Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BLOOD VESSELS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1999

Enhancement of nitroglycerin induced blood vessel relaxation in chronic renal failure model rats.

This study was designed to investigate the alternation of blood vessel relaxation in chronic renal failure (CRF) induced by adenine or partial-nephrectomy. The aorta was employed as the blood vessel material. CRF aorta relaxation in both adenine and partial nephrectomy induced rats increased when treated with glyceryl trinitrate (GTN). In the CRF animals, cGMP levels increased with the severity of CRF status. Aorta cytosolic glutathione S-transferase micro (GSTmicro) activity and enzyme contents increased with CRF. The effect of GTN on aortic vasorelaxation in both CRF statuses completely disappeared by the treatment with sodium nitoprusside. The effects of GTN were observed equally in both adenine- and partial nephrectomy-induced CRF rats. We concluded that alterations of aortic vasorelaxation by GTN in adenine- and partial nephrectomy-induced renal failure rats were caused by the enhancement of nitrogen monoxide production on the aortic blood vessel mediated by the induced GSTmicro in the aorta. This GSTmicro induction is peculiar to CRF since different CRF induction procedures produce the same results.

Adenine↗
PubMed1983

Effect of cold on the blood vessel wall.

The effect of cold has been studied on isolated canine and human blood vessels. These have led to the following conclusions concerning the phenomenon of the hunting reaction seen in human extremities on their exposure to severe cold. (1) On exposure to cold there is a marked increase in the affinity of the postjunctional alpha-adrenoceptors for norepinephrine. This results in a powerful constriction of the blood vessels and a cessation of blood flow to the distal tissue. As the temperature of the tissues rapidly falls, sympathetic nerve conduction is interrupted and vasodilatation occurs, due to the cessation of norepinephrine release and the depressor action of cold on the contractile machinery. The resultant return of blood flow rewarms the tissue, nerve conduction is reestablished, and this combined with the increased affinity of the alpha-adrenoceptors for norepinephrine leads to renewed vasoconstriction. Repetition of this cycle could result in the hunting reaction. (2) There appears to be a difference between the cutaneous artery and vein, in that the latter remains constricted at lower temperatures. (3) Preliminary experiments suggest that the response of the human cutaneous vein to cold is qualitatively similar to the dog vein, although some quantitative differences are present.

Animals↗
PubMed2003

Abnormalities of basement membrane on blood vessels and endothelial sprouts in tumors.

Often described as incomplete or absent, the basement membrane of blood vessels in tumors has attracted renewed attention as a source of angiogenic and anti-angiogenic molecules, site of growth factor binding, participant in angiogenesis, and potential target in cancer therapy. This study evaluated the composition, extent, and structural integrity of the basement membrane on blood vessels in three mouse tumor models: spontaneous RIP-Tag2 pancreatic islet tumors, MCa-IV mammary carcinomas, and Lewis lung carcinomas. Tumor vessels were identified by immunohistochemical staining for the endothelial cell markers CD31, endoglin (CD105), vascular endothelial growth factor receptor-2, and integrin alpha5 (CD49e). Confocal microscopic studies revealed that basement membrane identified by type IV collagen immunoreactivity covered >99.9% of the surface of blood vessels in the three tumors, just as in normal pancreatic islets. Laminin, entactin/nidogen, and fibronectin immunoreactivities were similarly ubiquitous on tumor vessels. Holes in the basement membrane, found by analyzing 1- micro m confocal optical sections, were <2.5 micro m in diameter and involved only 0.03% of the vessel surface. Despite the extensive vessel coverage, the basement membrane had conspicuous structural abnormalities, including a loose association with endothelial cells and pericytes, broad extensions away from the vessel wall, and multiple layers visible by electron microscopy. Type IV collagen-immunoreactive sleeves were also present on endothelial sprouts, supporting the idea that basement membrane is present where sprouts grow and regress. These findings indicate that basement membrane covers most tumor vessels but has profound structural abnormalities, consistent with the dynamic nature of endothelial cells and pericytes in tumors.

Animals↗
PubMed1984

Role of mosquito saliva in blood vessel location.

In order to ascribe a blood feeding function to the saliva of mosquitoes, we determined whether this secretion may limit the initial probing phase of biting behaviour. The probing of hosts was indeed prolonged when the salivary ducts were severed, but this prolongation was absent when mosquitoes were fed on an artificial meal contained beneath a membrane. In vitro, turbidometric assays demonstrated that saliva inhibits the ADP- and collagen-mediated aggregation of platelets. ATP and ADP were hydrolysed by saliva, and this apyrase activity explains, in part, the observed effect upon platelets. We conclude that the saliva of mosquitoes functions by facilitating location of blood vessels.

