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PubMedDate not supplied

[Relationship between arterial pressure evolution and free hemoglobin distribution into vascular wall in guinea pigs].

Free hemoglobin (Hb) present at high concentration in plasma--in case of hemolysis, hemoglobin based oxygen carrier (HBOC) administration or in case of subarachnoid hemorrhage--induce hypertension as result of vasoconstriction. In this context, we studied on an exchange transfusion (ET) model at 50% of hematocrit with a HBOC, the distribution of this Hb inside abdominal aortic wall in guinea pigs in relation with mean arterial pressure (MAP) evolution. MAP was monitored during 180 min after ET and rings of abdominal aorta were taken at different times, when modifications of MAP were important, and analyzed by immunohistochemistry and confocal microscopy. Gelofusine 4%, used as control, did not modify MAP while free Hb increased MAP that reached its maximum (53% of hypertension) at t=17 min after the end of ET. MAP started to decrease (45% of hypertension) at t =60 min after ET, and recovered its baseline value at t=180 min. Confocal analysis of the vessel showed that: at 17 min (when hypertension was maximal), free Hb was present in endothelial cells (EC) and in vasa vasorum; at t=60 min (when hypertension decreased) and at t =10 min (when hypertension disappeared), free Hb was detected still in EC, but inside all abdominal aorta wall too. These results suggest in the first time that free Hb could induce a hypertension by direct interaction with EC but would also be unable to maintain this hypertension in spite of its massive tissue distribution.

Animals↗
PubMed2005

Coupled oxygen transport analysis in the avascular wall of a post-angioplasty coronary artery stenosis.

The coupled oxygen transport in the avascular wall of a coronary artery stenosis is studied by numerically solving the convection-diffusion equations. Geometry, replicating residual stenosis after percutaneous transluminal coronary angioplasty (PTCA), is used for the analysis. Important physiological aspects, such as oxygen consumption in the wall, oxygen carried by the hemoglobin, non-Newtonian viscosity of the blood, and supply of oxygen from the vasa vasorum are included. Mean blood flow rate in the lumen is varied from basal to hyperemic conditions. The results show that the P(O2) in the medial region of the arterial wall is approximately 10 mmHg. The oxygen flux to the wall increases in the flow acceleration region, whereas it decreases at the flow reattachment zone. Near the location of flow separation there is a small rise and a sharp fall in the oxygen flux. The minimum P(O2) in the avascular wall, P(O2, min ), at the point of flow reattachment reduces to approximately 6 mmHg for a 300 micron wall thickness. For a thinner wall of 200 micron, the P(O2, min ) at the location of flow reattachment increases to 6 times that of a 300 micron wall. The P(O2, min ) in the wall decreases by 60% when volumetric oxygen consumption is increased by 30% for the same avascular wall thickness.

Angioplasty, Balloon, Coronary↗
PubMed2003

Morphology of umbilical vessels in human fetuses: a quantitative light microscope study.

OBJECTIVE: To investigate the development of the intra-abdominal part of the umbilical vessels in human fetuses by light microscopy. MATERIALS AND METHODS: The location of the umbilicus and umbilical vessels in the abdominal cavity of 90 human fetuses of gestational ages 10-40 weeks was determined. The external vessel diameter, lumen diameter, wall thickness, tunica adventitia thickness, tunica media thickness and the number of vasa vasorum were recorded from cross-sectlons of the intra-abdominal part of the umbilical vessels. 1985). 1985). RESULTS: Umbilical artery agenesis was observed on the left side in two cases and on the right in one case. There was a positive correlation between gestational age and umbilical vessel measurements. There were differences between the vessel and lumen diameters, tunica media thicknesses of the vessels of the second and third trimesters, and the full-term period. There were also predictable differences between the vessel and lumen diameters, tunica media and tunica adventitia thicknesses of the umbilical vein and umbilical arteries. CONCLUSION: Detailed information on quantitative parameters of umbilical vessels at each gestational age may prove helpful in determining pathologies of umbilical vessels and illuminating certain syndromes.

Adult↗
PubMedDate not supplied

[Coronary aneurysms not associated to stenosis of coronary arteries. Conservative treatment and evolution in six patients].

