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At least 595 records · Page 33Linked to original sources
PubMed1982

Further studies on acoustic impedance of major bovine blood vessel walls.

Data on ultrasound velocity and specific impedance of major bovine blood vessel walls are compared to structural protein content measured by hydroxypoline assay as well as total solid tissue content of these tissues. Results indicate that acoustic velocity in these tissues is determined largely by the collagen and elastin contents of the tissues. However, acoustic impedance, which is the product of density and velocity, shows a stronger dependence on the total tissue content, suggesting that other solid tissues, in particular, muscle in blood vessel walls, may also play a significant role in the determination of acoustic impedance.

Adipose Tissue↗
PubMed1991

Strongly succinate dehydrogenase-reactive blood vessels in muscles from patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes.

Intramuscular blood vessels were examined with succinate dehydrogenase stain in skeletal muscle biopsy specimens from 6 patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Almost all arteries had large granular deposits with high succinate dehydrogenase activity in their walls. Electron microscopic examination of serial frozen sections of these biopsies showed that the smooth muscle cells of the strongly succinate dehydrogenase-reactive blood vessels contained markedly proliferated mitochondria, characteristic of patients with MELAS. The presence of strongly succinate dehydrogenase-reactive blood vessels in muscle biopsy specimens provides an important clue toward understanding the underlying pathogenetic mechanism in patients with MELAS as well as another approach to the diagnosis of this disorder.

Acidosis, Lactic↗
PubMed1996

Light distributions in a port wine stain model containing multiple cylindrical and curved blood vessels.

BACKGROUND AND OBJECTIVES: Knowledge of the light distribution in skin tissue is important for the understanding, prediction, and improvement of the clinical results in laser treatment of port wine stains (PWS). The objective of this study is to improve modelling of PWS treated by laser using an improved and more realistic PWS model. STUDY DESIGN/MATERIALS AND METHODS: Light distributions are calculated by the Monte Carlo method for various PWS blood vessel configurations, such as single and multiple vessels oriented horizontally, curved vessels, and "vertically" oriented vessels. Various vessel sizes and wavelengths are used. RESULTS: Our modelling confirms the concept of selective photothermolysis; 577nm laser light gives maximal deposited energy at the top side of the blood vessels closest to the skin surface and 585nm gives a more uniform energy distribution in the vessel. In the distribution of deposited energy multiple vessels mutually influence each other, because of "shadowing" of diffuse light. CONCLUSION: Modelling PWS laser treatments with multiple vessels confirms the need for successive treatments of vessels layer by layer. The use of different wavelengths affects the local deposited energy profiles in the blood vessels. It predicts that the significance of 585nm laser light lies in the uniform energy distribution in the vessels rather than in gain in energy deposition with depth. The calculated light distributions provide a more realistic input for modelling thermal damage effects in PWS laser treatment and modelling of the epidermal response in thermal imaging of the PWS blood vessel structure.

Blood Vessels↗
PubMed1989

Immunohistochemical observation on neuropeptides around the blood vessel in feline dental pulp.

Recent advances in immunohistochemistry have revealed the distribution of various neuropeptides in several mammalian dental pulps. These neuropeptides are substance P, neurokinin A, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and neuropeptide Y. Nerve fibers showing immunoreactivity for these neuropeptides are mainly localized around the pulpal vessels, but some are apart from the blood vessel. The distribution of substance P-, neurokinin A-, and calcitonin gene-related peptide-containing nerve fibers is very similar; it appears that these three neuropeptides may be contained in the same nerve fibers. Denervation experiments indicate that substance P-, neurokinin A- and calcitonin gene-related peptide-containing nerve fibers originate from the trigeminal ganglion and that neuropeptide Y-containing nerve fibers come from the superior cervical ganglion. However, the exact origin of vasoactive intestinal polypeptide-containing fibers still remains unknown. These immunohistochemical data indicate that neuropeptides localized around the blood vessel may play a significant role in the regulation of the blood flow in the dental pulp.

