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At least 19 recordsLinked to original sources
PubMedDate not supplied

[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.

Aorta, Thoracic↗
PubMed2001

[The thickness change and clinical significance of tunica intima and smooth muscle in artery after hydrolic dilation].

OBJECTIVE: To study the proliferation change of tunica intima and smooth muscle in artery after hydrolic dilation for potential clinical use. METHODS: Sixten adult New Zealand rabbits were randomly divided into 4 groups, named group A, B, C and D. Right carotid arteries of rabbits of those 4 groups were dilated by hydrolic dilation with different pressures with 0 kPa, 40 kPa, 80 kPa, and 120 kPa respectively. The arterial calibers, thickness of tunica intima and smooth muscle were analyzed by automatic medical photograph analyzer immediately, 1 week and 2 weeks later respectively. RESULTS: The arterial calibers in the experimental group were larger than those in control group after immediate hydrolic dilation and 1 week later (P < 0.01). At 2 weeks, the arterial calibers in group B and D has no significant difference compared to group A (P > 0.05), and those in group C were larger than that of group A (P < 0.01). There were no significant difference in thickness of tunica intima and smooth muscle between the experimental group and control group (P > 0.05) after immediate hydrolic dilation. At 1 and 2 weeks after dilation, there were no significant difference between group A and group B (P > 0.05), and those in group C and D were all larger than those in group A (P < 0.01). No obvious proliferation of tunica intima were observed in group B at 2 weeks after hydrolic dialation, but the proliferation of tunica intima could be observed in group C and D, especially in group D. CONCLUSION: Caliber of artery can be expanded by hydrolic dilation with higher pressure, but the proliferation of tunica intima and smooth muscle may be occurred in hydrolic dilation with higher pressure over 80 kPa, therefore it is safe to use hydrolic dilation with pressure no more than 40 kPa.

Animals↗
PubMed2000

Structural changes in the tunica intima of varicose veins: a histopathological and ultrastructural study.

Many factors have been implicated in the aetiology of varicose veins; however, there is ample evidence implicating that the defect is in the wall of the lower limb veins. In order to know the pathological changes in the tunica intima of varicose veins, the smooth muscle cells (SMCs), collagen and elastin of varicose and control patients were studied by light and electron microscopy. The morphological changes in the SMCs, collagen and elastin point to a possible secretory or phagocytic role of the SMCs in producing abnormal immature collagen or elastin fibres or in modulation of function of SMCs due to excessive production of extracellular matrix (ECM).

Adult↗
PubMed1992

[Protection of the tunica intima during preservation of venous bypass grafts from harvesting to implantation].

The patency-rate of venous bypasses depends--beside other important factors--upon the integrity of the transplanted vessel, especially on the condition of the tunica intima. We investigated two different methods of venous storage and their on the intima. We examined 24 segments of healthy human saphenous vein and 65 segments of the inferior vena cava in the rat which had been harvested using a minimal touch technique. The veins were stored in the patients own arterial heparinized blood vs. Euro Collins solution at 4 degrees C, 20 degrees C and 37 degrees C over 15, 30, 60, and 90 minutes. As a reference we examined 11 segments of human saphenous vein which had been fixed immediately after harvesting. The stainings were performed with PAS, HE, Domagk-Elastica, and Toluidine-blue. We examined 1,181 slices by light-microscopy and used a damage score table for the documentation of the vein-trauma. No significant differences were found between human and animals veins. In the control-group the endothelium, the subendothelial layer, and the intern elastic membrane were intact in 57%, 78%, and 38%. At 4 degrees C the endothelium was intact in 31% having been stored in blood, and in 44% at Euro Collins solution. For the subendothelial layer the ratio was 48%/66%, and for the intern elastic membrane 26%/42%. At 20 degrees C we found a ratio of 55%/47% vs. 65%/58% vs. 37%/39%, and at 37 degrees C 56%/37% vs. 64%/51%/32%/38%. The factor time could be neglected up to 90 minutes. The results show that veins should be used immediately after harvesting.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[A comparative ultrastructural and morphometric analysis of the smooth myocytes in the tunicae intima and media of the human fetal aorta].

Transmission electron microscopy was used for studying the thoracic part of the aorta of 9 human fetuses of 20-28 weeks of development. In the medial tunic of the human fetus aorta there are smooth myocytes (SM) of the contractile and synthetic phenotypes. The latter are localized mainly in the inner part of the media. In the inner tunic there are also SM of the synthetic phenotype. With the help of processes they make contacts with endotheliocytes and processes of SM of the media. In the gaps between the subendothelial SM and endothelium there are particles of elastin which form the structure resembling an additional elastic membrane. It is reasonable to think that the migration of SM into the intima is a stage of normal development of the vessel associated with the adaptation to local hemodynamic conditions rather than an initial manifestation of atherosclerosis.

