Note: This page contains sample records for the topic blood vessel branching from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

reg6 is required for branching morphogenesis during blood vessel regeneration in zebrafish caudal fins  

Microsoft Academic Search

Postnatal neovascularization is essential for wound healing, cancer progression, and many other physiological functions. However, its genetic mechanism is largely unknown. In this report, we study neovascularization in regenerating adult zebrafish fins using transgenic fish that express EGFP in blood vessel endothelial cells. We first describe the morphogenesis of regenerating vessels in wild-type animals and then the phenotypic analysis of

Cheng-chen Huang; Nathan D Lawson; Brant M Weinstein; Stephen L Johnson

2003-01-01

2

Spatially restricted patterning cues provided by heparin-binding VEGF-A control blood vessel branching morphogenesis  

PubMed Central

Branching morphogenesis in the mammalian lung and Drosophila trachea relies on the precise localization of secreted modulators of epithelial growth to select branch sites and direct branch elongation, but the intercellular signals that control blood vessel branching have not been previously identified. We found that VEGF120/120 mouse embryos, engineered to express solely an isoform of VEGF-A that lacks heparin-binding, and therefore extracellular matrix interaction domains, exhibited a specific decrease in capillary branch formation. This defect was not caused by isoform-specific differences in stimulating endothelial cell proliferation or by impaired isoform-specific signaling through the Nrp1 receptor. Rather, changes in the extracellular localization of VEGF-A in heparin-binding mutant embryos resulted in an altered distribution of endothelial cells within the growing vasculature. Instead of being recruited into additional branches, nascent endothelial cells were preferentially integrated within existing vessels to increase lumen caliber. The disruption of the normal VEGF-A concentration gradient also impaired the directed extension of endothelial cell filopodia, suggesting that heparin-binding VEGF-A isoforms normally provide spatially restricted stimulatory cues that polarize and thereby guide sprouting endothelial cells to initiate vascular branch formation. Consistent with this idea, we found opposing defects in embryos harboring only a heparin-binding isoform of VEGF-A, including excess endothelial filopodia and abnormally thin vessel branches in ectopic sites. We conclude that differential VEGF-A isoform localization in the extracellular space provides a control point for regulating vascular branching pattern.

Ruhrberg, Christiana; Gerhardt, Holger; Golding, Matthew; Watson, Rose; Ioannidou, Sofia; Fujisawa, Hajime; Betsholtz, Christer; Shima, David T.

2002-01-01

3

What guides early embryonic blood vessel formation?  

Microsoft Academic Search

Survival of vertebrate embryos depends on their ability to assemble a correctly patterned, integrated network of blood vessels to supply oxygen and nutrients to developing tis- sues. The arrangement of larger caliber intraem- bryonic vessels, specification of arterial-venous identity, and proper placement of major branch points and arterial-venous connections are all precisely determined. A number of recent studies in both

Brant M. Weinstein

1999-01-01

4

Atherosclerotic involvement of coronary branch vessels.  

PubMed

The atherosclerotic involvement of coronary branch vessels (first diagonal, first septal, posterior descending, left and right marginals, conus and the vessels supplying the conduction system) was investigated in 450 apparently healthy subjects aged 11-55 years who died of accidental causes. In subjects 35-55 years old, 1 out of every 3 persons with atherosclerotic plaques in the major coronary arteries also had atherosclerotic plaques in coronary branch vessels; the respective relation for fatty streaks was 1 out of every 12 subjects, for intimal necrotic areas 1 out of every 7 subjects and for incorporated microthrombi 1 out of every 9 subjects. One out of every 3 subjects 51-55 years old had more than 50% lumen reduction in the undistended major coronary arteries, compared to 1 out of every 6 subjects in undistended coronary branch vessels. A small subgroup (8.2%) showed more severe stenotic lesions in coronary branch vessels than in coronary major arteries. The atherosclerotic plaques of coronary branch vessels appeared as 'underdeveloped', lacking a thick fibrohyaline cap, a large detritus cavity, abundant lipid deposition, cholesterol crystals, basal vascularization, intraplaque hemorrhage, ulceration, calcification, occlusive thrombosis. On the other hand the stenotic character of these plaques was often severe (more than 75% lumen reduction). The questionable value of the estimation of the ischemic significance of a coronary stenosis in the absence of available data on the development of a compensatory collateral circulation is discussed. PMID:3730044

Velican, C; Velican, D

1986-06-01

5

Imaging of aortic and branch vessel trauma.  

PubMed

Although infrequently encountered in busy trauma centers, injuries to the aorta and branch vessels remain an important cause of trauma-related mortality. Advances in the diagnosis and management of these injuries have led to more accurate and timely imaging, and improved patient outcomes. Despite these advances, several challenges in evaluating the severely injured trauma patient remain. This review provides an overview of current concepts in the imaging of aortic and branch vessel injuries, and provides pointers to improve detection and interpretation of more challenging injuries. PMID:22099489

Gunn, Martin L

2011-10-22

6

Blood flow reprograms lymphatic vessels to blood vessels.  

PubMed

Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate-specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow. PMID:22622036

Chen, Chiu-Yu; Bertozzi, Cara; Zou, Zhiying; Yuan, Lijun; Lee, John S; Lu, MinMin; Stachelek, Stan J; Srinivasan, Sathish; Guo, Lili; Vicente, Andres; Vincente, Andres; Mericko, Patricia; Levy, Robert J; Makinen, Taija; Oliver, Guillermo; Kahn, Mark L

2012-05-24

7

Blood vessel rupture by cavitation  

Microsoft Academic Search

Cavitation is thought to be one mechanism for vessel rupture during shock wave lithotripsy treatment. However, just how cavitation\\u000a induces vessel rupture remains unknown. In this work, a high-speed photomicrography system was set up to directly observe\\u000a the dynamics of bubbles inside blood vessels in ex vivo rat mesenteries. Vascular rupture correlating to observed bubble dynamics\\u000a were examined by imaging

Hong Chen; Andrew A. Brayman; Michael R. Bailey; Thomas J. Matula

2010-01-01

8

Tubulogenesis during blood vessel formation  

PubMed Central

The ability to form and maintain a functional system of contiguous hollow tubes is a critical feature of vascular endothelial cells (ECs). Lumen formation, or tubulogenesis, occurs in blood vessels during both vasculogenesis and angiogenesis in the embryo. Formation of vascular lumens takes place prior to the establishment of blood flow and to vascular remodeling which results in a characteristic hierarchical vessel organization. While epithelial lumen formation has received intense attention in past decades, more recent work has only just begun to elucidate the mechanisms controlling the initiation and morphogenesis of endothelial lumens. Studies using in vitro and in vivo models, including zebrafish and mammals, are beginning to paint an emerging picture of how blood vessels establish their characteristic morphology and become patent. In this chapter, we review and discuss the molecular and cellular mechanisms driving the formation of vascular tubes, primarily in vivo, and we compare and contrast proposed models for blood vessel lumen formation.

Xu, Ke; Cleaver, Ondine

2011-01-01

9

Blood Flow Changes Coincide with Cellular Rearrangements during Blood Vessel Pruning in Zebrafish Embryos  

PubMed Central

After the initial formation of a highly branched vascular plexus, blood vessel pruning generates a hierarchically structured network with improved flow characteristics. We report here on the cellular events that occur during the pruning of a defined blood vessel in the eye of developing zebrafish embryos. Time-lapse imaging reveals that the connection of a new blood vessel sprout with a previously perfused multicellular endothelial tube leads to the formation of a branched, Y-shaped structure. Subsequently, endothelial cells in parts of the previously perfused branch rearrange from a multicellular into a unicellular tube, followed by blood vessel detachment. This process is accompanied by endothelial cell death. Finally, we show that differences in blood flow between neighboring vessels are important for the completion of the pruning process. Our data suggest that flow induced changes in tubular architecture ensure proper blood vessel pruning.

Kochhan, Eva; Lenard, Anna; Ellertsdottir, Elin; Herwig, Lukas; Affolter, Markus; Belting, Heinz-Georg; Siekmann, Arndt F.

2013-01-01

10

Blood Flow Changes Coincide with Cellular Rearrangements during Blood Vessel Pruning in Zebrafish Embryos.  

PubMed

After the initial formation of a highly branched vascular plexus, blood vessel pruning generates a hierarchically structured network with improved flow characteristics. We report here on the cellular events that occur during the pruning of a defined blood vessel in the eye of developing zebrafish embryos. Time-lapse imaging reveals that the connection of a new blood vessel sprout with a previously perfused multicellular endothelial tube leads to the formation of a branched, Y-shaped structure. Subsequently, endothelial cells in parts of the previously perfused branch rearrange from a multicellular into a unicellular tube, followed by blood vessel detachment. This process is accompanied by endothelial cell death. Finally, we show that differences in blood flow between neighboring vessels are important for the completion of the pruning process. Our data suggest that flow induced changes in tubular architecture ensure proper blood vessel pruning. PMID:24146748

Kochhan, Eva; Lenard, Anna; Ellertsdottir, Elin; Herwig, Lukas; Affolter, Markus; Belting, Heinz-Georg; Siekmann, Arndt F

2013-10-11

11

Tubulogenesis during blood vessel formation  

Microsoft Academic Search

The ability to form and maintain a functional system of contiguous hollow tubes is a critical feature of vascular endothelial cells (ECs). Lumen formation, or tubulogenesis, occurs in blood vessels during both vasculogenesis and angiogenesis in the embryo. Formation of vascular lumens takes place prior to the establishment of blood flow and to vascular remodeling which results in a characteristic

Ke Xu; Ondine Cleaver

12

Disrupting tumour blood vessels  

Microsoft Academic Search

Low-molecular-weight vascular-disrupting agents (VDAs) cause a pronounced shutdown in blood flow to solid tumours, resulting in extensive tumour-cell necrosis, while they leave the blood flow in normal tissues relatively intact. The largest group of VDAs is the tubulin-binding combretastatins, several of which are now being tested in clinical trials. DMXAA (5,6-dimethylxanthenone-4-acetic acid) — one of a structurally distinct group of

Chryso Kanthou; Bruce C. Baguley; Gillian M. Tozer

2005-01-01

13

Nerve Cell Signposts in the Blood Vessel Roadmap  

Microsoft Academic Search

he vasculature and the nervous system both form extensively branched networks in the vertebrate body, incorporate into very different tissue environments, and establish connections over long distances. Although there are many obvious morphological and functional differences between blood vessels and nerve fibers, one should not ignore striking conceptual similarities in the assembly of these networks through guided growth and branching

Ralf H. Adams

2010-01-01

14

Airway and blood vessel interaction during lung development  

PubMed Central

In the adult lung the pulmonary arteries run alongside the airways and the pulmonary veins show a similar branching pattern to the arteries, though separated from them. During early fetal development the airways act as a template for pulmonary blood vessel development in that the vessels form by vasculogenesis around the branching airways. In later lung development the capillary bed is essential for alveolar formation. This paper reviews evidence for the interaction of the airways and blood vessels in both normal and abnormal lung development.

Hislop, Alison A

2002-01-01

15

Blood Vessels of the Future  

NSDL National Science Digital Library

Forty-ninth monthly installment of our "What A Year!" website project, introducing life science breakthroughs to middle and high school students and their teachers. The use of bioengineered blood vessels in place of grafts could reduce the number of surgeries needed by dialysis patients and increase the effectiveness of each treatment. It could also simplify coronary artery bypass graft surgery by eliminating the need to find a usable artery somewhere else in the patient.

2011-06-03

16

Dynamic mechanisms of blood vessel growth  

PubMed Central

The formation of a polygonal configuration of proto-blood-vessels from initially dispersed cells is the first step in the development of the circulatory system in vertebrates. This initial vascular network later expands to form new blood vessels, primarily via a sprouting mechanism. We review a range of recent results obtained with a Monte Carlo model of chemotactically migrating cells which can explain both de novo blood vessel growth and aspects of blood vessel sprouting. We propose that the initial network forms via a percolation-like instability depending on cell shape, or through an alternative contact-inhibition of motility mechanism which also reproduces aspects of sprouting blood vessel growth.

Merks, Roeland M H; Glazier, James A

2009-01-01

17

Application of morphological bit planes in retinal blood vessel extraction.  

PubMed

The appearance of the retinal blood vessels is an important diagnostic indicator of various clinical disorders of the eye and the body. Retinal blood vessels have been shown to provide evidence in terms of change in diameter, branching angles, or tortuosity, as a result of ophthalmic disease. This paper reports the development for an automated method for segmentation of blood vessels in retinal images. A unique combination of methods for retinal blood vessel skeleton detection and multidirectional morphological bit plane slicing is presented to extract the blood vessels from the color retinal images. The skeleton of main vessels is extracted by the application of directional differential operators and then evaluation of combination of derivative signs and average derivative values. Mathematical morphology has been materialized as a proficient technique for quantifying the retinal vasculature in ocular fundus images. A multidirectional top-hat operator with rotating structuring elements is used to emphasize the vessels in a particular direction, and information is extracted using bit plane slicing. An iterative region growing method is applied to integrate the main skeleton and the images resulting from bit plane slicing of vessel direction-dependent morphological filters. The approach is tested on two publicly available databases DRIVE and STARE. Average accuracy achieved by the proposed method is 0.9423 for both the databases with significant values of sensitivity and specificity also; the algorithm outperforms the second human observer in terms of precision of segmented vessel tree. PMID:22832895

Fraz, M M; Basit, A; Barman, S A

2013-04-01

18

The extracellular matrix of blood vessels.  

PubMed

Blood vessels are highly organized and complex structure, which are far more than simple tubes conducting the blood to almost any tissue of the body. They are able to autonomously regulate the blood flow, thus providing the tissues an optimal support of oxygen and nutrients and an efficient removal of waste products. In higher organisms, the blood vessel forms a closed circuit system, which additionally has the ability to seal itself in case of leakage as a result of injury. The blood vessel system does not only transport soluble substances, but also serves as "highway" system for leukocytes to patrol the body during the immunological surveillance and to reach the inflammation site quickly. In a complex interplay with the vascular wall, leukocytes are able to penetrate the blood vessel without any obvious leakage. Pathologically, tumor cells subvert the blood vessel system to disseminate from the primary tumor and colonize distant organs during metastasis. The extracellular matrix (ECM) of a blood vessel contributes substantially to the diverse functions of the blood vessel. First, the ECM constitutes the scaffold which keeps the histological structure of the vessel wall in shape but also bears the enormous and permanent mechanical forces levied on the vessel by the pulsatile blood flow in the arteries and by vasoconstriction, which regulates blood flow and pressure. The complex network of elastic fibers and tensile forces-bearing networks are well adapted to accomplish these mechanical tasks. Second, the ECM provides informational cues to the vascular cells, thus regulating their proliferation and differentiation. Third, ECM molecules can store, mask, present or sequester growth factors, thereby modulating their effects remarkably. Furthermore, several ECM molecules serve additional functions within the blood vessel. Their expression is altered in a spatial and temporal pattern during blood vessel formation and remodeling. In contrast to vasculogenesis during embryonic development, blood vessel shows a remarkably and life-long plasticity, which allows the formation and regeneration of new blood vessel even in adulthood. Both physiologically during wound healing and pathologically during tumor growth, the sprouting of new blood vessels during angiogenesis is an important process, in which the ECM takes a key role. PMID:19355976

Eble, Johannes A; Niland, Stephan

2009-01-01

19

Genetic Analysis of Blood Vessel Formation  

Microsoft Academic Search

Formation of new blood vessels is vital during embryogenesis, essential for reproduction and wound healing during adulthood, and required to rescue tissue during ischemia. Neovascularization may, however, also contribute to the pathogenesis of several disorders, including tumorigenesis, diabetic vasculopathy, and chronic inflammation. Initially, blood vessels form as endothelium-lined channels by in situ differentiation of endothelial cells. Subsequently, they sprout and

Peter Carmeliet; Désiré Collen

1997-01-01

20

Unsteady Flow in Stenotic Blood Vessels  

NASA Astrophysics Data System (ADS)

Recent studies show that many heart attacks and strokes occur from sudden rupture of partially occluding atherosclerotic plaque rather than total vessel occlusion. Our goal is to understand how the mechanical forces induced by blood flow on specific plaque deposits makes them vulnerable to rupture. Models of severely stenotic carotid bifurcations are created from MR images and grids generated for the flow domains. The three-dimensional, unsteady, incompressible Navier-Stokes equations in finite-volume form are solved numerically using physiological boundary conditions. During systole a high velocity jet forms at the stenotic throat in one of the branches, and a long recirculation zone is observed downstream of the plaque. During diastole the flow is more stagnant. The flow is highly three-dimensional and unsteady with chaotic streamlines. Whereas flow in healthy arteries is laminar, irregular geometries and sharp changes in vessel diameter of a severely stenotic artery significantly disrupt the flow, with consequences for shear and normal wall stresses at the wall, and important implications for plaque stability. Supported by NIH Grant HL61823

Rayz, Vitaliy L.; Devi Williamson, Shobha; Berger, Stanley A.; Saloner, David

2003-11-01

21

Blood Vessel Formation during Wound Healing.  

National Technical Information Service (NTIS)

This report summarizes a series of studies undertaken to determine if angiogenic molecules isolated from normal tissues and wound fluid could accelerate wound repair. Angiogenesis (new blood vessel formation) is a critical component of many normal and pat...

J. J. Castellot

1995-01-01

22

Are Type II (Branch Vessel) Endoleaks Really Benign?  

Microsoft Academic Search

  The natural history and clinical significance of type II or branch vessel endoleaks following endovascular aortic aneurysm\\u000a (AAA) repair remain unclear. Some investigators have suggested that these endoleaks have a benign course and outcome and that\\u000a they can be safely observed. The purpose of this study was to document the natural history and outcome of all type II endoleaks\\u000a that

Sonya N. Tuerff; Caron B. Rockman; Patrick J. Lamparello; Mark A. Adelman; Glenn R. Jacobowitz; Paul J. Gagne; Matthew M. Nalbandian; Jonathan Weiswasser; Ronnie Landis; Robert J. Rosen; Thomas S. Riles

2002-01-01

23

Blood flow and macromolecular transport in complex blood vessels.  

PubMed

Numerical simulations of pulsatile flows and macromolecular (such as LDL) transport in complex blood vessels, including the cerebral artery, are carried out using the FLUENT software. The hemodynamic factors such as axial velocity, secondary flow as well as LDL concentration distribution in the complex vessel are obtained. It is found that in the case of pulsatile flow, the LDL concentration is higher in the central region of the flow than on the wall. Under the precondition of impermeability, the numerical results indicate that the blood flow is quite complicated in complex blood vessel. The complex flow can reduce the LDL concentration on the vessel wall, which is helpful to prevent the concentration polarization. PMID:17767985

Hong, Jinxing; Wei, Lan; Fu, Ceji; Tan, Wenchang

2007-09-04

24

Blood velocity measurement in human conjunctival vessels  

PubMed Central

The bulbar conjunctiva is one of the few areas in which blood flow in the peripheral vasculature can be directly and noninvasively observed in the human. Although extensive literature exists describing morphological changes which correlate with a variety of systemic diseases in this vasculature, little quantitative data is available on hemodynamics in either normal or abnormal states. The hemodynamic data available are primarily subjective assessments of “low flow.” Approaches to place the subjective assessment on more quantitative grounds have usually been based on photographic techniques that have intrinsic inadequacies. The objective of the work reported here was to develop a system capable of providing sequential blood velocity data potentially useful for providing quantitative information on blood flow and its change in the microvessels of the human conjunctiva. The method that has evolved uses a standard Zeiss slit-lamp to image a subject's conjunctival vessels by using a 1-inch Newvicon TV camera with an electronic magnification of 2x. The video image is simultaneously recorded on a video tape recorder (VTR) to an overall system magnification of approximately 4 ?m/raster line. The data acquisition phase requires approximately 5 minutes of patient time, whereas the actual determination of blood velocity in individual vessels is done offline through a modification of the dual-slit videodensimetric method. Two independently controllable video cursors are placed axially over the vessel image with the VTR in the still-frame mode. For each consecutive video field, the position of two reference points on the vessel and the position of each cursor relative to these and to each other are encoded into a computer to track the moving image caused by normal eye movement. The computer then determines new cursor coordinates to ensure a constant position within the vessel. The electrical signals obtained for each cursor site and for each video field are cross-correlated to yield the average blood velocity over the sampled time interval. The system has been calibrated in vitro from 0.2 to 2.5 mm/sec, evaluated in experimental animals, and used to measure blood velocity (0.3 to 1.5 mm/sec) in human conjunctival venules with diameters ranging from 20 to 50 ?m. At this writing, blood velocity has been recorded during a period of about 3 months in the same vessel of several postmyocardial infarction patients. Thus, the method appears suitable for determining sequential changes in small vessel blood flow in patients over extended periods of time. Images

Mayrovitz, Harvey N.; Larnard, Donald; Duda, Gloria

1981-01-01

25

NO mediates mural cell recruitment and vessel morphogenesis in murine melanomas and tissue-engineered blood vessels  

PubMed Central

NO has been shown to mediate angiogenesis; however, its role in vessel morphogenesis and maturation is not known. Using intravital microscopy, histological analysis, ?–smooth muscle actin and chondroitin sulfate proteoglycan 4 staining, microsensor NO measurements, and an NO synthase (NOS) inhibitor, we found that NO mediates mural cell coverage as well as vessel branching and longitudinal extension but not the circumferential growth of blood vessels in B16 murine melanomas. NO-sensitive fluorescent probe 4,5-diaminofluorescein imaging, NOS immunostaining, and the use of NOS-deficient mice revealed that eNOS in vascular endothelial cells is the predominant source of NO and induces these effects. To further dissect the role of NO in mural cell recruitment and vascular morphogenesis, we performed a series of independent analyses. Transwell and under-agarose migration assays demonstrated that endothelial cell–derived NO induces directional migration of mural cell precursors toward endothelial cells. An in vivo tissue-engineered blood vessel model revealed that NO mediates endothelial–mural cell interaction prior to vessel perfusion and also induces recruitment of mural cells to angiogenic vessels, vessel branching, and longitudinal extension and subsequent stabilization of the vessels. These data indicate that endothelial cell–derived NO induces mural cell recruitment as well as subsequent morphogenesis and stabilization of angiogenic vessels.

Kashiwagi, Satoshi; Izumi, Yotaro; Gohongi, Takeshi; Demou, Zoe N.; Xu, Lei; Huang, Paul L.; Buerk, Donald G.; Munn, Lance L.; Jain, Rakesh K.; Fukumura, Dai

2005-01-01

26

Blood vessels as targets in tumor therapy  

PubMed Central

The landmark papers published by Judah Folkman in the early 1970s on tumor angiogenesis and therapeutic implications promoted the rapid development of a very dynamic field where basic scientists, oncologists, and pharmaceutical industry joined forces to determine the molecular mechanisms in blood vessel formation and find means to exploit this knowledge in suppressing tumor vascularization and growth. A wealth of information has been collected on angiogenic growth factors, and in 2004 the first specific blood vessel-targeted cancer therapy was introduced: a neutralizing antibody against vascular endothelial growth factor (VEGF). Now (2011) we know that suppression of tumor angiogenesis may be a double-edged sword and that the therapy needs to be further refined and individualized. This review describes the hallmarks of tumor vessels, how different angiogenic growth factors exert their function, and the perspectives for future development of anti-angiogenic therapy.

2012-01-01

27

A novel method for blood vessel detection from retinal images  

Microsoft Academic Search

BACKGROUND: The morphological changes of the retinal blood vessels in retinal images are important indicators for diseases like diabetes, hypertension and glaucoma. Thus the accurate segmentation of blood vessel is of diagnostic value. METHODS: In this paper, we present a novel method to segment retinal blood vessels to overcome the variations in contrast of large and thin vessels. This method

Lili Xu; Shuqian Luo

2010-01-01

28

Blackworms, Blood Vessel Pulsations and Drug Effects.  

ERIC Educational Resources Information Center

|Introduces the freshwater oligochaete worm, lumbriculus variegatus (common name: blackworms), an organism that is well suited for classroom study because of its closed circulatory system. Describes a set of simple, fast, noninvasive, and inexpensive methods for observing pulsations of the worm's dorsal blood vessels under baseline conditions, and…

Lesiuk, Nalena M.; Drewes, Charles D.

1999-01-01

29

Zinc oxide nanoflowers make new blood vessels  

NASA Astrophysics Data System (ADS)

It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role.It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role. Electronic supplementary information (ESI) available: See DOI: 10.1039/c2nr32369a

Barui, Ayan Kumar; Veeriah, Vimal; Mukherjee, Sudip; Manna, Joydeb; Patel, Ajay Kumar; Patra, Sujata; Pal, Krishnendu; Murali, Shruthi; Rana, Rohit K.; Chatterjee, Suvro; Patra, Chitta Ranjan

2012-11-01

30

Cellular flow in a small blood vessel  

NASA Astrophysics Data System (ADS)

In the tubes and vessels with diameters D < 8?m red blood cells organize into single-file trains. Simulations are used to investigate flow in a model blood vessel slightly larger than this, D = 11.3?m, for which the cells deviate from this single-file arrangement, deforming continuously and significantly. The effective viscosity of the flow is found to become shear-rate insensitive at higher shear rates (U/D > 50s-1) and to match experimental data. At lower shear rates (down to U/D = 3.7s-1), the effective viscosity increases by over 50 percent. The cell-free layer that forms along the vessel walls thickens with increasing shear rate and is the key factor governing the overall flow resistance. Cells near the vessel wall are on average inclined relative to the wall, as might be expected for a lubrication mechanism leading to its formation. Metrics are developed to quantify the kinematics in terms of the well-known tank-treading and tumbling behaviors often observed for isolated cells. These rates are found to scale with the velocity difference across the cell-rich core and are thus significantly slower than the overall shear rate in the flow.

Freund, Jonathan; Orescanin, Mara

2010-11-01

31

Effect of branchings on blood flow in the system of human coronary arteries.  

PubMed

In this work, we investigate the behavior of the pulsatile blood flow in the system of human coronary arteries. Blood is modeled as an incompressible non-Newtonian fluid. The transient phenomena of blood flow through the coronary system are simulated by solving the three dimensional unsteady state Navier-Stokes equations and continuity equation. Distributions of velocity, pressure and wall shear stresses are determined in the system under pulsatile conditions on the boundaries. Effect of branching vessel on the flow problem is investigated. The numerical results show that blood pressure in the system with branching vessels of coronary arteries is lower than the one in the system with no branch. The magnitude of wall shear stresses rises at the bifurcation. PMID:22229404

Wiwatanapataphee, Benchawan; Wu, Yong Hong; Siriapisith, Thanongchai; Nuntadilok, Buraskorn

2012-01-01

32

Photoacoustic removal of occlusions from blood vessels  

DOEpatents

Partial or total occlusions of fluid passages within the human body are removed by positioning an array of optical fibers in the passage and directing treatment radiation pulses along the fibers, one at a time, to generate a shock wave and hydrodynamics flows that strike and emulsify the occlusions. A preferred application is the removal of blood clots (thrombin and embolic) from small cerebral vessels to reverse the effects of an ischemic stroke. The operating parameters and techniques are chosen to minimize the amount of heating of the fragile cerebral vessel walls occurring during this photo acoustic treatment. One such technique is the optical monitoring of the existence of hydrodynamics flow generating vapor bubbles when they are expected to occur and stopping the heat generating pulses propagated along an optical fiber that is not generating such bubbles.

Visuri, Steven R. (Livermore, CA); Da Silva, Luiz B. (Danville, CA); Celliers, Peter M. (Berkeley, CA); London, Richard A. (Orinda, CA); Maitland, IV, Duncan J. (Lafayette, CA); Esch, Victor C. (San Francisco, CA)

2002-01-01

33

Method and device for supporting blood vessels during anastomosis  

DOEpatents

A device and method for preventing first and second severed blood vessels from collapsing during attachment to each other. The device comprises a dissolvable non-toxic stent that is sufficiently rigid to prevent the blood vessels from collapsing during anastomosis. The stent can be hollow or have passages to permit blood flow before it dissolves. A single stent can be inserted with an end in each of the two blood vessels or separate stents can be inserted into each blood vessel. The stent may include a therapeutically effective amount of a drug which is slowly released into the blood stream as the stent dissolves. 12 figs.

Doss, J.D.

1985-05-20

34

Assessment of Blood Vessel Mimics with Optical Coherence Tomography  

Microsoft Academic Search

Optical coherence tomography (OCT) is an imaging mo-dality that enables assessment of tissue structural characteristics. Studies have indicated that OCT is a useful method to assess both blood vessel morphology and the response of a vessel to a deployed stent. We evaluated the ability of OCT to visualize the cellular lining of a tissue-engineered blood vessel mimic (BVM) and the

Garret T. Bonnema; Kristen OHalloran Cardinal; James B. McNally; Stuart K. Williams; Jennifer K. Barton

2007-01-01

35

On the Adaptive Detection of Blood Vessels in Retinal Images  

Microsoft Academic Search

This paper proposes an automated blood vessel detection scheme based on adaptive contrast enhancement, feature extraction, and tracing. Feature extraction of small blood vessels is performed byusing the standard deviation of Gabor filter responses. Tracing of vessels is done via forward detection, bifurcation identification, and backward verification. Tests over twentyimages show that for normal images, the true positive rate (TPR)

Di Wu; Ming Zhang; Jyh-Charn Liu; Wendall Bauman

2006-01-01

36

Blood-vessel formation: Bridges that guide and unite  

Microsoft Academic Search

To form new blood vessels, the endothelial tip cells of two existing vessels come together by the process of anastomosis. But how do they find each other? Macrophages seem to provide a bridge and mediate their union.

Thomas Schmidt; Peter Carmeliet

2010-01-01

37

Distribution of Nitric Oxide Synthase in the Human Cerebral Blood Vessels and Brain Tissues  

Microsoft Academic Search

Summary: The distribution of nitric oxide synthase was investigated in human cerebral blood vessels and brain tissues. NADPH-diaphorase histochemistry, which is a marker for nitric oxide synthase in neurons and endothelial cells, revealed periadventitial nerve fibers in the arteries of the circle of Willis and their cortical branches, as well as the common carotid and subclavian arteries. The fibers were

Hidekazu Tomimoto; Masaki Nishimura; Toshihiko Suenaga; Sinichi Nakamura; Ichiro Akiguchi; Hideaki Wakita; Jun Kimura; Bernd Mayer

1994-01-01

38

Prolactin and blood vessels: a comparative endocrinology perspective.  

PubMed

The hormone prolactin (PRL), fundamental for lactation in mammals, is known to exert a wide diversity of actions in the various vertebrate groups. Blood vessels are surfacing as important PRL targets, contributing to these hormonal functions. PRL promotes the growth of new blood vessels (angiogenesis) and is proteolytically cleaved to vasoinhibins, a family of peptides (including 16-kDa PRL) with potent antiangiogenic and blood vessel regression effects. These opposing actions point to the regulation of the proteases responsible for PRL cleavage as an efficient way to balance blood vessel growth and involution. This review briefly summarizes the effects of PRL and vasoinhibins on blood vessels in mammals and discusses whether similar vascular actions could contribute to the effects of PRL on the development, growth, and reproduction of lower vertebrates. A comparative study in diverse species may lead to a better understanding of blood vessels as a driving force for the biological actions of PRL. PMID:22245261

Clapp, Carmen; Martínez de la Escalera, Lucía; Martínez de la Escalera, Gonzalo

2012-01-05

39

Unusual blood vessels in the cochlea of the squirrel monkey  

Microsoft Academic Search

Summary  Unusual blood vessels in the cochlea of the squirrel monkey are reported. The blood vessels in Reissner’s membrane and basilar membrane are occasionally found in the course of the experimental middle ear study.The blood vessel of Reissner’s membrane derives from a radiating arteriole in the upper spiral ligament and takes a straight course down to the inner surface of the

Fumihisa Hiraide; Tetsuzo Inouye

1980-01-01

40

Expression Sites of Colligin 2 in Glioma Blood Vessels  

PubMed Central

In a previous study using state-of-the-art proteomic techniques, we identified colligin 2 (HSP47) as a glioma blood vessel-specific protein. In the present study we precisely localized the expression of colligin 2 in the blood vessels of diffusely infiltrating gliomas and relate the expression to the distinct cellular components of the vessels by using multiple immunolabeling and confocal microscopy. We grouped the glioma blood vessels into morphological categories ranging from normal looking capillaries to vessels with hypertrophic and sclerotic changes. The expression patterns of various markers of endothelial and pericytic differentiation were correlated with the position of the cells in the vessels and the expression of colligin 2. We found that colligin 2 is expressed in all categories of glioma blood vessels in cells with endothelial and pericytic lineage. Expression of colligin 2 was also found in cells scattered around blood vessels and in few glial fibrillary acidic protein-positive cells within the blood vessels. There is overlap in the expression of colligin 2 and the collagens type I and IV for which colligin 2 is a chaperon. We conclude that colligin 2 is expressed in all cellular components of glioma blood vessels and may serve as a general marker for active angiogenesis.

Mustafa, Dana; van der Weiden, Marcel; Zheng, PingPin; Nigg, Alex; Luider, Theo M; Kros, Johan M

2010-01-01

41

Angle-preserving mappings for the visualization of multi-branched vessels  

Microsoft Academic Search

In this note, we employ a conformal mapping technique to flatten tubular structures with multi-branches for visualiza- tion of MRA and CT volumetric vessel imagery. This may be used for the study of possible vessel pathology or virtual colonscopy for polyp detection. The method is based on a discrete Laplace-Beltrami operator to flatten a tubular sur- face onto a planar

Lei Zhu; Steven Haker; Sylvain Bouix; Kaleem Siddiqi; Allen Tannenbaum

2002-01-01

42

Microvascular Architecture in a Mammary Carcinoma: Branching Patterns and Vessel Dimensions1  

Microsoft Academic Search

The objective of this work was to introduce a tumor vessel classification scheme and to provide the first quantitative measurements of vessel branching patterns and the related vascular dimensions in a mammary carcinoma. Mammary adenocarcinoma R3230AC tumors, grown in the rat ovarian tissue-isolated tumor preparation, were infused with Batson's No. 17 polymer and maintained at an intravascular pressure of 50

Thomas C. Skalak; Eva M. Sevick; Rakesh K. Jain

1991-01-01

43

The role of blood flow and microRNAs in blood vessel development.  

PubMed

The circulatory system is the first organ system that develops during embryogenesis, and is essential for embryo viability and survival. Crucial for developing a functional vasculature are the specification of arterial-venous identity in vessels and the formation of a hierarchical branched vascular network. Sprouting angiogenesis, intussusception, and flow driven remodeling events collectively contribute to establishing the vascular architecture. At the molecular level, arterial-venous identity and branching are regulated by genetically hardwired mechanisms involving Notch, vascular endothelial growth factor and neural guidance molecule signaling pathways, modulated by hemodynamic factors. MicroRNAs are small, non-coding RNAs that act as silencers to fine-tune the gene expression profile. MicroRNAs are known to influence cell fate decisions, and microRNA expression can be controlled by blood flow, thus placing microRNAs potentially at the center of the genetic cascades regulating vascular differentiation. In the present review, we summarize current progress regarding microRNA functions in blood vessel development with an emphasis on studies performed in zebrafish and mouse models. PMID:21858767

Liu, Dong; Krueger, Janna; Le Noble, Ferdinand

2011-01-01

44

Blood Vessel Segmentation from MRA Based on Boltzmann Theory  

Microsoft Academic Search

Segmentation is one of the most challenging problems in the field of medical image analysis, and blood vessels are especially difficult to extract. In this paper, we propose a novel method for segmentation of cerebral blood vessels from magnetic resonance angiography (MRA) images based on Boltzmann theory. The method is composed of three major steps: first, power-law transformation is applied

Shifeng Zhao; Mingquan Zhou; Li Dai; Yanlin Luo

2007-01-01

45

CCR Connections - Inflammation: Where Immune Cells and Blood Vessels Collide  

Cancer.gov

Model of hypoxia-induced retinopathy. The collapse of blood vessels in the eye results in a lack of oxygen delivery to the tissue. This hypoxic environment generates signals that cause abnormal blood vessel proliferation, which can be suppressed by angiogenesis inhibitors.

46

Imaging stented tissue engineered blood vessel mimics  

NASA Astrophysics Data System (ADS)

An ideal vascular stent design promotes a thin anti-thrombogenic cellular lining while avoiding restenosis. To assess the utility of their designs, stent manufactures often use destructive techniques such as scanning electron microscopy to measure the percentage of the stent covered with a cellular lining. In this study, we use a custom-built longitudinal/rotational scanning endoscope and determine the ability of optical coherence tomography (OCT) to quantify the percent cellular coverage of stented tissue engineered blood vessel mimics. Stents were deployed within twelve mimics after 14-days of development in bioreactors. OCT images were acquired within the bioreactor at several time points after the stent deployment. At 20-days post deployment, the mimics were fixed and imaged volumetrically with OCT. Matlab software was developed to automatically calculate the percent cellular coverage from the OCT images. Algorithm results were compared to similar measurements performed with bis-benzimide (BBI) fluorescence imaging and manually calculated percent coverage from three different observers of the OCT images. Progressive accumulation of cellular material on the stents could be visualized with OCT. For the volumetric images, the algorithm calculated percent cellular coverages ranging from 11 to 76%. Good agreement was found between the OCT-based measurements and the other techniques. On average, the algorithm differed less than 5% from the manual percent coverage calculations. OCT together with automated software can provide an accurate, non-destructive measurement of the percent cellular coverage of vascular stents.

Bonnema, Garret T.; Cardinal, Kristen O.; Williams, Stuart K.; Barton, Jennifer K.

2008-03-01

47

Silk fibroin microtubes for blood vessel engineering  

PubMed Central

Currently available synthetic grafts demonstrate moderate success at the macrovascular level, but fail at the microvascular scale (<6 mm inner diameter). We report on the development of silk fibroin microtubes for blood vessel repair with several advantages over existing scaffold materials/designs. These microtubes were prepared by dipping straight lengths of stainless steel wire into aqueous silk fibroin, where the addition of poly(ethylene oxide) (PEO) enabled control of microtube porosity. The microtube properties were characterized in terms of pore size, burst strength, protein permeability, enzymatic degradation, and cell migration. Low porosity microtubes demonstrated superior mechanical properties in terms of higher burst pressures, but displayed poor protein permeability; whereas higher porosity tubes had lower burst strengths but increased permeability and enhanced protein transport. The microtubes also exhibited cellular barrier functions as low porosity tubes prevented outward migration of GFP-transduced HUVECs, while the high porosity microtubes allowed a few cells per tube to migrate outward during perfusion. When combined with the biocompatible and suturability features of silk fibroin, these results suggest that silk microtubes, either implanted directly or preseeded with cells, are an attractive biomaterial for microvascular grafts.

Lovett, Michael L.; Cannizzaro, Christopher; Daheron, Laurence; Messmer, Brady; Vunjak-Novakovic, Gordana; Kaplan, David L.

2009-01-01

48

Chapter 8. Noninvasive imaging of blood vessels.  

PubMed

Angiogenesis is a key component in several major clinical conditions including cancer, diabetic retinopathy, rheumatoid arthritis, endometriosis and psoriasis. All these diseases could be managed much more effectively if their angiogenic capacities were somehow curtailed. Hence there is great interest in developing a fuller understanding of angiogenesis and designing agents to suppress, guide, and normalize this process. Although much has been learned from in vitro methods, the perspective is limited because angiogenesis depends on active blood flow and a variety of circulating precursor cells provided by the intact host. Therefore, noninvasive in vivo methods that provide information over days and weeks are needed. Accordingly, the rodent dorsal skinfold tissue window chamber facilitates the imaging of new vessels around implanted cells, around an injury, or around a simple device impregnated with growth factors. Tissue oxygen levels can be measured during the course of angiogenesis using a window chamber that is also fitted with a miniature multiple electrode sensor. The present review describes window chamber methods and hardware, the measurement of oxygen, and the introduction into the chamber of tumors, growth factors, and organs to induce angiogenesis. The application of multiphoton microscopy to intravital imaging is discussed, along with a description of how to modify a standard brightfield or fluorescence microscope for multiphoton imaging of window chamber microvessels. PMID:19007665

Makale, Milan

2008-01-01

49

Contact-Inhibited Chemotaxis in De Novo and Sprouting Blood-Vessel Growth  

PubMed Central

Blood vessels form either when dispersed endothelial cells (the cells lining the inner walls of fully formed blood vessels) organize into a vessel network (vasculogenesis), or by sprouting or splitting of existing blood vessels (angiogenesis). Although they are closely related biologically, no current model explains both phenomena with a single biophysical mechanism. Most computational models describe sprouting at the level of the blood vessel, ignoring how cell behavior drives branch splitting during sprouting. We present a cell-based, Glazier–Graner–Hogeweg model (also called Cellular Potts Model) simulation of the initial patterning before the vascular cords form lumens, based on plausible behaviors of endothelial cells. The endothelial cells secrete a chemoattractant, which attracts other endothelial cells. As in the classic Keller–Segel model, chemotaxis by itself causes cells to aggregate into isolated clusters. However, including experimentally observed VE-cadherin–mediated contact inhibition of chemotaxis in the simulation causes randomly distributed cells to organize into networks and cell aggregates to sprout, reproducing aspects of both de novo and sprouting blood-vessel growth. We discuss two branching instabilities responsible for our results. Cells at the surfaces of cell clusters attempting to migrate to the centers of the clusters produce a buckling instability. In a model variant that eliminates the surface–normal force, a dissipative mechanism drives sprouting, with the secreted chemical acting both as a chemoattractant and as an inhibitor of pseudopod extension. Both mechanisms would also apply if force transmission through the extracellular matrix rather than chemical signaling mediated cell–cell interactions. The branching instabilities responsible for our results, which result from contact inhibition of chemotaxis, are both generic developmental mechanisms and interesting examples of unusual patterning instabilities.

Merks, Roeland M. H.; Perryn, Erica D.; Shirinifard, Abbas; Glazier, James A.

2008-01-01

50

Micro-PIV measurements of blood flow in extraembryonic blood vessels of chicken embryos  

Microsoft Academic Search

The hemodynamic characteristics of blood flow are important in the diagnosis of circulatory diseases, since such diseases are related to wall shear stress of cardiovascular vessels. In chicken embryos at early stages of development, it is possible to directly visualize blood flow inside blood vessels. We therefore employed a micro-PIV technique to assess blood flow in extraembryonic venous and arterial

Jung Yeop Lee; Ho Seong Ji; Sang Joon Lee

2007-01-01

51

Non-Newtonian flow of blood in an arteriosclerotic blood vessel with rigid permeable walls  

Microsoft Academic Search

The steady, laminar and fully developed flow of blood in an arteriosclerotic blood vessel with rigid permeable walls is investigated, taking into account the slip condition at the vessel walls. The constitutive equation of blood is represented by a Casson fluid model. The model is used to study the influence of the yield stress on blood flow through arteriosclerotic arteries.

Bigyani Das; R. L. Batra

1995-01-01

52

Selective photocoagulation of cutaneous blood vessels: evaluation of vessel damage by color Doppler optical coherence tomography  

NASA Astrophysics Data System (ADS)

This study investigates the threshold radiant exposures required to irreversibly damage cutaneous blood vessels using a pulsed dye laser (PDL) operating at 585 nm. Evaluation of blood vessel damage and blood flow stoppage was achieved using Doppler imaging in a color Doppler optical coherence tomographic (CDOCT) system. Hamster dorsal skin flap window vessels were irradiated with radiant exposures ranging from 2.5 - 8 J/cm2. A 5 mm spot size and 360 microsecond pulse duration were used. Irradiation sites were imaged with CDOCT prior to, immediately after, and a minimum of 24 hours after delivery of laser energy. Magnitude and color Doppler images provided information such as approximate vessel size, depth, and changes in blood flow velocity. Vessel stenosis, temporary occlusion, permanent occlusion, hemorrhaging, and changes in flow velocity were frequent results of laser irradiation visualized with CDOCT and video imaging. Probit analysis was used to estimate the 50% probability that a blood vessel of given size and type will be destroyed by a given radiant exposure. In most instances, arterioles required higher radiant exposures to be irreversibly damaged than venules of the same size. However, arteriole/venule pairs required approximately the same radiant exposures for visible damage to occur. Vessels of larger diameter required higher radiant exposures to coagulate than vessels of smaller diameter.

Vargas, Gracie; Ducros, Mathieu G.; Dozier, Susan; Barton, Jennifer K.; Welch, Ashley J.

2000-05-01

53

Evaluation of blood vessel detection methods  

NASA Astrophysics Data System (ADS)

We address the problem of evaluating the performance of algorithms for detecting curvilinear structures in medical images. As an exemplar we consider the detection of vessel trees which contain structures of variable width and contrast. Results for the conventional approach to evaluation, in which the detector output is compared directly with a groundtruth mask, tend to be dominated by the detection of large vessels and fail to capture adequately whether or not finer, lower contrast vessels have been detected successfully. We propose and investigate three alternative evaluation strategies. We demonstrate the use of the standard and new evaluation strategies to assess the performance of a novel method for detecting vessels in retinograms, using the publicly available DRIVE database.

Sadeghzadeh, R.; Berks, M.; Astley, S. M.; Taylor, C. J.

2011-03-01

54

Blood vessel segmentation using multi-scale quadrature filtering  

Microsoft Academic Search

The segmentation of blood vessels is a common problem in medical imaging and various applications are found in diagnostics, surgical planning, training and more. Among many different techniques, the use of multiple scales and line detectors is a popular approach. However, the typical line filters used are sensitive to intensity variations and do not target the detection of vessel walls

Gunnar Läthén; Jimmy Jonasson; Magnus Borga

2010-01-01

55

Vascular-specific growth factors and blood vessel formation  

Microsoft Academic Search

A recent explosion in newly discovered vascular growth factors has coincided with exploitation of powerful new genetic approaches for studying vascular development. An emerging rule is that all of these factors must be used in perfect harmony to form functional vessels. These new findings also demand re-evaluation of therapeutic efforts aimed at regulating blood vessel growth in ischaemia, cancer and

George D. Yancopoulos; Samuel Davis; Nicholas W. Gale; John S. Rudge; Stanley J. Wiegand; Jocelyn Holash

2000-01-01

56

Crosstalk Between Perivascular Adipose Tissue and Blood Vessels  

PubMed Central

Crosstalk between cells in the blood vessel wall is vital to normal vascular function and is perturbed in diseases such as atherosclerosis and hypertension. Perivascular adipocytes reside at the adventitial border of blood vessels but until recently were virtually ignored in studies of vascular function. However, perivascular adipocytes have been demonstrated to be powerful endocrine cells capable of responding to metabolic cues and transducing signals to adjacent blood vessels. Accordingly, crosstalk between perivascular adipose tissue (PVAT) and blood vessels is now being intensely examined. Emerging evidence suggests that PVAT regulates vascular function through numerous mechanisms, but evidence to date suggests modulation of three key aspects that are the focus of this review: inflammation, vasoreactivity, and smooth muscle cell proliferation.

Rajsheker, Srinivas; Manka, David; Blomkalns, Andra L.; Chatterjee, Tapan K.; Stoll, Lynn L.; Weintraub, Neal L.

2009-01-01

57

Organ blood flow and vessels of microcirculatory bed in fish  

Microsoft Academic Search

Information on density of fish capillary network and its permeability, peculiarities of geometry, morphology, and ultrastructure\\u000a of vessels of microcirculation bed—arterioles, venules, capillaries—is presented. A great attention is paid to vasomotor reactions\\u000a and their participation in redistribution of blood. Nervous and humoral mechanisms of control of tone of the vessel smooth\\u000a muscle wall and voluminous blood flow are considered. Effects

A. A. Soldatov

2006-01-01

58

Allogeneic human tissue-engineered blood vessel  

PubMed Central

Background Arterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease; however, there is no available synthetic small-diameter vascular graft. Methods Tissue-engineered vessels were grown from human smooth muscle cells that were seeded on a biodegradable scaffold using a biomimetic perfusion system. The human tissue-engineered vessels (hTEV) were decellularized by a two-step process using a combination of detergents and hypertonic solutions. The mechanical characteristics were assessed by suture retention strength and burst pressure. The decellularized hTEV were implanted as aortic interpositional grafts in nude rats to evaluate in vivo performance as an arterial graft over a 6-week period. Results The human tissue-engineered structure formed a vessel composed of smooth muscle cells and the extracellular matrix proteins, including collagen. After decellularization, the collagen matrix remained intact while the cellular components were removed. The mechanical strength of the hTEV after decellularization was similar to human vein in vitro, with a burst pressure of 1,567 ± 384 mm Hg (n = 3) versus 1,680 ± 307 mm Hg for human saphenous vein. The hTEVs had a high patency rate (four of five grafts) without evidence of rupture or aneurysm over a 6-week period as an aortic interpositional graft in a nude rat model. Histologic analysis showed a thin neointima with a confluent endothelium and a subendothelial layer of smooth muscle cells on the explanted tissue-engineered vessels. Transmission electron microscopy on the explanted tissue demonstrated elastin formation in the neointima and intact residual collagen fibers from the tissue-engineered vessel. Conclusions The hTEV had a high patency rate and remained mechanically stable as an aortic interpositional graft in a nude rat. The vessel supported the growth of a neointima with endothelial cells and smooth muscle cells. The host remodeling suggested the engineered matrix had a positive effect to create a regenerated vascular graft.

Quint, Clay; Arief, Melissa; Muto, Akihito; Dardik, Alan; Niklason, Laura E.

2012-01-01

59

Retinal blood vessel detection using wavelet-matched filter  

NASA Astrophysics Data System (ADS)

A novel method for retinal blood vessel detection by using a wavelet-matched filter is proposed to improve the detection performance. Vessel references are generated by using dual Gaussian functions with different widths, separations, and orientations, while a Mexican hat wavelet is used for feature enhancements. The results show that the proposed method has advantages over the conventional matched filter in that the vessels can be easily distinguished from the fluctuating background without the need of a thresholding process, and vessel images can be precisely reconstructed.

Widjaja, Joewono; Suripon, Ubon

2013-03-01

60

Application of fuzzy connectedness in 3D blood vessel extraction.  

PubMed

Three-dimensional (3D) segmentation of blood vessels plays a very important role in solving some practical problems such as diagnosis of vessels diseases. Because of the effective segmentation for 2D images, the fuzzy connectedness segmentation method is introduced to extract vascular structures from 3D blood vessel volume dataset. In the experiments, three segmentation methods including thresholding method, region growing method and fuzzy connectedness method are all used to extract the vascular structures, and their results are compared. The results indicate that fuzzy connectedness method is better than thresholding method in connectivity of segmentation results, and better than region growing method in precision of segmentation results. PMID:21224204

Lv, Xinrong; Zou, Hua

2010-01-01

61

Mouse blood vessel imaging by in-line x-ray phase-contrast imaging.  

PubMed

It is virtually impossible to observe blood vessels by conventional x-ray imaging techniques without using contrast agents. In addition, such x-ray systems are typically incapable of detecting vessels with diameters less than 200 microm. Here we show that vessels as small as 30 microm could be detected using in-line phase-contrast x-ray imaging without the use of contrast agents. Image quality was greatly improved by replacing resident blood with physiological saline. Furthermore, an entire branch of the portal vein from the main axial portal vein to the eighth generation of branching could be captured in a single phase-contrast image. Prior to our work, detection of 30 microm diameter blood vessels could only be achieved using x-ray interferometry, which requires sophisticated x-ray optics. Our results thus demonstrate that in-line phase-contrast x-ray imaging, using physiological saline as a contrast agent, provides an alternative to the interferometric method that can be much more easily implemented and also offers the advantage of a larger field of view. A possible application of this methodology is in animal tumor models, where it can be used to observe tumor angiogenesis and the treatment effects of antineoplastic agents. PMID:18824782

Zhang, Xi; Liu, Xiao-Song; Yang, Xin-Rong; Chen, Shao-Liang; Zhu, Pei-Ping; Yuan, Qing-Xi

2008-09-26

62

Mouse blood vessel imaging by in-line x-ray phase-contrast imaging  

NASA Astrophysics Data System (ADS)

It is virtually impossible to observe blood vessels by conventional x-ray imaging techniques without using contrast agents. In addition, such x-ray systems are typically incapable of detecting vessels with diameters less than 200 µm. Here we show that vessels as small as 30 µm could be detected using in-line phase-contrast x-ray imaging without the use of contrast agents. Image quality was greatly improved by replacing resident blood with physiological saline. Furthermore, an entire branch of the portal vein from the main axial portal vein to the eighth generation of branching could be captured in a single phase-contrast image. Prior to our work, detection of 30 µm diameter blood vessels could only be achieved using x-ray interferometry, which requires sophisticated x-ray optics. Our results thus demonstrate that in-line phase-contrast x-ray imaging, using physiological saline as a contrast agent, provides an alternative to the interferometric method that can be much more easily implemented and also offers the advantage of a larger field of view. A possible application of this methodology is in animal tumor models, where it can be used to observe tumor angiogenesis and the treatment effects of antineoplastic agents.

