Corrosion Cast Technique Research Articles

Morphological features of the spermatic cord in the musk shrew (Suncus murinus) with special reference to extratesticular Leydig cells.

Morphological features of the testicular artery and vein in the spermatic cord of the musk shrew (Suncus murinus) were evaluated by light microscopy, transmission electron microscopy, corrosion cast technique combined with scanning electron microscopy and immunohistochemistry. The vascular architecture in the spermatic cord of the musk shrew was simple. The testicular artery in the musk shrew was straight and accompanied by 1 to 3 branches of testicular vein. The testicular vein was also straight and anastomosed with each other in some points along its length, but it did not form a delicate pampiniform plexus. In the middle and distal portions of the spermatic cord, the tunica adventitia of the artery and vein was joined together to form a single connective tissue septum. Clusters of cells were found in this connective tissue septum in the middle portion of the cord. These cells were located close to the arterial wall and nerve endings, but they did not appear inside of neurium. They showed several typical characteristics similar to Leydig cells, and they were positive for 3beta hydroxysteroid dehydrogenase (HSD) antibody. Ultrastructural and immunohistochemical studies also indicated that the cells in cluster found in the vascular wall of the musk shrew spermatic cord may be equivalent to Leydig cells in testes. These extratesticular Leydig cells had characteristics of the active steroid-producing cell and seemed to be another source of testosterone.

Angioarchitecture of the coeliac sympathetic ganglion complex in the common tree shrew (Tupaia glis).

The angioarchitecture of the coeliac sympathetic ganglion complex (CGC) of the common tree shrew (Tupaia glis) was studied by the vascular corrosion cast technique in conjunction with scanning electron microscopy. The CGC of the tree shrew was found to be a highly vascularised organ. It normally received arterial blood supply from branches of the inferior phrenic, superior suprarenal and inferior suprarenal arteries and of the abdominal aorta. In some animals, its blood supply was also derived from branches of the middle suprarenal arteries, coeliac artery, superior mesenteric artery and lumbar arteries. These arteries penetrated the ganglion at variable points and in slightly different patterns. They gave off peripheral branches to form a subcapsular capillary plexus while their main trunks traversed deeply into the inner part before branching into the densely packed intraganglionic capillary networks. The capillaries merged to form venules before draining into collecting veins at the peripheral region of the ganglion complex. Finally, the veins coursed to the dorsal aspect of the ganglion to drain into the renal and inferior phrenic veins and the inferior vena cava. The capillaries on the coeliac ganglion complex do not possess fenestrations.

Microcirculation of human fetal posterior root ganglia: a scanning electron microscopic study of corrosion casts

The vasculature of lumbar posterior root ganglia was investigated in human fetuses aged 17-24 weeks; using the corrosion casting technique and scanning electron microscopy. The arterial supply consisted of one main artery and occasional arterioles entering the ganglion at its pole and running axially, while the venous drainage was located at the periphery of the ganglion, thus indicating a centrifugal pattern of blood flow. The dense capillary network of the ganglion showed the roughly parallel course of the vessels in the central zone and an irregular arrangement in the peripheral zone where capillaries formed "nests", probably surrounding individual perikaryons of ganglionic cells. The capillaries had a sinusoidal character with numerous dilatations about twice the normal capillary size, as well as occasional larger vascular spaces resulting from capillary interconnections and suggesting the intussusceptive type of angiogenesis.

Three-dimensional analysis of vasospastic major cerebral arteries in rats with the corrosion cast technique.

