Sample records for blood vessel branching

  1. Branching Blood Vessels

    NSDL National Science Digital Library

    Mr. Jonathan Borne (Union Springs Academy)

    2000-08-01

    This activity explores some of the factors that affect blood flow in branching vessels and is designed for AP Biology, Anatomy & Physiology, and Physics. You may want to do this as activity as a series of labs or you can assign the problems to different groups. After conducting this lab myself, I suggest that you practice it yourself before doing it in class. Be sure that your tubing and funnel fit snugly. Also, make sure that your clamps and Y-connectors fit snugly with the tubing as well.

  2. 196 MATHEMATICS MAGAZINE Blood Vessel Branching: Beyond the

    E-print Network

    Adam, John A.

    arteries, veins, and capillaries that permit the flow of blood from the heart, around the body, and back and the peak blood flow because of the Math. Mag. 84 (2011) 196­207. doi:10.4169/math.mag.84.3.196. c). Cumulatively, this can modify the blood dynamics, as do the surface waves along the vessel walls, induced

  3. Histamine metabolism influences blood vessel branching in zebrafish reg6 mutants

    Microsoft Academic Search

    Cheng-chen Huang; Yih-Shyun E Cheng; John Yu

    2008-01-01

    Background  Vascular branching morphogenesis is responsible for the extension of blood vessels into growing tissues, a process crucial\\u000a for organogenesis. However, the genetic mechanism for vessel branching is largely unknown. Zebrafish reg6 is a temperature-sensitive mutation exhibiting defects in blood vessel branching which results in the formation of swollen\\u000a vessel lumina during capillary plexus formation.\\u000a \\u000a \\u000a \\u000a \\u000a Results  We performed a screening for chemical

  4. Blood Vessels

    NSDL National Science Digital Library

    Mrs. Hirschi

    2007-11-20

    Part of the circulatory system is composed of a series of tubes carries the vital elements and the wastes that keep us strong and healthy. Take a look at these amazing vessels and how they work together. Ever cut yourself on the toe? How about the finger? The ear? Ever get a bloody nose? How about a scrape on the knee? If these things have ever happened to you then you already know that blood vessels carry blood to EVERY part of the body. They start out ...

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

    PubMed Central

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

    2002-01-01

    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. PMID:12381667

  6. Tumor Blood Vessel Dynamics

    NASA Astrophysics Data System (ADS)

    Munn, Lance

    2009-11-01

    ``Normalization'' of tumor blood vessels has shown promise to improve the efficacy of chemotherapeutics. In theory, anti-angiogenic drugs targeting endothelial VEGF signaling can improve vessel network structure and function, enhancing the transport of subsequent cytotoxic drugs to cancer cells. In practice, the effects are unpredictable, with varying levels of success. The predominant effects of anti-VEGF therapies are decreased vessel leakiness (hydraulic conductivity), decreased vessel diameters and pruning of the immature vessel network. It is thought that each of these can influence perfusion of the vessel network, inducing flow in regions that were previously sluggish or stagnant. Unfortunately, when anti-VEGF therapies affect vessel structure and function, the changes are dynamic and overlapping in time, and it has been difficult to identify a consistent and predictable normalization ``window'' during which perfusion and subsequent drug delivery is optimal. This is largely due to the non-linearity in the system, and the inability to distinguish the effects of decreased vessel leakiness from those due to network structural changes in clinical trials or animal studies. We have developed a mathematical model to calculate blood flow in complex tumor networks imaged by two-photon microscopy. The model incorporates the necessary and sufficient components for addressing the problem of normalization of tumor vasculature: i) lattice-Boltzmann calculations of the full flow field within the vasculature and within the tissue, ii) diffusion and convection of soluble species such as oxygen or drugs within vessels and the tissue domain, iii) distinct and spatially-resolved vessel hydraulic conductivities and permeabilities for each species, iv) erythrocyte particles advecting in the flow and delivering oxygen with real oxygen release kinetics, v) shear stress-mediated vascular remodeling. This model, guided by multi-parameter intravital imaging of tumor vessel structure and function, provides a tool for identifying the structural and functional determinants of tumor vessel normalization.

  7. Blood Vessels in Allotransplantation.

    PubMed

    Abrahimi, P; Liu, R; Pober, J S

    2015-07-01

    Human vascularized allografts are perfused through blood vessels composed of cells (endothelium, pericytes, and smooth muscle cells) that remain largely of graft origin and are thus subject to host alloimmune responses. Graft vessels must be healthy to maintain homeostatic functions including control of perfusion, maintenance of permselectivity, prevention of thrombosis, and participation in immune surveillance. Vascular cell injury can cause dysfunction that interferes with these processes. Graft vascular cells can be activated by mediators of innate and adaptive immunity to participate in graft inflammation contributing to both ischemia/reperfusion injury and allograft rejection. Different forms of rejection may affect graft vessels in different ways, ranging from thrombosis and neutrophilic inflammation in hyperacute rejection, to endothelialitis/intimal arteritis and fibrinoid necrosis in acute cell-mediated or antibody-mediated rejection, respectively, and to diffuse luminal stenosis in chronic rejection. While some current therapies targeting the host immune system do affect graft vascular cells, direct targeting of the graft vasculature may create new opportunities for preventing allograft injury and loss. PMID:25807965

  8. Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol

    E-print Network

    Loughry, Jim

    Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol: 1. The blood vessels membrane is the peritoneum, the blood vessels are said to be retroperitoneal). In order to see the blood that supplies the stomach, liver and spleen with blood. This is the celiac artery. c. Just below where

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

    PubMed Central

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

    2013-01-01

    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

  10. Blood flow changes coincide with cellular rearrangements during blood vessel pruning in zebrafish embryos.

    PubMed

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

    2013-01-01

    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

  11. Cuff for Blood-Vessel Pressure Measurements

    NASA Technical Reports Server (NTRS)

    Shimizu, M.

    1982-01-01

    Pressure within blood vessel is measured by new cufflike device without penetration of vessel. Device continuously monitors blood pressure for up to 6 months or longer without harming vessel. Is especially useful for vessels smaller than 4 or 5 millimeters in diameter. Invasive methods damage vessel wall, disturb blood flow, and cause clotting. They do not always give reliable pressure measurements over prolonged periods.

  12. Disrupting tumour blood vessels

    Microsoft Academic Search

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

    2005-01-01

    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

  13. Optoacoustic imaging of blood vessels

    Microsoft Academic Search

    I. Patrikeev; H.-. Brecht; Y. Y. Petrov; I. Y. Petrova; D. S. Prough; R. O. Esenaliev

    2007-01-01

    Optoacoustic imaging, a novel noninvasive modality, combines the advantages of optical methods and the ultrasound technique. The optoacoustic technique is based on tissue irradiation with nanosecond laser pulses and detection of ultrasound waves generated due to thermo-elastic expansion. Using a modified Monte Carlo technique and solution of wave equation for velocity potential, we modeled optoacoustic signals from cylindrical blood vessels

  14. Exploring the Elasticity of Blood Vessels

    NSDL National Science Digital Library

    2000-07-01

    The two main blood vessels of the body are arteries and veins. The heart pumps blood out to the body by way of arteries with veins carrying the blood back to the heart. Blood within these vessels is under pressure. Students will explore the differences in elasticity and whether this in turn affects the pressure within these vessels. As an optional extension to this activity students will explore the effects of arteriosclerosis and blood clots on blood flow.

  15. Molecular control of endothelial cell behaviour during blood vessel morphogenesis

    Microsoft Academic Search

    Shane P. Herbert; Didier Y. R. Stainier

    2011-01-01

    The vertebrate vasculature forms an extensive branched network of blood vessels that supplies tissues with nutrients and oxygen. During vascular development, coordinated control of endothelial cell behaviour at the levels of cell migration, proliferation, polarity, differentiation and cell–cell communication is critical for functional blood vessel morphogenesis. Recent data uncover elaborate transcriptional, post-transcriptional and post-translational mechanisms that fine-tune key signalling pathways

  16. Retinal blood vessels extraction using probabilistic modelling.

    PubMed

    Kaba, Djibril; Wang, Chuang; Li, Yongmin; Salazar-Gonzalez, Ana; Liu, Xiaohui; Serag, Ahmed

    2014-01-01

    The analysis of retinal blood vessels plays an important role in detecting and treating retinal diseases. In this review, we present an automated method to segment blood vessels of fundus retinal image. The proposed method could be used to support a non-intrusive diagnosis in modern ophthalmology for early detection of retinal diseases, treatment evaluation or clinical study. This study combines the bias correction and an adaptive histogram equalisation to enhance the appearance of the blood vessels. Then the blood vessels are extracted using probabilistic modelling that is optimised by the expectation maximisation algorithm. The method is evaluated on fundus retinal images of STARE and DRIVE datasets. The experimental results are compared with some recently published methods of retinal blood vessels segmentation. The experimental results show that our method achieved the best overall performance and it is comparable to the performance of human experts. PMID:25825666

  17. Angiology: Diseases of the Blood Vessels

    Microsoft Academic Search

    Gabriel A. Adelmann

    \\u000a The heart is a modified blood vessel, embryologically, structurally (the endothelium, media, and serosa correspond to the endocardium, myocardium, and pericardium, respectively), and functionally (both the heart and the blood vessels are composed of an inner cavity for blood flow, and a wall with elastic and muscular\\u000a cells). Consequently, there is ample similarity between cardiac and vascular diseases.

  18. Tianma modulates blood vessel tonicity.

    PubMed

    Feng, Lin; Manavalan, Arulmani; Mishra, Manisha; Sze, Siu Kwan; Hu, Jiang-Miao; Heese, Klaus

    2012-01-01

    Tianma is a traditional Chinese medicine (TCM) often used for the treatment of hypertension and heart diseases. To elucidate the function of tianma at the molecular level, we investigated the effect of tianma on vascular functions and aortic protein metabolism. We found that long-term treatment with tianma (~2.5g/kg/day for three months) in one-year-old rats could enhance acetylcholine (ACh)-induced vasorelaxation in endothelium-intact thoracic aortic rings against both KCl (80 mM)- and phenylephrine (PE)-induced contraction. By using the iTRAQ (isobaric tag for relative and absolute quantification) technique, we confirmed from the functional data at the proteome level that tianma treatment down-regulated the expressions of contractile proteins (e.g. Acta2) and other related structural proteins (e.g. desmin), and up-regulated the expressions of extracellular matrix (ECM) glycoproteins (e.g. Fbln5) and anti-thrombotic proteins (e.g. Anxa2) in aortic tissue. By inductive reasoning, tianma could perform its vasodilatory effect not only by inhibiting vascular smooth muscle contraction, but also by enhancing blood vessel elasticity and stabilizing the arterial structure. Thus, tianma might become a novel therapeutic herbal medicine for cardiovascular diseases by regulating the aortic proteome metabolism. PMID:22787517

  19. [Blood vessel access, skill and tricks].

    PubMed

    Rodríguez Sánchez, María José

    2008-03-01

    From a personal viewpoint, the author explains diverse "tricks" and skills which can be used when facing various emergency situation. In this case, the author deals with means of applying blood vessel access. PMID:18444367

  20. Automated computational framework of blood vessel quantification in chick chorioallantoic membrane angiogenesis.

    PubMed

    Shi, Peng; Hong, Jinsheng; Huang, Yue; Zhang, Zhenhuan; Zhang, Mei; Zhang, Lurong

    2014-01-01

    Chick chorioallantoic membrane (CAM) angiogenesis assay has been widely used for finding drugs targeting new blood vessel development in cancer research. In addition to the setup materials and protocols, laboratory findings depend on the quantification and analysis of microscopic blood vessel images. However, it is still a challenging problem because of the high complexity of blood vessel branching structures. We applied preprocessing on CAM microscopic images by keeping the integrity of minor branches in the vessel structure. We then proposed an efficient way to automatically extract blood vessel centerlines based on vector tracing starting from detected seed points. Finally, all branches were coded to construct an abstract model of the branching structure, which enabled more accurate modeling for in-depth analysis. The framework was applied in quantifying Icaritin (ICT) inhibition effects on angiogenesis in a CAM model. Experimental results showed the high accuracy in blood vessel quantification and modeling compared with semimanual measurements. Meanwhile, a set of blood vessel growth indicators were extracted to provide fully automated analysis for angiogenesis assays. Further analysis proved that ICT took effect in a dose-dependent manner which could be applied in suppressing tumor blood vessel growth. PMID:25277148

  1. Trends in tissue engineering for blood vessels.

    PubMed

    Nemeno-Guanzon, Judee Grace; Lee, Soojung; Berg, Johan Robert; Jo, Yong Hwa; Yeo, Jee Eun; Nam, Bo Mi; Koh, Yong-Gon; Lee, Jeong Ik

    2012-01-01

    Over the years, cardiovascular diseases continue to increase and affect not only human health but also the economic stability worldwide. The advancement in tissue engineering is contributing a lot in dealing with this immediate need of alleviating human health. Blood vessel diseases are considered as major cardiovascular health problems. Although blood vessel transplantation is the most convenient treatment, it has been delimited due to scarcity of donors and the patient's conditions. However, tissue-engineered blood vessels are promising alternatives as mode of treatment for blood vessel defects. The purpose of this paper is to show the importance of the advancement on biofabrication technology for treatment of soft tissue defects particularly for vascular tissues. This will also provide an overview and update on the current status of tissue reconstruction especially from autologous stem cells, scaffolds, and scaffold-free cellular transplantable constructs. The discussion of this paper will be focused on the historical view of cardiovascular tissue engineering and stem cell biology. The representative studies featured in this paper are limited within the last decade in order to trace the trend and evolution of techniques for blood vessel tissue engineering. PMID:23251085

  2. The effects of blood vessels on electrocorticography

    NASA Astrophysics Data System (ADS)

    Bleichner, M. G.; Vansteensel, M. J.; Huiskamp, G. M.; Hermes, D.; Aarnoutse, E. J.; Ferrier, C. H.; Ramsey, N. F.

    2011-08-01

    Electrocorticography, primarily used in a clinical context, is becoming increasingly important for fundamental neuroscientific research, as well as for brain-computer interfaces. Recordings from these implanted electrodes have a number of advantages over non-invasive recordings in terms of band width, spatial resolution, smaller vulnerability to artifacts and overall signal quality. However, an unresolved issue is that signals vary greatly across electrodes. Here, we examine the effect of blood vessels lying between an electrode and the cortex on signals recorded from subdural grid electrodes. Blood vessels of different sizes cover extensive parts of the cortex causing variations in the electrode-cortex connection across grids. The power spectral density of electrodes located on the cortex and electrodes located on blood vessels obtained from eight epilepsy patients is compared. We find that blood vessels affect the power spectral density of the recorded signal in a frequency-band-specific way, in that frequencies between 30 and 70 Hz are attenuated the most. Here, the signal is attenuated on average by 30-40% compared to electrodes directly on the cortex. For lower frequencies this attenuation effect is less pronounced. We conclude that blood vessels influence the signal properties in a non-uniform manner.

