15 人脑海马内部微血管三维构筑的研究

<正>本文采用5例有机玻璃单体铸型标本,暗视野全景观察和日立S—450扫描电镜观察,较完整地显示人脑海马内部血管从动脉—微动脉—毛细血管前括约肌—毛细血管—微静脉—小静脉连续性立体构筑。海马内微动脉与微静脉有着特殊的分布形式,本文观察到一支动脉分细支或数条动脉的分支组成血管网,数支微动脉伴随一条微静脉为-血管单位,毛细血管互相交织成不规则的血管网.皮质动脉分支走向及毛细血管袢长轴与神经纤维走向平行。皮质长、短动脉各序支管随年龄增长而变粗;皮质动脉在深部发支返回浅层。本文观察到微血管间存在多种吻合:1.微动脉间吻合;2.毛细血管前动脉间吻合;3.微动脉与微静脉间吻合;4.微静脉间有搭桥式吻合。微血管形态特征;小动脉壁有卵圆形的内皮细胞核压迹,排列整齐,清晰可见。小静脉壁有圆形的内皮细胞核压迹。较大数量的毛细血管前括约肌和微动脉末端肌纤维包绕管壁形成纹理的微动脉括约肌,微动脉管径突然变细呈锥状与毛细血管相连接。毛细血管汇入静脉,静脉属支呈“树根状”。     

猴甲状腺微血管构筑的扫描电镜观察

本文在扫描电镜下观察了猴甲状腺微血管的构筑。甲状腺的血管自小叶间动脉、滤泡间小动脉、滤泡间微动脉,最后由入球微动脉在滤泡周围分支形成篮网状滤泡毛细血管网。该网自动脉极向静脉极过渡形成三级毛细血管,即由入球微动脉首先分出分支毛细血管网,延续为网状毛细血管网和集合毛细血管网,最后在滤泡的静脉极汇集成出球微静脉。猴甲状腺滤泡毛细血管网大小不同,且独立存在。     

婴儿和足月胎儿下颌下腺的微血管构筑

用血管铸型扫描电镜法，观察了婴儿和足月胎儿下颌下腺的微血管构筑，腺泡微动脉自小叶内部行至腺泡周围分成毛细胞管网，或穿出小叶至小叶的基底面，沿小叶表面延伸并分成毛细血管网，腺泡毛细血管网排列稀疏。足月胎儿的纹状管周围为毛细血管后微静脉和微静脉交织吻合成的网状微静脉丛。婴儿的纹状管周围为排列密集的毛细血管网。足月胎儿的腺泡毛细血管汇入纹状管周围微静脉丛，婴儿的与纹状管周围毛细血管网相连。小叶间导管周围     

人腮腺微血管构筑

用血管铸型扫描电镜法，观察人腮腺微血管的构筑。从铸型上看，腮腺各小叶的界限分明。小叶的表层为管径粗细一致的毛细血管，它们在腺泡和闰管周围相互吻合成毛细血管网。腺泡和闰管周围毛细血管网起自腺泡微动脉。腺泡微动脉主要起自小叶内动脉，但也可起自小叶间动脉。纹状管周围为毛细血管后微静脉和微静脉相互吻合形成的网状静脉丛。小叶间导管起始部的周围，为一层由毛细血管和毛细血管后微静共同形成的微血管网，随着小叶间导     

扫描电镜对胎儿左心室壁内微血管构筑的观察

用血管铸型结合扫描电镜方法研究了5例胎儿左心室壁内微血管构筑。在心肌中层内,较大的微动、静脉伴行,呈“层状”分布。微动脉与微静脉的关系是:微动脉两次近似直角双叶状分支,毛细血管汇集成毛细血管后微静脉或直接以直角汇入微静脉。在心外膜下层,微动脉间吻合丰富,分出毛细血管有两种形式。在心内膜下层,微动、静脉不伴行,微静脉数目多见,而微动脉较少。毛细血管间吻合复杂。本文对不同心肌层内的毛细血管口径、间距进行了测量,并讨论了胎儿左心室壁内微血管构筑特征和微循环模式。     

