不同段脐带静脉组织结构的定量分析及其临床意义

目的：对不同段脐带静脉的几何形态和显微结构成分的比较，为脐带静脉移植的临床应用提供形态学依据。方法：采用自然分娩正常胎儿脐带静脉20例，常规石蜡包埋、切片。用HE法、weigert法、苯胺蓝法及桔黄G法分别染组织结构、弹性纤维胶原纤维和平滑肌。用计算机图像分析系统测量脐带静脉的几何形态及显微结构成分的含量。结果：从近段到远段，脐带静脉中膜厚度及外径值逐渐减小。胶原纤维的相对含量近段比远段少，由近段到远段C／E值逐渐增大。结论：脐带静脉可作为小口径动脉移植的替代材料。但移植时，应注意选择不同段脐带静脉，使之与宿主血管匹配。     

不同段脐带静脉的生物力学特性及其临床应用价值

目的 :为脐带静脉作为小口径移植材料的临床应用提供理论依据。方法 :采用胎龄在 3 7～ 40周自然分娩正常胎儿脐带静脉 2 0例 ,在生物软组织力学试验机上测定不同段脐带静脉的压力 -直径关系 ,计算出弹性模量。横断取材 ,冰冻切片 ,HE法染色 ,用计算机图像分析系统测量其几何形态学指标。结果 :近、中、远段脐带静脉的Einc、Ep和Ev均随压力的上升而增大 ,近段 3种弹性模量均低于远段 (P <0 .0 1) ,由近段到远段呈增大趋势。中膜厚度及外径值从近段到远段逐渐减小。结论 :脐带静脉作为小口径动脉移植的替代材料是可行的 ,在血管移植时 ,应注意选择不同段脐带静脉 ,使作为移植材料的脐带静脉与宿主血管材料间的生物力学特性尽量相近 ,以提高移植血管的远期通畅率     

胎儿脐静脉壁组织结构增龄性变化的定量分析

目的 :探讨胎儿脐带静脉随胎龄变化的形态学改变 ,为临床挑选适当的血管代用品提供科学的理论依据。方法 :3 3例新鲜脐带 ,常规石蜡包埋、切片、HE染组织结构 ,Weigert,AnilineBlue及桔黄G分染弹性纤维 ,胶原纤维和平滑肌 ,光镜观察及计算机图像分析。结果 :随胎龄随长 ,脐静脉管径、中膜厚度、中膜弹性纤维含量逐渐增多 ;平滑肌含量及细胞核的数密度和面密度在 3 7～ 40周最大 (P <0 .0 5 ) ,胶原纤维则最小 ,因而此时段顺应性最好。结论 :脐静脉管壁中各成分的含量随胎龄变化呈不等比增长 ,3 7～ 40周时血管顺应性最好。建议选用此时段胎龄的脐静脉作为移植材料。     

胎儿静脉壁组织结构增龄性变化的定量分析

目的：探讨胎儿脐带静脉随胎龄变化的形态学改变，为临床挑选适当的血管代用品提供科学的理论依据。方法：33例新鲜脐带，常规石蜡包埋、切片、HE染组织结构，Weigert,Aniline Blue及桔黄G分染弹性纤维，胶原纤维和平滑肌，光镜观察及计算机图像分析。结果：随胎龄随长，脐静脉管径、中膜厚度、中膜弹性纤维含量逐渐增多；平滑肌含量及细胞核的数密度和面密度在37－40周最大（P＜0．05），胶原纤维则最小，因而此时段顺应性最好。结论：脐静脉管壁中各成分的含量随胎龄变化呈不等比增长，37－40周时血管顺应性最好。建议选用此时段胎龄的脐静脉作为移植材料。     

自体静脉移植血管结构成份的变化

选用16只健康杂种犬,将股静脉移植于股动脉,术后分别观察4,12,24周,采用图像分析方法,测定各时间组移植血管弹性纤维和胶原纤维的相对含量.结果发现:自体静脉移植术4周后相当长一段时间管壁弹性纤维相对含量无明显差别,与正常静脉相同(P>0.05),低于正常动脉(P<0.01);移植血管、正常静脉和正常动脉管壁胶原纤维相对含量无明显差别(P>0.05);移植血管刚度值(C/E)与正常静脉相同(P>0.05),低于正常动脉(P>0.01);表明移植血管具有与正常静脉相同的弹性特性.     

