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PubMed1991

Organisation and reorganisation of blood vessels in embryonic development.

The initial establishment of blood vessels is genetically predetermined but it is subsequently supplemented by local and haemodynamic factors. The earliest embryonic vessels arise independently in the mesenchyme of the yolk sac wall, chorion and embryonic disc. The angioblasts aggregate as cords which canalise by a process which includes intracellular vacuolation. Subsequent extension of the network occurs by a combination of (1) in situ formation of new vessels, (2) sprouting and fusion of established neighbouring vessels and (3) invading angioblasts from other regions. As capillaries mature, a basement membrane is established containing collagen IV, laminin, nidogen/entactin, heparan sulphate proteoglycan and a variable amount of fibronectin. Early capillary basement membrane contains more fibronectin which promotes proliferative and migratory activity of endothelium. As vessels mature, the endothelium switches to laminin secretion which causes differentiation including cell attachment, junction formation and establishment of tubes while cell proliferation is suppressed.

Basement Membrane↗
PubMed1995

Vasomotor nerves of vessels in the human optic nerve.

Aminergic and cholinergic vasomotor nerves in vessels of the human optic nerve were studied morphologically. Aminergic nerve fibers were observed by the glyoxylic acid method. Cholinergic nerve fibers were observed by light microscopy after acetylcholinesterase staining by the Karnovsky-Roots method and Tago's modified method. In the retrobulbar optic nerve behind the bulbus, aminergic and cholinergic vasomotor nerves were observed to be dense in the central retinal artery and vein and posterior ciliary arteries. A large number of vasomotor nerves were also demonstrated in vessels in the septum of the optic nerve, but they were sparse in pial vessels. Further centrally, a few vasomotor nerves were found in pial vessels of the intracanalicular and intracranial optic nerve, but few were observed in the septum of the optic nerve. At the optic chiasm they were densely distributed in pial vessels.

Acetylcholinesterase↗
PubMed1999

The effect of diameter ratio between vascular substitute and blood vessel on anastomosis.

It is necessary to maintain mechanical compatibility between a blood vessel and a vascular substitute to promote encapsulation around the anastomosed part. From this point of view, using linear elastic theory, we had previously performed stress analyses at the part anastomosed by tissue adhesion, in order to propose some methods of preventing stress concentration at this junction. In this study, based on the previous analyses, we have attempted to develop a concept that can be applied under the conditions of operation. That is, the initial diameter of a vascular substitute with high rigidity is chosen larger than that of a blood vessel. This will reduce the stress concentration around the anastomosed part, on average, during expansion of the blood vessel. We analysed the optimum diameter ratio between the vascular substitute and the blood vessel which causes the least stress concentration, on average, during this process, using linear elastic theory. Furthermore, numerical analyses of blood vessel deformation were performed using various nonlinear stress-strain laws. These results were compared to the analytical solution based on linear elastic theory.

Anastomosis, Surgical↗
PubMed1991

Acoustical imaging and processing of blood vessel and the related materials using ultrasound Doppler effect.

In the present paper a method is proposed to measure the degree of the degradation of the elasticity in natural blood vessel and the related materials by using ultrasound Doppler effect. It was found that the deformation rate and its acceleration in the radial direction of the blood vessel can be detected by acoustical imaging and processing using this method. These results were proven to correspond to the degree of the degradation of the elasticity, that is, the degree of viscoelasticity in the blood vessel from the wave versus time pattern detected and its simple analysis. This method was applied to predicting the arteriosclerosis of blood vessels of humans by acoustical imaging and processing uninvadedly, as the characteristics of viscoelasticity in blood vessels.

Algorithms↗
PubMed2004

Role of precoating in artificial vessel endothelialization.