用注射复型SEM方法研究足月胎儿小肠粘膜的微循环

本文用注射甲基丙烯酸甲酯复型扫描电镜方法,研究了足月胎儿小肠粘膜血管的立体构筑形象。绒毛毛细血管网的特征为管腔大部分呈窦状,其间夹杂有直形毛细血管;在十二指肠乳头处,胆总管壶腹口周围及壶腹粘膜的毛细血管多呈丛状,未见窦状毛细血管。绒毛的毛细血管网接受来自三方面的动脉血,即通过来自粘膜下动脉的微动脉,从绒毛顶部、基底部和腺丛的交通支,向绒毛毛细血管网供血。后者构成小肠绒毛的“门脉系统”。微动脉在绒毛顶部与微静脉有交通支,构成动静脉吻合。微静脉从顶部到基底部贯穿整个绒毛,沿途自绒毛毛细血管网及腺丛接受属支,最终注入粘膜下静脉,与Mall的典型的“喷泉型”概念并不完全一致。     

葡萄膜血管铸型的扫描电镜观察

本文用死后2～4小时的5具新生儿尸体,以 ABS 丁酮溶液经颈总动脉灌注后,剥下葡萄膜,在40%KOH 液中腐蚀4～5天,把所得到的血管腐蚀铸型,在扫描电镜下进行观察。可见脉络膜的血管由大血管层,小血管层和毛细血管层组成。脉络膜的毛细血管层是由许多脉络膜毛细血管小叶组成的。小叶的中央是毛细血管前小动脉,毛细血管呈放射状离开小动脉,与邻近小叶互相吻合,形成连续单层的互相吻合的毛细血管网。毛细血管小叶由斜行或垂直于毛细血管层的毛细血管后小静脉引流。脉络膜毛细血管小叶呈多边形的几何图形。脉络膜的毛细血管突然终止于视神经乳头周围,不参与视神经乳头的血液供应。睫状体和虹膜的血管来自虹膜动脉大环,每个睫状突由一条小动脉供应,形成睫状突的毛细血管丛,它由小静脉引流。睫状突主要由血管构成。     

应用单宁酸-氯化铁法显示小脑不同部位的微血管构筑

目的　光镜下观察 6只大鼠小脑前叶、后叶及蚓部微血管构筑。方法　用单宁酸 -氯化铁法 (TAFM)媒染显示小脑内血管。结果　小脑各部位皮质、髓质动脉均来源于软脑膜动脉和小脑动脉中央支 ,软脑膜动脉分支多以直角进入小脑皮质 ,分别在分子层、蒲肯野细胞层、颗粒层形成毛细血管网 ;小脑后叶髓质中微动脉呈爪状分支 ,小叶两侧皮质深层微动脉或毛细血管可跨过髓质互相沟通。结论　 TAFM显示小脑微血管构筑清晰、立体感强 ,并发现小叶内皮质深层微血管之间有吻合支     

大鼠睾丸血管构筑的观察

本文通过血管灌注透明标本和微血管腐蚀铸型扫描电镜,观察大鼠睾丸的大血管和微细血管的构筑。大鼠生精小管的周围,有两种小血管配布。1.管间血管:该血管或为1条毛细血管前微动脉,或为2条并行的较大的毛细血管连结成网状,位于生精小管间三角形的间质柱内,并与小管平行走行。2.管周毛细血管:连于管间血管之间,呈绳梯状围绕生精小管,并在生精小管上皮下固有膜内,形成管周毛细血管网。本文还观察了大鼠睾丸较大血管及睾丸固有鞘膜脏层的血管配布特点,讨论了这些血管配布的意义。     

人窦房结和房室结微血管的扫描电镜观察

本文用4例新鲜婴儿尸体,采用血管铸型扫描电镜法,观察人窦房结、房室结微血管的立体构筑。结果表明,窦房结的血管床是由微血管网构筑成一椭圆形网状结构,中央动脉贯穿于结的长轴,由此动脉向周围发出分支,逐级分为许多微动脉和毛细血管前微动脉,最后在结的浅部分成毛细血管网。毛细血管后微静脉的收集范围,则显示出按区收集的特点。而房室结微血管构型是一扁圆形的微血管网,结的浅部为一薄层比较细密的毛细血管网。透过网眼,可见有粗大的、彼此吻合的窦状静脉丛。房室结动脉由结一侧进入结内,向周围逐级分支,形成毛细血管前微动脉,穿行于静脉丛之间,在结的浅部连于毛细血管网。毛细血管后微静脉的始端有环形缩窄,为平滑肌压痕。     

