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PubMed1985

Embolization and vessel wall perforation in argon laser recanalization.

The primary concerns in the development of a laser catheter for intravascular use are the potential hazards of vessel wall perforation and distal embolization. We present evidence, using technetium 99-labeled thrombi in two rabbit aortas and one human cadaver coronary artery, that distal embolization does not occur after argon laser recanalization. Also, no vessel wall perforation was observed during recanalization of 15 thrombosed rabbit aortas and 1 inferior vena cava, used because of their extremely thin walls. Laser recanalization of three peripheral arteries with atherosclerotic plaque obstruction, in amputated human legs, showed no evidence of vessel wall perforation. The incidence of vessel wall perforation can be minimized by preferential use of the argon laser, strict maintainance of a coaxial relationship between the laser catheter and the vessel, and exercising care during the actual lasing process. Distal embolization does not appear to be an important consideration.

Animals↗
PubMed1990

Effects of Nd: YAG laser coagulation of myocardium on coronary vessels.

Laser coagulation of arrhythmogenic myocardium proved to be an effective surgical therapy for refractory arrhythmias. To determine the influence of Nd: YAG laser coagulation of myocardium on coronary vessels, a total of 48 transcatheter laser impacts (10 W, 10 sec, 7 W mm2) were directed to the left ventricular free wall via endocardial (24 lesions in 2 dogs) or epicardial (24 lesions in 2 dogs) approach. In 8 of 24 endomyocardial lesions (2 and 6 months old) coronary vessels with a diameter of greater than 50 microns were found within the coagulation zones. The volume of these lesions was significantly (P less than 0.01) smaller (139 +/- 43 mm3) than those (n = 16) with coronary vessels measuring less than 50 microns (311 +/- 87 mm3). Volumes of epimyocardial lesions (1-2 hours old) produced by transcoronary irradiation with normal coronary blood flow were significantly (P less than 0.01) smaller (31 +/- 17 mm3) than with reduced (73 +/- 22) or interrupted (119 +/- 34 mm3) blood flow (n = 8, each). Both directly irradiated coronary vessels and those found within the coagulation zones and scars appeared histologically normal through all layers with an intact intima without fibrosis or thrombosis. The ultrastructure of irradiated arteries, even with total interruption of blood flow, was no different from that of non-irradiated controls. Thus, coronary artery blood flow significantly reduces the volume of coagulated myocardium, whereas the vessels themselves appear to remain undamaged by laser irradiation as used for myocardial coagulation.

Animals↗
PubMed1995

Blood flow rate and total blood flow related to length density and total length of blood vessels in mini-pig urinary bladder after chronic outflow obstruction and after recovery from obstruction.

Chronic partial bladder outlet obstruction was created in mini-pigs by implanting a 6-7 mm ring around the proximal urethra. After a median obstruction period of 63 days the ring was removed, and after a median recovery period of 60 days the animals were sacrificed. At each study occasion the blood flow rate (ml per 100 g per min) was measured by washout of locally injected 133Xe in the bladder wall and the washout curves analyzed by the corrected initial slope method. Stereological estimation of length density and total length of blood vessels in the bladder were performed. The results can be summarized as follows: (1) no differences in the blood flow rate at the time of ring implantation, obstruction, or recovery, (2) no decrease in the blood flow rate in normal bladders after bladder distension, (3) a significant decrease in blood flow rate in obstructed bladders after distension, (4) a 6-fold increase in total bladder blood flow after obstruction, (5) an unchanged blood flow per length of blood vessels per min during the study, (6) no changes in length densities of blood vessels during the study, and (7) a 7-fold increase in total length of blood vessels after obstruction and reversion to control level after recovery. The unchanged blood flow per length of vessels implies that capillary proliferation matched the increased bladder mass during the study.

Animals↗
PubMed2005

Topographic distribution of lymphatic vessels in the normal human prostate.

BACKGROUND: The lymphatic endothelial hyaluronan receptor (LYVE-1) is a specific cell surface protein in lymphatic endothelium. The antiserum against human LYVE-1 was developed and was confirmed a powerful marker of lymphatic endothelium in human organs. With this novel marker we investigated the small network of intraprostate lymphatic vessels. METHODS: To identify intraprostatic lymphatic vessels, we performed an immunohistochemical staining method using LYVE-1 pAb and von Willebrand Factor (vWF), and assessed the difference in distribution of small lymphatic vessels between the components in the prostate. RESULTS: The density of lymphatic vessel was significantly high around ejaculatory ducts and in the fibromascular area between the globular area of peripheral zone and transitional zone. Predominat lymphatic vessels distributed in the fibromascular area in the anterior and posterior prostate of extrastromal area. CONCLUSIONS: Recognition of the distinctive features of the intraprostate lymphatic network, can help the investigation of lymphatic involvement in cancer of the prostate.