  3. Injuries to major blood vessels during endoscopy

    Microsoft Academic Search

    Richard M. Soderstrom

    1997-01-01

    Major blood vessel injury is a true emergency during endoscopic procedures. Too often, fear of litigation quashes the opportunity to assess the cause and learn from the experience of others. Frequently, only through a medicolegal review can such events be evaluated. A review of 47 such cases highlighted several key lessons. Proper technique for inserting the Veress needle, laparoscopic cannula,

  4. Blackworms, Blood Vessel Pulsations and Drug Effects.

    ERIC Educational Resources Information Center

    Lesiuk, Nalena M.; Drewes, Charles D.

    1999-01-01

    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…

  5. Unsteady Flow in Stenotic Blood Vessels

    Microsoft Academic Search

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

    2003-01-01

    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

  6. Automated measurement of retinal blood vessel tortuosity

    NASA Astrophysics Data System (ADS)

    Joshi, Vinayak; Reinhardt, Joseph M.; Abramoff, Michael D.

    2010-03-01

    Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. We developed a new quantitative metric for vascular tortuosity, based on the vessel's angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). In comparison to other published methods this method can estimate appropriate TI for vessels with constant curvature sign and vessels with equal arc to chord ratios, as well. We applied this method to a dataset of 15 digital fundus images of 8 patients with Facioscapulohumeral muscular dystrophy (FSHD), and to the other publically available dataset of 60 fundus images of normal cases and patients with hypertensive retinopathy, of which the arterial and venous tortuosities have also been graded by masked experts (ophthalmologists). The method produced exactly the same rank-ordered list of vessel tortuosity (TI) values as obtained by averaging the tortuosity grading given by 3 ophthalmologists for FSHD dataset and a list of TI values with high ranking correlation with the ophthalmologist's grading for the other dataset. Our results show that TI has potential to detect and evaluate abnormal retinal vascular structure in early diagnosis and prognosis of retinopathies.

  7. Zinc oxide nanoflowers make new blood vessels

    NASA Astrophysics Data System (ADS)

    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

    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

  8. The Degree of Nonlinearity and Anisotropy of Blood Vessel Elasticity

    Microsoft Academic Search

    J. Zhou; Y. C. Fung

    1997-01-01

    Blood vessel elasticity is important to physiology and clinical problems involving surgery, angioplasty, tissue remodeling, and tissue engineering. Nonlinearity in blood vessel elasticity in vivo is important to the formation of solitons in arterial pulse waves. It is well known that the stress-strain relationship of the blood vessel is nonlinear in general, but a controversy exists on how nonlinear it

  9. RETINAL BLOOD VESSEL SEGMENTATION USING GEODESIC VOTING METHODS Youssef Rouchdy

    E-print Network

    Cohen, Laurent

    RETINAL BLOOD VESSEL SEGMENTATION USING GEODESIC VOTING METHODS Youssef Rouchdy and Laurent D to segment retinal blood vessels are presented. Many authors have used minimal cost paths, or similarly on the use of a set of such geodesic paths to extract retinal blood vessels, using minimal interaction

  10. Image Segmentation Methods for Detecting Blood Vessels in Angiography

    E-print Network

    Chung, Albert C. S.

    Image Segmentation Methods for Detecting Blood Vessels in Angiography Albert C. S. Chung Lo Kwee-assisted detection and segmentation of blood vessels in angiography are crucial for endovascular treat- ments--Segmentation of Blood Vessels, Feature Detection, Statistical Segmentation, Active Contour Model, Angiography I

  11. Modeling Torsion of Blood Vessels in Surgical Simulation and Planning

    E-print Network

    Leow, Wee Kheng

    Modeling Torsion of Blood Vessels in Surgical Simulation and Planning Hao LI a,1 , Wee Kheng LEOW a hybrid approach for modeling torsion of blood vessels that undergo deformation and joining. The proposed model takes 3D mesh of the blood vessel as input. It first fits a generalized cylinder to extract

  12. Platelets, endothelium and blood vessel wall

    Microsoft Academic Search

    P. M. Vanhoutte

    1988-01-01

    Summary Aggregating platelets cause contraction of vascular smooth muscle, because they release serotonin and thromboxane A2. If the platelets aggregate in a blood vessel with intact intima, the platelet-products cause endothelium-dependent relaxation of the underlying smooth muscle. Hence, the presence of an intact intima considerably reduces the vasospastic response to platelet-aggregation. The major platelet products which trigger endothelium-dependent relaxations are

  13. Method and device for supporting blood vessels during anastomosis

    DOEpatents

    Doss, J.D.

    1985-05-20

    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.

  14. Photoacoustic removal of occlusions from blood vessels

    DOEpatents

    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

    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.

  15. Quantitative assessment of angiogenesis, perfused blood vessels and endothelial tip cells in the postnatal mouse brain.

    PubMed

    Wälchli, Thomas; Mateos, José María; Weinman, Oliver; Babic, Daniela; Regli, Luca; Hoerstrup, Simon P; Gerhardt, Holger; Schwab, Martin E; Vogel, Johannes

    2015-01-01

    During development and in various diseases of the CNS, new blood vessel formation starts with endothelial tip cell selection and vascular sprout migration, followed by the establishment of functional, perfused blood vessels. Here we describe a method that allows the assessment of these distinct angiogenic steps together with antibody-based protein detection in the postnatal mouse brain. Intravascular and perivascular markers such as Evans blue (EB), isolectin B4 (IB4) or laminin (LN) are used alongside simultaneous immunofluorescence on the same sections. By using confocal laser-scanning microscopy and stereological methods for analysis, detailed quantification of the 3D postnatal brain vasculature for perfused and nonperfused vessels (e.g., vascular volume fraction, vessel length and number, number of branch points and perfusion status of the newly formed vessels) and characterization of sprouting activity (e.g., endothelial tip cell density, filopodia number) can be obtained. The entire protocol, from mouse perfusion to vessel analysis, takes ?10 d. PMID:25502884

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

    PubMed

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

    2012-01-01

    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

  17. An approach to localize the retinal blood vessels using bit planes and centerline detection.

    PubMed

    Fraz, M M; Barman, S A; Remagnino, P; Hoppe, A; Basit, A; Uyyanonvara, B; Rudnicka, A R; Owen, C G

    2012-11-01

    The change in morphology, diameter, branching pattern or tortuosity of retinal blood vessels is an important indicator of various clinical disorders of the eye and the body. This paper reports an automated method for segmentation of blood vessels in retinal images. A unique combination of techniques for vessel centerlines detection and morphological bit plane slicing is presented to extract the blood vessel tree from the retinal images. The centerlines are extracted by using the first order derivative of a Gaussian filter in four orientations and then evaluation of derivative signs and average derivative values is performed. Mathematical morphology has emerged as a proficient technique for quantifying the blood vessels in the retina. The shape and orientation map of blood vessels is obtained by applying a multidirectional morphological top-hat operator with a linear structuring element followed by bit plane slicing of the vessel enhanced grayscale image. The centerlines are combined with these maps to obtain the segmented vessel tree. The methodology is tested on three publicly available databases DRIVE, STARE and MESSIDOR. The results demonstrate that the performance of the proposed algorithm is comparable with state of the art techniques in terms of accuracy, sensitivity and specificity. PMID:21963241

  18. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    SciTech Connect

    Akabani, G.; Poston, J.W. Sr. (Texas A M Univ., College Station (USA))

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No penetration of the radionuclide into the blood vessel was assumed nor was cross fire between the vessel assumed. The results are useful in assessing the dose to blood and blood vessel walls for different nuclear medicine procedures.

  19. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    SciTech Connect

    Akabani, G. (Pacific Northwest Lab., Richland, WA (USA)); Poston, J.W. (Texas A and M Univ., College Station, TX (USA). Dept. of Nuclear Engineering)

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs.

  20. Avian Blood-Vessel Formation in Space

    NASA Technical Reports Server (NTRS)

    Lelkes, Peter I.

    1999-01-01

    Based on previous studies, we hypothesized that the developmental anomalies observed in the past might be related to or caused by delayed or improper vascular development. The objective of our research is to test the hypothesis that exposure to microgravity during space flight cause delayed or improper vascular development during embryogenesis. The effects of microgravity on the time course and extent of avian blood-vessel formation are assessed using two models, one for angiogenesis and one for vasculogenesis. The methodological approach is dictated by the constraints of the tissue preservation method used in space. Thus, both in the chorioallantoic membrane (CAM) and in the adrenal, we will evaluate microscopically the vascular architecture and immunostain endothelial cells with specific antibodies (anti- vWF and QH1). The extent of ECM protein deposition will be assessed by immunohistochemistry and correlated with the degree of vascularization, using computer-based image analysis. Also, the cellular source for ECM proteins will be assessed by in situ hybridization.

  1. Optical model of the blood in large retinal vessels.

    PubMed

    Denninghoff, K R; Smith, M H

    2000-10-01

    Several optical techniques that investigate blood contained within the retinal vessels are available or under development. We present a mechanical model that simulates the optical properties of the eye, the retinal vessels, and the ocular fundus. A micropipette is chosen as the retinal vessel model, and a mechanical housing is constructed to simulate the eyeball. Spectralon is used to simulate the retinal layers. Filling the eye with fluid index matched to the glass pipette eliminates reflection and refraction effects from the pipette. An apparatus is constructed and used to set the oxygen, nitrogen, and carbon dioxide concentrations in whole human blood. These whole blood samples are pumped through the pipette at 34 microL/min. Measurements made in the model eye closely resemble measurements made in the human eye. This apparatus is useful for developing the science and testing the systems that optically investigate blood and blood flow in the large retinal vessels. PMID:11092424

  2. Optical model of the blood in large retinal vessels

    NASA Astrophysics Data System (ADS)

    Denninghoff, Kurt R.; Smith, Matthew H.

    2000-10-01

    Several optical techniques that investigate blood contained within the retinal vessels are available or under development. We present a mechanical model that simulates the optical properties of the eye, the retinal vessels, and the ocular fundus. A micropipette is chosen as the retinal vessel model, and a mechanical housing is constructed to simulate the eyeball. Spectralon is used to simulate the retinal layers. Filling the eye with fluid index matched to the glass pipette eliminates reflection and refraction effects from the pipette. An apparatus is constructed and used to set the oxygen, nitrogen, and carbon dioxide concentrations in whole human blood. These whole blood samples are pumped through the pipette at 34 (mu) L/min. Measurements made in the model eye closely resemble measurements made in the human eye. This apparatus is useful for developing the science and testing the systems that optically investigate blood and blood flow in the large retinal vessels.

  3. Noninvasive Visualization of Human Capillary Vessel Blood Flow

    NASA Astrophysics Data System (ADS)

    Watanabe, Masao

    2005-11-01

    Human blood flows are highly susceptible to physical and health conditions. Hence quantitative evaluation of Blood flow is a useful parameter in the physical check up of individuals. However, the most convenient method is taking a blood sample, which can only examine ex vivo Blood condition. We turn our attention to the observation of the capillary loops of blood vessels in the finger skin nail fold, in which blood flow can be easily visualized without using complicated specialized tools other than capillaroscopy. We modified both the spatial and temporal resolution in capillaroscopy. A deep-focus high magnification zoom lens and a high speed video camera of 1000 fps allowed us to observe the motion of red blood cells, white blood cells and plasmas. Quantitative analysis of blood flow allowed us to observe the motion of red blood cells in capillary vessels with a diameter of about 10 micro meters. We discuss the quantitative evaluation of blood flow velocity in artery capillary vessels. We also conducted shape analysis of the capillary vessel, by using the level set method. By analyzing the obtained level set function, quantitative evaluation of the capillary blood shape, such as characteristic diameters and curvatures, are carried out.

  4. Large Blood Vessels 1.1 Introduction --The Cardiovascular System

    E-print Network

    Luo, Xiaoyu

    Chapter 1 Large Blood Vessels 1.1 Introduction -- The Cardiovascular System The heart is a pump that circulates blood to the lungs for oxygenation (pul- monary circulation) and then throughout the systemic arterial system with a total cycle time of about one minute. From the left ventricle of the heart, blood

  5. Recovery of testicular blood flow following ligation of testicular vessels

    SciTech Connect

    Pascual, J.A.; Villanueva-Meyer, J.; Salido, E.; Ehrlich, R.M.; Mena, I.; Rajfer, J.

    1989-08-01

    To determine whether initial ligation of the testicular vessels of the high undescended testis followed by a delayed secondary orchiopexy is a viable alternative to the classical Fowler-Stephens procedure, a series of preliminary experiments were conducted in the rat in which testicular blood flow was measured by the 133-xenon washout technique before, and 1 hour and 30 days after ligation of the vessels. In addition, testicular histology, and testis and sex-accessory tissue weights were measured in 6 control, 6 sham operated and 6 testicular vessel ligated rats 54 days after vessel ligation. The data demonstrate that ligation and division of the testicular blood vessels produce an 80 per cent decrease in testicular blood flow 1 hour after ligation of the vessels. However, 30 days later testis blood flow returns to the control and pre-treatment value. There were no significant changes in testis or sex-accessory tissue weights 54 days after vessel ligation. Histologically, 4 of the surgically operated testes demonstrated necrosis of less than 25 per cent of the seminiferous tubules while 1 testis demonstrated more than 75 per cent necrosis. The rest of the tubules in all 6 testes demonstrated normal spermatogenesis. From this study we conclude that initial testicular vessel ligation produces an immediate decrease in testicular blood flow but with time the collateral vessels are able to compensate and return the testis blood flow to its normal pre-treatment value. These preliminary observations lend support for the concept that initial ligation of the testicular vessels followed by a delayed secondary orchiopexy in patients with a high undescended testis may be a possible alternative to the classical Fowler-Stephens approach.

  6. Development of blood vessel searching system for HMS

    NASA Astrophysics Data System (ADS)

    Kandani, Hirofumi; Uenoya, Toshiyuki; Uetsuji, Yasutomo; Nakamachi, Eiji

    2008-08-01

    In this study, we develop a new 3D miniature blood vessel searching system by using near-infrared LED light, a CMOS camera module with an image processing unit for a health monitoring system (HMS), a drug delivery system (DDS) which requires very high performance for automatic micro blood volume extraction and automatic blood examination. Our objective is to fabricate a highly reliable micro detection system by utilizing image capturing, image processing, and micro blood extraction devices. For the searching system to determine 3D blood vessel location, we employ the stereo method. The stereo method is a common photogrammetric method. It employs the optical path principle to detect 3D location of the disparity between two cameras. The principle for blood vessel visualization is derived from the ratio of hemoglobin's absorption of the near-infrared LED light. To get a high quality blood vessel image, we adopted an LED, with peak a wavelength of 940nm. The LED is set on the dorsal side of the finger and it irradiates the human finger. A blood vessel image is captured by a CMOS camera module, which is set below the palmer side of the finger. 2D blood vessel location can be detected by the luminance distribution of a one pixel line. To examine the accuracy of our detecting system, we carried out experiments using finger phantoms with blood vessel diameters of 0.5, 0.75, 1.0mm, at the depths of 0.5 ~ 2.0 mm from the phantom's surface. The experimental results of the estimated depth obtained by our detecting system shows good agreements with the given depths, and the viability of this system is confirmed.

  7. Computer Analysis of Eye Blood-Vessel Images

    NASA Technical Reports Server (NTRS)

    Wall, R. J.; White, B. S.

