冠状动脉旁路移植术桡动脉桥家兔模型的建立

目的建立一个能模拟冠状动脉旁路移植术桡动脉桥情况的模型。方法50只新西兰兔,股动脉与颈总动脉行端侧吻合,两吻合口之间的颈总动脉予以结扎。术后1、3、7、14、56d分别取完整动脉桥,进行肉眼观察,HE染色观察病理变化,弹力纤维染色,计算机测算血管内膜厚度、新生内膜中膜比指数;电镜观察血管内皮细胞变化。结果50只兔成功建立动脉桥,无手术及围手术期死亡,桥血管总通畅率为86％,对通畅的桥血管作形态学观测发现血管移植后7d起至56d内膜增厚有统计学差异。结论本动物模型可以较好地模拟冠状动脉旁路移植术桡动脉桥的情况。     

A scanning electron microscope study of human cerebral arteries.

Human cerebral arteries were obtained from autopsy, fixed under pressure, cut open, and tacked onto pieces of cork. For one artery the intima was partly teased away, exposing the media, and treated with a silver nitrate process. For another artery the adventitia was exposed. Both arteries were processed through graded ethanols and coated with gold paladium for the scanning electron microscope. The collagen fibers of the adventitia were approximately 5 mum in diameter and consisted of a bundle of microfilaments, each of which had a diameter of 800-1000 A (1 A = 10(-10) m). The collagen fibers were oriented parallel to the long axis of the artery. The muscle cells of the media had a diameter of 2-5 mum and were arranged circumferentially with a pitch of approximately 20 degrees. The collagen fibers of the media travel perpendicular to the muscle cells, and parallel to the long axis of the artery. The fibrillar components of the elastin in the intima had a diameter of approximately 700-1000 A and were arranged parallel to the long axis of the artery. It was postulated that the fibrillar part of the elastin was the elastic component of the elastin.     

Ultrastructural and immunohistochemical study of experimental atherosclerosis in Japanese quails

A marked plaque was produced at the tunica intima of the ascending aorta in all of the Japanese quails of 9 weeks old which fed on atherogenic diet containing 2% cholesterol for 8 weeks, while no structural changes of aortic wall were observed in Japanese quails which fed on normal basic food for the same period. The media of aorta in normal quails consist of smooth muscle cells, myofibroblast-like cells (MF) cells), and many successive elastic membranes. At the atherosclerotic lesion, many MF cells migrated from media into intima, and a part of smooth muscle cells were also differentiated to MF cells. Moreover, the most migrating MF cells differentiated to foam cells at the intimal thickness regions, and a few other MF cells also differentiated into endothelial cells of newly forming capillaries. By the immunohistochemical stainings, medial smooth muscle cells were negatively stained with anti-vimentin antibody, and the majority of cells in the intima (MF cells, foam cells, and endothelial cells) contained vimentin filaments. These results indicate that MF cells play a very important role in the development of atherosclerosis in Japanese quail. The morphologicals study offers some new insights into the evaluation of Japanese quails as an animal model of atherosclerosis.     

Localization of dopamine D1 and D2 receptor mRNAs in the rat systemic and pulmonary vasculatures.

The present study was designed to evaluate the expression of dopamine D1 and D2 receptor mRNAs in systemic and pulmonary vasculatures. Using specific antisense riboprobes for dopamine D1 and D2 receptor cDNAs, in situ hybridization histochemistry was performed in the aorta, common carotid artery, vertebral artery, pulmonary artery, and superior vena cava of the adult male Sprague Dawley rat. In the case of the aorta, common carotid artery, and vertebral artery, dopamine D1 receptor mRNAs localized mainly in the smooth muscle cells of the tunica media. However, the signals of dopamine D2 receptor mRNAs were found in the endothelium and subendothelial layer of tunica intima, and interstitial cells of tunica adventitia. In the case of the pulmonary artery, signals of dopamine D1 receptor mRNAs were detected within the tunica intima, media, and adventitia. Expression of D2 receptor mRNAs was detected in the walls of small blood vessels within the tunica adventitia of the pulmonary artery. There were no detectable signals of dopamine D1 and D2 receptor mRNAs in the vein. The uneven distribution of dopamine D1 and D2 receptor mRNAs in the rat systemic vasculatures and pulmonary artery suggests that dopamine differentially regulates the vasodilation of the systemic and pulmonary arteries through the differential stimulation of dopamine D1 and D2 receptor.     