不同胎龄脐带静脉顺应性的变化及其临床意义

目的：为脐带静脉的临床应用从生物力学性质上提供理论依据。方法：采用胎龄以24－42周流产及自然分娩正常胎儿脐带静脉50例，测定其压力－容积关系。结果：脐带静脉的p-V曲线可用抛物线拟合。脐带静脉顺应性随胎龄增加而增大，但39周以后又降低。结论：人脐带静脉是动脉移植物的良好替代材料，在移植时除了考虑脐带静脉与宿主动脉相匹配外，还应注意其顺应性与胎龄的关系，建议选用胎龄在37－40周之间的脐带静脉作为临床应用的移植材料。     

胎儿脐带静脉的蠕变特性

为脐带静脉作为小口径移植材料的临床应用提供蠕变特性指标。对产妇年龄在22～28岁,胎龄37～40周自然分娩正常胎儿脐带静脉近胎盘段和远胎盘段各10个试样在日本岛津电子万能试验机上进行蠕变实验,模拟人体温在36.5±0.5℃的温度场下以0.01 Mpa/s的应力增加速度对试样施加应力,设定时间为7 200 s。采集100个数据,采用归一化分析的方法计算两组试样的归一化蠕变方程。两组试样蠕变曲线是以指数关系变化的,胎儿脐带静脉近胎盘段和远胎盘段7 200 s蠕变量差异显著(P<0.05)。胎儿脐带静脉近胎盘段和远胎盘段具有不同的蠕变特性。     

胎儿脐带静脉的生物力学特性研究

探讨胎儿脐带静脉随胎龄变化的生物力学特性的改变,为临床挑选适当的血管代用品提供理论依据。方法：33例新鲜脐带静脉,用生物软组织力学试验机测定血管的压力、容积、外径等力学参数,计算出弹性模量、顺应性。结果：37－40周时脐静脉的P－V曲线比较高,弹性模量与血压的关系曲线较低,此时段顺应性最好。结论：建议选用胎龄在37－40 周之间的脐静脉作为移植材料。     

门静脉高压症猪肺血管的结构重建及临床意义

目的:探讨门静脉高压症猪肺血管形态结构重建的特点。方法:采用健康2月龄湖北白猪14头,随机分为正常对照组和实验组,用四氯化碳建立门静脉高压症模型。取肺动脉和肺静脉,横断切片。用Pilloridine和Cy3-IgG分别染胶原纤维和平滑肌,弹性纤维自发荧光。在激光共聚焦显微镜下观察,用计算机图像分析系统测量各结构成分的相对含量。结果:与正常对照组相比,门静脉高压猪肺血管壁中胶原纤维、平滑肌的相对含量及胶原纤维与弹性纤维的比值(C/E)均增大,弹性纤维则减少。结论:门静脉高压时,猪肺血管的形态结构可发生重建,表现为胶原纤维增加,弹性纤维减少,导致C/E值的改变。肝肺联合移植时,移植材料间的结构成分的差异也应引起关注。     