Zhang, Xi; Liu, Xiao-Song; Yang, Xin-Rong; Chen, Shao-Liang; Zhu, Pei-Ping; Yuan, Qing-Xi

2008-10-01

63

Three-dimensional reconstruction of blood vessels in the rabbit eye by X-ray phase contrast imaging  

PubMed Central

Background A clear understanding of the blood vessels in the eye is helpful in the diagnosis and treatment of ophthalmic diseases, such as glaucoma. Conventional techniques such as micro-CT imaging and histology are not sufficiently accurate to identify the vessels in the eye, because their diameter is just a few microns. The newly developed medical imaging technology, X-ray phase-contrast imaging (XPCI), is able to distinguish the structure of the vessels in the eye. In this study, XPCI was used to identify the internal structure of the blood vessels in the eye. Methods After injection with barium sulfate via the ear border artery, an anesthetized rabbit was killed and its eye was fixed in vitro in 10% formalin solution. We acquired images using XPCI at the Shanghai Synchrotron Radiation Facility. The datasets were converted into slices by filtered back-projection (FBP). An angiographic score was obtained as a parameter to quantify the density of the blood vessels. A three-dimensional (3D) model of the blood vessels was then established using Amira 5.2 software. Results With XPCI, blood vessels in the rabbit eye as small as 18 ?m in diameter and a sixth of the long posterior ciliary artery could be clearly distinguished. In the 3D model, we obtained the level 4 branch structure of vessels in the fundus. The diameters of the arteria centralis retinae and its branches are about 200 ?m, 110 ?m, 95 ?m, 80 ?m and 40 ?m. The diameters of the circulus arteriosus iridis major and its branches are about 210 ?m, 70 ?m and 30 ?m. Analysis of vessel density using the angiographic score showed that the blood vessels had maximum density in the fundus and minimum density in the area anterior to the equator (scores 0.27?±?0.029 and 0.16?±?0.032, respectively). We performed quantitative angiographic analysis of the blood vessels to further investigate the density of the vessels. Conclusions XPCI provided a feasible means to determine the structure of the blood vessels in the eye. We were able to determine the diameters and morphological characteristics of the vessels from both 2D images and the 3D model. By analyzing the images, we obtained measurements of the density distribution of the microvasculature, and this approach may provide valuable reference information prior to glaucoma filtration surgery.

2013-01-01

64

Probabilistic Modeling of Blood Vessels for Segmenting MRA Images  

Microsoft Academic Search

A new physically justified adaptive probabilistic model of blood vessels on magnetic resonance angiography (MRA) images is proposed. The model accounts for both laminar (for normal subjects) and turbulent blood flow (in abnormal cases like anemia or stenosis) and results in a fast algorithm for extracting a 3D cerebrovascular system from the MRA data. Experiments with real data sets confirm

Ayman El-baz; Aly A. Farag; Georgy L. Gimel'farb; Mohamed Abou El-ghar; Tarek Eldiasty

2006-01-01

65

Arterial-Venous Segregation by Selective Cell Sprouting: An Alternative Mode of Blood Vessel Formation  

Microsoft Academic Search

Blood vessels form de novo (vasculogenesis) or upon sprouting of capillaries from preexisting vessels (angiogenesis). With high-resolution imaging of zebrafish vascular development, we uncovered a third mode of blood vessel formation whereby the first embryonic artery and vein, two unconnected blood vessels, arise from a common precursor vessel. The first embryonic vein formed by selective sprouting of progenitor cells from

Shane P. Herbert; Jan Huisken; Tyson N. Kim; Morri E. Feldman; Benjamin T. Houseman; Rong A. Wang; Kevan M. Shokat; Didier Y. R. Stainier

2009-01-01

66

Blood Vessel Adaptation with Fluctuations in Capillary Flow Distribution  

PubMed Central

Throughout the life of animals and human beings, blood vessel systems are continuously adapting their structures – the diameter of vessel lumina, the thickness of vessel walls, and the number of micro-vessels – to meet the changing metabolic demand of the tissue. The competition between an ever decreasing tendency of luminal diameters and an increasing stimulus from the wall shear stress plays a key role in the adaptation of luminal diameters. However, it has been shown in previous studies that the adaptation dynamics based only on these two effects is unstable. In this work, we propose a minimal adaptation model of vessel luminal diameters, in which we take into account the effects of metabolic flow regulation in addition to wall shear stresses and the decreasing tendency of luminal diameters. In particular, we study the role, in the adaptation process, of fluctuations in capillary flow distribution which is an important means of metabolic flow regulation. The fluctuation in the flow of a capillary group is idealized as a switch between two states, i.e., an open-state and a close-state. Using this model, we show that the adaptation of blood vessel system driven by wall shear stress can be efficiently stabilized when the open time ratio responds sensitively to capillary flows. As micro-vessel rarefaction is observed in our simulations with a uniformly decreased open time ratio of capillary flows, our results point to a possible origin of micro-vessel rarefaction, which is believed to induce hypertension.

Hu, Dan; Cai, David; Rangan, Aaditya V.

2012-01-01

67

Assessement of angiogenesis reveals blood vessel heterogeneity in lung carcinoma  

PubMed Central

Despite advances in treatment, the prognosis for lung cancer patients remains poor. Angiogenesis appears to be a promising target for lung cancer therapy; however, the clinical significance of vascular changes are not completely understood. The aim of this study was to evaluate the types and morphology of blood vessels in various lung carcinomas. Using double immunostaining, we investigated 39 biopsies from patients admitted with various histological types of lung carcinoma. Tumor blood vessels were quantified separately for CD34/smooth muscle actin and described as either immature, intermediate or mature. Double immunostaining evaluation of the type of blood vessels in lung carcinomas revealed a marked heterogeneity. The immature and intermediate type of vessels were more common in adenocarcinomas (ADCs) and squamous cell carcinomas (SCCs) of the lung. Small cell lung carcinomas revealed a significant correlation between pathological and immature types of blood vessels. Therefore, quantifying the types of tumor vessels in lung carcinomas may be an important element to improve the results of anti-vascular therapy.

BIRAU, AMALIA; CEAUSU, RALUCA AMALIA; CIMPEAN, ANCA MARIA; GAJE, PUSA; RAICA, MARIUS; OLARIU, TEODORA

2012-01-01

68

Analysis of Blood Flow in a Partially Blocked Bifurcated Blood Vessel  

NASA Astrophysics Data System (ADS)

Coronary artery disease is a major cause of death in the United States. It is the narrowing of the lumens of the coronary blood vessel by a gradual build-up of fatty material, atheroma, which leads to the heart muscle not receiving enough blood. This my ocardial ischemia can cause angina, a heart attack, heart failure as well as sudden cardiac death [9]. In this project a solid model of bifurcated blood vessel with an asymmetric stenosis is developed using GAMBIT and imported into FLUENT for analysis. In FLUENT, pressure and velocity distributions in the blood vessel are studied under different conditions, where the size and position of the blockage in the blood vessel are varied. The location and size of the blockage in the blood vessel are correlated with the pressures and velocities distributions. Results show that such correlation may be used to predict the size and location of the blockage.

Abdul-Razzak, Hayder; Elkassabgi, Yousri; Punati, Pavan K.; Nasser, Naseer

2009-09-01

69

What Determines Blood Vessel Structure? Genetic Prespecification vs. Hemodynamics  

NSDL National Science Digital Library

Vascular network remodeling, angiogenesis, and arteriogenesis play an important role in the pathophysiology of ischemic cardiovascular diseases and cancer. Based on recent studies of vascular network development in the embryo, several novel aspects to angiogenesis have been identified as crucial to generate a functional vascular network. These aspects include specification of arterial and venous identity in vessels and network patterning. In early embryogenesis, vessel identity and positioning are genetically hardwired and involve neural guidance genes expressed in the vascular system. We demonstrated that, during later stages of embryogenesis, blood flow plays a crucial role in regulating vessel identity and network remodeling. The flow-evoked remodeling process is dynamic and involves a high degree of vessel plasticity. The open question in the field is how genetically predetermined processes in vessel identity and patterning balance with the contribution of blood flow in shaping a functional vascular architecture. Although blood flow is essential, it remains unclear to what extent flow is able to act on the developing cardiovascular system. There is significant evidence that mechanical forces created by flowing blood are biologically active within the embryo and that the level of mechanical forces and the type of flow patterns present in the embryo are able to affect gene expression. Here, we highlight the pivotal role for blood flow and physical forces in shaping the cardiovascular system.

Elizabeth A. V. Jones (College de France); Ferdinand Noble (College de Frence); Anne Eichmann (College de France)

2006-10-01

70

Expression of serotonin receptor mRNAs in blood vessels  

Microsoft Academic Search

Using RT-PCR we distinguished mRNAs for all known G-protein coupled serotonin receptors expressed in various rat and porcine blood vessels. Nearly all vessels expressed 5HT1d?, 5-HT2A, 5-HT2B, 5-HT4, and 5-Ht7 receptor mRNA to different extents. New splice variants of the porcine 5-HT4 receptor were observed. Similar PCR assays were performed with endothelial and smooth muscle cells from human pulmonary artery,

Christoph Ullmer; Karin Schmuck; Hans O. Kalkman; Hermann Lübbert

1995-01-01

71

Vessel and blood specification override cardiac potential in anterior mesoderm  

PubMed Central

SUMMARY Organ progenitors arise within organ fields, embryonic territories that are larger than the regions required for organ formation. Little is known about the regulatory pathways that define organ field boundaries and thereby limit organ size. Here, we identify a mechanism for restricting heart size through confinement of the developmental potential of the heart field. Via fate mapping in zebrafish, we locate cardiac progenitors within hand2-expressing mesoderm and demonstrate that hand2 potentiates cardiac differentiation within this region. Beyond the rostral boundary of hand2 expression, we find progenitors of vessel and blood lineages. In embryos deficient in vessel and blood specification, rostral mesoderm undergoes a fate transformation and generates ectopic cardiomyocytes. Therefore, induction of vessel and blood specification represses cardiac specification and delimits the capacity of the heart field. This regulatory relationship between cardiovascular pathways suggests new strategies for directing progenitor cell differentiation to facilitate cardiac regeneration.

Schoenebeck, Jeffrey J.; Keegan, Brian R.; Yelon, Deborah

2009-01-01

72

Acrolein generation stimulates hypercontraction in isolated human blood vessels  

PubMed Central

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertension—all conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H2O2 exposure (1 ?M–1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 ?M), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca2+ to hypercontraction. Acrolein or allylamine but not H2O2, benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca2+-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in Sprague–Dawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension.

Conklin, D.J.; Bhatnagar, A.; Cowley, H.R.; Johnson, G.H.; Wiechmann, R.J.; Sayre, L.M.; Trent, M.B.; Boor, P.J.

2012-01-01

73

Acrolein generation stimulates hypercontraction in isolated human blood vessels  

SciTech Connect

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertension-all conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H{sub 2}O{sub 2} exposure (1 {mu}M-1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 {mu}M), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca{sup 2+} to hypercontraction. Acrolein or allylamine but not H{sub 2}O{sub 2}, benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca{sup 2+}-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in Sprague-Dawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension.

Conklin, D.J. [Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, KY 40202 (United States) and Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54701 (United States)]. E-mail: dj.conklin@louisville.edu; Bhatnagar, A. [Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, KY 40202 (United States); Cowley, H.R. [Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54701 (United States); Johnson, G.H. [Department of Cardiothoracic Surgery, Luther Hospital/Midelfort Clinic, Eau Claire, WI 54702 (United States); Wiechmann, R.J. [Department of Cardiothoracic Surgery, Luther Hospital/Midelfort Clinic, Eau Claire, WI 54702 (United States); Sayre, L.M. [Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106 (United States); Trent, M.B. [Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555-0609 (United States); Boor, P.J. [Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555-0609 (United States)

2006-12-15

74

Molded Parallel Endografts for Branch Vessel Preservation during Endovascular Aneurysm Repair in Challenging Anatomy  

PubMed Central

Parallel endografts (also known as snorkels or chimneys) are a proposed strategy for increasing the applicability of endovascular repair to aneurysms involving branch vessels. One major disadvantage of this strategy is the imperfect nature of seal inherent to having multiple side-by-side endografts. In this article, the use of odd-shaped parallel endografts to facilitate apposition and improve seal is proposed and a technique to mold a round stent graft into an “eye” shape using balloons is described.

Minion, David

2012-01-01

75

The Fine Structure of Some Blood Vessels of the Earthworm, Eisenia foetida  

PubMed Central

The fine structure of the main dorsal and ventral circulatory trunks and of the subneural vessels and capillaries of the ventral nerve cord of the earthworm, Eisenia foetida, has been studied with the electron microscope. All of these vessels are lined internally by a continuous extracellular basement membrane varying in thickness (0.03 to 1 µ) with the vessel involved. The dorsal, ventral, and subneural vessels display inside this membrane scattered flattened macrophagic or leucocytic cells called amebocytes. These lie against the inner lining of the basement membrane, covering only a small fraction of its surface. They have long, attenuated branching cell processes. All of these vessels are lined with a continuous layer of unfenestrated endothelial cells displaying myofilaments and hence qualifying for the designation of "myoendothelial cells." The degree of muscular specialization varies over a spectrum, however, ranging from a delicate endowment of thin myofilaments in the capillary myoendothelial cells to highly specialized myoendothelial cells in the main pulsating dorsal blood trunk, which serves as the worm's "heart" or propulsive "aorta." The myoendothelial cells most specialized for contraction display well organized sarcoplasmic reticulum and myofibrils with thick and thin myofilaments resembling those of the earthworm body wall musculature. In the ventral circulatory trunk, circular and longitudinal myofilaments are found in each myoendothelial cell. In the dorsal trunk, the lining myoendothelial cells contain longitudinal myofilaments. Outside these cells are circular muscle cells. The lateral parts of the dorsal vessels have an additional outer longitudinal muscle layer. The blood plasma inside all of the vessels shows scattered particles representing the circulating earthworm blood pigment, erythrocruorin.

Hama, Kiyoshi

1960-01-01

76

Vasculogenensis, angiogenesis and special features of tumor blood vessels.  

PubMed

The circulatory system comprises a tubular network of blood vessels including arterioles, capillaries, venules, and lymphatic vessels. This circulatory system is essential for the embryonic development and maintenance of all tissues, which requires the transportation of oxygen, carbon dioxide, and nutrition. The system regulates the movement of fluid into and out of organs with high level of efficiency. "Tumor angiogenesis" describes the rapid growth of certain components of the circulatory system in an abnormal fashion that is both heterogeneous and dysregulated. The aberrant flow between abnormal tumor vessels and normal vessels poses a high risk for seeding of potentially metastatic cancer cells. Moreover, it has also been reported that premetastatic distant organ vessels already undergo specific changes due to the presence of a remote primary tumor. Therapeutic strategies aimed at targeting tumor vessels have the potential to suppress tumor growth, and also influence the effects of tumor-derived cytokines and circulating tumor cells. Furthermore, focusing on vessels in a premetastatic organ that have responded to a primary tumor may be one possibility for reducing metastatic risk. PMID:21196239

Hiratsuka, Sachie

2011-01-01

77

The Influence of Larger Subcutaneous Blood Vessels on Pulse Oximetry  

Microsoft Academic Search

Objective. Recent studies have renewed interest in reflectance pulse oximetry, specifically for monitoring the patient's forehead. Blood circulation on the forehead immediately above the eyebrow is fed by arteries that branch from the internal carotid artery and lack the vasoconstrictor response present in more peripheral regions. Some investigators question, however, the reliability of monitoring SpO2 on the forehead due to

Paul D. Mannheimer; Michael P. O'Neil; Ewald Konecny

2004-01-01

78

Adrenergic and peptidergic innervation of cochlear blood vessels  

Microsoft Academic Search

Guinea pig cochlear blood vessels were investigated with regard to their supply of adrenergic and peptidergic nerve fibers. Using the glyoxylic acid histofluorescence technique, numerous adrenergic fibers were seen around the labyrinthine artery, whereas the spiral modiolar artery contained only few such fibers. Immunocytochemistry revealed nerve fibers containing immunoreactive avian pancreatic polypeptide, vasoactive intestinal peptide, substance P, or gastrin-releasing peptide

R. Uddman; O. Ninoyu; F. Sundler

1982-01-01

79

Fractal structures in stenoses and aneurysms in blood vessels  

PubMed Central

Recent advances in the field of chaotic advection provide the impetus to revisit the dynamics of particles transported by blood flow in the presence of vessel wall irregularities. The irregularity, being either a narrowing or expansion of the vessel, mimicking stenoses or aneurysms, generates abnormal flow patterns that lead to a peculiar filamentary distribution of advected particles, which, in the blood, would include platelets. Using a simple model, we show how the filamentary distribution depends on the size of the vessel wall irregularity, and how it varies under resting or exercise conditions. The particles transported by blood flow that spend a long time around a disturbance either stick to the vessel wall or reside on fractal filaments. We show that the faster flow associated with exercise creates widespread filaments where particles can get trapped for a longer time, thus allowing for the possible activation of such particles. We argue, based on previous results in the field of active processes in flows, that the non-trivial long-time distribution of transported particles has the potential to have major effects on biochemical processes occurring in blood flow, including the activation and deposition of platelets. One aspect of the generality of our approach is that it also applies to other relevant biological processes, an example being the coexistence of plankton species investigated previously.

Schelin, Adriane B.; Karolyi, Gyorgy; de Moura, Alessandro P. S.; Booth, Nuala A.; Grebogi, Celso

2010-01-01

80

Blood vessels and nerves: common signals, pathways and diseases  

Microsoft Academic Search

Both blood vessels and nerves are vital channels to and from tissues. Recent genetic insights show that they have much more in common than was originally anticipated. They use similar signals and principles to differentiate, grow and navigate towards their targets. Moreover, the vascular and nervous systems cross-talk and, when dysregulated, this contributes to medically important diseases. The realization that

Peter Carmeliet

2003-01-01

81

Potential Role of Microglia in Retinal Blood Vessel Formation  

Microsoft Academic Search

PURPOSE. The role of microglia, present in the retina early in development before vascularization, remains ill defined. The authors investigated whether microglia are implicated in reti- nal blood vessel formation. METHODS. The microglia and vasculature of developing human fetal and rodent retinas were examined by labeling the endo- thelial cells with lectin and the microglia with CD18 antibody or green

Daniella Checchin; Florian Sennlaub; Etienne Levavasseur; Martin Leduc; Sylvain Chemtob

82

Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation  

Microsoft Academic Search

Experiments of in vitro formation of blood vessels show that cells randomly spread on a gel matrix autonomously organize to form a connected vascular network. We propose a simple model which reproduces many features of the biological system. We show that both the model and the real system exhibit a fractal behavior at small scales, due to the process of

A. Gamba; D. Ambrosi; A. Coniglio; A. de Candia; S. di Talia; E. Giraudo; G. Serini; L. Preziosi; F. Bussolino

2003-01-01

83

Local stenosis hemodynamics evaluated by a tapered blood vessel model  

Microsoft Academic Search

A computer model of a tapered blood vessel was developed to investigate the effects of arterial stenosis on pulse transmission properties. Significant increases in phase velocity (Cph), characteristic impedance (ZO), and local reflection coefficients (?L) were found with increasing severity of the stenosis

John P. Matonick; Prabhakar Viswanathan; Jai Agarwal; J. K.-J. Li

1999-01-01

84

Numerical Investigation of Pulsatile Blood Flow in a Bifurcation Model with a Non-Planar Branch: The Effect of Different Bifurcation Angles and Non-Planar Branch  

PubMed Central

Introduction Atherosclerosis is a focal disease that susceptibly forms near bifurcations, anastomotic joints, side branches, and curved vessels along the arterial tree. In this study, pulsatile blood flow in a bifurcation model with a non-planar branch is investigated. Methods Wall shear stress (WSS) distributions along generating lines on vessels for different bifurcation angles are calculated during the pulse cycle. Results The WSS at the outer side of the bifurcation plane vanishes especially for higher bifurcation angles but by increasing the bifurcation angle low WSS region squeezes. At the systolic phase there is a high possibility of formation of a separation region at the outer side of bifurcation plane for all the cases. WSS peaks exist on the inner side of bifurcation plane near the entry section of daughter vessels and these peaks drop as bifurcation angle is increased. Conclusion It was found that non-planarity of the daughter vessel lowers the minimum WSS at the outer side of the bifurcation and increases the maximum WSS at the inner side. So it seems that the formation of atherosclerotic plaques at bifurcation region in direction of non-planar daughter vessel is more risky.

Arjmandi Tash, Omid; Razavi, Seyed Esmail

2012-01-01

85

Twisted Blood Vessels: Symptoms, Etiology and Biomechanical Mechanisms  

PubMed Central

Tortuous arteries and veins are commonly observed in humans and animals. While mild tortuosity is asymptomatic, severe tortuosity can lead to ischemic attack in distal organs. Clinical observations have linked tortuous arteries and veins with aging, atherosclerosis, hypertension, genetic defects and diabetes mellitus. However, the mechanisms of their formation and development are poorly understood. This review summarizes the current clinical and biomechanical studies on the initiation, development and treatment of tortuous blood vessels. We submit a new hypothesis that mechanical instability and remodeling could be mechanisms for the initiation and development of these tortuous vessels.

Han, Hai-Chao

2012-01-01

86

Deformations and end effects in isolated blood vessel testing.  

PubMed

Blood vessels are commonly studied in isolation to define their mechanical and biological properties under controlled conditions. While sections of the wall are sometimes tested, vessels are most often attached to needles and examined in their natural cylindrical configuration where combinations of internal pressure and axial force can be applied to mimic in vivo conditions. Attachments to needles, however, constrain natural vessel response, resulting in a complex state of deformation that is not easily determined. As a result, measurements are usually limited to the midsection of a specimen where end effects do not extend and the deformation is homogeneous. To our knowledge, however, the boundaries of this uninfluenced midsection region have not been explored. The objective of this study was to define the extent of these end effects as a function of vessel geometry and material properties, loading conditions, and needle diameter. A computational fiber framework was used to model the response of a nonlinear anisotropic cylindrical tube, constrained radially at its ends, under conditions of axial extension and internal pressure. Individual fiber constitutive response was defined using a Fung-type strain energy function. While quantitative results depend on specific parameter values, simulations demonstrate that axial stretch is always highest near the constraint and reduces to a minimum in the uninfluenced midsection region. Circumferential stretch displays the opposite behavior. As a general rule, the length of the region disturbed by a needle constraint increases with the difference between the diameter of the needle and the equilibrium diameter of the blood vessel for the imposed loading conditions. The reported findings increase the understanding of specimen deformation in isolated vessel experiments, specifically defining considerations important to identifying a midsection region appropriate for measurement. PMID:21186895

Monson, Kenneth L; Mathur, Vishwas; Powell, David A

2011-01-01

87

Lattice Boltzmann Simulation of Blood Flow in Blood Vessels with the Rolling Massage  

NASA Astrophysics Data System (ADS)

The rolling massage manipulation is a classic Chinese massage, which is expected to improve the circulation by pushing, pulling and kneading of the muscle. A model for the rolling massage manipulation is proposed and the lattice Boltzmann method is applied to study the blood flow in the blood vessels. The simulation results show that the blood flux is considerably modified by the rolling massage and the explicit value depends on the rolling frequency, the rolling depth, and the diameter of the vessel. The smaller the diameter of the blood vessel, the larger the enhancement of the blood flux by the rolling massage. The model, together with the simulation results, is expected to be helpful to understand the mechanism and further development of rolling massage techniques.

Yi, Hou-Hui; Xu, Shi-Xiong; Qian, Yue-Hong; Fang, Hai-Ping

2005-12-01

88

Isolating and defining cells to engineer human blood vessels.  

PubMed

A great deal of attention has been recently focused on understanding the role that bone marrow-derived putative endothelial progenitor cells (EPC) may play in the process of neoangiogenesis. However, recent data indicate that many of the putative EPC populations are comprised of various haematopoietic cell subsets with proangiogenic activity, but these marrow-derived putative EPC fail to display vasculogenic activity. Rather, this property is reserved for a rare population of circulating viable endothelial cells with colony-forming cell (ECFC) ability. Indeed, human ECFC possess clonal proliferative potential, display endothelial and not haematopoietic cell surface antigens, and display in vivo vasculogenic activity when suspended in an extracellular matrix and implanted into immunodeficient mice. Furthermore, human vessels derived became integrated into the murine circulatory system and eventually were remodelled into arterial and venous vessels. Identification of this population now permits determination of optimal type I collagen matrix microenvironment into which the cells should be embedded and delivered to accelerate and even pattern number and size of blood vessels formed, in vivo. Indeed, altering physical properties of ECFC-collagen matrix implants changed numerous parameters of human blood vessel formation, in host mice. These recent discoveries may permit a strategy for patterning vascular beds for eventual tissue and organ regeneration. PMID:21481038

Critser, P J; Voytik-Harbin, S L; Yoder, M C

2011-04-01

89

Regional blood flow analysis and its relationship with arterial branch lengths and lumen volume in the coronary arterial tree  

NASA Astrophysics Data System (ADS)

The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions (30-70% diameter stenosis) where it is difficult to determine whether a particular lesion is the cause of ischaemia. Therefore, a functional measure of stenosis severity is needed. The purpose of this study is to determine whether the expected maximum coronary blood flow in an arterial tree is predictable from its sum of arterial branch lengths or lumen volume. Using a computer model of a porcine coronary artery tree, an analysis of blood flow distribution was conducted through a network of millions of vessels that included the entire coronary artery tree down to the first capillary branch. The flow simulation results show that there is a linear relationship between coronary blood flow and the sum of its arterial branch lengths. This relationship holds over the entire arterial tree. The flow simulation results also indicate that there is a \\frac34 power relation between coronary blood flow (Q) and the sum of its arterial lumen volume (V). Moreover, there is a linear relationship between normalized Q and normalized V raised to a power of \\frac34 over the entire arterial tree. These results indicate that measured arterial branch lengths or lumen volumes can be used to predict the expected maximum blood flow in an arterial tree. This theoretical maximum blood flow, in conjunction with an angiographically measured blood flow, can potentially be used to calculate fractional flow reserve based entirely on angiographic data.

Molloi, Sabee; Wong, Jerry T.

2007-03-01

90

Orientation of endothelial cell division is regulated by VEGF signaling during blood vessel formation  

Microsoft Academic Search

New blood vessel formation requires the coordination of endothelial cell division and the morphogenetic movements of vessel expansion, but it is not known how this integration occurs. Here, we show that endothelial cells regulate division orientation during the earliest stages of blood vessel formation, in response to morphogenetic cues. In embryonic stem (ES) cell-derived vessels that do not expe- rience

Gefei Zeng; Sarah M. Taylor; Janet R. McColm; Nicholas C. Kappas; Joseph B. Kearney; Lucy H. Williams; Mary E. Hartnett; Victoria L. Bautch

2007-01-01

91

Vascular events responsible for thrombotic occlusion of a blood vessel.  

PubMed

In summary, the sequence of endothelial plaque disruption, platelet activation, and thrombogenic factors--that is, the balance between the thrombolytic system and the coagulation system--determine which blood vessel will thrombose and which vessel will remain patent. It seems to me that although the soft plaque with the thin cap and lipid core laden with oxidized LDL-activated macrophages is more prone to rupture than the calcified, hard plaque, it is also the plaque that may regress when the patient is treated aggressively with lipid-lowering or antioxidant therapy. In addition, drugs that lower blood pressure and heart rate may also decrease the tendency of the "vulnerable" plaque to rupture by attenuating fatigue failure. Current and future research should be directed at identifying vulnerable plaques in the individual patient, so that measures can be taken to prevent plaque rupture. PMID:8269651

Conti, C R

1993-11-01

92

Scatter Factor Induces Blood Vessel Formation in vivo  

NASA Astrophysics Data System (ADS)

Scatter factor (also known as hepatocyte growth factor) is a glycoprotein secreted by stromal cells that stimulates cell motility and proliferation. In vitro, scatter factor stimulates vascular endothelial cell migration, proliferation, and organization into capillary-like tubes. Using two different in vivo assays, we showed that physiologic quantities of purified native mouse scatter factor and recombinant human hepatocyte growth factor induce angiogenesis (the formation of new blood vessels). The angiogenic activity was blocked by specific anti-scatter factor antibodies. Scatter factor induced cultured microvascular endothelial cells to accumulate and secrete significantly increased quantities of urokinase, an enzyme associated with development of an invasive endothelial phenotype during angiogenesis. We further showed that immunoreactive scatter factor is present surrounding sites of blood vessel formation in psoriatic skin. These findings suggest that scatter factor may act as a paracrine mediator in pathologic angiogenesis associated with human inflammatory disease.

Grant, Derrick S.; Kleinman, Hynda K.; Goldberg, Itzhak D.; Bhargava, Mahdu M.; Nickoloff, Brian J.; Kinsella, James L.; Polverini, Peter; Rosen, Eliot M.

1993-03-01

93

Stem and progenitor cells in biostructure of blood vessel walls.  

PubMed

Development of vascular and hematopoietic systems during organogenesis occurs at the same time. During vasculogenesis, a small part of cells does not undergo complete differentiation but stays on this level, "anchored" in tissue structures described as stem cell niches. The presence of blood vessels within tissue stem cell niches is typical and led to identification of niches and ensures that they are functioning. The three-layer biostructure of vessel walls for artery and vein, tunica: intima, media and adventitia, for a long time was defined as a mechanical barrier between vessel light and the local tissue environment. Recent findings from vascular biology studies indicate that vessel walls are dynamic biostructures, which are equipped with stem and progenitor cells, described as vascular wall-resident stem cells/progenitor cells (VW-SC/PC). Distinct zones for vessel wall harbor heterogeneous subpopulations of VW-SC/PC, which are described as "subendothelial or vasculogenic zones". Recent evidence from in vitro and in vivo studies show that prenatal activity of stem and progenitor cells is not only limited to organogenesis but also exists in postnatal life, where it is responsible for vessel wall homeostasis, remodeling and regeneration. It is believed that VW-SC/PC could be engaged in progression of vascular disorders and development of neointima. We would like to summarize current knowledge about mesenchymal and progenitor stem cell phenotype with special attention to distribution and biological properties of VW-SC/PC in biostructures of intima, media and adventitia niches. It is postulated that in the near future, niches for VW-SC/PC could be a good source of stem and progenitor cells, especially in the context of vessel tissue bioengineering as a new alternative to traditional revascularization therapies. PMID:24088542

Korta, Krzysztof; Kupczyk, Piotr; Skóra, Jan; Pupka, Artur; Zejler, Pawe?; Ho?ysz, Marcin; Gajda, Mariusz; Nowakowska, Beata; Bar?, Piotr; Dorobisz, Andrzej T; Dawiskiba, Tomasz; Szyber, Piotr; Bar, Julia

2013-09-18

94

The activity of diagnostic enzymes and the concentration of lipids in the blood vessels of cattle  

Microsoft Academic Search

Blood vessel walls are shown to contain creatine phosphokinase, lactate dehydrogenase, gamma glutamyl transpeptidase and aspartate transaminase activity. The activity of these enzymes in the serum may be enhanced by leakage from damaged blood vessels.

O. M. Mahmoud; E. J. H. Ford

1988-01-01

95

3D simulations of early blood vessel formation  

Microsoft Academic Search

Blood vessel networks form by spontaneous aggregation of individual cells migrating toward vascularization sites (vasculogenesis). A successful theoretical model of two-dimensional experimental vasculogenesis has been recently proposed, showing the relevance of percolation concepts and of cell cross-talk (chemotactic autocrine loop) to the understanding of this self-aggregation process. Here we study the natural 3D extension of the computational model proposed earlier,

F. Cavalli; A. Gamba; G. Naldi; M. Semplice; D. Valdembri; G. Serini

2007-01-01

96

Optical-resolution photoacoustic microscopy for imaging blood vessels in vivo  

NASA Astrophysics Data System (ADS)

An optical-resolution photoacoustic microscopy system was designed and fabricated by integration of a two-dimensional scanning galvanometer, an objective lens, an unfocused ultrasound transducer and a sample stage for imaging blood vessels in vivo. In vivo blood vessels of mouse ear were clearly shown and the injured blood vessels were also monitored. The experimental results demonstrate that galvanometer-based photoacoustic microscopy holds clinical potential in detecting lesion of blood vessels.

Yuan, Yi

2012-12-01

97

Computational study of pulsatile blood flow in prototype vessel geometries of coronary segments.  

PubMed

The spatial and temporal distributions of wall shear stress (WSS) in prototype vessel geometries of coronary segments are investigated via numerical simulation, and the potential association with vascular disease and specifically atherosclerosis and plaque rupture is discussed. In particular, simulation results of WSS spatio-temporal distributions are presented for pulsatile, non-Newtonian blood flow conditions for: (a) curved pipes with different curvatures, and (b) bifurcating pipes with different branching angles and flow division. The effects of non-Newtonian flow on WSS (compared to Newtonian flow) are found to be small at Reynolds numbers representative of blood flow in coronary arteries. Specific preferential sites of average low WSS (and likely atherogenesis) were found at the outer regions of the bifurcating branches just after the bifurcation, and at the outer-entry and inner-exit flow regions of the curved vessel segment. The drop in WSS was more dramatic at the bifurcating vessel sites (less than 5% of the pre-bifurcation value). These sites were also near rapid gradients of WSS changes in space and time - a fact that increases the risk of rupture of plaque likely to develop at these sites. The time variation of the WSS spatial distributions was very rapid around the start and end of the systolic phase of the cardiac cycle, when strong fluctuations of intravascular pressure were also observed. These rapid and strong changes of WSS and pressure coincide temporally with the greatest flexion and mechanical stresses induced in the vessel wall by myocardial motion (ventricular contraction). The combination of these factors may increase the risk of plaque rupture and thrombus formation at these sites. PMID:20400349

Chaniotis, A K; Kaiktsis, L; Katritsis, D; Efstathopoulos, E; Pantos, I; Marmarellis, V

2010-04-18

98

Regulation of Blood Vessel versus Lymphatic Vessel Growth in the Cornea  

PubMed Central

Purpose In the present study, the authors developed novel models to stimulate blood vessel formation (hemangiogenesis) versus lymphatic vessel formation (lymphangiogenesis) in the cornea. Methods Micropellets loaded with high-dose (80 ng) or low-dose (12.5 ng) basic fibroblast growth factor (bFGF) were placed in BALB/c corneas. Angiogenic responses were analyzed by immunohistochemistry to quantify blood neovessels (BVs) and lymphatic neovessels (LVs) to 3 weeks after implantation. Areas covered by BV and LV were calculated and expressed as a percentage of the total corneal area (percentage BV and percentage LV). Hemangiogenesis (HA) and lymphangiogenesis (LA) were also assessed after antibody blockade of VEGFR-2 or VEGFR-3 Results Although high-dose bFGF stimulation induced a more potent angiogenic response, the relative LV (RLV = percentage LV/percentage BV × 100) was nearly identical with high- and low-doses of bFGF. Delayed LA responses induced 3 weeks after implantation of high-dose bFGF resulted in a lymphatic vessel-dominant phenotype. Interestingly, the blockade of VEGFR-2 significantly suppressed BV and LV. However, the blockade of VEGFR-3 inhibited only LV (P = 0.0002) without concurrent inhibition of BV (P = 0.79), thereby resulting in a blood vessel-dominant phenotype Conclusions An HA-dominant corneal phenotype can be obtained in BALB/c mice 2 weeks after implantation of an 80-ng bFGF micropellet with VEGFR-3 blockade. Alternatively, an LA-dominant corneal phenotype can be obtained 3 weeks after implantation of an 80-ng bFGF micropellet without supplementary modulating agents. These models will be useful in evaluating the differential contribution of BV and LV to a variety of corneal abnormalities, including transplant rejection, wound healing and microbial keratitis.

Chung, Eui-Sang; Saban, Daniel R.; Chauhan, Sunil K.; Dana, Reza

2009-01-01

99

Scanning electron microscopy of irradiated recipient blood vessels in head and neck free flaps  

SciTech Connect

Irradiated and control recipient blood vessels in a similar patient population were studied with scanning electron microscopy. The vessels that were biopsied were then anastomosed to a free flap. Irradiated arteries display a significantly greater wall thickness and higher incidence of intimal dehiscence compared with control arteries. Fibrin deposition, microthrombi, and endothelium cell dehiscence are present more frequently in irradiated vessels than in control vessels. Details of the preparation and anastomotic technique for irradiated blood vessels are discussed. Microvascular surgery in irradiated human blood vessels carries with it a higher risk of thrombosis due to preexisting vessel wall damage. This risk can be minimized by experience and attention to detail.

Guelinckx, P.J.; Boeckx, W.D.; Fossion, E.; Gruwez, J.A.

1984-08-01

100

Blood flow in major blood vessels-modeling and experiments.  

PubMed

Although primarily motivated by an interest in atherosclerosis, modeling of arterial blood flow is also important to an understanding of congenital effects and to improvements in therapeutics. A variety of methods are available to estimate the flow field in living arteries, each with its own advantages and limitations. Tradeoffs must be made among the realism of the technique, spatial resolution, geometric fidelity, and the reliability of assumed wall mechanical properties. Once the velocity field is obtained, each differentiation, to obtain wall shear or its spatial or temporal derivatives, adds additional uncertainty into the results, demanding cautious interpretation. A distinction is made between "macro" and "micro" levels of flow structure detail: macro level structure is relatively coarse and more descriptive of the flow field, pressure, and shear distribution than the cellular response; the micro approach tries to relate a more local hemodynamic description to vascular pathology. The applications of each, and the interactions between them, are described. Issues related to these approaches, including the use of clinical data, animal experimentation, the role of cell and organ culture, and in vivo flow measurement, are briefly discussed. The summary closes with a list of recommendations for future developments in this area. PMID:16389517

Friedman, Morton H; Giddens, Don P

2005-12-01

101

Visfatin causes endothelium-dependent relaxation in isolated blood vessels  

Microsoft Academic Search

Visfatin is a novel adipocyte-derived cytokine. We hypothesized that visfatin could directly affect vascular reactivity. To test the hypothesis, effects of visfatin on contraction of isolated blood vessels were examined. In endothelium-intact rat aorta, pretreatment with visfatin (100ng\\/ml, 30min) inhibited noradrenaline (NA; 1nM–1?M)-induced contraction. In NA (100nM)-pre-contracted aorta, visfatin (1–100ng\\/ml) directly induced a relaxation. Although an NG-Nitro-l-arginine methyl ester (300?M,

Hideyuki Yamawaki; Naoko Hara; Muneyoshi Okada; Yukio Hara

2009-01-01

102

The use of excised, pressurized blood vessels to study the physiology of vascular smooth muscle  

Microsoft Academic Search

constriction. Such a mechanism may need to operate with some precision as blood flow is a high power function of the internal radius of a blood vessel. Precise control may be particularly important for those vessels which play a major role in regulating the peripheral resistance or have the capacity to do so. Folkow ~~ believes that the arterial vessels

R. N. Speden

1985-01-01

103

Thrombus Branching and Vessel Curvature are Important Determinants of MCA Trunk Recanalization with Merci Thrombectomy Devices  

PubMed Central

Background Determinants of successful recanalization likely differ for Merci thrombectomy(MT) and intra-arterial pharmacologic fibrinolysis interventions. While the amount of thrombotic material to be digested is an important consideration for chemical lysis, mechanical debulking may be more greatly influenced by other target lesion characteristics. Methods In consecutive acute ischemic stroke patients treated with MT for middle cerebral artery M1 occlusions, we analyzed the influence on recanalization success and clinical outcome of target thrombus size (length) and shape (curvature and branching) on pretreatment T2* gradient echo magnetic resonance imaging (MRI). Results Among 65 patients, pretreatment MRI showed susceptibility vessel signs (SVS) in 45 (69%). Thrombus length averaged 13.03 mm (range 5.56–34.91) and irregular shape (curvature or branching) was present in 17/45 (38%). Presence and length of SVS did not predict recanalization or good clinical outcome. Substantial recanalization (TICI 2b or 3) and good clinical outcome (mRS ?2) were more frequent with regular than irregular SVS shape (57% vs 18%, P=0.013; 39% vs 6%, P=0.017). On multiple regression analysis, the only independent predictor of substantial recanalization was irregular SVS (OR, 0.16; 95% CI, 0.04 to 0.69; P=0.014); and leading predictors of good clinical outcome were baseline NIHSS (OR, 1.20; 95% CI, 1.03 to 1.40; P= 0.019) and irregular SVS (OR, 9.36; 95% CI, 0.98 to 89.4; P=0.052). Conclusions Extension thrombus into MCA division branches and curving shape of the MCA stem, but not thrombus length, decrease technical and clinical success of Merci thrombectomy in M1 occlusions.

Zhu, Liangfu; Liebeskind, David S.; Jahan, Reza; Starkman, Sidney; Salamon, Noriko; Duckwiler, Gary; Vinuela, Fernando; Tateshima, Satoshi; Gonzalez, Nestor; Villablanca, Pablo; Ali, Latisha K.; Kim, Doojin; Ovbiagele, Bruce; Froehler, Michael; Tenser, Matthew; Saver, Jeffrey L.

2012-01-01

104

Lama1 mutations lead to vitreoretinal blood vessel formation, persistence of fetal vasculature, and epiretinal membrane formation in mice  

PubMed Central

Background Valuable insights into the complex process of retinal vascular development can be gained using models with abnormal retinal vasculature. Two such models are the recently described mouse lines with mutations in Lama1, an important component of the retinal internal limiting membrane (ILM). These mutants have a persistence of the fetal vasculature of vitreous (FVV) but lack a primary retinal vascular plexus. The present study provides a detailed analysis of astrocyte and vascular development in these Lama1 mutants. Results Although astrocytes and blood vessels initially migrate into Lama1 mutant retinas, both traverse the peripapillary ILM into the vitreous by P3. Once in the vitreous, blood vessels anastomose with vessels of the vasa hyaloidea propria, part of the FVV, and eventually re-enter the retina where they dive to form the inner and outer retinal capillary networks. Astrocytes continue proliferating within the vitreous to form a dense mesh that resembles epiretinal membranes associated with persistent fetal vasculature and proliferative vitreoretinopathy. Conclusions Lama1 and a fully intact ILM are required for normal retinal vascular development. Mutations in Lama1 allow developing retinal vessels to enter the vitreous where they anastomose with vessels of the hyaloid system which persist and expand. Together, these vessels branch into the retina to form fairly normal inner retinal vascular capillary plexi. The Lama1 mutants described in this report are potential models for studying the human conditions persistent fetal vasculature and proliferative vitreoretinopathy.

2011-01-01

105

Vessel Segmentation Using a Shape Driven Flow  

Microsoft Academic Search

We present a segmentation method for vessels using an im- plicit deformable model with a soft shape prior. Blood vessels are chal- lenging structures to segment due to their branching and thinning geome- try as well as the decrease in image contrast from the root of the vessel to its thin branches. Using image intensity alone to deform a model

Delphine Nain; Anthony J. Yezzi; Greg Turk

2004-01-01

106

The architecture of internal blood vessels in human fetal vertebral bodies  

PubMed Central

The internal vascular system of vertebral bodies was investigated in 17–24 wk human fetuses by acrylic dye injection and by corrosion casting/scanning electron microscopy. The regions of intervertebral spaces did not contain blood vessels. The radial metaphyseal vessels were at the stage of centripetal ingrowth into the vertebral body cartilage and their terminal, blindly ending segments had a form of cuff-like capillary plexuses. The anterolateral equatorial arteries communicating with the vessels of the ossification centre were only rarely found. The centre was usually supplied by 2 posterior (nutrient) arteries which branched into an arcade-like array of arterioles equipped with occasional sphincters and giving origin to a dense network of peripherally located capillaries. Numerous blind capillary buds formed the advancing border of the ossification centre. The veins usually accompanied the arteries. In the ossification centre the venous compartment consisted of sinuses drained by larger posterior veins. In the 17 wk fetus, an axial avascular area was observed in the place of notochord localisation, indicating the formation of a ring-shaped ossification centre around the notochord remnants at earlier stages of fetal development.

SKAWINA, A.; LITWIN, J. A.; GORCZYCA, J.; MIODONSKI, A. J.

1997-01-01

107

Tissue Engineering of Ovine Aortic Blood Vessel Substitutes Using Applied Shear Stress and Enzymatically Derived Vascular Smooth Muscle Cells  

Microsoft Academic Search

Compared to native blood vessels, all clinically available blood vessel substitutes perform suboptimally. Numerous approaches to tissue engineer (TE) blood vessels have been pursued using different scaffold materials, cell types, and culture conditions. Several limitations however remain to be overcome prior to the potential application in the arterial system. This study aimed at tissue engineering viable ovine blood vessels suitable

F. Opitz; K. Schenke-Layland; W. Richter; D. P. Martin; I. Degenkolbe; Th. Wahlers; U. A. Stock

2004-01-01

108

Electrokinetic effect of the endothelial glycocalyx layer on two-phase blood flow in small blood vessels  

Microsoft Academic Search

Blood flow behaves differently at the microvascular level than they do at upper levels of circulating systems. The endothelial glycocalyx layer on the luminal surface of blood vessels plays a significant role in regulating blood flow and blood cell movement in microvascular networks. For instance, previous experimental studies showed that the endothelial glycocalyx layer causes additional resistance to blood flow

Mei Liu; Jun Yang

2009-01-01

109

Heterogeneity of muscarinic receptor subtypes in cerebral blood vessels  

SciTech Connect

The identity and distribution of muscarinic cholinergic receptor subtypes and associated signal transduction mechanisms was characterized for the cerebral circulation using correlated functional and biochemical investigations. Subtypes were distinguished by the relative affinities of a panel of muscarinic antagonists, pirenzepine, AF-DX 116 (11-2-((2-(diethylaminomethyl)- 1-piperidinyl)acetyl)-5,11-dihydro-6H- pyrido(2,3-b)(1,4)benzodiazepine-6-one), hexahydrosiladifenidol, methoctramine, 4-diphenylacetoxy-N-methylpiperidine methobromide, dicyclomine, para-fluoro-hexahydrosiladifenidol and atropine. Muscarinic receptors characterized by inhibition of (3H)quinuclidinylbenzilate binding in membranes of bovine pial arteries were of the M2 subtype. In contrast pharmacological analysis of (3H)-quinuclidinylbenzilate binding in bovine intracerebral microvessels suggests the presence of an M4 subtype. Receptors mediating endothelium-dependent vasodilation in rabbit pial arteries were of the M3 subtype, whereas muscarinic receptors stimulating endothelium-independent phosphoinositide hydrolysis in bovine pial arteries were of the M1 subtype. These findings suggest that characteristics of muscarinic receptors in cerebral blood vessels vary depending on the type of vessel, cellular location and function mediated.

Garcia-Villalon, A.L.; Krause, D.N.; Ehlert, F.J.; Duckles, S.P. (Department of Pharmacology, College of Medicine, University of California, Irvine (USA))

1991-07-01

110

Occurrence and function of cyclic nucleotides in blood vessels.  

PubMed

The literature concerned with studies of the occurrence and function of the cyclic nucleotides in blood vessels is reviewed. Emphasis is placed on the critical evaluation of the evidence which relates to the hypothesis that cyclic nucleotides meditate the effects of drugs and neurotransmitters on vascular contractility. The hypothesis that cyclic AMP mediates vasodilation, especially that induced by beta-adrenergic relaxation, is supported by many experimental approaches, but it is concluded that the evidence remains unconvincing based on the criteria established for such a mediator role. Possible sites of action of cyclic AMP are discussed. The demonstrated action of cyclic AMP on vascular membrane electrophysiology and calcium ion pumps are reviewed as possible causes of relaxation. The role of both nucleotides in vascular disease, especially hypertension is discussed. Finally the needs for further research in this area are suggested. PMID:174765

Namm, D H; Leader, J P

1976-01-01

111

Illustration of the heart and blood vessels in medieval times.  

PubMed

Throughout history, illustrations had played a key role in the promotion and evolution of medicine by providing a medium for transmission of scientific observations. Due to religious prohibitions, color drawings of the human body did not appear in medieval Persia and during the Islamic Golden Age. This tradition, however, has been overlooked with the publication of the first color atlas and text of human anatomy, Tashrihi Mansuri (Mansur's Anatomy), by Mansur ibn Ilyas in the fourteenth century AD. Written in Persian and containing several vivid illustrations of the human body, this book gained widespread attention by both scholars and lay persons. In this article, a brief history of Mansur's Anatomy and an English translation of selected sections from this book regarding the heart and blood vessels are presented. PMID:20060606

Khalili, Majid; Shoja, Mohammadali M; Tubbs, R Shane; Loukas, Marios; Alakbarli, Farid; Newman, Andrew J

2010-01-08

112

Migraine aura pathophysiology: the role of blood vessels and microembolisation  

PubMed Central

Migraine attacks with auras are sometimes associated with underlying hereditary or acquired cerebrovascular disorders. A unifying pathophysiological explanation linking migraine to these conditions has been diffcult to identify. On the basis of genetic and epidemiological evidence, we suggest that changes in blood vessels, hypoperfusion disorders, and microembolisation can cause neurovascular dysfunction and evoke cortical spreading depression, an event that is widely thought to underlie aura symptoms. In fact, recent experimental data have indicated that focal, mild, and transient ischaemia can trigger cortical spreading depression without an enduring tissue signature. Although migraine with aura has many causes (eg, neuronal network excitability), it seems that migraine and stroke might both be triggered by hypoperfusion and could therefore exist on a continuum of vascular complications in a subset of patients who have these hereditary or acquired comorbid vascular conditions.

Dalkara, Turgay; Nozari, Ala; Moskowitz, Michael A

2010-01-01

113

Effects of Temperature on Responses of Fresh and Refrigerated Perfused Blood Vessels.  

National Technical Information Service (NTIS)

Effects of temperature change on flow through and drug-induced responses of dog femoral artery branches were studied in vessels freshly excised or refrigerated at 6C for 24 hr. Flow through fresh vessels at 37C did not change significantly as temperature ...

J. C. Murphy O. Carrier J. Sahadi

1972-01-01

114

Measurement of blood vessel characteristics for disease detection based on cone-beam CT images  

SciTech Connect

This paper presents a method of measurement of blood vessel characteristics for disease detection based on cone-beam CT images. The important objective here is to show how representation of blood vessel morphology can lead to feature measurement and identification of abnormal regions. The authors represent the blood vessel surface through curvatures and then measure the surface characteristics that emphasize disease such as aneurysm and stenosis. From results of an application to a patient`s abdominal blood vessels containing two aneurysms and one stenosis, the authors show the feasibility of their method to direct the physician`s attention to the location of the abnormality.

Kawata, Yoshiki; Niki, Noboru [Univ. of Tokushima (Japan). Dept. of Optical Science and Technology; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan). Dept. of Radiology

1996-12-01

115

Matched filter estimation of serial blood vessel diameters from video images  

Microsoft Academic Search

A method for making a contiguous series of blood vessel diameter estimates from digitized images is proposed. It makes use of a vessel intensity profile model based on the vessel geometry and the physics of the imaging process, providing estimates of far greater accuracy than previously obtained. A variety of techniques are used to reduce the computational demand. The method

Frank P. Miles; Alfred L. Nuttall

1993-01-01

116

Heterogeneity of malignant non-Hodgkin lymphoma-associated blood vessels.  