Although mice, rats, and other small animals are commonly used for molecular biology research, their use in the evaluation of cerebral vasospasm after subarachnoid hemorrhage is somewhat problematic because of the correspondingly small size of their cerebral vessels. We have already reported that the corrosion cast technique was useful for evaluating newly formed cerebral vessels in neural grafts in these small animals. In the present study we applied the corrosion cast technique to the evaluation of hemolysate-induced cerebral vasospasm in rats and performed three-dimensional analysis for comparison. The casting was done 10 minutes after the hemolysate injection, so that only acute "vasospasm" was assessed. After withdrawal of 0.1 mL cerebrospinal fluid, 0.2 mL hemolysate (n = 9) or saline (n = 10) was injected into the cisterna magna of male Sprague-Dawley rats weighing between 300 and 350 g. Ten minutes later, perfusion of a semipolymerized casting medium was performed at an injection pressure of 100 to 120 mm Hg. The brains were immersed and corroded in 10% NaOH solution. After these procedures, the basilar artery as well as peripheral vessels was analyzed morphologically with scanning electron microscopy. Conventional histological analysis with the use of paraffin-embedded section with hematoxylin-eosin staining was also performed, and the results were compared with those for the corrosion cast methods. In the saline-injected group, SEM showed that the inner surface of the basilar artery was smooth and the form of the endothelial cell was printed on the surface of the cast. In the hemolysate-injected group, the basilar artery showed an apparent vasospasm over its entire length, and corrugation was observed on the inner surface of the basilar artery in a three-dimensional fashion. Higher magnification revealed that the nuclei of the endothelial cells were distorted. Local narrowing of the basilar artery and vasospasm in the arteries of the anterior circulation and in peripheral arteries were also observed. Measurement of the inner diameter of the basilar artery showed 37.8% contraction in the hemolysate-injected group compared with the saline-injected group by the corrosion cast method. This degree of vasospasm was similar to that observed by the conventional histological method. In this report we show that detailed three-dimensional observation in the rat can be performed qualitatively and quantitatively with the corrosion cast technique. We conclude that this method derives an accurate measurement of the diameter of rat major cerebral arteries and is more reliable for analyzing vasospasm in rats than angiography and other conventional procedures.

Corrosion casts of the suprachoroidal space and uveoscleral drainage routes in the human eye.

Human cadaver eyes were studied by corrosion casting technique. Batson's mixture No. 17 (methyl methacrylate) was injected through a sclerotomy into the suprachoroidal space. Following polymerisation of the injected mixture the surrounding tissue was dissolved with 10% natrium hydroxide. Macroscopic and scanning electron microscopic findings in casts of the suprachoroidal space are presented. Due to transscleral drainage of resin from the suprachoroidal space, different types of branches deriving from the outer (scleral) surface of the casts were found. Some of these branches corresponded to the perivascular spaces of both ciliary vessels and vortex veins. In addition, we found branches probably representing channels deriving directly from the suprachoroidal space, communicating with the intrascleral venous plexus. Such channel systems have previously not been described, and their possible relation to the uveoscleral drainage of aqueous humour is discussed.

Corrosion casts of the suprachoroidal space and uveoscleral drainage routes in the pig eye.

Eyes from pigs were studied by corrosion casting technique. Batson's mixture No. 17 (methyl methacrylate) was injected through a sclerotomy into the suprachoroidal space. Following polymerisation of the injected mixture the surrounding tissue was dissolved with 10% natrium hydroxide. Macroscopic and scanning electron microscopic findings in casts of the suprachoroidal space are presented. The outer (scleral) surface of the casts was rough, with a fish-scale-like appearance caused by fine lamellas between the sclera and choroid, running from the inner layers of the sclera traversing the space anteriorly to the choroid. Frequently, irregular, Y-shaped branches deriving from the outer surface of the casts were observed. They corresponded to the perivascular space of the vortex veins and represent a possible uveoscleral drainage route for aqueous humour.

Microvasculature of the gastric mucosa in dogs.

A corrosion casting technique was used to study differences in the microvascular architecture of the pars cardiaca, the fundus ventriculi, the corpus ventriculi and the pars pylorica of the canine gastric mucosa. This technique revealed an unusual arrangement of the microvascular architecture in the nonglandular region surrounding the esophageal opening. Capillaries run tortuously along the mucosal surface parallel to the long axis of the esophagus, and some capillaries form a polygonal network that extends around the seromucous glands. In contrast, the mucosal capillaries of the glandular regions of the stomach are arranged in a symmetric pattern associated with the gastric glands. There are also differences in the mucosal microvessels of the cardiac and fundic areas compared to the corpus and the antrum. In the cardiac and fundic regions, a sparse microvascular pattern was observed and fewer capillaries drained into a single venule. However, the vessels surrounding the gastric glands in the corpus and antral areas drained into venules perpendicular to the hexagonal arrangement of the capillaries.