自体静脉移植血管的应力应变关系及其相关组织形态学研究

本文研究了自体移植静脉的应力应变关系 ,将狗股静脉移植于股动脉 ,术后 6个月切取移植静脉进行轴向及环向的单轴拉伸实验及组织形态学观测 ,并和正常股静脉、股动脉的应力 应变关系及组织形态学进行了比较。结果表明 ,轴向移植静脉及正常静脉、动脉的应力 应变关系可表示为 :T =C1 (eα1(λ-1 ) - 1) (T <10kPa)和T =C2 eα2 (λ-1 ) - β(T≥ 10kPa) ,环向应力 应变关系可表示为 :T =C3(eα3(λ-1 ) - 1)。移植术后的静脉与正常静脉、动脉相比 ,轴向和环向静脉的应力 应变曲线均向左移 ,移植术后血管管壁组织结构的刚度比正常静脉、动脉的大 ;比如 ,移植静脉和正常静脉、动脉轴向的α2 (mean±SD)的值分别为 :34 .0 6± 7.30、19.2 1± 2 .35和 11.68± 0 .2 636,环向的α3(mean±SD)的值分别为 :55.76± 2 0 .16、2 7.56± 2 .82和 2 3 .0 8± 1.2 74 1,这显示了移植血管管壁组织在术后硬化的特性。组织形态学的研究表明 ,移植术后血管的管壁材料组份及结构发生了变化 ,管壁弹性纤维含量与正常静脉相比无显著差异 ,但远低于正常动脉 ;例如 ,弹性纤维在正常动脉、静脉及移植血管中的含量分别为 (mean±SD) :4 8.9± 4 .3、19.6± 0 .6和 19.9± 2 .7,说明移植血管并未出现动脉化趋势。此外 ,移植术     

Biomechanical properties of different segments of human umbilical cord vein and its value for clinical application

No satisfactory effects have been obtained with the use of synthetic blood vessels (diameter <6 mm) as substitutes for human small arteries or veins for the purpose of clinical vascular reconstruction. Therefore, blood vessels of human origin, for example, umbilical cord blood vessels, with their wide availability, still should be considered. However, little information on biomechanical properties of human umbilical cord blood vessels is available. The objective was to provide a theoretical basis for the clinical application of umbilical cord veins as optional material for small-caliber grafts. This was a nonrandomized, noncontrolled in vitro study. The experiment was conducted in the Laboratory of Medical Biomechanics, Yunyang Medical College. Umbilical cord veins of 20 normal fetuses of spontaneous labor were collected by the Department of Obstetrics and Gynecology, Taihe Hospital in Shiyan City, Hubei Province. The fetuses aged 37-40 weeks, and the parturients were 20-30 years old. Umbilical cord veins of the 20 fetuses were used and the placental ends were treated as proximal ends while the fetal ends as distal ends. The fetal ends were divided into three segments: proximal, middle, and distal segments. The relationship between pressure of umbilical cord veins segments and the diameters was measured on the biomechanical experiment stand for soft tissues, and then the elastic modulus was calculated. The materials were transversely extracted, refrigerated, and sliced up before HE staining. The geometrical morphology indexes were measured by a computer image analysis system (Leica-Q500IW). The main outcome measures were: incremental elastic modulus (E(inc)), pressure-strain elastic modulus (E(p)), volume elastic modulus (E(v)), diameter, and wall thickness of the veins. E(inc), E(p), and E(v) of umbilical cord veins of proximal, middle, and distal segments increased with the pressure elevated. The three kinds of elastic modulus of proximal segments (E(inc): 26.98 +/- 3.21, E(p): 16.58 +/- 2.12, E(v): 8.31 +/- 2.35) were all lower than those of distal segments (E(inc): 33.20 +/- 4.21, E(p): 119.45 +/- 2.87, E(v): 9.71 +/- 1.32) (F = 95.74-126.52, p < 0.05), and a tendency to increase was shown from proximal segments to distal segments. Media thickness [(0.30 +/- 0.05)] mm, (0.24 +/- 0.03) mm] and the diameters [(3.07 +/- 0.12) mm, (2.30 +/- 0.13) mm] decreased gradually from proximal to distal segments (F = 12.76, p < 0.01). It is feasible to use umbilical cord veins as substitutes for the transplantation of small-caliber arteries in terms of basic biomechanical properties. On vascular grafting, different segments of umbilical cord veins should be chosen cautiously so that the biomechanical characteristics of umbilical cord vein grafts could be in accordance with those of host to increase the long-term patency rate of transplanted blood vessels.     