Biomarkers↗
PubMed1978

Drug effects on platelet adherence to collagen and damaged vessel walls.

The interaction of platelets with damaged vessel walls leads to the formation of platelet-fibrin thrombi and may also contribute to the development of atherosclerotic lesions because platelets adherent to exposed collagen release a mitogen that stimulates smooth muscle cell proliferation. The first step in thrombus formation, platelet adherence to an injured vessel wall, can be studied quantitatively by the use of platelets labeled with 51chromium. In these investigations, rabbit aortas were damaged by passage of a balloon catheter and segments of the aortas were everted on probes that were rotated in platelet suspensions. Collagen-coated glass cylinders were also used. Adherence was measured in a medium containing approximately physiologic concentrations of calcium, magnesium, protein and red blood cells. Conditions of testing influence the effect of non-steroidal anti-inflammatory drugs, sulfinpyrazone, and dipyridamole on platelet adherence. Aspirin and sulfinpyrazone were not inhibitory when tested in a medium with a 40% hematocrit; this indicates that products formed by platelets from arachidonate probably do not play a major part in the adherence of the first layer of platelets to the surface, although they may be involved in thrombus formation. Indomethacin, dipyridamole, prostaglandin E1, methylprednisolone and penicillin G and related antibiotics did inhibit platelet adherence although the concentrations required were higher than would likely be achieved in vivo upon administration to human patients. None of the non-steroidal anti-inflammatory drugs inhibited the release of granule contents from adherent platelets. Pretreatment of the damaged vessel wall with aspirin increased platelet adherence, presumably because it prevented the formation of PGI2 by the vessel wall. Platelet adherence to undamaged or damaged vessel walls was enhanced by prior exposure of the wall to thrombin. Platelet reactions with aggregating agents and platelet survival can be modified by changes in dietary lipids but there is very little evidence concerning the effects of lipids on platelet adherence. If some forms of dietary fat damage the endothelium, platelet interaction with the damaged area and release of the mitogen for smooth muscle cells would contribute to the development of atherosclerotic lesions.

Animals↗
PubMed1995

Reduced laminin immunoreactivity in the blood vessel wall of ageing rats correlates with reduced innervation in vivo and following transplantation.

Changes in extracellular matrix composition and/or organization, and in particular in the ratio of axonal growth-promoting components such as laminin to growth-inhibiting molecules, could contribute to the degenerative changes observed in the innervation of some peripheral tissues in old age. We have investigated this issue by evaluating laminin content or accessibility at various locations on blood vessels where we had previously studied age-related alterations in innervation density. We have employed a morphological approach, measuring laminin immunoreactivity by a densitometric application of confocal microscopy, because more conventional biochemical techniques would have been unable to distinguish specific, localized changes in laminin at sites accessible to nerves from heterogeneous changes in other areas of the vessel wall, such as the endothelial basal lamina. We found that in 24-month-old rats laminin immunoreactivity is decreased by 50% at the medial-adventitial border in association with the outer layer of smooth muscle cells, where a parallel decrease is observed in innervation density. Axonal terminals were shown to have access to laminin in this region of the blood vessel wall by double staining with laminin and a general neuronal marker. Changes in laminin immunoreactivity were region-specific on the same blood vessel, thus excluding the possibility of a generalized decrease in immunoreactivity in old age. For example, in the basilar artery intensity of laminin immunoreactivity decreased in old age at the medial-adventitial border, but showed no change in endothelial cell basal lamina and in the adventitia. Moreover, we performed in oculo transplants of blood vessels displaying differences in laminin immunoreactivity and found that the density of innervation correlated with the intensity of laminin staining, thus lending further support to the hypothesis that laminin might play a role in nerve fibre atrophy in old age.

Aging↗
PubMed1992

Ultrastructural studies of the cells forming amyloid in the cortical vessel wall in Alzheimer's disease.