Microvascularization in trigeminal ganglion of the common tree shrew (Tupaia glis).

Since there is only a limited number of studies of the blood supply to the trigeminal ganglion (TG) in mammalian species, the TG from 16 common tree shrews (Tupaia glis) were investigated by light microscope, transmission electron microscope (TEM) and the corrosion cast technique in conjunction with scanning electron microscope (SEM). It was found that the TG contained clusters of neurons in the peripheral region whereas the bundles of nerve fibers were located more centrally. Each ganglionic neuron had a concentric nucleus and was ensheathed by satellite cells. It was noted that blood vessels of a continuous type were predominantly found in the area where the neurons were densely located and were much less frequently observed in the area occupied by nerve fibers. With TEM, the TG was shown to be mainly associated with large neurons containing big nuclei and prominent nucleoli. The blood supply of the TG is derived from the most rostral branch of the pontine artery, from the stapedial artery or sometimes from the supraorbital artery, and from the accessory meningeal artery which is a branch of the maxillary artery passing through the foramen ovale. These arteries give off branches and become capillary networks in the ganglion before draining blood to the peripheral region. The veins at the medial border drained into the cavernous sinus directly or through the inferior hypophyseal vein, while those at the lateral side of the ganglion carried the blood into the pterygoid plexus via an accessory meningeal vein. The veins along the trigeminal nerve root joined the posterior part of the cavernous sinus. These studies establish a unique anatomical distribution of the TG blood supply in the tree shrew and the utility of the cast/SEM technique in discerning detailed features of the blood supply in the nervous system.

Liver metabolic zonation and hepatic microcirculation in carbon tetrachloride-induced experimental cirrhosis.

The exact cause of the hepatic failure in liver cirrhosis is currently unclear, and two main theories have been proposed: the first is based on the altered hepatocyte function (sick hepatocyte hypothesis); the second on the abnormal hepatic architecture (intact hepatocyte hypothesis). Moreover, the microcirculation, a fundamental component in liver structure, shows dramatic changes in cirrhosis that would heavily influence the development of the disease. In order to determine the importance of the microvascular alterations on liver morphofunctional features in experimentally induced cirrhosis, their relationships with structural, ultrastructural, and histoenzymological hepatocyte modifications were investigated. Experimental cirrhosis was induced with controlled intragastric CCl4 administration. Scanning electron microscopy of the vascular corrosion cast technique, associated with light microscopy, transmission electron microscopy, and histoenzymology techniques were employed. The results demonstrated a characteristic micronodular cirrhosis in all the livers studied; the microcirculation displayed the presence of newly formed perinodular plexus. Inside the nodule, areas with two or more hepatocyte-thick laminae were present. Moreover, a rearrangement of the hepatocyte quantitative ultrastructure without real pathological changes and a loss of normal metabolic lobular zonation were noted in the liver parenchyma. These findings support the concept that the progressive modifications of the microcirculation during experimental CC14 cirrhosis modify not only the normal blood flow direction, but also the normal hepatic metabolic gradient with a loss of the normal hepatocytic zonation.

Hepatic microcirculation and peribiliary plexus in experimental biliary cirrhosis: A morphological study

BACKGROUND & AIMS: The peribiliary plexus plays a fundamental role in supporting the secretory and absorptive functions of biliary epithelium. Little information is available on the rearrangement of the peribiliary plexus during conditions associated with ductular proliferation. This study investigated the chronological modulation of bile duct and peribiliary plexus proliferation after common bile duct ligation in the rat. METHODS: Light microscopy and scanning electron microscopy vascular corrosion cast technique was used to study the architecture of the peribiliary plexus in rats with 1, 2, and 4 weeks of common bile duct ligation or in sham-operated controls. RESULTS: After 1 week of common bile duct ligation, no evident change of hepatic microvasculature was observed despite significant proliferation of bile ducts. After 2 and 4 weeks, significant microvasculature proliferation was observed extending from the peribiliary plexus of bile tracts. Vascular proliferation coincides with the extension of portal tract connective tissue. No evidence of vascular proliferation or other morphological modifications was present at the level of sinusoids around the portal tracts. CONCLUSIONS: After common bile duct ligation, the peribillary plexus undergoes marked proliferation, thus supporting the increased nutritional and functional demands from the proliferated bile ductal system. However, the proliferation of the peribillary plexus only occurs after that of the bile ductal system. (Gastroenterology 1996 Oct;111(4):1118-24)

Optic nerve vasomotor effects of topical apraclonidine hydrochloride.

