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Corrosion Casts (corrosion + cast)
Selected AbstractsMaternal and fetal microvasculature in sheep placenta at several stages of gestationJOURNAL OF ANATOMY, Issue 3 2010Shireen A. Hafez Abstract Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi. [source] Microvasculature of the human cerebral white matter: Arteries of the deep white matterNEUROPATHOLOGY, Issue 2 2003Hiroko Nonaka The vascular architecture of the human cerebral deep white matter was studied using soft X-ray and diaphanized specimens, achieved by intra-arterial injection of barium and vascular stain respectively, and also by electron microscopic examination of the corrosion cast of arteries in normal adult brains. The deep white matter arteries passed through the cerebral cortex with a few branches to the cortex and ran straight through the white matter. The arteries concentrated ventriculopetally to the white matter around the lateral ventricle. Anastomoses were noted around the ventricular wall at the terminals of the deep white matter arteries. No centrifugal branches irrigating the periventricular white matter from the lenticulo-striate arteries were observed in the present study. The presence of anastomoses among the terminal branches of deep white matter arteries protects against ischemic change or infarction in this area from an occlusion of a single deep white matter artery. This may lead to development of terminal zone infarction from ischemia or vascular diseases, affecting multiple deep white matter arteries. The subcortical and deep white matter arteries had thick adventitial sheaths and large adventitial spaces in the white matter but not in the cortex. The presence or absence of the adventitial space is regarded as another characteristic difference between the arteries in the white matter and cortex. This difference may influence pathological changes in vascular lesions in these respective areas. [source] Occlusion of the Middle Cerebral Artery: a New Method of Focal Cerebral Ischemia in RatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005E. Cam The study in Wistar rats attempted to improve the occlusion technique of the middle cerebral artery (MCA) as a precise method for initiating stroke. In a first part it was necessary to study the exact anatomy of blood vessels of the brain in seven rats of 170-410 g body weight by corrosion cast. The lengths and diameters of defined locations of the blood vessels were measured. The temporary as well as the permanent methods were refined or replaced. The first one was completed in main training the physiological blood flow after temporary occlusion, while the permanent occlusion was performed by positioning a silicone cap in the MCA. A filament guide was introduced from the common carotid artery (CCA) via internal carotid artery (ICA) to guide the silicon cap at the branch of the MCA. Histological sections of the brain of rats showed 24 h after the permanent occlusion a reproducible infarct in the brain. This area corresponded very well with the supply of the MCA. The new occlusion method with a silicon cap was compared with the occlusion methods of CCA route and external carotid artery (ECA) route. The total infarct volume was significantly larger in the CCA route and ECA route groups than in the silicon cap group (means: CCA route 261 mm3; ECA route 191 mm3 vs. 128 mm3 silicon cap group; P < 0,05). It could be demonstrated that the new silicon cap occlusion technique imitates the pathological situation of a cerebral infarct in man. Moreover it is less invasive for the animals and more precise and reproducible regarding the infarcted area in comparison to the other occlusion methods. Based on anatomical measurements of the blood vessels the described silicon cap method can be recommended for rats of a body weight between 340,370 g. [source] Bilateral tentorial sinus drainage of the basal vein (of Rosenthal)CLINICAL ANATOMY, Issue 3 2003Diego San Millán Ruíz Abstract We report a case of bilateral collateral tentorial venous sinus drainage of the basal vein (of Rosenthal) (BV). The observation was made on a corrosion cast of the cerebral venous system obtained from a fresh cadaver. Radiographic correlation was obtained by performing standard X-ray imaging of the corrosion cast. Embryologic and clinical considerations are discussed. Clin. Anat. 16:264,268, 2003. © 2003 Wiley-Liss, Inc. [source] Validation of the murine aortic arch as a model to study human vascular diseasesJOURNAL OF ANATOMY, Issue 5 2010Christophe Casteleyn Abstract Although the murine thoracic aorta and its main branches are widely studied to gain more insight into the pathogenesis of human vascular diseases, detailed anatomical data on the murine aorta are sparse. Moreover, comparative studies between mice and men focusing on the topography and geometry of the heart and aorta are lacking. As this hampers the validation of murine vascular models, the branching pattern of the murine thoracic aorta was examined in 30 vascular corrosion casts. On six casts the intrathoracic position of the heart was compared with that of six younger and six older men of whom contrast-enhanced computer tomography images of the thorax were