Tunica Media (tunica + media)

Distribution by Scientific Domains

Selected Abstracts

Immediate Pathologic Effects on the Vein Wall of Foam Sclerotherapy

BACKGROUND During the past 10 years, sclerotherapy has radically changed, the foam sclerotherapy method being better than that of liquid sclerotherapy. OBJECTIVES We have analyzed the immediate pathologic effects on the saphenous vein wall in vivo after sclerotherapy with sodium tetradecyl sulfate (STD) foam. METHODS A group of six patients affected by chronic venous insufficiency, operated on by stripping of the saphenous vein, underwent an intraoperative procedure of sclerotherapy to an isolated but not yet removed tract of saphenous vein with 3% STD foam. RESULTS The pathologic damage of the foam was extremely rapid with complete damage of the endothelium within the first 2 minutes. In the successive 15 and 30 minutes there was edema of the intimal with its progressive separation from the tunica media and the initial formation and adhesion of the thrombus to the tunica media. CONCLUSIONS In this in vivo report we analyze the capacity of 3% STD foam sclerotherapy to damage the saphenous vein wall. The damage is extremely fast and shows the detachment of the intimal and the development of the microthrombus. [source]

Pathology of lethal peripartum broad ligament haematoma in 31 Thoroughbred mares

Summary Reasons for performing study: Broad ligament haemorrhage in peripartum mares is a life-threatening disease and there are few reports on the aetiology and pathogenesis of broad ligament haematoma. Objectives: To obtain information regarding the sites for the early diagnosis and pathogenesis of broad ligament haematoma of mares. Methods: Thirty-one mares that died of broad ligament haematoma peripartum were examined pathologically for bleeding sites. The arterial distribution of 5 young mares with several parities served as negative controls. Results: Age and/or multiparity were the predisposing factors for the disease. Arterial injuries were most commonly observed in the uterine artery (24 of 31 mares). Among these, the proximal uterine artery that lies within 15 cm of the bifurcation of the iliac artery was the most frequent site for rupture (18 mares). The lesions occurred preferentially at the bifurcations, lateral part of curvatures and abrupt flexures of the artery. The morphology of the injuries was classified into 3 types: ruptures with and without longitudinal fissures, and transections. Histologically, the arterial wall adjacent to the rupture showed atrophy of smooth muscle cells with fibrosis of the tunica media and disruption and/or calcification of the internal elastic lamina. Conclusions: Arterial injuries that led to broad ligament haematoma in peripartum mares occurred most frequently in the proximal uterine artery, and atrophy of smooth muscle cells with fibrosis of the arterial wall was as one of the predisposing factors in aged and multiparous mares. Potential relevance: Monitoring small aneurysms, mural tearing, medial fibrosis at the proximal uterine artery by transrectal echography could provide useful information for the early diagnosis and possible prevention of broad ligament haematoma of peripartum mares. [source]

Angioleiomyoma: a clinical, pathological and radiological review

P. Ramesh
Summary Angioleiomyoma is a benign tumour arising from the vascular smooth muscle (tunica media) and presents commonly between third and fifth decades of life. Although there are sporadic reports about this tumour in the literature, none describes all the information in detail. This review is an attempt to collate all the facts in one concise article. Angioleiomyoma presents as a painful mass in approximately 60% of the cases. One of the distinct clinical feature noted is the increase in size of the swelling with physical activity of the involved part, especially in the hand. It should be considered in the differential diagnosis of painful nodular lesions of the extremity. Pre-operative diagnosis is difficult, but with a high index of suspicion and awareness, it is possible. The use of ultrasound and magnetic resonance imaging should be considered. It causes minimal morbidity and excision is usually curative. Histological examination using smooth muscle Actin stain portraits the smooth muscle bundles clearly. [source]

Close relation of arterial ICC-like cells to the contractile phenotype of vascular smooth muscle cell