Coronary artery aneurysms are a relatively infrequent finding with an incidence of 1-2% per year. The most frequent cause is atherosclerosis and, in that case, they are always associated to stenosis of coronary arteries. We reviewed the coronary angiographic studies performed in the past seven years and we identified six patients that were admitted with an acute coronary syndrome, whose angiographic studies showed the presence of aneurysms in, at least, one of the coronary arteries. In these patients, we found no relation between aneurysms and distal or proximal stenosis. Although there was no angiographic evidence of classical coronary atherosclerosis, we think that atherosclerotic disease could have been the etiological cause, due to injury of the endothelium and media by deposits of lipids, smooth muscle cells, collagen, macrophages, and T-lymphocytes that would have damaged the adventitia layers of the vessel wall, stimulating "vasa-vasorum" neovascularization. The evolution of coronary aneurysms without associated stenosis in the same coronary artery and without another potentially treatable cause is unknown. Due to the limited literature regarding this issue and, taking into account our experience, we feel that, in these cases, medical treatment might be a good option as we detected no major cardiac events in any patient at mid and long-term follow up.

Aged↗
PubMed2006

Stereological study of neovascularization in temporal arteritis.

OBJECTIVE: As giant cell arteritis (GCA) progresses, newly formed microvessels are one of the main sites of leukocyte-endothelial cell interaction. Our aim was to stereologically map the distribution of microvessels in the temporal arterial wall and to assess their relationship to the degree of inflammation in GCA. METHODS: Inflamed temporal arteries from 21 patients who fulfilled the American College of Rheumatology criteria for GCA were analyzed. Paraffin sections, stained with an antibody directed at vascular endothelium, were analyzed stereologically. The degree of inflammation and the surface of microvascular endothelium per volume (microm2/microm3) were assessed in 4 different layers of the arterial wall. RESULTS: The degree of inflammation and of vascularization was greatest in the adventitia, smaller in the media, and smallest in the intima. A significant positive relationship was observed between the degree of inflammation and the degree of vascularization in the media and in the outer and inner layers of the intima. In 8 biopsies, the microvessels formed a prominent plexus in the intima without apparent connection with microvessels in the adventitia/media, and there were no signs of endothelial budding from the arterial lumen. CONCLUSION: Our results confirm that inflammation is a major determinant in neovascularization in GCA. Some new microvessels are formed by the budding of the adventitial vasa vasorum. The presence of intimal microvascular networks without apparent connection with microvessels in the media might indicate additional influence on neovascularization.

Aged↗
PubMed1992

Ultrastructural localization of endogenous albumin in human aortic tissue by protein A-gold immunocytochemistry.

The presence of endogenous plasma albumin in human aortas was demonstrated by immunocytochemical procedures. The protein A-gold approach, combining high resolution and specificity, was applied at the light and electron microscope levels to determine the in situ cellular and extracellular localization of albumin on tissue sections derived from normal and atherosclerotic human aortas. The distribution of albumin across the aortic wall interstitium was found to be uneven, with low to moderate staining intensities in the aortic subendothelial space, low intensities in the media, and high intensities around the vasa vasorum in the adventitia. Albumin was associated with collagen fibers as well as with the electron-dense material bordering the elastic laminae in both normal and pathologic tissues. Extracellular multilamellar structures were found to be characteristic of the necrotic areas of atherosclerotic aortas. These structures were intensely labeled for albumin, with the labeling being closely associated with the membranes. Numerous smooth muscle cell-derived and monocyte-derived foam cells were present in pathologic tissues, and some of their lysosomal compartments were labeled for albumin, suggesting an internalization and degradation of interstitial albumin by these cells.

Aged↗
PubMedDate not supplied

[Diagnosis of deep venous thrombosis of the lower limbs by computed tomography].

In the CT scan of a patient with knee tumor and deep vein thrombosis confirmed by phlebography, the casual observation of a thrombus image in the vein was made, characterized by wall contrastation in opposition to a lack of luminar contrastation. Then, CT scans of the lower limbs and the pelvic region were performed in 14 patients with suspected DVT, who were followed consecutively. Diagnosis of ruptured Baker cyst was made in one patient and DVT in 13 patients. DVT was demonstrated in both lower limbs of three patients. Diagnosis of DVT was confirmed in six of seven exams involving the legs. CT scan could detect thrombi in muscular veins and in deep femoral and internal iliac veins. In six patients with suspected pulmonary embolism, CT scan was also made of the thoracic region and showed pleuropulmonary involvement concomitant with lower limb DVT. The characteristic image of DVT in CT is that of a contrasted ring. Its brightness may be due to contrastation of the venous wall through its vasa vasorum, whereas the thrombus obstructs the luminar flow of the contrast medium. Reproducibility of the characteristic image of thrombus presence in the vein at different levels of the lower limbs and pelvic region gives CT the status of alternative diagnosis means for DVT. False negatives and false positives should be evaluated.