Adenosine Diphosphate↗
PubMed1991

Effects of alpha,beta-methylene ATP on resistance and capacitance blood vessels of the cat intestinal circulation; a comparison with other vasoconstrictor agents and sympathetic nerve stimulation.

The autoperfused intestinal circulation of pentobarbitone anaesthetized cats was used to study the effects of alpha,beta-methylene ATP (1-100 micrograms i.a.) on pre-capillary resistance vessels and post-capillary capacitance (venous) blood vessels in comparison with other vasoconstrictor agents (also given i.a.) and the effects of sympathetic nerve stimulation (0.25-16 Hz). All cats were treated with atropine and propranolol. alpha,beta-Methylene ATP, noradrenaline and sympathetic nerve stimulation all caused dose- or frequency-dependent constriction of both resistance and capacitance vessels. alpha,beta-Methylene ATP was particularly active on capacitance vessels causing a greater constriction than either noradrenaline or sympathetic nerve stimulation. In comparison, angiotensin II and vasopressin caused a selective constriction of resistance vessels and prostaglandin F2 alpha a selective constriction of capacitance vessels. The results demonstrate that functional P2x purinoceptors are present on both arterial and venous blood vessels of the cat intestinal circulation.

Adenosine Triphosphate↗
PubMed1998

Regulation of new blood vessel growth into ischemic skeletal muscle.

PURPOSE: In a rabbit model, transposition of a muscle pedicle flap to an ischemic hind limb has been shown to result in the development of new blood vessels that connect the arterial circulation of the flap to the circulation of the limb. The hypothesis that exogenous recombinant basic fibroblast growth factor (bFGF) would enhance the development of this new blood supply was examined and the regulation of bFGF in this process was investigated. METHODS: The right common iliac artery was ligated in 12 male New Zealand white rabbits. An abdominal wall muscle flap based on the left inferior epigastric artery was transposed to the right thigh. bFGF in phosphate-buffered saline (PBS) at 3 ng/h (n = 6), or PBS alone (n = 6), was infused for 7 days via mini-osmotic pumps with an infusion catheter positioned at the flap-muscle interface. The flap-muscle interface was immunostained with anti-alpha-actin antibody to determine blood vessel density (number of vessels/mm) and with anti-bFGF antibody to evaluate bFGF distribution. RNA was isolated from these sections, and polymerase chain reaction (PCR) was used to examine endogenous bFGF messenger RNA (mRNA) expression. RESULTS: Blood vessel density was significantly increased in animals receiving exogenous bFGF (22. 0 +/- 10.6 vessels/mm vs. 10.7 +/- 8.8 vessels/mm, P =.009). In the controls, neovessels were arranged in clusters with endogenous bFGF concentrated around these clusters. In bFGF-treated animals, vessels were diffusely scattered throughout the flap-limb interface, corresponding to the distribution pattern of infused bFGF. There was no difference in bFGF mRNA expression between the control and the bFGF-treated groups. CONCLUSION: Exogenous bFGF infusion significantly augmented new blood vessel development at the flap-limb interface. Endogenous bFGF was up-regulated around the newly developed microvessels in control animals, and vessel growth correlated with the diffuse distribution of exogenous bFGF, implicating bFGF as an important factor in angiogenesis. Exogenous bFGF did not affect bFGF mRNA expression, suggesting that the regulation of bFGF is not under autocrine control.

Animals↗
PubMedDate not supplied

The muscarinic receptor subtypes in human blood vessels.

Acetylcholine (ACh) may induce the relaxation and the contraction of human blood vessels. These effects involve the activation of muscarinic receptors located on endothelial or smooth muscle cells. In humans and animals, five subtypes of muscarinic receptors (M1-M5) have been identified. In the particular case of human blood vessels, the M3 subtype seems to be prevalent on endothelial cells as well as on smooth muscle cells. However, the M1 subtype may be specific for the pulmonary vascular endothelium. In contrast, the M4 subtype has not been described in human vessels. These conclusions are, however, based on a limited number of studies and further work is needed in this area of research. Although muscarinic receptors may not be the only receptors involved in hypertension, the development of specific agonists for M1 receptors may be useful to counteract any elevation of blood pressure in the pulmonary circulation.

Acetylcholine↗
PubMed1992

Endothelium-derived relaxing factor in brain blood vessels is not nitric oxide.