Vladimír Pucovský
Abstract This work aimed to establish the lineage of cells similar to the interstitial cells of Cajal (ICC), the arterial ICC-like (AIL) cells, which have recently been described in resistance arteries, and to study their location in the artery wall. Segments of guinea-pig mesenteric arteries and single AIL cells freshly isolated from them were used. Confocal imaging of immunostained cells or segments and electron microscopy of artery segments were used to test for the presence and cellular localization of selected markers, and to localize AIL cells in intact artery segments. AIL cells were negative for PGP9.5, a neural marker, and for von Willebrand factor (vWF), an endothelial cell marker. They were positive for smooth muscle ,-actin and smooth muscle myosin heavy chain (SM-MHC), but expressed only a small amount of smoothelin, a marker of contractile smooth muscle cells (SMC), and of myosin light chain kinase (MLCK), a critical enzyme in the regulation of smooth muscle contraction. Cell isolation in the presence of latrunculin B, an actin polymerization inhibitor, did not cause the disappearance of AIL cells from cell suspension. The fluorescence of basal lamina protein collagen IV was comparable between the AIL cells and the vascular SMCs and the fluorescence of laminin was higher in AIL cells compared to vascular SMCs. Moreover, cells with thin processes were found in the tunica media of small resistance arteries using transmis-sion electron microscopy. The results suggest that AIL cells are immature or phenotypically modulated vascular SMCs constitutively present in resistance arteries. [source]

Renal cortex remodeling in nitric oxide deficient rats treated with enalapril

Noemi Barbuto
Abstract The kidney NO synthase is one of the most important renal controlling systems. This paper aims the quantification of renal cortical components involved in blood pressure regulation under NOs blockade. Spontaneous hypertensive rats (SHRs) are submitted to chronic blockade of NOs by L-nitro-arginine-methyl-ester (L-NAME) and an ACE inhibitor (enalapril) in comparison with the normotensive Wistar rats. Twenty SHRs and 5 Wistar rats were divided in 5 groups and observed for 21 days for blood pressure (BP) and serum creatinine: control Wistar (5) (C-W), control SHR (5) (C-SHR), L-SHR (5) - received L-NAME 30 mg/kg/day, L+E-SHR (5) - received L-NAME and Enalapril maleate 15 mg/kg/day, E-SHR (5) - received Enalapril maleate. A quantitative morphometric study (glomerular density, QA[g1], interstitium volume density, Vv[i], tubular surface and length densities, Sv[t] and Lv[t]) were performed at the end. The BP reached 226±15 mmHg in L-SHR group. The BP difference between the L-SHR and the C-SHR groups was significant from the first week while the E-SHR group became significant from the second week. At the end of the experiment the BP of the E-SHR group was similar to the BP in the C-W group. The QA[g1] was similar among C-SHR, L-SHR and L+E-SHR groups and no difference was found between E-SHR and C-W groups. In the L-SHRs serum creatinine was greatly increased, and microscopy showed thickening of arteriolar tunica media with an increase of the wall-to-lumen ratio, perivascular fibrosis, inflammatory infiltrated, tubular atrophy and interstitial fibrosis with focal segmental glomerulosclerosis. The use of enalapril was not completely efficient in reducing BP and morphological injury when the hypertension of SHRs was increased with the NOs blockade suggesting that NO deficiency-induced hypertension is not entirely mediated by the RAAS. [source]

FRNK, the autonomously expressed C-terminal region of focal adhesion kinase, is uniquely regulated in vascular smooth muscle: Analysis of expression in transgenic mice