Animals↗
PubMed1985

Morphometric analysis of retinal blood vessels in retinopathia diabetica.

A quantitative investigation of the retinal blood vessels was carried out in 80 diabetics and 20 metabolically healthy controls of the same age and sex distribution. The blood vessels were isolated by trypsinization, stained with PAS, and analyzed by light microscopy. After 1-5 years' duration of diabetes mellitus, capillary lesions in the ocular fundus can be seen microscopically in the slides, but not with a stereomicroscope. In the retinae of persons with normal carbohydrate metabolism, capillary defects were found to a far lesser extent; they were also always localized in the periphery of the retina, whereas the diabetic lesions were localized in the retinal center. In the diabetics, both capillary lesions (e.g., loss of pericytes) and damage of the retinal neurons occurred nearly simultaneously and with the same retinal localization. This suggests that the capillary lesions are not the cause of neuronal degeneration but that both events are caused by the same mechanisms of pathogenesis.

Adult↗
PubMed1992

The expression of human chorionic gonadotropin/luteinizing hormone receptors in human endometrial and myometrial blood vessels.

hCG/human LH (hLH) receptors have recently been found in human endometrial and myometrial cells and uterine vasculature. The present study was undertaken to further corroborate the immunocytochemical evidence for the presence of vascular receptors. Northern blot and in situ hybridization analyses have revealed that human uterus contains a major 4.3-kilobase and a minor 2.6-kilobase hCG/hLH receptor mRNA transcript and that these transcripts are present in part in endometrial and myometrial vascular smooth muscle cells and vascular endothelial cells. Immunoblot and immunocytochemical analyses have revealed that human uterus also contains a single immunoreactive receptor protein, and that this receptor protein in part is present in endometrial and myometrial vascular smooth muscle and vascular endothelium. The expression of receptor mRNA and/or immunoreactive receptor protein was higher in myometrial than in endometrial blood vessels, and higher in vessels of both uterine compartments from the secretory compared to proliferative phase, postmenopause, or pregnancy. The blood vessels in omentum, broad ligament, and parametrium did not immunostain for hCG/hLH receptors. A blood vessel seen traversing through parametrium immunostained for the receptor protein only after it entered the myometrium. The blood vessels in nontarget tissues did not immunostain, whereas those in some target tissues, but not all of them, immunostained for the receptor protein. In summary, the present study demonstrates for the first time that human endometrial and myometrial vascular smooth muscle and endothelium express hCG/hLH receptor mRNA and immunoreactive receptor protein. These findings suggest that hCG/hLH may directly regulate blood flow in human uterus and other target tissues. The reproductive state dependency of uterine vascular receptors suggests that these receptors are probably regulated by other reproductive hormones.

Blood Vessels↗
PubMed2006

Role of hematopoietic lineage cells as accessory components in blood vessel formation.

In adults, the vasculature is normally quiescent, due to the dominant influence of endogenous angiogenesis inhibitors over angiogenic stimuli. However, blood vessels in adults retain the capacity for brisk initiation of angiogenesis, the growth of new vessels from pre-existing vessels, during tissue repair and in numerous diseases, including inflammation and cancer. Because of the role of angiogenesis in tumor growth, many new cancer therapies are being conducted against tumor angiogenesis. It is thought that these anti-angiogenic therapies destroy the tumor vessels, thereby depriving the tumor of oxygen and nutrients. Therefore, a better understanding of the molecular mechanisms in the process of sprouting angiogenesis may lead to more effective therapies not only for cancer but also for diseases involving abnormal vasculature. It is widely believed that after birth, endothelial cells (EC) in new blood vessels are derived from resident EC of pre-existing vessels. However, evidence is now emerging that cells derived from the bone marrow may also contribute to postnatal angiogenesis. Most studies have focused initially on the contribution of endothelial progenitor cells in this process. However, we have proposed a concept in which cells of the hematopoietic lineage are mobilized and then entrapped in peripheral tissues, where they function as accessory cells that promote the sprouting of resident EC by releasing angiogenic signals. Most recently we found that hematopoietic cells play major roles in tumor angiogenesis by initiating sprouting angiogenesis and also in maturation of blood vessels in the fibrous cap of tumors. Therefore, manipulating these entrapment signals may offer therapeutic opportunities to stimulate or inhibit angiogenesis.