PubMed

The present study described for the first time a high heterogeneity of blood vessels in non-Hodgkin lymphomas (nHL). The tumor blood vessels were highlighted with CD105÷smooth muscle actin (SMA) and CD34/SMA double immunostaining. For both follicular and diffuse types of lymphomas, more than 85% of CD34/SMA positive vessels were of immature and intermediate type. A percent of 96.54 from CD105/SMA assessed blood vessels were of activated and mature activated types with high expression of CD105 on endothelial cells of newly formed blood vessels. Our results suggest that these types of vessels are potential therapeutic targets for antivascular therapy. PMID:23303022

Du?e, Adina Octavia; Ceau?u, Raluca Amalia; Cîmpean, Anca Maria; Ioni??, Hortensia; Raica, M; Gaje, Pu?a

2012-01-01

117

Imaging tissue engineered blood vessel mimics with optical coherence tomography  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT) is a technology that enables 2D cross-sectional images of tissue microstructure. This interferometric technique provides resolutions of approximately 10-20 mum with a penetration depth of 1-2 mm in highly scattering tissues. With the use of fiber optics, OCT systems have been developed for intravascular imaging with a demonstrated improvement in both resolution and dynamic range compared to commercial intravascular ultrasound systems. OCT studies of normal, atherosclerotic, and stented arteries indicate the ability of OCT to visualize arterial structures. These results suggest OCT may be a valuable tool for studying luminal structures in tissue engineered constructs. In the present study, new endoscopic OCT systems and analysis techniques were developed to visualize the growth and response of the cellular lining within a tissue engineered blood vessel mimic (BVM). The BVM consists of two primary components. A biocompatible polymeric scaffold is used to form the tubular structure. Human microvessel cells from adipose tissue are sodded on to the inner surface of the scaffold. These constructs are then developed and imaged within a sterile bioreactor. Three specific aims were defined for the present study. First, an OCT longitudinal scanning endoscope was developed. With this endoscope, a study of 16 BVMs was performed comparing images from OCT and corresponding histological sections. The study demonstrated that endoscopic imaging did not visually damage the mimic cellular lining. OCT images showed excellent correlation with corresponding histological sections. Second, a concentric three element endoscope was developed to provide radial cross-sections of the BVM. OCT images using this endoscope monitored lining development on three types of polymeric scaffolds. In the third specific aim, automated algorithms were developed to assess the percent cellular coverage of a stent using volumetric OCT images. The results of the present study suggest that OCT endoscopic systems may be a valuable tool for assessing and optimizing the development of tissue engineered constructs. Conversely, the BVMs modeled the arterial response to deployed stents allowing the development of automated OCT analysis software. These results suggest that blood vessel mimics may be used to advance OCT technology and techniques.

Bonnema, Garret Thomas

118

Detection of blood vessels in retinal images using two-dimensional matched filters  

Microsoft Academic Search

Blood vessels usually have poor local contrast, and the application of existing edge detection algorithms yield results which are not satisfactory. An operator for feature extraction based on the optical and spatial properties of objects to be recognized is introduced. The gray-level profile of the cross section of a blood vessel is approximated by a Gaussian-shaped curve. The concept of

SUBHASIS CHAUDHURI; SHANKAR CHATTERJEE; NORMAN KATZ; MARK NELSON; MICHAEL GOLDBAUM

1989-01-01

119

Matrix Metalloproteinases in Blood Vessel Development in Human Fetal Skin and in Cutaneous Tumors  

Microsoft Academic Search

In vitro angiogenesis models suggest that new blood vessel formation requires the induction and secretion by endothelial cells of matrix metalloproteinases. These enzymes assist in the controlled proteolytic degradation of the surrounding extracellular matrix during blood vessel formation. The results of in vitro studies cannot be extrapolated directly to the process of in vivo angiogenesis because the type of matrix

Tatiana V. Karelina; Gregory I. Goldberg; Arthur Z. Eisen

1995-01-01

120

Simple and noninvasive analysis of the pulse wave for blood vessel evaluation  

Microsoft Academic Search

The pulse wave is a good indicator to evaluate the viscoelastic properties of blood vessels. The wave is composed of an incident wave and a reflected wave. Since the reflected wave is generated by the reflection of the incident wave at the peripheral artery after propagating long distance along blood vessels, the characteristics of that wave depend remarkably on arterial

Masashi Saito; Yuya Yamamoto; Mami Matsukawa; Yoshiaki Watanabe; Mio Furuya; Takaaki Asada

2009-01-01

121

An efficient blood vessel detection algorithm for retinal images using local entropy thresholding  

Microsoft Academic Search

This paper presents an efficient method for automatic detection and extraction of blood vessels in retinal images. Specifically, we also delineate vascular intersections\\/crossovers. The proposed algorithm is composed of four steps: matched filtering, local entropy thresholding, length filtering, and vascular intersection detection. The purpose of matched filtering is to enhance the blood vessels. Entropy-based thresholding can well keep the spatial

Thitiporn Chanwimaluang; Guoliang Fan

2003-01-01

122

Segmentation of blood vessels from red-free and fluorescein retinal images  

Microsoft Academic Search

The morphology of the retinal blood vessels can be an important indicator for diseases like diabetes, hypertension and retinopathy of prematurity (ROP). Thus, the measurement of changes in morphology of arterioles and venules can be of diagnostic value. Here we present a method to automatically segment retinal blood vessels based upon multiscale feature extraction. This method overcomes the problem of

M. Elena Martínez-Pérez; Alun D. Hughes; Simon A. Thom; Anil A. Bharath; Kim H. Parker

2007-01-01

123

An in vivo assay to test blood vessel permeability.  

PubMed

This method is based on the intravenous injection of Evans Blue in mice as the test animal model. Evans blue is a dye that binds albumin. Under physiologic conditions the endothelium is impermeable to albumin, so Evans blue bound albumin remains restricted within blood vessels. In pathologic conditions that promote increased vascular permeability endothelial cells partially lose their close contacts and the endothelium becomes permeable to small proteins such as albumin. This condition allows for extravasation of Evans Blue in tissues. A healthy endothelium prevents extravasation of the dye in the neighboring vascularized tissues. Organs with increased permeability will show significantly increased blue coloration compared to organs with intact endothelium. The level of vascular permeability can be assessed by simple visualization or by quantitative measurement of the dye incorporated per milligram of tissue of control versus experimental animal/tissue. Two powerful aspects of this assay are its simplicity and quantitative characteristics. Evans Blue dye can be extracted from tissues by incubating a specific amount of tissue in formamide. Evans Blue absorbance maximum is at 620 nm and absorbance minimum is at 740 nm. By using a standard curve for Evans Blue, optical density measurements can be converted into milligram dye captured per milligram of tissue. Statistical analysis should be used to assess significant differences in vascular permeability. PMID:23524912

Radu, Maria; Chernoff, Jonathan

2013-03-16

124

Energy Analysis of Flow Induced Harmonic Motion in Blood Vessel Walls  

Microsoft Academic Search

Energy is transferred between the flowing blood and the vessel walls during pulsatile blood flow (a normal pulse cycle) resulting in storage and dissipation of elastic energy. This allows the elastic and muscular arteries to act as an auxiliary pump to propel the blood fluid forward during systole and maintain a basal blood pressure during diastole. The pulsatile flow pattern

Istvan Horvath; David J. Foran; Frederick H. Silver

2005-01-01

125

Numerical investigation of the non-Newtonian blood flow in a bifurcation model with a non-planar branch.  

PubMed

The non-Newtonian fluid flow in a bifurcation model with a non-planar daughter branch is investigated by using finite element method to solve the three-dimensional Navier-Stokes equations coupled with a non-Newtonian constitutive model, in which the shear thinning behavior of the blood fluid is incorporated by the Carreau-Yasuda model. The objective of this study is to investigate the influence of the non-Newtonian property of fluid as well as of curvature and out-of-plane geometry in the non-planar daughter vessel on wall shear stress (WSS) and flow phenomena. In the non-planar daughter vessel, the flows are typified by the skewing of the velocity profile towards the outer wall, creating a relatively low WSS at the inner wall. In the downstream of the bifurcation, the velocity profiles are shifted towards the flow divider. The low WSS is found at the inner walls of the curvature and the lateral walls of the bifurcation. Secondary flow patterns that swirl fluid from the inner wall of curvature to the outer wall in the middle of the vessel are also well documented for the curved and bifurcating vessels. The numerical results for the non-Newtonian fluid and the Newtonian fluid with original Reynolds number and the corresponding rescaled Reynolds number are presented. Significant difference between the non-Newtonian flow and the Newtonian flow is revealed; however, reasonable agreement between the non-Newtonian flow and the rescaled Newtonian flow is found. Results of this study support the view that the non-planarity of blood vessels and the non-Newtonian properties of blood are an important factor in hemodynamics and may play a significant role in vascular biology and pathophysiology. PMID:15519598

Chen, Jie; Lu, Xi-Yun

2004-12-01

126

Primo Vascular System Accompanying a Blood Vessel from Tumor Tissue and a Method to Distinguish It from the Blood or the Lymph System  

PubMed Central

A primo vessel was observed in the abdominal cavity in the lung cancer mouse model, and its function as an extra metastatic path was observed. In this work, we found a primo vessel accompanying a blood vessel emanating from a tumor in the skin. We also presented simple and efficient criteria to distinguish a primo vessel from a blood or a lymph vessel and from a nerve. The criteria for using DAPI and Phalloidin will be useful in clinical situations to find and identify the primo vessels among the blood vessels, lymph vessels, or nerves in the tissue surrounding a tumor such as a melanoma or breast cancer.

Lim, Jaekwan; Lee, Sungwoo; Su, Zhendong; Kim, Hong Bae; Yoo, Jung Sun; Soh, Kwang-Sup; Kim, Sungchul; Ryu, Yeon Hee

2013-01-01

127

Over-expression of Slit2 induces vessel formation and changes blood vessel permeability in mouse brain  

Microsoft Academic Search

Aim:To investigate the effect of the axon guidance cue Slit2 on the density of blood vessels and permeability of the blood-brain barrier in mouse brain.Methods:hSlit2 transgenic mouse line was constructed, and the phenotypes of the mice were compared with wild-type mice in respect to the lateral ventricle (LV), ventricle pressure, and the choroids plexus. An in vivo Miles permeability assay

Hai-xiong Han; Jian-guo Geng

2011-01-01

128

Use of the descending branch of the lateral femoral circumflex vessels as a composite interposition graft in lower extremity reconstruction.  

PubMed

The prevailing treatment for distal third lower extremity defects is with autologous free tissue transfers. In the trauma patient, these reconstructions are wrought with challenges, including the selection of appropriate recipient vessels, avoiding the zone of injury, and choosing the appropriate flap for transfer, all while maintaining perfusion to the foot. With distal defects and a large zone of injury, the free flap pedicle may need additional length to cover the defect and reach the recipient vessels without excess tension. The creation of an arteriovenous loop from an autologous vein graft is the usual solution. We present a case where additional pedicle length was needed to have a free flap completely cover a distal leg defect and connect to the anterior tibial vessels proximally. The saphenous vein was not available as an interposition graft; therefore, the descending branch of the lateral femoral circumflex artery and venae comitantes were used as a composite arteriovenous interposition graft. PMID:21400580

Echo, Anthony; Bullocks, Jamal M

2011-02-23

129

Personal identification based on blood vessels of retinal fundus images  

NASA Astrophysics Data System (ADS)

Biometric technique has been implemented instead of conventional identification methods such as password in computer, automatic teller machine (ATM), and entrance and exit management system. We propose a personal identification (PI) system using color retinal fundus images which are unique to each individual. The proposed procedure for identification is based on comparison of an input fundus image with reference fundus images in the database. In the first step, registration between the input image and the reference image is performed. The step includes translational and rotational movement. The PI is based on the measure of similarity between blood vessel images generated from the input and reference images. The similarity measure is defined as the cross-correlation coefficient calculated from the pixel values. When the similarity is greater than a predetermined threshold, the input image is identified. This means both the input and the reference images are associated to the same person. Four hundred sixty-two fundus images including forty-one same-person's image pairs were used for the estimation of the proposed technique. The false rejection rate and the false acceptance rate were 9.9×10-5% and 4.3×10-5%, respectively. The results indicate that the proposed method has a higher performance than other biometrics except for DNA. To be used for practical application in the public, the device which can take retinal fundus images easily is needed. The proposed method is applied to not only the PI but also the system which warns about misfiling of fundus images in medical facilities.

Fukuta, Keisuke; Nakagawa, Toshiaki; Hayashi, Yoshinori; Hatanaka, Yuji; Hara, Takeshi; Fujita, Hiroshi

2008-04-01

130

A Computational Model Predicting Disruption of Blood Vessel Development  

PubMed Central

Vascular development is a complex process regulated by dynamic biological networks that vary in topology and state across different tissues and developmental stages. Signals regulating de novo blood vessel formation (vasculogenesis) and remodeling (angiogenesis) come from a variety of biological pathways linked to endothelial cell (EC) behavior, extracellular matrix (ECM) remodeling and the local generation of chemokines and growth factors. Simulating these interactions at a systems level requires sufficient biological detail about the relevant molecular pathways and associated cellular behaviors, and tractable computational models that offset mathematical and biological complexity. Here, we describe a novel multicellular agent-based model of vasculogenesis using the CompuCell3D (http://www.compucell3d.org/) modeling environment supplemented with semi-automatic knowledgebase creation. The model incorporates vascular endothelial growth factor signals, pro- and anti-angiogenic inflammatory chemokine signals, and the plasminogen activating system of enzymes and proteases linked to ECM interactions, to simulate nascent EC organization, growth and remodeling. The model was shown to recapitulate stereotypical capillary plexus formation and structural emergence of non-coded cellular behaviors, such as a heterologous bridging phenomenon linking endothelial tip cells together during formation of polygonal endothelial cords. Molecular targets in the computational model were mapped to signatures of vascular disruption derived from in vitro chemical profiling using the EPA's ToxCast high-throughput screening (HTS) dataset. Simulating the HTS data with the cell-agent based model of vascular development predicted adverse effects of a reference anti-angiogenic thalidomide analog, 5HPP-33, on in vitro angiogenesis with respect to both concentration-response and morphological consequences. These findings support the utility of cell agent-based models for simulating a morphogenetic series of events and for the first time demonstrate the applicability of these models for predictive toxicology.

Kleinstreuer, Nicole; Dix, David; Rountree, Michael; Baker, Nancy; Sipes, Nisha; Reif, David; Spencer, Richard; Knudsen, Thomas

2013-01-01

131

Bradykinin enhances sympathetic neurotransmission in rat blood vessels.  

PubMed

Bradykinin evokes endothelium-dependent relaxation in some vascular beds; on the other hand, the possibility has been demonstrated that in certain organs, such as the adrenal medulla or atria, bradykinin may enhance transmitter release from the sympathetic nerves. We hypothesized that bradykinin may also enhance postganglionic sympathetic neurotransmission in blood vessels. To test this hypothesis, we recorded excitatory junction potentials (EJPs), a measure of sympathetic purinergic neurotransmission, in rat mesenteric resistance arteries with a conventional microelectrode technique. EJPs were elicited by repetitive perivascular nerve stimulation (1 Hz, 20 to 50 V, 30 to 60 micros, 11 pulses). In this preparation, bradykinin (10(-7) or 10(-6) mol/L) significantly enhanced the amplitude of EJPs without altering the resting membrane potential. This effect of bradykinin was blocked by Hoe 140, a bradykinin B2 receptor antagonist, but not by des-Arg(9),[Leu(8)]-bradykinin, a bradykinin B1 receptor antagonist. The cyclooxygenase inhibitor indomethacin or NO synthase inhibitor N(G)-nitro-L-arginine did not alter the effect of bradykinin. Captopril, an ACE inhibitor, but not candesartan, an angiotensin II type 1 receptor antagonist, enhanced the action of a low concentration (10(-8) mol/L) of bradykinin on EJPs. These findings suggest that in rat mesenteric resistance arteries, bradykinin enhances sympathetic purinergic neurotransmission, presumably through presynaptic bradykinin B2 receptors. The clinical relevance of the present findings remains unclear; however, the fact that the ACE inhibitor, but not the angiotensin II type 1 receptor antagonist, enhanced the action of bradykinin on sympathetic neurotransmission may warrant further investigation. PMID:11799074

Kansui, Yasuo; Fujii, Koji; Goto, Kenichi; Abe, Isao

2002-01-01

132

Dynamics of vascular branching morphogenesis: The effect of blood and tissue flow  

NASA Astrophysics Data System (ADS)

Vascularization of embryonic organs or tumors starts from a primitive lattice of capillaries. Upon perfusion, this lattice is remodeled into branched arteries and veins. Adaptation to mechanical forces is implied to play a major role in arterial patterning. However, numerical simulations of vessel adaptation to haemodynamics has so far failed to predict any realistic vascular pattern. We present in this article a theoretical modeling of vascular development in the yolk sac based on three features of vascular morphogenesis: the disconnection of side branches from main branches, the reconnection of dangling sprouts (“dead ends”), and the plastic extension of interstitial tissue, which we have observed in vascular morphogenesis. We show that the effect of Poiseuille flow in the vessels can be modeled by aggregation of random walkers. Solid tissue expansion can be modeled by a Poiseuille (parabolic) deformation, hence by deformation under hits of random walkers. Incorporation of these features, which are of a mechanical nature, leads to realistic modeling of vessels, with important biological consequences. The model also predicts the outcome of simple mechanical actions, such as clamping of vessels or deformation of tissue by the presence of obstacles. This study offers an explanation for flow-driven control of vascular branching morphogenesis.

Nguyen, Thi-Hanh; Eichmann, Anne; Le Noble, Ferdinand; Fleury, Vincent

2006-06-01

133

Electrokinetic effect of the endothelial glycocalyx layer on two-phase blood flow in small blood vessels.  

PubMed

Blood flow behaves differently at the microvascular level than they do at upper levels of circulating systems. The endothelial glycocalyx layer on the luminal surface of blood vessels plays a significant role in regulating blood flow and blood cell movement in microvascular networks. For instance, previous experimental studies showed that the endothelial glycocalyx layer causes additional resistance to blood flow in small blood vessels. One of the important facts of the endothelial glycocalyx layer is that this layer is highly negatively charged. The question remains: do these electrostatic charges retard blood flow in small blood vessels according to the electroviscous effect? Here, a theoretical model is proposed to investigate the electrochemical effects of the endothelial glycocalyx layer on two-phase non-Newtonian blood flow in small blood vessels. Results show that electrostatic charges on the endothelial glycocalyx layer induce negligible effect to blood flow. Therefore, we can attribute the cause of additional resistance by the endothelial glycocalyx layer mainly to other mechanisms, such as, the glycocalyx constituted proteins acting as a flow barrier. PMID:19362568

Liu, Mei; Yang, Jun

2009-04-10

134

Laser optical method of visualizing cutaneous blood vessels and its applications in biometry and photomedicine  

NASA Astrophysics Data System (ADS)

We propose and examine a new approach to visualizing a local network of cutaneous blood vessels using laser optical methods for applications in biometry and photomedicine. Various optical schemes of the formation of biometrical information on the architecture of blood vessels of skin tissue are analyzed. We developed an optical model of the interaction of the laser radiation with the biological tissue and a mathematical algorithm of processing of measurement results. We show that, in medicine, the visualization of blood vessels makes it possible to calculate and determine regions of disturbance of blood microcirculation and to control tissue hypoxia, as well as to maintain the local concentration of oxygen at a level necessary for the normal cellular metabolism. We propose noninvasive optical methods for modern photomedicine and biometry for diagnostics and elimination of tissue hypoxia and for personality identification and verification via the pattern of cutaneous blood vessels.

Asimov, M. M.; Asimov, R. M.; Rubinov, A. N.

2011-05-01

135

Hybrid finite element-finite difference method for thermal analysis of blood vessels.  

PubMed

A hybrid finite-difference/finite-element technique for the thermal analysis of blood vessels embedded in perfused tissue has been developed and evaluated. This method provides efficient and accurate solutions to the conjugated heat transfer problem of convection by blood coupled to conduction in the tissue. The technique uses a previously developed 3D automatic meshing method for creating a finite element mesh in the tissue surrounding the vessels, coupled iteratively with a 1-D marching finite difference method for the interior of the vessels. This hybrid technique retains the flexibility and ease of automated finite-element meshing techniques for modelling the complex geometry of blood vessels and irregularly shaped tissues, and speeds the solution time by using a simple finite-difference method to calculate the bulk mean temperatures within all blood vessels. The use of the 1D finite-difference technique in the blood vessels also eliminates the large computer memory requirements needed to accurately solve large vessel network problems when fine FE meshes are used in the interior of vessels. The accuracy of the hybrid technique has been verified against previously verified numerical solutions. In summary, the hybrid technique combines the accuracy and flexibility found in automated finite-element techniques, with the speed and reduction of computational memory requirements associated with the 1D finite-difference technique, something which has not been done before. This method, thus, has the potential to provide accurate, flexible and relatively fast solutions for the thermal analysis of coupled perfusion/blood vessel problems, and large vessel network problems. PMID:10949130

Blanchard, C H; Gutierrez, G; White, J A; Roemer, R B

136

Numerical investigation of hyperelastic wall deformation characteristics in a micro-scale stenotic blood vessel  

NASA Astrophysics Data System (ADS)

Stenosis is the drastic reduction of blood vessel diameter because of cholesterol accumulation in the vessel wall. In addition to the changes in blood flow characteristics, significant changes occur in the mechanical behavior of a stenotic blood vessel. We conducted a 3-D study of such behavior in micro-scale blood vessels by considering the fluid structure interaction between blood flow and vessel wall structure. The simulation consisted of one-way coupled analysis of blood flow and the resulting structural deformation without a moving mesh. A commercial code based on a finite element method with a hyperelastic material model (Neo-Hookean) of the wall was used to calculate wall deformation. Three different cases of stenosis severity and aspect ratios with and without muscles around the blood vessel were considered. The results showed that the wall deformation in a stenotic channel is directly related to stenosis severity and aspect ratio. The presence of muscles reduces the degree of deformation even in very severe stenosis.

Cheema, Taqi Ahmad; Park, Cheol Woo

2013-08-01

137

Estimation of Blood Flow Speed and Vessel Location from Thermal Video  

Microsoft Academic Search

In this paper we present a novel method for estimation of blood flow speed and vessel location from thermal video. The method is based on a bioheat transfer model that reflects the thermo-physiological processes in a skin region proximal to a major vessel. The model assumes the form of a partial differential equation (PDE) with boundary conditions. Initially, we test

Marc Garbey; Arcangelo Merla; Ioannis Pavlidis

2004-01-01

138

Locating the Optical Nerve in a Retinal Image Using the Fuzzy Convergence of the Blood Vessels  

Microsoft Academic Search

We describe an automated method to locate the optic nerve in images of the ocular fundus. Our method uses a novel al- gorithm we call fuzzy convergence to determine the origination of the blood vessel network. We evaluate our method using 31 images of healthy retinas and 50 images of diseased retinas, containing such diverse symptoms as tortuous vessels, choroidal

Adam Hoover; Michael H. Goldbaum

2003-01-01

139

Locating the optic nerve in a retinal image using the fuzzy convergence of the blood vessels  

Microsoft Academic Search

We describe an automated method to locate the optic nerve in images of the ocular fundus. Our method uses a novel algorithm we call fuzzy convergence to determine the origination of the blood vessel network. We evaluate our method using 31 images of healthy retinas and 50 images of diseased retinas, containing such diverse symptoms as tortuous vessels, choroidal neovascularization,

Adam Hoover; Michael Goldbaum

2003-01-01

140

Proliferation but Not Migration Is Associated with Blood Vessels during Development of the Rostral Migratory Stream  

PubMed Central

Blood vessels play a critical role in regulating neural stem cell proliferation and migration. We show here that blood vessels became progressively aligned in the direction of the rostral migratory stream (RMS) from embryonic day 14 to postnatal day 4. Dividing cells revealed by phosphohistone H3+ immunoreactivity were statistically closer to isolectin B4+ blood vessels than predicted by chance in the emerging RMS. The close proximity of blood vessels and H3+ cells was consistent regardless of the age of the RMS and was strikingly similar to the embryonic cerebral cortex. In contrast to the adult RMS, we found no evidence for preferential juxtaposition of migratory doublecortin-positive neuroblasts and vasculature in the neonatal RMS. Our work provides an important framework for understanding the precise mechanism behind regulation of proliferation.

Nie, Kai; Molnar, Zoltan; Szele, Francis G.

2010-01-01

141

Label-free imaging of blood vessel morphology with capillary resolution using optical microangiography.  

PubMed

Several tissue pathologies are correlated with changes in the blood vessel morphology and microcirculation that supplies the tissue. Optical coherence tomography (OCT) is an imaging technique that enables acquiring non-invasive three-dimensional images of biological structures with micrometer resolution. Optical microangiography (OMAG) is a method of processing OCT data which enables visualizing the three-dimensional blood vessel morphology within biological tissues. OMAG has high spatial resolution which allows visualizing single capillary vessels, and does not require the use of contrast agents. The intrinsic optical signals backscattered by the moving blood cells inside blood vessels are used as the contrast for which OMAG images are based on. In this paper, we discuss a brief review of the OMAG theory, and present some examples of applications for this technique. PMID:23256081

Reif, Roberto; Wang, Ruikang K

2012-09-01

142

Label-free imaging of blood vessel morphology with capillary resolution using optical microangiography  

PubMed Central

Several tissue pathologies are correlated with changes in the blood vessel morphology and microcirculation that supplies the tissue. Optical coherence tomography (OCT) is an imaging technique that enables acquiring non-invasive three-dimensional images of biological structures with micrometer resolution. Optical microangiography (OMAG) is a method of processing OCT data which enables visualizing the three-dimensional blood vessel morphology within biological tissues. OMAG has high spatial resolution which allows visualizing single capillary vessels, and does not require the use of contrast agents. The intrinsic optical signals backscattered by the moving blood cells inside blood vessels are used as the contrast for which OMAG images are based on. In this paper, we discuss a brief review of the OMAG theory, and present some examples of applications for this technique.

Reif, Roberto

2012-01-01

143

Numerical Simulation of Non-Newtonian Blood Flow near a Cerebrovascular Branch with an Aneurysm  

Microsoft Academic Search

This study deals with numerical simulation performed on pulsatile blood flow near a typical cerebrovascular branch with an aneurysm. Non-Newtonian properties of the blood is taken into account in this simulation by use of Carreau-Yasuda viscosity model. The aneurysm concerned takes the shape of sphere, this simple geometry being chosen for the sake of wide range of parametric studies. The

Ken-ichi FUNAZAKI; Kazutoyo YAMADA; Goh MAKANURA

144

Hemostasis of punctured blood vessels using high-intensity focused ultrasound  

Microsoft Academic Search

The hemorrhagic complications of vascular injury can be significant. We report on the use of high-intensity focused ultrasound (HIFU) to stop the hemorrhage of punctured blood vessels in pigs. Two HIFU transducers with frequencies of 3.5 and 2.0 MHz, each equipped with a water-filled conical housing, were used. Major blood vessels (femoral artery and vein, axillary artery, carotid artery and

Shahram Vaezy; Roy Martin; Hadi Yaziji; Peter Kaczkowski; George Keilman; Steve Carter; Michael Caps; Emil Y Chi; Michael Bailey; Lawrence Crum

1998-01-01

145

Pilot study on cryogenic heat transfer in biological tissues embedded with large blood vessels  

Microsoft Academic Search

Blood flow through large vessel plays an important role in affecting the temperature profiles of the living tissues under\\u000a cryosurgery. Besides, arresting of blood vessels due to freezing may possibly cause danger to the patient, which needs to\\u000a be considered when operating the cryoprobe. However, such important issues received few attentions in the bioheat field even\\u000a up to date. In

Y. T. Zhang; J. Liu; Y. X. Zhou

2002-01-01

146

Direct labeling and visualization of blood vessels with lipophilic carbocyanine dye DiI  

Microsoft Academic Search

We describe a protocol to rapidly and reliably visualize blood vessels in experimental animals. Blood vessels are directly labeled by cardiac perfusion using a specially formulated aqueous solution containing 1,1?-dioctadecyl-3,3,3?,3?-tetramethylindocarbocyanine perchlorate (DiI), a lipophilic carbocyanine dye, which incorporates into endothelial cell membranes upon contact. By lateral diffusion, DiI also stains membrane structures, including angiogenic sprouts and pseudopodial processes that are

Yiwen Li; Ying Song; Lian Zhao; Gabriel Gaidosh; Alan M Laties; Rong Wen

2008-01-01

147

Peptide-Mediated Targeting to Tumor Blood Vessels of Lung Cancer for Drug Delivery  

Microsoft Academic Search

Antiangiogenesis therapies for the treatment of cancers hold the promise of high efficacy and low toxicity. In vivo phage display was used to identify peptides specifically targeting tumor blood vessels. The peptide SP5-52 recognized tumor neovasculature but not normal blood vessels in severe combined immunodeficiency mice bearing human tumors. Synthetic peptide was shown to inhibit the binding of PC5-52 phage

Tong-Young Lee; Szu-Yao Kuo; De-Kuan Chang; Han-Chung Wu

2007-01-01

148

In vitro and in vivo application of PLGA nanofiber for artificial blood vessel  

Microsoft Academic Search

Poly(lactic-co-glycolic acid) (PLGA) tubes (5 mm in diameter) were fabricated using an electro spinning method and used as a scaffold for\\u000a artificial blood vessels through the hybridization of smooth muscle cells (SMCs) and endothelial cells (ECs) differentiated\\u000a from canine bone marrow under previously reported conditions. The potential clinical applications of these artificial blood\\u000a vessels were investigated using a canine model.

Mi Jin Kim; Ji-Heung Kim; Gijong Yi; Sang-Hyun Lim; You Sun Hong; Dong June Chung

2008-01-01

149

Fibroblasts potentiate blood vessel formation partially through secreted factor TIMP-1  

Microsoft Academic Search

During wound repair, new blood vessels form in response to angiogenic signals emanating from injured tissues. Dermal fibroblasts\\u000a are known to play an important role in wound healing, and have been linked to angiogenesis; therefore, we sought to understand\\u000a the mechanisms through which these cells control blood vessel formation. Using a three-dimensional angiogenesis assay we demonstrate\\u000a that dermal fibroblasts enhance

Hua Liu; Bo Chen; Brenda Lilly

2008-01-01

150

Visualisation of blood and lymphatic vessels with increasing exposure time of the detector  

NASA Astrophysics Data System (ADS)

We describe the laser speckle contrast method for simultaneous noninvasive imaging of blood and lymphatic vessels of living organisms, based on increasing detector exposure time. In contrast to standard methods of fluorescent angiography, this technique of vascular bed imaging and lymphatic and blood vessel demarcation does not employ toxic fluorescent markers. The method is particularly promising with respect to the physiology of the cardiovascular system under in vivo conditions.

Kalchenko, V. V.; Kuznetsov, Yu L.; Meglinski, I. V.

2013-07-01

151

Infrared laser thermal fusion of blood vessels: preliminary ex vivo tissue studies.  

PubMed

Suture ligation of blood vessels during surgery can be time-consuming and skill-intensive. Energy-based, electrosurgical, and ultrasonic devices have recently replaced the use of sutures and mechanical clips (which leave foreign objects in the body) for many surgical procedures, providing rapid hemostasis during surgery. However, these devices have the potential to create an undesirably large collateral zone of thermal damage and tissue necrosis. We explore an alternative energy-based technology, infrared lasers, for rapid and precise thermal coagulation and fusion of the blood vessel walls. Seven near-infrared lasers (808, 980, 1075, 1470, 1550, 1850 to 1880, and 1908 nm) were tested during preliminary tissue studies. Studies were performed using fresh porcine renal vessels, ex vivo, with native diameters of 1 to 6 mm, and vessel walls flattened to a total thickness of 0.4 mm. A linear beam profile was applied normal to the vessel for narrow, full-width thermal coagulation. The laser irradiation time was 5 s. Vessel burst pressure measurements were used to determine seal strength. The 1470 nm laser wavelength demonstrated the capability of sealing a wide range of blood vessels from 1 to 6 mm diameter with burst strengths of 578 ± 154, 530 ± 171, and 426 ± 174? mmHg for small, medium, and large vessel diameters, respectively. Lateral thermal coagulation zones (including the seal) measured 1.0 ± 0.4? mm on vessels sealed at this wavelength. Other laser wavelengths (1550, 1850 to 1880, and 1908 nm) were also capable of sealing vessels, but were limited by lower vessel seal pressures, excessive charring, and/or limited power output preventing treatment of large vessels (>4? mm outer diameter). PMID:23640080

Cilip, Christopher M; Rosenbury, Sarah B; Giglio, Nicholas; Hutchens, Thomas C; Schweinsberger, Gino R; Kerr, Duane; Latimer, Cassandra; Nau, William H; Fried, Nathaniel M

2013-05-01

152

A synthetic model for blood coagulation including blood slip at the vessel wall.  

PubMed

Modeling blood coagulation has taken various directions in recent years, depending on the aspects that authors wish to emphasize. In this paper we want to address an issue that has been systematically ignored in the relevant literature, namely the effect of blood slip at the vessels wall. The presence of a slip results in an increased supply of activated platelets to the clotting site. We calculate such a contribution showing that, in extreme cases, it can be even dominant. Indeed, raising the concentration of activated platelets induces an acceleration of thrombin production and eventually of the whole clot progression. The model explains the difference between arterial and venous thrombi. We confine to the coagulation stage known as "propagation phase" in the context of the so called cell based model. The paper is preparatory for a deeper analysis in which the clotting process is coupled to blood rheology and that will be carried out in the future by the same authors. At the present stage, the extremely complex biochemistry has been simplified adopting a leaner, though virtual, system of diffusion-convection-reaction equations, in the optics of providing "modular" models, that can be reduced or enlarged so to meet specific modeling requirements. PMID:22759407

Fasano, Antonio; Pavlova, Jevgenija; Sequeira, Adélia

2013-01-01

153

Heterogeneity of the tumor vasculature: the need for new tumor blood vessel type-specific targets.  

PubMed

Therapies directed against VEGF-A and its receptors are effective in treating many mouse tumors but have been less so in treating human cancer patients. To elucidate the reasons that might be responsible for this difference in response, we investigated the nature of the blood vessels that appear in human and mouse cancers and the tumor "surrogate" blood vessels that develop in immunodeficient mice in response to an adenovirus expressing VEGF-A(164). Both tumor and tumor surrogate blood vessels are heterogeneous and form by two distinct processes, angiogenesis and arterio-venogenesis. The first new angiogenic blood vessels to form are mother vessels (MV); MV arise from preexisting venules and capillaries and evolve over time into glomeruloid microvascular proliferations (GMP) and subsequently into capillaries and vascular malformations (VM). Arterio-venogenesis results from the remodeling and enlargement of preexisting arteries and veins, leading to the formation of feeder arteries (FA) and draining veins (DV) that supply and drain angiogenic vessels. Of these different blood vessel types, only the two that form first, MV and GMP, were highly responsive to anti-VEGF therapy, whereas "late"-formed capillaries, VM, FA and DV were relatively unresponsive. This finding may explain, at least in part, the relatively poor response of human cancers to anti-VEGF/VEGFR therapies, because human cancers, present for months or years prior to discovery, are expected to contain a large proportion of late-formed blood vessels. The future of anti-vascular cancer therapy may depend on finding new targets on "late" vessels, apart from those associated with the VEGF/VEGFR axis. PMID:22692562

Nagy, Janice A; Dvorak, Harold F

2012-06-13

154

Isolation of high-quality RNA from stented blood vessels.  

PubMed

Stents have become a standard of care for the treatment of coronary artery disease. A series of cellular and molecular processes contribute to the vascular response following stent placement. For the purpose of local gene expression studies, metallic stent struts are usually removed from the vessel wall with forceps under a dissection microscope prior to RNA extraction. Main drawbacks of the manual dissection are that it may cause additional tissue damage and compromise the quality of RNA through prolonged tissue handling. In this technical note, we report the recovery of high-quality RNA from atherosclerotic vessels with stent struts left in situ. PMID:23770293

Van Dyck, Christophe J; Timmermans, Jean-Pierre; Fransen, Erik; Vrints, Christiaan J; Hoymans, Vicky Y

2013-06-12

155

Label free in vivo laser speckle imaging of blood and lymph vessels  

NASA Astrophysics Data System (ADS)

The peripheral lymphatic vascular system is a part of the immune body system comprising a complex network of lymph vessels and nodes that are flowing lymph toward the heart. Traditionally the imaging of lymphatic vessels is based on the conventional imaging modalities utilizing contrast fluorescence materials. Given the important role of the lymphatic system there is a critical need for the development of noninvasive imaging technologies for functional quantitative diagnosis of the lymph vessels and lymph flow without using foreign chemicals. We report a label free methodology for noninvasive in vivo imaging of blood and lymph vessels, using long-exposure laser speckle imaging approach. This approach entails great promise in the noninvasive studies of tissues blood and lymph vessels distribution in vivo.

Kalchenko, Vyacheslav; Kuznetsov, Yuri; Meglinski, Igor; Harmelin, Alon

2012-05-01

156

The cortical representation of shadows cast by retinal blood vessels.  

PubMed Central

PURPOSE: We inquired whether the representation of angioscotomas could be detected in the primary (striate) visual cortex. METHODS: In 12 normal squirrel monkeys, the ocular fundi were photographed and retinal vascular landmarks were projected onto a tangent screen for calibration. Each animal then underwent monocular enucleation under general anesthesia. Animals were perfused after 8 to 10 days, and flat-mounted sections of striate cortex were processed for the metabolic enzyme cytochrome oxidase (CO). RESULTS: In each animal, the cortical region corresponding to the blind spot appeared as a 3 x 2 mm oval in the CO staining pattern. It stood out because it received input from only 1 eye. In 9 of 12 animals, the representation of the major retinal vessels was also visible, for the same reason. In our best examples, CO sections showed about 10 thin lines radiating from the blind spot representation. Some could be traced for 15 mm, all the way to the vertical meridian. Vessels only 12 minutes of arc in diameter were represented in the cortex. Each angioscotoma representation in the cortex could be matched with its corresponding retinal vessel in the fundus. CONCLUSIONS: Our findings show that (1) the visual field map in layer IVc is more precise than indicated by physiological studies, and (2) visual experience must refine the final pattern of geniculocortical projections, given that the retinal vessels can produce a shadow only after birth. Images FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 12

Horton, J C; Adams, D L

2000-01-01

157

Effect of the Blood Vessel Viscoelasticity on Periodic Blood Pressure Wave Propagation  

NASA Astrophysics Data System (ADS)

Clinical arterial stiffness indexes such as PWV (pulse wave velocity) or PP (pulse pressure), which are obtained by analyzing blood pressure pulse waveforms in vivo, are used in the prognosis of cardiovascular diseases and thus analyses of pulse waveform are clinically important. The pulse wave in vivo, however, is complicated because of the complex viscoelastic property of the blood vessel wall. In addition, numerical flow simulations are useful for understanding pulse wave propagation in circulatory systems. Our proposed nonlinear one-dimensional numerical simulation model can accurately simulate the measurements of pressure waves in a silicone rubber tube and indicate that the viscoelasticity of the tube wall was significantly influenced by a single pulse waveform; however, the influence of viscoelasticity change on periodic pulsatile wave propagation has not yet been studied. The purpose of this study was therefore to investigate the effect of viscoelasticity change on the periodic pulsatile wave. For this purpose, we examined the effect of the viscoelasticity of a single silicone tube on periodic pulse wave propagation by comparing the calculated results using a one-dimensional model. As a result, the one-dimensional model could accurately express the experimental results with periodic pulsatile waves. In addition, both PWV and PP increase when the viscoelastic value of the dynamic modulus elasticity ratio increases, because increasing the elastic modulus is more effective than the energy dissipation effect by viscoelasticity change. Consequently, it is necessary to measure the viscoelastic property of the vessel wall accurately in order to estimate the arterial stiffness index (PWV and PP) accurately.

Kitawaki, Tomoki; Shimizu, Masashi

158

Anaphylactic contraction of pulmonary blood vessels of chicken.  

PubMed Central

1 Isolated pulmonary arterial and vein strips from sensitized or non-sensitized chickens exhibited dose-dependent contractions to adrenaline greater than, noradrenaline greater than, 5-hydroxytryptamine greater than, histamine greater than, dopamine. Individual variability in the responsiveness of the vessels to agonists was marked. In general veins were 2 to 25 times more sensitive to agonists than arterial strips. 2 Isoprenaline (a relatively specific beta-adrenoceptor agonist) induced relaxation of the submaximally contracted pulmonary vein and arteries at low doses and contractions at high concentrations. 3 Contractile responses to acetylcholine or carbachol were not regularly recorded; only 50% of the vessels reacted to cholinoceptor agonists over a wide threshold dose range. 4 Chicken pulmonary vessels were found relatively insensitive to bradykinin. 5 Effects of prostaglandins were variable. Prostaglandin F2alpha induced dose-related contractions of the vein and arterial strips; prostglandins E1 and E2 at low doses partially contracted pulmonary artery irrespective of the spasmogen used and further increase in doses induced either no effect or contractions. Prostaglandin E1 induced marked and rapid contractions of the vein. Prostaglandin E2 induced relaxations of the prostaglandin F2alpha-contracted vein only, but produced no effect or slight contractions of the veins partially contracted to other spasmogens. 6 Pulmonary arterial and vein strips obtained from chickens sensitized to horse plasma exhibited Schultz-Dale contractions of variable magnitude and duration to specific antigenic challenge only. In many vessels, antigen-induced contractions were associated with marked increase in spontaneous activity. 7 The importance of the Schultz-Dale reaction in avian pulmonary vessels is discussed in relation to the right heart dilatation associated with anaphylaxis in the chicken.

Chand, N; Eyre, P

1977-01-01

159

Objective assessment of blood and lymphatic vessel invasion and association with macrophage infiltration in cutaneous melanoma  

PubMed Central

The aims of this study were to investigate the role of vascular invasion (blood and lymphatic), vessel density and the presence of tumour-associated macrophages as prognostic markers in 202 cutaneous melanoma patients. Sections of primary melanoma were stained with lymphatic-specific antibody D2-40 to assess lymphatic vessel invasion and density in intratumoural and peritumoural areas; an antibody against endothelial marker CD34 was used to determine blood vessel invasion and density, and an antibody against CD68 was used to determine macrophage counts. Immunohistochemically determined vascular invasion (combined blood and lymphatic) was compared with that determined using haematoxylin and eosin (H&E) staining. The use of immunohistochemistry increased detection of vascular invasion from 8–30% of patients, and histological exam of H&E-stained tissue was associated with a false positive rate of 64%. Lymphatic vessel invasion occurred at a much higher frequency than blood vessel invasion (27 and 4% of patients, respectively). Although immunohistochemically detected vessel invasion was significantly associated with histological markers of adverse prognosis, such as increased Breslow thickness, ulceration and mitotic rate (all P<0.001), no associations with relapse-free or overall survival were observed. High macrophage counts were significantly associated with markers of aggressive disease, such as Breslow thickness, ulceration and mitotic rate (P<0.001, P<0.001, P=0.005, respectively), and lymphatic vessel invasion and high microvessel density (P=0.002 and P=0.003, respectively). These results suggest that vascular invasion is more accurately detected using immunohistochemistry and occurs predominantly via lymphatic vessels. The association of vessel characteristics with histological characteristics of the primary melanoma provides evidence for their biological importance in melanoma, but that they were not associated with clinical outcome attests to the value of existing histological prognostic biomarkers. We note that a high macrophage count may be associated with neovascularisation and primary tumour growth, and may also promote invasion through lymphatic vessels.

Storr, Sarah J; Safuan, Sabreena; Mitra, Angana; Elliott, Faye; Walker, Christopher; Vasko, Mark J; Ho, Bernard; Cook, Martin; Mohammed, Rabab AA; Patel, Poulam M; Ellis, Ian O; Newton-Bishop, Julia A; Martin, Stewart G

2012-01-01

160

Objective assessment of blood and lymphatic vessel invasion and association with macrophage infiltration in cutaneous melanoma.  

PubMed

The aims of this study were to investigate the role of vascular invasion (blood and lymphatic), vessel density and the presence of tumour-associated macrophages as prognostic markers in 202 cutaneous melanoma patients. Sections of primary melanoma were stained with lymphatic-specific antibody D2-40 to assess lymphatic vessel invasion and density in intratumoural and peritumoural areas; an antibody against endothelial marker CD34 was used to determine blood vessel invasion and density, and an antibody against CD68 was used to determine macrophage counts. Immunohistochemically determined vascular invasion (combined blood and lymphatic) was compared with that determined using haematoxylin and eosin (H&E) staining. The use of immunohistochemistry increased detection of vascular invasion from 8-30% of patients, and histological exam of H&E-stained tissue was associated with a false positive rate of 64%. Lymphatic vessel invasion occurred at a much higher frequency than blood vessel invasion (27 and 4% of patients, respectively). Although immunohistochemically detected vessel invasion was significantly associated with histological markers of adverse prognosis, such as increased Breslow thickness, ulceration and mitotic rate (all P<0.001), no associations with relapse-free or overall survival were observed. High macrophage counts were significantly associated with markers of aggressive disease, such as Breslow thickness, ulceration and mitotic rate (P<0.001, P<0.001, P=0.005, respectively), and lymphatic vessel invasion and high microvessel density (P=0.002 and P=0.003, respectively). These results suggest that vascular invasion is more accurately detected using immunohistochemistry and occurs predominantly via lymphatic vessels. The association of vessel characteristics with histological characteristics of the primary melanoma provides evidence for their biological importance in melanoma, but that they were not associated with clinical outcome attests to the value of existing histological prognostic biomarkers. We note that a high macrophage count may be associated with neovascularisation and primary tumour growth, and may also promote invasion through lymphatic vessels. PMID:22080065

Storr, Sarah J; Safuan, Sabreena; Mitra, Angana; Elliott, Faye; Walker, Christopher; Vasko, Mark J; Ho, Bernard; Cook, Martin; Mohammed, Rabab A A; Patel, Poulam M; Ellis, Ian O; Newton-Bishop, Julia A; Martin, Stewart G

2011-11-11

161

Tissue Engineering of Blood Vessels: Functional Requirements, Progress, and Future Challenges  

PubMed Central

Vascular disease results in the decreased utility and decreased availability of autologus vascular tissue for small diameter (< 6 mm) vessel replacements. While synthetic polymer alternatives to date have failed to meet the performance of autogenous conduits, tissue-engineered replacement vessels represent an ideal solution to this clinical problem. Ongoing progress requires combined approaches from biomaterials science, cell biology, and translational medicine to develop feasible solutions with the requisite mechanical support, a non-fouling surface for blood flow, and tissue regeneration. Over the past two decades interest in blood vessel tissue engineering has soared on a global scale, resulting in the first clinical implants of multiple technologies, steady progress with several other systems, and critical lessons-learned. This review will highlight the current inadequacies of autologus and synthetic grafts, the engineering requirements for implantation of tissue-engineered grafts, and the current status of tissue-engineered blood vessel research.

Kumar, Vivek A.; Brewster, Luke P.; Caves, Jeffrey M.; Chaikof, Elliot L.

2012-01-01

162

Evaluation of immunohistochemical markers of lymphatic and blood vessels in canine mammary tumours.  

PubMed

Canine mammary tumours (CMTs) are the most common neoplasms in intact female dogs. Bitches with spontaneously arising CMTs represent a promising animal model for human breast cancer research. The aim of the present study was to develop an immunohistochemical protocol for the identification of blood and lymphatic vessels in CMTs. Antibodies specific for human lymphatic vessels (prox-1, lyve-1, podoplanin and D2-40) and blood vessels (von Willebrand factor [vWf], CD31 and CD34) were utilized. Serial sections of 18 samples (eight samples of normal canine mammary tissue, five benign and five malignant CMTs) were examined. Antibodies specific for podoplanin, D2-40 and CD34 showed no immunoreactivity with canine tissue. Prox-1 and CD31 were determined to be the most suitable markers for lymphatic and blood vessels, respectively. PMID:23123127

Sleeckx, N; Van Brantegem, L; Fransen, E; Van den Eynden, G; Casteleyn, C; Veldhuis Kroeze, E; Van Ginneken, C

2012-11-02

163

An experimental system for the study of ultrasound exposure of isolated blood vessels  

NASA Astrophysics Data System (ADS)

An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and thus vessel functionality), and potential leakage of intraluminal 70 kDa FITC-dextran fluorescence marker. A vessel chamber allowed the mounting of an isolated vessel whilst maintaining its viability, with pressure regulation for the control of intraluminal pressure and induction of flow for the infusion of contrast microbubbles. A fibre-optic hydrophone sensor mounted on the vessel chamber using a micromanipulator allowed pre-exposure targeting of the vessel to within 150 µm, and monitoring of acoustic cavitation emissions during exposures. Acoustic cavitation was also detected using changes in the ultrasound drive voltage and by detection of audible emissions using a submerged microphone. The suitability of this system for studying effects in the isolated vessel model has been demonstrated using a pilot study of 6 sham exposed and 18 high intensity focused ultrasound exposed vessels, with or without intraluminal contrast agent (SonoVue) within the vessels.

Tokarczyk, Anna; Rivens, Ian; van Bavel, E.; Symonds-Tayler, Richard; ter Haar, Gail

2013-04-01

164

Vasodilator effects of ibudilast on retinal blood vessels in anesthetized rats.  

PubMed

Ibudilast (3-isobutyryl-2-isopropylpyrazolo[1,5-alpha]pyridine) is clinically used as a cerebral vasodilator in Japan. However, the effects of ibudilast on retinal blood vessels have not been fully examined. The aim of this study, therefore, was to examine the effects of ibudilast on retinal blood vessels in rats in vivo. Male Wistar rats (8 to 10 weeks old) were anesthetized with thiobutabarbital (120 mg/kg, intraperitoneally (i.p.)). Retinal vascular images were captured with a fundus camera system for small animals, and the diameter of retinal blood vessels was measured. Ibudilast (0.1 and 1 mg/kg, intravenously (i.v.)) elicited a sustained increase in the diameter of retinal blood vessels and heart rate without altering systemic blood pressure. The effects of ibudilast were significantly reduced by treatment with the nonselective cyclooxygenase inhibitor indomethacin (5 mg/kg, i.p.). These results suggest that ibudilast dilates retinal blood vessels through cyclooxygenase-dependent mechanisms in rats in vivo. PMID:19881310

Noguchi, Masahiro; Mori, Asami; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

2009-11-01

165

Noninvasive Measurements and Analysis of Blood Velocity Profiles in Human Retinal Vessels  

PubMed Central

Purpose. To quantitatively model the changes in blood velocity profiles for different cardiac phases in human retinal vessels. Methods. An adaptive optics scanning laser ophthalmoscope (AOSLO) was used to measure blood velocity profiles in three healthy subjects. Blood velocity was measured by tracking erythrocytes moving across a scanning line. From the radial position of the cells within the lumen, the blood velocity profile was computed. The cardiac pulsatility was recorded with a cardiac signal monitor. Results. The shape of the blood velocity profile in retinal arteries changed systematically during the cardiac cycle, with the flattest profile occurring during the diastolic phase. The measured blood velocity profiles were typically flatter than the commonly assumed parabolic shape. The flatness increased with decreasing vessel size. For the large veins (>80 ?m), the ratio of the centerline velocity to the cross-sectional average velocity was between 1.50 and 1.65. This ratio decreased to 1.36 in the smallest vein studied (32 ?m). Velocity profiles downstream from a venous confluence showed two peaks at 120 ?m from the confluence, but a single velocity peak 500 ?m downstream from the confluence. Conclusions. The cardiac cycle influences the blood flow velocity profiles systematically in retinal arteries but not in veins. Parabolic flow was not found in even the largest vessels studied, and deviations from parabolic flow increased in smaller vessels. The measurements are sensitive enough to measure the dual-humped blood velocity profile at a vein confluence.

Zhong, Zhangyi; Song, Hongxin; Chui, Toco Yuen Ping; Petrig, Benno L.

2011-01-01

166

Enhanced permeability of tumor blood vessels in brain using focused ultrasound with microbubbles  

Microsoft Academic Search

Several studies have demonstrated that focused ultrasound (FUS) in the presence of microbubbles is able to temporarily disrupt the blood-brain barrier (BBB) and deliver drugs to the central nervous system. While magnetic resonance- guided FUS (MRgFUS) treatments have shown promising results in targeted drug delivery, one question still remains how much the blood vessel permeability can be enhanced in tumors.