To examine, in vivo, the anterior optic nerve vasomotor effects of chronic apraclonidine hydrochloride in rabbits. After local treatment in one randomly chosen eye with apraclonidine hydrochloride 0.5% over 21 days, the microvasculature of the optic nerve was examined in five rabbits using an intraluminal microvascular corrosion casting technique. The investigators were masked as to which eye was treated. The vasoconstriction near the branching point of arterioles supplying the optic nerve was calculated as a percentage of the downstream vessel calibre. An average constriction was calculated and compared between the treated and the contralateral, untreated, eyes by means of a two tailed t test for paired variables. Constriction values of a total of 72 arterioles supplying the optic nerve were obtained for the five rabbits. The average constriction in the treated and the control eyes was comparable (p = 0.96). Chronic administration of apraclonidine hydrochloride 0.5% produces no observable optic nerve vasomotor effects in the rabbit eye.

Optic Nerve Vasomotor Effects of Topical Beta-Adrenergic Antagonists in Rabbits

To examine the anterior optic nerve vasomotor effects of nonselective and relatively beta-1-selective beta-adrenergic antagonists in rabbits, because different influences on optic nerve blood flow with these medications have been suggested. After topical therapy for 30 days with either timolol maleate 0.5% (six rabbits), betaxolol hydrochloride 0.5% (six rabbits), or placebo (two rabbits), the microvasculature of the optic nerve was examined with an intraluminal microvascular corrosion casting technique. The investigators were masked to both the medication group and the treated eye. The constriction, in percent of the downstream vessel caliber, was measured at the vascular branching point of arterioles supplying the anterior optic nerve. An average constriction was calculated and compared between the medication groups and between the treated and the contralateral, untreated eyes. Constriction values from a total of 218 arterioles supplying the anterior optic nerve were obtained for the 14 rabbits. The means of the average constriction on the treated side were comparable between the groups treated with timolol maleate, betaxolol hydrochloride, and placebo (one-way analysis of variance, P = .64), as well as between the treated and untreated eyes (two-tailed t-test for paired variables, P = .68 for timolol maleate and P = .42 for betaxolol hydrochloride). The statistical power to find a difference of 5% or more average constriction was at least 90%. Both relatively selective and nonselective beta-adrenergic antagonists produce no observable optic nerve vasomotor effects in the rabbit eye.

Three-dimensional architecture of human cutaneous vascular lesions: a scanning electron microscopic study of corrosion casts.

Corrosion casts were made from angiosarcoma of the scalp of an elderly person, Klippel-Trenaunay syndrome, pseudo-Kaposi's sarcoma, diffuse neonatal hemangiomatosis, cavernous hemangioma and arteriovenous malformation and were examined by scanning electron microscopy (SEM). The normal scalp from a cadaver was studied as a control for the angiosarcoma of the scalp. the SEM of the vascular corrosion casts clearly demonstrated the fine three-dimensional (3-D) architectures of malignant and benign cutaneous vascular lesions; the superficial fine and medium-sized vascular networks of the skin were replaced by abnormal balloon-like dilatations, extravasated fringes, glomerular structures, sinusoidal vessels or localized bulla-like structures of the capillary loops, depending on the nature of the cutaneous vascular lesions. The corrosion cast technique is helpful for understanding the 3-D patterns of various vascular lesions.