    1984-01-01

    Technique rapidly diagnoses diabetes mellitus. Photographs of "whites" of patients' eyes scanned by computerized image analyzer programmed to quantify density of small blood vessels in conjuctiva. Comparison with data base of known normal and diabetic patients facilitates rapid diagnosis.

  8. Analysis of Blood Flow in a Partially Blocked Bifurcated Blood Vessel

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

    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.

  9. Blood Vessel Adaptation with Fluctuations in Capillary Flow Distribution

    PubMed Central

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

    2012-01-01

    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. PMID:23029014

  10. What Determines Blood Vessel Structure? Genetic Prespecification vs. Hemodynamics

    NSDL National Science Digital Library

    Elizabeth A. V. Jones (College de France)

    2006-10-01

    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.

  11. A systems biology view of blood vessel growth and remodelling

    PubMed Central

    Logsdon, Elizabeth A; Finley, Stacey D; Popel, Aleksander S; Gabhann, Feilim Mac

    2014-01-01

    Blood travels throughout the body in an extensive network of vessels – arteries, veins and capillaries. This vascular network is not static, but instead dynamically remodels in response to stimuli from cells in the nearby tissue. In particular, the smallest vessels – arterioles, venules and capillaries – can be extended, expanded or pruned, in response to exercise, ischaemic events, pharmacological interventions, or other physiological and pathophysiological events. In this review, we describe the multi-step morphogenic process of angiogenesis – the sprouting of new blood vessels – and the stability of vascular networks in vivo. In particular, we review the known interactions between endothelial cells and the various blood cells and plasma components they convey. We describe progress that has been made in applying computational modelling, quantitative biology and high-throughput experimentation to the angiogenesis process. PMID:24237862

  12. Simple Analysis of the Pulse Wave for Blood Vessel Evaluation

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    A pulse wave is considered to be a good indicator to evaluate the viscoelastic properties of blood vessels. The wave is composed of an incident wave and a reflected wave. The evaluation of blood vessels may be possible from the analysis of this reflected wave, because the reflected wave propagates to the peripheral artery. We propose a simple method of estimating the reflected wave from the pulse wave observed at common carotid artery, making use of a commercial piezoelectric transducer. First, we estimate the incident wave from the observed blood flow velocity. Then, the reflected wave is estimated by subtracting the incident wave from the observed pulse wave. The amplitudes of the reflected wave obtained in senior subjects were larger than those of junior subjects. This result is in good agreement with the common point of view about the vessel wall, that the attenuation during pulse wave propagation is usually small in elderly people.

  13. Crosstalk between the developing pancreas and its blood vessels: an evolving dialogue

    PubMed Central

    Villasenor, Alethia; Cleaver, Ondine

    2015-01-01

    Growth and development of embryonic organs goes hand in hand with development of the vascular system. Blood vessels have been known for centuries to supply nutrients and oxygen to all cell types in an organism, however, they have more recently been shown to provide specific cues required for the formation and functionality of a number of tissues. Here, we review the role of blood vessels during pancreas formation, from early specification of the initial pancreatic bud, to its growth and maturation. The overarching theme that emerges from the many studies carried out in the past decade is that the vasculature likely plays diverse and changing roles during pancreas organogenesis. Blood vessels are required for endocrine specification at the onset of pancreatic budding, while only a few days later, blood vessels suppress pancreatic branching and exocrine differentiation. In this review, we summarize our understanding to date about the crosstalk between the pancreas and its vasculature, and we provide a perspective on the promises and challenges of the field. PMID:22728668

  14. Vulnerability of Xylem Vessels to Cavitation in Sugar Maple. Scaling from Individual Vessels to Whole Branches1

    PubMed Central

    Melcher, Peter J.; Zwieniecki, Maciej A.; Holbrook, N. Michele

    2003-01-01

    The relation between xylem vessel age and vulnerability to cavitation of sugar maple (Acer saccharum Marsh.) was quantified by measuring the pressure required to force air across bordered pit membranes separating individual xylem vessels. We found that the bordered pit membranes of vessels located in current year xylem could withstand greater applied gas pressures (3.8 MPa) compared with bordered pit membranes in vessels located in older annular rings (2.0 MPa). A longitudinal transect along 6-year-old branches indicated that the pressure required to push gas across bordered pit membranes of current year xylem did not vary with distance from the growing tip. To understand the contribution of age-related changes in vulnerability to the overall resistance to cavitation, we combined data on the pressure thresholds of individual xylem vessels with measurements of the relative flow rate through each annual ring. The annual ring of the current year contributed only 16% of the total flow measured on 10-cm-long segments cut from 6-year-old branches, but it contributed more than 70% of the total flow when measured through 6-year-old branches to the point of leaf attachment. The vulnerability curve calculated using relative flow rates measured on branch segments were similar to vulnerability curves measured on 6-year-old branches (pressure that reduces hydraulic conductance by 50% = 1.6–2.4 MPa), whereas the vulnerability curve calculated using relative flow rates measured on 6-year-old branches were similar to ones measured on the extension growth of the current year (pressure that reduces hydraulic conductance by 50% = 3.8 MPa). These data suggest that, in sugar maple, the xylem of the current year can withstand larger xylem tensions than older wood and dominates water delivery to leaves. PMID:12692336

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

    Microsoft Academic Search

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

    1991-01-01

    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

  16. Acrolein generation stimulates hypercontraction in isolated human blood vessels

    SciTech Connect

    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

    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.

  17. The deletion of Math5 disrupts retinal blood vessel and glial development in mice.

    PubMed

    Edwards, Malia M; McLeod, D Scott; Li, Renzhong; Grebe, Rhonda; Bhutto, Imran; Mu, Xiuqian; Lutty, Gerard A

    2012-03-01

    Retinal vascular development is a complex process that is not yet fully understood. The majority of research in this area has focused on astrocytes and the template they form in the inner retina, which precedes endothelial cells in the mouse retina. In humans and dogs, however, astrocyte migration follows behind development of blood vessels, suggesting that other cell types may guide this process. One such cell type is the ganglion cell, which differentiates before blood vessel formation and lies adjacent to the primary retinal vascular plexus. The present study investigated the potential role played by ganglion cells in vascular development using Math5(-/-) mice. It has previously been reported that Math5 regulates the differentiation of ganglion cells and Math5(-/-) mice have a 95% reduction in these cells. The development of blood vessels and glia was investigated using Griffonia simplicifolia isolectin B4 labeling and GFAP immunohistochemistry, respectively. JB-4 analysis demonstrated that the hyaloid vessels arose from choriovitreal vessels adjacent to the optic nerve area. As previously reported, Math5(-/-) mice had a rudimentary optic nerve. The primary retinal vessels did not develop post-natally in the Math5(-/-) mice, however, branches of the hyaloid vasculature eventually dove into the retina and formed the inner retinal capillary networks. An astrocyte template only formed in some areas of the Math5(-/-) retina. In addition, GFAP(+) Müller cells were seen throughout the retina that had long processes wrapped around the hyaloid vessels. Transmission electron microscopy confirmed Müller cell abnormalities and revealed disruptions in the inner limiting membrane. The present data demonstrates that the loss of ganglion cells in the Math5(-/-) mice is associated with a lack of retinal vascular development. PMID:22200487

  18. Shear forces and blood vessel radii in the cardiovascular system

    Microsoft Academic Search

    M. ZAMIR

    1977-01-01

    A B S TR A C T What mathematical or physiological principles govern the radii of blood vessels in the cardiovascular system and by what mechanisms are these principles implemented? This question is studied in the contexts of fluid dynamics and physiology of the cardiovascular system, and a possible answer is examined in the light of empirical data.

  19. Gene Expression Analysis in Human Breast Cancer Associated Blood Vessels

    PubMed Central

    Jones, Dylan T.; Lechertier, Tanguy; Mitter, Richard; Herbert, John M. J.; Bicknell, Roy; Jones, J. Louise; Li, Ji-Liang; Buffa, Francesca; Harris, Adrian L.; Hodivala-Dilke, Kairbaan

    2012-01-01

    Angiogenesis is essential for solid tumour growth, whilst the molecular profiles of tumour blood vessels have been reported to be different between cancer types. Although presently available anti-angiogenic strategies are providing some promise for the treatment of some cancers it is perhaps not surprisingly that, none of the anti-angiogenic agents available work on all tumours. Thus, the discovery of novel anti-angiogenic targets, relevant to individual cancer types, is required. Using Affymetrix microarray analysis of laser-captured, CD31-positive blood vessels we have identified 63 genes that are upregulated significantly (5–72 fold) in angiogenic blood vessels associated with human invasive ductal carcinoma (IDC) of the breast as compared with blood vessels in normal human breast. We tested the angiogenic capacity of a subset of these genes. Genes were selected based on either their known cellular functions, their enriched expression in endothelial cells and/or their sensitivity to anti-VEGF treatment; all features implicating their involvement in angiogenesis. For example, RRM2, a ribonucleotide reductase involved in DNA synthesis, was upregulated 32-fold in IDC-associated blood vessels; ATF1, a nuclear activating transcription factor involved in cellular growth and survival was upregulated 23-fold in IDC-associated blood vessels and HEX-B, a hexosaminidase involved in the breakdown of GM2 gangliosides, was upregulated 8-fold in IDC-associated blood vessels. Furthermore, in silico analysis confirmed that AFT1 and HEX-B also were enriched in endothelial cells when compared with non-endothelial cells. None of these genes have been reported previously to be involved in neovascularisation. However, our data establish that siRNA depletion of Rrm2, Atf1 or Hex-B had significant anti-angiogenic effects in VEGF-stimulated ex vivo mouse aortic ring assays. Overall, our results provide proof-of-principle that our approach can identify a cohort of potentially novel anti-angiogenic targets that are likley to be, but not exclusivley, relevant to breast cancer. PMID:23056178

  20. Enhanced Cytomegalovirus Infection in Atherosclerotic Human Blood Vessels

    PubMed Central

    Nerheim, Pamela L.; Meier, Jeffery L.; Vasef, Mohammad A.; Li, Wei-Gen; Hu, Ling; Rice, James B.; Gavrila, Daniel; Richenbacher, Wayne E.; Weintraub, Neal L.

    2004-01-01

    Human cytomegalovirus (CMV) is a possible co-factor in atherogenesis and vascular occlusion, but its ability to actively infect medium and large blood vessels is unclear. A vascular explant model was adapted to investigate CMV infection in human coronary artery, internal mammary artery (IMA), and saphenous vein (SV). Vascular explants were inoculated with CMV Towne or low-passage clinical isolate and examined in situ for CMV cytopathic effect and immediate-early and early antigens, as indicators of active infection. At 5 to 7 days after inoculation, we found that CMV Towne actively infected eight of eight different atherosclerotic blood vessel explants (coronary artery, n = 4; SV and IMA grafts, n = 4), whereas it only infected 2 of 14 nonatherosclerotic blood vessel explants (SV, n = 10; IMA, n = 4) (P = 0.001). The CMV clinical isolate actively infected none of six sets of nonatherosclerotic SV explants at 5 to 7 days after inoculation. The active CMV infections involved adventitial and, less frequently, intimal cells. A small subset of infected cells in atherosclerotic tissue expresses the endothelial cell marker CD31. Smooth muscle cells residing in both atherosclerotic and nonatherosclerotic blood vessels were free of active CMV infections even after all vascular tissue layers were exposed to the virus. In contrast, active CMV Towne infection was evident at 2 days after inoculation in smooth muscle cells and endothelial cells previously isolated from the SV tissues. We conclude that active CMV infection is enhanced in atherosclerotic blood vessels compared to atherosclerosis-free vascular equivalents, and this viral activity is restricted to subpopulations of intimal and adventitial cells. PMID:14742264

  1. Interest of ICG blood clearance monitoring for reproducible 810-nm diode laser coagulation of blood vessels

    NASA Astrophysics Data System (ADS)

    Desmettre, Thomas; Soulie-Begu, Sylvie; Devoisselle, Jean-Marie; Mordon, Serge R.

    1999-02-01

    Purpose: To evaluate a method of control of diode laser fluence leading to a reproducible ICG-enhanced selective photocoagulation of blood vessels. This method would use the chromophore clearance, i.e. ICG blood concentration decay to adapt the laser fluence. Materials and Methods: A skin flap window was used on hamsters. After a 15 mg/kg ICG solution injection, photocoagulation of vessels were performed. Results: Selective photocoagulation of blood vessels was obtained only during the first 10 minutes. The fluence required to obtain a selective photocoagulation of vessels (F) was modelized using a one compartment phamacokinetic equation: F equals Of(1-e-t/(tau )). The best fit was obtained for a time constant (tau) equals 4.8 min and Of equals 300 J/cm2 (correlation coefficient r2 equals 0.996). During the first 10 minutes, the fluence required for selective photocoagulation of vessels was increased by a factor 4.5. Conclusion: Fluence required for a selective photocoagulation of vessels was correlated to ICG blood concentration decay. The time constant was equivalent to ICG half-life time in human blood. These results demonstrate that diode laser ICG-enhanced photocoagulation can be controlled by monitoring the ICG blood clearance.

  2. The Influence of Larger Subcutaneous Blood Vessels on Pulse Oximetry

    Microsoft Academic Search

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

    2004-01-01

    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

  3. Gross anatomy of the cardiac blood vessels in the North American beaver (Castor canadensis).

    PubMed

    Bisaillon, A

    1981-01-01

    The cardiac arteries and veins are described in the North American beaver (Castor canadensis) following the injection of the vessels of 15 hearts with either latex, vinyl plastic or barium sulfate. The left coronary artery gives off the typical circumflex and paraconal interventricular branches which supply the left atrium and ventricle and part of the right ventricle and interventricular septum. The right coronary artery vascularizes the right atrium and ventricule and by means of its subsinuosal interventricular branch, part of the left ventricle and interventricular septum. The paraconal interventricular branch of the left coronary artery lies within the myocardium and is not visible on the surface of the heart. There are no intercoronary anastomoses between the right and left vessels. The major cardiac veins open into the terminal end of the left cranial vena cava. Unlike the arteries, there are venous anastomoses interconnecting the great cardiac vein and the middle cardiac vein. It is concluded that the cardiac blood vessels in Castor canadensis are typically mammalian and resemble those of both land and aquatic mammals. PMID:7305001

  4. Unintentional Injection of Soft Tissue Filler into Blood Vessels in the Face: FDA Safety Communication

    MedlinePLUS

    ... into Blood Vessels in the Face: FDA Safety Communication Date Issued: May 28, 2015 Audiences: Health care ... blood vessels, consistent with the recommendations in this communication, so that both health care providers and patients ...

  5. Dimensional analysis of blood vessel images in real time

    NASA Astrophysics Data System (ADS)

    Smith, Peter R.; Eustaquio-Martin, Almudena; Thomason, Harry; Bennett, M.; Thurston, H.