Eun-Joo Park; Yong-Zhi Zhang; Natalia Vykhodtseva; Nathan McDannold

2010-01-01

167

Local blood vessel formation in the human chorion in the early periods of normal pregnancy  

Microsoft Academic Search

Graphic reconstructions were used to study the topographic relations between the blood islets in the stroma of the villi. The special features marking the differentiation of the cells taking part in the formation of the locaI blood vessels in the chorion were studied by B. P. Khvatov's karyometric method [15, 16]. In each case 200 nuclei were drawn from the

A. I. Brusilovskii

1965-01-01

168

Differentiating Blood, Lymph, and Primo Vessels by Residual Time Characteristic of Fluorescent Nanoparticles in a Tumor Model  

PubMed Central

Fluorescent nanoparticles (FNPs) which were injected into a tumor tissue flowed out through the blood and lymph vessels. The FNPs in blood vessels remained only in the order for few minutes while those in lymph vessels remained for a long time disappearing completely in 25 hours. We found a primo vessel inside a lymph vessel near a blood vessel, and FNPs remained in the primo vessel for longer than 25 hours. In addition, we examined in detail the residual time characteristics of lymph vessels because it could be useful in a future study of fluid dynamical comparison of the three conduits. These residual time characteristics of FNPs in the three kinds of vessels may have implications for the dynamics of nanoparticle drugs for cancer chemotherapy.

Lee, Sungwoo; Lim, Jaekwan; Cha, Jinmyung; Lee, Jin-Kyu; Ryu, Yeon Hee; Kim, SungChul; Soh, Kwang-Sup

2013-01-01

169

Optimizing blood vessel contrast in fast three-dimensional MRI.  

PubMed

Magnetic resonance angiography has matured to the point where clinically useful images can be acquired in half an hour or less. In this paper, the role of 3D imaging techniques is primarily considered. Specifically, the optimal imaging parameters, sequences, and reconstruction techniques are evaluated for moving spins. A variant of FISP known as ROAST with low flip angles, short repeat times, and a thick slab has been found to yield the best 3D survey scan of the cranial vessels with roughly 1 X 1 X 1-mm3 resolution in each of the processed images (slices). For the faster flowing carotids, a sagittal scout with as short a TE as possible is required to avoid spin dephasing. Localization is accomplished in both cases by acquiring thin slab 3D, thin partition, larger flip angle, longer repeat time FLASH sequences. Different choices of dephase/rephase sequences and directions are also reviewed. These choices are discussed from a practical and theoretical perspective. In particular, improvements in contrast and resolution are evaluated using half-Fourier, 512 acquisition, small fields of view and constrained reconstruction for both rephased gradient echo sequences and dephased thin slice long TR spin-echo sequences. A resolution of 0.5-0.75 mm is recommended to obtain sufficient image quality for consistent clinical interpretation of stenoses and vessel abnormalities. PMID:2345503

Haacke, E M; Masaryk, T J; Wielopolski, P A; Zypman, F R; Tkach, J A; Amartur, S; Mitchell, J; Clampitt, M; Paschal, C

1990-05-01

170

An improved matched filter for blood vessel detection of digital retinal images.  

PubMed

The matched filter has been widely used in the detection of blood vessels of the human retina digital image. In this paper, the matched filter response to the detection of blood vessels is increased by proposing better filter parameters. These filter parameters are found by using an optimization procedure on 20 retina images of the DRIVE database. Comparisons with other approaches show that the matched filter that uses the newly found parameters outperforms the matched filter that uses the classical filter parameters as well as some vessel detection techniques. A technique is also discussed to find the best threshold value for the continuous matched filter output image and hence the best segmented vessel image. PMID:16697363

Al-Rawi, Mohammed; Qutaishat, Munib; Arrar, Mohammed

2006-05-12

171

An automated algorithm for blood vessel count and area measurement in 2-D choroidal scan images.  

PubMed

We present an automated algorithm for the detection of blood vessels in 2-D choroidal scan images followed by a measurement of the area of the vessels. The objective is to identify vessel parameters in the choroidal stroma that are affected by various abnormalities. The algorithm is divided into five stages. In the first stage, the image is denoised to remove sensor noise and facilitate further processing. In the second stage, the image is segmented in order to find the region of interest. In the third stage, three different contour detection methods are applied to address different challenges in vessel contour. In the fourth stage, the outputs of the three contour detection methods are combined to achieve refined vessel contour detection. In the fifth and final stage, the area of these contours are measured. The results have been evaluated by a practicing opthalmologist and performance of the algorithm relative to expert detection is reported. PMID:24110447

Mahajan, Nagaraj R; Donapati, Ravi Chandra Reddy; Channappayya, Sumohana S; Vanjari, Sivaramakrishna; Richhariya, Ashutosh; Chhablani, Jay

2013-07-01

172

Role of the Wilms’ tumour transcription factor, Wt1, in blood vessel formation  

Microsoft Academic Search

Blood vessel formation is important for normal organ development and tumour growth. A highly specialised developmental program\\u000a of vessel formation exists in the heart and is essential for normal cardiogenesis. From mouse models, it became clear that\\u000a the Wilms’ tumour protein Wt1 is required for normal heart development. Originally identified as a tumour suppressor gene\\u000a based on its mutational inactivation

Holger Scholz; Kay-Dietrich Wagner; Nicole Wagner

2009-01-01

173

Why are tumour blood vessels abnormal and why is it important to know?  

PubMed Central

Tumour blood vessels differ from their normal counterparts for reasons that have received little attention. We report here that they are of at least six distinct types, we describe how each forms, and, looking forward, encourage the targeting of tumour vessel subsets that have lost their vascular endothelial growth factor-A (VEGF-A) dependency and so are likely unresponsive to anti-VEGF-A therapies.

Nagy, J A; Chang, S-H; Dvorak, A M; Dvorak, H F

2009-01-01

174

Physical properties of resistance vessel wall in peripheral blood flow regulation--I. Mathematical model.  

PubMed

A mathematical model is introduced to investigate the influence of the physical properties of the resistance vessel wall on the metabolic and myogenic mechanisms. The resistance vessel wall is assumed to have an elastic property and the elastic modulus to be a function of pressure (myogenic) and flow (metabolic). Blood is Poiseuille's flow. The resulting mathematical equations for pressure-flow, pressure-diameter, pressure-wall tension and pressure-wall elastic modulus relationships introduced obey Laplace's law. Poiseuille's law and Hooke's law. In comparison with the experimental data (pressure diameter), the mathematical model is confirmed to explain well the dynamic behavior of the resistance vessel wall in vivo. PMID:2708390

Iida, N

1989-01-01

175

The mechanisms of blood vessel closure in humans by the application of ultrasonic energy  

Microsoft Academic Search

Background  The use of the ultrasonically activated scalpel (UAS) for vessel closure has attained widespread acceptance in many surgical\\u000a fields. The aim of our study was to investigate the electron microscopic changes to the blood vessels after the application\\u000a of UAS.\\u000a \\u000a \\u000a \\u000a Methods  We collected 10 arterial and 10 venous segments from vessels that had previously been closed by UAS during abdominal operations.

D. Foschi; P. Cellerino; F. Corsi; T. Taidelli; E. Morandi; A. Rizzi; E. Trabucchi

2002-01-01

176

The Rheology of Blood Flow in a Branched Arterial System.  

PubMed

Blood flow rheology is a complex phenomenon. Presently there is no universally agreed upon model to represent the viscous property of blood. However, under the general classification of non-Newtonian models that simulate blood behavior to different degrees of accuracy, there are many variants. The power law, Casson and Carreau models are popular non-Newtonian models and affect hemodynamics quantities under many conditions. In this study, the finite volume method is used to investigate hemodynamics predictions of each of the models. To implement the finite volume method, the computational fluid dynamics software Fluent 6.1 is used. In this numerical study the different hemorheological models are found to predict different results of hemodynamics variables which are known to impact the genesis of atherosclerosis and formation of thrombosis. The axial velocity magnitude percentage difference of up to 2 % and radial velocity difference up to 90 % is found at different sections of the T-junction geometry. The size of flow recirculation zones and their associated separation and reattachment point's locations differ for each model. The wall shear stress also experiences up to 12 % shift in the main tube. A velocity magnitude distribution of the grid cells shows that the Newtonian model is close dynamically to the Casson model while the power law model resembles the Carreau model. ZUSAMMENFASSUNG: Die Rheologie von Blutströmungen ist ein komplexes Phänomen. Gegenwärtig existiert kein allgemein akzeptiertes Modell, um die viskosen Eigenschaften von Blut wiederzugeben. Jedoch gibt es mehrere Varianten unter der allgemeinen Klassifikation von nicht-Newtonschen Modellen, die das Verhalten von Blut mit unterschiedlicher Genauigkeit simulieren. Die Potenzgesetz-, Casson und Carreau-Modelle sind beliebte nicht-New-tonsche Modelle und beeinflussen die hämodynamischen Eigenschaften in vielen Situationen. In dieser Studie wurde die finite Volumenmethode angewandt, um die hämodynamischen Vorhersagen dieser Modelle zu untersuchen. Um die finite Volumenmethode zu implementieren, wurde die Fluiddynamiksoftware Fluent 6.1 verwendet. In dieser numerischen Studie wurde gefunden, dass die unterschiedlichen hämorheologischen Modelle unterschiedliche Resultate für die hämodynamischen Grössen vorhersagen, von denen bekannt ist, dass sie die Entstehung von Arteriosklerose und die Bildung von Thrombose beeinflussen. Es wurde gefunden, dass die relative Differenz der axialen Geschwindigkeit bis zu 2% und die der radialen Geschwindigkeit bis zu 90% in unterschiedlichen Abschnitten der T-Verbindung beträgt. Die Grösse der Strömungszirkulationszonen und ihrer dazugehörigen Trennungs- und Vereinigungspunkte differieren für jedes Modell. Die Scherspannung an der Wand erfährt ebenfalls eine Verschiebung im Hauptrohr von bis zu 12%. Der Verlauf der Geschwindigkeit auf den Gitterzellen zeigt, dass das Newtonsche Modell mit Bezug auf die Dynamik dem Casson-Modell nahe ist, während das Potenzgesetzmodell dem Carreau-Modell ähnlich ist. R#ENTITYSTARTX000E9;SUM#ENTITYSTARTX000E9;: La rhéologie de l'écoulement sanguin est un phénomène complexe. Présentement, il n'y a pas de consensus universel sur le modèle qui représente la propriété visqueuse du sang. Cependant, parmi la classification générale des modèles non-Newtoniens qui simulent le comportement du sang avec différents degrés de précision, il y a plusieurs différences. Les lois de puissance, les modèles de Casson et Carreau sont des modèles non-Newtoniens populaires et ont un effet sur les quantités hémodynamiques sous plusieurs conditions. Dans cette étude, la méthode de volume fini est utilisée pour explorer les prédictions hémodynamiques de chacun de ces modèles. Pour implémenter la méthode de volume fini, le logiciel de calcul de dynamique des fluides Fluent 6.1 a été utilisé. Dans cette étude numérique, les différents modèles hémorhéologiques tendent à prédire des résultats différents pour les variables hémodynamiques qui sont reconnues comme aya

Shibeshi, Shewaferaw S; Collins, William E

2005-01-01

177

The Rheology of Blood Flow in a Branched Arterial System  

PubMed Central

Blood flow rheology is a complex phenomenon. Presently there is no universally agreed upon model to represent the viscous property of blood. However, under the general classification of non-Newtonian models that simulate blood behavior to different degrees of accuracy, there are many variants. The power law, Casson and Carreau models are popular non-Newtonian models and affect hemodynamics quantities under many conditions. In this study, the finite volume method is used to investigate hemodynamics predictions of each of the models. To implement the finite volume method, the computational fluid dynamics software Fluent 6.1 is used. In this numerical study the different hemorheological models are found to predict different results of hemodynamics variables which are known to impact the genesis of atherosclerosis and formation of thrombosis. The axial velocity magnitude percentage difference of up to 2 % and radial velocity difference up to 90 % is found at different sections of the T-junction geometry. The size of flow recirculation zones and their associated separation and reattachment point's locations differ for each model. The wall shear stress also experiences up to 12 % shift in the main tube. A velocity magnitude distribution of the grid cells shows that the Newtonian model is close dynamically to the Casson model while the power law model resembles the Carreau model. Zusammenfassung Die Rheologie von Blutströmungen ist ein komplexes Phänomen. Gegenwärtig existiert kein allgemein akzeptiertes Modell, um die viskosen Eigenschaften von Blut wiederzugeben. Jedoch gibt es mehrere Varianten unter der allgemeinen Klassifikation von nicht-Newtonschen Modellen, die das Verhalten von Blut mit unterschiedlicher Genauigkeit simulieren. Die Potenzgesetz-, Casson und Carreau-Modelle sind beliebte nicht-New-tonsche Modelle und beeinflussen die hämodynamischen Eigenschaften in vielen Situationen. In dieser Studie wurde die finite Volumenmethode angewandt, um die hämodynamischen Vorhersagen dieser Modelle zu untersuchen. Um die finite Volumenmethode zu implementieren, wurde die Fluiddynamiksoftware Fluent 6.1 verwendet. In dieser numerischen Studie wurde gefunden, dass die unterschiedlichen hämorheologischen Modelle unterschiedliche Resultate für die hämodynamischen Größen vorhersagen, von denen bekannt ist, dass sie die Entstehung von Arteriosklerose und die Bildung von Thrombose beeinflussen. Es wurde gefunden, dass die relative Differenz der axialen Geschwindigkeit bis zu 2% und die der radialen Geschwindigkeit bis zu 90% in unterschiedlichen Abschnitten der T-Verbindung beträgt. Die Größe der Strömungszirkulationszonen und ihrer dazugehörigen Trennungs- und Vereinigungspunkte differieren für jedes Modell. Die Scherspannung an der Wand erfährt ebenfalls eine Verschiebung im Hauptrohr von bis zu 12%. Der Verlauf der Geschwindigkeit auf den Gitterzellen zeigt, dass das Newtonsche Modell mit Bezug auf die Dynamik dem Casson-Modell nahe ist, während das Potenzgesetzmodell dem Carreau-Modell ähnlich ist. Résumé La rhéologie de l'écoulement sanguin est un phénomène complexe. Présentement, il n'y a pas de consensus universel sur le modèle qui représente la propriété visqueuse du sang. Cependant, parmi la classification générale des modèles non-Newtoniens qui simulent le comportement du sang avec différents degrés de précision, il y a plusieurs différences. Les lois de puissance, les modèles de Casson et Carreau sont des modèles non-Newtoniens populaires et ont un effet sur les quantités hémodynamiques sous plusieurs conditions. Dans cette étude, la méthode de volume fini est utilisée pour explorer les prédictions hémodynamiques de chacun de ces modèles. Pour implémenter la méthode de volume fini, le logiciel de calcul de dynamique des fluides Fluent 6.1 a été utilisé. Dans cette &

Shibeshi, Shewaferaw S.; Collins, William E.

2006-01-01

178

Nano-textured superhydrophobic tubes for blood vessel replacement therapy  

Microsoft Academic Search

A materials biocompatibility is vital to its success in vivo. Most conventional materials are concerned with producing a good interface between native cells and the surface of the implant. In contrast, stent materials, artificial veins, and other blood contacting devices rely on little or no interaction with the implant surface. When interactions occur, platelets adhere to the surface and may

Isaac Janson

179

Thermal Reactions of Blood Vessels in Vascular Stroke and Heatstroke  

Microsoft Academic Search

Research on the pathophysiology and treatment of brain damage with special focus on thermal vascular responses is the subject of this minireview. Interruption of cerebral blood supply by vascular obstruction, temporary cardiac arrest or hyperthermia causes a sudden attack of vascular stroke or heatstroke with serious consequences. It may not induce immediate cell death, but can precipitate a complex biochemical

Olav Thulesius

2006-01-01

180

The tissue engineering of blood vessels and the heart  

Microsoft Academic Search

The engineering of biological substitutes and strate- gies for the replacement and\\/or repair of blood ves- sels and the components of the heart represents an important challenge for tissue engineering. In this review, the progress to date and the barriers remain- ing are addressed. Even though the progress has been considerable and there are even some approaches that have entered

Robert M. Nerem; Ann E. Ensley

2004-01-01

181

A method for modulation transfer function determination from blood vessel profiles measured in computed tomography  

NASA Astrophysics Data System (ADS)

The recent CT systems yield high spatial resolution in all directions of volumetric images in clinical routine. The quantitative characterization of the performance of CT systems is important for comparing the effects of different scan and reconstruction parameters, for comparing between different CT systems, and for evaluating the accuracy of size and density measurements of fine details in CT images. This paper presents a method to determine the modulation transfer function (MTF) in the scan plane obtained by CT system from profiles of human anatomical structures such as blood vessel measured by clinical measurement conditions without magnified reconstruction. MTF estimations are performed for cylindrical tube phantoms with three different diameters (1 mm, 2 mm, and 3 mm) injected by solution of contrast material and human blood vessels measured by the clinical measurement conditions. We demonstrate the potential usefulness of the method for estimating the MTF from blood vessel profiles measured in CT systems.

Nakaya, Y.; Kawata, Y.; Niki, N.; Ohmatsu, H.; Moriyama, N.

2012-02-01

182

In vitro fabrication of functional three-dimensional tissues with perfusable blood vessels.  

PubMed

In vitro fabrication of functional vascularized three-dimensional tissues has been a long-standing objective in the field of tissue engineering. Here we report a technique to engineer cardiac tissues with perfusable blood vessels in vitro. Using resected tissue with a connectable artery and vein as a vascular bed, we overlay triple-layer cardiac cell sheets produced from coculture with endothelial cells, and support the tissue construct with media perfused in a bioreactor. We show that endothelial cells connect to capillaries in the vascular bed and form tubular lumens, creating in vitro perfusable blood vessels in the cardiac cell sheets. Thicker engineered tissues can be produced in vitro by overlaying additional triple-layer cell sheets. The vascularized cardiac tissues beat and can be transplanted with blood vessel anastomoses. This technique may create new opportunities for in vitro tissue engineering and has potential therapeutic applications. PMID:23360990

Sekine, Hidekazu; Shimizu, Tatsuya; Sakaguchi, Katsuhisa; Dobashi, Izumi; Wada, Masanori; Yamato, Masayuki; Kobayashi, Eiji; Umezu, Mitsuo; Okano, Teruo

2013-01-01

183

Enhanced sonographic imaging to diagnose lymph node metastasis: importance of blood vessel volume and density.  

PubMed

Lymph node size is an important variable in ultrasound diagnosis of lymph node metastasis. However, the size criterion often leads to oversight of tumor-positive lymph nodes within the range of "normal" size, such that more accurate diagnostic criteria for lymph node metastasis are required. In this study, we show how diagnosis of lymph node metastasis can be improved by evaluating changes in blood vessel volume and density using a novel contrast-enhanced high-frequency ultrasound (CE-HFUS) system with Sonazoid. An MRL/MpJ-lpr/lpr (MRL/lpr) mouse model of lymph node metastasis was used in which lymph nodes are similar in size to humans. Metastasis via lymphatic vessels to proper axillary lymph nodes (proper ALN) was induced by injection of tumor cells into the subiliac lymph nodes. Within 21 days of injection, significant increases in blood vessel volume and density, but no increases in the size of the proper ALNs, were observed. The increase in blood vessel density was confirmed with immunohistochemical analysis and was positively related to tumor cell proliferation as measured using bioluminescence imaging. Together, our results showed that alterations in blood vessel volume and density precede alterations in lymph node size in the early stages of lymph node metastasis. Detection of these changes by ultrasonography may offer new criteria for early diagnosis of lymph node metastasis. PMID:23333937

Li, Li; Mori, Shiro; Kodama, Mizuho; Sakamoto, Maya; Takahashi, Shoki; Kodama, Tetsuya

2013-01-18

184

Automated artery-venous classification of retinal blood vessels based on structural mapping method  

NASA Astrophysics Data System (ADS)

Retinal blood vessels show morphologic modifications in response to various retinopathies. However, the specific responses exhibited by arteries and veins may provide a precise diagnostic information, i.e., a diabetic retinopathy may be detected more accurately with the venous dilatation instead of average vessel dilatation. In order to analyze the vessel type specific morphologic modifications, the classification of a vessel network into arteries and veins is required. We previously described a method for identification and separation of retinal vessel trees; i.e. structural mapping. Therefore, we propose the artery-venous classification based on structural mapping and identification of color properties prominent to the vessel types. The mean and standard deviation of each of green channel intensity and hue channel intensity are analyzed in a region of interest around each centerline pixel of a vessel. Using the vector of color properties extracted from each centerline pixel, it is classified into one of the two clusters (artery and vein), obtained by the fuzzy-C-means clustering. According to the proportion of clustered centerline pixels in a particular vessel, and utilizing the artery-venous crossing property of retinal vessels, each vessel is assigned a label of an artery or a vein. The classification results are compared with the manually annotated ground truth (gold standard). We applied the proposed method to a dataset of 15 retinal color fundus images resulting in an accuracy of 88.28% correctly classified vessel pixels. The automated classification results match well with the gold standard suggesting its potential in artery-venous classification and the respective morphology analysis.

Joshi, Vinayak S.; Garvin, Mona K.; Reinhardt, Joseph M.; Abramoff, Michael D.

2012-02-01

185

Role of tissue factor in embryonic blood vessel development  

Microsoft Academic Search

TISSUE factor, a member of the cytokine-receptor superfamily and high-affinity receptor and cofactor for plasma factor Vll\\/VIIa (ref. 1), is the primary cellular initiator of blood coagulation. It is involved in thrombosis and inflammation associated with sepsis, atherosclerosis and cancer2, and can participate in other cellular processes including intracellular signalling3, metastasis4, tumour-associated angiogenesis5, and embryogenesis6. Here we report that inactivation

Peter Carmeliet; Nigel Mackman; Lieve Moons; Thomas Luther; Pierre Gressens; Lise van Vlaenderen; Hilde Demunck; Michael Kasper; Georg Breier; Philippe Evrard; Martin Müller; Werner Risau; Thomas Edgington; Désiré Collen

1996-01-01

186

Image-based vessel-by-vessel analysis for red blood cell and plasma dynamics with automatic segmentation.  

PubMed

The aim of the present study was to test the hypothesis that vascular tones of cortical surface and parenchymal blood flow can be dissociated depending on the perturbation. To this end, a novel image-based analytical method for quantitatively measuring vessel diameters and flow dynamics was developed. The algorithm relies on the spatiotemporal coherence of the pixel intensity changes induced by the transit of the fluorescent signals measured using confocal laser scanning fluorescent microscopy in the rat cerebral cortex. A cocktail of fluorescently labeled red blood cell (RBC) and plasma agents was administered to simultaneously compare RBC and plasma dynamics in the same vascular networks. The time to fluorescent signal appearance and the width of the fluorescent signal were measured in each segment and compared between sodium nitroprusside-induced global and sensory stimulation-induced local perturbation conditions. We observed that infusion of sodium nitroprusside induced significant vasodilation in the surface artery, particularly in the small arteries (1.8-fold increase). Vasodilation induced by sensory stimulation was observed to depend on vessel size, but significant changes were only detected for the small arteries and veins. Measurements of the time to venous appearance revealed that appearance time was extended by sodium nitroprusside, but shortened during forepaw stimulation, relative to the control condition. Both perturbations provoked the largest changes between the small artery and vein segments, indicating that the changes in the appearance time originate from blood passage through parenchymal microcirculation. These findings support the hypothesis that cortical surface vascular tone and parenchymal blood flow are individually coordinated. PMID:22588048

Kawaguchi, Hiroshi; Masamoto, Kazuto; Ito, Hiroshi; Kanno, Iwao

2012-05-12

187

Acrylic resin injection method for blood vessel investigations.  

PubMed

The injection of acrylic resin into vessels is an excellent method for macroscopically and microscopically observing their three-dimensional features. Conventional methods can be enhanced by removal of the polymerization inhibitor (hydroquinone) without requiring distillation, a consistent viscosity of polymerized resin, and a constant injection pressure and speed. As microvascular corrosion cast specimens are influenced by viscosity, pressure, and speed changes, injection into different specimens yields varying results. We devised a method to reduce those problems. Sodium hydroxide was used to remove hydroquinone from commercial methylmethacrylate. The solid polymer and the liquid monomer were mixed using a 1 : 9 ratio (low-viscosity acrylic resin, 9.07 ± 0.52 mPa•s) or a 3:7 ratio (high-viscosity resin, 1036.33 ± 144.02 mPa•s). To polymerize the acrylic resin for injection, a polymerization promoter (1.0% benzoyl peroxide) was mixed with a polymerization initiator (0.5%, N, N-dimethylaniline). The acrylic resins were injected using a precise syringe pump, with a 5-mL/min injection speed and 11.17 ± 1.60 mPa injection pressure (low-viscosity resin) and a 1-mL/min injection speed and 58.50 ± 5.75 mPa injection pressure (high-viscosity resin). Using the aforementioned conditions, scanning electron microscopy indicated that sufficient resin could be injected into the capillaries of the microvascular corrosion cast specimens. PMID:24107720

Suwa, Fumihiko; Uemura, Mamoru; Takemura, Akimichi; Toda, Isumi; Fang, Yi-Ru; Xu, Yuan Jin; Zhang, Zhi Yuan

2013-01-01

188

Fluid-structure interaction analysis on the effects of vessel material properties on blood flow characteristics in stenosed arteries under axial rotation  

Microsoft Academic Search

We conducted blood flow analysis, using the Fluid-Structure Interaction (FSI) method, to examine how changes in the material properties of blood vessels affect blood flow characteristics, using the carotid artery as the model vessel. The geometry of the blood vessel included 50% stenosis at the center, and blood was modeled as a non-Newtonian fluid. In order to investigate the effects

Seong Wook Cho; Seung Wook Kim; Moon Hyun Sung; Kyoung Chul Ro; Hong Sun Ryou

2011-01-01

189

The blood circulation inside the spleen. I. The arterial blood vessels general distribution in the rat spleen.  

PubMed

As an attempt to investigate the different pathways followed by the blood into the spleen and to analyse their functional significance, a technique was used mainly based on the intraarterial perfusion of a Prussian blue "solution" added of some chemical mediators and vasoactive substances. Such technique provides results which may be analysed taking into account the effect of the anaesthetic used, that may influence the findings. From the anaesthetic used, the sulfuric ether and the barbital sodium produce vasoconstriction of the white pulp blood vessels, whereas the chlorpromazine-promethazine doesn't have this effect, and so the Prussian blue appears inside these vessels. The vasodilator drugs, such as succinonitrile and papaverine hydrochloride, show a general vasodilator effect on the splenic arterial system. Teh arterial vessels of the white and the red pulp, including those placed at the subcapsular areas, become enlarged; into the white pulp, either the central or the peripheral blood vessel plexus of the lymphatic follicle becomes evident. The latter readily constitutes the perifollicular and the pericolumnar plexus. The blood vessels of this plexus become permeable to the Prussian blue "solution" by the heparin sodium effect, and so the dye particles enter the marginal zone and the splenic sinuses. In addition, from the white pulp arteries arise 2 types of anastomotic arterioles which appear enlarged after succinonitrile treatment: The short anastomotic arterioles that crosses the marginal zone entering the red pulp near the white pulp; the long anastomotic arterioles which enter the red pulp and after a long course end up into or around a collector sinus. The addition of histamine dihydrochloride to the perfusion solutions shows a slight vasodilator effect mainly on the subcapsular penicillar arterioles, including the helicine arterioles. The adrenergic stimulation of the splenic blood vessels induces a generalized arterial constriction, except of the anastomotic arterioles, that becomes open; in such way, the blood pathway follows the course of the anastomotic arterioles and the collector arterioles also become constricted. The adrenergic vasoconstrictor effect is inhibited by the phenoxy-benzamine hydrochloride. The addition of acetylcholine chloride, in the dosage, used, induces a generalized arterial vessel constriction, mainly of the perifollicular plexus. This effect is inhibited by atropine sulfate which, on the other hand, produces evident enlargement of the perifollicular and pericolumnar arterial plexus. PMID:2756746

Hadler, W A; Silveira, S R

1989-01-01

190

A Microstructurally Motivated Model of the Mechanical Behavior of Tissue Engineered Blood Vessels  

PubMed Central

Mechanical models have potential to guide the development and use of engineered blood vessels as well as other engineered tissues. This paper presents a microstructurally motivated, pseudoelastic, mechanical model of the biaxial mechanics of engineered vessels in the physiologic pressure range. The model incorporates experimentally measured densities and alignments of engineered collagen. Specifically, these microstructural and associated mechanical inputs were measured directly from engineered blood vessels that were cultured over periods of 5–7.5 weeks. To the best of our knowledge, this is the first successful application of either a phenomenological or a microstructurally motivated mechanical model to engineered vascular tissues. Model development revealed the need to use novel theoretical configurations to describe the strain history of engineered vessels. The constitutive equations developed herein suggested that collagen remodeled between 5 and 7.5 weeks during a 7.5-week culture period. This remodeling led to strain energies for collagen that differed with alignment, which likely resulted from undulations that varied with alignment. Finally, biaxial data emphasized that axial extensions increase stresses in engineered vessels in the physiologic pressure range, thereby providing a guideline for surgical use: engineered vessels should be implanted at appropriate axial extension to minimize adverse stress responses.

Dahl, Shannon L. M.; Vaughn, Megann E.; Hu, Jin-Jia; Driessen, Niels J. B.; Baaijens, Frank P. T.; Humphrey, Jay D.; Niklason, Laura E.

2008-01-01

191

Versatility of lateral cutaneous branches of intercostal vessels and nerves: Anatomical study and clinical application.  

PubMed

The use of the intercostal artery perforator (ICAP) flap has recently become popular in reconstructions of the breast, upper arm and trunk. Lateral cutaneous branches (LCBs) are a group of the ICAPs that penetrate the fascia near the middle axillary line. However, reports on its precise anatomy and clinical applications are quite limited. We performed an anatomical study of LCBs using cadavers. Based on the findings, we developed novel clinical application methods as follows: (1) sensate superficial circumflex iliac perforator (SCIP) flap, (2) supercharged SCIP flap, (3) ICAP-based propeller flap (IBPF) and (4) free ICAP flap based on LCB. LCBs have the following advantages: (1) Long pedicles can be obtained in the supine position without risk of pneumothorax. (2) The neurovascular bundle is consistently available, allowing elevation of sensate flaps. (3) Donor-site morbidity is low. Therefore, we believe that LCBs offer a versatile option in reconstructive surgery. PMID:23896163

Iida, Takuya; Narushima, Mitsunaga; Yoshimatsu, Hidehiko; Mihara, Makoto; Kikuchi, Kazuki; Hara, Hisako; Yamamoto, Takumi; Araki, Jun; Koshima, Isao

2013-07-26

192

Occlusion of Small Vessels by Malaria-Infected Red Blood Cells  

NASA Astrophysics Data System (ADS)

We use dissipative particle dynamics (DPD) method to study malaria-infected red blood cells (i-RBC). We have developed a multi-scale model to describe both static and dynamic properties of RBCs. With this model, we study the adhesive interaction between RBCs as well as the interaction between the Plasmodium falciparum (Pf)-parasitized cells and a vessel wall coated with purified ICAM-1. In this talk, we will discuss the effect of the Pf-parasitized malaria cell on the flow resistance of the blood flow at different parasetimia levels. The blood flow in malaria disease shows high flow resistance as compared with the healthy case due to both the stiffening of the i-RBCs (up to ten times) as well as the adhesion dynamics. For certain sizes of of small vessels, the malaria-infected cells can even lead to occlusion of the blood flow, in agreement with recent experiments.

Lei, Huan; Fedosov, Dmitry; Caswell, Bruce; Karniadakis, George

2010-11-01

193

PDGF signaling is required for epicardial function and blood vessel formation in regenerating zebrafish hearts.  

PubMed

A zebrafish heart can fully regenerate after amputation of up to 20% of its ventricle. During this process, newly formed coronary blood vessels revascularize the regenerating tissue. The formation of coronary blood vessels during zebrafish heart regeneration likely recapitulates embryonic coronary vessel development, which involves the activation and proliferation of the epicardium, followed by an epithelial-to-mesenchymal transition. The molecular and cellular mechanisms underlying these processes are not well understood. We examined the role of PDGF signaling in explant-derived primary cultured epicardial cells in vitro and in regenerating zebrafish hearts in vivo. We observed that mural and mesenchymal cell markers, including pdgfr?, are up-regulated in the regenerating hearts. Using a primary culture of epicardial cells derived from heart explants, we found that PDGF signaling is essential for epicardial cell proliferation. PDGF also induces stress fibers and loss of cell-cell contacts of epicardial cells in explant culture. This effect is mediated by Rho-associated protein kinase. Inhibition of PDGF signaling in vivo impairs epicardial cell proliferation, expression of mesenchymal and mural cell markers, and coronary blood vessel formation. Our data suggest that PDGF signaling plays important roles in epicardial function and coronary vessel formation during heart regeneration in zebrafish. PMID:20858732

Kim, Jieun; Wu, Qiong; Zhang, Yolanda; Wiens, Katie M; Huang, Ying; Rubin, Nicole; Shimada, Hiroyuki; Handin, Robert I; Chao, Michael Y; Tuan, Tai-Lan; Starnes, Vaughn A; Lien, Ching-Ling

2010-09-21

194

PDGF signaling is required for epicardial function and blood vessel formation in regenerating zebrafish hearts  

PubMed Central

A zebrafish heart can fully regenerate after amputation of up to 20% of its ventricle. During this process, newly formed coronary blood vessels revascularize the regenerating tissue. The formation of coronary blood vessels during zebrafish heart regeneration likely recapitulates embryonic coronary vessel development, which involves the activation and proliferation of the epicardium, followed by an epithelial-to-mesenchymal transition. The molecular and cellular mechanisms underlying these processes are not well understood. We examined the role of PDGF signaling in explant-derived primary cultured epicardial cells in vitro and in regenerating zebrafish hearts in vivo. We observed that mural and mesenchymal cell markers, including pdgfr?, are up-regulated in the regenerating hearts. Using a primary culture of epicardial cells derived from heart explants, we found that PDGF signaling is essential for epicardial cell proliferation. PDGF also induces stress fibers and loss of cell-cell contacts of epicardial cells in explant culture. This effect is mediated by Rho-associated protein kinase. Inhibition of PDGF signaling in vivo impairs epicardial cell proliferation, expression of mesenchymal and mural cell markers, and coronary blood vessel formation. Our data suggest that PDGF signaling plays important roles in epicardial function and coronary vessel formation during heart regeneration in zebrafish.

Kim, Jieun; Wu, Qiong; Zhang, Yolanda; Wiens, Katie M.; Huang, Ying; Rubin, Nicole; Shimada, Hiroyuki; Handin, Robert I.; Chao, Michael Y.; Tuan, Tai-Lan; Starnes, Vaughn A.; Lien, Ching-Ling

2010-01-01

195

Polarized Monte Carlo simulation of blood vessel structure in colon tissue  

NASA Astrophysics Data System (ADS)

A modified polarized Monte Carlo code is developed that allows heterogeneous structure to be modeled. The code is validated with existent polarized Monte Carlo code. Heterogeneous structure simulating colon tissue is simulated to understand the difference between simulations of homogeneous vs heterogeneous tissue structure. Reflectance measurements from simulations containing increased blood vessel size and increased blood volume fraction, both markers for potential cancerous tissue, are studied in order to better interpret reflectance measurement from diagnostic probes.

Yip, Wendy; Gomes, Andrew; Backman, Vadim; Sahakian, Alan

2012-02-01

196

A New Adaptive Probabilistic Model of Blood Vessels for Segmenting MRA Images  

Microsoft Academic Search

\\u000a A new physically justified adaptive probabilistic model of blood vessels on magnetic resonance angiography (MRA) images is\\u000a proposed. The model accounts for both laminar (for normal subjects) and turbulent blood flow (in abnormal cases like anemia\\u000a or stenosis) and results in a fast algorithm for extracting a 3D cerebrovascular system from the MRA data. Experiments with\\u000a synthetic and 50 real

Ayman El-baz; Aly A. Farag; Georgy L. Gimel'farb; Mohamed Abou El-ghar; Tarek Eldiasty

2006-01-01

197

Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels  

PubMed Central

Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-?1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors —inexpensive drugs with decades of safe use — could be rapidly repurposed as cancer therapeutics.

Chauhan, Vikash P.; Martin, John D.; Liu, Hao; Lacorre, Delphine A.; Jain, Saloni R.; Kozin, Sergey V.; Stylianopoulos, Triantafyllos; Mousa, Ahmed S.; Han, Xiaoxing; Adstamongkonkul, Pichet; Popovic, Zoran; Huang, Peigen; Bawendi, Moungi G.; Boucher, Yves; Jain, Rakesh K.

2013-01-01

198

In vivo results using photothermal tomography for imaging cutaneous blood vessels  

NASA Astrophysics Data System (ADS)

Previous studies suggest that optimal port wine stain (PWS) laser treatment parameters require knowledge of skin characteristics such as blood vessel size, depth, and distribution. Effective and rapid imaging modalities are not widely available. In the present study, photothermal tomography (PTT) images of an in vivo hamster window model and human PWS skin were obtained and analyzed. Subtherapeutic laser light pulses at 585 and 600 nm were applied to skin surface and image sequences acquired with an infrared camera. A nonnegatively constrained conjugate gradient algorithm was used to reconstruct a PTT image of the initial temperature distribution immediately following pulsed laser irradiation. Vessel dimensions determined from PTT images of hamster window model skin compared well with those measured directly using video microscopy. PTT images of human PWS skin contained vessels with estimated diameters of 200-250 ?m over a 250-320 ?m depth range. Use of dual wavelength excitation (DWE) analysis allowed for imaging of shallow vessels.

Choi, Bernard; Majaron, Boris; Vargas, Gracie; Jung, Byungjo; Stumpp, Oliver F.; Kang, Nicole M.; Kelly, Kristen M.; Welch, Ashley J.; Nelson, J. Stuart

2003-07-01

199

Locating Blood Vessels in Retinal Images by Piece-wise Threshold Probing of a Matched Filter Response  

Microsoft Academic Search

We describe an automated method to locate and outline blood vessels in images of the ocular fundus. Such a tool should prove useful to eye care specialists for purposes of patient screening, treatment evaluation, and clinical study. Our method differs from previously known methods in that it uses local and global vessel features cooperatively to segment the vessel network. We

Adam Hoover; Valentina Kouznetsova; Michael H. Goldbaum

2000-01-01

200

Mechanism of IL12 mediated alterations in tumour blood vessel morphology: analysis using whole-tissue mounts  

Microsoft Academic Search

New blood vessel formation within tumours is a critical feature for tumour growth. A major limitation in understanding this complex process has been the inability to visualise and analyse vessel formation. Here, we report on the development of a whole-tissue mount technique that allows visualisation of vessel structure. Mice expressing green fluorescent protein (GFP) made it possible to easily see

S A Gerber; J P Moran; J G Frelinger; J A Frelinger; B M Fenton; E M Lord; EM Lord

2003-01-01

201

Quantitative analysis of the density and pattern of adrenergic innervation of blood vessels  

Microsoft Academic Search

Automated quantitative image analysis (QIAF) was used to measure and compare the adrenergic nerve plexuses of 4 blood vessels from the guinea pig, demonstrated by glyoxylic acid fluorescence (GAF). The results showed considerable quantitative variation of plexus density, size of bundles, and numbers of varicosities. A range of alternative procedural and anatomical sources of variability were investigated and assessed. The

T. Cowen; G. Burnstock

1980-01-01

202

Statistical-Based Approach for Extracting 3D Blood Vessels from TOF-MyRA Data  

Microsoft Academic Search

In this paper we present an automatic statistical intensity based- approach for extracting the 3D cerebrovascular system from time-of-flight (TOF) magnetic resonance angiography (MRA) data. The voxels of the dataset are classified as either background tissues, which are modeled by a finite mixture of one Rayleigh and two normal distributions, or blood vessels, which are modeled by one normal distribution.

M. Sabry Hassouna; Aly A. Farag; Stephen G. Hushek; Thomas Moriarty

2003-01-01

203

A Blood Vessel Model Constructed from Collagen and Cultured Vascular Cells  

Microsoft Academic Search

A model of a blood vessel was constructed in vitro. Its multilayered structure resembled that of an artery and it withstood physiological pressures. Electron microscopy showed that the endothelial cells lining the lumen and the smooth muscle cells in the wall were healthy and well differentiated. The lining of endothelial cells functioned physically, as a permeability barrier, and biosynthetically, producing

Crispin B. Weinberg; Eugene Bell

1986-01-01

204

Heterogeneity of Angiogenesis and Blood Vessel Maturation in Human Tumors: Implications for Antiangiogenic Tumor Therapies1  

Microsoft Academic Search

Microvessel density (MVD) counting techniques have been widely used to assess the vasculature in tumors. MVD counts assess the presence of blood vessels but do not give an indication of the degree of angiogenesis and the functional status of the tumor neovasculature. To analyze angiogenesis and the functional status of the tumor vascular bed, we have quantitated endo- thelial cell

Anne Eberhard; Sebastian Kahlert; Valentin Goede; Bernhard Hemmerlein; Karl H. Plate; Hellmut G. Augustin

2000-01-01

205

Low level arsenic promotes progressive inflammatory angiogenesis and liver blood vessel remodeling in mice  

Microsoft Academic Search

The vascular effects of arsenic in drinking water are global health concerns contributing to human disease worldwide. Arsenic targets the endothelial cells lining blood vessels, and endothelial cell activation or dysfunction may underlie the pathogenesis of both arsenic-induced vascular diseases and arsenic-enhanced tumorigenesis. The purpose of the current studies was to demonstrate that exposing mice to drinking water containing environmentally

Adam C. Straub; Donna B. Stolz; Harina Vin; Mark A. Ross; Nicole V. Soucy; Linda R. Klei; Aaron Barchowsky

2007-01-01

206

Implantation of blood vessels into a free bone graft to promote its revascularization  

Microsoft Academic Search

Experiments on rats were used to study the revascularization of a free autogenous bone graft following implantation of blood vessels. The free grafts consisted of tail vertebrae, with a vascular bundle or an artery introduced into the marrow cavity. It was found that proliferation of capillaries promoting revascularization of the graft originated from the adventitia of the implanted artery. It

J. Valka; J. Šmahel; V. E. Meyer

1984-01-01

207

[Length and surface density of the resorption villi's blood vessels in smokers placentas].  

PubMed

This study was conducted with intention to reveal the quantitative values of feto-maternal nutrition exchange in smokers placentas, considering the great importance of harmful influence of smoking in pregnancy. The study was done on 90 human placentas. We have divided them into three groups: 30 placentas of moderate smokers, 30 placentas of heavy smokers and control group (non-smokers). Stereologic analysis was done with multipurpose test system M42. Pregnant smokers (both moderate and heavy) had significantly lower length density of the blood vessels compared to the control group. Significantly higher surface density of the blood vessels was found in the pregnant heavy smokers. The least absolute length density of the resorption villi's blood vessels was in the pregnant heavy smokers and it was significantly lower compared to pregnant moderate smokers and control group. In the group of the pregnant heavy smokers there was statistically higher average absolute surface of the blood vessels. The intensity of smoking effects the structural changes of the placenta. Intensity of smoking during pregnancy had a great impact on the proportion of the morphologic changes of the placentas. It leads to hypoxia, which in turn may be the cause of fetal growth and developmental retardation. PMID:19145800

Zigi?, Zlata; Bogdanovi?, Gordana; Rami?, Suada

2008-01-01

208

HIFU procedures at moderate intensities—effect of large blood vessels  

Microsoft Academic Search

A three-dimensional computational model is presented for studying the efficacy of high-intensity focused ultrasound (HIFU) procedures targeted near large blood vessels. The analysis applies to procedures performed at intensities below the threshold for cavitation, boiling and highly nonlinear propagation, but high enough to increase tissue temperature a few degrees per second. The model is based upon the linearized KZK equation

P Hariharan; M R Myers; R K Banerjee

2007-01-01

209

Factors associated with access blood flow in native vessel arteriovenous fistulae  

Microsoft Academic Search

Background. Access blood flow (Qa) identifies stenosis in patients with native vessel AV fistulae (AVF), but data on factors that are associated with Qa in normally functioning accesses are sparse. Such factors could be used in conjunction with Qa to improve the diagnostic performance of screening. We examined the relation- ship between Qa and certain clinical characteristics in a large

Marcello Tonelli; David J. Hirsch; Christopher T. Chan; Joanne Marryatt; Paula Mossop; Colleen Wile; Kailash Jindal

2004-01-01

210

Measurements of Dynamic Viscoelasticity of Poly (vinyl alcohol) Hydrogel for the Development of Blood Vessel Biomodeling  

NASA Astrophysics Data System (ADS)

In vitro blood vessel biomodeling with realistic mechanical properties and geometrical structures is helpful for training in surgical procedures, especial those used in endovascular treatment. Poly (vinyl alcohol) hydrogel (PVA-H), which is made of Poly (vinyl alcohol) (PVA) and water, may be useful as a material for blood vessel biomodeling due to its low surface friction resistance and good transparency. In order to simulate the mechanical properties of blood vessels, measurements of mechanical properties of PVA-H were carried out with a dynamic mechanical analyzer, and the storage modulus (G’) and loss modulus (G”) of PVA-H were obtained. PVA-Hs were prepared by the low-temperature crystallization method. They were made of PVA with various concentrations (C) and degrees of polymerization (DP), and made by blending two kinds of PVA having different DP or saponification values (SV). The G’ and G” of PVA-H increased, as the C or DP of PVA increased, or as the proportion of PVA with higher DP or SV increased. These results indicate that it is possible to obtain PVA-H with desirable dynamic viscoelasticity. Furthermore, it is suggested that PVA-H is stable in the temperature range of 0°C to 40°C, indicating that biomodeling made of PVA-H should be available at 37°C, the physiological temperature. The dynamic viscoelasticity of PVA-H obtained was similar to that of the dog blood vessel measured in previous reports. In conclusion, PVA-H is suggested to be useful as a material of blood vessel biomodeling.

Kosukegawa, Hiroyuki; Mamada, Keisuke; Kuroki, Kanju; Liu, Lei; Inoue, Kosuke; Hayase, Toshiyuki; Ohta, Makoto

211

Evolution of bubbles from gas micronuclei formed on the luminal aspect of ovine large blood vessels.  

PubMed

It has been shown that tiny gas nanobubbles form spontaneously on a smooth hydrophobic surface submerged in water. These nanobubbles were shown to be the source of gas micronuclei from which bubbles evolved during decompression of silicon wafers. We suggest that the hydrophobic inner surface of blood vessels may be a site of nanobubble production. Sections from the right and left atria, pulmonary artery and vein, aorta, and superior vena cava of sheep (n=6) were gently stretched on microscope slides and exposed to 1013 kPa for 18 h. Hydrophobicity was checked in the six blood vessels by advancing contact angle with a drop of saline of 71±19°, with a maximum of about 110±7° (mean±SD). Tiny bubbles ~30 ?m in diameter rose vertically from the blood vessels and grew on the surface of the saline, where they were photographed. All of the blood vessels produced bubbles over a period of 80 min. The number of bubbles produced from a square cm was: in the aorta, 20.5; left atrium, 27.3; pulmonary artery, 17.9; pulmonary vein, 24.3; right atrium, 29.5; superior vena cava, 36.4. More than half of the bubbles were present for less than 2 min, but some remained on the saline-air interface for as long as 18 min. Nucleation was evident in both the venous (superior vena cava, pulmonary artery, right atrium) and arterial (aorta, pulmonary vein, left atrium) blood vessels. This newly suggested mechanism of nucleation may be the main mechanism underlying bubble formation on decompression. PMID:23624230

Arieli, R; Marmur, A

2013-04-25

212

Mathematical Analysis of Landis-Type Experiments on the Transport of Fluid Across the Walls of Capillary Blood Vessels.  

National Technical Information Service (NTIS)

A simplified model of the fluid transport phenomena across the wall of a capillary blood vessel is studied. An analytical method is presented to study the significance of Starling's law in the motion of the plasma in an occluded capillary blood vessel. In...

H. S. Lew Y. C. Fung

1968-01-01

213

[Anti-aggregant activity of the blood vessel wall and its regulation by GABAergic agents in hypokinesia].  

PubMed

Restricted motor activity on the background of platelet hyperaggregation in the whole blood and plasma leads to inhibition of the antiaggregant activity of the blood vessel wall, thus creating prerequisites for the development of thromboembolic disturbances. Under these conditions, GABA and piracetam produce a pronounced protective action with respect to the platelet-vessel wall interactions. PMID:11109525

Edigarova, L V; Akopian, V P

214

Is the clustering of ?-amyloid (A?) deposits in the frontal cortex of Alzheimer patients determined by blood vessels?  

Microsoft Academic Search

The clustering pattern of diffuse, primitive and classic ?-amyloid (A?) deposits was studied in the upper laminae of the frontal cortex of 9 patients with sporadic Alzheimer's disease (AD). A? stained tissue was counterstained with collagen type IV antiserum to determine whether the clusters of A? deposits were related to blood vessels. In all patients, A? deposits and blood vessels

R. A. Armstrong

1995-01-01

215

Increased angiogenesis and blood vessel maturation in acellular collagen–heparin scaffolds containing both FGF2 and VEGF  

Microsoft Academic Search

An important issue in tissue engineering is the vascularisation of the implanted construct, which often takes several weeks. In vivo, the growth factors VEGF and FGF2 show a combined effect on both angiogenesis and maturation of blood vessels. Therefore, we hypothesise that the addition of these growth factors to an acellular construct increases blood vessel formation and maturation. To systematically

Suzan T. M. Nillesen; Paul J. Geutjes; Ronnie Wismans; Joost Schalkwijk; Willeke F. Daamen; Toin H. van Kuppevelt

2007-01-01

216

Finite-sized gas bubble motion in a blood vessel: Non-Newtonian effects  

NASA Astrophysics Data System (ADS)

We have numerically investigated the axisymmetric motion of a finite-sized nearly occluding air bubble through a shear-thinning Casson fluid flowing in blood vessels of circular cross section. The numerical solution entails solving a two-layer fluid model—a cell-free layer and a non-Newtonian core together with the gas bubble. This problem is of interest to the field of rheology and for gas embolism studies in health sciences. The numerical method is based on a modified front-tracking method. The viscosity expression in the Casson model for blood (bulk fluid) includes the hematocrit [the volume fraction of red blood cells (RBCs)] as an explicit parameter. Three different flow Reynolds numbers, Reapp=?lUmaxd/?app , in the neighborhood of 0.2, 2, and 200 are investigated. Here, ?l is the density of blood, Umax is the centerline velocity of the inlet Casson profile, d is the diameter of the vessel, and ?app is the apparent viscosity of whole blood. Three different hematocrits have also been considered: 0.45, 0.4, and 0.335. The vessel sizes considered correspond to small arteries, and small and large arterioles in normal humans. The degree of bubble occlusion is characterized by the ratio of bubble to vessel radius (aspect ratio), ? , in the range 0.9???1.05 . For arteriolar flow, where relevant, the Fahraeus-Lindqvist effects are taken into account. Both horizontal and vertical vessel geometries have been investigated. Many significant insights are revealed by our study: (i) bubble motion causes large temporal and spatial gradients of shear stress at the “endothelial cell” (EC) surface lining the blood vessel wall as the bubble approaches the cell, moves over it, and passes it by; (ii) rapid reversals occur in the sign of the shear stress (+ ? - ? +) imparted to the cell surface during bubble motion; (iii) large shear stress gradients together with sign reversals are ascribable to the development of a recirculation vortex at the rear of the bubble; (iv) computed magnitudes of shear stress gradients coupled with their sign reversals may correspond to levels that cause injury to the cell by membrane disruption through impulsive compression and stretching; and (v) for the vessel sizes and flow rates investigated, gravitational effects are negligible.

Mukundakrishnan, Karthik; Ayyaswamy, Portonovo S.; Eckmann, David M.