Adult↗
PubMedDate not supplied

[Femoro-popliteal bypass in situ].

The authors present early and late results of femoro-popliteal/crural reconstruction where "in situ" technic is used. Of 35 patients 10 had the third stage of occlusive disease by Fontain, and 25 were in the fourth stage. Therefore the reconstruction consisted of "limb salvage procedure". The aim of the study was to present the possibilities of this technique in cases with ischaemic extremities and poor "run off". The early potency of prosthesis within the first month was 97% (34 patients) and late (after one year) 91% (32 patients). In three patients, in early postoperative stage, AV fistulas were found and successfully surgically treated. AV fistulas were caused by non-ligated branches of the saphenous vein. Thus, a conclusion was drawn that intraoperative control angiography vas of great importance. Better potency of prosthesis, when compared to the quality of saphenous vein graft and when used "in situ", over the classical method was achieved thanks to the following facts: no damage of the intima caused by hydrostatic dilatation; possible use of a vein whose diameter is less than 4 mm; no damage of adventitia (vasa vasorum) due to the slower degenerative process of the vein wall; impossible graft torsion; low compliance level between the graft and the small artery, and small artery caused by the conic shape of graft.

Female↗
PubMed1991

Primary coronary artery dissection possibly related to drug hypersensitivity in a male.

Primary coronary artery dissection is rare, usually affects females (greater than 85%), and has most often affected the left anterior descending coronary artery. The authors report a case that is unusual in four respects: the patient was male, the involved artery was a marginal branch of the circumflex, the resulting small infarct ruptured, and most importantly, the patient had recently experienced a drug hypersensitivity reaction. The microscopic finding of a heavy eosinophil and mast cell infiltrate around the dissected artery may indicate that dissection occurred as a result of hypersensitivity angiitis of the vasa vasorum, as has previously been suggested in the literature.

Aortic Dissection↗
PubMed1990

Comparative anatomy of the tracheobronchial circulation.

This review considers the similarities and difference between several animal species to determine which are most appropriate for studies of the human bronchial circulation in health and disease. The subgross anatomy of the sheep, cow, pig and horse appear to be similar to that of humans. These species have a major bronchial artery with a consistent location. In humans and other species, there is evidence of anastomoses between the bronchial and coronary circulations. The bronchial circulation provides nutrient supply to the neural structures of all species. The bronchial arteries themselves are innervated by sympathetic and parasympathetic nerves in all species studied. Evidence has been reported that neuropeptides are present in both afferent and efferent fibres innervating the bronchial arteries. The vasa vasorum of the pulmonary arterial system is derived from the bronchial arteries. Hence, bronchial artery blood composition may modulate pulmonary vasomotor responses. In pathological situations, the responses of the sheep's bronchial circulation are similar to those of the human.

Animals↗
PubMed1990

Responses of isolated cerebral arteries to vasoactive agents.

One hypothesis of cerebral vasospasm contends that the slow onset and eventual disappearance of the spasm of subarachnoid hemorrhage is caused by the finite production of spasmogens. These are generated and accumulate in the basal cisterns as the result of chemical reactions between blood elements, arterial wall, leptomeninges, and brain. The spasmogens may spread in the general direction of bulk CSF flow to affect arteries more distally. Pharmacodynamic studies performed on isolated cerebral arteries show that a vast array of naturally occurring substances are vasoactive. Among these, derivatives of arachidonate (eicosanoids) are strong candidates as spasmogens because they produce strong, prolonged contractions in human arteries and because the CSF levels of some eicosanoids are preferentially elevated in subarachnoid hemorrhage patients who experience severe spasm. The spasm may be largely refractory to treatment because the intravasation of blood elements and the coagulum serve as barriers to therapeutic agents and because cerebral arteries are devoid of vasa vasorum; however, in animal models of chronic subarachnoid hemorrhage, calcium antagonists given intrathecally will reverse the spasm. Other therapeutic strategems are being tried experimentally and clinically, including compounds like prostacyclin that relax cerebral arteries and inhibit platelets. In vitro studies indicate further that some plasma proteins (e.g., haptoglobin, antithrombin III) and several products of endothelial synthesis (PGI2, EDRF) may naturally provide protection against the genesis of vasospasm. The in vitro responses to bloody CSF are capricious but are not due to many pharmacologically defined substances, including hemoglobin. Hemoglobin and its derivatives, however, may be critical to the enhanced lipid peroxidation and free-radical production that occur in subarachnoid hemorrhage.