Development of the retinal circulation in the pig

Retinal angiogenesis was studied in 300 eyes of 150 porcine fetuses by means of semithin histologie sections and vascular corrosion casts. In the embryonic and early fetal period, the retina is avascular and nourished via diffusion from the choriocapillaris and the vascular tunic of the lens. The development of the inner vascular plexus of the retina occurs in three different stages. In the first stage (angioblast phase), during gestational weeks 6–7, mesenchymal precursor cells arising from the arterial and venous circle around the optic nerve invade the nerve fiber layer of the retina via the optic disc border. They form a network of angioblasts that gives rise to an immature capillary network in the second stage (angiogenesis phase). This vascular monolayer is located within the nerve fiber layer and reaches the ora serrata around gestational weeks 9–10. Initially, the immature retinal capillaries have an irregular appearance with wide lumina and relatively small intercapillary meshes. Subsequently, the lumina become smaller by involution and atrophy. In the third stage (maturation and remodeling phase) the immature blood vessels differentiate into retinal arterioles, capillaries and venules. From gestational week 11 onwards, the larger retinal arterioles are surrounded by a distinct periarteriolar capillary-free zone. The three stages start at the optic disc and extend centrifugally towards the retinal periphery. The development of the outer vascular plexus is essentially different from the angiogenesis of the inner vascular plexus. The outer retinal vessels that are located in the inner nuclear layer arise from previously developed capillaries and venules located in the inner vascular plexus. Moreover, the development of the outer vascular plexus starts at the macula and proceeds along with the maturation of the neural retina.     

Astrocyte invasion and vasculogenesis in the developing ferret retina

We studied the time course of astrocyte invasion and blood vessel formation in the developing ferret retina using glial fibrillary acidic protein (GFAP)-immunohistochemistry for astrocytes and isolectin B4 histochemistry for blood vessels. As in other mammals, strongly GFAP positive astrocytes invade the ferret retina from the optic nerve. At birth, strongly GFAP positive astrocytes have reached about 22% of the distance between optic disc and outer retinal edge whereas weakly GFAP positive processes already extend to the edge of the retina. At postnatal days P30–P37 about 82% of the distance between optic disc and outer retinal edge and in the adult 88% of this distance is covered with strongly labelled astrocytes. Superficial blood vessels form from the optic disc. They reach up to about 24% of the retinal radius at birth and grow radially across the retina during further development. At P30–P37, the whole retina is covered with superficial blood vessels. The deep vascular layer forms later (around P30) through sprouting from superficial vessels. The radial pattern of astrocyte and vessel growth from the optic disc is not affected by the formation of the area centralis and visual streak.     

Retinal blood vessels are damaged in a rat model of NMDA-induced retinal degeneration

Retinal ischemia–reperfusion causes capillary degeneration but the mechanisms of damage are not well understood. The NMDA receptor plays an important role in neuronal damage after ischemia–reperfusion. Therefore, we determined whether retinal blood vessels are damaged structurally and functionally in a rat model of retinal degeneration induced by NMDA. At 7 days after a single intravitreal injection of NMDA (200 nmol) into the eye, loss of retinal ganglion cells and thinning of the inner plexiform layer were observed. Endothelial cells disappeared in some regressing vessels and empty basement membrane sleeves were left as remnants of the vessels. The number of basement membrane sleeves was increased in the NMDA-treated retina and non-perfused vessels were found in the injured retina. These results indicate that retinal blood vessels are damaged in the NMDA-induced retinal degeneration model. Neuronal cells may play a role in maintaining normal structure and function of the vasculature in the retina.     