Ultrastructural studies of serial sections of the vessels with amyloid deposits in the brain cortex of patients with Alzheimer's disease showed that cells in the position of pericytes--perivascular cells--and perivascular microglial cells are producers of amyloid fibrils in the vascular wall. Three types of changes from normal are distinguishable in the vessel wall: (1) semicircular or circular thickening of vascular wall containing a large amount of amorphous material and various number of amyloid fibrils, (2) tuberous amyloid deposits containing both amorphous material and amyloid fibrils, some of the fibrils being arranged in strata and others arranged radially, and (3) amyloid star composed of a predominantly radial arrangement of bundles of amyloid fibrils and a less prominent amorphous component. A mixture of amorphous material and amyloid fibrils is present in cell membrane invaginations of perivascular cells, and occasionally perivascular microglial cells. Bundles of amyloid fibrils are found in altered cisternae of the endoplasmic reticulum and in the channels confluent with the infoldings of the plasma membrane of perivascular microglial cells. The amyloid deposition in the wall of the vessel causes degeneration of endothelial cells and the reduction of, and in some vessels obliteration of, the vessel lumen. In areas affected by amyloid angiopathy, extensive degeneration both of the neuropil and of neurons was observed. These changes were accompanied by astrogliosis. This study demonstrates similarities in amyloid formation in amyloid angiopathy and in beta-amyloid plaques in the neuropil and suggests that cells of the mononuclear phagocyte system of the brain (perivascular cells and perivascular microglia) are engaged in amyloid fibril formation.

Aged↗
PubMed1988

Evaluation of micrometric and microdensitometric methods for measuring the width of retinal vessel images on fundus photographs.

The width of retinal vessel images on fundus photographs was determined by projection micrometry and microdensitometry. These methods were evaluated on 12 retinal vessels using the negatives of 570-nm monochromatic fundus photographs. For projection micrometry, the intraobserver reproducibility of vessel width measurements was 1.6%-2.9%, depending upon the experience of the observer. Significant interobserver differences in the measured widths were demonstrated. For microdensitometry, three distinct measurement criteria were used. Significant differences in width as measured by the three criteria were found, but there were no interoperator differences for each criterion. The intraoperator reproducibility of vessel width measurements by microdensitometry was 2.1%-2.5%. Significant differences were found in the vessel widths determined by the micrometry and densitometry methods, and results obtained by micrometry are discussed in terms of edge-detection phenomena.

Adult↗
PubMed1981

Processess of revascularization between the jejunal submucosal vessel and implanted epiploic vascular pedicle.

Revascularization between the proper submucosal vessels of the jejunum and the epiploic vessels implanted in the submucosal layer of the jejunum was experimentally studied by a panoramic montage technique of micro-angiograms in dogs. A vascular network was found between the implanted epiploic vessel and the submucosal vessels of the jejunum two weeks after the operation and the anastomosis was completed six weeks after the operation. The communicating blood vessels transformed themselves into a "fork" shape.

Angiography↗
PubMed2000

Cardiac alpha-actin in smooth muscle cells: detection in umbilical cord vessels and in atherosclerotic lesions.

Phenotypic modulation of smooth muscle cells (SMC) is a key event during the development of atherosclerotic and restenotic lesions. During this process, the composition of the cytoskeleton is substantially altered, with changes predominantly in actin expression reflecting a shift from smooth muscle alpha-actin to the non-muscle beta-isoform. We now demonstrate that yet another actin isoform, cardiac alpha-actin, is synthesized, de novo, in SMC of various atherosclerotic lesions. Using a highly specific monoclonal antibody against cardiac alpha-actin, we analyzed and compared the accumulation of this actin isoform in diverse SMC by immunofluorescence microscopy and immunoblotting. As expected, cardiac alpha-actin was present in human myocardium but not in healthy SMC of adult aorta, coronary arteries, trabeculae of the spleen, colon, stomach or skeletal muscle. Interestingly, the presence of cardiac alpha-actin was detected in umbilical cord vessels, human myometrium, in atherosclerotic coronary lesions and atherosclerotic lesions from peripheral vascular disease. The distribution of cardiac alpha-actin often paralleled that of cytokeratins 8 and 18, intermediate filament proteins typically found in dedifferentiated SMC. Taken together, the data presented here illustrate the expression of cardiac alpha-actin to be limited to either fetal vessels or those vessels or tissue having suffered damage or atrophy, outside its 'native' environment in the heart. The demonstration of cardiac alpha-actin in SMC of umbilical cord vessels and in atherosclerotic lesions but not in apparently healthy vessels supports the notion that SMC in atherosclerotic lesions exhibit a dedifferentiated phenotype.

Actins↗
PubMed2006

Localisation of lymphatic vessels and vascular endothelial growth factors-C and -D in human and mouse skeletal muscle with immunohistochemistry.