Animals↗
PubMedDate not supplied

Neointima formation on an antithrombogenic cardiac wall substitute that can be reconstructed by host cells.

The authors previously reported on a new cardiac wall substitute (collagen-coated ultrafine polyester mesh, CUFP), which in an animal study showed satisfactory antithrombogenicity due to its hydrophilicity and excellent neointimal formation because it induced cell migration and proliferation. Both the ultrafine polyester mesh, and the collagen cross-linked with a hydrophilic reagent, have a special affinity for host cells. In the current study, the focus was on neointima formation on the CUFP, compared with that on glutaraldehyde-treated equine pericardium (GA graft), over longer time periods. Twenty-one CUFPs, and 19 GA grafts as controls, were implanted as patches in the right ventricular outflow tract in 40 dogs. In the CUFP at 28 days, a thin neointima, which was almost endothelialized, had been formed. Fibroblasts and vasa vasorum were seen inside both the neointima and the graft wall. The CUFP showed a white, shiny, smooth, thin, and uniform neointima with endothilialization at 486 days, and the neointima was firmly anchored by day 699. In the GA graft at 484 days, however, the neointima was partly detached from the GA graft and almost no fibroblasts had infiltrated the graft wall. Therefore, neointimal formation on the CUFP is almost completed within 1 month and maintained over the long term.

Animals↗
PubMed1990

Histologic, morphometric, and biochemical evolution of vein bypass grafts in a nonhuman primate model. II. Modification of early changes by platelet inhibition with aspirin and dipyridamole.

The objective of this study was to determine the early influence of platelet inhibition on the histologic, morphometric, and biochemical evolution of vein bypass grafts in a nonhuman primate model. Cephalic vein grafts were interposed bilaterally in the femoral arteries of 15 stump-tailed macaque monkeys fed a diet that sustains plasma cholesterol levels of approximately 225 mg/dl. All animals received in combination aspirin, 80 mg/day, and dipyridamole, 50 mg/day. Grafts were excised from five animals for analysis on each of postoperative days 3, 7, 14, 30, 60, and 90. In animals subjected to platelet inhibition, cholesterol content in the graft was 170 +/- 52 micrograms/100 mg at 90 days, 205% of the level in ungrafted vein (p less than 0.01). This change was small in comparison with the increase to 686% of ungrafted vein observed in our study of control animals. In stepwise regression analysis, cholesterol content of grafts was best predicted by prevalence of foam cells (r2 = 0.82), and the proportion of intima as a fraction of total wall area was best predicted by the presence of macrophages (r2 = 0.69). Platelet inhibition did not decrease the extent of intimal hyperplasia. The prevalence of adherent platelets (r = -0.72) and the amount of fibrin (r = -0.78) correlated inversely with the amount of endothelium present during the first 14 days. The strength of these correlations declined with time, despite persistent lack of endothelium in some areas. Medial fibrosis occurred to the same extent as in control grafts, as did the early appearance of platelet factor VIII and fibronectin and the lack of vasa vasorum at 3 days followed by reappearance at 7 days. These data demonstrate that platelet inhibition dramatically reduces lipid uptake by grafts in the first 90 days but has less influence over histologic or morphometric changes.

Animals↗
PubMedDate not supplied

Comparative analysis of pseudointima biogenesis in Gelseal coated Dacron knitted graft versus crimped and noncrimped graft.