    1996-01-01

    The physiology and pathology of dissected blood vessels are studied by perfusion myography combined with video microscopy. Images of the vessels are formed under diffuse white light illumination and contrast is achieved by differential absorption with respect to the vessel wall. To obtain the vessel dimensional information in quasi real time an edge-tracking algorithm is used, allowing the edges to be found by applying common image processing tools to a very small number of pixels rather than the whole image. Employing a low order optical model of the light transmission properties of vessels with circular cross section, a relationship between the positions of edges found by a typical image processing algorithm and actual dimensions is derived. The dimensional analysis is demonstrated on rat mesenteric resistance arteries (internal diameter less than 300 micrometer) mounted in a perfusion arteriograph. Segments of vessels are secured on two glass cannulae using single strands of a nylon braided suture. The artery is perfused with physiological salt solution and the perfusion pressure maintained at 60 mmHg before starting the experiment. Changes in vascular diameter to the vasoconstrictor noradrenaline and the endothelium-dependent vasodilator acetylcholine were then observed.

  6. Scatter Factor Induces Blood Vessel Formation in vivo

    NASA Astrophysics Data System (ADS)

    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

    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.

  7. Investigation on artificial blood vessels prepared from bacterial cellulose.

    PubMed

    Zang, Shanshan; Zhang, Ran; Chen, Hua; Lu, Yudong; Zhou, Jianhai; Chang, Xiao; Qiu, Guixing; Wu, Zhihong; Yang, Guang

    2015-01-01

    BC (bacterial cellulose) exhibits quite distinctive properties than plant cellulose. The outstanding properties make BC a promising material for preparation of artificial blood vessel. By taking advantage of the high oxygen permeability of PDMS (polydimethylsiloxane) as a tubular template material, a series of BC tubes with a length of 100 mm, a thickness of 1mm and an outer diameter of 4 or 6mm were biosynthesized with the help of Gluconacetobacter xylinum. Through characterization by SEM (scanning electron microscope), tensile testing and thermal analysis, it is demonstrated that BC tubes are good enough for artificial blood vessel with elaborated nano-fiber architecture, qualified mechanical properties and high thermal stability. In addition, measurement of biocompatibility also shows that BC tubes are greatly adaptable to the in vivo environment. The results indicate that BC tubes have great potential for being utilized as tubular scaffold materials in the field of tissue engineering. PMID:25491966

  8. Scatter factor induces blood vessel formation in vivo.

    PubMed Central

    Grant, D S; Kleinman, H K; Goldberg, I D; Bhargava, M M; Nickoloff, B J; Kinsella, J L; Polverini, P; Rosen, E M

    1993-01-01

    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. Images Fig. 1 Fig. 2 Fig. 3 Fig. 5 PMID:7680481

  9. Isolating and defining cells to engineer human blood vessels

    PubMed Central

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

    2012-01-01

    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

  10. Isolating and defining cells to engineer human blood vessels.

    PubMed

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

    2011-04-01

    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

  11. Modeling Of Blood Vessel Constriction In 2-D Case Using Molecular Dynamics Method

    E-print Network

    Mohamad Rendi; Suprijadi; Sparisoma Viridi

    2013-06-25

    Blood vessel constriction is simulated with particle-based method using a molecular dynamics authoring software known as Molecular Workbench (WM). Blood flow and vessel wall, the only components considered in constructing a blood vessel, are all represented in particle form with interaction potentials: Lennard-Jones potential, push-pull spring potential, and bending spring potential. Influence of medium or blood plasma is accommodated in plasma viscosity through Stokes drag force. It has been observed that pressure p is increased as constriction c is increased. Leakage of blood vessel starts at 80 % constriction, which shows existence of maximum pressure that can be overcome by vessel wall.

  12. Modeling Of Blood Vessel Constriction In 2-D Case Using Molecular Dynamics Method

    E-print Network

    Rendi, Mohamad; Viridi, Sparisoma

    2013-01-01

    Blood vessel constriction is simulated with particle-based method using a molecular dynamics authoring software known as Molecular Workbench (WM). Blood flow and vessel wall, the only components considered in constructing a blood vessel, are all represented in particle form with interaction potentials: Lennard-Jones potential, push-pull spring potential, and bending spring potential. Influence of medium or blood plasma is accommodated in plasma viscosity through Stokes drag force. It has been observed that pressure p is increased as constriction c is increased. Leakage of blood vessel starts at 80 % constriction, which shows existence of maximum pressure that can be overcome by vessel wall.

  13. Automatic retinal blood vessel parameter calculation in spectral domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wehbe, Hassan; Ruggeri, Marco; Jiao, Shuliang; Gregori, Giovanni; Puliafito, Carmen A.

    2007-02-01

    Measurement of retinal blood vessel parameters like the blood blow in the vessels may have significant impact on the study and diagnosis of glaucoma, a leading blinding disease worldwide. Optical coherence tomography (OCT) is a noninvasive imaging technique that can provide not only microscopic structural imaging of the retina but also functional information like the blood flow velocity in the retina. The aim of this study is to automatically extract the parameters of retinal blood vessels like the 3D orientation, the vessel diameters, as well as the corresponding absolute blood flow velocity in the vessel. The parameters were extracted from circular OCT scans around the optic disc. By removing the surface reflection through simple segmentation of the circular OCT scans a blood vessel shadowgram can be generated. The lateral coordinates and the diameter of each blood vessel are extracted from the shadowgram through a series of signal processing. Upon determination of the lateral position and the vessel diameter, the coordinate in the depth direction of each blood vessel is calculated in combination with the Doppler information for the vessel. The extraction of the vessel coordinates and diameter makes it possible to calculate the orientation of the vessel in reference to the direction of the incident sample light, which in turn can be used to calculate the absolute blood flow velocity and the flow rate.

  14. Blood vessel classification into arteries and veins in retinal images

    NASA Astrophysics Data System (ADS)

    Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

    2007-03-01

    The prevalence of diabetes is expected to increase dramatically in coming years; already today it accounts for a major proportion of the health care budget in many countries. Diabetic Retinopathy (DR), a micro vascular complication very often seen in diabetes patients, is the most common cause of visual loss in working age population of developed countries today. Since the possibility of slowing or even stopping the progress of this disease depends on the early detection of DR, an automatic analysis of fundus images would be of great help to the ophthalmologist due to the small size of the symptoms and the large number of patients. An important symptom for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins is indispensable. As to our knowledge despite the importance there have only been two approaches to vessel classification yet. Therefore we propose an improved method. We compare two feature extraction methods and two classification methods based on support vector machines and neural networks. Given a hand-segmentation of vessels our approach achieves 95.32% correctly classified vessel pixels. This value decreases by 10% on average, if the result of a segmentation algorithm is used as basis for the classification.

  15. Effect of non-Newtonian characteristics of blood on magnetic particle capture in occluded blood vessel

    NASA Astrophysics Data System (ADS)

    Bose, Sayan; Banerjee, Moloy

    2015-01-01

    Magnetic nanoparticles drug carriers continue to attract considerable interest for drug targeting in the treatment of cancer and other pathological conditions. Magnetic carrier particles with surface-bound drug molecules are injected into the vascular system upstream from the desired target site, and are captured at the target site via a local applied magnetic field. Herein, a numerical investigation of steady magnetic drug targeting (MDT) using functionalized magnetic micro-spheres in partly occluded blood vessel having a 90° bent is presented considering the effects of non-Newtonian characteristics of blood. An Eulerian-Lagrangian technique is adopted to resolve the hemodynamic flow and the motion of the magnetic particles in the flow using ANSYS FLUENT. An implantable infinitely long cylindrical current carrying conductor is used to create the requisite magnetic field. Targeted transport of the magnetic particles in a partly occluded vessel differs distinctly from the same in a regular unblocked vessel. Parametric investigation is conducted and the influence of the insert configuration and its position from the central plane of the artery (zoffset), particle size (dp) and its magnetic property (?) and the magnitude of current (I) on the "capture efficiency" (CE) is reported. Analysis shows that there exists an optimum regime of operating parameters for which deposition of the drug carrying magnetic particles in a target zone on the partly occluded vessel wall can be maximized. The results provide useful design bases for in vitro set up for the investigation of MDT in stenosed blood vessels.

  16. Annexin A3 Regulates Early Blood Vessel Formation

    PubMed Central

    Meadows, Stryder M.; Cleaver, Ondine

    2015-01-01

    Annexins are a large family of calcium binding proteins that associate with cell membrane phospholipids and are involved in various cellular processes including endocytosis, exocytosis and membrane-cytoskeletal organization. Despite studies on numerous Annexin proteins, the function of Annexin A3 (Anxa3) is largely unknown. Our studies identify Anxa3 as a unique marker of the endothelial and myeloid cell lineages of Xenopus laevis during development. Anxa3 transcripts are also detected in endothelial cells (ECs) of zebrafish and mouse embryos, suggesting an important evolutionary function during formation of blood vessels. Indeed, Anxa3 loss-of-function experiments in frog embryos reveal its critical role during the morphogenesis of early blood vessels, as angioblasts in MO injected embryos fail to form vascular cords. Furthermore, in vitro experiments in mammalian cells identify a role for Anxa3 in EC migration. Our results are the first to reveal an in vivo function for Anxa3 during vascular development and represent a previously unexplored aspect of annexin biology. PMID:26182056

  17. Automatic retinal blood vessel parameter calculation in spectral domain optical coherence tomography

    Microsoft Academic Search

    Hassan Wehbe; Marco Ruggeri; Shuliang Jiao; Giovanni Gregori; Carmen A. Puliafito

    2007-01-01

    Measurement of retinal blood vessel parameters like the blood blow in the vessels may have significant impact on the study and diagnosis of glaucoma, a leading blinding disease worldwide. Optical coherence tomography (OCT) is a noninvasive imaging technique that can provide not only microscopic structural imaging of the retina but also functional information like the blood flow velocity in the

  18. Blood Pressure, Vessel Caliber, and Retinal Thickness in Diabetes

    PubMed Central

    Harrison, Wendy W.; Chang, Ann; Cardenas, Maria; Bearse, Marcus A.; Schneck, Marilyn E.; Barez, Shirin; Adams, Anthony J.

    2012-01-01

    Purpose In this study we examine the association of blood pressure (BP), retinal thickness (RT), and vessel caliber in patients with type 2 diabetes and high HbA1c (elevated long-term blood glucose), either with or without mild or moderate non-proliferative diabetic retinopathy (NPDR). Methods Forty-three type 2 diabetes patients with high HbA1c measures (23 without NPDR and 20 with mild to moderate NPDR) and 22 age-matched, non-diabetic controls participated. BP, RT (Stratus OCT3), fundus photography, and HbA1c were measured. Correlations between BP, HbA1c, vessel caliber, and RT were evaluated. Results 1) Diastolic BP is positively and significantly associated with RT in patients with NPDR (p <0.02). BP was not associated with retinal thickness in patients without NPDR (p = 0.83). 2) There is an association between higher HbA1c and higher diastolic BP within the NPDR group (p<0.02). Furthermore, HbA1c modifies the slope of the relationship between diastolic BP and RT in NPDR patients. 3) Greater venule diameters and a loss of the correlation between decreased arteriole size and increased systolic blood pressure, seen in controls, were observed in patients with and without NPDR. Conclusions The results of this study show that HbA1c and BP together have an impact on the retinal thickness measures of patients with diabetic retinopathy. These measures should be considered when evaluating retinal thickness in patients with diabetic retinopathy, both clinically and in future OCT studies on this population. PMID:23160442

  19. Translating the Conversation Between the Brain and Blood Vessels

    NSDL National Science Digital Library

    APS Communications Office (American Physiological Society Communications Office)

    2006-04-21

    Â?WeÂ?re studying why people who are obese become hypertensive,Â? Dr. Schreihofer said of one aspect of her work. Â?We believe this is due to something about the obese state: We donÂ?t know what that is, but weÂ?re starting to rule things out.Â? Indeed, the Schreihofer laboratory has already answered one question: Does hypertension occur because the brain loses its ability to sense that the blood vessels are stretching under high pressure? In a study with obese rats, they found the ratsÂ? brains could sense the stretch but still became hypertensive, eliminating that mechanism as a possibility.

  20. Normalization of tumour blood vessels improves the delivery of nanomedicines in a size-dependent manner

    E-print Network

    Chauhan, Vikash P.

    The blood vessels of cancerous tumours are leaky and poorly organized. This can increase the interstitial fluid pressure inside tumours and reduce blood supply to them, which impairs drug delivery. Anti-angiogenic ...

  1. Changing topographic Hox expression in blood vessels results in regionally distinct vessel wall remodeling

    PubMed Central

    Pruett, Nathanael D.; Hajdu, Zoltan; Zhang, Jing; Visconti, Richard P.; Kern, Michael J.; Wellik, Deneen M.; Majesky, Mark W.; Awgulewitsch, Alexander

    2012-01-01

    Summary The distinct topographic Hox expression patterns observed in vascular smooth muscle cells (VSMCs) of the adult cardiovascular system suggest that these transcriptional regulators are critical for maintaining region-specific physiological properties of blood vessels. To test this proposition, we expanded the vascular Hoxc11 expression domain normally restricted to the lower limbs by utilizing an innovative integrated tetracycline regulatory system and Transgelin promoter elements to induce Hoxc11 expression universally in VSMCs of transgenic mice. Ectopic Hoxc11 expression in carotid arteries, aortic arch and descending aorta resulted in drastic vessel wall remodeling involving elastic laminae fragmentation, medial smooth muscle cell loss, and intimal lesion formation. None of these alterations were observed upon induction of Hoxc11 transgene expression in the femoral artery, i.e. the natural Hoxc11 activity domain, although this vessel was greatly enlarged, comparable to the topographically restricted vascular changes seen in Hoxc11?/? mice. To begin defining Hoxc11-controlled pathways of vascular remodeling, we performed immunolabeling studies in conjunction with co-transfection and chromatin immunoprecipitation (ChIP) assays using mouse vascular smooth muscle (MOVAS) cells. The results suggest direct transcriptional control of two members of the matrix metalloproteinase (Mmp) family, including Mmp2 and Mmp9 that are known as key players in the inception and progression of vascular remodeling events. In summary, the severe vascular abnormalities resulting from the induced dysregulated expression of a Hox gene with regional vascular patterning functions suggest that proper Hox function and regulation is critical for maintaining vascular functional integrity. PMID:23213434

  2. Targeted insult to subsurface cortical blood vessels using ultrashort laser pulses: three models of stroke

    E-print Network

    Cai, Long

    a vessel for injury and to measure blood-flow dynamics. We irradiated the vessel with high) An intravascular clot evolved when an extravasated vessel was further irradiated. Such clots dramatically impaired the removal of metabolites and heat. In the cerebral cortex, the vasculature forms networks of subsurface

  3. Aquaporin-1 in blood vessels of rat circumventricular organs.

    PubMed

    Wilson, Alan J; Carati, Colin J; Gannon, Bren J; Haberberger, Rainer; Chataway, Tim K