As the progress of vascular surgery, artificial vessels have become the substitute for large and middle diameter vessels but have not for small diameter ones owing to thrombogenesis and occlusion within a short period of time after being applied. Artificial vessel endothelialization is one of the ideal methods to resolve such issue and has been improved continuously since Herring in 1978 put forward this term in the first time and utilized vascular endothelial cells (ECs) harvested from living animals to perform the test of artificial vessel endothelialization. However, human endothelial cells show little adhesion to the currently available vascular graft materials and some expanded polytetrafluoroethylene (ePTFE) grafts have shown only 10%+/-7% endothelial cell attachment rate (ECA, ie, attachment of ECs when incubated in vitro). Moreover, when the graft is exposed to pulsatile blood flow, a high proportion of cells are washed off from the lumen. Maximum cell loss occurs in the first 30-45 min after exposure to pulsatile flow, with up to 70% of cells lost. After that, a slower exponential loss occurs over the next 24 h. The lack of retention of cells could be partly overcome by sodding, but other techniques, involving engineering the lumen to improve ECA and endothelial cell retention rate (ECR, ie, retention of ECs when the grafts are exposed to pulsatile flow) have been developed. These include shear stress preconditioning, electrostatic charging and, above all, most successfully to date, precoating with EC specific adhesive glues that are mostly found in the extracellular basement membrane of blood vessels. The commonest are chemical coatings, preclotting, chemical bonding, and surface modifications.

Blood Vessel Prosthesis↗
PubMed1996

Clinical and angiographic outcome of elective stent implantation in small coronary vessels: an analysis of the BENESTENT trial.

We examined the influence of vessel size using an intention-to-treat approach in 259 patients who underwent stent implantation and in 257 patients who underwent balloon angioplasty alone in the BENESTENT trial. In the stented population, smaller vessel size was associated with a higher stent:vessel ratio, a greater relative gain and a greater subsequent loss index, and a higher risk of adverse cardiac events. In the balloon angioplasty population small vessel size conveyed an increased requirement for revascularization but did not increase the risk of procedural failure or myocardial infarction during follow-up. Logistic regression indicated that decreasing vessel size (as a continous variable) was associated with an increasing risk of a cardiac event for both the stent and balloon angioplasty populations.

Angioplasty, Balloon, Coronary↗
PubMed2005

Lymphatic vessel density, nodal metastases, and prognosis in patients with head and neck cancer.

OBJECTIVE: To examine the relationship between intratumoral lymphatic vessel density and clinical and pathological variables in patients with head and neck squamous cell carcinoma. DESIGN: Archived paraffin-embedded biopsy specimens were sectioned and stained with hematoxylin-eosin and anti-LYVE-1 antibody, a highly specific marker for lymphatic endothelium. Tumor grade, infiltrating margin, inflammatory infiltrate, and percentage of tumor necrosis were noted and lymphatic vessel density measured using Chalkley point counting. SETTING: Tertiary care center at a university hospital. PATIENTS: A total of 168 previously untreated patients with advanced squamous cell carcinoma (73, larynx; 62, oropharynx; and 33, hypopharynx) treated with primary radiation (with or without planned neck dissection) and salvage surgery from 1992 to 1999. INTERVENTIONS: Measurement of intratumoral lymphatic vessel density in pretreatment tissue biopsy specimen. MAIN OUTCOME MEASURES: Disease-free and disease-specific survival, tumor occurrence, and nodal status. RESULTS: In patients with laryngeal carcinoma there was a significant relationship between the presence of intratumoral lymphatics and nodal metastases at presentation (P = .02) and poorly differentiated tumor grade (P = .02). Patients with high lymphatic vessel density also had a significantly worse disease-specific survival (P = .03). However, this difference was not significant with multivariate analysis. No significant relationship existed between the presence of intratumoral lymphatics and any of the clinical or pathological variables in oropharyngeal and hypopharyngeal carcinoma. CONCLUSIONS: In this patient sample, the development of intratumoral lymphatics in laryngeal carcinoma, but not in oropharyngeal or hypopharyngeal carcinoma, is associated with a spread of the tumor to regional lymph nodes. Detecting tumor lymphatic vessel proliferation is another step in the understanding of tumor biology, and the targeting of lymphatic growth may be of potential therapeutic benefit in selected patients with head and neck squamous cell carcinoma.