Angiotensin I↗
PubMed1989

SEM characterization of a cellular layer separating blood vessels from endoderm in the quail embryo.

The associations between the developing blood vessels and both endoderm and splanchnic mesoderm in quail embryos at stages 9-11 were examined by using scanning electron microscopy. Embryos were pinned ventral-side up on agar plates and the endoderm was surgically removed prior to fixation and dehydration. This procedure exposes a netlike layer of cells closely apposed to the ventral surface of paraxial mesoderm and all visible blood vessels; we are calling this the subvascular layer. Development of this layer proceeds rostral-to-caudal, and lateral-to-medial, with the earliest stages of formation being visible over the unsegmented paraxial mesoderm of the segmental plate. The subvascular layer increases markedly in density slightly medial to the innermost boundary of the intraembryonic vascular plexus. Cells of this layer eventually establish a continuous sheet beneath the lateral plate and paraxial mesoderm and the notochord. With maturation, the cells of the subvascular layer approach confluence. The spatial and temporal patterns of development of the embryonic vascular tissues and the subvascular layer are closely correlated, suggesting a possible role for the subvascular layer in normal embryonic vascular development.

Animals↗
PubMed1997

The matrix metalloproteinase RASI-1 is expressed in synovial blood vessels of a rheumatoid arthritis patient.

RASI-1 is a novel matrix metalloproteinase which we isolated from an expression cDNA library representing the mRNA of an inflamed synovium obtained from a patient with rheumatoid arthritis (RA). To investigate the involvement of RASI-1 in the pathology of RA, we examined synovial specimens from RA patients with antibodies directed against an unique RASI-1-derived peptide. In comparison to interstitial collagenase, gelatinase A and B, and stromelysin 1, the RASI-1 expression in the RA-synovium is located mainly in the tunica media of blood vessel walls and its synovial localization is not as ubiquitous as that of other MMPs. The tissue inhibitor of metalloproteinases (TIMP-1), although also widely expressed in the synovium, exhibits strong colocalization with RASI-1 in blood vessel walls. While RASI-1 is expressed in blood vessels of the inflamed synovium of an RA patient, its expression was not found in control synovial specimens from patients with luxation and arthrosis. However, RASI-1 expression can also be found in non-inflamed blood vessels of uterine ligaments and skin. RASI-1, although its function and substrates are unknown, could be involved in processes such as neovascularization and angiogenesis or lymphocyte extravasation and thus may participate in joint tissue destruction during RA.

Amino Acid Sequence↗
PubMed1989

Direct cannulation of myocardial blood vessels without interfering with regional blood flow distribution, resting blood flow, or reactive hyperemia.

An in vivo technique of directly cannulating coronary arteries and veins for sampling blood and measuring hemodynamic parameters is described. The cannulation procedure was evaluated for its effects on regional myocardial blood flow (RMBF), transmural RMBF distribution, and reactive hyperemia. In a group of ten dogs, RMBF was measured by using radionuclide microspheres. Values for left anterior descending (LAD) perfusion zone (with catheter) and circumflex (CX) zone (no catheter) did not differ significantly (119 +/- 14 mL/min/100 g v 123 +/- 14 mL/min/100 g, respectively). Likewise, endocardial-to-epicardial RMBF ratio was similar for the two areas (0.99 +/- 0.06 and 1.04 +/- 0.06, respectively). In five dogs, aortic and left ventricular pressures agreed closely with the LAD coronary artery pressure measured with the described catheter system. Arterial flow during rest and reactive hyperemia was measured in five additional dogs by using electromagnetic flow probes placed around the LAD and CX coronary arteries. During both rest and reactive hyperemia, flow was greater in the CX than in the LAD (65.46 +/- 4.12 and 169.62 +/- 9.04 in the CX v 30.24 +/- 0.78 and 102.28 +/- 5.38 in the LAD; P less than 0.05 for both); however, the percentage change from rest to reactive hyperemia was similar for both vessels. In each perfusion zone, flow during rest and reactive hyperemia and the percentage change were not affected by cannulation. The effects of an infusion of adenosine (20 to 40 micrograms/min) into the pulmonary artery with and without the LAD coronary catheters (artery and vein) were tested in six other dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1999

