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At least 55 records · Page 3Linked to original sources
PubMed1994

Preliminary analysis of the effects of blood vessel movement on blood flow patterns in the coronary arteries.

Blood flow patterns are believed to be involved in the formation and progression of arterial diseases. It is possible that the normal physiologic movement of blood vessels during the cardiac cycle affects blood flow patterns significantly. For example, the contraction of the heart in systole and subsequent relaxation in diastole create movements of the coronary arteries, as evidenced in real-time angiography. The effects of this movement on coronary artery flow patterns have never been previously analyzed. This work was undertaken to provide a preliminary estimate of the importance of the effects of such physiologic movements on blood flow patterns in the coronary arteries. A Womersley-type solution was used to determine the effect of axial movement on the wall shear rate in a simplified model of the coronary arteries. The pulsatile pressure gradient was derived from previously published coronary artery flow waveforms. The axial movement function was obtained from a three-dimensional reconstruction of a biplanar coronary angiogram. Significant changes in wall shear rate were noted when the movement was taken into account. The maximum and minimum wall shear rates were 10 percent smaller and 107 percent larger in magnitude respectively, and the Oscillatory Shear Index (OSI) was doubled. Most of the changes in wall shear rate were observed in systole, when the pressure gradient is minimal and the movement is strongest. The results indicate that blood vessel movement during the cardiac cycle has a significant effect on hemodynamic phenomena which have been associated with the development of atherosclerosis.

Arteriosclerosis↗
PubMed1991

Heterogeneity among ovarian blood vessels: endogenous hepatic lipase is concentrated in blood vessels of rat corpora lutea.

We used indirect immunofluorescence and immunogold light microscopy to examine the distribution of hepatic lipase, an enzyme involved in lipoprotein metabolism, in ovaries of gonadotropin-treated immature rats. Antibodies utilized were rabbit anti-rat hepatic lipase IgG, anti-rat von Willebrand factor (VWF, an endothelial cell marker), and goat anti-rabbit IgG conjugated to gold particles or rhodamine. Immunoreagents were applied to fresh frozen sections of unfixed ovary or liver (positive control) or were delivered to ovaries by vascular perfusion before fixation in situ and silver-enhancement of sections. Appropriate controls verified that the immunolocalizations were specific. Immunofluorescence implied that luteal but not stromal blood vessels of ovaries were positive for hepatic lipase, whereas luteal and stromal blood vessels bore VWF. The improved morphology gained by perfusing ovaries with antibodies allowed precise localization of the enzyme. Hepatic lipase was concentrated within thin-walled vessels of corpora lutea but not those of stroma in ovaries at the time of peak steroidogenic activity. Quantification of hepatic lipase-labeled vessels in stromal and luteal compartments confirmed our visual impression. Many images suggested that stromal vessels lacking hepatic lipase gained this enzyme upon contact with luteal tissue. Perfusion of ovaries with cationized ferritin labeled all ovarian vessels equally well, ruling out the possibility that the observed distribution of hepatic lipase was artifactual. These findings demonstrate that ovarian blood vessels are heterogeneous for hepatic lipase. Moreover, they imply that luteal tissue, perhaps luteal cells, may influence expression of hepatic lipase binding sites by endothelial cells.

Animals↗
PubMed2006

Antiangiogenic therapy decreases integrin expression in normalized tumor blood vessels.

Tumor blood vessels normalized by antiangiogenic therapy may provide improved delivery of chemotherapeutic agents during a window of time but it is unknown how protein expression in tumor vascular endothelial cells changes. We evaluated the distribution of RGD-4C phage, which binds alpha(v)beta(3), alpha(v)beta(5), and alpha(5)beta(1) integrins on tumor blood vessels before and after antiangiogenic therapy. Unlike the control phage, fd-tet, RGD-4C phage homed to vascular endothelial cells in spontaneous tumors in RIP-Tag2 transgenic mice in a dose-dependent fashion. The distribution of phage was similar to alpha(v)beta(3) and alpha(5)beta(1) integrin expression. Blood vessels that survived treatment with AG-013736, a small molecule inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptors, had only 4% as much binding of RGD-4C phage compared with vessels in untreated tumors. Cellular distribution of RGD-4C phage in surviving tumor vessels matched the alpha(5)beta(1) integrin expression. The reduction in integrin expression on tumor vessels after antiangiogenic therapy raises the possibility that integrin-targeted delivery of diagnostics or therapeutics may be compromised. Efficacious delivery of drugs may benefit from identification by in vivo phage display of targeting peptides that bind to tumor blood vessels normalized by antiangiogenic agents.

Adenoma, Islet Cell↗
PubMed1979

[Histochemical and ultrastructural studies of the innervation of the lymph-vessel and blood-vessel wall. 1. Adrenergic innervation].

The adrenergic innervation of the lymph vascular wall was studied by means of the Falck fluorescence histochemical tecnique and electron microscopy with Tranzer and Richards' histochemical tecnique. The lymph vessels wall, compared with that of blood vessels, shows very few adrenergic nerve fibers located in the adventitia outside the smooth muscle cells. The possible role of the nervous system in the motor control of the lymph vessels is discussed.

Adrenergic Fibers↗
PubMed1989

Embryonic origins and assembly of blood vessels.