Aorta, Thoracic↗
PubMed1994

Changes in morphology of elastin fibers during development of the tunica intima of monkey aorta.

The normal development of elastin fibers in the thoracic aorta was studied in fetal, young, and adult monkeys. Tissue was examined by scanning electron microscopy (SEM) after NaOH treatment and by transmission electron microscopy (TEM). The NaOH treatment of fixed tissues effectively removed collagen fibers and enabled three-dimensional visualization of the elastin fibers. In intact fetal aortae, the internal elastic lamina (IEL) was situated immediately beneath the endothelium. This IEL consisted of superficial, longitudinally arranged bundles of elastin fibrils and an underlying solid sheet containing round fenestrations. In neonates, diffuse intimal thickening was observed. In the young and young-adult monkeys, the aortae exhibited intimal thickening with slender but split IEL. One of the most important findings of this study was that elastin fibers in the intimal thickening, as well as smooth muscle cells, ran in a longitudinal fashion. This was in contrast with the elastic laminae of the media which were mainly oriented circumferentially. Subendothelial elastin fibers in this intimal thickening combined with longitudinally arranged microfibrils which formed close associations with endothelial stress fibers. In some adult monkey aortae with well-developed intimal thickening, a complex meshwork of slender elastin fibers was also found beneath the endothelium. The development of the intimal elastin fibers is discussed in relation to hemodynamic forces.

Actin Cytoskeleton↗
PubMed2001

A histological study on the coronary artery of the indigenous black Bengal goat in Bangladesh.

The coronary artery of the black Bengal goat was studied by light microscopy. The wall of the coronary artery consisted of the tunica intima, tunica media and tunica externa. The tunica intima consisted of a single layer of flattened endothelium. The tunica media was well-developed and composed of mainly of smooth muscle cells together with some fine elastic fibers. The tunica externa consisted of predominant collagen fibers, and some elastic fibers and smooth muscle cells. Elastic fibers in the tunica externa formed a circular arrangement around the tunica media. Sex differences were not observed. The media with well-developed smooth muscle cells may be responsible for changes in functional physiological conditions of the heart.

Animals↗
PubMed1998

The differential distribution of hyaluronic acid in the layers of human atheromatic aortas is associated with vascular smooth muscle cell proliferation and migration.

Vascular smooth muscle cells (VSMC), under conditions of induced proliferation, similar to those involved in atherosclerosis, secrete an acidic glycan, 82% of which exhibits structural homology with hyaluronic acid (HA), has a molecular mass of 340 kDa (HA-340) and inhibits VSMC proliferation in vitro. In this study, the expression of glycans was investigated in human atheromatic aortas and evidence is presented that a HA molecule, similar to HA-340, is distinctly expressed in all aortic layers. The isolation of the glycans from human aortas was performed after homogenization of the individual aortic layers (atheromatic plaque, tunica intima, tunica media and tunica adventitia), by lipid extraction and extensive digestion with pronase and DNase. The total glycans were purified from the digestion products by gel filtration on Sephadex G-25 and fractionated on a Superose 6 column. Enzymatic treatment of the ensuing glycan fractions with all known glycosaminoglycan-degrading enzymes, followed by electrophoresis on polyacrylamide gradient gels and cellulose acetate membranes, revealed that, in addition to HA, the tunica intima and the atheromatic plaque also contained dermatan sulfate, while the tunica media and the tunica adventitia also contained chondroitin sulfates and heparan sulfate. The highest concentration of the human aorta HA was found in the tunica media, exhibiting a negative concentration gradient from the tunica media to the atheromatic plaque. Investigation of the biological function of the human aorta HA revealed that this molecule acts as a negative regulator on the PDGF-induced VSMC proliferation and as a positive regulator on the PDGF-induced VSMC migration. The differential expression of HA within the aortic layers correlates with the biological function attributed to this acidic glycan and associates it with key events in the progression of atherogenesis.

Adult↗
PubMed2006

[Inhibitory effect of irbesartan on restenosis after balloon angioplasty and mechanism thereof: experiment with rabbits].