A morphological comparison of aortic elastin from five species as seen with the scanning electron microscope

The elastic laminae were extracted from thoracic aortas of adult animals including sheep, dogs, rabbits, cats and rats by treating them in hot alkaline solution (0.1 N NaOH at 75 degrees C) and observed with a scanning electron microscope. The elastic laminae are comprised of sheet-like internal elastic lamina, fibrous and membraneous elastin in tunica media, interlamellar fibers and hollow spaces which we presume were formerly filled with smooth muscle cells in the tunica media. These structures are the same in all five species except that the number of layers and the total thickness of the wall differs.     

Interstitial flow through the internal elastic lamina affects shear stress on arterial smooth muscle cells

Interstitial flow through the tunica media of an artery wall in the presence of the internal elastic lamina (IEL), which separates it from the subendothelial intima, has been studied numerically. A two-dimensional analysis applying the Brinkman model as the governing equation for the porous media flow field was performed. In the numerical simulation, the IEL was modeled as an impermeable barrier to water flux, except for the fenestral pores, which were uniformly distributed over the IEL. The tunica media was modeled as a heterogeneous medium composed of a periodic array of cylindrical smooth muscle cells (SMCs) embedded in a fiber matrix simulating the interstitial proteoglycan and collagen fibers. A series of calculations was conducted by varying the physical parameters describing the problem: the area fraction of the fenestral pore (0. 001-0.036), the diameter of the fenestral pore (0.4-4.0 microm), and the distance between the IEL and the nearest SMC (0.2-0.8 microm). The results indicate that the value of the average shear stress around the circumference of the SMC in the immediate vicinity of the fenestral pore could be as much as 100 times greater than that around an SMC in the fully developed interstitial flow region away from the IEL. These high shear stresses can affect SMC physiological function.     

SEM observations of the elastic networks in canine femoral artery

Scanning electron microscopy was used to study the normal architectural arrangement of elastic tissue in a medium-sized muscular artery. Selective NaOH sonication digestion or formic acid digestion was used to expose and isolate the elastic networks in the femoral arteries of four healthy dogs. The digested segments were neutralized and freeze-dried before mounting for scanning electron microscopy (SEM) observation. The fenestrated internal elastic lamina (IEL) had a smooth surface with scattered regions of the fine elastic fibers that made up lacy networks protruding from the luminal surface. Prominent ellipsoid fenestrae, randomly scattered across the surface, were grouped into small and large sizes based on their mean diameter. The openings of most fenestrae were bridged by elastic fibers to give the fenestrae a sieve-like appearance. Large, transversely oriented, fusiform gaps were randomly scattered along the length of the IEL. These gaps, filled in by an elastic fiber network, sometimes spanned as much as a quarter of the vessel circumference. It is suggested that these gaps represent splits in the IEL that have been repaired. The tunica media contained a complex network of anastomosing elastic fibers and lamellae that were primarily circumferential in orientation. A well-defined external elastic lamina formed a solid sheet at the junction of the tunica media and the tunica adventitia. The tunica adventitia contained 8-10 incomplete lamellae of large, interconnecting, longitudinally oriented fibers. The architecture of the elastic network in canine femoral artery was compared with that previously described in medium-sized canine veins and in the rat femoral artery.     

Predictive Factors of Late Venous Aortocoronary Graft Failure: Ultrastructural Studies

Background

Venous aortocoronary graft arterialization may precede a preterm occlusion in some coronary artery bypass grafting (CABG) patients. The aim of the present study was to identify ultrastructural variations in the saphenous vein wall that may have an impact on the development of venous graft disease in CABG patients.

Methods

The study involved 365 consecutive patients with a mean age of 62.9±9.4 years who underwent isolated CABG. The thickness and area of the whole venous wall, the tunica intima, the tunica media and the adventitia and the number and shape (length, thickness and length/thickness ratio) of the nuclei in the medial smooth muscle cells nuclei in the distal saphenous vein segments were evaluated by ultrastructural studies. Patients were followed up for 41 to 50 months (mean 45.1±5.1). Saphenous vein graft patency was assessed by follow-up coronary angiography. Logistic regression models were used to identify independent risk factors for late graft failure.

Results

In 71 patients significant lesions in the saphenous vein grafts were observed. The whole venous wall thickness (437.5 µm vs. 405.5 µm), tunica media thickness (257.2 µm vs. 211.5 µm), whole venous wall area (2.23 mm² vs. 2.02 mm²) and tunica media area (1.09 mm² vs. 0.93 mm²) were significantly larger for this group of patients than for those without graft disease. In the latter group more elongated smooth muscle cell nuclei (higher length/thickness ratio) were found in the tunica media of the saphenous vein segments. Thickening of the saphenous vein tunica media and chunky smooth muscle cell nuclei were identified as independent risk factors for graft disease development.