2008-09-01

217

VE-cadherin is not required for the formation of nascent blood vessels but acts to prevent their disassembly  

Microsoft Academic Search

We investigated the role of vascular endo- thelial (VE)-cadherin in blood vessel mor- phogenesis and established a temporal correlation linking the failure in vessel morphogenesis in VE-cadherin null em- bryos to a specific step in vasculogen- esis. We showed that the sequence in which blood vessels failed followed the order in which they had formed (ie, those forming first—yolk sac,

Christopher V. Crosby; Paul A. Fleming; W. Scott Argraves; Monica Corada; Lucia Zanetta; Elisabetta Dejana; Christopher J. Drake

2005-01-01

218

Selective Thrombosis of Tumor Blood Vessels in Mammary Adenocarcinoma Implants in Rats  

PubMed Central

Adenocarcinomas in rats and humans frequently contain perivascular, degranulating mast cells that release heparin. Protamine is a low-molecular weight, cationic polypeptide that binds avidly to heparin and neutralizes its anticoagulant properties. We hypothesized that mast-cell heparin functions as a localized anticoagulant that modulates hemostasis and blood perfusion in tumors. Consequently, systemically administered protamine should be able to neutralize the endogenous heparin within tumors, thereby inducing selective thrombosis of blood vessels within tumors. Here we demonstrate with magnetic resonance imaging (MRI) that an intravenous dose of protamine labeled with gadolinium accumulated within the parenchyma of subcutaneous implants of a mammary adenocarcinoma in Fischer 344 rats. Moreover, we show with dynamic contrast enhanced MRI that sequential intravenous doses of protamine in 12 tumor-bearing rats resulted in significantly decreased signal enhancement kinetics (blood perfusion) of the tumor. This functional impairment of MRI signal enhancement was accompanied by histological evidence of thrombosis in the blood vessels within the tumor. There was no histological evidence of thrombosis within normal liver, kidney, lung, spleen, or adjacent muscle of tumor-bearing animals that received protamine treatment or in the tumors of animals that had not been pretreated with protamine. On the basis of these results, we conclude that protamine accumulates within adenocarcinoma implants and induces selective thrombosis of blood vessels within the tumor, probably by neutralizing the endogenous heparin within tumors.

Samoszuk, Michael K.; Su, Min-Ying; Najafi, Ahmad; Nalcioglu, Orhan

2001-01-01

219

Automated image analysis for measurements of morphological reactions of blood vessels of the microvascular system.  

PubMed

Using a modification of the Mg-ATPase reaction, the arterial blood vessels of the microcirculatory bed of the rat including the smallest precapillary vessels are visualized in a grey-level difference against their environment which permits to utilize the automatic image analyser QUANTIMET 720 and the programmable desk-top calculator HEWLETT-PACKARD 9100B. The article describes the method for preparing the sections, the measuring procedure, and the statistical verification of the results by means of the computer assisted two-way analysis of variance as well as studies demonstrating the reliability of the method. It is concluded that the procedure at heart, skeletal muscle and pancreas specimens of the rat demonstrates reliably and effectively changes of the number of vessels and the projected whole vessel wall area as well as differences of enzyme activities. Thus it is possible to detect structural wall reactions and enzyme histochemical changes of arterial blood vessels of the microvasculatory bed including its smallest precapillaries which have been practically inaccessible to histomorphometrical investigations in the past. PMID:157283

Herrmann, H J; Mühlig, P; Kühne, C; Läuter, J

1979-01-01

220

Involvement of non-vascular stem cells in blood vessel formation.  

PubMed

Blood vessels clearly act as conduits for blood flow, but recently the concept that they are also involved in organ maintenance, especially by providing a niche for organ-specific stem cells, has begun to emerge. Moreover, several lines of evidence suggest that hematopoietic stem cells can differentiate directly into cells composing blood vessels. Recently, cancer stem cells (CSCs) have also been assigned these roles in the cancer microenvironment. Although anti-angiogenic drugs have been developed and are utilized in the clinic for their anti-tumor activity, their suppressive effects on tumor growth have been disappointing. This may be caused by transferring drug resistance from CSCs to endothelial cells. It has been suggested that CSCs localize in the peri-vascular niche. Therefore, it is extremely important to know how the vascular niche maintains CSCs, as such knowledge may enable us to develop promising new approaches to cancer treatment. PMID:22307804

Takakura, Nobuyuki

2012-02-04

221

Diabetic retinopathy: a quadtree based blood vessel detection algorithm using RGB components in fundus images.  

PubMed

Blood vessel detection in retinal images is a fundamental step for feature extraction and interpretation of image content. This paper proposes a novel computational paradigm for detection of blood vessels in fundus images based on RGB components and quadtree decomposition. The proposed algorithm employs median filtering, quadtree decomposition, post filtration of detected edges, and morphological reconstruction on retinal images. The application of preprocessing algorithm helps in enhancing the image to make it better fit for the subsequent analysis and it is a vital phase before decomposing the image. Quadtree decomposition provides information on the different types of blocks and intensities of the pixels within the blocks. The post filtration and morphological reconstruction assist in filling the edges of the blood vessels and removing the false alarms and unwanted objects from the background, while restoring the original shape of the connected vessels. The proposed method which makes use of the three color components (RGB) is tested on various images of publicly available database. The results are compared with those obtained by other known methods as well as with the results obtained by using the proposed method with the green color component only. It is shown that the proposed method can yield true positive fraction values as high as 0.77, which are comparable to or somewhat higher than the results obtained by other known methods. It is also shown that the effect of noise can be reduced if the proposed method is implemented using only the green color component. PMID:18461818

Reza, Ahmed Wasif; Eswaran, C; Hati, Subhas

2008-04-01

222

Method to obtain the high contrast images of blood vessel for oxygen saturation calculation  

NASA Astrophysics Data System (ADS)

The skin illuminated of two lights at different wavelength can be applied to detect the oxygen saturation of human blood. Due to the absorption coefficient of oxy- (HbO2) and deoxy- (Hb) hemoglobin are different at the wavelength 660 nm and 890 nm, the transmitted and reflected light within the skin can be used to compute the oxygen saturation image of skin. However, the intensities of skin images illuminated by a 20 mW NIR-LED are too low to determine the position of blood vessel when acquired by the color CCD camera. In order to improve the disadvantages, a mono camera was used and the irradiated distance and angle between LED light and test hand were adjusted to acquire the higher resolution and contrast blood vessel images for the oxygen saturation calculation. In the experiment, we developed the suitable angle to irradiate NIR light is at 75 degrees because the reflected and scattered effect could be generated significantly from both vertical and horizontal direction. In addition, the best contrast vessel images can be obtained when the shutter time is set at 44.030 ms and the irradiated distance was at the range 140-160 mm due to the intensity ratio between tissue and vessel region is the highest and the intensities of image would not be saturated or become too low when these two parameters were adjusted slightly. In future, the proposed parameters and results can be applied to the oxygen saturation measurement in the clinical diagnosis.

Tsai, Hsin-Yi; Chen, Yi-Ju; Chang, Han-Chao; Huang, Kuo-Cheng

2013-06-01

223

A comparison of blood vessel features and local binary patterns for colorectal polyp classification  

NASA Astrophysics Data System (ADS)

Colorectal cancer is the third leading cause of cancer deaths in the United States of America for both women and men. By means of early detection, the five year survival rate can be up to 90%. Polyps can to be grouped into three different classes: hyperplastic, adenomatous, and carcinomatous polyps. Hyperplastic polyps are benign and are not likely to develop into cancer. Adenomas, on the other hand, are known to grow into cancer (adenoma-carcinoma sequence). Carcinomas are fully developed cancers and can be easily distinguished from adenomas and hyperplastic polyps. A recent narrow band imaging (NBI) study by Tischendorf et al. has shown that hyperplastic polyps and adenomas can be discriminated by their blood vessel structure. We designed a computer-aided system for the differentiation between hyperplastic and adenomatous polyps. Our development aim is to provide the medical practitioner with an additional objective interpretation of the available image data as well as a confidence measure for the classification. We propose classification features calculated on the basis of the extracted blood vessel structure. We use the combined length of the detected blood vessels, the average perimeter of the vessels and their average gray level value. We achieve a successful classification rate of more than 90% on 102 polyps from our polyp data base. The classification results based on these features are compared to the results of Local Binary Patterns (LBP). The results indicate that the implemented features are superior to LBP.

Gross, Sebastian; Stehle, Thomas; Behrens, Alexander; Auer, Roland; Aach, Til; Winograd, Ron; Trautwein, Christian; Tischendorf, Jens

2009-02-01

224

Effects of Mechanical Stretch on Collagen and Cross-Linking in Engineered Blood Vessels  

PubMed Central

It has been shown that mechanical stimulation affects the physical properties of multiple types of engineered tissues. However, the optimum regimen for applying cyclic radial stretch to engineered arteries is not well understood. To this end, the effect of mechanical stretch on the development of engineered blood vessels was analyzed in constructs grown from porcine vascular smooth muscle cells. Cyclic radial distension was applied during vessel culture at three rates: 0 beats per minute (bpm), 90 bpm, and 165 bpm. At the end of the 7-week culture period, harvested vessels were analyzed with respect to physical characteristics. Importantly, mechanical stretch at 165 bpm resulted in a significant increase in rupture strength in engineered constructs over nonstretched controls. Stress–strain data and maximal elastic moduli from vessels grown at the three stretch rates indicate enhanced physical properties with increasing pulse rate. In order to investigate the role of collagen cross-linking in the improved mechanical characteristics, collagen cross-link density was quantified by HPLC. Vessels grown with mechanical stretch had somewhat more collagen and higher burst pressures than nonpulsed control vessels. Pulsation did not increase collagen cross-link density. Thus, increased wall thickness and somewhat elevated collagen concentrations, but not collagen cross-link density, appeared to be responsible for increased burst strength.

Solan, Amy; Dahl, Shannon L. M.; Niklason, Laura E.

2009-01-01

225

Computerized detection of retina blood vessel using a piecewise line fitting approach  

NASA Astrophysics Data System (ADS)

Retina vessels are important landmarks in fundus images, an accurate segmentation of the vessels may be useful for automated screening for several eye diseases or systematic diseases, such as diebetes. A new method is presented for automated segmentation of blood vessels in two-dimensional color fundus images. First, a coherence filter and a followed mean filter are applied to the green channel of the image. The green channel is selected because the vessels have the maximal contrast at the green channel. The coherence filter is to enhance the line strength of the original image and the mean filter is to discard the intensity variance among different regions. Since the vessels are darker than the around tissues depicted on the image, the pixels with small intensity are then retained as points of interest (POI). A new line fitting algorithm is proposed to identify line-like structures in each local circle of the POI. The proposed line fitting method is less sensitive to noise compared to the least squared fitting. The fitted lines with higher scores are regarded as vessels. To evaluate the performance of the proposed method, a public available database DRIVE with 20 test images is selected for experiments. The mean accuracy on these images is 95.7% which is comparable to the state-of-art.

Gu, Suicheng; Zhen, Yi; Wang, Ningli; Pu, Jiantao

2013-03-01

226

[Hydro-mechanical effects on human blood vessels of rotations on a short-arm centrifuge].  

PubMed

Methods of mathematical modeling in the interests of gravitational therapy revealed a number of specific effects of the short-radius centrifuge (SRC) on human leg vessels. The concepts of local g-loads and local hydrostatic pressure during exposure to the gravitational and inertial forces have been formulated. Experimental data suggest a squared dependence of local hydrostatic pressures (including in the pathology focus) on the radius of rotation; extra asymmetric oscillations of main vessels, point to the effects of the Coriolis acceleration of blood on vascular walls. PMID:14959618

Akulov, V A; Vartbaronov, R A

2003-01-01

227

Comparison of blood vessel sealing among new electrosurgical and ultrasonic devices  

Microsoft Academic Search

Background  Bipolar electrosurgical devices and ultrasonic devices are routinely used in open and advanced laparoscopic surgery for hemostasis.\\u000a New electrosurgical and ultrasonic instruments demonstrate improved quality and efficiency in blood vessel sealing.\\u000a \\u000a \\u000a \\u000a Methods  The 5-mm laparoscopic Gyrus PKS™ Cutting Forceps (PK), Gyrus Plasma Trissector™ (GP), Harmonic Scalpel® (HS), EnSeal™ Tissue Sealing and Hemostasis System (RX), LigaSure™ V with LigaSure™ Vessel Sealing Generator

William L. Newcomb; William W. Hope; Thomas M. Schmelzer; Jessica J. Heath; H. James Norton; Amy E. Lincourt; B. Todd Heniford; David A. Iannitti

2009-01-01

228

Angioscope visualization in blood vessel using Ho:YAG laser-induced vapor bubble  

NASA Astrophysics Data System (ADS)

We proposed new method of blood removal using Ho:YAG laser(?=2.1?m)-induced water-vapor bubble to prevent distal tissue ischemia during angioscopic imaging. We successfully demonstrated capability of this blood removal method using blood-filled pocine coronary artery ex vivo. We used laser irradiation conditions of 200mJ in pulse energy and 2Hz in repetition rate. Ho:YAG laser for blood removal and flash lamp lighting for endoscopic illumination were irradiated in the porcine coronary artery through individual fiber optics. Timing of the flash lamp lightning of 2?s in duration was arranged to illuminate the maximum blood removal space, i.e. the laser induced water-vapor bubble. We successfully obtained intra-lumen view via a thin angioscope using the laser blood removal without using saline injection. We studied to determine the optimum laser-induced bubble formation which indicated the minimum invasion against the blood vessel. The time resolved photography in vitro, transient pressure measurement in vitro, and acute historogical study on irradiated vessel wall in vivo were employed for this determination.

Yamashita, Erika; Oka, Yasunobu; Kaneko, Kenji; Suga, Eriko; Arai, Tsunenori

2005-04-01

229

Ho:YAG laser irradiation in blood vessel as a vasodilator: ex vivo study  

NASA Astrophysics Data System (ADS)

We studied Ho:YAG laser irradiation in blood vessel as a vasodilator ex vivo. We thought that the Ho:YAG laser-induced bubble expansion might be able to dilate the vessel because we found the vessel wall expansion after the Ho:YAG laser irradiation, that is steady deformation, in the vessel ex vivo. There have been many reports regarding to the Ho:YAG laser irradiation in the vessel. Most of studies concentrated on the interaction between Ho:YAG laser irradiation and vessel wall to investigate side effect on Ho:YAG laser angioplasty. We proposed to use the Ho:YAG laser-induced bubble expansion as a vasodilator. We studied vasodilation effect of the Ho:YAG laser-induced bubble ex vivo. The flash lamp excited Ho:YAG laser surgical unit (IH102, NIIC, Japan) (?=2.1?m) was used. The laser energy was delivered by a silica glass fiber (outer diameter: 1000?m, core diameter: 600?m). The laser-induced bubble was generated in the extracted fresh porcine carotid artery with the warmed saline perfusion. The laser energy at the fiber tip was ranging from 170-1300mJ per pulse. Number of the laser irradiation was ranged from 20pulses to 100pulses. The outer diameter of the vessel was observed. To examine the change in mechanical properties of the vessel wall, the stress-strain curve of the laser-irradiated vessel was measured. Birefringence observation and microscopic observation of staining specimen were performed. When the laser energy was set to 1300mJ per pulse, the outer diameter of the vessel after the laser irradiation was expanded by 1.4 times comparing with that of before the laser irradiation and the dilatation effect was kept even at 10minutes after the irradiation. The elasticity modulus of the artery by collagen was changed by the laser irradiation. In the polarized microscopic observation, the brightness of the intimal side of the vessel is increased comparing with that of the normal. We think this brightness increasing may be attributed to birefringence change by the arrangement of stretched collagen fiber. We suppose it is likely to be able to use the Ho:YAG laser irradiation as a temporary vasodilater tool in spite of further study should be performed.

Nakatani, E.; Iwasaki, T.; Kaneko, K.; Shimazaki, N.; Arai, T.

2007-03-01

230

Effects of X-irradiation on artificial blood vessel wall degradation by invasive tumor cells  

SciTech Connect

Artificial vessel wall cultures, constructed by growing arterial endothelial cells on preformed layers of rat smooth muscle cells, were used to evaluate the effects of X-irradiation on tumor cell-induced tissue degradation. Bovine endothelial cells had radiation sensitivities similar to those of rat smooth muscle cells. Preirradiation of smooth muscle cells, before the addition of human fibrosarcoma (HT 1080) cells, did not increase the rate of degradation and destruction by the invasive cells. However, the degradation rate was decreased if the cultures were irradiated after the addition of HT 1080 cells. The presence of bovine endothelial cells markedly inhibited the destructive abilities of fibrosarcoma cells, but preirradiation of artificial vessel walls substantially decreased their capabilities to resist HT 1080-induced lysis. These findings suggest that the abilities of blood vessels to limit extravasation may be compromised by ionizing radiation.

Heisel, M.A.; Laug, W.E.; Stowe, S.M.; Jones, P.A.

1984-06-01

231

Preoperative Coil Embolization to Aortic Branched Vessels for Prevention of Aneurysmal Sac Enlargement Following EVAR: Early Clinical Result  

PubMed Central

Objective: Persistent Type 2 endoleaks (PT2) after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) are associated with increased adverse outcomes, including aneurysmal sac enlargement and rupture. The aim of this study was to report early clinical outcomes of coil embolization (CE) to aortic branched vessels prior to EVAR and assess the effectiveness of this strategy in terms of prevention of sac growth due to PT2. Materials and Methods: Between May 2007 and April 2012, EVAR was performed for 215 cases, divided into two groups (150 cases in Group A, before introduction of CE; 21 in Group B, receiving CE before EVAR). Early clinical outcomes were compared between groups. Results: Fifty percent of cases in Group B had a marked reduction of aneurysmal sac diameter based on multi-detector row computed tomographic angiography (MDCTA) findings at the 6-month follow-up after EVAR, whereas, only 25% of cases in Group A had shrinkage of the aneurysmal sac during the same time period after EVAR. Conclusion: This strategy has the possibility of improving late outcomes of EVAR by reducing endoleak volumes beforehand.

2013-01-01

232

Blood vessel uptake and metabolism of organic nitrates in the rat  

SciTech Connect

Recent reports have suggested that the unusual pharmacokinetics observed for nitroglycerin (NTG) and isosorbide dinitrate (ISDN) may be partially explained by extensive uptake and/or metabolism of these drugs by vascular and other extrahepatic tissues. Using the rat as an animal model, this hypothesis was examined by in vivo intravessel NTG and (/sup 14/C)ISDN infusion and injection into various vessel segments, viz. the femoral vein, inferior vena cava (IVC: lower, middle and upper) and the aorta. NTG and (/sup 14/C)ISDN concentrations were determined in these blood vessels and in plasma. Blood vessel segments nearest the input site had the greatest amounts of nitrate, whereas segments further away from the input site had progressively less nitrate, with the exception of aorta, which appeared to take up NTG less extensively, on a per weight of vessel basis, than the IVC. Blood vessel NTG concentrations (nanogram per gram) were generally higher (10-fold) and declined about twice as slowly as NTG plasma concentrations (nanograms per milliliter). (/sup 14/C)NTG and (/sup 14/C)ISDN were also incubated with cofactors in IVC, aorta, abdominal muscle, lung and liver. The amounts of nitrate metabolites formed from parent drug were larger in each extrahepatic tissue incubation than in the controls (P less than .05). The results are consistent with the hypothesis that vascular and other extrahepatic tissues can take up and/or metabolize organic nitrates. The data appear to provide a partial explanation for the large systemic clearance seen with nitrates and appear consistent with existing mechanistic hypotheses for the vascular action of these compounds.

Fung, H.L.; Sutton, S.C.; Kamiya, A.

1984-02-01

233

Casts of hepatic blood vessels: a comparison of the microcirculation of the penguin, Pygoscelis adeliae, with some common laboratory animals.  

PubMed Central

Latex casts of the hepatic blood vessels of the penguin, Pygoscelis adeliae, and of some common laboratory animals were compared. There was general similarity between the different species, but the portal venous and hepatic arterial systems of the penguin were simpler than those of other species. Measurements were made of the volume and length of portal veins and it appears that the portal venous system is capable of being a more efficient blood reservoir in the penguin than in other species studied. The peribiliary plexus was especially well formed in the penguin and was drained by long veins which usually joined portal venous branches. Some of the long veins drained directly into the hepatic venous tree: these translobular veins were more prominent than in mammals. Anastomoses between hepatic artery and portal vein were not present in penguins, and the supply to the sinusoids appeared to be separate. The morphology of small hepatic veins of all the species appeared to be similar. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6

Andrews, C J; Andrews, W H

1976-01-01

234

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot  

PubMed Central

The treatment of diseased vasculature remains challenging, in part because of the difficulty in implanting drug-eluting devices without subjecting vessels to damaging mechanical forces. Implanting materials using adhesive forces could overcome this challenge, but materials have previously not been shown to durably adhere to intact endothelium under blood flow. Marine mussels secrete strong underwater adhesives that have been mimicked in synthetic systems. Here we develop a drug-eluting bioadhesive gel that can be locally and durably glued onto the inside surface of blood vessels. In a mouse model of atherosclerosis, inflamed plaques treated with steroid-eluting adhesive gels had reduced macrophage content and developed protective fibrous caps covering the plaque core. Treatment also lowered plasma cytokine levels and biomarkers of inflammation in the plaque. The drug-eluting devices developed here provide a general strategy for implanting therapeutics in the vasculature using adhesive forces and could potentially be used to stabilize rupture-prone plaques.

Kastrup, Christian J.; Nahrendorf, Matthias; Figueiredo, Jose Luiz; Lee, Haeshin; Kambhampati, Swetha; Lee, Timothy; Cho, Seung-Woo; Gorbatov, Rostic; Iwamoto, Yoshiko; Dang, Tram T.; Dutta, Partha; Yeon, Ju Hun; Cheng, Hao; Pritchard, Christopher D.; Vegas, Arturo J.; Siegel, Cory D.; MacDougall, Samantha; Okonkwo, Michael; Thai, Anh; Stone, James R.; Coury, Arthur J.; Weissleder, Ralph; Langer, Robert; Anderson, Daniel G.

2012-01-01

235

Integrin-Mediated Cell-Matrix Interaction in Physiological and Pathological Blood Vessel Formation  

PubMed Central

Physiological as well as pathological blood vessel formation are fundamentally dependent on cell-matrix interaction. Integrins, a family of major cell adhesion receptors, play a pivotal role in development, maintenance, and remodeling of the vasculature. Cell migration, invasion, and remodeling of the extracellular matrix (ECM) are integrin-regulated processes, and the expression of certain integrins also correlates with tumor progression. Recent advances in the understanding of how integrins are involved in the regulation of blood vessel formation and remodeling during tumor progression are highlighted. The increasing knowledge of integrin function at the molecular level, together with the growing repertoire of integrin inhibitors which allow their selective pharmacological manipulation, makes integrins suited as potential diagnostic markers and therapeutic targets.

Niland, Stephan; Eble, Johannes A.

2012-01-01

236

[The formation of new blood vessels in coronary artery disease: where we are now].  

PubMed

New blood vessel formation is of great importance to clinicians and researchers because of its participation in many diseases. Scientists are trying to exploit the mechanisms of vasculogenesis, angiogenesis, and arteriogenesis in the treatment of coronary artery disease. These mechanisms are employed to improve myocardium vascularization in patients where both pharmacological therapy and available revascularization procedures (PTCA, CABG) are not effective. In such cases, factors including vascular endothelial growth factor (VEGF), acid fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), granulocyte/macrophage colony-stimulating factor (GM-CSF), and granulocyte colony stimulating factor (G-CSF), as well as stem cells, have been applied so far. This article is a review of the current knowledge about new blood vessel formation, especially in ischemic myocardium. We have also analyzed alternative strategies of treating coronary artery disease using the mechanisms of angiogenesis, arteriogenesis, and vasculogenesis. PMID:15536393

Pawlak, Joanna; Klim, Beata; Szkudlarek, Magdalena; Dziecio?, Janusz

2004-01-01

237

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot.  

PubMed

The treatment of diseased vasculature remains challenging, in part because of the difficulty in implanting drug-eluting devices without subjecting vessels to damaging mechanical forces. Implanting materials using adhesive forces could overcome this challenge, but materials have previously not been shown to durably adhere to intact endothelium under blood flow. Marine mussels secrete strong underwater adhesives that have been mimicked in synthetic systems. Here we develop a drug-eluting bioadhesive gel that can be locally and durably glued onto the inside surface of blood vessels. In a mouse model of atherosclerosis, inflamed plaques treated with steroid-eluting adhesive gels had reduced macrophage content and developed protective fibrous caps covering the plaque core. Treatment also lowered plasma cytokine levels and biomarkers of inflammation in the plaque. The drug-eluting devices developed here provide a general strategy for implanting therapeutics in the vasculature using adhesive forces and could potentially be used to stabilize rupture-prone plaques. PMID:23236189

Kastrup, Christian J; Nahrendorf, Matthias; Figueiredo, Jose Luiz; Lee, Haeshin; Kambhampati, Swetha; Lee, Timothy; Cho, Seung-Woo; Gorbatov, Rostic; Iwamoto, Yoshiko; Dang, Tram T; Dutta, Partha; Yeon, Ju Hun; Cheng, Hao; Pritchard, Christopher D; Vegas, Arturo J; Siegel, Cory D; MacDougall, Samantha; Okonkwo, Michael; Thai, Anh; Stone, James R; Coury, Arthur J; Weissleder, Ralph; Langer, Robert; Anderson, Daniel G

2012-12-11

238

In Vivo ?PIV Measurements of Blood Flow in Small Vessels of a Rat Model.  

NASA Astrophysics Data System (ADS)

Ongoing research at the University of Wisconsin Medical School is addressing the effects of perfusion of glottal tissue on voice production. Building on the approach developed by Gharib's group at CalTech for embryonic zebra fish, we have modified ?PIV to measure flow in capillaries and small blood vessels in a live rat model. In lieu of seeding particles, the DPIV correlation algorithm tracks the motion of red blood cells moving through these vessels. The methodology will be presented along with a video sequence showing measurements made from muscle tissue laid nominally flat on a microscope stage. Challenges of measurements in three-dimensional geometries, i.e. the throat, will be discussed.

Wei, Timothy; Conner, Nadine; Russell, John; Legac, Paul

2007-11-01

239

Blood vessel staining in the myocardium for 3D visualization down to the smallest capillaries  

NASA Astrophysics Data System (ADS)

Blood vessels formed after medical interventions such as radiofrequency treatment have to be visualized down to the capillary level with diameters of about 5 ?m to validate neo-vascularization. Synchrotron radiation-based micro-computed tomography (SR?CT) provides the necessary spatial resolution. Since both the vessels and the surrounding tissue mainly consist of water the difference in absorption is extremely weak. Therefore, it is necessary to search for appropriate contrast agents and to develop suitable staining protocols, which finally allow segmenting the vessel tree. Among the contrast agents used in medicine lyophilic salts with a mean particle diameter of 1.5 ?m such as CaSO4, SrSO4 and BaSO4 are most appropriate to stain the vessels. The combination of these salts with a commercially available embedding kit (JB-4, Polysciences Inc.) allows tissue fixation and long-term storage in solid state. Intensity-based segmentation algorithms enable the vessel tree extraction in selected parts of the stained myocardium using the SR?CT data.

Müller, Bert; Fischer, Jens; Dietz, Ulrich; Thurner, Philipp J.; Beckmann, Felix

2006-05-01

240

A pulsatile blood vessel system for a femoral arterial access clinical simulation model.  

PubMed

The model-based, rapid-prototyping-enabled design and manufacture of a pulsatile blood vessel (PBV) for high-fidelity mannequin-based clinical simulations is presented. The PBV presented here is a pressurized, flexible tube with alternating fluid pressure created by a pump to mimic the behavior of a human vessel in response to pulsatile pressure. The use of PBVs is important for the fidelity of a clinical simulator that requires residents to palpate and/or access the vessel. In this study, a PBV is presented which features the integration of 3D modeling using patient-specific computed tomography (CT) data, mold fabrication using rapid-prototyping, and finite element method for estimating the required pumping pressure to generate the same level of force (about 1.5 N) experienced by the user through palpation. The relationship between this palpation force and the vessel pressure is studied using two strategies: finite element analysis (FEA) and experiments in a femoral arterial access simulator with a pump, artificial vessel, and surrounding phantom tissue. The experimental results show a discrepancy of 8.7% from the FEA-predicted value. Qualitative validation is done by exposing and surveying 19 interventional cardiology residents at four major educational institutions to the simulator for accuracy of its feel. The overall survey results are positive. PMID:23688608

Miller, Scott F; Sanz-Guerrero, Jorge; Dodde, Robert E; Johnson, Daniel D; Bhawuk, Atma; Gurm, Hitinder S; Shih, Albert J

2013-05-18

241

CURVES: Curve evolution for vessel segmentation  

Microsoft Academic Search

The vasculature is of utmost importance in neurosurgery. Direct visualization of images acquired with current imaging modalities, however, cannot provide a spatial representation of small vessels. These vessels, and their branches which show considerable variations, are most important in planning and performing neurosurgical procedures. In planning they provide information on where the lesion draws its blood supply and where it

Liana M. Lorigo; Olivier D. Faugeras; W. Eric L. Grimson; Renaud Keriven; Ron Kikinis; Arya Nabavi; Carl-Fredrik Westin

2001-01-01

242

Computational Geometry for Patient-Specific Reconstruction and Meshing of Blood Vessels from Angiography  

Microsoft Academic Search

Investigation of three-dimensional (3-D) geometry and fluid-dynamics in human arteries is an important issue in vascular disease characterization and assessment. Thanks to recent advances in magnetic resonance (MR) and computed tomography (CT), it is now possible to address the problem of patient-specific modeling of blood vessels, in order to take into account interindividual anatomic variability of vasculature. Generation of models

Luca Antiga; Bogdan Ene-iordache; Andrea Remuzzi

2003-01-01

243

Effect of proton beam on blood vessel formation in early developing zebrafish ( Danio rerio ) embryos  

Microsoft Academic Search

Proton beam therapy can kill tumor cells while saving normal cells because of its specific energy delivery properties and\\u000a so is used to various tumor patients. However, the effect of proton beam on angiogenesis in the development of blood vessels\\u000a has not been determined. Here we used the zebrafish model to determine in vivo whether proton beam inhibits angiogenesis. Flk-1-GFP

Gun Hyuk Jang; Ji-Hong Ha; Tae-Lin Huh; You Mie Lee

2008-01-01

244

SpatioYtemporal VEGF and PDGF Delivery Patterns Blood Vessel Formation and Maturation  

Microsoft Academic Search

Purpose. Biological mechanisms of tissue regeneration are often complex, involving the tightly coordinated spatial and temporal presentation of multiple factors. We investigated whether spatially compartmentalized and sequential delivery of factors can be used to pattern new blood vessel formation. Materials and Methods. A porous bi-layered poly(lactideYco-glycolide) (PLG) scaffold system was used to locally present vascular endothelial growth factor (VEGF) alone

Ruth R. Chen; Eduardo A. Silva; William W. Yuen; David J. Mooney

2007-01-01

245

The mathematical formulation of a generalized Hooke's law for blood vessels  

Microsoft Academic Search

It is well known that the stress–strain relationship of blood vessels is highly nonlinear. To linearize the relationship, the Hencky strain tensor is generalized to a logarithmic–exponential (log–exp) strain tensor to absorb the nonlinearity. A quadratic nominal strain potential is proposed to derive the second Piola–Kirchhoff stresses by differentiating the potential with respect to the log–exp strains. The resulting constitutive

Wei Zhang; Chong Wang; Ghassan S. Kassab

2007-01-01

246

Emory University researchers find new pathway for regulation of blood vessel growth in cancer  

Cancer.gov

Researchers at Winship Cancer Institute of Emory University have identified a new function for a gene that normally prevents the development of cancer. Scientists had known that the gene, which encodes a protein called p14 ARF, works inside the cell to control proliferation and division. The Winship team discovered that p14 ARF also regulates tumor-induced angiogenesis, the process by which growing cancers attract new blood vessels.

247

The carina angle-new geometrical parameter associated with periprocedural side branch compromise and the long-term results in coronary bifurcation lesions with main vessel stenting only.  

PubMed

Background:The two main problems unresolved in coronary bifurcation stenting are periprocedural side branch compromise and higher restenosis at long term. The purpose of this study is to reveal the link between periprocedural side branch compromise and long-term results after main vessel stenting only in coronary bifurcations. Methods:Eighty-four patients formed the study population. The inclusion criteria were good-quality angiograms, with maximal between-branch angle opening, no overlap, permitting accurate angiographic analysis. Carina angle (alpha)-the distal angle between main vessel (MV) before bifurcation and side branch (SB)-was measured pre- and poststenting. Clinical follow-up 9-12 months was obtained with coronary angiography if needed. Results:The patient population was high-risk with 33% diabetics and 84% two- and three-vessel disease. Ninety-five stents were implanted in 92 lesions, with three T-stenting cases. Drug-eluting stents were implanted in 54%. Kissing-balloon (KBI) or sequential inflation was performed in 35%. SB functional closure occurred in 17.4%, with independent predictors alpha < 40 degrees and diameter ratio MB/SB >1.22. After 12+/-4 months there were five myocardial infarctions (6%) and 13 (15%) target lesion revascularization procedures. Independent predictors of major cardiovascular events were carina angle <40 degrees , MB lesion length >8 mm, negative change of between-branch angle, DES usage, and KBI. Conclusions:Smaller carina angle with straightening of MV-main branch from stent implantation in coronary bifurcations predicted higher SB compromise, restenosis, and MACE rates during follow-up of 1 year. PMID:19702678

Gil, Robert J; Vassilev, Dobrin; Formuszewicz, Radoslaw; Rusicka-Piekarz, Teresa; Doganov, Alexander

2009-08-20

248

Note: Reflection-type micro multipoint laser Doppler velocimeter for measuring velocity distributions in blood vessels  

NASA Astrophysics Data System (ADS)

We have developed a laser Doppler velocimeter (LDV) for measuring velocity distributions in blood vessels. We converted a transmission-based LDV into a reflection-based LDV to make it suitable for clinical applications. The velocity distribution image of a serpentine flow channel obtained could be qualitatively explained by the numerical results. Finally, we evaluated the system by using it to measure injection of blood into a glass tube by a syringe pump. The results obtained demonstrate that erythrocytes can be used as seeding particles for the reflection-type micro multipoint LDV. The results obtained are useful as basic data for clinical applications.

Ishida, H.; Kobayashi, D.; Shirakawa, H.; Andoh, T.; Akiguchi, S.; Wakisaka, T.; Ishizuka, M.; Hachiga, T.

2011-07-01

249

Development of blood vessel-related radiation damage in the fimbria of the central nervous system  

SciTech Connect

The identification problem of the dose-limiting tissue component was investigated in the CNS of rats. Moderate single doses of radiation, ranging from 20 to 25 Gy were applied to the brain of adult female rats. The sequence of events was analyzed by scoring a series of morphological changes in one of the white matter structures that appears to represent a sensitive location, that is the fimbria hippocampi. The previously defined Tissue Injury Unit, characterized by a dilation of the blood vessel lumen, a thickening of the blood vessel wall, an enlargement of endothelial cell nuclei, and a hypertrophy of the adjacent astrocytes which represents a combined score of four different, but related histological changes, proved to be slightly more sensitive and responsive than the earliest recognizable changes in the neurological structures, that is demyelination. In addition, the incidence of demyelination could be expressed as a function of the intensity of the Tissue Injury Unit. These findings can be interpreted as an additional indication that blood vessel changes and the hypertrophy of the perivascular astrocytes precede degenerative changes in the white matter of the CNS after moderate doses of X rays.

Reinhold, H.S.; Calvo, W.; Hopewell, J.W.; van der Berg, A.P. (Radiobiological Institute TNO, Rijswijk (Netherland))

1990-01-01

250

L-DOPA Uptake in Astrocytic Endfeet Enwrapping Blood Vessels in Rat Brain  

PubMed Central

Astrocyte endfeet surround brain blood vessels and can play a role in the delivery of therapeutic drugs for Parkinson's disease. However, there is no previous evidence of the presence of LAT transporter for L-DOPA in brain astrocytes except in culture. Using systemic L-DOPA administration and a combination of patch clamp, histochemistry and confocal microscopy we found that L-DOPA is accumulated mainly in astrocyte cell bodies, astrocytic endfeet surrounding blood vessels, and pericytes. In brain slices: (1) astrocytes were exposed to ASP+, a fluorescent monoamine analog of MPP+; (2) ASP+ taken up by astrocytes was colocalized with L-DOPA fluorescence in (3) glial somata and in the endfeet attached to blood vessels; (4) these astrocytes have an electrogenic transporter current elicited by ASP+, but intriguingly not by L-DOPA, suggesting a different pathway for monoamines and L-DOPA via astrocytic membrane. (5) The pattern of monoamine oxidase (MAO type B) allocation in pericytes and astrocytic endfeet was similar to that of L-DOPA accumulation. We conclude that astrocytes control L-DOPA uptake and metabolism and, therefore, may play a key role in regulating brain dopamine level during dopamine-associated diseases. These data also suggest that different transporter mechanisms may exist for monoamines and L-DOPA.

Inyushin, M. Y.; Huertas, A.; Kucheryavykh, Y. V.; Kucheryavykh, L. Y.; Tsydzik, V.; Sanabria, P.; Eaton, M. J.; Skatchkov, S. N.; Rojas, L. V.; Wessinger, W. D.

2012-01-01

251

Neurovascular Signals Suggest a Propagation Mechanism for Endogenous Stem Cell Activation Along Blood Vessels  

PubMed Central

Stem cell – based therapies for central nervous system disorders are intensely pursued. Such approaches can be divided into two categories: Transplantation-based, and those that aim to pharmacologically target the endogenous stem cell population in the tissue. Endogenous stem cell – based strategies avoid the problem of immune incompatibility between the host and the grafted cells. They also avoid the placement of a large amount of cells in confined areas, a manipulation which alters the characteristics of the neurovascular microenvironment. We show here that massive pharmacological activation (increase in cell numbers) of the endogenous neural stem cell population in the adult rodent brain maintains the cytoarchitecture of the neurovascular niche. Distances between adjacent stem cells (identified by expression of Hes3) are maintained above a minimum. Hes3+ cells maintain their physical association with blood vessels. These results also suggest a mechanism by which the activation signal from the lateral ventricle can be propagated to areas a long distance away from the lateral ventricles, through autocrine/paracrine actions between adjacent Hes3+ cells, along blood vessels. Finally, powerful effects of angiopoietin 2 on Hes3+ cells help explain the prevalence of proliferating endogenous neural stem cells close to the subventricular zone (an area of high angiopoietin 2 concentration) and the quiescent state of stem cells away from the ventricles and their tight physical association with blood vessels (which express high levels of angiopoietin 1, a cytokine that opposes angiopoietin 2 functions).

Masjkur, Jimmy; Rueger, Maria Adele; Bornstein, Stefan R; McKay, Ron; Androutsellis-Theotokis, Andreas

2012-01-01

252

Nitric oxide control of lower vertebrate blood vessels by vasomotor nerves.  

PubMed

In mammals, much is understood about the endothelial and neural NO control mechanisms in the vasculature. In contrast, NO control of blood vessels in lower vertebrates is poorly understood, with the majority of research focusing on the presence of an endothelial NO system; however, its presence remains controversial. This study examined the mechanisms by which NO regulates the large blood vessels of non-mammalian vertebrates. In all species examined, the arteries and veins contained a plexus of NOS-positive perivascular nerves that included nerve bundles and fine, varicose nerve terminals. However, in the large arteries and veins of various species of fishes and amphibians, no anatomical evidence was found for endothelial NOS using both NADPH-diaphorase and eNOS immunohistochemistry. In contrast, perinuclear NOS staining was readily apparent in blue-tongue lizard, pigeon and rat, which suggested that eNOS first appeared in reptiles. Physiological analysis of NO signalling in the vascular smooth muscle of short-finned eel and cane toad could not find any evidence for endothelial NO signalling. In contrast, it appears that activation of the nitrergic vasomotor nerves is responsible for NO control of the blood vessels. PMID:16139537

Donald, John A; Broughton, Brad R S

2005-08-31

253

Blood vessels are concentrated within the implant surface concavities: a histologic study in rabbit tibia.  

PubMed

Angiogenesis plays a key role in bone formation and maintenance. Bone formation has been reported to initiate in the concavities rather than the convexities in a hydroxyapatite substratum and the implant threads of dental implants. The aim of the present study was to evaluate the number of the blood vessels inside the concavities and around the convexities of the threads of implants in a rabbit tibia model. A total of 32 thread-shaped implants blasted with apatitic calcium phosphate (TCP/HA blend) (Resorbable Blast Texturing, RBT) (Maestro, BioHorizons(®), Birmingham, AL, USA) were inserted in 8 rabbits. Each rabbit received 4 implants, 2 in the right and 2 in left tibia. Implants were retrieved after 1, 2, 4, and 8 weeks and treated to obtain thin ground sections. Statistically significant differences were found in the number of vessels that had formed in the concavities rather than the convexities of the implants after 1 (p = 0.000), and 2 weeks (p = 0.000), whilst no significant differences after 4 (p = 0.546) and 8 weeks (p = 0.275) were detected. The present results supported the hypothesis that blood vessel formation was stimulated by the presence of the concavities, which may provide a suitable environment in which mechanical forces, concentrations and gradients of chemotactic molecules and blood clot retention may all drive vascular and bone cell migration. PMID:23783569

Scarano, Antonio; Perrotti, Vittoria; Artese, Luciano; Degidi, Marco; Degidi, Davide; Piattelli, Adriano; Iezzi, Giovanna

2013-06-20

254

Accessing the structure and function information of deep skin blood vessels with noninvasive optical method  

NASA Astrophysics Data System (ADS)

The occurrence, development and curative effect of many diseases are relative to the structure and function of hypodermic blood vessels. The optical imaging techniques may be available, but suffer from the limited penetration of visible and near infrared light caused by the high scattering of skin. The tissue optical clearing technique based on immersion of tissues into optical clearing agents (OCAs), proposed by Tuchin, can improve the depth to which light penetrates. However, it is still difficult to meet skin in vivo except for OCAs hypodermic injection. In this study, THIAZONE as a new penetration enhancer mixed with polyethylene glycol (PEG-400), was typically applied to rats' skin in vivo. The optical clearing process of skin was monitored with CCD camera, and the deep blood flow information of skin was acquired by using of laser speckle contrast imaging technique. The results show that the skin became transparent after 12 minutes, the vessels were clear. After 40 minutes, acting saline on the interested region, we observed a recovery of the skin. This work is very significant for medical diagnosis since it is able to acquire the structure and function information of blood vessels in deep skin in vivo with non-invasive optical method.

Wang, Jing; Zhi, Zhongwei; Han, Zhenzhen; Liu, Caihua; Mao, Zongzhen; Wen, Xiang; Zhu, Dan

2009-02-01

255

Transcranial imaging of functional cerebral hemodynamic changes in single blood vessels using in vivo photoacoustic microscopy.  

PubMed

Optical imaging of changes in total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO(2)) provides a means to investigate brain hemodynamic regulation. However, high-resolution transcranial imaging remains challenging. In this study, we applied a novel functional photoacoustic microscopy technique to probe the responses of single cortical vessels to left forepaw electrical stimulation in mice with intact skulls. Functional changes in HbT, CBV, and SO(2) in the superior sagittal sinus and different-sized arterioles from the anterior cerebral artery system were bilaterally imaged with unambiguous 36 × 65-?m(2) spatial resolution. In addition, an early decrease of SO(2) in single blood vessels during activation (i.e., 'the initial dip') was observed. Our results indicate that the initial dip occurred specifically in small arterioles of activated regions but not in large veins. This technique complements other existing imaging approaches for the investigation of the hemodynamic responses in single cerebral blood vessels. PMID:22472612

Liao, Lun-De; Lin, Chin-Teng; Shih, Yen-Yu I; Duong, Timothy Q; Lai, Hsin-Yi; Wang, Po-Hsun; Wu, Robby; Tsang, Siny; Chang, Jyh-Yeong; Li, Meng-Lin; Chen, You-Yin

2012-04-04

256

Transcranial imaging of functional cerebral hemodynamic changes in single blood vessels using in vivo photoacoustic microscopy  

PubMed Central

Optical imaging of changes in total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2) provides a means to investigate brain hemodynamic regulation. However, high-resolution transcranial imaging remains challenging. In this study, we applied a novel functional photoacoustic microscopy technique to probe the responses of single cortical vessels to left forepaw electrical stimulation in mice with intact skulls. Functional changes in HbT, CBV, and SO2 in the superior sagittal sinus and different-sized arterioles from the anterior cerebral artery system were bilaterally imaged with unambiguous 36 × 65-?m2 spatial resolution. In addition, an early decrease of SO2 in single blood vessels during activation (i.e., ‘the initial dip') was observed. Our results indicate that the initial dip occurred specifically in small arterioles of activated regions but not in large veins. This technique complements other existing imaging approaches for the investigation of the hemodynamic responses in single cerebral blood vessels.

Liao, Lun-De; Lin, Chin-Teng; Shih, Yen-Yu I; Duong, Timothy Q; Lai, Hsin-Yi; Wang, Po-Hsun; Wu, Robby; Tsang, Siny; Chang, Jyh-Yeong; Li, Meng-Lin; Chen, You-Yin

2012-01-01

257

A Heat-Shock Protein Axis Regulates VEGFR2 Proteolysis, Blood Vessel Development and Repair  

PubMed Central

Vascular endothelial growth factor A (VEGF-A) binds to the VEGFR2 receptor tyrosine kinase, regulating endothelial function, vascular physiology and angiogenesis. However, the mechanism underlying VEGFR2 turnover and degradation in this response is unclear. Here, we tested a role for heat-shock proteins in regulating the presentation of VEGFR2 to a degradative pathway. Pharmacological inhibition of HSP90 stimulated VEGFR2 degradation in primary endothelial cells and blocked VEGF-A-stimulated intracellular signaling via VEGFR2. HSP90 inhibition stimulated the formation of a VEGFR2-HSP70 complex. Clathrin-mediated VEGFR2 endocytosis is required for this HSP-linked degradative pathway for targeting VEGFR2 to the endosome-lysosome system. HSP90 perturbation selectively inhibited VEGF-A-stimulated human endothelial cell migration in vitro. A mouse femoral artery model showed that HSP90 inhibition also blocked blood vessel repair in vivo consistent with decreased endothelial regeneration. Depletion of either HSP70 or HSP90 caused defects in blood vessel formation in a transgenic zebrafish model. We conclude that perturbation of the HSP70-HSP90 heat-shock protein axis stimulates degradation of endothelial VEGFR2 and modulates VEGF-A-stimulated intracellular signaling, endothelial cell migration, blood vessel development and repair.

Bruns, Alexander F.; Yuldasheva, Nadira; Latham, Antony M.; Bao, Leyuan; Pellet-Many, Caroline; Frankel, Paul; Stephen, Sam L.; Howell, Gareth J.; Wheatcroft, Stephen B.; Kearney, Mark T.; Zachary, Ian C.; Ponnambalam, Sreenivasan

2012-01-01

258

The Emergence of Blood and Blood Vessels in the Embryo and Its Relevance to Postnatal Biology and Disease  

NASA Astrophysics Data System (ADS)

Blood and blood vessels develop in parallel within mammalian systems, and this temporal and spatial association has led to the confirmation of an endothelial origin of hematopoiesis. The extraembryonic yolk sac and aorto-gonado-mesonephros (AGM) region both contain a specialized population of endothelial cells ("hemogenic endothelium") that function to produce hematopoietic stem and progenitor cells, which then differentiate to provide the full complement of blood cells within the developing embryo and furthermore in the adult system. Therefore, this population has great therapeutic potential in the fields of regenerative medicine and tissue engineering. This chapter reviews the development of the vascular and hematopoietic systems, characterization and function of the hemogenic endothelium within embryonic and embryonic stem cell (ES cell) models, and speculate on the presence of such a population within the adult system. In order to harness this endothelial subtype for clinical application, we must understand both the normal functions of these cells and the potential for misregulation in disease states.

Sills, Tiffany M.; Hirschi, Karen K.

259

Advances in probing the blood vessels of the human brain using magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging offers a marvelous means to probe the vasculature of the human body non-invasively. The first major advances came when the physics of the effects of motion in MRI were first understood well enough that new methods could be designed to compensate for the motion. This led to the development of MR angiography. The second major advance occurred when a contrast agent was used to enhance the signal from vessels independent of blood flow. This made it possible to image much smaller vessels because of the increased signal-to-noise ratio. The third major advance occurred when the susceptibility of the venous blood was used to create a new contrast unique to veins even in the presence of the contrast agent to enhance their signal. The fourth advance is close behind with the potential to use the susceptibility to measure the local oxygen content. Each of these advances involved some interesting physics and raised questions about local magnetic field effects, some of which remain unanswered yet today. We will show results from the first three levels with hints at how to proceed to the fourth. The development of this technology has important clinical implications. With new higher relaxivity contrast agents and higher field magnets coming on the market, the possibility to image vessels down to on the order of 100 microns may be viable. Each advance has enhanced the range of applications from just imaging vessels to occult vascular disease, trauma, the detection of blood products, and physiologic function of the tissue itself.

Haacke, E. Mark

2002-03-01

260

A histochemical study of the innervation of cerebral blood vessels in the snake.  

PubMed

Dual innervation of snake cerebral blood vessels by adrenergic and cholinergic fibres was demonstrated with the use of histochemical methods. Although the nerve plexuses are somewhat less dense, the essential features of innervation of the blood vessels are similar to those of mammals with the exception that the adrenergic plexuses are more prominent than the cholinergic plexuses. The major arteries of the cerebral carotid system have a rich nerve supply. However, the innervation is less rich in the basilar and poor in the spinal (vertebral) arteries. Although the arteries supplying the right side of head are poorly developed, three pairs of arteries, cerebral carotids, ophthalmics and spinals, supply the snake brain. The carotids and ophthalmics are densely innervated and are accompanied by thick nerve bundles, suggesting that the nerves preferentially enter the skull along those arteries. Some parenchymal arterioles are also dually innervated. Connection between the brain parenchyma and intracerebral capillaries via both cholinergic and adrenergic fibres was observed. In addition cholinergic nerve fibers, connecting capillaries and the intramedullary nerve fibre bundles, were noticed. Capillary blood flow may be influenced by both adrenergic and cholinergic central neurons. The walls of capillaries also exhibit heavy acetylcholinesterase activity. This may indicate an important role for the capillary in the regulation of intracerebral blood flow. PMID:870209

Iijima, T; Wasano, T; Tagawa, T; Ando, K

1977-04-01

261

Dynamic Quantitative Intravital Imaging of Glioblastoma Progression Reveals a Lack of Correlation between Tumor Growth and Blood Vessel Density.  

PubMed

The spatiotemporal and longitudinal monitoring of cellular processes occurring in tumors is critical for oncological research. We focused on glioblastoma multiforme (GBM), an untreatable highly vascularized brain tumor whose progression is thought to critically depend on the oxygen and metabolites supplied by blood vessels. We optimized protocols for orthotopic GBM grafting in mice that were able to recapitulate the biophysical constraints normally governing tumor progression and were suitable for intravital multiphoton microscopy. We repeatedly imaged tumor cells and blood vessels during GBM development. We established methods for quantitative correlative analyses of dynamic imaging data over wide fields in order to cover the entire tumor. We searched whether correlations existed between blood vessel density, tumor cell density and proliferation in control tumors. Extensive vascular remodeling and the formation of new vessels accompanied U87 tumor cell growth, but no strong correlation was found between local cell density and the extent of local blood vessel density irrespective of the tumor area or time points. The technique moreover proves useful for comparative analysis of mice subjected either to Bevacizumab anti-angiogenic treatment that targets VEGF or to AMD3100, an antagonist of CXCR4 receptor. Bevacizumab treatment massively reduced tumoral vessel densities but only transiently reduced U87 tumor growth rate. Again, there was no correlation between local blood vessel density and local cell density. Moreover, Bev applied only prior to tumor implantation inhibited tumor growth to the same extent as post-grafting treatment. AMD3100 achieved a potent inhibition of tumor growth without significant reduction in blood vessel density. These results indicate that in the brain, in this model, tumor growth can be sustained without an increase in blood vessel density and suggest that GBM growth is rather governed by stromal properties. PMID:24069154

Ricard, Clément; Stanchi, Fabio; Rodriguez, Thieric; Amoureux, Marie-Claude; Rougon, Geneviève; Debarbieux, Franck

2013-09-12

262

Dynamic Quantitative Intravital Imaging of Glioblastoma Progression Reveals a Lack of Correlation between Tumor Growth and Blood Vessel Density  

PubMed Central

The spatiotemporal and longitudinal monitoring of cellular processes occurring in tumors is critical for oncological research. We focused on glioblastoma multiforme (GBM), an untreatable highly vascularized brain tumor whose progression is thought to critically depend on the oxygen and metabolites supplied by blood vessels. We optimized protocols for orthotopic GBM grafting in mice that were able to recapitulate the biophysical constraints normally governing tumor progression and were suitable for intravital multiphoton microscopy. We repeatedly imaged tumor cells and blood vessels during GBM development. We established methods for quantitative correlative analyses of dynamic imaging data over wide fields in order to cover the entire tumor. We searched whether correlations existed between blood vessel density, tumor cell density and proliferation in control tumors. Extensive vascular remodeling and the formation of new vessels accompanied U87 tumor cell growth, but no strong correlation was found between local cell density and the extent of local blood vessel density irrespective of the tumor area or time points. The technique moreover proves useful for comparative analysis of mice subjected either to Bevacizumab anti-angiogenic treatment that targets VEGF or to AMD3100, an antagonist of CXCR4 receptor. Bevacizumab treatment massively reduced tumoral vessel densities but only transiently reduced U87 tumor growth rate. Again, there was no correlation between local blood vessel density and local cell density. Moreover, Bev applied only prior to tumor implantation inhibited tumor growth to the same extent as post-grafting treatment. AMD3100 achieved a potent inhibition of tumor growth without significant reduction in blood vessel density. These results indicate that in the brain, in this model, tumor growth can be sustained without an increase in blood vessel density and suggest that GBM growth is rather governed by stromal properties.