Aged↗
PubMed1997

The development of the coronary vessels and their differentiation into arteries and veins in the embryonic quail heart.

Research concerning the embryologic development of the coronary plexus has enriched our understanding of anomalous coronary vessel patterning. However, the differentiation of the coronary vessel plexus into arteries, veins, and a capillary network is still incomplete. Immunohistochemical techniques have been used for whole mounts and serial sections of quail embryo hearts to demonstrate endothelium, vascular smooth muscle cells, and fibroblasts. From HH35 onward, the lumen of the coronary plexus was visualized by injecting India ink into the aorta. In HH17, branches from the sinus venosus plexus expand into the proepicardial organ to reach the dorsal side of the atrioventricular sulcus. From HH25 onward, vessel formation proceeds toward the ventral side and the apex of the heart. After lumenized connections of the coronary vessels with the aorta and right atrium are established, a media composed of smooth muscle cells and an adventitia composed of procollagen-producing fibroblasts are formed around the coronary arteries. In the early stage, bloodflow through the coronary plexus is possible, although connections with the aorta have yet to be established. After the coronary plexus and the aorta and right atrium are interconnected, coronary vessel differentiation proceeds by media and adventitia formation around the proximal coronary arteries. At the same time, the remodeling of the vascular plexus is manifested by disappearance of arteriovenous anastomoses, leaving only capillaries to connect the arterial and venous system.

Animals↗
PubMed1998

Morphological characteristics and distribution pattern of the arterial vessels in human cerebral cortex: a scanning electron microscope study.

BACKGROUND: The human cerebral cortex is supplied by vessels that arise from the pial arteries. These vessels give rise to a dense vascular network that is highly interconnected. Cortical arteries have been classified in different categories. Both their angioarchitectonic pattern and anatomical structures involved in their regulation are not fully understood. METHODS: Twelve fresh human brains were studied by scanning electron microscopy of vascular corrosion casts. RESULTS: Four types of arterial vessels in the cerebral cortex--short, middle, long, and transcortical--were identified. The cortical vascular network was formed by several interconnected clusters of vessels, which were arranged in four vascular layers parallel to the pial surface and characterized by different vascular densities. The greatest vascular density corresponded to the middle and deep vascular layers. Circular constrictions were found at the origin of cortical arteries and at their branching sites, probably related to vascular sphincters. Connections between cortical arteries were observed at their initial course. Plastic strips, occasionally related to constrictions, were observed around both middle and long cortical arteries. Other plastic structures, morphologically similar to pericytes, were found around capillary vessels. CONCLUSIONS: The blood supply to the human cerebral cortex depends on the short, middle, and long cortical arteries, which give rise to a highly anastomosed capillary network. There exist vascular connections between pial arteries and occasionally between cortical arteries. Blood flow autoregulation is probably mediated by smooth muscle cells at the arteriolar level and by pericytes at the capillary level, through endothelial connections.

Adult↗
PubMed1991

Endothelial cell origin and migration in embryonic heart and cranial blood vessel development.

Using the QH-1 monoclonal antibody as a marker for quail endothelium, blockage and transplant experiments were carried out to construct fate maps for the embryonic endocardium, to determine whether preendocardial angioblasts are migratory, and, if these cells are migratory, to outline the pathways that they use for directed migration in embryonic blood vessel development. Recent descriptive studies using QH-1 to make immunofluorescent whole mounts have described a sequence of events leading to the establishment of the embryonic heart tube. These reports suggest that the pattern for the endocardium and cranial vasculature is established by migrating angioblasts that form vascular cords which mature into blood vessels. Blockage experiments showed that the ventrolateral edge of the anterior intestinal portal serves as a substrate for the directed migration of pre-endocardial angioblasts and that the pattern of the cranioventral vasculature forms independent of the source of angioblasts. Transplant experiments showed that the origin for endocardial angioblasts lies in mesodermal tissue just anterior to Henson's node, that these cells undergo directed migration to the pericardial area, and that angioblasts are pluripotent with the ability to form different blood vessels. The transplant studies also showed that the embryonic mesoderm may contribute to extraembryonic blood vessels on the embryonic yolksac. These results support the hypothesis that embryonic blood vessels may develop by either the vasculogenesis or by the angiogenesis mechanism, and show that the endocardium of the primitive heart tube forms by vasculogenesis.