BACKGROUND: The endothelium-derived relaxing factor that mediates the actions of acetylcholine is now most frequently identified as nitric oxide. Nitric oxide is believed to have numerous important regulating actions in neurons, blood vessels, and several other biological systems. SUMMARY OF REVIEW: The literature concerning tissue other than cerebral blood vessels supports the conclusion that the endothelium-derived relaxing factor for acetylcholine is either nitric oxide or a compound formed from and containing nitric oxide (for example, a nitrosothiol). However, papers can be found indicating that this endothelium-derived mediator is not nitric oxide. In brain blood vessels the evidence is strongly against the conclusion that nitric oxide is the endothelium-derived mediator for acetylcholine. If this mediator is formed from nitric oxide, either in brain vessels or in other vessels, no data are available delineating how this synthesis is regulated or whether and where nitric oxide leaves the nitroso compound to initiate dilation. Indeed, cerebrovascular data now cast doubt on the commonly held belief that nitrosovasodilators regulate vascular tone by giving off nitric oxide to vascular smooth muscle. CONCLUSIONS: In brain blood vessels the chemical identity of the endothelium-derived relaxing factor mediating the action of acetylcholine is unknown, but this relaxing factor does not appear to be nitric oxide. If the mediator contains nitric oxide, as is probably the case, the means by which it activates vascular guanylate cyclase and/or produces dilation is unknown. Since this relaxing factor inhibits platelet adhesion/aggregation in cerebral vessels as well as relaxing these vessels, the chemical identification of this relaxing factor and the elucidation of its mode of action are extremely important to our understanding and control of cerebrovascular phenomena in health and disease.

Acetylcholine↗
PubMed1978

Three-dimensional architecture of blood vessels of tendons demonstrated by corrosion casts.

Three-dimensional observation of the microcirculation of the tendon was readily and clearly demonstrated by preparing methyl methacrylate casts and observing them under the scanning electron microscope. In the muscles blood vessels made a network like a ladder surrounding every muscle fibre. The fibrous digital sheath had blood vessels made in a fine meshed cylinder. By microdissection of the vessels of the sheath the blood vessels of the vinculae and tendons were observed stereoscopically in relation to the peritendinous tissues. The casting method contributes to better understanding of vascular architecture of tendons.

Animals↗
PubMed1994

Applications for cryopreserved blood vessels in pharmacological research.

The development of drugs in cardiovascular research involves in vitro studies that are generally performed on freshly isolated blood vessels. Naturally, data obtained from human tissues would be the most accurate and predictable for human pharmacology. However, the main problems are that the supply of fresh human material is unpredictable and the tissue has a very short life span. Storage in physiologic salt solution at 4 degrees C, the most common practice to preserve isolated blood vessels, induces rapid and progressive changes of physiologic and functional properties within a few days. Cryopreservation of isolated blood vessels at -70 to -196 degrees C in a medium containing Me2SO offers the prospect of virtually infinite storage of the material with the only damage being that associated with the freezing and thawing process. Despite certain changes, such as reductions in contractile forces and endothelial functions, the main biochemical properties, uptake mechanisms, and affinities of most agonists and antagonists have been shown to be well preserved after cryopreservation. Hence, this technique offers clear potential for ensuring the supply of vascular material for pharmacological studies.

Animals↗
PubMed1993

Vascular endothelial growth factor receptor expression during embryogenesis and tissue repair suggests a role in endothelial differentiation and blood vessel growth.

Vascular endothelial growth factor (VEGF) is a polypeptide mitogen that stimulates the growth of endothelial cells in vitro and promotes the growth of blood vessels in vivo. We have recently shown that the fms-like receptor tyrosine kinase (flt) is a receptor for VEGF. Here we used in situ hybridization to show that, in adult mouse tissues, the pattern of flt expression was consistent with localization in endothelium. We also show that flt was expressed in endothelium during neovascularization of healing skin wounds and during early vascular development in mouse embryos. Moreover, flt was expressed in populations of embryonic cells from which endothelium is derived such as early yolk sac mesenchyme. The expression of flt in the endothelium of both developing and mature blood vessels suggests that VEGF might regulate endothelial differentiation, blood vessel growth, and vascular repair.

Animals↗
PubMed2002

[Intramural blood vessels in the AV segment of the human heart conduction system].

We have investigated the intramural blood vessels of the A-V segment in the conductive system of 20 human hearts using the method of light microscopy. The results of our study have shown that the A-V segment of the conductive heart muscles in human hearts has an abundant vascularisation. We have found the greatest density of the intramural net in the dorsal part of the A-V node; this density of blood vessels decreased toward the Hiss' bundle. After comparing these results with the earlier findings in the study of the intramural net in the S-A system we have found that A-V segment of the conductive heart system has a poorer blood supply in regard to S-A system. We have also found that the intramural net of blood vessels is weaker in the adjacent ventricular parts and in the interventricular septum. It cannot be said that there exists any surface vascular zone subepicardial, middle and deep sub-endocardiac--in the A-V segment of the conductive system of human heart.

Atrioventricular Node↗
PubMed1997

Role of nitric oxide and nitric oxide-independent relaxing factor in contraction and relaxation of rabbit blood vessels.