three-dimensionally reconstructed. In addition, the geometry of the human thoracic aorta was compared with that of the mouse by reconstructing micro-computer tomography images of six murine casts. It was found that the right brachiocephalic trunk, left common carotid artery and left subclavian artery branched subsequently from the aortic arch in both mice and men. The geometry of the branches of the murine aortic arch was quite similar to that of men. In both species the initial segment of the aorta, comprising the ascending aorta, aortic arch and cranial/superior part of the descending aorta, was sigmoidally curved on a cranial/superior view. Although some analogy between the intrathoracic position of the murine and human heart was observed, the murine heart manifestly deviated more ventrally. The major conclusion of this study is that, in both mice and men, the ascending and descending aorta do not lie in a single vertical plane (non-planar aortic geometry). This contrasts clearly with most domestic mammals in which a planar aortic pattern is present. As the vascular branching pattern of the aortic arch is also similar in mice and men, the murine model seems valuable to study human vascular diseases. [source] Maternal and fetal microvasculature in sheep placenta at several stages of gestationJOURNAL OF ANATOMY, Issue 3 2010Shireen A. Hafez Abstract Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi. [source] The petrosquamosal sinus in humansJOURNAL OF ANATOMY, Issue 6 2006Diego San Millán Ruíz Abstract This article provides a comprehensive description of the morphology of the human petrosquamosal sinus (PSS) derived from original observations made on 13 corrosion casts of the cranial venous system combined with routine clinical imaging studies in two patients. The PSS is not a rare finding in the adult human. In particular, continuous developments in imaging techniques have made radiologists become increasingly aware of this anatomical entity in recent years. The role of the PSS as a major encephalic drainage pathway and its potential implication in pathological conditions such as intracranial venous hypertension are discussed. [source] Fractal and Fourier analysis of the hepatic sinusoidal network in normal and cirrhotic rat liverJOURNAL OF ANATOMY, Issue 2 2005Eugenio Gaudio Abstract The organization of the hepatic microvascular network has been widely studied in recent years, especially with regard to cirrhosis. This research has enabled us to recognize the distinctive vascular patterns in the cirrhotic liver, compared with the normal liver, which may explain the cause of liver dysfunction and failure. The aim of this study was to compare normal and cirrhotic rat livers by means of a quantitative mathematical approach based on fractal and Fourier analyses performed on photomicrographs and therefore on discriminant analysis. Vascular corrosion casts of livers belonging to the following three experimental groups were studied by scanning electron microscopy: normal rats, CCl4 -induced cirrhotic rats and cirrhotic rats after ligation of the bile duct. Photomicrographs were taken at a standard magnification; these images were used for the mathematical analysis. Our experimental design found that use of these different analyses reaches an efficiency of over 94%. Our analyses demonstrated a higher complexity of the normal hepatic sinusoidal network in comparison with the cirrhotic network. In particular, the morphological changes were more marked in the animals with bile duct-ligation cirrhosis compared with animals with CCl4 -induced cirrhosis. The present findings based on fractal and Fourier analysis could increase our understanding of the pathophysiological alterations of the liver, and may have a diagnostic value in future clinical research. [source] Theoretical Simulation of Oxygen Transport to Brain by Networks of Microvessels: Effects of Oxygen Supply and Demand on Tissue HypoxiaMICROCIRCULATION, Issue 4 2000T.W. SECOMB ABSTRACT Objective: Simulations of oxygen delivery by a three-dimensional network of microvessels in rat cerebral cortex were used to examine how the distribution of partial pressure of oxygen (PO2) in tissue depends on blood flow and oxygen consumption rates. Methods: Network geometry was deduced from previously published scanning electron micrographs of corrosion casts. A nonlinear least-squares method, using images obtained at three different angles, was used to estimate vessel locations. The network consisted of 50 segments in a region 140 µm × 150 µm × 160 µm. A Green's function method was used to predict the PO2 distribution. Effects of varying perfusion and consumption were examined, relative to a control state with consumption 10 cm3O2/100 g per min and perfusion 160 cm3/100 g per min. Results: In the control state, minimum tissue PO2 was 7 mm Hg. A Krogh-type model with the same density of vessels, but with uniform spacing, predicted a minimum tissue PO2 of 23 mm Hg. For perfusion below 60% of control, tissue hypoxia (PO2 <1 mm Hg) was predicted. When perfusion was reduced by 75%, the resulting hypoxia could be eliminated by a 31% reduction in oxygen consumption rate. Conclusions: The simulations suggest that tissue hypoxia resulting from a severe