    2010-04-01

    Although the water channel protein aquaporin-1 (AQP1) is widely observed outside the rat brain in continuous, but not fenestrated, vascular endothelia, it has not previously been observed in any endothelia within the normal rat brain and only to a limited extent in the human brain. In this immunohistochemical study of rat brain, AQP1 has also been found in microvessel endothelia, probably of the fenestrated type, in all circumventricular organs (except the subcommissural organ and the vascular organ of the lamina terminalis): in the median eminence, pineal, subfornical organ, area postrema and choroid plexus. The majority of microvessels in the median eminence, pineal and choroid plexus, known to be exclusively fenestrated, are shown to be AQP1-immunoreactive. In the subfornical organ and area postrema in which many, but not all, microvessels are fenestrated, not all microvessels are AQP1-immunoreactive. In the AQP1-immunoreactive microvessels, the AQP1 probably facilitates water movement between blood and interstitium as one component of the normal fluxes that occur in these specialised sensory and secretory areas. AQP1-immunoreactive endothelia have also been seen in a small population of blood vessels in the cerebral parenchyma outside the circumventricular organs, similar to other observations in human brain. The proposed development of AQP1 modulators to treat various brain pathologies in which AQP1 plays a deleterious role will necessitate further work to determine the effect of such modulators on the normal function of the circumventricular organs. PMID:20177708

  4. Viscoelastic testing methodologies for tissue engineered blood vessels.

    PubMed

    Berglund, Joseph D; Nerem, Robert M; Sambanis, Athanassios

    2005-12-01

    In order to function in vivo, tissue engineered blood vessels (TEBVs) must encumber pulsatile blood flow and withstand hemodynamic pressures for long periods of time. To date TEBV mechanical assessment has typically relied on single time point burst and/or uniaxial tensile testing to gauge the strengths of the constructs. This study extends this analysis to include creep and stepwise stress relaxation viscoelastic testing methodologies. TEBV models exhibiting diverse mechanical behaviors as a result of different architectures ranging from reconstituted collagen gels to hybrid constructs reinforced with either untreated or glutaraldhyde-crosslinked collagen supports were evaluated after 8 and 23 days of in vitro culturing. Data were modeled using three and four-parameter linear viscoelastic mathematical representations and compared to porcine carotid arteries. While glutaraldhyde-treated hybrid TEBVs exhibited the largest overall strengths and toughness, uncrosslinked hybrid samples exhibited time-dependent behaviors most similar to native arteries. These findings emphasize the importance of viscoelastic characterization when evaluating the mechanical performance of TEBVs. Limits of testing methods and modeling systems are presented and discussed. PMID:16502660

  5. A New Device for Mechanical Testing of Blood Vessels at Cryogenic Temperatures

    E-print Network

    Rabin, Yoed

    modulus of a specimen with no cryoprotectant, at about -140°C (8.6 and 15.5°C below the glass transitionA New Device for Mechanical Testing of Blood Vessels at Cryogenic Temperatures J.L. Jimenez Rios study focuses on the development of a new device for mechanical testing of blood vessels at cryogenic

  6. Automated localization of macula-fovea area on retina images using blood vessel network topology

    Microsoft Academic Search

    Huajun Ying; Jyh-Charn Liu

    2010-01-01

    In this paper, we propose a simple yet robust unsupervised algorithm for automated localization of macula-fovea area on retina images. The small sizes and weak contrast of the macula-fovea area on retina images make it unreliable to detect it directly. As such, we extract the retina blood vessel network topology based on local energy function of blood vessel widths and

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

    Microsoft Academic Search

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

    1989-01-01

    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

  8. Tissue engineering of blood vessels with endothelial cells differentiated from mouse embryonic stem cells

    Microsoft Academic Search

    Gan SHEN; Hsiao Chien TSUNG; Chun Fang WU; Xiao Yin LIU; Xiaoyun WANG; Wei LIU; Lei CUI; Yi Lin CAO

    2003-01-01

    Endothelial cells (TEC3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8×106 smooth muscle cells (SMCs) obtained from rabbit arteries onto a sheet of nonwoven polyglycolic acid (PGA) fibers, which was used as a biodegradable polymer scaffold. After being cultured in DMEM medium

  9. Energy Analysis of Flow Induced Harmonic Motion in Blood Vessel Walls

    Microsoft Academic Search

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

    2005-01-01

    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

  10. Three-dimensional analysis of complex branching vessels in confocal microscopy images.

    PubMed

    Maddah, Mahnaz; Soltanian-Zadeh, Hamid; Afzali-Kusha, Ali; Shahrokni, Ali; Zhang, Zheng G

    2005-09-01

    The characteristic of confocal microscopy (CM) vascular data is that it contains many tiny vessels with branching and complex structure. In this work, an automated method for quantitative analysis and reconstruction of cerebral vessels from CM images is presented in which the extracted centerline of the vessels plays the key role. To assess the efficiency and accuracy of different centerline extraction methods, a comparison among three fully automated approaches is given. The centerline extraction methods studied in this work are a snake model, a path planning approach, and a distance transform-based method. To evaluate the accuracy of the quantitative parameters of vessels such as length and diameter, we apply the method to synthetic data. These results indicate that the snake model and the path planning method are more accurate in extracting the quantitative parameters. The efficiency of the approach in clinical applications is then confirmed by applying the method to real CM images. All three methods investigated in this work are accurate enough to correctly distinguish between normal and stroke brain data, while the snake model is the fastest for clinical applications. In addition, three-dimensional visualization, reconstruction, and characterization of CM vascular images of rat brains are presented. PMID:15996853

  11. Numerical investigation of blood flow in a deformable coronary bifurcation and non-planar branch

    PubMed Central

    Razavi, Seyed Esmail; Omidi, Amir Ali; Saghafi Zanjani, Massoud

    2014-01-01

    Introduction: Among cardiovascular diseases, arterials stenosis is recognized more commonly than the others. Hemodynamic characteristics of blood play a key role in the incidence of stenosis. This paper numerically investigates the pulsatile blood flow in a coronary bifurcation with a non-planar branch. To create a more realistic analysis, the wall is assumed to be compliant. Furthermore, the flow is considered to be three-dimensional, incompressible, and laminar. Methods: The effects of non-Newtonian blood, compliant walls and different angles of bifurcation on hemodynamic characteristics of flow were evaluated. Shear thinning of blood was simulated with the Carreau-Yasuda model. The current research was mainly focused on the flow characteristics in bifurcations since atherosclerosis occurs mostly in bifurcations. Moreover, as the areas with low shear stresses are prone to stenosis, these areas were identified. Results: Our findings indicated that the compliant model of the wall, bifurcation’s angle, and other physical properties of flow have an impact on hemodynamics of blood flow. Lower wall shear stress was observed in the compliant wall than that in the rigid wall. The outer wall of bifurcation in all models had lower wall shear stress. In bifurcations with larger angles, wall shear stress was higher in outer walls, and lower in inner walls. Conclusion: The non-Newtonian blood vessels and different angles of bifurcation on hemodynamic characteristics of flow evaluation confirmed a lower wall shear stress in the compliant wall than that in the rigid wall, while the wall shear stress was higher in outer walls but lower in inner walls in the bifurcation regions with larger angles. PMID:25671176

  12. Blood Vessel Deformations on Microsecond Time Scales by Ultrasonic Cavitation

    PubMed Central

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

    2011-01-01

    Transient interactions among ultrasound, microbubbles, and microvessels were studied using high-speed photomicrography. We observed liquid jets, vessel distention (motion outward against the surrounding tissue), and vessel invagination (motion inward toward the lumen). Contrary to current paradigms, liquid jets were directed away from the nearest vessel wall and invagination exceeded distention. These observations provide insight into the mechanics of bubble-vessel interactions, which appear to depend qualitatively upon the mechanical properties of biological tissues. PMID:21405276

  13. Fluid Forces Combine with Molecular Signal to Trigger New Blood Vessel Growth | Physical Sciences in Oncology

    Cancer.gov

    Angiogenesis, the growth of new blood vessels, is required for the development and spread of cancer, but the physical and biochemical factors that trigger this complex process are poorly understood. Using a microfluidic model of angiogenic sprouting, the initial visible step in new blood vessel formation, a pair of investigators from Harvard Medical School has shown that the sheer stress produced by flowing blood plays a critical role in early angiogenesis.

  14. Computer Simulations of Pulsatile Human Blood Flow Through 3D-Models of the Human Aortic Arch, Vessels of Simple Geometry and a Bifurcated Artery: Investigation of Blood Viscosity and Turbulent Effects

    E-print Network

    Sultanov, Renat A

    2008-01-01

    We report computational results of blood flow through a model of the human aortic arch and a vessel of actual diameter and length. On the top of the aortic arch the branching of the %%three arteries are included: the subclavian and jugular. A realistic pulsatile flow is used in all simulations. Calculations for bifurcation type vessels are also carried out and presented. Different mathematical methods for numerical solution of the fluid dynamics equations have been considered. The non-Newtonian behaviour of the human blood is investigated together with turbulence effects. A detailed time-dependent mathematical convergence test has been carried out. The results of computer simulations of the blood flow in vessels of three different geometries are presented: for pressure, strain rate and velocity component distributions we found significant disagreements between our results obtained with realistic non-Newtonian treatment of human blood and the widely used method in the literature: a simple Newtonian approximati...

  15. Effect of configuration between cryoprobe and large blood vessels on the tissue freezing during cryosurgery.

    PubMed

    Deng, Zhong-Shan; Liu, Jing

    2005-01-01

    For accurate predictions of the tissue temperature distribution during cryosurgery a thermal model should incorporate the individual impact of large blood vessels. In presence of large vessel, configuring cryoprobe becomes very important because misplacement of cryoprobes may result in either inadequate cooling temperatures in the target tissue due to the heating nature of large vessels or undesired damage to the downstream healthy tissues and organs as a result of arresting of key vessels. In this article, typical vascular models are applied to investigate the effects of large blood vessels and cryoprobe configurations on the transient temperature profiles of cooled tissues during cryosurgery. The thermal model describing heat transfer to or from large vessels is based on heat transfer coefficient derived from analytical solutions of forced convection in cylindrical ducts. A finite difference algorithm developed in our previous study is used to solve this complex problem with phase change heat transfer in biological tissues embedded with large blood vessels. Numerical computations are then performed to predict the transient temperature distributions of tissues under three different configurations of cryoprobe. The results indicate that different configurations of cryoprobe can produce significantly different temperature profiles and blood vessel heating in cooled tissues. Results of this study should be considered in the strategy for an optimal placement of cryoprobes when performing cryosurgical treatments in the vicinity of large blood vessels. PMID:17282223

  16. Transmitted ultrasound pressure variation in micro blood vessel phantoms.

    PubMed

    Qin, Shengping; Kruse, Dustin E; Ferrara, Katherine W

    2008-06-01

    Silica, cellulose and polymethylmethacrylate tubes with inner diameters of ten to a few hundred microns are commonly used as blood vessel phantoms in in vitro studies of microbubble or nanodroplet behavior during insonation. However, a detailed investigation of the ultrasonic fields within these micro-tubes has not yet been performed. This work provides a theoretical analysis of the ultrasonic fields within micro-tubes. Numerical results show that for the same tube material, the interaction between the micro-tube and megaHertz-frequency ultrasound may vary drastically with incident frequency, tube diameter and wall thickness. For 10 MHz ultrasonic insonation of a polymethylmethacrylate (PMMA) tube with an inner diameter of 195 microm and an outer diameter of 260 microm, the peak pressure within the tube can be up to 300% of incident pressure amplitude. However, using 1 MHz ultrasound and a silica tube with an inner diameter of 12 microm and an outer diameter of 50 microm, the peak pressure within the tube is only 12% of the incident pressure amplitude and correspondingly, the spatial-average-time-average intensity within the tube is only 1% of the incident intensity. PMID:18395962

  17. Connective tissue growth factor (CCN2) in blood vessels.

    PubMed

    Ponticos, Markella

    2013-03-01

    The CCN family comprise the products of six immediate-early response genes (Cyr61, Ctgf, Nov and Wisp1-3) and are multi-functional proteins, characterised by four discrete protein modules in which reside functional domains: an insulin-like growth factor binding protein-like module (IGFBP) but has low affinity for IGFBPs, a von Willebrand factor type C repeat module (VWC) which mediates integrin and growth factor binding, a thrombospondin type-1 repeat module (TSP-1), and a cysteine-knot-containing module (CT). These modules mediate a host of interactions such as growth factor binding, integrin recognition, and interaction(s) with heparin and proteoglycans (reviewed in Holbourn et al., 2008; Chen and Lau, 2009). The CCN family are involved in many normal and pathological cellular processes and have a plethora of functions including cell proliferation, angiogenesis, wound healing, and fibrogenesis, tumourigenesis. In addition, many roles have been described for CCN family members in the cardiovascular system (Table 1). The focus of this review is the role of connective tissue growth factor (CCN2, CTGF) in blood vessels and in vascular pathology. PMID:23380714

  18. Modeling CD40-based molecular communications in blood vessels.

    PubMed

    Felicetti, Luca; Femminella, Mauro; Reali, Gianluca; Gresele, Paolo; Malvestiti, Marco; Daigle, John N

    2014-09-01

    This paper presents a mathematical characterization of the main features of the molecular communication between platelets and endothelial cells via CD40 signaling during the initial phases of atherosclerosis, known also as atherogenesis. We demonstrate through laboratory experimentation that the release of soluble CD40L molecules from platelets in a fluid medium is enough to trigger expression of adhesion molecules on endothelial cell's surface; that is, physical contact between the platelets and the endothelial cells is not necessary. We also propose the mathematical model of this communication, and we quantify the model parameters by matching the experiment results to the model. In addition, this mathematical model of platelet-endothelium interaction, along with propagation models typical of blood vessels, is incorporated into a simulation platform. Analysis of the simulation results indicates that these enhancements render the simulator a useful tool upon which to base discussion for planning research, and has the potential to be an important step in the understanding, diagnosis, and treatment of cardiovascular diseases. PMID:25095259

  19. Fpga based hardware synthesis for automatic segmentation of retinal blood vessels in diabetic retinopathy images.

    PubMed

    Sivakamasundari, J; Kavitha, G; Sujatha, C M; Ramakrishnan, S

    2014-01-01

    Diabetic Retinopathy (DR) is a disorder that affects the structure of retinal blood vessels due to long-standing diabetes mellitus. Real-Time mass screening system for DR is vital for timely diagnosis and periodic screening to prevent the patient from severe visual loss. Human retinal fundus images are widely used for an automated segmentation of blood vessel and diagnosis of various blood vessel disorders. In this work, an attempt has been made to perform hardware synthesis of Kirsch template based edge detection for segmentation of blood vessels. This method is implemented using LabVIEW software and is synthesized in field programmable gate array board to yield results in real-time application. The segmentation of blood vessels using Kirsch based edge detection is compared with other edge detection methods such as Sobel, Prewitt and Canny. The texture features such as energy, entropy, contrast, mean, homogeneity and structural feature namely ratio of vessel to vessel free area are obtained from the segmented images. The performance of segmentation is analysed in terms of sensitivity, specificity and accuracy. It is observed from the results that the Kirsch based edge detection technique segmented the edges of blood vessels better than other edge detection techniques. The ratio of vessel to vessel free area classified the normal and DR affected retinal images more significantly than other texture based features. FPGA based hardware synthesis of Kirsch edge detection method is able to differentiate normal and diseased images with high specificity (93%). This automated segmentation of retinal blood vessels system could be used in computer-assisted diagnosis for diabetic retinopathy screening in real-time application. PMID:25405418

  20. Grading system for blood vessel tumor emboli of invasive ductal carcinoma of the breast.

    PubMed

    Sugiyama, Michiko; Hasebe, Takahiro; Shimada, Hiroko; Takeuchi, Hideki; Shimizu, Kyoko; Shimizu, Michio; Yasuda, Masanori; Ueda, Shigeto; Shigekawa, Takashi; Osaki, Akihiko; Saeki, Toshiaki

    2015-06-01

    We previously reported that the number of mitotic and apoptotic figures in tumor cells in blood vessel tumor emboli had the greatest significant power for the accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. The purpose of the present study was to devise a grading system for blood vessel tumor emboli based on the mitotic and apoptotic figures of tumor cells in blood vessel tumor emboli, enabling accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. We classified 263 invasive ductal carcinomas into the following 3 grades according to the numbers of mitotic and apoptotic figures in tumor cells located in blood vessels within 1 high-power field: grade 0, no blood vessel invasion; grade 1, absence of mitotic figures and presence of any number of apoptotic figures, or 1 mitotic figure and 0 to 2 apoptotic figures; and grade 2, 1 mitotic figure and 3 or more apoptotic figures, or 2 or more mitotic figures and 1 or more apoptotic figures. Multivariate analyses with well-known prognostic factors demonstrated that grade 2 blood vessel tumor emboli significantly increased the hazard ratios for tumor recurrence independent of the nodal status, pathological TNM stage, hormone receptor status, or HER2 status. The presently reported grading system for blood vessel tumor emboli is the strongest histologic factor for accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. PMID:25890786

  1. Biological and engineering design considerations for vascular tissue engineered blood vessels (TEBVs)

    PubMed Central

    Fernandez, Cristina E.; Achneck, Hardean E.; Reichert, William M.; Truskey, George A.