Microvasculature of the Human Optic Nerve

Methyl methacrylate vascular corrosion casting techniques were used to examine the normal anterior optic nerve microvasculature in 18 human eye bank eyes. Selective cannulation of the central retinal artery, the short posterior ciliary arteries, or both, allowed the methyl methacrylate to be injected into the anterior optic nerve circulation. Preflushing with tissue plasminogen activator greatly enhanced the filling of the fine microvasculature by dissolving the intraluminal clots. The superficial nerve fiber layer of the optic nerve received its primary blood supply from the central retinal artery. In 11 of 13 eyes injected with methyl methacrylate through the short posterior ciliary arteries, there was a perineural, circular arterial anastomosis (circle of Zinn-Haller) at the scleral level. Branches from this circle penetrated the optic nerve to supply the prelaminar and laminar regions and the peripapillary choroid. In the two eyes without this arterial circle, direct branches from the short posterior ciliary arteries supplied the anterior optic nerve. The venous drainage of the anterior optic nerve was almost entirely through the central retinal vein and its tributaries. This study demonstrates that the main arterial vascular supply to the anterior optic nerve is from the short posterior ciliary arteries. The contribution of the peripapillary choroid to the anterior optic nerve is minimal in comparison to the direct contribution from the short posterior ciliary arteries.

The coronary arteries of the Garden dormouse ( Eliomys quercinus L., 1766)

The arrangement of the coronary arteries was studied in 18 Garden dormice (4 6@, 1499 ). Most of them (n=17) were examined using a corrosion-cast technique, while the remaining specimen was studied histologically. In the Garden dormouse the heart shows no interventricular grooves, and both the right and left coronary arteries become intramyocardial shortly after their origin from the aorta. The right coronary artery has two principal branches: the right circumflex branch and the dorsal interventricular branch. The conal branch also originates from the main trunk of the right coronary artery. The main branches of the left coronary artery are the left circumflex branch and one or two dorsal ventricular branches. When two dorsal ventricular branches exist, one of them often behaves as an obtuse marginal branch, running along the proximal half of the obtuse margin of the heart; thereafter the vessel turns towards the dorsal wall of the left ventricle. The ventral interventricular branch is sometimes absent. When present, it always rises from the left coronary artery and does not reach the apex of the heart. The ventricular septum is principally supplied by a well-developed septal artery arising from the left coronary artery; thus, the Garden dormouse exhibits a left septal pattern. A less important vascularization of the septum is established through thinner penetrating vessels originating from the right and left coronary arteries.

Anomalous origin of the left coronary artery from the dorsal aortic sinus and its relationship with aortic valve morphology in Syrian hamsters

The condition of the aortic valve and the origin of the coronary arteries were examined in 2413 Syrian hamsters aged between 1 and 823 days, belonging to nine inbred laboratory families. The specimens were studied with either a stereomicroscope, a corrosion-cast technique, or histological techniques (light microscopy). The aortic valve was tricuspid in 1823 (75.5%) cases, and bicuspid in the remaining 590 (24.5%). In all bicuspid aortic valves there were two aortic sinuses, a ventral and a dorsal, each supporting one cusp. The left coronary artery arose from the dorsal aortic sinus in 71 (2.9%) hamsters, eight of which died unexpectedly between ages 1 and 622 days. In 29 (40.8%) of the 71 cases, the aortic valve was tricuspid and the right coronary artery originated from the right aortic sinus. In the remaining 42 (59.2%) cases, the aortic valve was bicuspid and the right coronary artery arose from the right side of the ventral aortic sinus. Results of a chi 2 contingency test demonstrated that the frequency of left coronary artery arising from the dorsal aortic sinus significantly increased when the aortic valve was bicuspid. This fact, together with previously reported data on coronary artery anomalies in the Syrian hamster, suggests that the left coronary artery arising from the dorsal aortic sinus may be an expression of a single morphogenetic defect which is expressed as bicuspid aortic valve in some cases, anomalous origin of the left coronary artery in others, or in the simultaneous occurrence of these two cardiac abnormalities.

An in vivo model of chronic optic nerve ischemia: the dose-dependent effects of endothelin-1 on the optic nerve microvasculature.