Pre-eclampsia associated alterations of the elastic fibre system in umbilical cord vessels

Although pre-eclampsia (PE) is often associated with fetal hypoxia, hypertension and/or disturbed function of the fetal circulation, the effect of these altered hemodynamic parameters on the structure and composition of umbilical vessels has not been systematically investigated before. Therefore, this study focuses on PE-associated changes of the elastic fibre system in umbilical cord vessels investigated by light and electron microscopy, immunocytochemistry and biochemistry. In umbilical cord veins, no changes in thickness of the vessel wall or of any sublayer were observed. However, the internal elastic lamina of the veins was split in 80% of the PE-group in contrast to 20% in uncomplicated pregnancies. This effect was significant (α <0.01) from 36 weeks of gestation onwards. In umbilical cord arteries, the entire arterial vessel wall was found to be 15% thicker in PE than in uncomplicated pregnancies. The enlargement was caused by an increase of both the tunica intima and tunica media. The thickening of the tunica intima was attributed to a migration of smooth muscle cells towards the endothelium, accompanied by a splitting of the internal elastic lamina. Compared to uncomplicated pregnancies, smooth muscle cells of arteries and veins in PE showed a metabolic activation demonstrated by highly dilated endoplasmic reticulum. A semiquantitative score method as well as a quantitative dot blot assay indicated a PE-associated reduction of elastin expression in the arterial vessel walls. In summary, PE obviously induces a decrease of the elastin content accompanied by a thickening of the vessel wall in umbilical cord arteries. This remodeling of the elastic fibre system, together with an increased migration of smooth muscle cells, might represent part of the functional adaptation system of the umbilical cord arteries on the altered hemodynamic conditions in PE. Accepted: 29 November 1999     

不同胎龄人脐血管的生物力学特性及其临床意义

为人脐血管的临床应用从生物力学性质上提供理论依据。采用胎龄在24－42周流产及自然分娩正常胎儿脐动脉和脐静脉50例,测定其压力－容积关系,并求出其顺应性。发现脐动脉和脐静脉的P－V曲线可用抛物线来拟合。获得了脐动脉和脐静脉顺应性随胎龄增加而增大,但39周以后又降低的变化规律。脐静脉顺应性是脐动脉的2－3倍。人脐动脉和脐静脉是动脉移植物的良好替代材料,在移植时除了考虑脐血管与宿主动脉顺应性相匹配外,还应注意其顺应性与胎龄的关系,建议选用胎龄在37－40周之间的脐动脉和脐静脉作为移植材料。     