Simultaneous irradiation and imaging of blood vessels during pulsed laser delivery.

BACKGROUND AND OBJECTIVE: Simultaneous irradiation and viewing of 10-120 microm cutaneous blood vessels were performed to investigate the effects of 2-micros 577-nm dye laser pulses. STUDY DESIGN/MATERIALS AND METHODS: A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability ("threshold") radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage. RESULTS: A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10-30 microm in diameter, but not for larger vessels. For vessels over 60 microm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results. CONCLUSION: These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation.

Angiography↗
PubMed1998

Innervation of blood vessels in the rat incisor pulp: a scanning electron microscopic and immunoelectron microscopic study.

Although two types of nerve endings have been proposed to innervate blood vessels in the dental pulp, the precise innervation pattern is not well understood. This is mainly due to the lack of information regarding the positional relationships of nerve fibers with blood vessels at the electron microscopic level. The rat incisor pulp was investigated by scanning electron microscopy (SEM) after connective tissue digestion and by transmission electron microscopy after immunohistochemical localization with polyclonal anti-PGP 9.5 antibody. SEM specimens revealed that unmyelinated nerve fibers passed through the tunica adventitia of the blood vessel in the center of the pulp and that these fibers then entered the tunica media of the smaller arterioles. The nerve fibers divided into many collaterals, and these terminated on the surface of smooth muscle cells and endothelial cells. The fibers extended toward smaller vessels. The terminal fibers then reached the subodontoblastic capillary plexus and terminated on pericytes, while the odontoblastic capillary plexus had no direct innervation. In the pulpal venules, nerve fibers were located adjacent to the pericytes and endothelial cells, and they extended toward postcapillary venules. The same results were confirmed by immunoelectron microscopy. The present study demonstrated that in the rat incisor pulp the microvasculature as well as larger vessels were directly innervated by free nerve endings, suggesting that the local regulation of blood flow could take place not only at larger vessels but also at the level of the microvasculature in this tissue.

Animals↗
PubMed2003

Hepatic bipolar radiofrequency ablation creates coagulation zones close to blood vessels: a finite element study.

Radiofrequency (RF) ablation has become an important means of treatment of non-resectable primary and metastatic liver tumours. Recurrence of treated tumours is associated with cancer cell survival next to blood vessels. The paper examines the performance of classical monopolar, and two configurations of bipolar, RF ablation using a LeVeen ten-prong catheter. Finite element method models of monopolar and bipolar configurations were created at 5 mm distance from a vessel of the size of a typical portal vein (10 mm diameter). In one bipolar configuration, the probes were oriented in the same axial direction (asymmetric configuration); in the second bipolar configuration, the two probes were facing each other (symmetric configuration). The distribution of temperature and current density was analysed for three different flow conditions: normal flow, reduced flow due to portal hypertension and high flow. For normal flow, the distance between the formed coagulation zone and the blood vessel was 1.8 mm for monopolar, 1 mm for asymmetric bipolar, and 0.2 mm for symmetric bipolar, configurations. Symmetric bipolar RF ablation creates coagulation zones significantly closer to blood vessels compared with monopolar RF ablation. This may reduce tumour cell survival next to blood vessels and reduce recurrence rates.

Catheter Ablation↗
PubMedDate not supplied

Increased smooth muscle actin expression from bone marrow stromal cells under retinoic acid treatment: an attempt for autologous blood vessel tissue engineering.