Ricard, Clement; Stanchi, Fabio; Rodriguez, Thieric; Amoureux, Marie-Claude; Rougon, Genevieve; Debarbieux, Franck

2013-01-01

263

S1P? localizes to the colonic vasculature in ulcerative colitis and maintains blood vessel integrity.  

PubMed

Signaling through sphingosine-1-phosphate receptor? (S1P?) promotes blood vessel barrier function. Degradation of S1P? results in increased vascular permeability in the lung and may explain side effects associated with administration of FTY720, a functional antagonist of the S1P? receptor that is currently used to treat multiple sclerosis. Ulcerative colitis (UC) is characterized by an increased density of abnormal vessels. The expression or role of S1P? in blood vessels in the colon has not been investigated. In the present study, we show that S1P? is overexpressed in the colonic mucosa of UC patients. This increase in S1P? levels reflects increased vascular density in the inflamed mucosa. Genetic deletion of S1pr1 in mice increases colonic vascular permeability under basal conditions and increases bleeding in experimental colitis. In contrast, neither FTY720 nor AUY954, two S1P receptor-targeting agents, increases bleeding in experimental colitis. Taken together, our findings demonstrate that S1P? is critical to maintaining colonic vascular integrity and may play a role in UC pathogenesis. PMID:23296878

Montrose, David C; Scherl, Ellen J; Bosworth, Brian P; Zhou, Xi Kathy; Jung, Bongnam; Dannenberg, Andrew J; Hla, Timothy

2013-01-07

264

In vivo Bioimaging as a Novel Strategy to Detect Doxorubicin-Induced Damage to Gonadal Blood Vessels  

PubMed Central

Introduction Chemotherapy may induce deleterious effects in normal tissues, leading to organ damage. Direct vascular injury is the least characterized side effect. Our aim was to establish a real-time, in vivo molecular imaging platform for evaluating the potential vascular toxicity of doxorubicin in mice. Methods Mice gonads served as reference organs. Mouse ovarian or testicular blood volume and femoral arterial blood flow were measured in real-time during and after doxorubicin (8 mg/kg intravenously) or paclitaxel (1.2 mg/kg) administration. Ovarian blood volume was imaged by ultrasound biomicroscopy (Vevo2100) with microbubbles as a contrast agent whereas testicular blood volume and blood flow as well as femoral arterial blood flow was imaged by pulse wave Doppler ultrasound. Visualization of ovarian and femoral microvasculature was obtained by fluorescence optical imaging system, equipped with a confocal fiber microscope (Cell-viZio). Results Using microbubbles as a contrast agent revealed a 33% (P<0.01) decrease in ovarian blood volume already 3 minutes after doxorubicin injection. Doppler ultrasound depicted the same phenomenon in testicular blood volume and blood flow. The femoral arterial blood flow was impaired in the same fashion. Cell-viZio imaging depicted a pattern of vessels' injury at around the same time after doxorubicin injection: the wall of the blood vessels became irregular and the fluorescence signal displayed in the small vessels was gradually diminished. Paclitaxel had no vascular effect. Conclusion We have established a platform of innovative high-resolution molecular imaging, suitable for in vivo imaging of vessels' characteristics, arterial blood flow and organs blood volume that enable prolonged real-time detection of chemotherapy-induced effects in the same individuals. The acute reduction in gonadal and femoral blood flow and the impairment of the blood vessels wall may represent an acute universal doxorubicin-related vascular toxicity, an initial event in organ injury.

Tzabari, Moran; Tsarfaty, Galia; Stemmer, Salomon M.; Shalgi, Ruth

2011-01-01

265

An accurate, convective energy equation based automated meshing technique for analysis of blood vessels and tissues.  

PubMed

An automated three-element meshing method for generating finite element based models for the accurate thermal analysis of blood vessels imbedded in tissue has been developed and evaluated. The meshing method places eight noded hexahedral elements inside the vessels where advective flows exist, and four noded tetrahedral elements in the surrounding tissue. The higher order hexahedrals are used where advective flow fields occur, since high accuracy is required and effective upwinding algorithms exist. Tetrahedral elements are placed in the remaining tissue region, since they are computationally more efficient and existing automatic tetrahedral mesh generators can be used. Five noded pyramid elements connect the hexahedrals and tetrahedrals. A convective energy equation (CEE) based finite element algorithm solves for the temperature distributions in the flowing blood, while a finite element formulation of a generalized conduction equation is used in the surrounding tissue. Use of the CEE allows accurate solutions to be obtained without the necessity of assuming ad hoc values for heat transfer coefficients. Comparisons of the predictions of the three-element model to analytical solutions show that the three-element model accurately simulates temperature fields. Energy balance checks show that the three-element model has small, acceptable errors. In summary, this method provides an accurate, automatic finite element gridding procedure for thermal analysis of irregularly shaped tissue regions that contain important blood vessels. At present, the models so generated are relatively large (in order to obtain accurate results) and are, thus, best used for providing accurate reference values for checking other approximate formulations to complicated, conjugated blood heat transfer problems. PMID:10763743

White, J A; Dutton, A W; Schmidt, J A; Roemer, R B

266

Application of the (G'/G)-expansion method to nonlinear blood flow in large vessels  

NASA Astrophysics Data System (ADS)

As is widely known today, Navier-Stokes equations are used to describe blood flow in large vessels. In the past several decades, and even in very recent works, these equations have been reduced to Korteweg-de Vries (KdV), modified KdV or Boussinesq equations. In this paper, we avoid such simplifications and investigate the analytical traveling wave solutions of the one-dimensional generic Navier-Stokes equations, through the (G ' /G)-expansion method. These traveling wave solutions include hyperbolic functions, trigonometric functions and rational functions. Since some of them are not yet explored in the study of blood flow, we pay attention to hyperbolic function solutions and we show that the (G ' /G)-expansion method presents a wider applicability that allows us to bring out the widely known blood flow behaviors. The biological implications of the found solutions are discussed accordingly.

Kol, Guy Richard; Bertrand Tabi, Conrad

2011-04-01

267

Fluid-structure interaction analysis on the effects of vessel material properties on blood flow characteristics in stenosed arteries under axial rotation  

Microsoft Academic Search

We conducted blood flow analysis, using the Fluid-Structure Interaction (FSI) method, to examine how changes in the material\\u000a properties of blood vessels affect blood flow characteristics, using the carotid artery as the model vessel. The geometry\\u000a of the blood vessel included 50% stenosis at the center, and blood was modeled as a non-Newtonian fluid. In order to investigate\\u000a the effects

Seong Wook Cho; Seung Wook Kim; Moon Hyun Sung; Kyoung Chul Ro; Hong Sun Ryou

2011-01-01

268

Magnetic navigation system for the precise helical and translational motions of a microrobot in human blood vessels  

NASA Astrophysics Data System (ADS)

Different magnetic navigation systems (MNSs) have been investigated for the wireless manipulation of microrobots in human blood vessels. Here we propose a MNS and methodology for generation of both the precise helical and translational motions of a microrobot to improve its maneuverability in complex human blood vessel. We then present experiments demonstrating the helical and translational motions of a spiral-type microrobot to verify the proposed MNS.

Jeon, S. M.; Jang, G. H.; Choi, H. C.; Park, S. H.; Park, J. O.

2012-04-01

269

Real-Time Color-Doppler Guidance of HIFU for the Selective Avoidance or Occlusion of Blood Vessels  

Microsoft Academic Search

High-intensity focused ultrasound (HIFU) has been shown to effectively occlude blood vessels deep within tissue. The objective of the current study was to synchronize HIFU and color-Doppler ultrasound (US) for the real-time visualization of flow within blood vessels during HIFU treatment. The excitation of the HIFU was synchronized with the color-Doppler imager by collecting the excitation pulses of one of

Brian A. Rabkin; Vesna Zderic; Shahram Vaezy

2005-01-01

270

Bidirectional LDV system for absolute measurement of blood speed in retinal vessels.  

PubMed

A laser Doppler technique which provides a means of obtaining absolute measurements of the speed of red blood cells (RBCs) flowing in individual retinal vessels is described. Doppler-shift frequency spectra of laser light scattered from the RBCs are obtained for two directions of the scattered light. Each spectrum exhibits a cutoff frequency that is directly related to the maximum RBC speed (V(max)). The difference in cutoff frequencies is used to obtain an absolute measure of V(max) that is independent of the exact orientation of the vessel and of the relative direction of the incident and scattered beams with respect to the flow direction. Preliminary measurements obtained using a prototype instrument are presented. PMID:20212650

Riva, C E; Feke, G T; Eberli, B; Benary, V

1979-07-01

271

Segmentation of Blood Vessels and 3D Representation of CMR Image  

NASA Astrophysics Data System (ADS)

Current cardiac magnetic resonance imaging (CMR) technology allows the determination of patient-individual coronary tree structure, detection of infarctions, and assessment of myocardial perfusion. The purpose of this work is to segment heart blood vessels and visualize it in 3D. In this work, 3D visualisation of vessel was performed into four phases. The first step is to detect the tubular structures using multiscale medialness function, which distinguishes tube-like structures from and other structures. Second step is to extract the centrelines of the tubes. From the centreline radius the cylindrical tube model is constructed. The third step is segmentation of the tubular structures. The cylindrical tube model is used in segmentation process. Fourth step is to 3D representation of the tubular structure using Volume . The proposed approach is applied to 10 datasets of patients from the clinical routine and tested the results with radiologists.

Jiji, G. W.

2013-06-01

272

Segmentation of Blood Vessels and 3D Representation of CMR Image  

NASA Astrophysics Data System (ADS)

Current cardiac magnetic resonance imaging (CMR) technology allows the determination of patient-individual coronary tree structure, detection of infarctions, and assessment of myocardial perfusion. The purpose of this work is to segment heart blood vessels and visualize it in 3D. In this work, 3D visualisation of vessel was performed into four phases. The first step is to detect the tubular structures using multiscale medialness function, which distinguishes tube-like structures from and other structures. Second step is to extract the centrelines of the tubes. From the centreline radius the cylindrical tube model is constructed. The third step is segmentation of the tubular structures. The cylindrical tube model is used in segmentation process. Fourth step is to 3D representation of the tubular structure using Volume . The proposed approach is applied to 10 datasets of patients from the clinical routine and tested the results with radiologists.

Jiji, G. W.

2013-08-01

273

Activation of Peripheral Opioid ?-Receptors in Blood Vessel May Lower Blood Pressure in Spontaneously Hypertensive Rats  

Microsoft Academic Search

Background\\/Aims: The role of opioid receptors in the regulation of vascular function remains unclear. In the current study, we evaluated the ability of loperamide, a peripheral opioid receptor agonist, to regulate blood pressure in spontaneously hypertensive rats (SHRs) and examined the mechanism(s) by which loperamide exerts its effects. Methods: In male SHRs, mean arterial pressure (MAP) was measured and hemodynamic

Zhih-Cherng Chen; Ja-Ping Shieh; Hsien-Hui Chung; Ching-Hsia Hung; Hung Jung Lin; Juei-Tang Cheng

2011-01-01

274

The use of near-infrared light for safe and effective visualization of subsurface blood vessels to facilitate blood withdrawal in children.  

PubMed

Obtaining access to blood vessels can be difficult, especially in children. Visualization of subsurface blood vessels might be a solution. Ultrasound and visible light have been used to this purpose, but have some drawbacks. Near-infrared light might be a better option since subsurface blood vessels can be visualized in high contrast due to less absorption and scattering in tissue as compared to visible light. Our findings with a multispectral imaging system support this theory. A device, the VascuLuminator, was developed, based on transillumination of the puncture site with near-infrared light. The VascuLuminator was designed to meet the requirements of compact and safe use. A phantom study showed that the maximum depth of visibility (5.5mm for a 3.6mm blood vessel) is sufficient to visualize blood vessels in typical locations for peripheral venous and arterial access. A quantitative comparison of the VascuLuminator and to two other vessel imaging devices, using reflection of near-infrared light instead of transillumination, was conducted. The VascuLuminator is able to decrease failure at first attempt in blood withdrawal in pediatric patients from 10/80 (13%) to 1/45 (2%; P=.05). PMID:22841651

Cuper, Natascha J; Klaessens, John H G; Jaspers, Joris E N; de Roode, Rowland; Noordmans, Herke Jan; de Graaff, Jurgen C; Verdaasdonk, Rudolf M

2012-07-27

275

Launch conditions might affect the formation of blood vessels in the quail chorioallantoic membrane.  

PubMed

As a part of the first joint USA-Russian MIR/Shuttle program, fertilized quail eggs were flown on the MIR 18 mission. Post-flight examination indicated impaired survival of both the embryos in space and also of control embryo exposed to vibrational and g-forces simulating the condition experienced during the launch of Progress 227. We hypothesized that excess mechanical forces and/or other conditions during the launch might cause abnormal development or the blood supply in the chorioallantoic membrane (CAM) leading to the impaired survival of the embryos. The CAM, a highly vascularized extraembryonic organ, provides for the oxygen exchange across the egg shell and is thus pivotal for proper embryonic development. To test our hypothesis, we compared angiogenesis in CAMs of eggs which were either exposed to the vibration and g-force profile simulating the conditions at launch of Progress 227 (synchronous controls), or kept under routine conditions in a laboratory incubator (laboratory controls). At various time points during incubation, the eggs were fixed in paraformaldehyde for subsequent dissection. At the time of dissection, the CAM was carefully lifted from the egg shell and examined as whole mounts by bright-field and fluorescent microscopy. The development of the vasculature (angiogenesis) was assessed from the density of blood vessels per viewing field and evaluated by computer aided image analysis. We observed a significant decrease in blood-vessel density in the synchronous controls versus "normal" laboratory controls beginning from day 10 of incubation. The decrease in vascular density was restricted to the smallest vessels only, suggesting that conditions during the launch and/or during the subsequent incubation of the eggs may affect the normal progress of angiogenesis in the CAM. Abnormal angiogensis in the CAM might contribute to the impaired survival of the embryos observed in synchronous controls as well as in space. PMID:11543304

Henry, M K; Unsworth, B R; Sychev, V; Guryeva, T S; Dadasheva, O A; Piert, S J; Lagel, K E; Dubrovin, L C; Jahns, G C; Boda, K; Sabo, V; Samet, M M; Lelkes, P I

1998-01-01

276

[Paravasal connective tissue of the in-wall blood vessels of the heart during aging].  

PubMed

The structural organization of the paravasal connective tissue of the in-wall myocardial blood vessels in the stages of postnatal ontogenesis was studied. The study was carried out on preparations of the heart 80 corpses of men in three age groups (the first period of adulthood (n = 20) and elderly (n = 30) and old (n = 30) ages.) The peculiarities of the structure as well as qualitative and quantitative transformation of fibrous component of the paravasal connective tissue in each age period were revealed. PMID:23734505

Nikel', V V; Kasimtsev, A A; Efremova, V P

2012-01-01

277

Spatio–temporal VEGF and PDGF Delivery Patterns Blood Vessel Formation and Maturation  

Microsoft Academic Search

\\u000a Purpose  Biological mechanisms of tissue regeneration are often complex, involving the tightly coordinated spatial and temporal presentation\\u000a of multiple factors. We investigated whether spatially compartmentalized and sequential delivery of factors can be used to\\u000a pattern new blood vessel formation.\\u000a \\u000a \\u000a \\u000a Materials and Methods  A porous bi-layered poly(lactide–co-glycolide) (PLG) scaffold system was used to locally present vascular endothelial growth\\u000a factor (VEGF) alone in one

Ruth R. Chen; Eduardo A. Silva; William W. Yuen; David J. Mooney

2007-01-01

278

Omentin, a novel adipokine, induces vasodilation in rat isolated blood vessels  

Microsoft Academic Search

Omentin is a recently identified adipose tissue-derived cytokine and is implicated in obesity-related cardiovascular disorders. In the present study, we tested the hypothesis that omentin could directly affect vascular reactivity of isolated blood vessels. In endothelium-intact rat isolated aorta, pretreatment with omentin (300ng\\/ml, 30min) inhibited noradrenaline (NA; 1nM–1?M)-induced concentration-dependent contraction. In NA (100nM)-pre-contracted aorta, omentin (1–300ng\\/ml) directly induced an endothelium-dependent

Hideyuki Yamawaki; Naoya Tsubaki; Masashi Mukohda; Muneyoshi Okada; Yukio Hara

2010-01-01

279

3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head  

NASA Astrophysics Data System (ADS)

Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

2010-03-01

280

Transcriptome-wide analysis of blood vessels laser captured from human skin and chronic wound-edge tissue  

PubMed Central

Chronic wounds represent a substantial public health problem. The development of tools that would enable sophisticated scrutiny of clinical wound tissue material is highly desirable. This work presents evidence enabling rapid specific identification and laser capture of blood vessels from human tissue in a manner which lends itself to successful high-density (U133A) microarray analysis. Such screening of transcriptome followed by real-time PCR and immunohistochemical verification of candidate genes and their corresponding products were performed by using 3 mm biopsies. Of the 18,400 transcripts and variants screened, a focused set of 53 up-regulated and 24 down-regulated genes were noted in wound-derived blood vessels compared with blood vessels from intact human skin. The mean abundance of periostin in wound-site blood vessels was 96-fold higher. Periostin is known to be induced in response to vascular injury and its expression is associated with smooth muscle cell differentiation in vitro and promotes cell migration. Forty-fold higher expression of heparan sulfate 6-O-endosulfatase1 (Sulf1) was noted in wound-site vessels. Sulf1 has been recently recognized to be anti-angiogenic. During embryonic vasculogenesis, CD24 expression is down-regulated in human embryonic stem cells. Wound-site vessels had lower CD24 expression. The findings of this work provide a unique opportunity to appreciate the striking contrast in the transcriptome composition in blood vessels collected from the intact skin and from the wound-edge tissue. Sets of genes with known vascular functions but never connected to wound healing were identified to be differentially expressed in wound-derived blood vessels paving the way for innovative clinically relevant hypotheses.

Roy, Sashwati; Patel, Darshan; Khanna, Savita; Gordillo, Gayle M.; Biswas, Sabyasachi; Friedman, Avner; Sen, Chandan K.

2007-01-01

281

Effect of physical variables on capture of magnetic nanoparticles in simulated blood vessels  

NASA Astrophysics Data System (ADS)

This study investigated how the percent capture of magnetic nanoparticles in a simulated vessel varies with physical variables. Magnetic nanoparticles (MNPs) can used as part of therapeutic or diagnostic materials for cancer patients. By capturing these devices with a magnetic field, the particles can be concentrated in an area of diseased tissue. In this study, flow of nanoparticles in simulated blood vessels was used to determine the affect of applying an external magnetic field. This study used maghemite nanoparticles as the MNPs and either water or Fetal Bovine Serum as the carrier fluid. A UV-Vis collected capture data. The percent capture of MNPs was positively influenced by five physical variables: larger vessel diameters, lower linear flow velocity, higher magnetic field strength, better dispersion, lower MNP concentration, and lower protein content in fluid. Free MNPs were also compared to micelles, with the free particles having more successful magnetic capture. Four factors contributed to these trends: the strength of the magnetic field's influence on the MNPs, the MNPs' interactions with other particles and the fluid, the momentum of the nanoparticles, and magnetic mass to total mass ratio of the flowing particles.

Zhang, Minghui; Brazel, Christopher

2011-11-01

282

Changes in Gene Expression of Pial Vessels of the Blood Brain Barrier during Murine Neurocysticercosis  

PubMed Central

In murine neurocysticercosis (NCC), caused by infection with the parasite Mesocestoides corti, the breakdown of the Blood Brain Barrier (BBB) and associated leukocyte infiltration into the CNS is dependent on the anatomical location and type of vascular bed. Prior studies of NCC show that the BBB comprised of pial vessels are most affected in comparison to the BBB associated with the vasculature of other compartments, particularly parenchymal vessels. Herein, we describe a comprehensive study to characterize infection-induced changes in the genome wide gene expression of pial vessels using laser capture microdissection microscopy (LCM) combined with microarray analyses. Of the 380 genes that were found to be affected, 285 were upregulated and 95 were downregulated. Ingenuity Pathway Analysis (IPA) software was then used to assess the biological significance of differentially expressed genes. The most significantly affected networks of genes were “inflammatory response, cell-to-cell signaling and interaction, cellular movement”, “cellular movement, hematological system development and function, immune cell trafficking, and “antimicrobial response, cell-to-cell signaling and interaction embryonic development”. RT-PCR analyses validated the pattern of gene expression obtained from microarray analysis. In addition, chemokines CCL5 and CCL9 were confirmed at the protein level by immunofluorescence (IF) microscopy. Our data show altered gene expression related to immune and physiological functions and collectively provide insight into changes in BBB disruption and associated leukocyte infiltration during murine NCC.

Mishra, Pramod Kumar; Teale, Judy M.

2013-01-01

283

Nucleolin expressed at the cell surface is a marker of endothelial cells in angiogenic blood vessels  

PubMed Central

A tumor-homing peptide, F3, selectively binds to endothelial cells in tumor blood vessels and to tumor cells. Here, we show that the cell surface molecule recognized by F3 is nucleolin. Nucleolin specifically bound to an F3 peptide affinity matrix from extracts of cultured breast carcinoma cells. Antibodies and cell surface biotin labeling revealed nucleolin at the surface of actively growing cells, and these cells bound and internalized fluorescein-conjugated F3 peptide, transporting it into the nucleus. In contrast, nucleolin was exclusively nuclear in serum-starved cells, and F3 did not bind to these cells. The binding and subsequent internalization of F3 were blocked by an antinucleolin antibody. Like the F3 peptide, intravenously injected antinucleolin antibodies selectively accumulated in tumor vessels and in angiogenic vessels of implanted “matrigel” plugs. These results show that cell surface nucleolin is a specific marker of angiogenic endothelial cells within the vasculature. It may be a useful target molecule for diagnostic tests and drug delivery applications.

Christian, Sven; Pilch, Jan; Akerman, Maria E.; Porkka, Kimmo; Laakkonen, Pirjo; Ruoslahti, Erkki

2003-01-01

284

By Different Cellular Mechanisms, Lymphatic Vessels Sprout by Endothelial Cell Recruitment Whereas Blood Vessels Grow by Vascular Expansion.  

National Technical Information Service (NTIS)

The development of effective vascular therapies requires the understanding of all modes of vessel formation contributing to vasculogenesis, angiogenesis (here termed hemangiogenesis) and lymphangiogenesis. We show that lymphangiogenesis proceeds by blind-...

P. Parsons-Wingerter T. L. McKay D. Leontiev T. K. Condrich P. E. DiCorleto

2005-01-01

285

Perivascular mast cells dynamically probe cutaneous blood vessels to capture immunoglobulin E.  

PubMed

Mast cells are tissue-resident immune cells that play a central role in allergic disease. These contributions are largely dependent on the acquisition of antigen-specific immunoglobulin E (IgE). Despite this requirement, studies of mast cell and IgE interactions have overlooked the mechanism by which mast cells acquire IgE from the blood. To address this gap, we developed reporter IgE molecules and employed imaging techniques to study mast cell function in situ. Our data demonstrate that skin mast cells exhibit selective uptake of IgE based on perivascular positioning. Furthermore, perivascular mast cells acquire IgE by extending cell processes across the vessel wall to capture luminal IgE. These data demonstrate how tissue mast cells acquire IgE and reveal a strategy by which extravascular cells monitor blood contents to capture molecules central to cellular function. PMID:23290520

Cheng, Laurence E; Hartmann, Karin; Roers, Axel; Krummel, Matthew F; Locksley, Richard M

2013-01-03

286

Fluid-structure interaction analysis on the effects of vessel material properties on blood flow characteristics in stenosed arteries under axial rotation  

NASA Astrophysics Data System (ADS)

We conducted blood flow analysis, using the Fluid-Structure Interaction (FSI) method, to examine how changes in the material properties of blood vessels affect blood flow characteristics, using the carotid artery as the model vessel. The geometry of the blood vessel included 50% stenosis at the center, and blood was modeled as a non-Newtonian fluid. In order to investigate the effects of vessel material properties, linear elastic models with 0.21 MPa, 0.51 MPa, and 1.25 MPa, which are within the typical elastic modulus range of the carotid artery, were used to simulate the blood vessel, and these were compared with the rigid body model. The difference in blood vessel elasticity caused periodic and transient changes in blood flow. The more elastic the blood vessel becomes, the longer the periods of velocity, pressure, and Wall Shear Stress (WSS) change and the smaller the size of the Fluid Recirculation Zone (FRZ). Also, transient changes in blood flow occurred due to the accumulation of differences in flow caused by vessel wall deformation. This is because a change in the stiffness of the vessel wall causes the vessel's vibration period to change, leading to changes in blood flow.

Cho, Seong Wook; Kim, Seung Wook; Sung, Moon Hyun; Ro, Kyoung Chul; Ryou, Hong Sun

2011-03-01

287

Detection of Trypanosoma brucei spp. in human blood by a nonradioactive branched DNA-based technique.  

PubMed Central

We have developed a nonradioactive branched DNA (bDNA)-based assay for the diagnosis of the African trypanosomiases in simple buffy coat preparations of human blood. Two repetitive DNA sequences specific to the Trypanosoma brucei complex were chosen as targets of the bDNA assay, a technique which amplifies the signal from a target molecule rather than the target itself. Comparable sensitivities were observed with cloned target sequences, purified T. brucei DNA, procyclic trypanosomes, and bloodstream trypomastigotes. The results of bDNA analysis of human blood samples from Côte d'Ivoire (n = 50) showed excellent agreement with those of buffy coat microscopy. The bDNA technology offers certain advantages over alternative molecular biological techniques, including the simplicity of sample preparation and of the procedure itself, the stability of the reagents, the ability to process large numbers of samples simultaneously, and freedom from crosscontamination artifacts. We have successfully applied the bDNA technique to the detection of T. brucei in clinical samples from regions where T. brucei infection is endemic; to our knowledge, this is the first report of the molecular detection of T. brucei in human blood.

Harris, E; Detmer, J; Dungan, J; Doua, F; White, T; Kolberg, J A; Urdea, M S; Agabian, N

1996-01-01

288

Investigation of the cerebral hemodynamic response function in single blood vessels by functional photoacoustic microscopy  

NASA Astrophysics Data System (ADS)

The specificity of the hemodynamic response function (HRF) is determined spatially by the vascular architecture and temporally by the evolution of hemodynamic changes. Here, we used functional photoacoustic microscopy (fPAM) to investigate single cerebral blood vessels of rats after left forepaw stimulation. In this system, we analyzed the spatiotemporal evolution of the HRFs of the total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2). Changes in specific cerebral vessels corresponding to various electrical stimulation intensities and durations were bilaterally imaged with 36×65-?m2 spatial resolution. Stimulation intensities of 1, 2, 6, and 10 mA were applied for periods of 5 or 15 s. Our results show that the relative functional changes in HbT, CBV, and SO2 are highly dependent not only on the intensity of the stimulation, but also on its duration. Additionally, the duration of the stimulation has a strong influence on the spatiotemporal characteristics of the HRF as shorter stimuli elicit responses only in the local vasculature (smaller arterioles), whereas longer stimuli lead to greater vascular supply and drainage. This study suggests that the current fPAM system is reliable for studying relative cerebral hemodynamic changes, as well as for offering new insights into the dynamics of functional cerebral hemodynamic changes in small animals.

Liao, Lun-De; Lin, Chin-Teng; Shih, Yen-Yu I.; Lai, Hsin-Yi; Zhao, Wan-Ting; Duong, Timothy Q.; Chang, Jyh-Yeong; Chen, You-Yin; Li, Meng-Lin

2012-06-01

289

Blood flow in a compliant vessel by the immersed boundary method.  

PubMed

In this paper we develop a computational approach to analyze hemodynamics in the aorta; this may serve as a useful tool in the development of noninvasive methods to detect early onset of diseases such as aneurysms and stenosis in major blood vessels. We introduce a mathematical model which describes the interaction of blood flow with the aortic wall; this model is based on the immersed boundary method. A two-dimensional vessel model is constructed, the velocity at the inlet is prescribed based on the information from the Magnetic Resonance Imaging data measured in the aorta of a healthy subject, and the velocity at the outlet is prescribed by driving the pressure level reproduced from the literature. The mathematical model is validated by comparing with well-known solutions of the viscous incompressible Navier-Stokes equations, i.e., Womersley flow. The hysteresis behavior in the pressure-diameter relation is observed when the viscoelastic material property of the arterial wall is taken into consideration. Five different shapes of aortic wall are considered for comparison of the flow patterns inside the aorta: one for the normal aorta, two for the dilated aorta, and two for the constrictive aorta. PMID:19283479

Kim, Yongsam; Lim, Sookkyung; Raman, Subha V; Simonetti, Orlando P; Friedman, Avner

2009-03-13

290

Stress-strain measurements and viscoelastic response of blood vessels cryopreserved by vitrification.  

PubMed

To gain increased insight into thermo-mechanical phenomena during cryopreservation, tensile stress relaxation experiments were conducted on vitrified blood vessels (vitreous in Latin means Glassy), and the results compared with various viscoelastic models. Using a recently presented device, isothermal stress-relaxation results were obtained for a bovine carotid artery model, permeated with the cryoprotectant cocktail VS55 and a reference solution of 7.05 M DMSO. After a rapidly applied tensile strain, experimental results display exponential decay of stress with time; the stress at a given time increases with decreasing specimen temperature. Among the viscoelastic models investigated, the Williams-Landel-Ferry model was found to best-fit the variation of the stress relaxation data with temperature, while a Maxwell-Weichert model is used to represent the exponential decay of the stress with time. Blood vessel properties were found to dominate at temperatures above roughly -100 degrees C, while the properties of the cryoprotectant dominate below this temperature. A suitably defined steady-state viscosity displayed a similar behavior for both cryoprotectants, when normalized with respect to the cryoprotectant glass transition temperature. PMID:17828592

Jimenez Rios, Jorge L; Steif, Paul S; Rabin, Yoed

2007-09-09

291

Interaction of a dual-wavelength laser system with cutaneous blood vessels  

NASA Astrophysics Data System (ADS)

Our working hypothesis is that a dual-wavelength Nd:YAG laser, emitting simultaneously at 1064 and 532 nm, may induce stronger heating of PWS blood vessels relative to the epidermis than the customary KTP laser, due to conversion of hemoglobin to met-hemoglobin in the target blood vessels and the associated increase in NIR absorption. We apply pulsed photothermal radiometry to determine temperature depth profiles induced in PWS lesions by a dual-wavelength laser at sub-therapeutic radiant exposures. The results indicate no effect at 1 ms pulse duration and low radiant exposures (1-2 J/cm2). Increased radiant exposure (3-4 J/cm2) and extended pulse duration (20-25 ms) result in increased energy deposition. In addition, two PWS lesions and one healthy skin site were irradiated at incrementally increasing radiant exposures, up to 9 J/cm2. Analysis of the laser-induced temperature profiles clearly revealed irreversible changes of tissue properties. Formation of met-hemoglobin and consequent increase of IR absorption was however not reliably detected.

Majaron, Boris; Milani?, Matija; Nelson, J. S.

2007-06-01

292

Infrared Free Electron Laser Induced Angioplasty for Arteriosclerotic Region of Blood Vessels  

NASA Astrophysics Data System (ADS)

In order to estimate the optimum laser conditions for efficient dissociation of cholesterol ester in an arteriosclerotic region of blood vessels, we have investigated the relationship between laser wavelength and power density on cholesterol ester dissociation using a mid infrared free electron laser (MIR-FEL). In this study, cholesteryl oleate, which is a typical cholesterol ester found in arteriosclerotic regions, was irradiated with 5.75-?m-FELs, which cause vibration of ester bonds. Two results were obtained. (1) Ester dissociated depending on the absorption coefficient, and the macropulse duration was shorter than the thermal relaxation time, showing that ester bonds dissociated into carboxylic acid and cholesterol by macropulse-induced thermal effects without accompanying thermal diffusion, (2) Using a wavelength of 5.75 ?m, the maximum ester dissociation ratio was achieved under the optimum laser conditions of a macropulse energy density of 0.4-1.0 J/cm2. We conclude that MIR pulsed-lasers with a wavelength of 5.75 ?m can be useful for removal of cholesteryl ester in an arteriosclerotic region of blood vessels.

Awazu, Kunio; Fukami, Yuko

2004-08-01

293

Three-dimensional reconstruction of blood vessels extracted from retinal fundus images.  

PubMed

We present a 3D reconstruction of retinal blood vessel trees using two views of fundus images. The problem is addressed by using well known computer vision techniques which consider: 1) The recovery of camera-eyeball model parameters by an auto-calibration method. The camera parameters are found via the solution of simplified Kruppa equations, based on correspondences found by a LMedS optimisation correlation between pairs of eight different views. 2) The extraction of blood vessels and skeletons from two fundus images. 3) The matching of corresponding points of the two skeleton trees. The trees are previously labelled during the analysis of 2D binary images. Finally, 4) the lineal triangulation of matched correspondence points and the surface modelling via generalised cylinders using diameter measurements extracted from the 2D binary images. The method is nearly automatic and it is tested with 2 sets of 10 fundus retinal images, each one taken from different subjects. Results of 3D vein and artery trees reconstructions are shown. PMID:22565765

Martinez-Perez, M Elena; Espinosa-Romero, Arturo

2012-05-01

294

Investigation of the cerebral hemodynamic response function in single blood vessels by functional photoacoustic microscopy.  

PubMed

The specificity of the hemodynamic response function (HRF) is determined spatially by the vascular architecture and temporally by the evolution of hemodynamic changes. Here, we used functional photoacoustic microscopy (fPAM) to investigate single cerebral blood vessels of rats after left forepaw stimulation. In this system, we analyzed the spatiotemporal evolution of the HRFs of the total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO(2)). Changes in specific cerebral vessels corresponding to various electrical stimulation intensities and durations were bilaterally imaged with 36 × 65-?m(2) spatial resolution. Stimulation intensities of 1, 2, 6, and 10 mA were applied for periods of 5 or 15 s. Our results show that the relative functional changes in HbT, CBV, and SO(2) are highly dependent not only on the intensity of the stimulation, but also on its duration. Additionally, the duration of the stimulation has a strong influence on the spatiotemporal characteristics of the HRF as shorter stimuli elicit responses only in the local vasculature (smaller arterioles), whereas longer stimuli lead to greater vascular supply and drainage. This study suggests that the current fPAM system is reliable for studying relative cerebral hemodynamic changes, as well as for offering new insights into the dynamics of functional cerebral hemodynamic changes in small animals. PMID:22734740

Liao, Lun-De; Lin, Chin-Teng; Shih, Yen-Yu I; Lai, Hsin-Yi; Zhao, Wan-Ting; Duong, Timothy Q; Chang, Jyh-Yeong; Chen, You-Yin; Li, Meng-Lin

2012-06-01

295

Ultrasound sonication with microbubbles disrupts blood vessels and enhances tumor treatments of anticancer nanodrug  

PubMed Central

Ultrasound (US) sonication with microbubbles (MBs) has the potential to disrupt blood vessels and enhance the delivery of drugs into the sonicated tissues. In this study, mouse ear tumors were employed to investigate the therapeutic effects of US, MBs, and pegylated liposomal doxorubicin (PLD) on tumors. Tumors started to receive treatments when they grew up to about 15 mm3 (early stage) with injection of PLD 10 mg/kg, or up to 50 mm3 (medium stage) with PLD 6 (or 4) mg/kg. Experiments included the control, PLD alone, PLD + MBs + US, US alone, and MBs + US groups. The procedure for the PLD + MBs + US group was that PLD was injected first, MB (SonoVue) injection followed, and then US was immediately sonicated on the tumor. The results showed that: (1) US sonication with MBs was always able to produce a further hindrance to tumor growth for both early and medium-stage tumors; (2) for the medium-stage tumors, 6 mg/kg PLD alone was able to inhibit their growth, while it did not work for 4 mg/kg PLD alone; (3) with the application of MBs + US, 4 mg/kg PLD was able to inhibit the growth of medium-stage tumors; (4) for early stage tumors after the first treatment with a high dose of PLD alone (10 mg/kg), the tumor size still increased for several days and then decreased (a biphasic pattern); (5) MBs + US alone was able to hinder the growth of early stage tumors, but unable to hinder that of medium stage tumors. The results of histological examinations and blood perfusion measurements indicated that the application of MBs + US disrupts the tumor blood vessels and enhances the delivery of PLD into tumors to significantly inhibit tumor growth.

Lin, Chung-Yin; Tseng, Hsiao-Ching; Shiu, Heng-Ruei; Wu, Ming-Fang; Chou, Cheng-Ying; Lin, Win-Li

2012-01-01

296

Label-free 3D imaging of microstructure, blood, and lymphatic vessels within tissue beds in vivo.  

PubMed

This Letter reports the use of an ultrahigh resolution optical microangiography (OMAG) system for simultaneous 3D imaging of microstructure and lymphatic and blood vessels without the use of an exogenous contrast agent. An automatic algorithm is developed to segment the lymphatic vessels from the microstructural images based on the fact that the lymph fluid is optically transparent. An OMAG system is developed that utilizes a broadband supercontinuum light source, providing an axial resolution of 2.3 ?m and lateral resolution of 5.8 ?m, capable of resolving the capillary vasculature and lymphatic vessels innervating microcirculatory tissue beds. Experimental demonstration is performed by showing detailed 3D lymphatic and blood vessel maps, coupled with morphology, within mouse ears in vivo. PMID:22378402

Zhi, Zhongwei; Jung, Yeongri; Wang, Ruikang K

2012-03-01

297

Laser Doppler measurements of inner ear blood flow during experimental thrombosis of cochlear blood vessels in the guinea pig.  

PubMed

This study investigated the vascular effect of ferromagnetic obstruction of cochlear blood vessels in the guinea pig using dual-channel laser Doppler flowmetry. To improve this technique, we tested new types of magnets and iron spheres. In so doing, the cochlear temperature was lowered selectively and general hypothermia was avoided. The success of vascular impairment in the inner ear was found to depend on the experimental conditions used. Given normothermic conditions (38 degrees C body temperature), a clear reduction in cochlear blood flow (CBF) was found in only about 30% of the animals tested when an aluminium-nickel-cobalt alloy magnet and carbonyl iron spheres were used, while this ratio increased to about 80% under general hypothermia (33 degrees C). Using a stronger neodymium-iron-boron magnet and smaller-sized iron spheres, we found the success of vascular obstruction to be approximately 70% under normothermia and 100% with local hypothermia (to 33 degrees C) of the cochlea. Although the extent of vascular impairment revealed a considerable interindividual variation, the present findings demonstrate that ferromagnetic intervention in CBF with dual-channel laser Doppler flowmetry can be used to investigate the effect of quantified cochlear ischemia on inner ear physiology in the guinea pig model and test various therapeutic strategies. PMID:9065662

Scheibe, F; Haupt, H; Grunert, H

1997-01-01

298

Low level arsenic promotes progressive inflammatory angiogenesis and liver blood vessel remodeling in mice  

SciTech Connect

The vascular effects of arsenic in drinking water are global health concerns contributing to human disease worldwide. Arsenic targets the endothelial cells lining blood vessels, and endothelial cell activation or dysfunction may underlie the pathogenesis of both arsenic-induced vascular diseases and arsenic-enhanced tumorigenesis. The purpose of the current studies was to demonstrate that exposing mice to drinking water containing environmentally relevant levels of arsenic promoted endothelial cell dysfunction and pathologic vascular remodeling. Increased angiogenesis, neovascularization, and inflammatory cell infiltration were observed in Matrigel plugs implanted in C57BL/6 mice following 5-week exposures to 5-500 ppb arsenic [Soucy, N.V., Mayka, D., Klei, L.R., Nemec, A.A., Bauer, J.A., Barchowsky, A., 2005. Neovascularization and angiogenic gene expression following chronic arsenic exposure in mice. Cardiovasc.Toxicol 5, 29-42]. Therefore, functional in vivo effects of arsenic on endothelial cell function and vessel remodeling in an endogenous vascular bed were investigated in the liver. Liver sinusoidal endothelial cells (LSEC) became progressively defenestrated and underwent capillarization to decrease vessel porosity following exposure to 250 ppb arsenic for 2 weeks. Sinusoidal expression of PECAM-1 and laminin-1 proteins, a hallmark of capillarization, was also increased by 2 weeks of exposure. LSEC caveolin-1 protein and caveolae expression were induced after 2 weeks of exposure indicating a compensatory change. Likewise, CD45/CD68-positive inflammatory cells did not accumulate in the livers until after LSEC porosity was decreased, indicating that inflammation is a consequence and not a cause of the arsenic-induced LSEC phenotype. The data demonstrate that the liver vasculature is an early target of pathogenic arsenic effects and that the mouse liver vasculature is a sensitive model for investigating vascular health effects of arsenic.

Straub, Adam C. [Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, PA 15219 (United States); Stolz, Donna B. [Department of Cell Biology, University of Pittsburgh School of Medicine, PA 15219 (United States); Vin, Harina [Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, PA 15219 (United States); Department of Cell Biology, University of Pittsburgh School of Medicine, PA 15219 (United States); Ross, Mark A. [Department of Cell Biology, University of Pittsburgh School of Medicine, PA 15219 (United States); Soucy, Nicole V. [Department of Pharmacology and Toxicology, Dartmouth Medical School (United States); Klei, Linda R. [Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, PA 15219 (United States); Barchowsky, Aaron [Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, PA 15219 (United States)], E-mail: aab20@pitt.edu

2007-08-01

299

Biaxial biomechanical properties of self-assembly tissue-engineered blood vessels  

PubMed Central

Along with insights into the potential for graft success, knowledge of biomechanical properties of small diameter tissue-engineered blood vessel (TEBV) will enable designers to tailor the vessels' mechanical response to closer resemble that of native tissue. Composed of two layers that closely mimic the native media and adventitia, a tissue-engineered vascular adventitia (TEVA) is wrapped around a tissue-engineered vascular media (TEVM) to produce a self-assembled tissue-engineered media/adventia (TEVMA). The current study was undertaken to characterize the biaxial biomechanical properties of TEVM, TEVA and TEVMA under physiological pressures as well as characterize the stress-free reference configuration. It was shown that the TEVA had the greatest compliance over the physiological loading range while the TEVM had the lowest compliance. As expected, compliance of the SA-TEBV fell in between with an average compliance of 2.73 MPa?1. Data were used to identify material parameters for a microstructurally motivated constitutive model. Identified material parameters for the TEVA and TEVM provided a good fit to experimental data with an average coefficient of determination of 0.918 and 0.868, respectively. These material parameters were used to develop a two-layer predictive model for the response of a TEVMA which fit well with experimental data.

Zaucha, Michael T.; Gauvin, Robert; Auger, Francois A.; Germain, Lucie; Gleason, Rudolph L.

2011-01-01

300

Linear and branched perfluorooctane sulfonate (PFOS) isomer patterns differ among several tissues and blood of polar bears.  

PubMed

Perfluorooctane sulfonate (PFOS) is a globally distributed persistent organic pollutant that has been found to bioaccumulate and biomagnify in aquatic food webs. Although principally in its linear isomeric configuration, 21-35% of the PFOS manufactured via electrochemical fluorination is produced as a branched structural isomer. PFOS isomer patterns were investigated in multiple tissues of polar bears (Ursus maritimus) from East Greenland. The liver (n=9), blood (n=19), brain (n=16), muscle (n=5), and adipose (n=5) were analyzed for linear PFOS (n-PFOS), as well as multiple mono- and di-trifluoromethyl-substituted branched isomers. n-PFOS accounted for 93.0±0.5% of ?-PFOS isomer concentrations in the liver, whereas the proportion was significantly lower (p<0.05) in the blood (85.4±0.5%). Branched isomers were quantifiable in the liver and blood, but not in the brain, muscle, or adipose. In both the liver and blood, 6-perfluoromethylheptane sulfonate (P6MHpS) was the dominant branched isomer (2.61±0.10%, and 3.26±0.13% of ?-PFOS concentrations, respectively). No di-trifluoromethyl-substituted isomers were detectable in any of the tissues analyzed. These tissue-specific isomer patterns suggest isomer-specific pharmacokinetics, perhaps due to differences in protein affinities, and thus differences in protein interactions, as well transport, absorption, and/or metabolism in the body. PMID:23920361

Greaves, Alana K; Letcher, Robert J

2013-08-03

301

Transgenic chimera quail production by microinjecting lentiviral vector into the blood vessel of the early embryo.  

PubMed

In the past, several strategies have been used to generate transgenic birds. The most successful method has proven to be injection of lentiviral vector into the subgerminal cavity of the newly laid egg. In this study, we directly injected lentiviral vector into the blood vessel of HH13-15 quail embryos to produce transgenic chimeras. In the manipulated, hatched birds, the green fluorescent protein (GFP) gene driven by a cytomegalovirus (CMV) promoter was extensively expressed. All tissues analyzed were GFP-positive, and gonad cells from some of the manipulated embryos expressed GFP. The semen genome of 21.4% of mature male birds was determined to be GFP-positive by PCR, indicating these male birds were transgenic chimeras. PMID:22515688

Sun, Peng; Zhang, Zifu; Wu, Guojin; Yan, Li; Yuan, Fang; Zhang, Wenxin; Gao, Junshuang; Jin, Wenjing; Li, Zandong

2011-12-08

302

Accurate tracking of blood vessels and EEG electrodes by consecutive cross-section matching  

NASA Astrophysics Data System (ADS)

We discuss the quality by which image algorithms are able to characterize 3D line structure, like blood vessels, nerves, chromosomes, electrodes, etc. In the study, the methods are examined how well they can determine the axial position, local intensity, local diameter, or local orientation under conditions of noise, bifurcations and neighbor structures. We present the Consecutive Cross-Section Matching (CCSM) method, and compare it with the global method of Lorentz and the local slice method of Zhou. When applying the methods on a circular test image and 3D phase-contrast MR angiography image, we find that the Lorentz method gives reasonable estimates for the width of the line-structures, but has large difficulties to pass bifurcations. The local slice method is more accurate but is sensitive to noise. As the CCSM method takes more samples along the axis, the CCSM method appears to be much more accurate and robust in characterizing line-structures.

Noordmans, Herke J.; Smeulders, Arnold W.; Viergever, Max A.

1999-05-01

303

Genetic algorithm matched filter optimization for automated detection of blood vessels from digital retinal images.  

PubMed

Due to the importance of the matched filter in the automated detection of blood vessels in digital retinal images, improving its response is highly desirable. This filter may vary in many ways depending on the parameters that govern its response. In this paper, new parameters to optimize the sensitivity of the matched filter are found using genetic algorithms on the test set of the DRIVE databases. The area under the receiver operating curve (ROC) is used as a fitness function for the genetic algorithm. To evaluate the improved matched filter, the maximum average accuracy (MAA) is calculated to be 0.9422 and the average area under ROC is 0.9582. PMID:17610985

Al-Rawi, Mohammed; Karajeh, Huda

2007-07-03

304

Resonant Doppler flow imaging and optical vivisection of retinal blood vessels  

NASA Astrophysics Data System (ADS)

For Fourier domain optical coherence tomography any sample movement during camera integration causes blurring of interference fringes and as such reduction of sensitivity for flow detection. The proposed method overcomes this problem by phase-matching a reference signal to the sample motion. The interference fringes corresponding to flow signal will appear frozen across the detector whereas those of static sample structures will be blurred resulting in enhanced contrast for blood vessels. An electro-optic phase modulator in the reference arm, driven with specific phase cycles locked to the detection frequency, allows not only for qualitative but also for quantitative flow detection already from the relative signal intensities. First applications to extract in-vivo retinal flow and to visualize 3D vascularization, i.e. optical vivisection, are presented.

Bachmann, Adrian H.; Villiger, Martin L.; Blatter, Cedric; Lasser, Theo; Leitgeb, Rainer A.

2007-01-01

305

Resonant Doppler flow imaging and optical vivisection of retinal blood vessels.  

PubMed

For Fourier domain optical coherence tomography any sample movement during camera integration causes blurring of interference fringes and as such reduction of sensitivity for flow detection. The proposed method overcomes this problem by phase-matching a reference signal to the sample motion. The interference fringes corresponding to flow signal will appear frozen across the detector whereas those of static sample structures will be blurred resulting in enhanced contrast for blood vessels. An electro-optic phase modulator in the reference arm, driven with specific phase cycles locked to the detection frequency, allows not only for qualitative but also for quantitative flow detection already from the relative signal intensities. First applications to extract in-vivo retinal flow and to visualize 3D vascularization, i.e. optical vivisection, are presented. PMID:19532258

Bachmann, Adrian H; Villiger, Martin L; Blatter, Cedric; Lasser, Theo; Leitgeb, Rainer A

2007-01-22

306

Cancer cells that survive radiation therapy acquire HIF-1 activity and translocate towards tumour blood vessels  

PubMed Central

Tumour recurrence frequently occurs after radiotherapy, but the characteristics, intratumoural localization and post-irradiation behaviour of radioresistant cancer cells remain largely unknown. Here we develop a sophisticated strategy to track the post-irradiation fate of the cells, which exist in perinecrotic regions at the time of radiation. Although the perinecrotic tumour cells are originally hypoxia-inducible factor 1 (HIF-1)-negative, they acquire HIF-1 activity after surviving radiation, which triggers their translocation towards tumour blood vessels. HIF-1 inhibitors suppress the translocation and decrease the incidence of post-irradiation tumour recurrence. For the first time, our data unveil the HIF-1-dependent cellular dynamics during post-irradiation tumour recurrence and provide a rational basis for targeting HIF-1 after radiation therapy.

Harada, Hiroshi; Inoue, Masahiro; Itasaka, Satoshi; Hirota, Kiichi; Morinibu, Akiyo; Shinomiya, Kazumi; Zeng, Lihua; Ou, Guangfei; Zhu, Yuxi; Yoshimura, Michio; McKenna, W. Gillies; Muschel, Ruth J.; Hiraoka, Masahiro

2012-01-01

307

The mathematical formulation of a generalized Hooke's law for blood vessels.  

PubMed

It is well known that the stress-strain relationship of blood vessels is highly nonlinear. To linearize the relationship, the Hencky strain tensor is generalized to a logarithmic-exponential (log-exp) strain tensor to absorb the nonlinearity. A quadratic nominal strain potential is proposed to derive the second Piola-Kirchhoff stresses by differentiating the potential with respect to the log-exp strains. The resulting constitutive equation is a generalized Hooke's law. Ten material constants are needed for the three-dimensional orthotropic model. The nondimensional constant used in the log-exp strain definition is interpreted as a nonlinearity parameter. The other nine constants are the elastic moduli with respect to the log-exp strains. In this paper, the proposed linear stress-strain relation is shown to represent the pseudoelastic Fung model very well. PMID:17512049

Zhang, Wei; Wang, Chong; Kassab, Ghassan S

2007-05-03

308

[Organization of emergency aid to persons with injuries of the major blood vessels].  