decrease in brain perfusion, as can occur in stroke, may be avoided by a moderate decrease in oxygen consumption rate. [source] Angiogenesis in the Caprine Caruncles in Non-Pregnant and Pregnant Normal and Swainsonine-Treated DoesTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 7 2007S.A. Hafez Abstract Microvascular corrosion casts of caruncles from non-pregnant and pregnant doe goats at 4, 7, 10, 13, 16, and 18 weeks were examined with scanning electron microscopy. The internal convex surface of the caruncles of non-pregnant does was covered with capillary meshes of regular diameter and form, without crypts. As pregnancy advanced the complexity of the vasculature increased: at 4 weeks the surface showed a pattern of ridges separated by troughs. At later stages, branches of radial arteries penetrated the periphery forming an extensive mesh of capillaries on the concave surface. Capillary diameters increased significantly during pregnancy, especially after 4 weeks, when large flattened sinusoids formed. These sinusoids had a great deal of surface area for potential contact with the fetal component. The caprine placenta is usually considered to have increased interhemal distance compared with endotheliochorial and hemochorial types: our results suggest that the very extensive development of sinusoids and crypts may compensate for any negative consequences of the placental architecture. Placental angiogenesis, which is physiologically normal, may serve as a general model of this process in other circumstances, such as tumor. The effect of swainsonine (active compound of locoweed and a potential anticancer drug) on vascular development showed no differences in sinusoidal diameters at 7 weeks, but a decrease in capillary density was noted. Swainsonine caused a great distortion to the vasculature at 18 weeks. The effects of this compound on the vascular development lend credibility to its potential as an anticancer agent. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Light and Scanning Electron Microscopic Study on the Blood Vascular System of the Donkey PlacentaANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2008A. Saber Summary The donkey placenta is diffuse and epitheliochorial with numerous microplacentomes consisting of a fetal microcotyledonary and a maternal microcaruncular part. The microplacentomal vasculature during the last third of pregnancy has been investigated by light microscopy in comparison to scanning electron microscopy of the materno-fetal contact surface and corrosion casts of blood vessels after plastic instillation from either the microcotyledonary or the microcaruncular side, and, for the first time in a perissodactyle, from both sides. Morphological data were semiquantitatively evaluated. The supplying parts of both, the microcotyledonary and the microcaruncular vascular system are strictly proximo-distally oriented, thus reaching the capillary systems or working parts in the shortest way possible. The straight course of the vasculature, particularly on the fetal side, suggests the occurrence of venulo-arteriolar back diffusion. The fetal capillary system consists of convolutes confronting the maternal septal capillary complexes in a countercurrent way. This materno-fetal blood flow interrelationship is highly efficient in terms of placental exchange, which is further supported (1) by dilations and increasing coiling of the fetal venular capillary limbs in particular and (2) by a decrease in the interhaemal distance from 12.5 to 7.2 ,m between the two capillary systems. Besides the countercurrent blood flow interrelationship, some maternal branch arterioles reach the septal capillary system from the maternally oriented pole of the microplacentome or microcaruncle, respectively, resulting in the less efficient crosscurrent blood flow. Hence, in the donkey placenta fetal and maternal blood vessels meet in a mix of countercurrent and crosscurrent flow patterns. [source] Vascularization of the Fleshy Comb in the Domestic ChickenANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005B. Vollmerhaus Up to now little is known about the vascularization of the chicken fleshy comb (crista carnosa). In order to evaluate the vascularization of the crista carnosa of the cook (breed White Leghorn), corrosion casts were created by injecting Plastoid into the internal carotid as described by Schummer (1951). Specimens were investigated by stereomicroscopy and scanning electron microscopy (SEM). Generally the dermis is highly vascularized by two capillary networks, which are localized beneath the epithelium and beneath the dermal papillas. The dense subepithelial network is characterized by the presence of sinusoid vessels. In the subcutaneous plexus numerous arteriovenous anastomoses of different types occur. Additionally there are arteriovenous anastomoses between the main vessels reaching the indentations of the comb. Our results show the presence of superficial and dense capillary networks and arteriovenous anastomoses are the anatomical basis for the functions of the chicken comb in mating behaviour and thermoregulation. Reference, Schummer, A. 1951: Simplified method for plastoid corrosion. Anat. Anaz. 98, 288,290. [source] | |||||||||||||