Vascular replacement in vital organs is sometimes necessary for human life for example because of atherosclerosis. Blood vessel tissue engineering is applied for autologous transplantations to avoid graft rejections. Stem cells are used for blood vessel tissue engineering because they are the origin of smooth muscle cells, endothelial cells and fibroblasts. This paper shows that bone marrow stromal cells (BMSCs) can be induced to differentiate into the early stage of smooth muscle cells by using 0.01 microM retinoic acid. The differentiation of BMSCs to smooth muscle cells was detected by the expression of smooth muscle alpha actin (SM alpha-actin), the earliest smooth muscle cell marker. The SM alpha-actin marker expression was demonstrated using indirect immunofluorescence technique and Western blot analysis. The induction of BMSC to form early stages of smooth muscle cells in this study is appropriate for blood vessel tissue engineering because the early stage smooth muscle cells may be stimulated to develop vascular walls with endothelial cells using a co-culture system.

Actins↗
PubMed1989

[Electrochemical phenomena in autoregulatory reactions of the blood vessels].

Some physiological mechanisms being in the basis of autoregulatory reactions of blood vessels have been studied. It has been found that the rise in the difference of the potentials of electrochemical origin between inner and exterior vessel surfaces during blood movement facilitates to increase the vessel myogenic reaction at the intravascular pressure rise, to intensify spontaneous bioelectrical activity of smooth muscle cells and hydration of a vascular wall. These phenomena are reproduced by the application to a vessel a constant potential commensurable with one rising during blood movement.

Animals↗
PubMed1986

Susceptibility of endothelial cells derived from different blood vessels to common viruses.

We examined whether endothelial cells derived from different blood vessels vary in their susceptibility to viral infection. Five common viral pathogens of humans (herpes simplex 1, measles, mumps, echo 9, and coxsackie B4 viruses) were evaluated for growth in endothelial cells derived from bovine fetal pulmonary artery, thoracic aorta, and vena cava. All five viruses replicated in each type of endothelial cell. There were apparent differences in the quantities of measles and mumps viruses produced in pulmonary artery endothelium compared with thoracic aorta and vena cava when endothelial cells were obtained from different animals. However, when pulmonary artery endothelial cells were compared with vena cava cells from the same animal, growth of each virus was similar in the two cell types. Four of the viruses replicated in the various endothelial cells without producing appreciable changes in cell morphology. These results indicate that endothelial cells from different blood vessels are equally susceptible to the human viruses evaluated, and that viral replication can occur without major alterations in cell morphology. Endothelial cells could serve as permissive cells permitting viruses to leave the circulation and initiate infection in adjacent tissues, including subendothelial smooth muscle cells.

Animals↗
PubMed1997

Measurement of strain exerted on blood vessel walls by double-quantum-filtered 2H NMR.

In this study 2H double quantum-filtered (DQF) NMR spectroscopy of water molecules inside the blood vessel wall was used to monitor structural changes after the application of strain. This method was applied to a variety of bovine large blood vessels, including aorta, coronary artery, carotid artery, and vena cava. Inducing strain in coronary arteries by inflating them by air or water revealed dramatic changes in the 2H DQF spectral lineshapes. Uniaxial extensions of longitudinal and circumferential strips led to distinct spectral responses for the different blood vessels. While the spectral lineshapes for the coronary and the carotid arteries were very sensitive to longitudinal strain, they were not affected by circumferential stretching. For the aorta there were no changes in the lineshape upon strain. For the vena cava a large effect of strain was found that was independent of the choice of elongation axis. The effect of elongation on the spectra was assigned to the outer layer, the adventitia, whereas spectral lineshapes that originated from inner layers, media and intima, were almost insensitive to strain. Angular dependence experiments proved the presence of macroscopic order in the strained state superimposed on a broad distribution of the local directors. Our results demonstrate the sensitivity of 2H DQF NMR as a probe for dynamic processes occurring on the microscopic scale in a molecular network.

Animals↗