Animals↗
PubMed2003

Blood flow velocity in donor coronary artery depends on the degree and pattern of collateral vessel development: a study using thrombolysis in myocardial infarction frame count method.

To understand the influence of collateral vessels on the coronary flow, TIMI frame count (TFC) method was applied as a measure of mean coronary blood flow velocity in artery giving collateral blood supply to the other artery in angiograms of 76 patients with single occluded coronary artery: RCA giving collaterals to occluded LAD or LAD giving collaterals to occluded RCA. As a control group, TFC was applied in angiograms of 30 patients with mild or no coronary artery disease. TFC was lower (faster blood flow) in LAD giving collaterals to occluded RCA (43 patients) than in LAD in control group (21.8 +/- 10.5 vs. 33.9 +/- 20.8 frames; P < 0.01). Higher degree of collateral vessels (Rentrop classification) and mixed- and distal-type collaterals (through the interventricular septum and heart apex) was associated with lower TFC. There was no difference in TFC in the RCA giving collaterals to an occluded LAD (33 patients) compared to the TFC in RCA in control group (16.6 +/- 9.0 vs. 18.5 +/- 6.0; P = NS), even in angiograms with higher degree of collateral vessel development. TFC was lower (faster blood flow) only in subgroups with mixed (proximal and distal types together in the same patient) and distal (through the interventricular septum and the apex of the heart) collateral types. A delayed contrast appearance in occluded LAD compared to occluded RCA has been found (35.1 +/- 16.1 vs. 20.2 +/- 7.3 frames; P < 0.001) with earlier contrast appearance in occluded LAD when proximal collateral vessels (through the conal and acute marginal branches of RCA) were presented. The coronary flow in donor arteries depends not only on the degree but also on the pattern of collateral vessels. The simple TFC method may facilitate the study of collateral filling pattern and offer insight into the influence of collaterals on the ventricular function.

Analysis of Variance↗
PubMed1981

Comparison of coronary arteriographic and left ventriculographic findings in patients with single, double, and triple vessel disease and angina pectoris.

The distribution and severity of coronary artery disease and degree of left ventricular dysfunction are described in 500 patients with single (103), double (119), and triple (278) vessel disease and angina pectoris. The coronary arterial patterns were divided into right (360), mixed (89), and left (51) systems, depending upon the blood supply to the inferior surface of the left ventricle. The following relationships were noted: 1) Coronary arterial patterns of right, mixed, and left systems do not influence the presence, distribution, or severity of coronary arterial lesions among patients with single, double, and triple vessel disease and angina pectoris. 2) Analysis of the distribution of lesions among patients with single and double vessel disease reveals that the circumflex/obtuse marginal arteries contribute least of the three major coronary arteries to angina pectoris. 3) Lesions of 70-90% reduction in coronary arterial luminal diameter are the most common, and 90-99% lesions are the least common. The latter are least stable among patients with both coronary artery disease and angina pectoris. 4) Quantitatively there is progression of both coronary artery disease and left ventricular dysfunction as one moves from single to double and then to triple vessel disease. However, the pattern of coronary arterial lesions (50-70%, 70-90%, 90-99%, and 100% reduction of luminal diameter) and the pattern of left ventricular dyssynergy (hypokinesis, akinesis, and dyskinesis) are similar among the patients with single, double, and triple vessel disease and angina pectoris.