OBJECTIVE: To investigate the inhibitory effect of irbesartan on the restenosis after balloon angioplasty and mechanism thereof. METHODS: Forty-eight Harbin white rabbits underwent balloon angioplasty at the left common carotid artery to establish models of restenosis (RS) and then were randomly divided into 3 groups of 8 rabbits: 7 d, 14 d, and 28 d to be fed with the diet with 35 mg/kg irbesartan till the day when the rabbits were to be killed, each group with 4 controls fed with normal diet At the scheduled days the rabbits were killed and their left common carotid arteries, livers, and kidneys were taken out to undergo morphological examination. The areas of the tunica intima, tunica media, and lumen of the common carotid artery were measured. Immunohistochemistry was used to detect the nuclear factor-kappaB p65 (NF-kappaB p65) and proliferating cell nuclear antigen (PCNA) protein. RT-PCR was used to detect the mRNA expression of inhibitor-kappaB (I-kappaB) and monocyte chemoattractant protein-1 (MCP-1). RESULTS: No abnormality was found in the specimens of liver and kidney. Measurement showed that the area of tunica intima of the 7 d irbesartan group was 0.34 mm(2) +/- 0.15 mm(2), significantly smaller than that of the controls (1.05 mm(2) +/- 0.38 mm(2), P < 0.05), and the area of arterial lumen of the 28 d group was 4.25 mm(2) +/- 0.29 mm(2), significantly larger than that of the controls (2.56 mm(2) +/- 1.02 mm(2), P < 0.05). Immunohistochemistry showed that the rates of NF-kappaB p65 positive cell and PCNA positive cell of the 7 d irbesartan group were both significantly lower than those of the controls (both P < 0.05). The mRNA expression of I-kappaB in the vascular wall of the 7 d irbesartan group was significantly lower than that of the controls. The mRNA expression levels of MCP-1 at different time points were all significantly lower than those of the corresponding controls (all P < 0.05). CONCLUSION: Irbesartan inhibits the RS after injury of arterial wall by balloon angioplasty via suppressing the activation of NF-kappaB p65 which controls the expression of I-kappaB and MCP-1.

Animals↗
PubMed1984

Histologic examination of selected areas of canine pulmonary arteries.

Selected areas of pulmonary arteries from 18 healthy mixed-breed dogs were examined using histologic staining techniques. Smooth muscle cell, collagen, and elastin content of the tunica intima and tunica media were assessed. Fifteen dogs had abnormalities of tunica intima or tunica media in at least one arterial section examined. Of all arterial sections examined, 40% had histologic changes of the tunica intima or tunica media, and 42% of these vascular lesions were in the main pulmonary artery. The most commonly occurring pathologic change was loss of smooth muscle cells and elastin of the tunica media and replacement by collagen. This lesion is similar to cystic medionecrosis of the aorta. Seemingly, a high frequency of spontaneous vascular lesions exist in pulmonary arteries of young dogs.

Animals↗
PubMed1990

The aortic wall: an in vitro study of the double-line pattern in high-resolution US.

An in vitro study of macroscopically normal aortas from human cadavers was performed with high-resolution ultrasound (US). Rectangular pieces of 10 fresh aortas were submerged in saline solution and scanned from the intimal side. On US images a characteristic double-line pattern, consisting of an inner and an outer echogenic line separated by a relatively hypoechoic line, was seen. This configuration was initially interpreted as tunica intima, tunica media, and tunica adventitia. The thickness of each layer on the US images was measured by means of a computer-assisted procedure and on histologic specimens was measured by means of stereomicroscopy. The correlation between the two measurements was poor. Experiments in which intima and part of the media were removed did not change the US appearance. Plexiglas, metal plates, and plastic foil showed a similar double-line pattern. A needle experiment disclosed that the inner echogenic and the hypoechoic lines were displayed in front of the true water-tissue interface, which was represented by the outer echogenic line. The authors conclude that the double-line pattern is thus an artifact.

Aorta↗
PubMed1990

Histopathology of microarterial anastomoses: end-to-end versus end-in-end (sleeve) technique.

The healing process of microarterial anastomoses after two different techniques is described after an evaluation of 80 rabbit arterial anastomoses. The two techniques used were as follows: group I, conventional end-to-end technique; and group II, end-in-end (sleeve) technique. After operation the anastomoses were checked at 1 hour, 24 hours, 3 days, 7 days, 2 weeks, 6 weeks, 3 months, and 6 months. The changes occurring at the tunica intima, tunica media, and adventitia were histologically evaluated and morphometric measurements were taken at the anastomotic site. Histologic evaluation of both techniques showed that the rabbits treated with the sleeve technique healed faster with less endothelial damage. The sleeve technique presented a different healing pattern but comparable long-term patency rates with the conventional end-to-end anastomosis technique.

Anastomosis, Surgical↗