Conclusions

Saphenous vein tunica media hypertrophy (resulting in wall thickening) and chunky smooth muscle cell nuclei might predict the development of venous graft disease.     

Histological study on the arterial wall of G?ttingen miniature swine

In order to clarify the histological aspects of arterial walls of miniature swine, 41 arterial segments removed from each of 17 G?ttingen miniature swines/csk at 6-12 months after birth were examined by light microscopy. Every segment was classified into three types--elastic, transitional, and muscular--according to its histological architecture. Each type was identified on the basis of relative volume and disposition of elastic tissues, collagenous fibers, and smooth muscles in three coats, Tunica intima, Tunica media, Tunica externa. The distribution of each type was demonstrated in a transition from the elastic to the muscular type. The transitional type was designated as a representative type of artery in transitional regions between elastic and muscular types and had some characteristic structures like a mixture of both of them. This type also had longer regions in the back district with the heart as the starting point, such as the Aorta abdominalis, than that of the front. Every artery belonging to the three types had some different structures at different levels, respectively. It was supposed that the histological arrangement of tissues in the walls of a vessel from various parts of the arterial tree would respond properly to the functional demand.     

Differentiation of the smooth muscle cell phenotypes during embryonic development of coronary vessels in the rat

Smooth muscle cell (SMC) maturation during embryonic development of coronary arteries and veins was studied in rats using different markers of the contractile phenotypes. The spatio-temporal pattern of distribution of these markers compared with the developing tunica media was examined. Alpha-smooth muscle actin (alpha-SMA) was the first marker of the SMC in the tunica media of coronary arteries found in ED16 hearts, followed by smooth muscle myosin heavy chain isoform which occurred on ED17. Subsequently 1E12 antigen was expressed in coronary artery wall in ED18 hearts, and finally smoothelin. The markers occur within the proximal part of the coronary arteries and deploy toward the apex. They are also found within the great vessels. None of the markers except for the alpha-SMA were found in coronary veins during embryonic life. We conclude that the SMC population of the developing tunica media of coronary vessels differentiates by the acquisition of particular markers and this process lasts till the end of the prenatal and early postnatal life.     

The association of medial collagenous tissue with atheroma formation in the aging human aorta as revealed by a special technique

A new technique which brilliantly colors collagen fibers in a field of polarized light reveals that during mid-life the smooth muscle cells in the tunica media of the human aorta begin to disappear. The connective tissue is divided between two regions; one below the subintimal layer and the other under the adventitia. Fine collagen fibers extend upward from the former into the subintima and beyond into the intima and the overlying atheromatous plaques of the aging aorta. Thus, the source of fibrous thickening of the vessel is not confined solely to the intimal layer; at least, a portion of the total collagen content arises deep within the aortic wall.     

The three-dimensional structure of the tunica intima and tunica media of the human fetal aorta studied by a new method]

A new method is developed for revealing the latent surfaces in the structure of organs by scanning electronic microscopy. The method is based on the treatment of specimens with potassium ethoxide until cells start to appear in the dissociating solution. Using this method, thoracic aorta of nine human fetuses at the stage of 20-28 weeks was studied. Subendothelial intima and media of human fetal aorta contain smooth muscle cells differing by their arrangement, shape and surface microrelief. The intima cells are arranged in a mosaic pattern formed of single cells or cell clusters. By means of cell processes they are connected with each other, as well as with endothelial and smooth muscle cells of the media. Smooth muscle cells in the inner part of the media also have processes and form an open network. Part of the cells penetrate the intima through pores of the inner elastic membrane. In the deeper layers of the media, laterally adjoining spindle-shaped smooth muscle cells are found. It is suggested that the observed cell polymorphism is due mostly to penetration of the media smooth muscle cells into subendothelium and modification of their shape under the effect of the microenvironment.     

Neuronal systems immunoreactive with antiserum to lamprey gonadotropin-releasing hormone in the brain of Petromyzon marinus

Summary The wall structure of arteriovenous anastomoses in the rabbit ear was investigated. (1) Clusters of epithelioid smooth muscle cells form 3–4 longitudinally oriented plicae. The channel shows a single, irregularly outlined lumen, and its wall is very thin between adjacent plicae. (2) Endothelial cells covering the plicae protrude into the lumen, thus suggesting active contraction or shortening of the plicae. (3) The tunica adventitia is composed of 4–6 sheaths of flat fibroblasts, which may serve as a barrier to prevent loss of neurotransmitters. Processes of some of the fibroblasts also extend into the tunica media. (4) The tunica media is composed of an outer circular layer of typical smooth muscle cells, and an inner longitudinally running plica of ramified smooth muscle cells. Wide intercellular spaces between these ramified cells are filled with collagen fibrils, microfibrils, amorphous intercellular substances, and fibroblasts. Fibroblasts form close membrane contacts with each other, and with the smooth muscle cells. (5) Fibroblasts and other connective tissue components may function as an elastic support during active motility of the anastomotic channel.     