Haruko Hayasaka
Abstract FRNK, the autonomously expressed carboxyl-terminal region of focal adhesion kinase (FAK), is expressed in tissues that are rich in vascular smooth muscle cells (VSMCs). Here we report the generation of transgenic mice harboring the putative FRNK promoter fused to LacZ and examine the promoter activity in situ via expression of ,-galactosidase. The transgenic mice exhibited expression of ,-galactosidase predominantly in arterial VSMCs in large and small blood vessels of major organs. Upregulation of ,-galactosidase activity was observed in tunica media following carotid injury, indicating that the FRNK promoter is activated in VSMCs in response to injury. Robust expression of ,-galactosidase in blood vessels was also detected in the developing embryo. However, expression was also observed in the midline, the nose and skin epidermis, indicating distinct transcriptional regulation of the FRNK promoter in embryogenesis. To analyze FRNK expression in vitro, we identified a 116 bp sequence in the FRNK promoter that was sufficient to function as an enhancer when fused to the minimal actin promoter and expressed in cultured smooth muscle cells. Mutation of AP-1 and NF-E2 binding consensus sequences within this element abrogated enhancer activity, supporting the involvement of this promoter element in VSMC expression of FRNK. © 2005 Wiley-Liss, Inc. [source]

Development of the avian lymphatic system,

Jörg Wilting
Abstract Recently, highly specific markers of the lymphatic endothelium have been found enabling us to reinvestigate the embryonic origin of the lymphatics. Here we present a review of our studies on the development of the lymphatic system in chick and quail embryos. We show that the lymphatic endothelium is derived from two sources: the embryonic lymph sacs and mesenchymal lymphangioblasts. Proliferation studies reveal a BrdU-labeling index of 11.5% of lymph sac endothelial cells by day 6.25, which drops to 3.5% by day 7. Lymphangioblasts are able to integrate into the lining of lymph sacs. Lymphatic endothelial cells express the vascular endothelial growth factor (VEGF) receptors-2 and -3. Their ligand, VEGF-C, is expressed almost ubiquitously in embryonic and fetal tissues. Elevated expression levels are found in the tunica media of large blood vessels, which usually serve as major routes for growing lymphatics. The homeobox gene, Prox1, is expressed in lymphatic but not in blood vascular endothelial cells throughout all stages examined, namely, in developing lymph sacs of day 6 embryos and in lymphatics at day 16. Experimental studies show the existence of lymphangioblasts in the mesoderm, a considerable time before the development of the lymph sacs. Lymphangioblasts migrate from the somites into the somatopleure and contribute to the lymphatics of the limbs. Our studies indicate that these lymphangioblasts already express Prox1. Microsc. Res. Tech. 55:81,91, 2001. © 2001 Wiley-Liss, Inc. [source]

Histological Assessment of Selected Blood Vessels of the Phocid Seals (Northern Elephant and Harbour Seals)

H. Smodlaka
Summary Phocid seals exhibit vascular adaptations that allow them to undertake prolonged deep dives. These vascular adaptations are either unique to phocids, or are modified vascular equivalents to those present in terrestrial mammals. One such adaptation, the aortic bulb, is a spherical enlargement of the ascending aorta specific to phocid seals. Its histological make-up consists of a reinforced tunica media with circular and longitudinal layers of elastic fibres. This reinforcement enables multi-axial deformation of the aortic bulb, thus complementing its function as a prominent elastic reservoir or ,windkessel'. A second adaptation, the hepatic sinus, is an asymmetrical dilation of the abdominal portion of the caudal vena cava and accompanying hepatic veins. The hepatic sinus is comprised of a relatively thin tunica media, with a scant smooth muscle component. The bulk of the sinus wall is comprised of tunica adventitia. A third vascular adaptation distinctive to the phocids is the pericardial venous plexus, composed of convoluted veins circumnavigating the perimeter of the heart. Microscopically, these veins have a thick tunica media and also contain valves. Smaller arteries, venules and distinct capillary beds are observed interspersed in-between these veins. It can be hypothesized, that in seals, certain vascular embryonic development may be arrested at an earlier embryonic stage, resulting in these unusual vascular formations. These modifications play a vital role in blood pressure regulation and distribution of oxygenated blood during prolonged deep diving. The purpose of this work was to elucidate the histological aspects of these unique vascular modifications and relate them to specific function. [source]