Angina Pectoris↗
PubMed1994

Local intramural drug delivery using an infusion balloon following angioplasty in normal and atherosclerotic vessels.

Local intramural delivery of various pharmacologic agents following angioplasty has been proposed as a means of reducing restenosis. This study tested whether local intramural delivery of aqueous solutions using an infusion balloon could be accomplished safely in normal vessels and whether such infusion was safe following standard angioplasty in diseased vessels. Infusion of aqueous agents into normal canine arteries had no adverse effect. Infusion of several aqueous agents (< or = 4 cc at 4 atm) into diseased swine iliac arteries following balloon angioplasty did not worsen existing or create new dissections. Histologically, infusion treated vessels did not differ in either model from vessels treated with angioplasty alone. We conclude that local intramural drug infusion does not create new, or worsen existing, dissections produced during standard balloon angioplasty in diseased vessels.

Angioplasty, Balloon, Coronary↗
PubMed2002

Skin blood vessels are simultaneously innervated by sensory, sympathetic, and parasympathetic fibers.

Despite the known major role of skin blood vessel innervation in blood flow control, particularly in disease, little information on the co-innervation of blood vessels by sensory and autonomic fibers and the relationships of these fibers to one another is available. To fill this gap, we performed a light and electron microscopic analysis of the innervation of skin vessels by sensory and autonomic fibers by using the rat and monkey lower lips as a model. In rats, double-labeling immunocytochemistry revealed that combinations of fibers immunoreactive for substance P (SP) and dopamine-beta-hydroxylase (DbetaH), SP and vesicular acetylcholine transporter (VAChT), as well as DbetaH and VAChT occurred only around blood vessels in the lower dermis. All fiber types travelled in parallel and in close proximity to one another. In the upper dermis, blood vessels were innervated by SP-containing fibers only. Although nerve terminals displayed synaptic vesicles, synaptic specializations were never observed, suggesting that, in this territory, these fibers do not establish synaptic contacts. Quantification of the distance between the various immunoreactive terminals and their presumptive targets (smooth muscle cells and endothelial cells) revealed that both sympathetic and parasympathetic fibers were significantly closer to the endothelial cell layer and smooth muscle cells compared with sensory fibers. In monkeys, double-labeling immunocytochemistry was performed for SP-DbetaH and SP-VAChT only. The results obtained are similar to those found in rats; however, the fiber density was greater in monkeys. Our findings suggest that the regulation of skin microcirculation might be the result of the coordinated functions of sensory and autonomic fibers.

Animals↗
PubMedDate not supplied

Retrospective registration of X-ray angiograms with MR images by using vessels as intrinsic landmarks.

Conventional x-ray angiography (XRA) images are projections of the vasculature with high spatial and temporal resolution, while magnetic resonance (MR) angiography (MRA) and MR imaging data show the three-dimensional locations of vessels relative to brain parenchyma. The authors have developed a retrospective method of registering these studies, which makes it practical to produce multimodality displays of this complementary information. Registration was performed by matching vessels seen on both XRA and MRA images. First, the authors determined the coordinates of the center lines of a few "landmark" vessels on the XRA image and the three-dimensional locations of the corresponding intraluminal voxels in the MRA volume. Registration was performed by rotating and translating the MRA-MR imaging volume until the perspective projection of the MRA landmark vessels matched the corresponding vessel center lines on the XRA image. Experiments with phantoms and patients indicated that the two studies were registered with an average error of less than 2 mm. A linked-cursor display was developed to show correspondence between points on the registered XRA and MRA-MR images.

Angiography↗
PubMedDate not supplied

Vessel enhancement filtering in three-dimensional MR angiograms using long-range signal correlation.

Small vessels in three-dimensional MR angiograms have low visibility in maximum-intensity projection images because of their low contrast. In a previous study, we had two nonlinear filters that appeared to give significant improvement in small vessel detail. In this paper, we report on a generalization of this filter that allows a more general modeling of the vessels and a more complete suppression of background. One implementation of the general filter gave a vessel mean contrast-to-noise ratio that is 2.52 and 3.51 times higher than the vessel mean contrast-to-noise ratio obtained using our previously reported maximum-minimum (max-min) filter and cross-section filter, respectively.