The purpose of this study was to evaluate the effects induced by chronic microapplication of endothelin-1 on the anterior optic nerve microvasculature and to determine the dose-response characteristics of endothelin-1 on this vascular bed. Daily dosages between 4.69 x 10(-4) and 9.0 x 10(-1) micrograms/day of endothelin-1 were delivered continually over 3 days, and at a constant flow rate, to the perineural region of the anterior optic nerve of 15 albino rabbits via osmotically-driven minipumps. The vasomotor effect of local endothelin-1 on the microvasculature of the optic nerve was examined using intraluminal microvascular corrosion casting technique. The vasomotor effects were quantified by measuring the relative amount of vasoconstriction of the arterioles supplying the anterior optic nerve (primary and secondary branches of the short posterior ciliary arteries). The average constriction was calculated for the endothelin-treated eyes and the untreated, contralateral eyes. The mean vasoconstriction in the endothelin treated eyes ranged from 14.7% to 30.0% and was highly correlated with the logarithmic value of the daily dose of endothelin-1 (R2 = 0.59, p = 0.00083). The interocular difference (between treated and untreated eyes) of the optic nerve vasoconstriction ranged from 0-19% (mean +/- SD: 7.23 +/- 5.7%). This interocular difference also correlated highly with the log of the daily endothelin-1 dosage (R2 = 0.80; p < 0.0001). By additionally accounting for the weight and sex in a multiple linear regression function, the correlation was markedly improved (R2 = 0.92; p < 0.0001). In conclusion, the microvasculature supplying the anterior optic nerve of the rabbit demonstrates a dose-dependent vasoconstriction with chronic local application of endothelin-1. This in vivo, experimental model offers a titratable method with which the effects of chronic vasoconstriction and vascular insufficiency on the optic nerve can be examined.

Blood vessels in epiphyseal cartilage of human fetal femoral bone: a scanning electron microscopic study of corrosion casts

Formation of intrachondral vessels (cartilage canals) in the proximal femoral epiphysis was studied in 13- to 22-week-old human fetuses using a corrosion casting technique and scanning electron microscopy. Several successive morphological stages of angiogenesis occurring inside the hyaline cartilage were distinguished. The process of cartilage vascularization starts with the formation of hairpin loops sent off from the perichondrial vascular network into the adjacent cartilage. A capillary glomerulus is then formed at the leading end, and the entire vascular unit grows in length, assuming a mushroom-like shape. Its further elongation is accompanied by a backward expansion of the capillary network which surrounds a pair of main vessels (arteriole and venule) like a manchette. The subsequent branching of such primary vascular units proceeds according to the same morphological patterns. The resulting tree-like vascular formations become interconnected via their lateral branches. This study clearly supports the invasion theory of cartilage canal formation.

Vascularization of the pineal gland in the crow.

The blood vascularization in the pineal gland of the crow was investigated in detail using a vascular corrosion cast technique and by scanning electron microscopy. The pineal gland received two afferent arteries on either side, each artery arising from the A. cerebralis caudalis (CC) which supplied its branches to the hemisphere. The pineal gland of the crow was so highly vascularized as to be suggestive of its high metabolic and endocrine activities. The efferent veins drained into the Sinus occipitalis and the Sinus sagittalis dorsalis. There was a direct vascular connection between capillaries of the stalk of the gland and those of the Plexus choroideus.

Vascularization of the pineal complex in the lizard Tiliqua rugosa

The vascularization of the pineal complex in the lizard Tiliqua rugosa was investigated by vascular corrosion and latex casting techniques. The fine structure of the pineal capillaries was also studied by transmission electron microscopy. The pineal complex in T. rugosa consists of an elongated pineal gland proper and a separate, distinct parietal eye. The pineal complex derives an abundant blood supply from branches of the middle and posterior cerebral arteries. Scanning electron microscopy of vascular corrosion casts revealed a dense and extensive pineal capillary bed which drains ultimately into a wide longitudinal sinus suggesting an efficient pathway for the rapid removal of substances secreted by the gland. The parietal eye, which receives a unilateral left-sided blood supply from the unpaired anterior pineal artery, is shown to be a highly vascularized structure. The close morphological relationship between the pineal gland and dorsal sac, where the two structures apparently share the same blood vessels, suggests a functional relationship between them. The pineal capillaries are fenestrated with tight junctions between adjoining endothelial cells. Podia-like abluminal extensions of the endothelial cells were observed in close relation to unmyelinated nerve bundles. The basal margin of the pineal parenchyma is highly invaginated with thin finger-like cytoplasmic protrusions into the pericapillary space. Distinct bands of microfibrils form "struts" anchoring the pineal parenchyma to the endothelial wall. These features may have a role in the transfer of materials between the pineal gland and the blood stream.