    2014-01-01

    Considerable advances have occurred in the development of tissue-engineered blood vessels (TEBVs) to repair or replace injured blood vessels, or as in vitro systems for drug toxicity testing. Here we summarize approaches to produce TEBVs and review current efforts to (1) identify suitable cell sources for the endothelium and vascular smooth muscle cells, (2) design the scaffold to mimic the arterial mechanical properties and (3) regulate the functional state of the cells of the vessel wall. Initial clinical studies have established the feasibility of this approach and challenges that make TEBVs a viable alternative for vessel replacement are identified. PMID:24511460

  2. Immersive Volume Rendering of Blood Vessels Gregory Long, Han Suk Kim, Alison Marsden, Yuri Bazilevs, Jurgen P. Schulze

    E-print Network

    Schulze, Jürgen P.

    Immersive Volume Rendering of Blood Vessels Gregory Long, Han Suk Kim, Alison Marsden, Yuri ABSTRACT In this paper, we present a novel method of visualizing flow in blood vessels. Our approach reads to the sparse structure of blood vessels, we utilize an octree to efficiently store the resampled data

  3. Retinal vessel width measurement at branching points using an improved electric field theory-based graph approach

    NASA Astrophysics Data System (ADS)

    Xu, Xiayu; Abràmoff, Michael D.; Bertelsen, Geir; Reinhardt, Joseph M.

    2012-02-01

    An accurate and fully automatic method to measure the vessel width at branching points in fundus images is presented. This method is a graph-based method, in which an electric field theory based graph construction method is applied to specifically deal with the complicated branching patterns. The vessel centerline image is used as the initial segmentation. The branching points are detected on the vessel centerline image using a series of detection kernels. Crossing points are distinguished from branching points and excluded in this study. Electric field theory motivated graph construction method is applied to construct the graph, inspired by the non-intersecting property of the electric line of force. Of the three branches in a branching unit, the one closest to the optic disc is automatically detected as the parent branch and the other two are regarded as the daughter branches. The location of the optic disc is automatically detected based on a machine learning technique. The method was validated on a set of 50 fundus images.

  4. Segmentation and length measurement of the abdominal blood vessels in 3-D MRI images.

    PubMed

    Babin, Danilo; Vansteenkiste, Ewout; Pizurica, Aleksandra; Philips, Wilfried

    2009-01-01

    In diagnosing diseases and planning surgeries the structure and length of blood vessels is of great importance. In this research we develop a novel method for the segmentation of 2-D and 3-D images with an application to blood vessel length measurements in 3-D abdominal MRI images. Our approach is robust to noise and does not require contrast-enhanced images for segmentation. We use an effective algorithm for skeletonization, graph construction and shortest path estimation to measure the length of blood vessels of interest. PMID:19964361

  5. Selective Stimulation of Penumbral Cones Reveals Perception in the Shadow of Retinal Blood Vessels

    PubMed Central

    Spitschan, Manuel; Aguirre, Geoffrey K.; Brainard, David H.

    2015-01-01

    In 1819, Johann Purkinje described how a moving light source that displaces the shadow of the retinal blood vessels to adjacent cones can produce the entopic percept of a branching tree. Here, we describe a novel method for producing a similar percept. We used a device that mixes 56 narrowband primaries under computer control, in conjunction with the method of silent substitution, to present observers with a spectral modulation that selectively targeted penumbral cones in the shadow of the retinal blood vessels. Such a modulation elicits a clear Purkinje-tree percept. We show that the percept is specific to penumbral L and M cone stimulation and is not produced by selective penumbral S cone stimulation. The Purkinje-tree percept was strongest at 16 Hz and fell off at lower (8 Hz) and higher (32 Hz) temporal frequencies. Selective stimulation of open-field cones that are not in shadow, with penumbral cones silenced, also produced the percept, but it was not seen when penumbral and open-field cones were modulated together. This indicates the need for spatial contrast between penumbral and open-field cones to create the Purkinje-tree percept. Our observation provides a new means for studying the response of retinally stabilized images and demonstrates that penumbral cones can support spatial vision. Further, the result illustrates a way in which silent substitution techniques can fail to be silent. We show that inadvertent penumbral cone stimulation can accompany melanopsin-directed modulations that are designed only to silence open-field cones. This in turn can result in visual responses that might be mistaken as melanopsin-driven. PMID:25897842

  6. SIMULATION OF DISCRETE BLOOD VESSEL EFFECTS ON THE THERMAL SIGNATURE OF A MELANOMA LESION.

    PubMed

    Kandala, Sri Kamal; Deng, Daxiang; Herman, Cila

    2013-01-01

    The effect of the underlying blood vessel on the transient thermal response of the skin surface with and without a melanoma lesion is studied. A 3D computational model of the layers of the skin tissue with cancerous lesion was developed in COMSOL software package. Heat transfer in the skin layers and the lesion is governed by the Pennes bio-heat equation, while the blood vessel is modeled as fully developed pipe flow with constant heat transfer coefficient. The effect of various pertinent parameters, such as diameter of the blood vessel, lateral location of the blood vessel relative to the lesion, flow velocity of the blood, on the skin surface temperature distribution, have been studied in the paper. The results show significant influence of the underlying blood vessel on the temperature of the skin surface and lesion as well as on the surrounding healthy tissue. Thus, a need for development of evaluation criteria for detection of malignant lesions in the presence of blood vessels is is discussed. PMID:25328916

  7. A simplified model for red cell dynamics in small blood vessels

    E-print Network

    Piero Olla

    1998-11-20

    A simple mechanism for the confinement of red cells in the middle of narrow blood vessels is proposed. In the presence of a quadratic shear, red cells deform in such a way to loose fore-aft symmetry and to achieve a fixed orientation with respect to the flow. This leads to a drift away from the vessel walls, when the vessel diameter goes below a critical value depending on the viscoelastic properties and the dimensions of the cell.

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

    E-print Network

    Chauhan, Vikash P.

    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 ...

  9. In vivo experiments and numerical investigations on nanocryosurgical freezing of target tissues with large blood vessels.

    PubMed

    Sun, Zi-Qiao; Yang, Yang; Liu, Jing

    2012-02-01

    This study presented the first in vivo animal experiments of using nano-cryosurgical modality to completely freezing tumor tissues embedded with large blood vessels, which is a tough issue to tackle otherwise. Three-dimensional theoretical simulations were also performed on the complex freezing problems by considering flow and heat transfer of blood flow in large vessels. According to the experimental measurements and numerical predictions, injecting the nanoparticles with high thermal conductivity into the freezing target can significantly reduce the heating effect of blood vessel, shorten the freezing time, and enlarge the freezing range. Most importantly, the introduction of nanoparticles successfully overcomes the classical challenges in completely ablating the tumor region with large blood vessel and enhancing the freezing efficacy of cryosurgery. This investigation consolidates the practical and theoretical foundation for nano-cryosurgery which suggests a highly efficient freezing strategy for treating late stage tumor. PMID:22515090

  10. Automatic detection of blood vessels in retinal images for diabetic retinopathy diagnosis.

    PubMed

    Raja, D Siva Sundhara; Vasuki, S

    2015-01-01

    Diabetic retinopathy (DR) is a leading cause of vision loss in diabetic patients. DR is mainly caused due to the damage of retinal blood vessels in the diabetic patients. It is essential to detect and segment the retinal blood vessels for DR detection and diagnosis, which prevents earlier vision loss in diabetic patients. The computer aided automatic detection and segmentation of blood vessels through the elimination of optic disc (OD) region in retina are proposed in this paper. The OD region is segmented using anisotropic diffusion filter and subsequentially the retinal blood vessels are detected using mathematical binary morphological operations. The proposed methodology is tested on two different publicly available datasets and achieved 93.99% sensitivity, 98.37% specificity, 98.08% accuracy in DRIVE dataset and 93.6% sensitivity, 98.96% specificity, and 95.94% accuracy in STARE dataset, respectively. PMID:25810749

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

    PubMed Central

    Nie, Kai; Molnár, Zoltán; Szele, Francis G.

    2010-01-01

    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. PMID:20616553

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

    PubMed Central

    Reif, Roberto

    2012-01-01

    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

  13. Estimation of Blood Flow Speed and Vessel Location from Thermal Video M. Garbey A. Merla

    E-print Network

    Estimation of Blood Flow Speed and Vessel Location from Thermal Video M. Garbey A. Merla I and vessel location from thermal video. The method is based on a bioheat transfer model that re- flects and dynamic states on data provided by a thermal imaging system. Our method opens exciting possibilities

  14. Remodeling of Blood Vessels Responses of Diameter and Wall Thickness to Hemodynamic and Metabolic Stimuli

    Microsoft Academic Search

    Axel R. Pries; Bettina Reglin; Timothy W. Secomb

    Vascular functions, including tissue perfusion and peripheral resistance, reflect continuous structural adaptation (remodeling) of blood vessels in response to several stimuli. Here, a theoretical model is presented that relates the structural and functional properties of microvascular networks to the adaptive responses of individual segments to hemodynamic and metabolic stimuli. All vessels are assumed to respond, according to a common set

  15. Optical monitoring of ultrasound interaction with blood vessels in transparent fish after injection with contrast agents

    Microsoft Academic Search

    S. Maruvada; K. Hynynen

    2002-01-01

    The goal of this research is to study the ultrasonic therapeutic effects on the blood vessels of animals whose vessels are optically transparent. Glass catfish were used in these experiments Anaesthetized fish were injected with Optison using microinjection techniques. Two focused transducers were used to cover a frequency range of 0.7-3.3 MHz. An inverted microscope combined with a digital camera

  16. THE EFFECT OF MAGNESIUM SULPHATE ON THE BLOOD VESSELS OF THE UPPER LIMB IN MAN

    Microsoft Academic Search

    DB Frewin; YF Teh; RF Whelan

    1971-01-01

    Magnesium sulphate, given into the brachial artery, has been shown to have a dilator action on the blood vessels of the human forearm.The dilatation affects the vessels of both skin and muscle and is not due to stimulation of the ?-receptors to a cholinergic mechanism or to the release of histamine.The vasodilator action of magnesium sulphate on the forearm does

  17. [Architecture and fine structure of the terminal blood vessels in the marginal papillae of the tongue in newborn piglets].

    PubMed

    Schlechta, C; Kressin, M; Schnorr, B; Krebs, C

    1996-04-01

    The vascular architecture of the marginal papillae of the tongue was examined in one to five day old piglets by means of light and transmission electron microscopy and scanning microscopy of vascular corrosion casts. The marginal papillae of the tongue exhibit a "rope ladder-like" principle of blood supply. Every papilla contains one ascending arteriole, which branches into single capillary loops each supplying a protrusion of the multiply branched base of the capillary body. The transition of the arteriole takes place on the tip of the papilla. Subsequently the capillary loops converge onto this venule. Precapillary sphincters are observed at the origin of the capillary loops. This type of vessel arrangement offers the opportunity to use the capillary system at maximum efficiency, thus allowing an erection of the papillae marginales during the process of suckling. PMID:8638767

  18. Engineering a Blood Vessel Network Module for Body-on-a-Chip Applications.

    PubMed

    Ryu, Hyunryul; Oh, Soojung; Lee, Hyun Jae; Lee, Jin Young; Lee, Hae Kwang; Jeon, Noo Li

    2015-06-01

    The blood circulatory system links all organs from one to another to support and maintain each organ's functions consistently. Therefore, blood vessels have been considered as a vital unit. Engineering perfusable functional blood vessels in vitro has been challenging due to difficulties in designing the connection between rigid macroscale tubes and fragile microscale ones. Here, we propose a generalizable method to engineer a "long" perfusable blood vessel network. To form millimeter-scale vessels, fibroblasts were co-cultured with human umbilical vein endothelial cells (HUVECs) in close proximity. In contrast to previous works, in which all cells were permanently placed within the device, we developed a novel method to culture paracrine factor secreting fibroblasts on an O-ring-shaped guide that can be transferred in and out. This approach affords flexibility in co-culture, where the effects of secreted factors can be decoupled. Using this, blood vessels with length up to 2 mm were successfully produced in a reproducible manner (>90%). Because the vessels form a perfusable network within the channel, simple links to inlets and outlets of the device allowed connections to the outside world. The robust and reproducible formation of in vitro engineered vessels can be used as a module to link various organ components as parts of future body-on-a-chip applications. PMID:25532526

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

    SciTech Connect

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

    2013-07-31

    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. (laser applications in biology and medicine)

  20. Growth and Remodeling in Blood Vessels Studied In Vivo With Fractal Analysis

    NASA Technical Reports Server (NTRS)

    Parsons-Wingerter, Patricia A.

    2003-01-01

    Every cell in the human body must reside in close proximity to a blood vessel (within approximately 200 mm) because blood vessels provide the oxygen, metabolite, and fluid exchanges required for cellular existence. The growth and remodeling of blood vessels are required to support the normal physiology of embryonic development, reproductive biology, wound healing and adaptive remodeling to exercise, as well as abnormal tissue change in diseases such as cancer, diabetes, and coronary heart disease. Cardiovascular and hemodynamic (blood flow dynamics) alterations experienced by astronauts during long-term spaceflight, including orthostatic intolerance, fluid shifts in the body, and reduced numbers of red (erythrocyte) and white (immune) blood cells, are identified as risk factors of very high priority in the NASA task force report on risk reduction for human spaceflight, the "Critical Path Roadmap."