The present study was aimed to localise lymphatic vessels and their growth factors in human and mouse skeletal muscle with immunohistochemistry and specific antibodies (VEGFR-3, LYVE-1, VEGF-C and VEGF-D). The largest lymphatic vessels were found in perimysial connective tissue next to the arteries and veins, as has been shown earlier with electron microscopy. As a new finding, we also found small LYVE-1 positive vessels in the capillary bed between muscle fibres. These vessels were located next to CD31 positive blood capillaries and were of the same size, but fewer in number. In addition, we described the localisation of the two main lymphangiogenic growth factor proteins, vascular endothelial growth factor-C and -D. Both proteins were expressed in skeletal muscle at mRNA and protein levels. VEGF-D was located under the sarcolemma in some of the muscle fibres, in the endothelia of larger blood vessels and in fibroblasts. VEGF-C protein was localised to the nerves and muscle spindles, to fibroblasts and surrounding connective tissue, but was not found in muscle fibres or endothelial cells. Our results are the first to suggest the presence of lymphatic capillaries throughout the skeletal muscle, and to present the localisation of VEGF-C and -D in the muscles.

Animals↗
PubMed2006

Distributional characteristics of lymphatic vessels in normal human nasal mucosa and sinus mucosa.

An immunohistochemical staining technique with the D2-40 antibody was undertaken to examine the functional and morphological features of lymphatic networks in tissue sections and whole-mount preparations of normal nasal mucosa and ethmoid sinus mucosa. In normal nasal mucosa, most lymphatic vessels were found in the superficial mucosa beneath the epithelial layer. Some of these vessels were dilated, whereas others were compressed and had a slit-like lumen. Whole-mount preparations revealed the extent of lymphatic vessels in normal ethmoid sinus mucosa. A network of lymphatic vessels was mainly found in the subepithelial layer, where lymphatic vessels represented rich networks, possessing antler-like branches and typical blind ends. However, these lymphatic networks were not arranged in the form of lymphangion chains, with each lymphangion consisting of a contractile compartment and valve. Thus, recognition of the distinctive features of the lymphatic network in normal nasal and sinus mucosa might aid investigations of lymphatic involvement in sinonasal diseases, such as rhinitis, sinusitis, and malignancy.

Adult↗
PubMed1997

Fine structure and distribution of lymphatic vessels in the human dental pulp: a study using an enzyme-histochemical method.

The existence of lymphatic vessels in the human dental pulp and their distribution were established by light and electron microscopy using an enzyme-histochemical method. The distinction between lymphatic and blood vessels was made by light microscopy on cryostat sections of undecalcified and decalcified teeth using 5'-nucleotidase(5'-Nase)-alkaline phosphatase double staining. On the tissue surface, 5'-Nase-positive lymphatic vessels were highlighted with good contrast and resolution by backscattered electron imaging using scanning electron microscopy. By transmission electron microscopy, dense granular precipitations resulting from the 5'-Nase reaction were seen on the luminal surface of the lymphatic endothelial cells as well as in the area at the basal side, but were absent in the blood vessels. These lymphatic vessels were more numerous in the central part than in the peripheral odontoblastic layer.

5'-Nucleotidase↗
PubMed2001

Initial results with an electrothermal bipolar vessel sealer.

BACKGROUND: An electrothermal bipolar vessel sealer (EBVS; Ligasure, Valleylab, Boulder, CO, USA) was developed as an alternative to suture ligatures, hemoclips, staplers, and ultrasonic coagulators for ligating vessels and tissue bundles. The EBVS seals vessels up to 7 mm in diameter by denaturing collagen and elastin within the vessel wall and surrounding connective tissue. This study is the first to determine the clinical efficacy and safety of this instrument and delineate its potential timesavings in both experimental (animal) and clinical scenarios. METHODS: A prospective review of the author's clinical experience with the EBVS in laparoscopic and open operations from October 1998 to March 2000 was performed. In addition, five Yorkshire domestic pigs underwent 150-cm small intestine resections (n = 10) using the EBVS (n = 5) and suture ligatures (n = 5). Measurements included time to complete intestinal resection, the number of applications per minute for each method, and the presence of postapplication bleeding. Statistical analysis was performed using Student's t-test. RESULTS: The EBVS was used in 98 cases (46 laparoscopic and 52 open) with a mean of 43 applications (range, 10-150 applications) per case. The operations included 53 colon and/or small bowel resections (54.1%), 24 fundoplications (24.5%), 12 gastric resections (12.2%), 3 splenectomies, 2 pancreatectomies, 1 adrenalectomy, 1 bilateral salpingo-oopherectomy, 1 pancreatic cyst-jejunostomy, and 1 vagotomy with gastrojejunostomy. In all these cases, the EBVS was intended to be the only means of vessel ligation. An alternative ligation technique was required for bleeding in only 13 (0.3%) of more than 4,200 applications of the EBVS. No postoperative hemorrhagic complications occurred. There was an estimated mean reduction in operative time of 39 min per open procedure, and a mean prolongation in operative time of 8 min per laparoscopic procedure when the EBVS was used in lieu of suture ligatures, hemoclips, staplers, or ultrasonic coagulators. In the animal model, the mean time for completion of the intestinal resection was 251.9 s for the EBVS and 702.0 s for ligatures (p < 0.001). The mean number of applications per minute was 7.6 for the EBVS and 1.8 for ligatures (p < 0.001). No postapplication bleeding was seen. CONCLUSIONS: Initial clinical results from the use of EBVS in laparoscopic and open procedures demonstrate it to be safe and effective, reducing operative time in open procedures. Suture ligatures, ties, hemoclips, and other ligating techniques were used rarely (0.3%) after an application of the EBVS. In an experimental animal model, the EBVS was significantly faster and more efficient (more applications per minute) than ligatures for intestinal resection.