PubMed

Emergency aid given to 1,258 persons with injury to the blood vessels is analysed. A new classification and 4 independent stages of emergency service are distinguished. An attempt is made to find common principles of organization of aid in time of peace and in time of war. The tactics in a combined vascular-nerve injury are substantiated, the indications for a tourniquet (18.3%) and temporary prostheses (16.9%) are suggested for reducing the incidence of postoperative complications, amputations, and mortality. The results of treatment (%): amputations, at the place of the accident 6.2, in the center 4.4, mortality 9.6 and 2.2, respectively. The percentage of purulent complications was similar--6.6. PMID:7630085

Makarova, N P; Ermolaev, V L

1995-01-01

309

Automatic segmentation of pulmonary blood vessels and nodules based on local intensity structure analysis and surface propagation in 3D chest CT images  

Microsoft Academic Search

Purpose  Pulmonary nodules may indicate the early stage of lung cancer, and the progress of lung cancer causes associated changes in\\u000a the shape and number of pulmonary blood vessels. The automatic segmentation of pulmonary nodules and blood vessels is desirable\\u000a for chest computer-aided diagnosis (CAD) systems. Since pulmonary nodules and blood vessels are often attached to each other,\\u000a conventional nodule detection

Bin Chen; Takayuki Kitasaka; Hirotoshi Honma; Hirotsugu Takabatake; Masaki Mori; Hiroshi Natori; Kensaku Mori

310

Transgenic Quail Production by Microinjection of Lentiviral Vector into the Early Embryo Blood Vessels  

PubMed Central

Several strategies have been used to generate transgenic birds. The most successful method so far has been the injection of lentiviral vectors into the subgerminal cavity of a newly laid egg. We report here a new, easy and effective way to produce transgenic quails through direct injection of a lentiviral vector, containing an enhanced-green fluorescent protein (eGFP) transgene, into the blood vessels of quail embryos at Hamburger-Hamilton stage 13–15 (HH13–15). A total of 80 embryos were injected and 48 G0 chimeras (60%) were hatched. Most injected embryo organs and tissues of hatched quails were positive for eGFP. In five out of 21 mature G0 male quails, the semen was eGFP-positive, as detected by polymerase chain reaction (PCR), indicating transgenic germ line chimeras. Testcross and genetic analyses revealed that the G0 quail produced transgenic G1 offspring; of 46 G1 hatchlings, 6 were transgenic (6/46, 13.0%). We also compared this new method with the conventional transgenesis using stage X subgerminal cavity injection. Total 240 quail embryos were injected by subgerminal cavity injection, of which 34 (14.1%) were hatched, significantly lower than the new method. From these hatched quails semen samples were collected from 19 sexually matured males and tested for the transgene by PCR. The transgene was present in three G0 male quails and only 4/236 G1 offspring (1.7%) were transgenic. In conclusion, we developed a novel bird transgenic method by injection of lentiviral vector into embryonic blood vessel at HH 13–15 stage, which result in significant higher transgenic efficiency than the conventional subgerminal cavity injection.

Zhang, Zifu; Sun, Peng; Yu, Fuxian; Yan, Li; Yuan, Fang; Zhang, Wenxin; Wang, Tao; Wan, Zhiyi; Shao, Qiang; Li, Zandong

2012-01-01

311

Blood vessel-based liver segmentation through the portal phase of a CT dataset  

NASA Astrophysics Data System (ADS)

Blood vessels are dispersed throughout the human body organs and carry unique information for each person. This information can be used to delineate organ boundaries. The proposed method relies on abdominal blood vessels (ABV) to segment the liver considering the potential presence of tumors through the portal phase of a CT dataset. ABV are extracted and classified into hepatic (HBV) and nonhepatic (non-HBV) with a small number of interactions. HBV and non-HBV are used to guide an automatic segmentation of the liver. HBV are used to individually segment the core region of the liver. This region and non-HBV are used to construct a boundary surface between the liver and other organs to separate them. The core region is classified based on extracted posterior distributions of its histogram into low intensity tumor (LIT) and non-LIT core regions. Non-LIT case includes normal part of liver, HBV, and high intensity tumors if exist. Each core region is extended based on its corresponding posterior distribution. Extension is completed when it reaches either a variation in intensity or the constructed boundary surface. The method was applied to 80 datasets (30 Medical Image Computing and Computer Assisted Intervention (MICCAI) and 50 non-MICCAI data) including 60 datasets with tumors. Our results for the MICCAI-test data were evaluated by sliver07 [1] with an overall score of 79.7, which ranks seventh best on the site (December 2013). This approach seems a promising method for extraction of liver volumetry of various shapes and sizes and low intensity hepatic tumors.

Maklad, Ahmed S.; Matsuhiro, Mikio; Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Moriyama, Noriyuki; Utsunomiya, Toru; Shimada, Mitsuo

2013-02-01

312

Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels.  

PubMed

German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (-)-?-bisabolol, farnesene, umbelliferone; 3-30?M) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (-)-?-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (-)-?-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by l-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30?M, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (-)-?-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. PMID:23845591

Roberts, R E; Allen, S; Chang, A P Y; Henderson, H; Hobson, G C; Karania, B; Morgan, K N; Pek, A S Y; Raghvani, K; Shee, C Y; Shikotra, J; Street, E; Abbas, Z; Ellis, K; Heer, J K; Alexander, S P H

2013-07-08

313

Degradation profile and preliminary clinical testing of a resorbable device for ligation of blood vessels.  

PubMed

A resorbable device for ligation of blood vessels was developed and tested in vitro to reveal the degradation profile of the device and to predict the clinical performance in terms of adequate mechanical support during a healing period of 1week. In addition, preliminary clinical testing was performed that showed complete hemostasis and good tissue grip of renal arteries in five pigs. The device was made by injection molding of poly(glycolide-co-trimethylene carbonate) triblock copolymer, and it consisted of a case with a locking mechanism connected to a partly perforated flexible band. A hydrolytic degradation study was carried out for 7, 30 and 60days in water and buffer medium, following the changes in mass, water absorption, pH and mechanical properties. A new rapid matrix-free laser desorption ionization-mass spectrometry (LDI-MS) method was developed for direct screening of degradation products released into the degradation medium. The combination of LDI-MS and electrospray ionization-mass spectrometry analyses enabled the comparison of the degradation product patterns in water and buffer medium. The identified degradation products were rich in trimethylene carbonate units, indicating preferential hydrolysis of amorphous regions where trimethylene units are located. The crystallinity of the material was doubled after 60days of hydrolysis, additionally confirming the preferential hydrolysis of trimethylene carbonate units and the enrichment of glycolide units in the remaining solid matrix. The mechanical performance of the perforated band was followed for the first week of hydrolysis and the results suggest that sufficient strength is retained during the healing time of the blood vessels. PMID:23438863

Aminlashgari, Nina; Höglund, Odd V; Borg, Niklas; Hakkarainen, Minna

2013-02-21

314

BLOOD VESSELS IN FAT TISSUE. RELATION TO PROBLEMS OF GAS EXCHANGE  

PubMed Central

1. The ratio of the surface of the capillary bed to the volume of tissue supplied by the vessels (S/V ratio) for both open and closed capillaries in fat-rich tissue of the rat is 51.9, in fat-poor tissue of the same sort 222.2. About one-half of the capillaries in fat-rich tissue, to one-fourth in fat-poor tissue, are open during ordinary activity. The total capillary bed of fat-rich tissue is one-third as great as in muscle; the total capillary bed of fat-poor tissue has about the same density as that of the most poorly supplied muscle. This establishes the fact quantitatively that the capillary bed of fat is relatively inadequate, compared to other tissues, for transferring inert gases from fat tissue at a sufficiently rapid rate to prevent the occurrence of extravascular bubbles following rapid decompression from high pressure atmospheres. It also explains the greater distention of the blood vessels in fat tissue, due to gas, than in any other tissue following decompression. The observations have a bearing also on the estimation of the permeability of the blood-fat barrier to inert gases. 2. The volume of protoplasm of fat cells may be very small; a method is presented for estimating it quantitatively. Since it alone is important in metabolism, recalculation of the basic data on a basis of the ratio of surface area of capillaries to volume of protoplasm of fat cell in fat tissue yields a more useful figure. For fat-rich fat tissue S/V (protoplasm) = 2159.0 (for total capillary surface) or 977.6 (for open capillary surface). This means that for purpose of metabolism, the capillary bed is far richer than that of muscle.

Gersh, Isidore; Still, Mary A.

1945-01-01

315

In vivo nanomechanical imaging of blood-vessel tissues directly in living mammals using atomic force microscopy  

NASA Astrophysics Data System (ADS)

Atomic force microscopy (AFM) is difficult to achieve in living mammals but is necessary for understanding mechanical properties of tissues in their native form in organisms. Here we report in vivo nanomechanical imaging of blood-vessel tissues directly in living mammalians by AFM combined with surgical operations. Nanomechanical heterogeneity of blood vessels is observed across the diverse microenvironments of the same tissues in vivo. This method is further used to measure the counteractive nanomechanical changes in real time during drug-induced vasodilation and vasoconstriction in vivo, demonstrating appealing potential in characterization of in vivo nanomechanical dynamics of native tissues.

Mao, Youdong; Sun, Quanmei; Wang, Xiufeng; Ouyang, Qi; Han, Li; Jiang, Lei; Han, Dong

2009-07-01

316

Anatomical consideration of the radial artery for transradial coronary procedures: arterial diameter, branching anomaly and vessel tortuosity  

Microsoft Academic Search

BackgroundThe radial artery is currently regarded as a useful vascular access site for coronary procedures. Adequate anatomical information of the radial artery should be helpful in performing the transradial coronary procedure. Therefore, we tried to evaluate the size of radial artery, the incidence and clinical significance of anomalous branching patterns and tortuosity of the radial artery related with transradial coronary

Byung-Su Yoo; Junghan Yoon; Ji-Yean Ko; Jang-Young Kim; Seung-Hwan Lee; Sung-Oh Hwang; Kyung-Hoon Choe

2005-01-01

317

The Behaviors of Ferro-Magnetic Nano-Particles In and Around Blood Vessels under Applied Magnetic Fields  

PubMed Central

In magnetic drug delivery, therapeutic magnetizable particles are typically injected into the blood stream and magnets are then used to concentrate them to disease locations. The behavior of such particles in-vivo is complex and is governed by blood convection, diffusion (in blood and in tissue), extravasation, and the applied magnetic fields. Using physical first-principles and a sophisticated vessel-membrane-tissue (VMT) numerical solver, we comprehensively analyze in detail the behavior of magnetic particles in blood vessels and surrounding tissue. For any blood vessel (of any size, depth, and blood velocity) and tissue properties, particle size and applied magnetic fields, we consider a Krogh tissue cylinder geometry and solve for the resulting spatial distribution of particles. We find that there are three prototypical behaviors (blood velocity dominated, magnetic force dominated, and boundary-layer formation) and that the type of behavior observed is uniquely determined by three non-dimensional numbers (the magnetic-Richardson number, mass Péclet number, and Renkin reduced diffusion coefficient). Plots and equations are provided to easily read out which behavior is found under which circumstances (Figures 5, 6, 7, and 8). We compare our results to previously published in-vitro and in-vivo magnetic drug delivery experiments. Not only do we find excellent agreement between our predictions and prior experimental observations, but we are also able to qualitatively and quantitatively explain behavior that was previously not understood.

Nacev, A.; Beni, C.; Bruno, O.; Shapiro, B.

2010-01-01

318

Biogenic amines modulate pulse rate in the dorsal blood vessel of Lumbriculus variegatus.  

PubMed

The biogenic amines are widespread regulators of physiological processes, and play an important role in regulating heart rate in diverse organisms. Here, we present the first pharmacological evidence for a role of the biogenic amines in the regulation of dorsal blood vessel pulse rate in an aquatic oligochaete, Lumbriculus variegatus (Müller, 1774). Bath application of octopamine to intact worms resulted in an acceleration of pulse rate, but not when co-applied with the adenylyl cyclase inhibitor MDL-12,330a. The phosphodiesterase inhibitor theophylline mimicked the effects of OA, but the polar adenosine receptor antagonist 8(p-sulphophenyl)theophylline was significantly less potent than theophylline. Pharmacologically blocking synaptic reuptake of the biogenic amines using the selective 5-HT reuptake blocker fluoxetine or various tricyclic antidepressants also accelerated heart rate. Depletion of the biogenic amines by treatment with the monoamine vesicular transporter blocker reserpine dramatically depressed pulse rate. Pulse rate was partially restored in amine-depleted worms after treatment with octopamine or dopamine, but fully restored following treatment with serotonin. This effect of 5-HT was weakly mimicked by 5-methoxytryptamine, but not by alpha-methylserotonin; it was completely blocked by clozapine and partially blocked by cyproheptadine. Because they are known to orchestrate a variety of adaptive behaviors in invertebrates, the biogenic amines may coordinate blood flow with behavioral state in L.variegatus. PMID:20167287

Crisp, Kevin M; Grupe, Rebecca E; Lobsang, Tenzin T; Yang, Xong

2010-02-16

319

Blood vessel maturation in a 3-dimensional spheroidal coculture model: direct contact with smooth muscle cells regulates endothelial cell quiescence and abrogates VEGF responsiveness  

Microsoft Academic Search

Paracrine interactions between endothe- lial cells (EC) and mural cells act as critical regulators of vessel wall assembly, vessel maturation and define a plasticity window for vascular remodeling. The present study was aimed at studying blood vessel maturation processes in a novel 3-dimensional spheroidal coculture system of EC and smooth muscle cells (SMC). Cocul- ture spheroids differentiate spontaneously in a

THOMAS KORFF; SARAH KIMMINA; GEORG MARTINY-BARON; HELLMUT G. AUGUSTIN

2001-01-01

320

Retinal image analysis aimed at blood vessel tree segmentation and early detection of neural-layer deterioration.  

PubMed

An automatic method of segmenting the retinal vessel tree and estimating status of retinal neural fibre layer (NFL) from high resolution fundus camera images is presented. First, reliable blood vessel segmentation, using 2D directional matched filtering, enables to remove areas occluded by blood vessels thus leaving remaining retinal area available to the following NFL detection. The local existence of rather faint and hardly visible NFL is detected by combining several newly designed local textural features, sensitive to subtle NFL characteristics, into feature vectors submitted to a trained neural-network classifier. Obtained binary retinal maps of NFL distribution show a good agreement with both medical expert evaluations and quantitative results obtained by optical coherence tomography. PMID:22640597

Jan, J; Odstrcilik, J; Gazarek, J; Kolar, R

2012-05-27

321

Forces on a Wall-Bound Leukocyte in a Small Vessel Due to Red Cells in the Blood Stream  

PubMed Central

As part of the inflammation response, white blood cells (leukocytes) are well known to bind nearly statically to the vessel walls, where they must resist the force exerted by the flowing blood. This force is particularly difficult to estimate due to the particulate character of blood, especially in small vessels where the red blood cells must substantially deform to pass an adhered leukocyte. An efficient simulation tool with realistically flexible red blood cells is used to estimate these forces. At these length scales, it is found that the red cells significantly augment the streamwise forces that must be resisted by the binding. However, interactions with the red cells are also found to cause an average wall-directed force, which can be anticipated to enhance binding. These forces increase significantly as hematocrit values approach 25% and decrease significantly as the leukocyte is made flatter on the wall. For a tube hematocrit of 25% and a spherical protrusion with a diameter three-quarters that of the vessel, the average forces are increased by ?40% and the local forces are more than double those estimated with an effective-viscosity-homogenized blood. Both the enhanced streamwise and wall-ward forces and their unsteady character are potentially important in regard to binding mechanisms.

Isfahani, Amir H.G.; Freund, Jonathan B.

2012-01-01

322

New approach to carbon monoxide poisoning treatment by laser-induced photodissociation of carboxyhemoglobin of cutaneous blood vessels  

Microsoft Academic Search

A new approach to carbon monoxide poisoning treatment based on laser-induced photodissociation of the carboxyhemoglobin is proposed. Using the simple model of laser tissue interaction the action spectra of laser radiation on carboxyhemoglobin of cutaneous blood vessels has been calculated. The results of the calculatoins indicate that there is a relatively narrow spectral range in the visible region where one

Mustafo M. Asimov; Rustam M. Asimov; Alexander Gisbrecht

2005-01-01

323

Taxane-induced Apoptosis Decompresses Blood Vessels and Lowers Interstitial Fluid Pressure in Solid Tumors: Clinical Implications1  

Microsoft Academic Search

Elevated tumor interstitial fluid pressure (IFP) is partly responsible for the poor penetration and distribution of therapeutic agents in solid tu- mors. The etiology of tumor interstitial hypertension is poorly understood. We have postulated that the solid stress generated by tumor cells growing in a confined space compresses blood vessels and increases tumor micro- vascular pressure and IFP. To test

Genevieve Griffon-Etienne; Yves Boucher; Christian Brekken; Herman D. Suit; Rakesh K. Jain

1999-01-01

324

Occlusion of cortical ascending venules causes blood flow decreases, reversals in flow direction, and vessel dilation in upstream capillaries  

Microsoft Academic Search

The accumulation of small strokes has been linked to cognitive dysfunction. Although most animal models have focused on the impact of arteriole occlusions, clinical evidence indicates that venule occlusions may also be important. We used two-photon excited fluorescence microscopy to quantify changes in blood flow and vessel diameter in capillaries after occlusion of single ascending or surface cortical venules as

John Nguyen; Nozomi Nishimura; Robert N Fetcho; Costantino Iadecola; Chris B Schaffer

2011-01-01

325

Ultrasonic Doppler measurements of blood flow velocity of rabbit retinal vessels using a 45-MHz needle transducer  

PubMed Central

Background The purpose of this study is to measure blood flow velocity of rabbit retinal vessels using a 45-MHz ultrasonic Doppler system with a needle transducer. Methods A high-frequency pulsed Doppler system that utilizes a 45-MHz PMN-PT needle transducer was developed to measure retinal blood flow velocity in situ. The pulsed Doppler allowed the differentiation of retinal from choroidal blood flow velocity. The needle transducer was inserted into the vitreous cavity through a 20-gauge incision port to access the retinal vessels. The first phase of the experiment evaluated the reproducibility of the measurements. The second phase measured velocities at four positions from the optic disc edge to the distal part of each vessel in nine eyes for the temporal and six eyes for the nasal portions. The angle between the transducer and the retinal vessel at each site was measured in enucleated rabbit eyes to estimate and compensate for measurement errors. Results In the first phase, the average measurement error was 5.97±1.34%. There was no significant difference comparing all eyes. In the second phase, the velocities gradually slowed from the disc edge to the distal part, and temporal velocities were faster than nasal velocities at all measurement sites. Conclusion This study demonstrated the feasibility of reliably measuring retinal blood flow velocity using a 45-MHz ultrasonic Doppler system with a needle transducer.

Matsuoka, Naoki; Paeng, Dong-Guk; Chen, Ruimin; Ameri, Hossein; Abdallah, Walid; Zhou, Qifa; Fawzi, Amani; Shung, K. K.

2010-01-01

326

3-D reconstruction of blood vessels in the ocular fundus from confocal scanning laser ophthalmoscope ICG angiography  

Microsoft Academic Search

The authors developed and tested a method to calculate three-dimensional image information of blood vessels in the living human eye. Their second aim was to elucidate the possibility of simultaneous angiography using two different fluorescent dyes. The authors used a confocal scanning laser ophthalmoscope for confocal sectioning of the posterior pole and simultaneous angiography with indocyanine green and fluorescein. They

Dirk-Uwe Bartsch; Arthur J. Mueller; Nathan O'Connor; Timothy Holmes; M. D. Freeman

1996-01-01

327

AN ACTIVATING MUTATION IN THE PLATELET-DERIVED GROWTH FACTOR RECEPTOR-? CAUSES EXCESSIVE BLOOD VESSEL FORMATION AND PLACENTAL DEFECTS  

Microsoft Academic Search

INTRODUCTION. The platelet-derived growth factors (PDGFs) and their cognate tyrosine kinase receptors are involved in multiple developmental processes. Signalling through the PDGF ?-receptor (PDGFR?) has, for instance, been shown to be involved in blood vessel formation (1). The PDGF signalling system is also an interesting target for treatment of several disorders as over- activity in this system has been linked

Camilla Looman; Peetra Magnusson; Aive Ahgren; Carl-Henrik Heldin; Reinald Fundele; Lena Cleasson-Welsh; Rainer Heuchel

328

Vessel Segmentation for Visualization of MRA with Blood Pool Contrast Agent  

Microsoft Academic Search

We present a method for the segmentation of vessel structures in 3D magnetic resonance angiography (MRA) images with bloodpool\\u000a contrast agent, allowing artery-vein separation for occluding vessel removal from MIP visualization. The method first uses\\u000a a front propagation algorithm to select a path along the vessel of interest. Two controlling speed functions are considered,\\u000a a multi-scale vessel filter, and an

Stewart Young; Vladimir Pekar; Jürgen Weese

2001-01-01

329

Comparing Two-Stent Strategies for Bifurcation Coronary Lesions: Which Vessel Should be Stented First, the Main Vessel or the Side Branch?  

PubMed Central

This study compared two-stent strategies for treatment of bifurcation lesions by stenting order, 'main across side first (A-family)' vs 'side branch first (S-family). The study population was patients from 16 centers in Korea who underwent drug eluting stent implantation with two-stent strategy (A-family:109, S-family:140 patients). The endpoints were cardiac death, myocardial infarction (MI), stent thrombosis (ST), and target lesion revascularization (TLR) during 3 years. During 440.8 person-years (median 20.2 months), there was 1 cardiac death, 4 MIs (including 2 STs), and 12 TLRs. Cumulative incidence of cardiac death, MI and ST was lower in A-family (0% in A-family vs 4.9% in S-family, P = 0.045). However, TLR rates were not different between the two groups (7.1% vs 6.2%, P = 0.682). Final kissing inflation (FKI) was a predictor of the hard-endpoint (hazard ratio 0.061; 95% CI 0.007-0.547, P = 0.013), but was not a predictor of TLR. The incidence of hard-endpoint of S-family with FKI was comparable to A-family, whereas S-family without FKI showed the poorest prognosis (1.1% vs 15.9%, retrospectively; P = 0.011). In conclusion, 'A-family' seems preferable to 'S-family' if both approaches are feasible. When two-stent strategy is used, every effort should be made to perform FKI, especially in 'S-family'.

Shin, Dong-Ho; Park, Kyung Woo; Koo, Bon-Kwon; Oh, Il-Young; Seo, Jae-Bin; Gwon, Hyeon-Cheol; Jeong, Myung-Ho; Seong, In-Whan; Rha, Seung Woon; Yang, Ju-Young; Park, Seung-Jung; Yoon, Jung Han; Han, Kyoo-Rok; Park, Jong-Sun; Hur, Seung-Ho; Tahk, Seung-Jea

2011-01-01

330

Real-Time Color-Doppler Guidance of HIFU for the Selective Avoidance or Occlusion of Blood Vessels  

NASA Astrophysics Data System (ADS)

High-intensity focused ultrasound (HIFU) has been shown to effectively occlude blood vessels deep within tissue. The objective of the current study was to synchronize HIFU and color-Doppler ultrasound (US) for the real-time visualization of flow within blood vessels during HIFU treatment. The excitation of the HIFU was synchronized with the color-Doppler imager by collecting the excitation pulses of one of the elements of either a curved array intracavitary (C 9-5) or an intraoperative (CL 10-5) imaging probe. The collected excitation pulse was converted into a TTL-high pulse, which was delayed and gated to time the excitation duration and location of the HIFU pulse with respect to each imaging frame. The single pulse was used to drive a 3.2 MHz concave HIFU transducer (focal length of 3.5 cm, f-number 1) while the US imager was not collecting RF signals from the treatment region of the US image. The feasibility of the system was demonstrated in vivo by the selective ablation of tissue adjacent to, or the occlusion of, large vessels (including the femoral artery) both transcutaneously and interoperatively in the rabbit and pig. For the occlusion of vessels, the HIFU focus was placed immediately distal (with respect to the transducer) to the vessel at a depth of 2-2.5 cm. HIFU was applied at in situ intensities of 1000-2000 W/cm2, at a duty cycle of 50-75%, and a HIFU pulse repetition frequency (set by the US image frame rate) of 6-18 Hz. During each HIFU exposure, the HIFU pulse resulted in color interference bands running vertically within the color-Doppler window. Through the synchronization of the US imager with the HIFU excitation, the location and duration of the interference bands were set outside the treatment region within each image frame. This provided the operator with a clear view of the HIFU treatment site during therapy. Gross assessment showed necrosis of the tissue surrounding the HIFU treated vessel and occlusion of vessels up to 4 mm in diameter after a 30 s HIFU exposure. We have developed a method of synchronizing pulsed HIFU with color-Doppler US imaging for the real-time visualization of flow within blood vessels during HIFU therapy. This provides a means of guiding HIFU therapy for the detection and occlusion of deep vessels, or the selective ablation of tissue surrounding the vessels without vascular occlusion.

Rabkin, Brian A.; Zderic, Vesna; Vaezy, Shahram

2005-03-01

331

Detection of blood vessels in human brain 3D magnetic resonance images with the use of mathematical morphology and region growing algorithms  

NASA Astrophysics Data System (ADS)

Detection and quantitative parameterization of brain blood vessels in magnetic resonance images (MRI) are an important aid to diagnosing neoplasmic diseases, planning surgical operations or detecting the atrophy of blood vessels. Fast and effective computer programs are needed to extract quantitative information from MRI data - to increase objectivity, accuracy and repeatability of the diagnosis. To develop such programs we must use algorithms for 3D images segmentation, necessary to build geometrical models of the blood vessels. These models are then used for vessel tree visualization and quantitative description.

Sankowski, Adam; Materka, Andrzej

2009-06-01

332

Heat transfer inside the tissues with a supplying vessel for the case when metabolic heat generation and blood perfusion are temperature dependent  

Microsoft Academic Search

The heat transfer within a perfused tissue in the presence of a supplying vessel is considered. Approximate analytical solutions\\u000a are obtained for the case when the arterial temperature of the perfused blood in the bio-heat transfer equation varies along\\u000a the direction of the vessel and is equal to the axially varying mixed mean temperature of the blood in the vessel.

K. N. Rai; S. K. Rai

1999-01-01

333

PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning  

PubMed Central

We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance.

Sriram, Krishna; Tsai, Amy G.; Cabrales, Pedro; Meng, Fantao; Acharya, Seetharama A.; Tartakovsky, Daniel M.

2012-01-01

334

PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning.  

PubMed

We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance. PMID:22505638

Sriram, Krishna; Tsai, Amy G; Cabrales, Pedro; Meng, Fantao; Acharya, Seetharama A; Tartakovsky, Daniel M; Intaglietta, Marcos

2012-04-13

335

Gamma-Secretase Inhibitor Treatment Promotes VEGF-A-Driven Blood Vessel Growth and Vascular Leakage but Disrupts Neovascular Perfusion  

PubMed Central

The Notch signaling pathway is essential for normal development due to its role in control of cell differentiation, proliferation and survival. It is also critically involved in tumorigenesis and cancer progression. A key enzyme in the activation of Notch signaling is the gamma-secretase protein complex and therefore, gamma-secretase inhibitors (GSIs)—originally developed for Alzheimer's disease—are now being evaluated in clinical trials for human malignancies. It is also clear that Notch plays an important role in angiogenesis driven by Vascular Endothelial Growth Factor A (VEGF-A)—a process instrumental for tumor growth and metastasis. The effect of GSIs on tumor vasculature has not been conclusively determined. Here we report that Compound X (CX), a GSI previously reported to potently inhibit Notch signaling in vitro and in vivo, promotes angiogenic sprouting in vitro and during developmental angiogenesis in mice. Furthermore, CX treatment suppresses tumor growth in a mouse model of renal carcinoma, leads to the formation of abnormal vessels and an increased tumor vascular density. Using a rabbit model of VEGF-A-driven angiogenesis in skeletal muscle, we demonstrate that CX treatment promotes abnormal blood vessel growth characterized by vessel occlusion, disrupted blood flow, and increased vascular leakage. Based on these findings, we propose a model for how GSIs and other Notch inhibitors disrupt tumor blood vessel perfusion, which might be useful for understanding this new class of anti-cancer agents.

Kalen, Mattias; Nitzsche, Anja; Weber, Holger; Esser, Norbert; Yla-Herttuala, Seppo; Hellstrom, Mats

2011-01-01

336

Gamma-secretase inhibitor treatment promotes VEGF-A-driven blood vessel growth and vascular leakage but disrupts neovascular perfusion.  

PubMed

The Notch signaling pathway is essential for normal development due to its role in control of cell differentiation, proliferation and survival. It is also critically involved in tumorigenesis and cancer progression. A key enzyme in the activation of Notch signaling is the gamma-secretase protein complex and therefore, gamma-secretase inhibitors (GSIs)--originally developed for Alzheimer's disease--are now being evaluated in clinical trials for human malignancies. It is also clear that Notch plays an important role in angiogenesis driven by Vascular Endothelial Growth Factor A (VEGF-A)--a process instrumental for tumor growth and metastasis. The effect of GSIs on tumor vasculature has not been conclusively determined. Here we report that Compound X (CX), a GSI previously reported to potently inhibit Notch signaling in vitro and in vivo, promotes angiogenic sprouting in vitro and during developmental angiogenesis in mice. Furthermore, CX treatment suppresses tumor growth in a mouse model of renal carcinoma, leads to the formation of abnormal vessels and an increased tumor vascular density. Using a rabbit model of VEGF-A-driven angiogenesis in skeletal muscle, we demonstrate that CX treatment promotes abnormal blood vessel growth characterized by vessel occlusion, disrupted blood flow, and increased vascular leakage. Based on these findings, we propose a model for how GSIs and other Notch inhibitors disrupt tumor blood vessel perfusion, which might be useful for understanding this new class of anti-cancer agents. PMID:21533193

Kalén, Mattias; Heikura, Tommi; Karvinen, Henna; Nitzsche, Anja; Weber, Holger; Esser, Norbert; Ylä-Herttuala, Seppo; Hellström, Mats

2011-04-14

337

Blood brain barrier breakdown as the starting point of cerebral small vessel disease? - New insights from a rat model  

PubMed Central

Cerebral small vessel disease (CSVD, cerebral microangiopathy) leads to dementia and stroke-like symptoms. Lacunes, white matter lesions (WML) and microbleeds are the main pathological correlates depicted in in-vivo imaging diagnostics. Early studies described segmental arterial wall disorganizations of small penetrating cerebral arteries as the most pronounced underlying histopathology of lacunes. Luminal narrowing caused by arteriolosclerosis was supposed to result in hypoperfusion with WML and infarcts. We have used the model of spontaneously hypertensive stroke-prone rats (SHRSP) for a longitudinal study to elucidate early histological changes in small cerebral vessels. We suggest that endothelial injuries lead to multiple sites with blood brain barrier (BBB) leakage which cause an ongoing damage of the vessel wall and finally resulting in vessel ruptures and microbleeds. These microbleeds together with reactive small vessel occlusions induce overt cystic infarcts of the surrounding parenchyma. Thus, multiple endothelial leakage sites seem to be the starting point of cerebral microangiopathy. The vascular system reacts with an activated coagulatory state to these early endothelial injuries and by this induces the formation of stases, accumulations of erythrocytes, which represent the earliest detectable histological peculiarity of small vessel disease in SHRSP. In this review we focus on the meaning of the BBB breakdown in CSVD and finally discuss possible consequences for clinicians.

2013-01-01

338

Numerical investigation of the non-Newtonian pulsatile blood flow in a bifurcation model with a non-planar branch  

Microsoft Academic Search

The pulsatile flow of non-Newtonian fluid in a bifurcation model with a non-planar daughter branch is investigated numerically by using the Carreau–Yasuda model to take into account the shear thinning behavior of the analog blood fluid. The objective of this study is to deal with the influence of the non-Newtonian property of fluid and of out-of-plane curvature in the non-planar

Jie Chen; Xi-Yun Lu

2006-01-01

339

Numerical investigation of the non-Newtonian blood flow in a bifurcation model with a non-planar branch  

Microsoft Academic Search

The non-Newtonian fluid flow in a bifurcation model with a non-planar daughter branch is investigated by using finite element method to solve the three-dimensional Navier–Stokes equations coupled with a non-Newtonian constitutive model, in which the shear thinning behavior of the blood fluid is incorporated by the Carreau–Yasuda model. The objective of this study is to investigate the influence of the

Jie Chen; Xi-Yun Lu

2004-01-01

340

Formation of an artificial blood vessel: adhesion force measurements with optical tweezers  

NASA Astrophysics Data System (ADS)

We are investigating the formation of a tissue capsule around a foreign body. This tissue capsule can be used as an autologous graft for the replacement of diseased blood vessels or for bypass surgery. The graft is grown in the peritoneal cavity of the recipient and the formation starts with the adhesion of cells to the foreign body. We identify the cell type and measure the adhesion of these cells to foreign materials using optical tweezers. Cell adhesion to macroscopic samples and microspheres is investigated. No difference in the adhesion force was measurable for polyethylene, silicon and Tygon on a scale accessible to optical tweezers. The density of adherent cells was found to vary strongly, being highest on polyethylene. The mean rupture forces for cell-microsphere adhesion ranged from 24 to 39 pN and changed upon preadsorption of bovine serum albumin. For plain microspheres, the highest mean rupture force was found for PMMA, which also showed the highest adhesion probability for the cell-microsphere interaction.

Knoener, Gregor; Campbell, Julie H.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina

2004-10-01

341

Low-density lipoprotein transport in blood vessel walls of squirrel monkeys  

SciTech Connect

Transmural accumulations of low-density lipoprotein (LDL) were examined in the blood vessel walls of four squirrel monkeys. Vascular wall concentrations of LDL were measured using quantitative autoradiography after {sup 125}I-labeled LDL circulation for 30 min. Profiles of relative tissue concentration from different sections in the same region were similar to each other, and there was little animal-to-animal variation. Concentrations were highest near the luminal endothelium, lower near the medial-adventitial border, and lowest within the media. Profiles from different regions fell into three groups: (1) aortic samples had steep intimal concentration gradients and near-zero media concentrations; (2) the iliac, femoral, popliteal, and common carotid arteries had higher intimal concentrations than group 1 but had similar concentrations deep within the media; and (3) the cerebral and coronary arteries, inferior vena cava, and pulmonary artery had intimal concentrations that were similar to group 2, but the concentrations deep within the media were greater than either groups 1 or 2. Arterial bifurcation profiles from the inner wall and the outer walls were similar to each other and to profiles from the upstream and downstream areas. Out of 280 total sites examined, 15 examples of profiles with substantially increased concentrations near the luminal endothelium were found scattered throughout the cardiovascular system, demonstrating that there are focal regions throughout the cardiovascular system which have greatly increased {sup 125}I-LDL transendothelial permeability.

Tompkins, R.G.; Yarmush, M.L.; Schnitzer, J.J.; Colton, C.K.; Smith, K.A.; Stemerman, M.B. (Harvard Medical School, Boston, MA (USA))

1989-08-01

342

Potential Approaches to Enhance the Effects of Estrogen on Senescent Blood Vessels and Postmenopausal Cardiovascular Disease  

PubMed Central

Cardiovascular disease (CVD) is more common in postmenopausal than premenopausal women, suggesting vascular protective effects of estrogen. Vascular estrogen receptors ER?, ER? and a transmembrane estrogen-binding protein GPR30 have been described. Also, experimental studies have demonstrated vasodilator effects of estrogen on the endothelium, vascular smooth muscle and extracellular matrix. However, randomized clinical trials have not supported vascular benefits of menopausal hormone therapy (MHT), possibly due to the subjects' advanced age and age-related changes in estrogen synthesis and metabolic pathways, the vascular ERs number, distribution and integrity, and the post-ER vascular signaling pathways. Current MHT includes natural estrogens such as conjugated equine estrogen, as well as synthetic and semi-synthetic estrogens. New estrogenic formulations and hormone combinations have been developed. Phytoestrogens is being promoted as an alternative MHT. Specific ER modulators (SERMs), and selective agonists for ER? such as PPT, ER? such as DPN, and GPR30 such as G1 are being evaluated. In order to enhance the vascular effectiveness of MHT, its type, dose, route of administration and timing may need to be customized depending on the subject's age and pre-existing CVD. Also, the potential interaction of estrogen with progesterone and testosterone on vascular function may need to be considered in order to maximize the vascular benefits of MHT on senescent blood vessels and postmenopausal CVD.

Khalil, Raouf A.

2010-01-01

343

Preliminary investigation of the feasibility of magnetic propulsion for future microdevices in blood vessels.  

PubMed

The Magnetic Resonance Submarine (MR-Sub) project is a first attempt to validate a new propulsion method for future small magnetically controlled microdevices suited for minimally invasive applications in blood vessels. A Magnetic Resonance Imaging (MRI) system provides the driving force in three dimensions to a ferromagnetic core that could be embedded onto a specialised microdevice. The paper describes preliminary tests made to match the magnetic force induced by an MRI system on a ferromagnetic sphere with the drag force it encompasses in a cylindrical tube. These tests provide a proof of concept demonstrating that this new method of propulsion is very promising within the constraints of such types of operations. This conclusion is based on specific measurements showing that 1010/1020 carbon steel spheres (3.175 mm and 2.381 mm in diameter) can withstand a maximum flow of 0.370 +/- 0.0064 l/min (19.5 cm/s) and 0.311 +/- 0.01209 l/min (16.4 cm/s) respectively when placed inside a 6.35 mm diameter PMMA tube and subjected to a 18 mT/m magnetic field gradient. PMID:16179757

Mathieu, Jean-Baptiste; Martel, Sylvain; Yahia, L'Hocine; Soulez, Gilles; Beaudoin, Gilles

2005-01-01

344

Rupture Properties of Blood Vessel Walls Measured by Pressure-Imposed Test  

NASA Astrophysics Data System (ADS)

It is expected to be clinically useful to know the mechanical properties of human aortic aneurysms in assessing the potential for aneurysm rupture. For this purpose, a newly designed experimental setup was fabricated to measure the rupture properties of blood vessel walls. A square specimen of porcine thoracic aortas is inflated by air pressure at a rate of 10mmHg/s (?1.3MPa/s) until rupture occurs. Mean breaking stress was 1.8±0.4 MPa (mean±SD) for the specimens proximal to the heart and 2.3±0.8MPa for the distal specimens, which are not significantly different to those values obtained longitudinally from conventional tensile tests. Moreover, the local breaking stretch ratio in the longitudinal direction was significantly higher at the ruptured site (2.7±0.5) than at the unruptured site (2.2±0.4). This testing system for studying the rupture properties of aortic walls is expected to be applicable to aortic aneurysms. Experimental verification of the present technique for the homogeneous, isotropic material is also presented.

Ohashi, Toshiro; Sugita, Syukei; Matsumoto, Takeo; Kumagai, Kiichiro; Akimoto, Hiroji; Tabayashi, Koichi; Sato, Masaaki

345

Evaluation of local density enhancement of microcapsules in artificial blood vessel during exposure to focused ultrasound  

NASA Astrophysics Data System (ADS)

We have proposed a physical DDS (Drug Delivery System) which makes use of microcapsules of ?m size, which may contain a specified drug and also are easily affected by ultrasound exposure near their resonant frequency, to release various kinds of medications. These capsules are easily detected and actuated by ultrasound. However, because of the diffusion of capsules after injection into human body, it was difficult to enhance the efficiency of drug delivery. Thus we have considered a method for controlling the density of capsules in flow which uses acoustic radiation force, which moves the capsules to balance flow resistance. We have experimented with trapping microcapsules or microbubbles in flow of an artificial blood vessel. We have evaluated the effect of radiation force by measuring the trapped area of capsules or bubbles for various frequencies, sound pressures, and exposure times of sinusoidal ultrasound. The trapped area of capsules or bubbles increased with sound pressure and exposure time, and decreased with frequency. From those results, we have derived optimal conditions for trapping the capsules or bubbles.

Nakamoto, Ryusuke; Masuda, Kohji; Watarai, Nobuyuki; Taguchi, Yuto; Kato, Toshikazu; Yoshinaga, Takashi; Miyamoto, Yoshitaka; Chiba, Toshio

2011-09-01

346

Due to intravascular multiple sequential scattering, Diffuse Correlation Spectroscopy of tissue primarily measures relative red blood cell motion within vessels.  

PubMed

We suggest that Diffuse Correlation Spectroscopy (DCS) measurements of tissue blood flow primarily probe relative red blood cell (RBC) motion, due to the occurrence of multiple sequential scattering events within blood vessels. The magnitude of RBC shear-induced diffusion is known to correlate with flow velocity, explaining previous reports of linear scaling of the DCS "blood flow index" with tissue perfusion despite the observed diffusion-like auto-correlation decay. Further, by modeling RBC mean square displacement using a formulation that captures the transition from ballistic to diffusive motion, we improve the fit to experimental data and recover effective diffusion coefficients and velocity de-correlation time scales in the range expected from previous blood rheology studies. PMID:21750779

Carp, Stefan A; Roche-Labarbe, Nadàege; Franceschini, Maria-Angela; Srinivasan, Vivek J; Sakadži?, Sava; Boas, David A

2011-06-24

347

Investigation of source-detector separation optimization for an implantable perfusion and oxygenation sensor for liver blood vessels  

SciTech Connect

An implanted system is being developed to monitor transplanted liver health during the critical 7-10 day period posttransplantation. The unit will monitor organ perfusion and oxygen consumption using optically-based probes placed on both the inflow and outflow blood vessels, and on the liver parenchymal surface. Sensing probes are based on a 3- wavelength LED source and a photodiode detector. Sample diffuse reflectance is measured at 735, 805, and 940 nm. To ascertain optimal source-to-photodetector spacing for perfusion measurement in blood vessels, an ex vivo study was conducted. In this work, a dye mixture simulating 80% blood oxygen saturation was developed and perfused through excised porcine arteries while collecting data for various preset probe source-to-photodetector spacings. The results from this study demonstrate a decrease in the optical signal with decreasing LED drive current and a reduction in perfusion index signal with increasing probe spacing. They also reveal a 2- to 4-mm optimal range for blood vessel perfusion probe source-to-photodetector spacing that allows for sufficient perfusion signal modulation depth with maximized signal to noise ratio (SNR). These findings are currently being applied to guide electronic configuration and probe placement for in vivo liver perfusion porcine model studies.

Baba, Justin S [ORNL; Akl, Tony [Texas A& M University; Cote, Gerard L. [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL

2011-01-01

348

Investigation of source-detector separation optimization for an implantable perfusion and oxygenation sensor for liver blood vessels  

NASA Astrophysics Data System (ADS)

An implanted system is being developed to monitor transplanted liver health during the critical 7-10 day period posttransplantation. The unit will monitor organ perfusion and oxygen consumption using optically-based probes placed on both the inflow and outflow blood vessels, and on the liver parenchymal surface. Sensing probes are based on a 3- wavelength LED source and a photodiode detector. Sample diffuse reflectance is measured at 735, 805, and 940 nm. To ascertain optimal source-to-photodetector spacing for perfusion measurement in blood vessels, an ex vivo study was conducted. In this work, a dye mixture simulating 80% blood oxygen saturation was developed and perfused through excised porcine arteries while collecting data for various preset probe source-to-photodetector spacings. The results from this study demonstrate a decrease in the optical signal with decreasing LED drive current and a reduction in perfusion index signal with increasing probe spacing. They also reveal a 2- to 4-mm optimal range for blood vessel perfusion probe source-to-photodetector spacing that allows for sufficient perfusion signal modulation depth with maximized signal to noise ratio (SNR). These findings are currently being applied to guide electronic configuration and probe placement for in vivo liver perfusion porcine model studies.

Baba, J. S.; Akl, T. J.; Coté, G. L.; Wilson, M. A.; Ericson, M. N.

2011-02-01

349

[Effect of new synthetic anxiolytic selank on gastric wall blood flow and mesenteryc lymphatic vessels contractility in anesthetized rats].  

PubMed

The influence of a new heptapeptide Selank on microcirculation in anesthetized white rats was investigated. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a new synthetic anxiolytic which exerts obvious antiulcerogenic action and promotes healing of experimental ulcers. Action of the peptide on gastric blood flow in the stomach by using the method ofhydrogenic clearance and Selank action on mesenteric lymphatic contractility by microscopical observation in situ, were studied. Selank fail to influence basal gastric blood flow but it can normalize blood flow reduced by indomethacin. The study of dose-depended of Selank effect on lymphatic vessels contractility showed that its low concentration (10(-12)--10(-14) M) enhanced amplitude and increase frequency of lymphatic vessel contractions which indicates an enhancement of lymphatic flow. The high doses of peptide (10(-6)--10(-10) M) also augmented the contraction amplitude but decreased its frequency. The maintenance of adequate blood flow and lymphatic vessel contractility can be one of the mechanisms of the Selank antiulcerogenic properties. PMID:15835541

Pavlov, T S; Sanzhieva, L Ts; Samonina, G E; Sergeev, V I; Lelekova, T V

2005-02-01

350

Perpendicular Blood Vessel Seals Are Stronger Than Those Made at an Angle  

PubMed Central

Abstract Vessel sealing devices effectively produce hemostatic seals with minimal thermal damage, but the strength of seals decreases as vessel diameter increases. Because vessels sealed at an angle to the vessel require a greater functional seal diameter than those sealed perpendicularly to the vessel, it was hypothesized that perpendicular seals would have comparably higher burst pressures. Ex vivo, porcine carotid arteries of nominal diameters of 5, 6, and 7?mm were sealed perpendicularly to and at a 45° angle to the longitudinal axis of the vessels, and burst pressures of the sealed vessels were measured. Overall burst pressures were 51% greater for perpendicular seals than for angled seals (P<.001). Mean burst pressures for the 5-mm angled and 7-mm perpendicular groups, which have similar seal lengths, were not significantly different (P=.959). Analysis using the functional diameter as a covariate indicated that the seal length is the primary variable in determining burst pressure, and not some other inherent characteristic of angled versus perpendicular sealing. These results suggest that at least for vessels ?5?mm in diameter, surgeons should approach vessels perpendicularly and not at an angle, for the highest possible seal strength. The development of articulated sealing and cutting devices would provide greater seal strength, in addition to improved maneuverability, especially in laparoscopic surgery, where angles of approach may be limited by the fixed location of surface cannulas.

Voegele, Aaron C.; Korvick, Donna L.; Gutierrez, Mario; Amaral, Joseph F.

2013-01-01

351

Electrical communication in branching arterial networks  

PubMed Central

Electrical communication and its role in blood flow regulation are built on an examination of charge movement in single, isolated vessels. How this process behaves in broader arterial networks remains unclear. This study examined the nature of electrical communication in arterial structures where vessel length and branching were varied. Analysis began with the deployment of an existing computational model expanded to form a variable range of vessel structures. Initial simulations revealed that focal endothelial stimulation generated electrical responses that conducted robustly along short unbranched vessels and to a lesser degree lengthened arteries or branching structures retaining a single branch point. These predictions matched functional observations from hamster mesenteric arteries and support the idea that an increased number of vascular cells attenuate conduction by augmenting electrical load. Expanding the virtual network to 31 branches revealed that electrical responses increasingly ascended from fifth- to first-order arteries when the number of stimulated distal vessels rose. This property enabled the vascular network to grade vasodilation and network perfusion as revealed through blood flow modeling. An elevation in endothelial-endothelial coupling resistance, akin to those in sepsis models, compromised this ascension of vasomotor/perfusion responses. A comparable change was not observed when the endothelium was focally disrupted to mimic disease states including atherosclerosis. In closing, this study highlights that vessel length and branching play a role in setting the conduction of electrical phenomenon along resistance arteries and within networks. It also emphasizes that modest changes in endothelial function can, under certain scenarios, impinge on network responsiveness and blood flow control.

Tran, Cam Ha T.; Vigmond, Edward J.; Goldman, Daniel; Plane, France

2012-01-01

352

Electrical communication in branching arterial networks.  

PubMed

Electrical communication and its role in blood flow regulation are built on an examination of charge movement in single, isolated vessels. How this process behaves in broader arterial networks remains unclear. This study examined the nature of electrical communication in arterial structures where vessel length and branching were varied. Analysis began with the deployment of an existing computational model expanded to form a variable range of vessel structures. Initial simulations revealed that focal endothelial stimulation generated electrical responses that conducted robustly along short unbranched vessels and to a lesser degree lengthened arteries or branching structures retaining a single branch point. These predictions matched functional observations from hamster mesenteric arteries and support the idea that an increased number of vascular cells attenuate conduction by augmenting electrical load. Expanding the virtual network to 31 branches revealed that electrical responses increasingly ascended from fifth- to first-order arteries when the number of stimulated distal vessels rose. This property enabled the vascular network to grade vasodilation and network perfusion as revealed through blood flow modeling. An elevation in endothelial-endothelial coupling resistance, akin to those in sepsis models, compromised this ascension of vasomotor/perfusion responses. A comparable change was not observed when the endothelium was focally disrupted to mimic disease states including atherosclerosis. In closing, this study highlights that vessel length and branching play a role in setting the conduction of electrical phenomenon along resistance arteries and within networks. It also emphasizes that modest changes in endothelial function can, under certain scenarios, impinge on network responsiveness and blood flow control. PMID:22796538

Tran, Cam Ha T; Vigmond, Edward J; Goldman, Daniel; Plane, France; Welsh, Donald G

2012-07-13

353

Chronic hydrocephalus-induced hypoxia: increased expression of VEGFR-2+ and blood vessel density in hippocampus  

PubMed Central

Chronic hydrocephalus (CH) is a neurological disease characterized by increased cerebrospinal fluid volume and pressure that is often associated with impaired cognitive function. By and large, CH is a complex and heterogeneous CSF disorder where the exact site of brain insult is uncertain. Several mechanisms including neural compression, fiber stretch, and local or global hypoxia have been implicated in the underlying pathophysiology of CH. Specifically, the hippocampus, which plays a significant role in memory processing and is in direct contact with expanding CSF ventricles, may be involved. Using our model of chronic hydrocephalus, we quantified the density of VEGFR-2+ neurons, glial, endothelial cells, and blood vessels in hippocampal regions CA1, CA2-3, dentate gyrus and hilus using immunohistochemical and stereological methods. Density and %VEGFR-2+ cell populations were estimated for CH animals (2–3 weeks vs 12–16 weeks) and Surgical Controls (SC). Overall, we found approximately 6–8 fold increase in the cellular density of VEGFR-2+ and more than double BVd in the hippocampus of CH compared with SC. There were no significant regional differences in VEGFR-2+ cellular and BV density expression in the CH group. VEGFR-2+ and BV densities were significantly related to changes in CSF volume (p?0.05), and not ICP. The %VEGFR-2+ was significantly greater in CH than SC (p?0.05), and was significantly correlated with BV density (p?0.05). These results showed that CH elicited a profound increase in VEGFR-2+ in hippocampus that corresponded to increased BV density. It was unclear whether increased VEGFR-2+ and BV expression was related to focal compression alone or in combination with global ischemia/hypoxia conditions as previously described. These findings suggest that VEGFR-2 may play an adaptive role in angiogenesis after CH-induced hypoxia. Modulation of VEGF/VEGFR-2+ may be important in developing treatments for hypoxic conditions including hydrocephalus and other forms of cerebral ischemia.

Dombrowski, Stephen M.; Deshpande, Abhishek; Dingwall, Cameron; Leichliter, Anna; Leibson, Zack; Luciano, Mark G.

2008-01-01

354

Estrogenic Compounds, Estrogen Receptors and Vascular Cell Signaling in the Aging Blood Vessels  

PubMed Central

The cardiovascular benefits of menopausal hormone therapy (MHT) remain controversial. The earlier clinical observations that cardiovascular disease (CVD) was less common in MHT users compared to non-users suggested cardiovascular benefits of MHT. Also, experimental studies have identified estrogen receptors ER?, ER? and GPR30, which mediate genomic or non-genomic effects in vascular endothelium, smooth muscle, and extracellular matrix (ECM). However, data from randomized clinical trials (RCTs), most notably the Women's Health Initiative (WHI) study, have challenged the cardiovascular benefits and highlighted adverse cardiovascular events with MHT. The discrepancies have been attributed to the design of RCTs, the subjects' advanced age and preexisting CVD, and the form of estrogen used. The discrepancies may also stem from age-related changes in vascular ER amount, distribution, integrity, and post-receptor signaling pathways as well as structural changes in the vasculature. Age-related changes in other sex hormones such as testosterone may also alter the hormonal environment and influence the cardiovascular effects of estrogen. Investigating the chemical properties, structure-activity relationship and pharmacology of natural and synthetic estrogens should improve the effectiveness of conventional MHT. Further characterization of phytoestrogens, selective estrogen-receptor modulators (SERMs), and specific ER agonists may provide substitutes to conventional MHT. Conditions with excess or low estrogen levels such as polycystic ovary syndrome (PCOS) and Turner syndrome may provide insight into the development and regulation of ER and the mechanisms of aberrant estrogen-ER interactions. The lessons learned from previous RCTs have led to more directed studies such as the Kronos Early Estrogen Prevention Study (KEEPS). Careful design of experimental models and RCTs, coupled with the development of specific ER modulators, hold the promise of improving the actions of estrogen in the aging blood vessels and thereby enhancing the efficacy and safety of MHT in postmenopausal CVD.