It has been shown that spontaneous release of nitric oxide (NO) from the vascular endothelium attenuates contractile responses of vascular smooth muscles to norepinephrine, and that acetylcholine-induced relaxation is mediated by the evoked release of NO and endothelium-derived hyperpolarizing factor. Since the involvement of these substances (or factors) in mechanical responses is heterogeneous among blood vessels, we have investigated the role of these substances in agonist-induced contraction and relaxation in 6 rabbit blood vessels. Vascular reactivity for the contractile response to norepinephrine was potentiated after removal of endothelium and by 100 microM N(G)-nitro-L-arginine (L-NA) but not by 80 nM-0.4 microM clotrimazole. This potentiation was most marked in the mesenteric artery among the blood vessels tested, suggesting that the basal release of NO reduced the contractile response of the vascular smooth muscle to norepinephrine in this artery. Acetylcholine-induced relaxation was abolished by removal of the endothelium and was attenuated by L-NA (1-100 microM) in all blood vessels. The attenuation by 100 microM L-NA was most obvious in aorta and vein and least in mesenteric resistance artery in which the acetylcholine-induced, L-NA-resistant relaxation was inhibited by 80 nM-0.4 microM clotrimazole. These results suggested that there is a regional difference in the degree of involvement of NO in acetylcholine-induced relaxation. In mesenteric resistance artery, the NO-independent, clotrimazole-sensitive factor, possibly hyperpolarizing factor may also contribute to the response to acetylcholine at high concentrations.

Acetylcholine↗
PubMed1976

Redistribution of surface anionic sites on the luminal front of blood vessel endothelium after interaction with polycationic ligand.

The ability of anionic groups on the luminal surface of blood vessels to redistribute by lateral migration under the influence of multivalent ligands was analyzed by electron microscopy, using cationized ferritin (CF). In vitro interaction of blood vessel segments with CF results in rapid aggregation of most anionic sites on the luminal fromt of the endothelium, followed by internalization or detachment of the CF patches, leaving most of the luminal surface devoid of anionic sites. Further incubation of such endothelial cells without CF results in regeneration of binding capacity for the polycationic label. Transport of CF, but not of native ferritin, across the endothelium by vesicle transport, followed by exocytosis of the interiorized CF clusters on the tissue front of the endothelium, was also observed. The possibility that such activities in the blood vessels in vivo may be associated with local changes in the normal distribution of the surface anionic sites as well as in accumulation of debris in the subendothelial layers of the vessels is suggested.

Animals↗
PubMed2001

A cytochemical method for visualising blood vessels selectively in semithin LR white sections.

Traditional cytochemical techniques for illustrating blood vessels are usually unsuitable for use in high resolution, 0.35 microm-thick LR White sections due to the thinness of the tissue and, if collagenous, high background staining. We report that a modification of the periodic acid-thiocarbohydrazide-silver proteinate-silver enhancement method (PATCH-SP-SE) selectively visualises, with low background, even the smallest blood vessels in semithin LR White sections of highly collagenous tissues such as human parietal peritoneum.

Acrylic Resins↗
PubMed1981

[Contact transducer for continuous measurement of blood vessel diameter].

A device for continuous measurement of the external diameter of blood vessels in situ is described. It is based on a cantilever type design. The capacitance principle is used for measuring the displacement of the sensing plate. The sensing plate has the natural frequency of 25 Hz, stiffness about 2. 10(-4) N/mm and exercises the nominal load of the order of 2. 10(-4) N on the arterial wall. The small load eliminates the measurement errors and promotes a successful study of blood vessels over 0.4 mm in diameter within a wide range of transmural pressure.

Animals↗
PubMed2004

[Effect of expression of platelet-derived growth factor B gene on blood vessel reconstruction after tissue engineering skin grafting].

OBJECTIVE: To study the effect of PDGF on dermal blood vessel reconstruction by transplanted tissue-engineering skin containing PDGF-B gene to rats. METHODS: The recombined eukaryotic expression vector, pcDNA3.1-hPDGF-B, was constructed and transfected into fibroblasts mediated by LipofectAMINE. Keratinocytes + acellular dermal matrix (group A), keratinocytes + acellular dermal matrix + fibroblasts (group B), keratinocytes + acellular dermal matrix + fibroblasts with PDGF gene (group C) were recombined respectively, then transplanted them to rat dorsum and evaluated the reconstruction of blood vessels in the dermis after 2, 4, 6 week postoperation. RESULTS: In 2-4 weeks after skin grafting the vascularization rate in group C was higher than that of group B and group A. The vascularization rates in all groups had no significant differences in six weeks (P > 0.05). CONCLUSION: PDGF-B gene plays an important role in reconstruction of blood vessels in the dermis at early tissue-engineering skin grafting, which ensures the take of grafted tissue-engineering skin.

Acellular Dermis↗