  1. Simultaneous Irradiation and Imaging of Blood Vessels During Pulsed

    E-print Network

    Barton, Jennifer K.

    Design/Materials and Methods: A modified scanning laser confocal microscope recorded vessel response biopsies. Surface information provided real-time but only indirect evidence of events that occurred

  2. Development of three dimensional blood vessel search system by using on stereo and autofocus hybrid method.

    PubMed

    Nakamachi, E

    2011-01-01

    In this study, we developed an accurate three dimensional blood vessel search (3D BVS) system and an automatic operated blood sampling system. These systems were implemented into the point-of-care system for the ubiquitous medical care, which was featured as the portable type self-monitoring blood glucose (SMBG) devise. It resolved the human error problem, which causes by the complicated manual operation of blood sampling and blood glucose measurement in conventional SMBG devices. In this study, we mainly discuss the performance examination of accurate position detection of blood vessel. Our 3D BVS system employed the near-infrared (NIR) light imaging process and the stereo and autofocus hybrid method to determine the 3D blood vessel location accurately. We evaluated the accuracy of our 3D BVS system by using the phantom of human skin, blood vessel and blood. As a result, we validated a very good performance ability of our 3D BVS system for a portable type SMBG device. PMID:22255741

  3. Computational study of thermal effects of large blood vessels in human knee joint.

    PubMed

    Xue, Xu; He, Zhi Zhu; Liu, Jing

    2013-01-01

    This paper is dedicated to present a comprehensive investigation on the thermal effects of large blood vessels of human knee joint during topical cooling and fomentation treatment. A three-dimensional (3D) finite element analysis by taking full use of the anatomical CAD model of human knee joint was developed to accurately simulate the treatment process. Based on the classical Pennes bio-heat transfer equation, the time evolution of knee joint's temperature distribution and heat flux from large blood vessels was obtained. In addition, we compared several influencing factors and obtained some key conclusions which cannot be easily acquired through clinical experiments. The results indicated that the thermal effects of large blood vessels could remarkably affect the temperature distribution of knee joint during treatment process. Fluctuations of blood flow velocity and metabolic heat production rate affect little on the thermal effects of large blood vessels. Changing the temperature of blood and regimes of treatment could effectively regulate this phenomenon, which is important for many physiological activities. These results provide a guideline to the basic and applied research for the thermally significant large blood vessels in the knee organism. PMID:23196147

  4. Determination of the mechanical properties of the different layers of blood vessels in vivo.

    PubMed Central

    Fung, Y C; Liu, S Q

    1995-01-01

    The structure and materials of the blood vessel wall are layered. This article presents the principle of a method to determine the mechanical properties of the different layers in vivo. In vivo measurement begets in vivo data and avoids pitfalls of in vitro tests of dissected specimens. With the proposed method, we can measure vessels of diameters 100 microns and up and obtain data on vascular smooth muscles and adventitia. To derive the full constitutive equations, one must first determine the zero-stress state, obtain the morphometric data on the thicknesses of the layers, and make mechanical measurements in the neighborhood of the zero-stress state. Then eight small perturbation experiments are done on earth blood vessel in vivo to determine eight incremental elastic moduli of the two layers of the blood vessel wall. The calculation requires the morphometric data and the location of the neutral axis. The experiments are simple, the interpretation is definitive, but the analysis is somewhat sophisticated. The method will yield results that are needed to assess the stress and strain in the tissues of the blood vessel. The subject is important because blood vessels remodel themselves significantly and rapidly when their stress and strain deviate from their homeostatic values, and because cell proliferation, differentiation, adhesion, contraction, and locomotion depend on stress and strain in the tissue. Images Fig. 1 PMID:7892241

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

    PubMed Central

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

    2011-01-01

    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. PMID:21467177

  6. Blood Vessel Contributions to Retinal Nerve Fiber Layer Thickness Profiles Measured With Optical Coherence Tomography

    PubMed Central

    Hood, Donald C.; Fortune, Brad; Arthur, Stella N.; Xing, Danli; Salant, Jennifer A.; Ritch, Robert; Liebmann, Jeffrey M.

    2010-01-01

    Purpose To understand better the influence of retinal blood vessels (BVs) on the interindividual variation in the retinal nerve fiber layer (RNFL) thickness measured with optical coherence tomography (OCT). Subjects and Methods RNFL thickness profiles were measured by OCT in 16 control individuals and 16 patients. The patients had advanced glaucoma defined by abnormal disc appearance, abnormal visual fields, and a mean visual field deviation worse than ? 10 dB. Results In general, the OCT RNFL thickness profiles showed 4 local maxima, with the peak amplitudes in the superior and inferior regions occurring in the temporal (peripapillary) disc region. There was considerable variability among individuals in the location of these maxima. However, the 4 maxima typically fell on, or near, a major BV with the temporal and inferior peaks nearly always associated with the main temporal branches of the superior and inferior veins and arteries. In the patients’ hemifields with severe loss (mean visual field deviation worse than ? 20 dB), the signals associated with the major BVs were in the order of 100 to 150 µm. Conclusions The variation in the local peaks of the RNFL profiles of controls correlates well with the location of the main temporal branches of the superior and inferior veins and arteries. This correspondence is, in part, due to a direct BV contribution to the shape of the OCT RNFL and, in part, due to the fact that BVs develop along the densest regions of axons. Although the overall BV contribution was estimated to be relatively modest, roughly 13% of the total peripapillary RNFL thickness in controls, their contribution represents a substantial portion locally and increases in importance with disease progression. PMID:18854727

  7. Gene targeting of VEGF-A in thymus epithelium disrupts thymus blood vessel architecture

    PubMed Central

    Müller, Susanna M.; Terszowski, Grzegorz; Blum, Carmen; Haller, Corinne; Anquez, Viviane; Kuschert, Stephen; Carmeliet, Peter; Augustin, Hellmut G.; Rodewald, Hans-Reimer

    2005-01-01

    The thymus harbors an organ-typical dense network of branching and anastomosing blood vessels. To address the molecular basis for morphogenesis of this thymus-specific vascular pattern, we have inactivated a key vascular growth factor, VEGF-A, in thymus epithelial cells (TECs). Both Vegf-A alleles were deleted in TECs by a complementation strategy termed nude mouse [mutated in the transcription factor Foxn1 (forkhead box N1)] blastocyst complementation. Injection of Foxn1+/+ ES cells into Foxn1nu/nu blastocysts reconstituted a functional thymus. By dissecting thymus stromal cell subsets, we have defined, in addition to medullary TECs (mTECs) and cortical TECs (cTECs), another prominent stromal cell subset designated cortical mesenchymal cells (cMes). In chimeric thymi, mTECs and cTECs but not cMes were exclusively ES cell-derived. According to this distinct origin, the Vegf-A gene was deleted in mTECs and cTECs, whereas cMes still expressed Vegf-A. This genetic mosaic was associated with hypovascularization and disruption of the organ-typical network of vascular arcades. Thus, vascular growth factor production by TECs is required for normal thymus vascular architecture. These experiments provide insights into Foxn1-dependent and Foxn1-independent stromal cell development and demonstrate the value of this chimeric approach to analyzing gene function in thymus epithelium. PMID:16027358

  8. Blood Flow At Arterial Branches: Complexities To Resolve For The Angioplasty Suite

    E-print Network

    Laidlaw, David

    Blood Flow At Arterial Branches: Complexities To Resolve For The Angioplasty Suite P.D. Richardson1 the flows in a branched artery, to compare them with prior physical flow visualization, and to interpret them with further users in mind. The geometry was taken for a typical epicardial coronary artery

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

  10. Segmentation of the blood vessels and optic disk in retinal images.

    PubMed

    Salazar-Gonzalez, Ana; Kaba, Djibril; Li, Yongmin; Liu, Xiaohui

    2014-11-01

    Retinal image analysis is increasingly prominent as a nonintrusive diagnosis method in modern ophthalmology. In this paper, we present a novel method to segment blood vessels and optic disk in the fundus retinal images. The method could be used to support nonintrusive diagnosis in modern ophthalmology since the morphology of the blood vessel and the optic disk is an important indicator for diseases like diabetic retinopathy, glaucoma, and hypertension. Our method takes as first step the extraction of the retina vascular tree using the graph cut technique. The blood vessel information is then used to estimate the location of the optic disk. The optic disk segmentation is performed using two alternative methods. The Markov random field (MRF) image reconstruction method segments the optic disk by removing vessels from the optic disk region, and the compensation factor method segments the optic disk using the prior local intensity knowledge of the vessels. The proposed method is tested on three public datasets, DIARETDB1, DRIVE, and STARE. The results and comparison with alternative methods show that our method achieved exceptional performance in segmenting the blood vessel and optic disk. PMID:25265617

  11. Aging changes in the heart and blood vessels

    MedlinePLUS

    ... although certain white blood cells important to immunity (neutrophils) decrease in their number and ability to fight ... aging. In Goldman L, Schafer AI, eds. Cecil Medicine . 24th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap ...

  12. The promotion of endothelial progenitor cells recruitment by nerve growth factors in tissue-engineered blood vessels

    Microsoft Academic Search

    Wen Zeng; Wei Yuan; Li Li; Jianhong Mi; Shangcheng Xu; Can Wen; Zhenhua Zhou; Jiaqiang xiong; Jiansen Sun; Dajun Ying; Mingcan Yang; Xiaosong Li; Chuhong Zhu

    2010-01-01

    Endothelial progenitor cells (EPCs) mobilization and homing are critical to the development of an anti-thrombosis and anti-stenosis tissue-engineered blood vessel. The growth and activation of blood vessels are supported by nerves. We investigated whether nerve growth factors (NGF) can promote EPCs mobilization and endothelialization of tissue-engineered blood vessels. In vitro, NGF promoted EPCs to form more colonies, stimulated human EPCs

  13. Vessel Labeling in Combined Confocal Scanning Laser Ophthalmoscopy and Optical Coherence Tomography Images: Criteria for Blood Vessel Discrimination

    PubMed Central

    Motte, Jeremias; Alten, Florian; Ewering, Carina; Osada, Nani; Kadas, Ella M.; Brandt, Alexander U.; Oberwahrenbrock, Timm; Clemens, Christoph R.; Eter, Nicole; Paul, Friedemann; Marziniak, Martin

    2014-01-01

    Introduction The diagnostic potential of optical coherence tomography (OCT) in neurological diseases is intensively discussed. Besides the sectional view of the retina, modern OCT scanners produce a simultaneous top-view confocal scanning laser ophthalmoscopy (cSLO) image including the option to evaluate retinal vessels. A correct discrimination between arteries and veins (labeling) is vital for detecting vascular differences between healthy subjects and patients. Up to now, criteria for labeling (cSLO) images generated by OCT scanners do not exist. Objective This study reviewed labeling criteria originally developed for color fundus photography (CFP) images. Methods The criteria were modified to reflect the cSLO technique, followed by development of a protocol for labeling blood vessels. These criteria were based on main aspects such as central light reflex, brightness, and vessel thickness, as well as on some additional criteria such as vascular crossing patterns and the context of the vessel tree. Results and Conclusion They demonstrated excellent inter-rater agreement and validity, which seems to indicate that labeling of images might no longer require more than one rater. This algorithm extends the diagnostic possibilities offered by OCT investigations. PMID:25203135

  14. [Core structure of acupoint: interactive network of immune, blood vessel and nerve].

    PubMed

    Luo, Mingfu

    2015-02-01

    The studying on interrelation and interaction among blood-vessel network, nerve network and immune network is considered to be the key to reveal the mechanism of acupuncture treatment and the essence of meridians. A strip-like compound structure of mast cells, blood vessel and nerve network is observed in acupoint area. From its systematics nature and correlation with acupuncture effect and meridian phenomena, it is believed that the structure of mast cells, blood vessel and nerve network is an interactive system with interrelation and interaction among each other, and is an essential site and pivot to produce and transport matter, energy and information, and is the core structure of acupoint. PMID:25854024

  15. Fluorescence microscopic morphometry of functioning blood vessels and adrenergic nerves in myocardium.

    PubMed

    Muntz, K H; Hagler, H K; Boulas, H J; Buja, L M

    1984-01-01

    The purpose of this study was to quantify the percent volume of actively functioning blood vessels in five dogs subjected to ligation of the left anterior descending artery and to localize catecholamine-containing nerve terminals in the same tissue blocks. Radioactive microspheres were injected to determine the extent of flow reduction in the ischemic zone. After 1 or 3 hr of occlusion, thioflavin-S (0.125 ml/Kg of a 4% solution) was injected intravenously 15 sec prior to removal of the heart. Tissue samples were reacted with paraformaldehyde to visualize catecholamine-containing nerve terminals prior to embedding in paraffin. The percent volume of blood vessels labeled with thioflavin-S was quantitated in tissue sections using a point-counting technique in which a small dot from a video screen was projected through an image-projecting tube and moved by computer control over the image of the fluorescent tissue. In the nonischemic zone, the mean blood flow determined by the microsphere technique was 1.29 ml/min/g +/- 0.48 (SD), and the mean volume percent of thioflavin-labeled vessels was 12.67 +/- 3.30. In the ischemic and border zone areas, there was wide range of flow reduction, and there was a significant correlation between the blood flow measured with microspheres and the percent volume of thioflavin-labeled blood vessels (R = 0.80, P less than 0.001). In the nonischemic zone, both blood vessels and catecholamine-containing nerve terminals were visible; however, in the ischemic zone, few labeled vessels were seen, although nerve terminals were often present.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6711839

  16. Evaluation of side effects of radiofrequency capacitive hyperthermia with magnetite on the blood vessel walls of tumor metastatic lesion surrounding the abdominal large vessels: an agar phantom study

    PubMed Central

    2014-01-01

    Background Magnetite used in an 8-MHz radiofrequency (RF) capacitive heating device can increase the temperature of a specific site up to 45°C. When treating a metastatic lesion around large abdominal vessels via hyperthermia with magnetite, heating-induced adverse effects on these vessels need to be considered. Therefore, this study examined hyperthermia-induced damage to blood vessel walls in vitro. Methods A large agar phantom with a circulatory system consisting of a swine artery and vein connected to a peristaltic pump was prepared. The blood vessels were placed on the magnetite-containing agar piece. Heating was continued for 30 min at 45°C. After heating, a histological study for injury to the blood vessels was performed. Results The inner membrane temperature did not reach 45°C due to the cooling effect of the blood flow. In the heated vessels, vascular wall collagen degenerated and smooth muscle cells were narrowed; however, no serious changes were noted in the vascular endothelial cells or vascular wall elastic fibers. The heated vessel wall was not severely damaged; this was attributed to cooling by the blood flow. Conclusions Our findings indicate that RF capacitive heating therapy with magnetite may be used for metastatic lesions without injuring the surrounding large abdominal vessels. PMID:25114787

  17. Direct mecA Detection from Blood Culture Bottles by Branched-DNA Signal Amplification

    Microsoft Academic Search

    X. ZHENG; C. P. KOLBERT; P. VARGA-DELMORE; J. ARRUDA; M. LEWIS; J. KOLBERG; F. R. COCKERILL; D. H. PERSING; Bayer Diagnostics