Smiley, Dia A.; Khalil, Raouf A.

2010-01-01

355

Relation of Blood Pressure to Retinal Vessel Diameter in Type 1 Diabetes Mellitus  

PubMed Central

Objective To examine the relationship of blood pressure (BP) and use of angiotensin receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACEI) to retinal vessel diameter in normotensive, normoalbuminuric persons with type 1 diabetes mellitus (T1DM). Design Randomized controlled clinical trial. Participants Persons with T1DM and gradable fundus photographs both at baseline (n=147) and 5-year follow-up (n=124). Methods Clinic and 24-hour ambulatory BPs (ABP) were measured. Retinal arteriolar and venular diameters were measured using a computer-assisted technique. Individual arteriolar and venular measurements were combined into summary indices that reflect the average retinal arteriolar (central retinal arteriolar equivalent [CRAE]) and venular (central retinal venular equivalent [CRVE]) diameter of an eye, respectively. Main Outcome Measures CRAE and CRVE. Results While controlling for age, study site, glycosylated hemoglobin and ambulatory pulse rate, daytime ambulatory systolic (-0.29 ?m effect per 1mmHg, P=.02) and daytime ambulatory diastolic (-0.44 ?m effect per 1mmHg, P=.04), nighttime ambulatory systolic (-0.27 ?m effect per 1mmHg, P=.03), and 24-hour ambulatory systolic BP (-0.31 ?m effect per 1mmHg, P=.03) were cross-sectionally associated with a smaller CRAE. While controlling for age, study site, glycosylated hemoglobin, ambulatory pulse rate and baseline CRAE, no BP measure was associated with a change in CRAE or CRVE over 5 years of follow-up. Treatment with losartan or enalapril was not associated with a statistically significant change in CRAE or CRVE. Conclusions ACEI or ARB therapy does not affect retinal arteriolar or venular diameter in normotensive persons with T1DM.

Klein, Ronald; Myers, Chelsea E.; Klein, Barbara E. K.; Zinman, Bernard; Gardiner, Robert; Suissa, Samy; Sinaiko, Alan R.; Donnelly, Sandra M.; Goodyer, Paul; Strand, Trudy; Mauer, Michael

2009-01-01

356

Increased Superoxide and Endothelial NO Synthase Uncoupling in Blood Vessels of Bmal1-Knockout Mice  

PubMed Central

Rationale Disruption of the circadian clock in mice produces vascular dysfunction as evidenced by impairments in endothelium-dependent signaling, vasomotion, and blood vessel remodeling. Although the altered function of endothelial NO synthase and the overproduction of reactive oxygen species are central to dysfunction of the endothelium, to date, the impact of the circadian clock on endothelial NO synthase coupling and vascular reactive oxygen species production is not known. Objective The goals of the present study were to determine whether deletion of a critical component of the circadian clock, Bmal1, can influence endothelial NO synthase coupling and reactive oxygen species levels in arteries from Bmal1-knockout (KO) mice. Methods and Results Endothelial function was reduced in aortae from Bmal1-KO mice and improved by scavenging reactive oxygen species with polyethylene glycol-superoxide dismutase and nonselectively inhibiting cyclooxygenase isoforms with indomethacin. Aortae from Bmal1-KO mice exhibited enhanced superoxide levels as determined by electron paramagnetic resonance spectroscopy and dihydroethidium fluorescence, an elevation that was abrogated by administration of nitro-L -arginine methyl ester. High-performance liquid chromatography analysis revealed a reduction in tetrahydrobiopterin and an increase in dihydrobiopterin levels in the lung and aorta of Bmal1-KO mice, whereas supplementation with tetrahydrobiopterin improved endothelial function in the circadian clock KO mice. Furthermore, levels of tetrahydrobiopterin, dihydrobiopterin, and the key enzymes that regulate biopterin bioavailability, GTP cyclohydrolase and dihydrofolate reductase exhibited a circadian expression pattern. Conclusions Having an established influence in the metabolic control of glucose and lipids, herein, we describe a novel role for the circadian clock in metabolism of biopterins, with a significant impact in the vasculature, to regulate coupling of endothelial NO synthase, production of superoxide, and maintenance of endothelial function. (Circ Res. 2012; 111:1157–1165.)

Anea, Ciprian B.; Cheng, Bo; Sharma, Shruti; Kumar, Sanjiv; Caldwell, R. William; Yao, Lin; Ali, M. Irfan; Merloiu, Ana M.; Stepp, David W.; Black, Stephen M.; Fulton, David J.R.; Rudic, R. Daniel

2013-01-01

357

Glycoprotein 115, a glycoprotein isolated from chick blood vessels, is widely distributed in connective tissue  

PubMed Central

An extracellular glycoprotein (gp 115) with an apparent Mr = 115,000 isolated from chick aortas (Bressan, G. M., I. Castellani, A. Colombatti, and D. Volpin, 1983, J. Biol. Chem., 258:13262-13267), was used to immunize mice. The antisera were shown to specifically recognize gp 115 by numerous criteria: a major band around Mr = 115,000 plus minor bands of lower Mr were visible by immunoblotting on aorta extracts, and a similar pattern was observed with a monoclonal antibody; no cross-reactivity was detected by radioimmunobinding with other extracellular proteins, namely, fibronectin, laminin, and collagen types I, III, IV, V, and VI. Antigen distribution on frozen tissue sections from newborn chicks was investigated by using affinity- purified antibody. Strong immunoreactivity was always found in blood vessels. In the digestive tract, the fluorescent staining was localized both at the level of muscular layers and in the stromal matrix of the villi. Within skeletal muscle and myocardium, staining was associated with large connective tissue bundles and the matrix around each muscle fiber. Intense fluorescence was observed in the kidney, in smooth muscle cells rich areas of parabronchi, and within the portal space and along liver sinusoids. The antigen was not detected at the epidermal- dermal junction; immunoreactivity in the dermis was present as a diffuse fibrillar pattern. That the antigen detected by immunofluorescence in the various organs was indeed gp 115 was demonstrated by immunoblotting analysis: as in aorta extracts, a major band around Mr = 115,000 was detected in several tissues. Antibody- reacting material was also incorporated into the extracellular matrix produced by embryo smooth muscle cells grown in vitro and was organized as a meshwork of fine fibrils.

1985-01-01

358

Acetylcholine-induced relaxation in blood vessels from endothelial nitric oxide synthase knockout mice  

PubMed Central

Isometric tension was recorded in isolated rings of aorta, carotid, coronary and mesenteric arteries taken from endothelial nitric oxide synthase knockout mice (eNOS(?/?) mice) and the corresponding wild-type strain (eNOS(+/+) mice). The membrane potential of smooth muscle cells was measured in coronary arteries with intracellular microelectrodes.In the isolated aorta, carotid and coronary arteries from the eNOS(+/+) mice, acetylcholine induced an endothelium-dependent relaxation which was inhibited by N?-L-nitro-arginine. In contrast, in the mesenteric arteries, the inhibition of the cholinergic relaxation required the combination of N?-L-nitro-arginine and indomethacin.The isolated aorta, carotid and coronary arteries from the eNOS(?/?) mice did not relax in response to acetylcholine. However, acetylcholine produced an indomethacin-sensitive relaxation in the mesenteric artery from eNOS(?/?) mice.The resting membrane potential of smooth muscle cells from isolated coronary arteries was significantly less negative in the eNOS(?/?) mice (?64.8±1.8?mV, n=20 and ?58.4±1.9?mV, n=17, for eNOS(+/+) and eNOS(?/?) mice, respectively). In both strains, acetylcholine, bradykinin and substance P did not induce endothelium-dependent hyperpolarizations whereas cromakalim consistently produced hyperpolarizations (?7.9±1.1?mV, n=8 and ?13.8±2.6?mV, n=4, for eNOS(+/+) and eNOS(?/?) mice, respectively).These findings demonstrate that in the blood vessels studied: (1) in the eNOS(+/+) mice, the endothelium-dependent relaxations to acetylcholine involve either NO or the combination of NO plus a product of cyclo-oxygenase but not EDHF; (2) in the eNOS(?/?) mice, NO-dependent responses and EDHF-like responses were not observed. In the mesenteric arteries acetylcholine releases a cyclo-oxygenase derivative.

Chataigneau, Thierry; Feletou, Michel; Huang, Paul L; Fishman, Mark C; Duhault, Jacques; Vanhoutte, Paul M

1999-01-01

359

A modified ferric tannate method for visualizing a blood vessel and its usage in the study of spinal cord injury  

Microsoft Academic Search

Study design:To develop a method for the study of spinal cord injury (SCI) that can visualize the blood vessels and is compatible with hematoxylin and eosin (HE) staining and immunohistochemical techniques.Objective:Visualization of the vascular changes is important for the study of SCI. The original ferric tannate method can stain the spinal cord vasculature to its terminals, but the diffuse tannate

X-F Shen; Y Zhao; Y-K Zhang; L-Y Jia; G Ju

2009-01-01

360

Endothelial cells expressing Bcl-2 promotes tumor metastasis by enhancing tumor angiogenesis, blood vessel leakiness and tumor invasion.  

PubMed

Metastatic spread of tumor cells to vital organs is the major cause of mortality in cancer patients. Bcl-2, a key antiapoptotic protein, is expressed at high levels in a number of human tumors. We have recently shown that Bcl-2 is also overexpressed in tumor-associated blood vessels in head-and-neck cancer patients. Interestingly, enhanced Bcl-2 expression in tumor blood vessels is directly correlated with metastatic status of these cancer patients. In addition, endothelial cells (ECs) expressing Bcl-2 showed increased production of interleukin-8 (IL-8) resulting in significantly enhanced tumor cell proliferation and tumor cell invasion. Therefore, we hypothesized that Bcl-2 expression in tumor-associated ECs may promote tumor metastasis by enhancing tumor cell invasiveness and release in the circulation. To test our hypothesis, we coimplanted tumor cells along with ECs expressing Bcl-2 (EC-Bcl-2) in the flanks of SCID mice. Our results demonstrate that incorporation of EC-Bcl-2 in primary tumors significantly enhanced tumor cell metastasis to lungs and this EC-Bcl-2-mediated tumor metastasis was independent of primary tumor size. In addition, Bcl-2-mediated tumor metastasis directly correlated with increased tumor angiogenesis. Bcl-2 expression in ECs also promoted transendothelial cell permeability, blood vessel leakiness and tumor cell invasion. EC-Bcl-2-mediated tumor cell proliferation and tumor cell invasion were significantly mediated by IL-8. These results suggest that Bcl-2, when expressed at higher levels in tumor-associated ECs, may promote tumor metastasis by enhancing tumor angiogenesis, blood vessel leakiness and tumor cell invasiveness. PMID:18490895

Kumar, Pawan; Ning, Yu; Polverini, Peter J

2008-05-19

361

Simulation study on acoustic streaming and convective cooling in blood vessels during a high-intensity focused ultrasound thermal ablation  

Microsoft Academic Search

This study investigates the influence of blood vessels on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors. A three-dimensional acoustics-thermal-fluid coupling model is simulated to compute the temperature field in the hepatic cancerous region. The model is based on the linear Westervelt and bioheat equations as well as the non-linear Navier–Stokes equations for the liver parenchyma and

Maxim A. Solovchuk; Tony W. H. Sheu; Win-Li Lin; Ihyuan Kuo; Marc Thiriet

362

BMP4 and noggin control embryonic blood vessel formation by antagonistic regulation of VEGFR-2 ( Quek1) expression  

Microsoft Academic Search

Regulation of VEGFR-2 (Quek1) is an important mechanism during blood vessel formation. In the paraxial mesoderm, Quek1 expression is restricted to the lateral portion of the somite and later to sclerotomal cells surrounding the neural tube. By grafting of either intermediate mesoderm or BMP4 beads into the paraxial mesoderm, we show that BMP4 is a positive regulator of VEGFR-2 (Quek1)

Suresh Nimmagadda; Poongodi Geetha Loganathan; Ruijin Huang; Martin Scaal; Corina Schmidt; Bodo Christ

2005-01-01

363

Precise manipulation of a microrobot in the pulsatile flow of human blood vessels using magnetic navigation system  

NASA Astrophysics Data System (ADS)

This paper proposes a method to precisely manipulate a microrobot in the pulsatile flow that simulates the flow characteristics of human blood vessels by utilizing the electromagnetic transfer function of a magnetic navigation system (MNS). The frequency response characteristics of the MNS were utilized so that the input voltages in each coil can precisely generate the required time-varying magnetic force of a microrobot. An experiment which successfully anchoring a microrobot in a pulsatile flow was conducted to verify the proposed method.

Jeon, S. M.; Jang, G. H.; Choi, J. H.; Park, S. H.; Park, J. O.

2011-04-01

364

Changes in the distribution of endothelial surface glycoconjugates associated with altered permeability of brain micro-blood vessels  

Microsoft Academic Search

Lectin-binding sites located on the endothelial cell (EC) surfaces in unaltered, leaking and resorbing micro-blood vessels (MBVs) in cryo-injured cat brain were studied. Lectin or glycoprotein-gold complexes and brain samples embedded in hydrophilic resin Lowicryl K4M were used. The lectins tested recognize the following residues: ß-d-galactosyl (Ricinus communis agglutinin 120, RCA and peanut agglutinin, PNA), sialyl (Limax flavus agglutinin),N-acetyl-d-galactosaminyl (Helix

A. W. Vorbrodt

1986-01-01

365

Effects of a monoclonal anti-?v?3 integrin antibody on blood vessels—A pharmacodynamic study  

Microsoft Academic Search

Summary  \\u000a Purpose: The integrin ?v?3 is an adhesion molecule expressed by proliferating endothelial cells and antibodies blocking this integrin inhibit angiogenesis in preclinical models. MEDI-522 is a second generation humanized anti-?v?3 antibody designed for antiangiogenic therapy. The purpose of this study was to examine potential effects of this agent on blood vessels.\\u000a Experimental design: In a phase I dose escalation

Dahua Zhang; Thomas Pier; Douglas G. McNeel; George Wilding; Andreas Friedl

2007-01-01

366

Association of type I neurons positive for NADPH-diaphorase with blood vessels in the adult monkey corpus callosum.  

PubMed

Sagittal sections through the corpus callosum of adult macaque monkeys (n?=?7) reveal a subpopulation of neurons positive for NADPH-diaphorase (NADPHd). These are sparsely distributed, with 2-12 neurons scored over the anterior two-thirds of the callosum (about 14?mm). Neurons are densely labeled, type 1; but on the basis of soma and dendritic morphology, these neurons exhibit distinct heterogeneity. In one subpopulation, the cell body is narrowly attenuated (7-10??m in width). These have bipolar dendrites, extending 300-800??m from the cell body. One or both of the dendrites is often closely associated with blood vessels and tends to be aligned dorso-ventral, perpendicular to the body of the callosum. Another subpopulation of neurons has a larger soma (typically, 15??m?×?20??m) and more multipolar dendrites, which are not as obviously associated with blood vessels. White matter neurons positive for NADPHd have previously been observed as a transient population, most numerous during development, in the human corpus callosum, as well as in that of other species. Their persistence in the corpus callosum of adult macaques and their close association with blood vessels has not previously been reported and is suggestive of roles other than axon guidance. PMID:22363265

Rockland, Kathleen S; Nayyar, Naema

2012-02-20

367

Assessment of the intimal response to a protein-modified stent in a tissue-engineered blood vessel mimic.  

PubMed

Protein-coated intravascular stents have emerged as potential pro-healing modifications for or alternatives to anti-proliferative drug-eluting stents. To support the development of these devices, preclinical testing is required to evaluate the intimal response to new coatings and modifications. The purpose of this work was to implement a tissue-engineered blood vessel as an in vitro testing system to evaluate extracellular matrix-modified stents with regard to endothelialization of the stent surface. Stents were modified by submersion in a protein-enriched medium and were subsequently deployed within tissue-engineered blood vessels and cultivated in vitro under flow to assess the intimal response. Scanning electron microscopy, fluorescent nuclear staining with en face imaging, and histological assessments were performed 7 or 14 days postdeployment. Results illustrated accelerated cellular regeneration over protein-modified stent strut surfaces, with increased coverage and increased tissue thickness atop protein-modified stent struts. In addition, the intimal response to modified stents differed significantly from bare metal stents. Conclusions from this work support the use of a tissue-engineered blood vessel mimic system for evaluation of modified stent surfaces. These findings are important to stent researchers as well as laboratories developing tissue-engineered constructs. PMID:19563259

Cardinal, Kristen O'Halloran; Williams, Stuart K

2009-12-01

368

Association of Type I Neurons Positive for NADPH-Diaphorase with Blood Vessels in the Adult Monkey Corpus Callosum  

PubMed Central

Sagittal sections through the corpus callosum of adult macaque monkeys (n?=?7) reveal a subpopulation of neurons positive for NADPH-diaphorase (NADPHd). These are sparsely distributed, with 2–12 neurons scored over the anterior two-thirds of the callosum (about 14?mm). Neurons are densely labeled, type 1; but on the basis of soma and dendritic morphology, these neurons exhibit distinct heterogeneity. In one subpopulation, the cell body is narrowly attenuated (7–10??m in width). These have bipolar dendrites, extending 300–800??m from the cell body. One or both of the dendrites is often closely associated with blood vessels and tends to be aligned dorso-ventral, perpendicular to the body of the callosum. Another subpopulation of neurons has a larger soma (typically, 15??m?×?20??m) and more multipolar dendrites, which are not as obviously associated with blood vessels. White matter neurons positive for NADPHd have previously been observed as a transient population, most numerous during development, in the human corpus callosum, as well as in that of other species. Their persistence in the corpus callosum of adult macaques and their close association with blood vessels has not previously been reported and is suggestive of roles other than axon guidance.

Rockland, Kathleen S.; Nayyar, Naema

2012-01-01

369

Possible role of mural cell-covered mature blood vessels in inducing drug resistance in cancer-initiating cells.  

PubMed

Cancer recurrence has been suggested to be induced by residual cancer-initiating cells (CICs) or cancer stem cells (CSCs) after chemotherapy. Moreover, it is possible that CICs/CSCs acquire more aggressive behavior after therapy as shown by invasion and metastasis. In the cancer microenvironment, CICs/CSCs may localize in a specific area, the so-called stem cell niche, and isolation of this niche is important to elucidate the molecular mechanism of how CICs/CSCs acquire malignancy. We analyzed whether CICs acquire drug resistance after cancer drug treatment in a tumor cell allograft model in which we could identify and isolate living CICs by detecting a higher level of transcriptional activity of the PSF1 gene promoter. In our models using Lewis lung carcinoma (LLC) mouse lung cancer and colon26 mouse colon cancer cell lines, we found that CICs in both tumors acquired drug resistance after cancer drug treatment. Interestingly, response to the anticancer drug was quite different between LLC and colon26 original tumors (ie, the proportion of CICs in LLC tumors increased but in colon26 tumors the proportion decreased). We found that CICs frequently localized near mature blood vessels in which endothelial cells were covered with mural cells and that the incidence of mature blood vessels in LLC tumors was four times higher than in colon26 tumors. These results suggest a relationship between mature blood vessels and CIC drug resistance. PMID:23473746

Matsui, Takahiro; Kinugasa, Yumi; Tahara, Hidekazu; Kanakura, Yuzuru; Takakura, Nobuyuki

2013-03-07

370

Laser-optical method of visualization the local net of tissue blood vessels and its biomedical applications  

NASA Astrophysics Data System (ADS)

New approach in laser-optical diagnostic methods of cell metabolism based on visualization the local net of tissue blood vessels is proposed. Optical model of laser - tissue interaction and algorithm of mathematical calculation of optical signals is developed. Novel technology of local tissue hypoxia elimination based on laser-induced photodissosiation of oxyhemoglobin in cutaneous blood vessels is developed. Method of determination of oxygen diffusion coefficient into tissue on the base of kinetics of tissue oxygenation TcPO2 under the laser irradiation is proposed. The results of mathematical modeling the kinetic of oxygen distribution into tissue from arterial blood are presented. The possibility of calculation and determination of the level of TcPO2 in zones with the disturbed blood microcirculation is demonstrated. The increase of the value of oxygen release rate more than for times under the irradiation by laser light is obtained. It is shown that the efficiency of laser-induced oxygenation by means of increasing oxygen concentration in blood plasma is comparable with the method of hyperbaric oxygenation (HBO) at the same time gaining advantages in local action. Different biomedical applications of developing method are discussed.

Asimov, M. M.; Asimov, R. M.; Rubinov, A. N.

2007-08-01

371

Fasciocutaneous vessels  

Microsoft Academic Search

Summary In the conventional view of the arterial blood supply of skin, two systems of vessels are recognised; the direct cutaneous arteries and the musculocutaneous perforators. The existence of a third system consisting of fasciocutaneous perforators, is a relatively new concept. These vessels supply the skin by passing along the fascial septa between adjacent muscles. A particular feature of these

G. C. Cormack; B. G. H. Lamberty

1984-01-01

372

Segmentation of retinal blood vessels by combining the detection of centerlines and morphological reconstruction.  

PubMed

This paper presents an automated method for the segmentation of the vascular network in retinal images. The algorithm starts with the extraction of vessel centerlines, which are used as guidelines for the subsequent vessel filling phase. For this purpose, the outputs of four directional differential operators are processed in order to select connected sets of candidate points to be further classified as centerline pixels using vessel derived features. The final segmentation is obtained using an iterative region growing method that integrates the contents of several binary images resulting from vessel width dependent morphological filters. Our approach was tested on two publicly available databases and its results are compared with recently published methods. The results demonstrate that our algorithm outperforms other solutions and approximates the average accuracy of a human observer without a significant degradation of sensitivity and specificity. PMID:16967805

Mendonça, Ana Maria; Campilho, Aurélio

2006-09-01

373

In vivo two-photon excited fluorescence microscopy reveals cardiac- and respiration-dependent pulsatile blood flow in cortical blood vessels in mice  

PubMed Central

Subtle alterations in cerebral blood flow can impact the health and function of brain cells and are linked to cognitive decline and dementia. To understand hemodynamics in the three-dimensional vascular network of the cerebral cortex, we applied two-photon excited fluorescence microscopy to measure the motion of red blood cells (RBCs) in individual microvessels throughout the vascular hierarchy in anesthetized mice. To resolve heartbeat- and respiration-dependent flow dynamics, we simultaneously recorded the electrocardiogram and respiratory waveform. We found that centerline RBC speed decreased with decreasing vessel diameter in arterioles, slowed further through the capillary bed, and then increased with increasing vessel diameter in venules. RBC flow was pulsatile in nearly all cortical vessels, including capillaries and venules. Heartbeat-induced speed modulation decreased through the vascular network, while the delay between heartbeat and the time of maximum speed increased. Capillary tube hematocrit was 0.21 and did not vary with centerline RBC speed or topological position. Spatial RBC flow profiles in surface vessels were blunted compared with a parabola and could be measured at vascular junctions. Finally, we observed a transient decrease in RBC speed in surface vessels before inspiration. In conclusion, we developed an approach to study detailed characteristics of RBC flow in the three-dimensional cortical vasculature, including quantification of fluctuations in centerline RBC speed due to cardiac and respiratory rhythms and flow profile measurements. These methods and the quantitative data on basal cerebral hemodynamics open the door to studies of the normal and diseased-state cerebral microcirculation.

Santisakultarm, Thom P.; Cornelius, Nathan R.; Nishimura, Nozomi; Schafer, Andrew I.; Silver, Richard T.; Doerschuk, Peter C.; Olbricht, William L.

2012-01-01

374

Identification and characterization of the blood vessels of solid tumors that are leaky to circulating macromolecules.  

PubMed Central

The tumor microvasculature is hyperpermeable to plasma proteins, but the specific vessels that leak have not been identified. To investigate this question, the extravasation of circulating tracers of varying size was studied by fluorescence, light, and electron microscopy in animals bearing solid transplantable carcinomas. In all five tumors studied, 70 and 150 kD fluoresceinated (FITC)-dextrans and colloidal carbon leaked extensively from the prominent vascular plexus that was induced around individual tumor nodules and at the tumor-host interface. Leaky vessels were mature veins or venules, lined by a continuous endothelium; most had closed interendothelial cell junctions. Immature interface vessels and tumor-penetrating vessels did not leak these macromolecular tracers significantly. Three kD of FITC-dextran leaked from peripherally situated tumor veins or venules but also extravasated from tumor-penetrating vessels and capillaries supplying normal tissues. These data correlate the functional and anatomic heterogeneity of tumor vessels and provide a rationale for the distribution of circulating molecules such as monoclonal antibodies and tumoricidal drugs in solid tumors. Images Figure 3 Figure 5 Figure 1 Figure 4 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Dvorak, H. F.; Nagy, J. A.; Dvorak, J. T.; Dvorak, A. M.

1988-01-01

375

Deep in vivo two-photon imaging of blood vessels with a new dye encapsulated in pluronic nanomicelles  

NASA Astrophysics Data System (ADS)

Our purpose is to test if Pluronic® fluorescent nanomicelles can be used for in vivo two-photon imaging of both the normal and the tumor vasculature. The nanomicelles were obtained after encapsulating a hydrophobic two-photon dye: di-stryl benzene derivative, in Pluronic block copolymers. Their performance with respect to imaging depth, blood plasma staining, and diffusion across the tumor vascular endothelium is compared to a classic blood pool dye Rhodamin B dextran (70 kDa) using two-photon microscopy. Pluronic nanomicelles show, like Rhodamin B dextran, a homogeneous blood plasma staining for at least 1 h after intravenous injection. Their two-photon imaging depth is similar in normal mouse brain, using 10 times less injected mass. In contrast with Rhodamin B dextran, no extravasation is observed in leaky tumor vessels due to their large size: 20-100 nm. In conclusion, Pluronic nanomicelles can be used as a blood pool dye, even in leaky tumor vessels. The use of Pluronic block copolymers is a valuable approach for encapsulating two-photon fluorescent dyes that are hydrophobic and not suitable for intravenous injection.

Maurin, Mathieu; Stéphan, Olivier; Vial, Jean-Claude; Marder, Seth R.; van der Sanden, Boudewijn

2011-03-01

376

Heterogeneous histochemical reaction pattern of the lectin Bandeiraea (Griffonia) simplicifolia with blood vessels of human full-term placenta.  

PubMed

Bandeiraea simplicifolia lectin (BS-I) stains vascular endothelium in various species. In humans, less than 10% of the specimens studied exhibit a reaction with BS-I. In the present histochemical study, the reactivity of BS-I with placental blood vessels and its correlation with the blood group from mother and newborn child was investigated. Acetone-fixed cryosections of representative tissue segments of human full-term placenta and umbilical cord were stained with BS-I. The staining pattern of tissues from patients with different blood groups was identical, although the reaction of BS-I in the placenta was heterogeneous. BS-I did not react with the umbilical cord. Vascular smooth muscle cells at the insertion site of the umbilical cord into the chorionic plate, and endothelium deeper in the chorionic plate, became progressively stained. The endothelial cells and tunica muscularis of smaller arteries and veins in stem villi lost their reactivity in parallel with decreasing vessel size. Arterioles and venules reacted heterogeneously. Capillaries, trophoblastic basement membranes, especially epithelial plates, and sometimes the syncytiotrophoblast were labelled in several terminal villi. The data indicate that 1) the placenta binds BS-I to fetal endothelium independent of the blood group, 2) cell-surface antigens on placental endothelial cells are expressed heterogeneously and 3) cell-surface glycans are constituted in an organ-specific manner on human endothelial cells. PMID:7850854

Lang, I; Hahn, T; Dohr, G; Skofitsch, G; Desoye, G

1994-12-01

377

Effect of non-Newtonian characteristics of blood on magnetic targeting in the impermeable micro-vessel  

NASA Astrophysics Data System (ADS)

In this investigation we consider to extended the work of Furlani and Furlani [15] by taking non-Newtonian fluid model for the blood in the impermeable micro-vessel. The behavior of blood is considered as the Herschel-Bulkley fluid which is more suitable for the micro-vessel of radius 50 ?m. The expression for the fluidic force for the carrier particle traversing in the Herschel-Bulkley fluid is obtained first. Several factors that influence the magnetic targeting of the carrier particles in the microvasculature, such as the size of the carrier particle, the volume fraction of embedded magnetic nanoparticles, and the diameter of the micro-vessel are considered in the present problem. An algorithm is given to solve the system of coupled equations for trajectories of the carrier particle in the invasive case. The trajectories of the carrier particles are found in both invasive and noninvasive targeting systems. A comparison is make regarding the trajectories in these cases. Also, a prediction of the capture of therapeutic magnetic nanoparticle in the human microvasculature is made for different radii and volume fractions in both the invasive and noninvasive cases.

Shaw, Sachin; Murthy, P. V. S. N.; Pradhan, S. C.

2010-04-01

378

Branch ligatures and blood aspiration for post-traumatic superficial temporal artery pseudoaneurysm: surgical technique.  

PubMed

The aim of this study is to report a new minimally invasive technique of superficial temporal artery (STA) pseudoaneurysm treatment. Several surgical options have been employed to treat STA pseudoaneurysms. To address this rare condition, the employed techniques are ligation and excision of the aneurysm, endovascular coil embolization or percutaneous ultrasound-guided thrombin injection. Between techniques no significant differences are reported in terms of outcomes. The decision to adopt a technique depends on STA pseudoaneurysm morphology and surgeon preference. In the present report, STA pseudoaneurysm afferent and efferent branches were identified by ultrasound in a 92-year-old female. Under local anaesthesia, these branches were ligated through small skin incisions. STA pseudoaneurysm decompression was obtained by an 'over the needle aspiration'. A compressive dressing was left in space for 48 h. PMID:23404313

Rancic, Zoran; Pecoraro, Felice; Nigro, Gianluigi; Simon, Roger; Frauenfelder, Thomas; Mayer, Dieter; Lachat, Mario

2013-02-13

379

Angiogenic factor signaling regulates centrosome duplication in endothelial cells of developing blood vessels.  

PubMed

Regulated vascular endothelial growth factor (VEGF) signaling is required for proper angiogenesis, and excess VEGF signaling results in aberrantly formed vessels that do not function properly. Tumor endothelial cells have excess centrosomes and are aneuploid, properties that probably contribute to the morphologic and functional abnormalities of tumor vessels. We hypothesized that endothelial cell centrosome number is regulated by signaling via angiogenic factors, such as VEGF. We found that endothelial cells in developing vessels exposed to elevated VEGF signaling display centrosome overduplication. Signaling from VEGF, through either MEK/ERK or AKT to cyclin E/Cdk2, is amplified in association with centrosome overduplication, and blockade of relevant pathway components rescued the centrosome overduplication defect. Endothelial cells exposed to elevated FGF also had excess centrosomes, suggesting that multiple angiogenic factors regulate centrosome number. Endothelial cells with excess centrosomes survived and formed aberrant spindles at mitosis. Developing vessels exposed to elevated VEGF signaling also exhibited increased aneuploidy of endothelial cells, which is associated with cellular dysfunction. These results provide the first link between VEGF signaling and regulation of the centrosome duplication cycle, and suggest that endothelial cell centrosome overduplication contributes to aberrant angiogenesis in developing vessel networks exposed to excess angiogenic factors. PMID:20664058

Taylor, Sarah M; Nevis, Kathleen R; Park, Hannah L; Rogers, Gregory C; Rogers, Stephen L; Cook, Jeanette G; Bautch, Victoria L

2010-07-27

380

Angiogenic factor signaling regulates centrosome duplication in endothelial cells of developing blood vessels  

PubMed Central

Regulated vascular endothelial growth factor (VEGF) signaling is required for proper angiogenesis, and excess VEGF signaling results in aberrantly formed vessels that do not function properly. Tumor endothelial cells have excess centrosomes and are aneuploid, properties that probably contribute to the morphologic and functional abnormalities of tumor vessels. We hypothesized that endothelial cell centrosome number is regulated by signaling via angiogenic factors, such as VEGF. We found that endothelial cells in developing vessels exposed to elevated VEGF signaling display centrosome overduplication. Signaling from VEGF, through either MEK/ERK or AKT to cyclin E/Cdk2, is amplified in association with centrosome overduplication, and blockade of relevant pathway components rescued the centrosome overduplication defect. Endothelial cells exposed to elevated FGF also had excess centrosomes, suggesting that multiple angiogenic factors regulate centrosome number. Endothelial cells with excess centrosomes survived and formed aberrant spindles at mitosis. Developing vessels exposed to elevated VEGF signaling also exhibited increased aneuploidy of endothelial cells, which is associated with cellular dysfunction. These results provide the first link between VEGF signaling and regulation of the centrosome duplication cycle, and suggest that endothelial cell centrosome overduplication contributes to aberrant angiogenesis in developing vessel networks exposed to excess angiogenic factors.

Taylor, Sarah M.; Nevis, Kathleen R.; Park, Hannah L.; Rogers, Gregory C.; Rogers, Stephen L.; Cook, Jeanette G.

2010-01-01

381

Contribution of bone marrow-derived cells to blood vessels in ischemic tissues and tumors.  

PubMed

Vessels are formed during embryonic development through three distinct processes. Angiogenesis and arteriogenesis involve the remodeling of established capillary networks and arterioles, while vasculogenesis involves the differentiation of mesodermal progenitor cells called angioblasts into mature endothelial cells. Until recently, postnatal vessel development was felt to occur exclusively through angiogenesis or arteriogenesis. However, recent studies using experimental tumor and ischemia models have raised controversy regarding whether vasculogenesis occurs in postnatal vessel development, with some studies suggesting the possibility and others refuting it. Here, we summarize the process of embryonic vessel development and review studies investigating the role of postnatal vasculogenesis in vessel formation in adult ischemia and tumors. We then focus on studies in which wild-type and genetically modified vascular progenitor cells have been investigated as possible cellular therapies for tumors or ischemia. We also take note of key issues that will need to be understood about the biology of vasculogenesis before cellular therapies utilizing vascular progenitor cells can be finally taken from the bench to the bedside. PMID:16137927

Aghi, Manish; Chiocca, E Antonio

2005-08-30

382

Thermal damage of blood vessels in a rat skin-flap window chamber using indocyanine green and a pulsed alexandrite laser: A feasibility study  

Microsoft Academic Search

The design criteria and feasibility of specifically targeting blood vessels for thermal damage by using a pulsed alexandrite\\u000a infra-red laser to heat an intravascularly injected infra-redabsorbing dye, namely indocyanine green (ICG), is demonstrated.\\u000a Theoretical calculations map the distribution of light and heat in and around the subcutaneous blood vessels in a rat skin-flap\\u000a window chamber as functions of dye concentration,

Stephen T. Flock; Steven L. Jacques

1993-01-01

383

[Effect of cavinton on the indices of carbohydrate metabolism in the blood vessel wall].  

PubMed

Effect of cavinton on contents of pyruvic and lactic acids in the walls of the femoral and carotid arteries as well as the abdominal aorta and its arch was studied at administration for 3, 5 and 7 days to rabbits. Cavinton was shown to contribute to general aerobization of carbohydrate catabolism in the vessel wall. The femoral and carotid arteries were found to be the most reactive vessels. In experimental pituitrine-induced pathology a general decrease of carbohydrate catabolism was observed. PMID:2454202

Turkova, L A

384

Ricinus communis Agglutinin I Leads to Rapid Down-Regulation of VEGFR-2 and Endothelial Cell Apoptosis in Tumor Blood Vessels  

PubMed Central

Ricinus communis agglutinin I (RCA I), a galactose-binding lectin from castor beans, binds to endothelial cells at sites of plasma leakage, but little is known about the amount and functional consequences of binding to tumor endothelial cells. We addressed this issue by examining the effects of RCA I on blood vessels of spontaneous pancreatic islet-cell tumors in RIP-Tag2 transgenic mice. After intravenous injection, RCA I bound strongly to tumor vessels but not to normal blood vessels. At 6 minutes, RCA I fluorescence of tumor vessels was largely diffuse, but over the next hour, brightly fluorescent dots appeared as the lectin was internalized by endothelial cells. RCA I injection led to a dose- and time-dependent decrease in vascular endothelial growth factor receptor-2 (VEGFR-2) immunoreactivity in tumor endothelial cells, with 95% loss over 6 hours. By comparison, VEGFR-3, CD31, and CD105 had decreases in the range of 21% to 33%. Loss of VEGFR-2 was followed by increased activated caspase-3 in tumor vessels. Prior inhibition of VEGF signaling by AG-028262 decreased RCA I binding and internalization into tumor vessels. These findings indicate RCA I preferentially binds to and is internalized by tumor endothelial cells, which leads to VEGFR-2 down-regulation, endothelial cell apoptosis, and tumor vessel regression. Together, the results illustrate the selective impact of RCA I on VEGF signaling in tumor blood vessels.

You, Weon-Kyoo; Kasman, Ian; Hu-Lowe, Dana D.; McDonald, Donald M.

2010-01-01

385

Blood levels of branched-chain alpha-keto acids in uremia: effect of an oral glucose tolerance test.  

PubMed

The effect of an oral glucose tolerance test (oGTT) on serum levels of branched-chain keto acids (BCKA), i.e. alpha-keto-isocaproic acid (KICA), alpha-keto-isovaleric acid (KIVA) and alpha-keto-beta methyl-n-valeric acid (KMVA) as well as on serum insulin, C-peptide and blood glucose levels was determined in uremic patients and in healthy control subjects. In controls, blood levels of KICA, KMVA and KIVA declined significantly following oral administration of 100 glucose. In uremic patients no decline of KICA was observed. The fall of KMVA was diminished, while suppression of KIVA blood levels in response to the oGGT remained unimpaired. Although serum insulin and C-peptide levels in uremic patients were not significantly different from the controls before and throughout the oGTT, six out of eight displayed abnormal glucose tolerance. It is suggested that the response of blood BCKA levels to an oGTT is altered in uremia, an abnormality restricted primarily to KICA and possibly explained by insulin antagonism and/or by insufficient insulin secretion. PMID:7021997

Schauder, P; Matthaei, D; Henning, H V; Scheler, F; Langenbeck, U

1981-08-01

386

Expression and functional significance of NADPH oxidase 5 (Nox5) and its splice variants in human blood vessels  

PubMed Central

The expression and functional significance of NADPH oxidase 5 (Nox5) and its five isoforms in vascular cells is poorly understood. The goal of this study was to determine whether Nox5-?, -?, -?, -?, and -? (short) are expressed in human blood vessels and evaluate their respective functions. Nox5 mRNA and protein were detected in human blood vessels, cultured human vascular smooth muscle (HVSMC) and endothelium, but not fibroblasts. The most abundant isoforms were ? and ?, whereas ? and ? were not detected. Nox5-? and -? produced reactive oxygen species (ROS), but -?, -?, and -? were not catalytically active. Coexpression of the active Nox5 isoforms with inactive Nox5 variants suppressed ROS production, and coimmunoprecipitation revealed that Nox5-? binds the inactive ? variant, which may account for reduced ROS production. In HVSMC, angiotensin II, endothelin-1 and TNF-? increased endogenous Nox5 mRNA levels, while adenovirus-mediated overexpression of Nox5 promoted p38 MAPK, JAK2, JNK, and ERK1/2 phosphorylation in endothelial cells (EC), but only increased ERK1/2 phosphorylation in HVSMC. At higher levels of Nox5, there was evidence of increased apoptosis in EC, but not in HVSMC, as detected by the presence of cleaved caspase-3 and cleaved poly(ADP-ribose)polymerase. Although catalytically inactive, Nox5-? potently activated ERK in HVSMC, and increased expression of Nox5-? promoted HVSMC proliferation. Nox5 is expressed in human blood vessels. The Nox5-? and -? splice variants are the major isoforms that are expressed and the only variants capable of ROS production. Nox5-? can inhibit Nox5 activity and activate ERK and HVSMC proliferation.

Pandey, Deepesh; Patel, Anand; Patel, Vijay; Chen, Feng; Qian, Jin; Wang, Yusi; Barman, Scott A.; Venema, Richard C.; Stepp, David W.; Daniel Rudic, R.

2012-01-01

387

Finite element analysis of nonlinear pulsatile suspension flow dynamics in blood vessels with aneurysm  

Microsoft Academic Search

A nonlinear pulsatile suspension flow in a dilated vessel is numerically analysed. Two sets of highly coupled nonlinear partial differential equations governing the suspension flow are numerically solved, to simulate the suspension flow dynamics. A transient velocity-pressure (UVP) finite element method (FEM) and a stable time integration scheme, based on a predictorcorrector strategy, with constant error monitoring are employed in

B. V. Rathish Kumar; K. B. Naidu

1995-01-01

388

A space–time analysis of blood flow in a 3D vessel with multiple aneurysms  

Microsoft Academic Search

In this study, 3D unsteady flow dynamics in an arterial vessel with two asymmetric aneurysms in series have been numerically investigated under pulsatile flow conditions for a full cycle of period T. The non-linear partial differential equations governing the conservation of mass and momentum of viscous incompressible fluid have been numerically analysed by a time accurate cell centered finite volume

B. V. Rathish Kumar

2003-01-01

389

Effect of conservation with metaperiodate and glutaraldehyde on the immunogenic properties of blood vessels  

Microsoft Academic Search

Experiments on guinea pigs and rabbits showed that treatment of human femoral vessels with solutions of metaperiodate and glutaraldehyde sharply reduces (to one-tenth) the content of water-soluble proteins in tissue homogenates, depresses the sensitizing and anaphylactogenic activity of the extracts, and leads to inertia in the precipitation test with homologous antiserum against native tissue.

L. S. Barbarash; V. N. Sergeev

1978-01-01

390

Effect of rheological property on blood flow in vertebral artery branch  

NASA Astrophysics Data System (ADS)

Blocking of an artery is one of mechanisms for cerebral stroke development. If an important cerebral artery is occluded by any reason and if there is no sufficient collaterals, tissue ischemia occurs at brain tissues distal to the occluded artery, which is a well known clinical situation. However, in practice, ischemia or hypoperfusion has also been observed through the branches proximal to the occluded artery. The unexpected ``proximal ischemia'' is not yet known, from which patients could suffer serious complications. In the present study, two patient cases are presented to elucidate this phenomenon from the view point of fluid dynamics, especially with emphasis on the role of rheology in hemodynamics.

Min, Taegee; Kim, Myungjoon; Kim, Taesung; Kwon, O.-Ki

2011-11-01

391

Active Blood Vessel Formation in the Ischemic Hindlimb Mouse Model Using a Microsphere\\/Hydrogel Combination System  

Microsoft Academic Search

Purpose  We hypothesize that the controlled delivery of rhVEGF using a microsphere\\/hydrogel combination system could be useful to achieve\\u000a active blood vessel formation in the ischemic hindlimb mouse model, which is clinically relevant for therapeutic angiogenesis\\u000a without multiple administrations.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  A combination of poly(d,l-lactide-co-glycolide) (PLGA) microspheres and alginate hydrogels containing rhVEGF was prepared and injected intramuscularly into the\\u000a ischemic hindlimb site of

Jangwook Lee; Suk Ho Bhang; Byung-Soo Kim; Kuen Yong Lee

2010-01-01

392

Biophysical Properties of Scaffolds Modulate Human Blood Vessel Formation from Circulating Endothelial Colony-Forming Cells  

NASA Astrophysics Data System (ADS)

A functional vascular system forms early in development and is continually remodeled throughout the life of the organism. Impairment to the regeneration or repair of this system leads to tissue ischemia, dysfunction, and disease. The process of vascular formation and remodeling is complex, relying on local microenvironmental cues, cytokine signaling, and multiple cell types to function properly. Tissue engineering strategies have attempted to exploit these mechanisms to develop functional vascular networks for the generation of artificial tissues and therapeutic strategies to restore tissue homeostasis. The success of these strategies requires the isolation of appropriate progenitor cell sources which are straightforward to obtain, display high proliferative potential, and demonstrate an ability to form functional vessels. Several populations are of interest including endothelial colony-forming cells, a subpopulation of endothelial progenitor cells. Additionally, the development of scaffolds to deliver and support progenitor cell survival and function is crucial for the formation of functional vascular networks. The composition and biophysical properties of these scaffolds have been shown to modulate endothelial cell behavior and vessel formation. However, further investigation is needed to better understand how these mechanical properties and biophysical properties impact vessel formation. Additionally, several other cell populations are involved in neoangiogenesis and formation of tissue parenchyma and an understanding of the potential impact of these cell populations on the biophysical properties of scaffolds will also be needed to advance these strategies. This chapter examines how the biophysical properties of matrix scaffolds can influence vessel formation and remodeling and, in particular, the impact on in vivo human endothelial progenitor cell vessel formation.

Critser, Paul J.; Yoder, Mervin C.

393

Small vessel hematocrit in ischemic myocardium  

SciTech Connect

As blood enters the microvasculature of normally perfused myocardium, there is a progressive decrease in small vessel hematocrit (SV Hct) due to RBC streaming in smaller branching vessels and the Fahraeus-Lindqvist effect. We hypothesized that if the coronary collateral circulation was composed of very small vessels branching from large parent vessels, plasma streaming would result in a further decrease of SV Hct in ischemic myocardium. Six open chest anesthetized dogs were studied. Plasma was labelled with /sup 59/FeCl siderophilin and RBC's with /sup 99/mTc to estimate SV Hct from myocardial biopsies. The LAD was occluded and cannulated for measurement of retrograde flow (arising presumably from proximal collaterals). The ischemic region was identified using the microsphere shadow technique. Collateral flow after LAD occlusion was 30 +- 12 ml/min 100g (x +- SE). Systemic Hct was 40 +- 1%. The Hct of blood from retrograde flow was 39 +- 1% (p = NS). Activity of /sup 59/FeCl and /sup 99/mTc in known quantities of blood were compared to myocardial biopsies to estimate SV Hct. Ischemic SV Hct was 23 +- 2% and non-ischemic SV Hct was 21 +- 1% (p = NS). We conclude that the size and branching pattern of coronary collaterals is such that plasma streaming in collaterals does not result in an additional decrease in SV Hct in ischemic myocardium.

Gumm, D.C.; Cooper, S.M.; Marcus, M.L.; Chilian, W.M.; Harrison, D.G.

1986-03-01

394

Numerical simulations of particle dynamics in a poststenotic blood vessel region within the scope of extracorporeal ultrasound stenosis treatment.  

PubMed

A numerical model was developed to predict the dynamics of a solid particle in a poststenotic blood vessel region. The flow through a 3D axisymmetric stenosis with 75% reduction in cross-section area was considered for inlet Reynolds numbers of 500 and 1000, which corresponds to typical values for the blood flow in human large arteries. Spherical particles were injected in the flow from the stenosis and tracked using the Discrete Phase Model (DPM) based on a Lagrangian approach. Within the scope of the development of ultrasound thrombolysis methods, the hydrodynamical forces predicted were used to evaluate the residence time of the particle and the minimal ultrasonic intensity required to keep it in the treatment region. For particle sizes larger than 400 ?m, the intensity required appeared to be compatible with extracorporeal therapeutic ultrasound. PMID:22119460

Dhahbi, M; Ben Chiekh, M; Gilles, B; Béra, J C; Jemni, A

2011-11-27

395

Effects of tissue outside of arterial blood vessels in pulse oximetry: a model of two-dimensional pulsation.  

PubMed

We describe a new model of pulse oximetry that addresses the disagreement between theoretical calibration curves based on Beer-Lambert's Law and test results based on human test subjects. Sources of this discrepancy include variability among human subjects, experimental conditions and the effect of optical radiation propagating in tissue surrounding arteries. Unlike the conventional model, our model considers the change in the relative proportion of light that does or does not pass through blood in pulsating vessels in addition to the change in the path length of optical radiation through the blood. Theoretical calibration curves based on this model agree with human test results and help to explain the variability between in vitro and in vivo test conditions. PMID:17960488

Yang, Shao; Batchelder, Paul B; Raley, Dena M

2007-10-25

396

Extending vaterite microviscometry to ex vivo blood vessels by serial calibration.  

PubMed

The endothelial glycocalyx layer is a ~2 µm thick glycosaminoglycan rich pericellular matrix expressed on the luminal surface of vascular endothelial cells, which has implications in vessel mechanics and mechanotransduction. Despite its role in vascular physiology, no direct measurement has of yet been made of vessel glycocalyx material properties. Vaterite microviscometry is a laser tweezers based microrheological method, which has been previously utilized to measure the viscosity of linear and complex fluids under flow. This form of microrheology has until now relied on complete recollection of the forward scattered light. Here we present a novel method to extend vaterite microviscometry to relatively thick samples. We validate our method and its assumptions and measure the apparent viscosity as a function of distance from the vascular endothelium. We observe a differential response in conditions designed to preserve the EGL in comparison to those designed to collapse it. PMID:22254166

Shreim, Samir G; Steward, Earl; Botvinick, Elliot L

2011-12-05

397

[Doppler ultrasound of fetal blood vessels--optimizing the diagnostic value by a combined diagram].  

PubMed

The dopplersonographic data of 1926 pregnant women in the 3. trimester of pregnancy was used to evaluate a graphic system for the analysis of A/B-ratio in fetal vessels (pulsed wave duplex system; descending aorta and umbilical arteries). The basis of the newly developed combination diagram were dopplersonographic standard values (single cut off and pregnancy duration related percentiles). One of the results was the fact, that the combined measurement and analysis of both fetal vessels increased the positive predictive value compared to single measurements. The value of dopplersonographic examinations in the aorta was slightly better than those in the umbilical arteries. The combined diagram showed a marked improvement in graphicness, especially in follow-up cases, and a partial improvement in statistical values. PMID:8328174

Rühle, W; Graf von Ballestrem, C L; Ertan, A K; Schmidt, W

398

Extending vaterite microviscometry to ex vivo blood vessels by serial calibration  

PubMed Central

The endothelial glycocalyx layer is a ~2 µm thick glycosaminoglycan rich pericellular matrix expressed on the luminal surface of vascular endothelial cells, which has implications in vessel mechanics and mechanotransduction. Despite its role in vascular physiology, no direct measurement has of yet been made of vessel glycocalyx material properties. Vaterite microviscometry is a laser tweezers based microrheological method, which has been previously utilized to measure the viscosity of linear and complex fluids under flow. This form of microrheology has until now relied on complete recollection of the forward scattered light. Here we present a novel method to extend vaterite microviscometry to relatively thick samples. We validate our method and its assumptions and measure the apparent viscosity as a function of distance from the vascular endothelium. We observe a differential response in conditions designed to preserve the EGL in comparison to those designed to collapse it.

Shreim, Samir G.; Steward, Earl; Botvinick, Elliot L.

2011-01-01

399

Abnormal blood vessel development and lethality in embryos lacking a single VEGF allele  

Microsoft Academic Search

THE endothelial cell-specific vascular endothelial growth factor (VEGF)1-5 and its cellular receptors Flt-1 (refs 6,7) and Flk-1 (refs 8,9) have been implicated in the formation of the embryonic vasculature. This is suggested by their colocalized expression during embryogenesis10,11 and the impaired vessel formation in Flk-1 (ref. 12) and Flt-1 (ref. 13) deficient embryos. However, because Flt-1 also binds placental growth

Peter Carmeliet; Valérie Ferreira; Georg Breier; Saskia Pollefeyt; Lena Kieckens; Marina Gertsenstein; Michaela Fahrig; Ann Vandenhoeck; Kendraprasad Harpal; Carmen Eberhardt; Cathérine Declercq; Judy Pawling; Lieve Moons; Désiré Collen; Werner Risau; Andras Nagy

1996-01-01

400

RGS5 expression is a quantitative measure of pericyte coverage of blood vessels  

Microsoft Academic Search

Pericytes play a key role in the process of vascular maturation and stabilization however, the current methods for quantifying\\u000a pericyte coverage of the neovasculature are laborious and subjective in nature. In this study, we have developed an objective,\\u000a sensitive, and high-throughput method for quantifying pericyte coverage of angiogenic vessels by analyzing the expression\\u000a of the pericyte-specific gene, the regulator of

Tracy S. Mitchell; John Bradley; Gregory S. Robinson; David T. Shima; Yin-Shan Ng

2008-01-01

401

In vivo and in vitro cytotoxicity of brown spider venom for blood vessel endothelial cells.  

PubMed

The effect of brown spider (Loxosceles intermedia) venom on endothelial cells was investigated in vivo and in vitro. Morphological and ultrastructural observations by light microscopy and transmission electron microscop