The three-dimensional architecture of the elastic-fiber network in canine hepatic portal system

The architectural arrangement of the elastic-fiber network in the wall of canine hepatic portal veins was observed with the scanning electron microscope (SEM). Selective NaOH sonication digestion and autoclaving were used to expose and isolate the networks of elastic fibers from six selected regions of the hepatic portal vessels from seven healthy dogs. Elastic stains of adjacent segments prepared for light microscopy demonstrated that the elastic fibers were concentrated in two areas within the intact portal wall. The innermost area corresponded to the internal elastic lamina (IEL) of the tunica intima, the internal muscular layer, and the connective tissue layer of the tunica media. The second area was in the tunica adventitia. SEM specimens revealed two sleeves of elastic fiber networks which corresponded to the above regions. Small scattered bundles of radially oriented elastic fibers spanned the gap between the two sleeves. Each tunica had a different architectural arrangement of elastic fibers. The IEL had circumferentially oriented fibers which branched and anastomosed to form a continuous network on the innermost surface. The architecture of the IEL was the most variable between the different regions. The network of the IEL was the most "open" in the caudal region (splenic vein) and became "denser" toward the liver. The large elastic fibers in the tunica media were oriented at approximately right angles to the primary fibers of the IEL. These longitudinally oriented fibers anastomosed with adjacent longitudinal fibers to form a continuous network. In the tunica adventitia, thick, longitudinally oriented fibers of the continuous network fused together to form incomplete layers of fibers. The architecture of the elastic-fiber network in the canine hepatic portal vein was compared to that previously described in the systemic canine saphenous vein.     

中华蟾蜍颈动脉腺的组织学结构

2005年10月～2006年5月,用组织学技术研究中华蟾蜍颈动脉腺结构。结果表明,颈动脉腺位于外颈动脉基部,圆球形,深红色至棕褐色。组织结构显示：颈动脉腺的外壁是动脉管壁的延续,包括外膜、中膜和内膜。整个外壁厚薄不均。颈动脉腺的最大特点是中膜和内膜并不像一般血管形成环圈状,而是从不同部位向管腔突出延伸、相互连接构成大小不一、形状各异、迂回曲折的网状血管。管腔大者,管壁厚,弹性纤维、平滑肌纤维多,内膜靠腔面内皮细胞多成立方状,细胞核端位近圆形;管腔小者,管壁薄,弹性纤维、平滑肌纤维少,内皮细胞扁平、排列稀疏,胞核长梭形;一些区域管径极小,管壁极薄,成为开放的血窦,只允许一个血细胞通过。网状管壁间有密集成团的大型类上皮细胞等细胞分布。据结构推测中华蟾蜍颈动脉腺有调节血压等功能。     

Smoothelin in adult and developing human arteries and myocardium

The aim of this investigation was to study, with immunohistochemical methods, the distribution of the novel cytoskeletal protein smoothelin in human cardiovascular tissues, the possible changes during the development of the cardiovascular system and its correlation to the intermediate filament proteins desmin and vimentin. Smoothelin was detected in smooth muscle cells of the fetal coronary arteries. In very young subjects (up to 3 months of age), only a few cells in the media of the elastic arteries contained smoothelin, whereas it was present in most smooth muscle cells in the muscular arteries. In individuals older than 1 year, most smooth muscle cells in the media of all blood vessels contained smoothelin. In vessels with a developed intima, smoothelin was present in a variable proportion of the smooth muscle cells. With few exceptions, smoothelin was more frequently detected than desmin in medial smooth muscle cells. Smoothelin and vimentin were codistributed in the smooth muscle cells of the media in most vessels. In the cardiomyocytes (fetal to adult age), the smoothelin antibody detected epitopes located at the Z-disc level but not in the intercalated discs. In conclusion, smoothelin is more widely distributed in the muscular arteries than in the elastic arteries early in life, and thus exhibits a variable distribution during postnatal development of vascular tissues. In the adult, smoothelin is detected in the media of most vascular smooth muscle cells, both in muscular and elastic arteries, and is not necessarily codistributed with either desmin or vimentin. Evidence that smoothelin is present in human striated cardiomyocytes is also presented. Accepted: 16 July 1999     

