs in a peripheral nerve gap, which can be partially restored by bridging the gap with various biosynthetic conduits or cell-based therapy. In this study, we developed a combination of chitosan coating approach to induce neurosphere cells from human adipose-derived stem cells (ASCs) on chitosan-coated plate and then applied these cells to the interior of a chitosan-coated silicone tube to bridge a 10-mm gap in a rat sciatic nerve. Myelin sheath degeneration and glial scar formation were discovered in the nerve bridged by the silicone conduit. By using a single treatment of chitosan-coated conduit or neurosphere cell therapy, the nerve gap was partially recovered after 6 weeks of surgery. Substantial improvements in nerve regeneration were achieved by combining neurosphere cells and chitosan-coated conduit based on the increase of myelinated axons density and myelin thickness, gastrocnemius muscle weight and muscle fiber diameter, and step and stride lengths from gait analysis. High expressions of interleukin-1β and leukotriene B4 receptor 1 in the intra-neural scarring caused by using silicone conduits revealed that the inflammatory mechanism can be inhibited when the conduit is coated with chitosan. This study demonstrated that the chitosan-coated surface performs multiple functions that can be used to induce neurosphere cells from ASCs and to facilitate nerve regeneration in combination with a cells-assisted coated conduit.     

外消旋聚乳酸/神经生长因子缓释导管的体内降解研究

目的：研究外消旋聚乳酸／神经生长因子缓释导管（PDLLA／NGF）的降解性能，为修复神经缺损提供依据。方法：制作PDLLA／NGF缓释导管并用于桥接大鼠坐骨神经缺损，术后1、2、3月分别行导管的大体观察和电镜检查。结果：术后大体观察及电镜检查发现，PDLLA／NGF缓释导管能在大鼠体内随时间延长逐步降解，内层降解比外层速度快，到3月时导管外形仍保持完整，再生神经已顺利通过导管腔，无压迫及疤痕形成。结论：PDLLA／NGF导管在大鼠体内降解时间超过3月，能提供缺损神经再生所需的时间，为神经再生提供良好的微环境。     

自体腹膜管道替代血管在冠状动脉搭桥手术中的实验应用

目的 采用实验犬的腹膜片制作腹膜管道替代冠状动脉搭桥手术中的传统移植血管,希望为冠状动脉搭桥提供一种理想的血管替代物.方法 随机选用杂种成年犬10头,雌雄不限,麻醉后气管插管行机控呼吸.所有犬经旁正中切口达腹直肌鞘后层取腹膜片,制成腹膜管道在非体外循环下行主动脉与右冠状动脉主干搭桥.采用电磁血流量计测量搭桥前后腹膜管道的血流通畅度.术毕记录实验犬的早期存活比例,饲养至实验结束处死动物,光镜下观察HE染色腹膜管道的病理变化.结果 实验犬的早期死亡比例为10%(1/10),腹膜管道的血流通畅,冠状动脉搭桥手术前后实验犬右冠状动脉的血流量分别为(126±13)、(117±14)ml/min,差异无统计学意义(P>0.05).腹膜管道的组织学形态改变良好,光镜下,未见腹膜管道瘤样扩张,无明显纤维疤痕形成,腹膜管道弹力纤维结构完好,无断裂,腹膜管道与血管吻合口附近有血管内皮细胞衍生.结论 在非体外循环下采用腹膜管道替代传统的移植血管行冠状动脉搭桥创伤小,实验犬存活比例高,冠状动脉血供效果令人满意,有希望成为理想的血管移植替代物.