Blood Vessels↗
PubMed2007

Dynamic imaging of contrast-enhanced coronary vessels with a magnetization prepared rotated stripe keyhole acquisition.

PURPOSE: To evaluate dynamic coronary imaging based on a magnetization prepared contrast-enhanced (CE) rotated stripe keyhole acquisition scheme. MATERIALS AND METHODS: Background suppression of long T(1) tissue was used so that the k-space would be selectively dominated by the contribution of the CE vessel. The phase-encoding axis was then adjusted parallel to the long axis of the vessel to sample the significant power spectrum of the vessel. The performance of this approach was evaluated by means of computer simulations and experimental studies on phantoms and a pig model instrumented with an intracoronary catheter for infusion of contrast media. RESULTS: Computer simulations and phantom studies demonstrated that by rotating the gradient axes to match the k-space pattern of the frequency spectrum, one can reduce the keyhole band to 20% of the full k-space while preserving the structure's lumen width and sharpness. In vivo studies validated those findings, and dynamic angiograms of the CE coronary arteries were obtained as rapidly as 140 msec per image, with an in-plane spatial resolution of 1.5 mm. CONCLUSION: With efficient background suppression, a rotated stripes keyhole acquisition can efficiently acquire the significant k-space of a CE vessel, and provide improved vessel definition with a reduced acquisition matrices scheme.

Animals↗
PubMed2003

Experimental evaluation of possible side effects of intra-operative photodynamic therapy on rabbit blood vessels and nerves.

BACKGROUND AND OBJECTIVES: Tumours of the head and neck show a high local tumour recurrence rate ranging between 7 and 30% despite combined treatment modalities. To improve these data, photodynamic therapy (PDT) might be used as an additional treatment besides surgery and radio-chemotherapy. Intra-operative PDT has been proposed to "sterilise" the tumour bed after surgical tumour resection in order to kill any remaining tumour cells which are responsible for local tumour recurrences. Often, during head and neck surgery, large blood vessels and important nerve structures are exposed and could potentially be harmed by intra-operative PDT. Despite the fact that mTHPC is the most commonly used photosensitiser for head and neck tumours, there are no data on potential detrimental side effects of intra-operative PDT onto these vital structures. The purpose of this study was to use a maximal treatment protocol in rabbit observing possible damage to the blood vessels and nerve structures and thus judge the most severe event that could happen in patients. STUDY DESIGN/MATERIALS AND METHODS: In rabbits the large blood vessels and nerve structures at the neck and at the groin area were surgically exposed and treated by mTHPC-mediated intra-operative PDT. Various treatment parameters (drug-light interval, light dosage, follow up interval) were modified in order to find the critical treatment parameters which might cause maximum tissue effects. The intention was to define the most severe clinical complications which could be expected from mTHPC mediated intra-operative PDT. RESULTS: The most severe tissue reactions were found at a drug dosage of 0.3 mg/kg, a drug-light interval of 24 hours and a light dosage of 20 J/cm(2). Complete necrosis was found for the muscles, fat and connective tissue within the entire treatment field. Blood vessels demonstrated severe oedema, media-hyperplasia or loosening of the endothelial layer leading to various degrees of local thrombosis but no break down of the vessel wall or any rupture was noted. Most nerves were altered by a 75% demyelisation but this did not result in any clinical symptoms. CONCLUSIONS: Our results have shown that mTHPC mediated intra-operative PDT used with a maximal treatment protocol (very high doses and very short drug-light intervals) has significant histological impact onto all tissue structures, but did not show any clinical symptoms in rabbits. mTHPC mediated intra-operative PDT seems to be a promising and a safe treatment option which could complement existing treatment modalities in order to improve total survival rate of tumour patients.

Animals↗