Microscopic anatomy of the thin-walled vessels leaving the heart of the lobster Homarus americanus: anterior median artery

Abstract. The anterior median artery is an unpaired vessel that leaves the anterior end of the lobster ( Homarus americanus ) heart and supplies hemolymph to the brain, the antennae, and the eyestalks. This vessel has a trilaminar organization, consisting of a tunica interna with elastic fibrils, a tunica intermedia represented by a bilayered cell mass, and a tunica externa with collagen fibrils. The exposed ends of the medial cells in the tunica intermedia exhibit small, diffuse bundles of microfilaments that are penetrated by microtubules. These bundles have a circumferential or a slightly oblique orientation relative to the lumen of the vessel. The precise role of the microfilaments is unresolved. If the irregularly shaped bundles are static structures, they might contribute to the non-linear elasticity of the artery. Alternatively, if they generate force, a coordinated contraction of the medial cells might reduce the luminal diameter of the artery and, thus, retard hemolymph flow. Microfilaments of the medial cells anchor to subplasmalemmal filamentous mats, some of which are integral to intermediate junctions and some of which are associated with unbounded cell membranes (hemi-intermediate junctions). Contraction of the microfilament-bearing cells would have to occur without the benefit of nervous innervation or the participation of communicating (gap) junctions. If cell contractility is confirmed, a reclassification of the anterior median artery, from capacitance vessel to resistance vessel, is in order, and the bilayered cell mass in the tunica intermedia would likely qualify as the first unstriated muscle found in crustaceans.     

Smooth muscle cells in the walls of ovarian follicles in the Japanese quail

Summary The walls of pre-ovulatory follicles of the Japanese quail were examined at the ultrastructural level for the presence of cells displaying the typical morphological features of smooth muscle cells. These characteristics were found in the cells of the chordae, the tunica albuginea, and the theca externa. Small, elongated cells, containing microfilaments, were observed in the theca of prelampbrush follicles localized in the ovarian cortex. These thecal cells were considered as the putative precursors of the thecal smooth muscle cells of the pre-ovulatory follicle. The difference between the smooth muscle cells of the pre-ovulatory follicle and those in the wall of the most recent post-ovulatory follicle is the contracted state of the latter, which is most evident in the cells of the theca externa. It can be concluded that the cells of the theca externa are smooth muscle cells which are mainly contracted during the ovulatory process. A comparison was made with other vertebrate species.     

Microscopic studies on the transition between the sigmoid sinus, the superior bulb of the jugular vein and the first portion of the internal jugular vein

The author studied the structure of the tissue components of the tunicae of the terminal segment of the sigmoid sinus, particularly at the level of the transition between the sigmoid sinus, the superior bulb of the jugular vein and the first portion of the human internal jugular vein; it was established that the transition between the sigmoid sinus and the first portion of the internal jugular vein occupies the whole extension of the superior bulb of the jugular vein up to the inferior third of the first portion of this vessel. These vascular walls exhibit a structure similar to that of the dura, i.e. the tunica adventitia is formed by fascicles of collagenic fibers which describe discontinuous spirals, more open proximal to the beginning of the first portion of the internal jugular vein. Approximately in the inferior third of the first portion of the internal jugular vein, there appear fascicles of smooth muscle fibers which are arranged similarly to those of the venous walls. The tunica intima of these vascular segments exhibits an endothelium resting on a network of elastic fibers which may play the role of an internal elastic lamina. From the bony border of the jugular foramen there originates a connective system whose fascicles of collagenic and elastic fibers incorporate to the wall of the internal jugular vein after describing a stretch in spiral around the vascular lumen.     

Immunohistochemical and ultrastructural study of aortic lesions in fat-fed quails

A total of 13 forty-day-old male Japanese quails had free access to a atherogenic diet containing 15% corn oil and 2% cholesterol or commercial basal diet for 3 months. Birds fed basal diet showed no significant intimal lesions. These birds had two types of cells, i.e. smooth muscle cell and fibroblast-like cell, in the tunica media of the ascending aorta. While fat-fed birds showed marked lipid-rich intimal lesions in the ascending aorta but not in the abdominal aorta. Some macrophage-derived foam cells, which were stained for lysozyme and OKM1, were demonstrated in the superficial portion of the thickened intima. The majority of the cells in the lipid-rich thickened intima showed ultrastructural character of fibroblast-like cells with or without lipid droplets. Alpha-1-antichymotrypsin was positive for fibroblast-like cells in the thickened intima but not for those in the tunica media of the ascending aorta. These results suggest that metaplasia of the medial fibroblast-like cells is responsible for the development of atherosclerosis in the quail.