Embryonic blood vessels develop in two ways: angiogenesis, which is growth by budding, branching, and elongation of existing vessels, and in situ formation of endothelial vesicles that coalesce with elongating vessels. It is assumed that the former is more prevalent, with the latter restricted to vessels that form near the endoderm:mesoderm interface. Neither the relative contributions of each of these processes in the formation of specific blood vessels nor the origins of precursors (angioblasts) of these intraembryonic endothelial populations are known. Antibodies that recognize quail endothelial cells can be used to follow the movements and differentiation of endothelial cell precursors after the transplantation of putative precursor populations from quail into chick embryos. Using this method, it has been shown that all intraembryonic mesodermal tissues, except the prechordal plate, contain angiogenic precursors. After transplantation some angioblasts move in all directions away from the site of implantation, invading surrounding mesenchyme and contributing to the formation of arteries, veins, and capillaries in a wide area. Although it is clear that these invasive angioblasts, which behave unlike any other embryonic mesenchymal cell type, are found throughout the embryo, it is not known whether they represent a unique endothelial cell type in mature blood vessels. Irrespective of their original location in the donor embryo, transplanted angioblasts will form vascular channels that are appropriate for the tissues surrounding their site of implantation. These results indicate that the control over vascular assembly resides within the connective-tissue-forming mesenchyme of the embryo.

Animals↗
PubMed1997

The degree of nonlinearity and anisotropy of blood vessel elasticity.

Blood vessel elasticity is important to physiology and clinical problems involving surgery, angioplasty, tissue remodeling, and tissue engineering. Nonlinearity in blood vessel elasticity in vivo is important to the formation of solitons in arterial pulse waves. It is well known that the stress-strain relationship of the blood vessel is nonlinear in general, but a controversy exists on how nonlinear it is in the physiological range. Another controversy is whether the vessel wall is biaxially isotropic. New data on canine aorta were obtained from a biaxial testing machine over a large range of finite strains referred to the zero-stress state. A new pseudo strain energy function is used to examine these questions critically. The stress-strain relationship derived from this function represents the sum of a linear stress-strain relationship and a definitely nonlinear relationship. This relationship fits the experimental data very well. With this strain energy function, we can define a parameter called the degree of nonlinearity, which represents the fraction of the nonlinear strain energy in the total strain energy per unit volume. We found that for the canine aorta, the degree of nonlinearity varies from 5% to 30%, depending on the magnitude of the strains in the physiological range. In the case of canine pulmonary artery in the arch region, Debes and Fung [Debes, J. C. & Fung, Y. C.(1995) Am. J. Physiol. 269, H433-H442] have shown that the linear regime of the stress-strain relationship extends from the zero-stress state to the homeostatic state and beyond. Both vessels, however, are anisotropic in both the linear and nonlinear regimes.

Animals↗
PubMed1979

[Histochemical and ultrastructural studies of the innervation of the lymph-vessel and blood-vessel wall. II. Cholinergic innervation].

Using the Acetylcholinesterase (AChE) tecnique applied to light and electron microscopy, was observed that the lymph vascular wall shows very few and inconstant AChE-positive fibers. The cholinergic fibers run prevalently longitudinal in the perivascular connective tissue, only brief segments show a loose network. The results are discussed and compared with blood vessels innervation.

Animals↗
PubMed1983

Differences in blood vessels between species: relation to differences in blood vessels of varying type within the same species.

1. Major differences in physiological and pharmacological responsiveness may be observed between blood vessels that differ either in anatomical type or in that they serve different organs or tissues. 2. The intrinsic properties of the vascular smooth muscle appears to differ little between species. No important differences in noradrenergic innervation have been observed, but major differences may exist in neural dilator systems. A few differences have been demonstrated that can be attributed to variations in the receptor population. No clear differences in local humoral mechanisms are known. There is, however, an insufficient number of strictly comparable studies in different species and it is likely that more differences will be found as our knowledge of vascular responsiveness is extended.

Animals↗
PubMed1991

[Significance of blood vessel invasion in gastric carcinoma--prediction of liver metastases from the blood vessel invasion in the primary tumors].

This study was conducted to elucidate the factors related with liver metastases, to clarify the significance of blood vessel invasion and then to predict liver metastases from these findings. Patients examined were 102 cases which underwent gastrectomy and were followed-up for more than 5 years or until death at our department. Two new staining methods were applied in this study; Victoria blue + hematoxylin eosin double staining for elastic fiber and Factor VIII related antigen for vascular endothelium. Significant differences in qualitative frequency of blood vessel invasion, the number of lymph node metastases, and the depth of invasion were found in those patients with liver metastases, as compared with 5 year survivors. Quantitative analysis of blood vessel invasion revealed significant importance of blood vessel invasions in the submucosa, in the forms of complete thrombus, wall invasion and partial thrombus, in the diameters of 0.01-0.1 mm and 0.1-1.0 mm. Applying discrimination coefficients of linear discrimination analysis, prediction of liver metastases was possible with 81.8% sensitivity, 85.3% specificity, and 83.6% accuracy. Liver metastases can be predicted from the qualitative and quantitative analyses of blood vessel invasion in the primary tumors by elastic fiber staining.

Gastric Mucosa↗