BP神经网络在眼底造影图像分割中的应用

背景:通过眼底荧光血管造影(FFA)所得到的数字图像以及对其进行处理所得到的数据,可反映视网膜血管结构、血流动力学改变、血管病理生理变化及其相关结构的病理改变,广泛应用于视网膜、脉络膜及视神经疾病的鉴别诊断。目的:通过分析眼底造影图像和BP神经网络的特点,利用BP神经网络对眼底造影图像进行分割,并将其利用到眼科的临床辅助诊断之中。方法:将待分割图像区域分为背景和目标两类,用手工方法得到这两类的样本图像,提取样本图像的特征,如灰度、方差、纹理等;对提取的样本特征值进行归一化处理,输入神经网络分类器,利用BP训练算法进行训练;输入待分类的医学图像,提取图像特征,并进行归一化处理;将归一化后的特征值,输入已训练的神经网络分类器进行分类,得到眼底造影图像的分割结果。结果与结论:本文使用的眼底造影图像分割方法抗干扰能力强,分割的眼底造影图像清晰、内容丰富。可以为眼科医生的临床诊断提供较大帮助。     

Oxygen modifies artery differentiation and network morphogenesis in the retinal vasculature.

The mechanisms that control differentiation of immature blood vessels into either arteries or veins are not well understood. Because oxygen tension in arteries is higher than in veins, oxygen has the potential to be an instructive signal for artery/vein (AV) differentiation. We test this hypothesis by exposing newborn mice to moderate hypoxia (10% atmospheric oxygen) and studying AV differentiation in the developing retinal vasculature. Forming retinal arteries fail to express the artery-specific markers Delta-like 4 (Dll4) and EphrinB2 during hypoxia. However, other aspects of AV differentiation are retained such as high levels of alpha smooth muscle actin in arterial mural cells and vein-specific expression of the msr/apj gene. The capillary network between arteries and veins is denser, and capillaries expressing the venous marker msr/apj are found in territories normally occupied by arterial capillaries. Thus, it appears that high oxygen in arterial blood is required for arterial expression of Dll4 and EphrinB2, which could be involved in cell-cell repulsion pathways that dictate the normal segregation of arteries and veins.     

明胶墨汁与荧光微球显示大鼠视网膜微血管灌流效果的对比研究

目的:比较明胶墨汁灌注与荧光微球灌注对大鼠视网膜微血管灌流情况的显示效果。方法:12只成年健康SD大鼠随机分成荧光微球组(6只)和明胶墨汁组(6只)。明胶墨汁组分两步经左心室灌注明胶墨汁40ml。荧光微球组经股静脉注射荧光微球0.5ml。视网膜行铺片和切片,观察荧光微球和改良墨汁灌注显示的微血管灌流情况;两组视网膜切片还进行NeuN、Parvalbumin和GFAP的免疫组化染色。结果:荧光微球零散分布于视网膜铺片周边部和中央部视的网膜血管中;不能显示铺片的血管轮廓和切片中的血管截面。荧光微球与NeuN、Parvalbumin或GFAP免疫组化双标不能在同一组织中准确显示视网膜血管与神经细胞的紧密空间关系。改良墨汁灌注能清晰显示大鼠视网膜铺片中周边部和中央部的血管网,以及切片中的血管截面,而且此方法与NeuN、Parvalbumin或GFAP免疫组化双标能在同一组织中准确显示视网膜血管与神经细胞的紧密空间关系。结论:改良明胶墨汁灌注在显示大鼠视网膜微血管灌流情况方面优于荧光微球,适宜于在视网膜疾病研究中广泛使用。     

The arteries of the humeral head and their relevance in fracture treatment

Bone vascularisation has gained increased interest in relation to the blood supply of bone fragments during treatment of fractures. In the current study the pattern of vascular supply of the proximal humerus was studied in six cadavers by the corrosion technique. Furthermore, the effect of fractures on the vascular supply was also investigated. In all preparations the intraosseous arteries of the humeral head arose from the circumflex arteries, which surrounded the humerus and dispatched branches towards the proximal end. The main vessel was the branch of the anterior circumflex artery, penetrating the major tubercle in six of six cases. Due to the intraosseous arch shape of this vessel it is referred to as the arcuate artery. Besides other smaller vessels, there was also a vascular network arising from the posterior circumflex artery. Their branches penetrated medially at the cartilage bone interface in five of six preparations. The medial bone arteries appear to gain distinctive importance in humeral head fractures by their impact on the vascularisation of the fracture fragments. After disruption of the arterial supply from the arcuate artery, the vascularisation of the head fragments is most likely ensured by this group of vessels. Therefore, necessary repositioning manoeuvres during open reduction of the fracture should be conducted with care in order to preserve these arteries.     