不同孕周人脐带间充质干细胞移植改善心肌梗死模型心脏功能的比较

BACKGROUND: Stem cells have multi-directional differentiation and self-replication abilities, under certain conditions, which can differentiate into myocardial cells to repair the damaged myocardium. OBJECTIVE: To investigate the effects of transplantation of umbilical cord mesenchymal stem cells derived at different gestational weeks on infarct size and angiogenesis in the infarct region of experimental rabbits with myocardial infarction. METHODS: Ten full-term umbilical cord samples and 10 umbilical cord samples of aborted fetuses at 10-12 gestation weeks were selected to in vitro isolate umbilical cord mesenchymal stem cells that were subjected to BrdU labeling. HLA-G expression was detected in the cells. Thirty white rabbits were selected to make myocardial infarction models, and 2 weeks after modeling, the model rabbits were randomized into aborted cell transplantation group, full-term cell transplantation group and control group (n=10 per group). Then, BrdU-labeled cells were injected correspondingly into the infarct region of rabbits in the two cell transplantation groups. Rabbits in the control group were subjected to an equal volume of serum-free. Four weeks after transplantation, heart function of rabbits was monitored using electrocardiogram, and myocardial tissues were taken to measure infarct size and blood capillary density. RESULTS AND CONCLUSION: HLA-G expression was different in different sources of umbilical cord mesenchymal stem cells: high HLA-G expression was found in the aborted umbilical cord mesenchymal stem cells, and meanwhile, low HLA-G expression was found in the full-term umbilical cord mesenchymal stem cells. Compared with the control group, the left ventricular end-diastolic volume and left ventricular ejection fraction of aborted and full-term cell transplantation groups were significantly improved, especially in the aborted cell transplantation group (P < 0.05). BrdU-positive cells were found in the infarct site in both transplantation groups. Compared with the control group, the infarct size and capillary density were improved most significantly in the aborted cell transplantation group followed by the full-term cell transplantation group (P < 0.05). Electrocardiogram findings showed significant improvement in both cell transplantation groups compared with the control group (P < 0.05), especially in the aborted cell transplantation group. These findings indicate that umbilical cord mesenchymal stem cells derived at low gestational weeks improve the heart function more significantly than the full-term umbilical cord mesenchymal stem cells, which have the potential to become a better source of cardiomyocytes for transplantation.     

Restricted innervation of uterus and placenta during pregnancy: evidence for a role of the repelling signal Semaphorin 3A.

Because data from the literature suggest a lack of innervation of the placenta, we have investigated placenta, umbilical cord, and uterus to identify the molecules that play a role in regulating innervation in these organs. Neuropilin-1 and Plexin-A1 are cell surface proteins that form a receptor complex for Semaphorin 3A (Sema 3A), a secreted molecule mediating repelling signals for axonal growth cones. We have analyzed the expression of Neuropilin-1, Plexin-A1, and Semaphorin 3A in the above-mentioned tissues on the hypothesis that these molecules could regulate innervation in these organs during gestation. We found that nervous fibers are only present in the proximal part of the umbilical cord, close to the newborn, and in nongestational uterine tissues. In contrast, nervous fibers are not present in the distal segment of the umbilical cord, in the placenta and in the uterine tissues during gestation. We also found that Sema 3A receptors, Neuropilin-1 and Plexin-A1, are expressed by the nervous fibers of the proximal part of the umbilical cord, whereas Sema 3A is secreted in the umbilical cord, in the placenta, and in gestational uterine tissues. We report that a factor secreted in the umbilical cord induces the collapse of neurite growth cones in vitro and provide evidence that this factor is Sema 3A. In summary, our results suggest that the chemorepulsive signals mediated by Sema 3A play an important role in preventing nerve fibers growth in the umbilical cord and in gestational uterine tissues. The inhibition of nerve growth into the myometrium as well as into the placenta could be considered fundamental processes to preserve the fetus from external stressful events.     

Human vascular smooth muscle in culture. Growth and ultrastructure.

Mixed primary cultures of endothelial and smooth muscle cells were obtained from human umbilical cord vessels after prolonged collagenase digestion of their luminal surfaces. Morphologically homogeneous populations of vascular smooth muscle were then selectively isolated and subcultured for up to 16 weeks. Ultrastructurally, cultured cells were characterized by the presence of bundles of myofilaments with dense bodies similar to native umbilical vessel smooth muscle. Mature cultures developed a distinctive topographical organization consisting of bands of parallel cells and intertwined, multilayered areas. Elaborate intercellular attachments formed along contiguous cell surfaces. Large amounts of extracellular material accumulated, including amorphous substance, elastic fiber microfibrils, and 250- to 300-A,faintly-banded fibrils. In older cultures, focal proliferation, extracellular material secretion and cellular degeneration produced nodular protrusions somewhat resembling atherosclerotic lesions in vivo. Endothelium and smooth muscle cultured from this readily available human source may provide useful comparative material for pathophysiologic studies of vascular disease.