The Immunohistochemical Localization of Desmin and Smooth Muscle Actin in the Ovary of the African Giant Rat (Cricetomys gambianus) During the Oestrous Cycle

M.-C. Madekurozwa
Summary The aim of this study was to describe the distribution of smooth muscle actin and desmin immunopositive cells in the ovary of the giant rat. In addition, the study describes the morphological changes in the ovary of this species during the oestrous cycle. Healthy secondary and tertiary follicles dominated the ovary during pro-oestrus and oestrus. The theca externa of the tertiary follicles was immunopositive for smooth muscle actin, but immunonegative for desmin. Oestrus was also characterized by the presence of corpora haemorrhagica, which had an outer layer of smooth muscle actin immunopositive cells. Differentiating corpora lutea were observed during metoestrus. A further notable feature of the ovary during metoestrus was the presence of numerous atretic secondary and tertiary follicles. In the later stages of atresia, the follicles were infiltrated by desmin and smooth muscle actin immunopositive cells. Dioestrus was characterized by the presence of non-regressing and regressing corpora lutea. Immunostaining for smooth muscle actin was demonstrated in the enclosing layer of the corpora lutea, as well as in the tunica media of blood vessels within the corpora lutea. The results of this study have shown that morphological changes in the ovary of the giant rat during the oestrus cycle are similar to those of laboratory rodents. Furthermore, the results of the immunohistochemical study indicate that the perifollicular distribution of desmin and smooth muscle actin cells changes during follicular development and atresia. [source]

Structural Differences in the Umbilical Vein Wall after Full-Term and Pre-term Delivery

M. Bagyánszki
Summary With the exception of its most proximal segment, the human umbilical cord lacks innervation. It might be expected, therefore, that a paracrine effect through the direct contact between the smooth muscle cells and the endothelium may be particularly important in the control of the fetoplacental circulation. In this study, electron microscopy and immunohistochemistry were applied to examine umbilical veins immediately after full-term and pre-term delivery. The smooth muscle cells in the upper layer of the tunica media exhibited long, foot-like processes with c-kit immunoreactivity. In the umbilical vein of full-term neonates more than 50% of these cell processes display a normal ultrastructure and they were closely associated with the lamina elastica interna. Whereas in pre-term infants more than 60% of these cell processes exhibit signs of severe shrinkage and detachedness from the lamina elastica interna. At the same time, the high level of immunoreactivity of the endothelial cells as regards the proapoptotic gene product Bax in pre-term infants is indicative of an enhanced apoptotic process in these cells. [source]

Vanadyl sulfate protects against streptozotocin-induced morphological and biochemical changes in rat aorta

Kadriye Akgün-Dar
Abstract The aim of this study was to investigate the protective effects of vanadyl sulfate on aorta tissue of normal and streptozotocin (STZ)-induced diabetic rats, morphologically and biochemically. The animals were made diabetic by an intraperitoneal injection of streptozotocin (65,mg/kg) and vanadyl sulfate (100,mg/kg) that was given every day for 60 days by gavage technique to rats. Under the light and transmission electron microscopes, hypertrophy of the vessel wall, focal disruption in the elastic lamellae, an increase in thickness of total aortic wall, tunica intima, subendothelial space and adventitial layer, and a disorganization in smooth muscular cells of the tunica media were observed in diabetic animals. The aorta lipid peroxidation (LPO) levels were significantly increased and the aorta glutathione (GSH) levels were significantly reduced in STZ diabetic rats. In diabetic rats administered vanadyl sulfate for 60 days, aorta LPO levels significantly decreased and the aorta GSH level significantly increased. In conclusion, in vivo treatment with vanadyl sulfate of diabetic rats prevented the morphological and biochemical changes observed in thoracic aorta of diabetic animals. Copyright © 2006 John Wiley & Sons, Ltd. [source]