Twenty-one grafts (knitted crimped, 7; knitted Gelseal, 7; knitted no crimp, 7) of 7 cm long were inserted into 6 month-old mongrel puppies as infrarenal aortic tube grafts and retrieved at two-month intervals. All grafts were perfusion fixed in situ. Ex vivo arteriograms were obtained prior to processing for light (LM) and transmission electron microscopic (TEM) studies of tissue ingrowth into the grafts. All grafts were patent at the time of harvesting. The thickness of pseudointima plateaued at 10 weeks. There was no demonstrable discrepancy in thickness between grafts (cell 72 +/- 13). The luminal cells were modified myofibroblasts that contained short microvilli, gap junctions, myofilament, and incomplete basal laminae. The pseudointima consisted of an interlamination of myofibroblasts alternating with extracellular matrix of collagen and ground substances. It was more cellular near the lumen and more fibrocollagenous near the graft. Myofibroblasts were found near the lumen and fibroblasts near the graft. Macrophages, vasa vasorum, leukocytes and fibroblasts occupied the interstitial space between the graft fibrils. Similar cellular and extracellular composition existed in the three types of grafts. There was no local inflammatory reaction encountered in the Gelseal treated graft. Gelseal, crimped and noncrimped knitted Dacron grafts had pseudointima of comparable architecture, thickness, cellular and noncellular composition. Gelseal did not hinder pseudointima formation or induce local inflammatory reaction.

Animals↗
PubMed1989

[Blood supply of the main vessels in laboratory rats and rabbits].

The vascular bed in 25 rabbits and 25 white rats has been revealed by means of vital injection of Indian ink into the intraorganic vessels, staining of erythrocytes (benzidine reaction) and silver impregnation. In preparations of the aorta, inferior and superior vena cava diameter of the vessels, the wall and middle membrane thickness, amount of elastic membranes have been measured. Ramification of small vessels and capillaries are revealed only in the paravasal tissues, surrounding the aorta and veins. In serial sections it has been stated that at their greatest extent vasa vasorum has no walls and only in places, where the intercostal (or others) vessels get out of the aorta in its middle or external tunics, a limited, as to its spread, network of intramural vessels exists. The morphometrical analysis does not show any regular connection between the vascular diameter, wall thickness, or middle membrane thickness, amount of elastic membranes in it with presence or peculiarities in distribution of the intramural vessels.

Animals↗
PubMed1985

Spontaneous renal infarction due to polyarteritis nodosa. A case report.

A case of spontaneous infarction of the kidney due to polyarteritis nodosa of the vasa vasorum of the right main renal artery is reported. The diagnosis was unsuspected until histological examination of a nephrectomy specimen revealed the typical vascular changes in the renal arterial wall.

Adult↗
PubMed1987

Pathogenesis of aneurysm formation opposite prosthetic patches used for coarctation repair. An experimental study.

Patch graft angioplasty for coarctation repair has been associated with late aneurysm formation opposite the prosthetic patch in some patients. Etiologic possibilities for this aneurysm formation include congenital abnormality of the aortic wall, surgical interruption of the vasa vasorum, intimal disruption because of extensive excision of the coarctation web, and rigidity of the prosthetic patch. To assess the effect of extensive intimal excision on the development of aneurysms, we operated on 12 dogs, performing a left thoracotomy and aortoplasty with Dacron (n = 6) or polytetrafluoroethylene patches (n = 6) and concomitant intimal excision opposite the patch. Ten control dogs underwent angioplasty with Dacron (n = 5) and polytetrafluoroethylene patches (n = 5) without excision of the intima. Serial aortograms of all animals showed aneurysm formation of the aorta opposite the patch in eight of the 12 dogs undergoing intimal excision. In contrast, no aneurysms developed in the control dogs (p less than 0.001). An additional five dogs underwent longitudinal aortotomy, intimal excision, and primary closure. Three dogs in this group demonstrated an aneurysm angiographically (p less than 0.02). Histologic analysis of the aneurysms and the control aortas revealed hyperplastic ingrowth of the intima over the denuded surface in the animals undergoing intimal excision. The elastic fibers in the media were intact and organized except in two aneurysmal specimens. We conclude that extensive resection of the intima with or without patch angioplasty predisposes aneurysm formation opposite the aortotomy and should be avoided during coarctation repair.

Animals↗
PubMed1988

Arterial elastin as seen with scanning electron microscopy: a review.

All large arteries contain elastin, collagen, and muscle which can be seen with light microscopy and transmission electron microscopy. Elastin forms an internal elastic lamina (IEL) in all arteries, but also forms multiple fenestrated sheets in the media of the aorta and other large arteries. The fenestrations in the media are larger than those in the IEL. The adventitial elastin is more fibrous and often contains tubular elastin surrounding vasa vasorum when prepared by removing all non-elastin by placing the aorta in 0.1 N NaOH at 70-75 degrees C for five hours. The fenestrations are larger near branches and in an experimentally created poststenotic dilatation. Atherosclerosis appears associated with both new elastin formation in early atherosclerosis and elastolysis in late disease.

Animals↗