Vimentin intermediate filament protein as differentiation marker of optic vesicle epithelium in the chick embryo

For the study of the differentiation process of optic vesicle epithelium into neural retina, pigment epithelium and pars caeca retinae, vimentin intermediate filament protein in retinal epithelial cells was detected immunohistochemically in chick embryo at stages 11-21. In the late stage of optic vesicle development (stage 14), optic vesicle epithelium was classified into the following 3 different portions on the basis of vimentin staining intensity: latero-central epithelium under the lens placode, medio-central epithelium facing the latero-central epithelium, and peripheral epithelium connecting the latero-central and medio-central epithelia. Latero-central epithelium, the future neural retina, exhibited strongest staining of vimentin of the 3 portions. In contrast, medio-central epithelium, the future pigment epithelium, showed weakest staining. Moderate staining was observed in peripheral epithelium, the future pars caeca retinae. These differences in levels of vimentin expression were observed during optic cup formation. The present results clearly demonstrate that differentiation of retinal epithelium into neural retina, pigment epithelium and pars caeca retinae occurs in the late stage of the optic vesicle, and that retinal differentiation is reflected by the amount of vimentin in epithelial cells.     

Studies on ocular blood flow and retinal capillary permeability to sodium in pigs

A surgical technique was developed in pigs that permits access to the retinal venous plexus surrounding the optic nerve. The effect of surgery on ocular blood flow and capillary permeability was evaluated. Blood flow, determined by the labelled microsphere technique, did not differ significantly between operated and control eyes. Increased intraocular pressure in the operated eye reduced blood flow through the choroid and the anterior uvea in proportion to the reduction in perfusion pressure, while in the retina a smaller reduction in blood flow occurred indicating that autoregulatory mechanisms are involved in the control of retinal blood flow. The capillary permeability to sodium was studied by the single injection technique, using albumin as a reference substance. The fractional initial extractions from the choroidal and the retinal vessels were 0.77 and -0.001 respectively. The absence of a sodium extraction from the retinal vessel indicates that this part of the blood-retinal barrier was intact and that the blood drained by the retinal plexus is not mixed with blood from other sources.     

The active transport of fluorescein by the retinal vessels and the retina

1. The movement of fluorescein across the retinal surface of the rabbit's eye was estimated by measuring the concentration gradient of the dye in the vitreous body. These measurements were made in vivo by means of a slit-lamp fluorophotometer, or were taken from frozen sections of enucleated eyes.2. In the normal eye, fluorescein does not pass from the blood to the vitreous body across any part of the retina. When injected into the vitreous body it passes rapidly out across the entire retinal surface, even against a very large concentration gradient.3. A variety of metabolic and competitive inhibitors, effective in blocking organic anion transport in the kidney and liver, tend to abolish this unidirectional movement of fluorescein across the retina.4. The region occupied by the retinal vessels is more sensitive to inhibition than other areas of the retina. Occlusion of the vessels by diathermy prevents the exchange of fluorescein in this region.5. It appears, then, that there is an active transport of organic anions out of the vitreous body, both by the retinal capillaries and by the retina itself. The latter system is probably located in the pigment epithelium and seems to be carried forward to the rear surface of the iris.6. Since the walls of the retinal vessels of the rabbit are freely in contact with the vitreous body, the active transport must take place across the capillary endothelial cells themselves. These vessels have structural and permeability characteristics found only in the central nervous system and it is to be presumed that the anion transport system is shared by the capillaries of the brain.7. The function of the transport in the retina may be to protect the nervous tissue from toxic materials by preventing their entry from the blood or by removing products of metabolism conjugated as organic anions. Alternatively, the mechanism may be concerned in maintaining the normal adhesion of the retina to the choroid, since retinal detachment was observed to follow its total inhibition.