Animals↗
PubMed1998

Sutureless repair of major intracranial vessels with the Sundt clip-graft: technical note.

Major intracranial vessels can be damaged during tumor resection. With the availability of refined microvascular techniques, direct repair or by-pass of the damaged segment is possible. These methods, however, often require temporary occlusion of the offending vessel, can result in a less than optimal angiographic result, and are difficult to perform in a deep field. Additionally, in some patients direct repair or by-pass is not feasible because of the friability of the vessel or as a result of the large size of the tear. In these cases the Sundt clip-graft represents a valid adjunct to the armamentarium of the surgeon. Over the years, it has been used by the senior author in five patients where vascular injury occurred during the removal of brain tumors (3 meningiomas, one pituitary adenoma, and one low-grade glioma). In this report we illustrate our most recent experience with this ingenious tool. A 22-year-old man underwent resection of a recurrent left temporal lobe low-grade glioma. During resection of the tumor, a tear occurred in a branch of the middle cerebral artery. The tear was repaired using a Sundt clip-graft. A post-operative angiogram, performed five days later, showed patency of the vessel with no evidence of wall irregularities. Described 30 years age to be used primarily in aneurysm surgery, the Sundt clip-graft provides an excellent, too often forgotten, sutureless method of repairing intracranial vessels damaged during tumor removal.

Adult↗
PubMed1986

Treating avulsed vessels with a temporary balloon buckle.

We treated nine patients with avulsed retinal vessels by first expanding a balloon in the parabulbar space to buckle the vessel temporarily and then applying a laser beam to the avulsed segment. In three patients the avulsed vessel was an artery and in six it was a vein. The avulsion was the only abnormality in three patients; in six it was combined with a retinal break, which was accompanied by a detachment in five. The balloon brought the avulsed portion of the vessel into contact with the retina and the pigment epithelium and made it receptive to laser coagulation. Flow in the vessel could be slowed or stopped while the patient was undergoing laser treatment by further expanding the balloon.

Evaluation Studies as Topic↗
PubMed1988

Twin vessels in von Hippel-Lindau disease.

We examined ten patients from three families with von Hippel-Lindau disease and 26 of their at-risk relatives for the presence of twin vessels, defined as a paired retinal arteriole and venule that are separated by less than the diameter of one venule and extend for a distance of more than one disk diameter. They were compared with 36 age- and sex-matched controls. Of the 36 subjects in the study group, 23 had twin vessels compared with two controls (P less than 10(-6). Of the ten patients, nine (14 eyes) had twin vessels; no twin vessels were found in their controls (P = 5.9 x 10(-5)). Fourteen at-risk relatives and two of their controls had twin vessels (P = 9.4 x 10(-4)).

Adult↗
PubMed1993

A blood vessel model based on velocity profiles.

A simple model of pressure-flow relationship in blood vessels was developed. The calculation of the model components was based on velocity profiles in the vessels. The flat velocity profile in the entrance of the vessel was considered. By using mean pressure over the cross-section and assuming a polynomial approximation of the velocity profile, it is shown that the resistance of a vessel segment increases with increased flatness of the velocity profile. Moreover, the analysis provides a means to calculate the resistance of a vessel segment based on the shape of the velocity profiles in that segment. The analysis shows that the inertance element of the segment is not affected by the shape of the velocity profile.

Animals↗