    1999-01-01

    A branched-DNA (bDNA) signal amplification method was used to detect the mecA gene directly from blood culture broth growing staphylococci. BACTEC blood culture bottles with positive growth indices and contain- ing staphylococcus-like organisms as shown by Gram stain were tested for the presence of the mecA gene. Comparison of test results was done among 225 patients (one blood culture from

  18. Quantification of Blood Vessel Tortuosity and its Impact on Fenestrated Aortic Stent Grafts Research project will be undertaken at Toronto General Hospital under the supervision of Dr. Leonard

    E-print Network

    Quantification of Blood Vessel Tortuosity and its Impact on Fenestrated Aortic Stent Grafts of fenestrated aortic stent grafts. Tortuosity is a measure of the deviation of a blood vessel from a straight line path. With age and disease, blood vessels tend to become more tortuous due to vessel lengthening

  19. Role of Peptide YY in blood vessel function and atherosclerosis in a rabbit model.

    PubMed

    Smith, Renee M; Klein, Rudi; Kruzliak, Peter; Zulli, Anthony

    2015-06-01

    Cardiovascular disease remains a burden for Westernized countries. Peptide YY (PYY) raises blood pressure, yet its role has not yet been determined in diseased arteries. This study aimed at identifying PYY and eNOS in diseased blood vessels and to determine which blood vessels respond to PYY. New Zealand White rabbits were fed an atherogenic diet (n = 6, 0.5% cholesterol + 1% methionine + 5% peanut oil) and control animals fed a normal diet (n = 6) for 4 weeks. Immunohistochemistry was used to determine the localization of PYY and eNOS in the aorta. The aorta, carotid, renal, iliac, inferior mesenteric, and renal interlobular arteries were removed, mounted in organ baths, and subjected to doses of PYY (10(-9) -10(-7)  mol/L) and then acetylcholine (10(-6)  mol/L). Immunohistochemistry of the aorta shows PYY staining in plaque macrophages, smooth muscle cells and endothelium, and these cells co-expressed eNOS. PYY caused a minor vasoconstrictive response in all blood vessels studied but was blunted in arteries from control animals. Acetylcholine caused relaxation of PYY constricted blood vessels. This data clearly shows that PYY is present in atherosclerotic plaque and is a minor constrictor of the vasculature tree. Further studies aimed at understanding the role of PYY in cardiovascular disease are warranted. PMID:25854545

  20. Characterization of Pax3-expressing cells from adult blood vessels

    E-print Network

    .085373 Summary We report expression of Pax3, an important regulator of skeletal muscle stem cell cells by flow cytometry, established their vascular smooth muscle identity. These blood contribute to muscle fibre formation when co-cultured with skeletal muscle cells. This myogenic conversion

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

  2. Occlusion of Small Vessels by Malaria-Infected Red Blood Cells

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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.

  3. Polysaccharides from astragali radix restore chemical-induced blood vessel loss in zebrafish

    PubMed Central

    2012-01-01

    Background Astragali Radix has been used widely for the treatment of cardiovascular and cerebrovascular diseases, and to enhance endurance and stamina in traditional Chinese medicine (TCM) for over 2000 years. The polysaccharide constituents of Astragali Radix (ARP) are considered as one of the major constituents contributing to the multiple pharmacological effects of this medicinal plant. The purpose of the study is to evaluate the vascular regenerative activities of ARPs in a chemically-induced blood vessel loss model in zebrafish. Methods Blood vessel loss was induced in both Tg(fli-1a:EGFP)y1 and Tg(fli-1a:nEGFP)y7 embryos by administration of 300 nM VEGFR tyrosine kinase inhibitor II (VRI) for 3 h at 24 hpf (hour post-fertilization). Then, the blood vessel damaged zebrafish were treated with ARPs for 21 h and 45 h after VRI withdrawal. Morphological changes in intersegmental vessels (ISVs) of zebrafish larvae were observed under the fluorescence microscope and measured quantitatively. The rescue effect of ARPs in the zebrafish models was validated by measuring the relative mRNA expressions of Kdrl, Kdr and Flt-1 using real-time PCR. Results Two polysaccharide fractions, P4 (50000 D < molecular weight & diameter < 0.1 ?m) and P5 (molecular diameter > 0.1 ?m), isolated from Astragali Radix by ultrafiltration, produced a significant and dose-dependent recovery in VRI-induced blood vessel loss in zebrafish. Furthermore, the down-regulation of Flk-1 and Flt-1 mRNA expression induced by VRI was reversed by treatment with P4. Conclusion The present study demonstrates that P4 isolated from Astragali Radix reduces VRI-induced blood vessel loss in zebrafish. These findings support the hypothesis that polysaccharides are one of the active constituents in Astragali Radix, contributing to its beneficial effect on treatment of diseases associated with a deficiency in angiogenesis. PMID:22357377

  4. Intravenously administered phosphodiesterase 4 inhibitors dilate retinal blood vessels in rats

    Microsoft Academic Search

    Tomoyo Miwa; Asami Mori; Tsutomu Nakahara; Kunio Ishii

    2009-01-01

    In the present study, we examined effects of intravenously administered inhibitors of phosphodiesterase 4 (rolipram and 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro-20-1724)) and non-selective inhibitor of phosphodiesterases (theophylline) on diameter of retinal blood vessel and fundus (retinal\\/choroidal) blood flow in rats. Male Wistar rats (8- to 10-week-old) were treated with tetrodotoxin (50 ?g\\/kg, i.v.) to eliminate any nerve activity and prevent the eye movement under

  5. Vessel Wall and Blood Flow Dynamics in Arterial Disease

    Microsoft Academic Search

    R. J. Lusby; H. I. Machleder; W. Jeans; R. Skidmore; J. P. Woodcock; P. C. Clifford; R. N. Baird

    1981-01-01

    Recent developments in ultrasound techniques have made it possible to investigate patients with arterial disease non-invasively by using Doppler blood velocity signal analysis. Since January 1979, 189 patients with pre-stroke syndromes have been investigated by using pulsed Doppler and real-time B-mode ultrasound imaging and waveform analysis. The results were that both imaging systems were highly (more than 92%) sensitive and

  6. A new seeded region growing technique for retinal blood vessels extraction.

    PubMed

    Sajadi, Atefeh Sadat; Sabzpoushan, Seyed Hojat

    2014-07-01

    Distribution of retinal blood vessels (RBVs) in retinal images has an important role in the prevention, diagnosis, monitoring and treatment of diseases, such as diabetes, high blood pressure, or heart disease. Therefore, detection of the exact location of RBVs is very important for Ophthalmologists. One of the frequently used techniques for extraction of these vessels is region growing-based Segmentation. In this paper, we propose a new region growing (RG) technique for RBVs extraction, called cellular automata-based segmentation. RG techniques often require manually seed point selection, that is, human intervention. However, due to the complex structure of vessels in retinal images, manual tracking of them is very difficult. Therefore, to make our proposed technique full automatic, we use an automatic seed point selection method. The proposed RG technique was tested on Digital Retinal Images for Vessel Extraction database for three different initial seed sets and evaluated against the manual segmentation of retinal images available at this database. Three quantitative criteria including accuracy, true positive rate and false positive rate, were considered to evaluate this method. The visual scrutiny of the segmentation results and the quantitative criteria show that, using cellular automata for extracting the blood vessels is promising. However, the important point at here is that the correct initial seeds have an effective role on the final results of segmentation. PMID:25298931

  7. Normalization of tumour blood vessels improves the delivery of nanomedicines in a size-dependent manner

    NASA Astrophysics Data System (ADS)

    Chauhan, Vikash P.; Stylianopoulos, Triantafyllos; Martin, John D.; Popovi?, Zoran; Chen, Ou; Kamoun, Walid S.; Bawendi, Moungi G.; Fukumura, Dai; Jain, Rakesh K.

    2012-06-01

    The blood vessels of cancerous tumours are leaky and poorly organized. This can increase the interstitial fluid pressure inside tumours and reduce blood supply to them, which impairs drug delivery. Anti-angiogenic therapies--which `normalize' the abnormal blood vessels in tumours by making them less leaky--have been shown to improve the delivery and effectiveness of chemotherapeutics with low molecular weights, but it remains unclear whether normalizing tumour vessels can improve the delivery of nanomedicines. Here, we show that repairing the abnormal vessels in mammary tumours, by blocking vascular endothelial growth factor receptor-2, improves the delivery of smaller nanoparticles (diameter, 12 nm) while hindering the delivery of larger nanoparticles (diameter, 125 nm). Using a mathematical model, we show that reducing the sizes of pores in the walls of vessels through normalization decreases the interstitial fluid pressure in tumours, thus allowing small nanoparticles to enter them more rapidly. However, increased steric and hydrodynamic hindrances, also associated with smaller pores, make it more difficult for large nanoparticles to enter tumours. Our results further suggest that smaller (~12 nm) nanomedicines are ideal for cancer therapy due to their superior tumour penetration.

  8. Quantification of mast cells and blood vessels in the skin of patients with cutaneous mucinosis.

    PubMed

    Martins, Clarice; Nascimento, Adriana Paulino; Monte-Alto-Costa, Andréa; Alves, Maria de Fátima Scotelaro; Carneiro, Sueli Coelho; Porto, Luís Cristóvão de Moraes Sobrino

    2010-07-01

    Recent studies have suggested that mast cell numbers are increased in the skin of patients with cutaneous mucinosis and that these cells may have an important role in angiogenesis and production of mucin. Then, skin biopsies from 30 patients with cutaneous mucinosis (papular mucinosis, focal mucinosis, and mucinosis associated with lupus erythematosus) and from 10 healthy subjects were analyzed. Mast cells and blood vessels were immunolabeled with anti-tryptase and anti-CD34 antibodies, respectively, and then quantified stereologically. Counting was performed in papillary and reticular dermis. An increase in the number of mast cells was observed in the skin of patients with cutaneous mucinosis compared with the control group. Only minimal differences were observed in vessel stereology. There was no correlation between the increase in the number of mast cells and the number of blood vessels in the patients studied. There was no significant difference in the numbers of mast cells or blood vessels between the 3 subgroups of cutaneous mucinosis. Although many clinical forms of mucinosis have been described, neither mast cell number nor vessel distribution seems to distinguish the 3 different forms studied here. PMID:20442641

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

    PubMed Central

    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

    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. PMID:18720007

  10. Vessel segmentation and blood flow simulation using Level-Sets and Embedded Boundary methods

    E-print Network

    . Introduction Computational Fluid Dynamics (CFD) simulations of complex flows in vascular passagesVessel segmentation and blood flow simulation using Level-Sets and Embedded Boundary methods T flow simulation in realistic vascular objects. The anatomical surfaces are extracted by means of Level

  11. Mouse lung contains endothelial progenitors with high capacity to form blood and lymphatic vessels

    Microsoft Academic Search

    Judith Schniedermann; Moritz Rennecke; Kerstin Buttler; Georg Richter; Anna-Maria Städtler; Susanne Norgall; Muhammad Badar; Bernhard Barleon; Tobias May; Jörg Wilting; Herbert A Weich

    2010-01-01

    BACKGROUND: Postnatal endothelial progenitor cells (EPCs) have been successfully isolated from whole bone marrow, blood and the walls of conduit vessels. They can, therefore, be classified into circulating and resident progenitor cells. The differentiation capacity of resident lung endothelial progenitor cells from mouse has not been evaluated. RESULTS: In an attempt to isolate differentiated mature endothelial cells from mouse lung

  12. The Finite Element Method Applied to a Problem of Blood Flow in Vessels

    PubMed Central

    Nu?, Gabriela; Chiorean, Ioana; Cri?an, Maria

    2012-01-01

    We use the finite element method to solve a convection-diffusion equation when convection is dominating, a problem which describes the behavior of the concentration of a solute in a blood vessel. A new technique for computing the discrete problem is used. PMID:22319548

  13. Tissue-Engineered Vascular Grafts as In Vitro Blood Vessel Mimics for the Evaluation of Endothelialization

    E-print Network

    Barton, Jennifer K.

    Tissue-Engineered Vascular Grafts as In Vitro Blood Vessel Mimics for the Evaluation-diameter vascular bypass conduits, many research groups have developed tissue-engineered vascular grafts (TEVGs).5 studies. This is possible based on current capabilities for the creation of tissue-engineered vascular

  14. VEGF121 and VEGF165 Regulate Blood Vessel Diameter Through Vascular Endothelial Growth Factor Receptor

    E-print Network

    Hughes, Christopher C. W.

    VEGF121 and VEGF165 Regulate Blood Vessel Diameter Through Vascular Endothelial Growth Factor, Orange, California SUMMARY: Vascular endothelial growth factor (VEGF) is essential for the induction of angiogenesis and drives both endothelial cell (EC) proliferation and migration. It has been suggested that VEGF

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

    Microsoft Academic Search

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

    2007-01-01

    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

  16. New feature-based detection of blood vessels and exudates in color fundus images

    Microsoft Academic Search

    Doaa Youssef; Nahed Solouma; Amr El-dib; Mai Mabrouk; Abo-Bakr Youssef

    2010-01-01

    Exudates are one of the earliest and most prevalent symptoms of diseases leading to blindness such as diabetic retinopathy and wet macular degeneration. Certain areas of the retina with such conditions are to be photocoagulated by laser to stop the disease progress and prevent blindness. Outlining these areas is dependent on outlining the exudates, the blood vessels, the optic disc

  17. Automatic optic disc detection using retinal background and retinal blood vessels

    Microsoft Academic Search

    Shijian Lu

    2010-01-01

    This paper presents an automatic optic disc detection technique that locates the optic disc through retinal background surface estimation and retinal blood vessel analysis. In the proposed technique, a retinal background surface is first estimated through an iterative Savitzky-Golay smoothing procedure. Multiple optic disc candidates are then detected from the difference between the retinal image under study and the estimated

  18. Accurate detection of blood vessels improves the detection of exudates in color fundus images.

    PubMed

    Youssef, Doaa; Solouma, Nahed H

    2012-12-01

    Exudates are one of the earliest and most prevalent symptoms of diseases leading to blindness such as diabetic retinopathy and macular degeneration. Certain areas of the retina with such conditions are to be photocoagulated by laser to stop the disease progress and prevent blindness. Outlining these areas is dependent on outlining the lesions and the anatomic structures of the retina. In this paper, we provide a new method for the detection of blood vessels that improves the detection of exudates in fundus photographs. The method starts with an edge detection algorithm which results in a over segmented image. Then the new feature-based algorithm can be used to accurately detect the blood vessels. This algorithm considers the characteristics of a retinal blood vessel such as its width range, intensities and orientations for the purpose of selective segmentation. Because of its bulb shape and its color similarity with exudates, the optic disc can be detected using the common Hough transform technique. The extracted blood vessel tree and optic disc could be subtracted from the over segmented image to get an initial estimate of exudates. The final estimation of exudates can then be obtained by morphological reconstruction based on the appearance of exudates. This method is shown to be promising since it increases the sensitivity and specificity of exudates detection to 80% and 100% respectively. PMID:22818584

  19. Dynamic Mechanical Conditioning of Collagen-Gel Blood Vessel Constructs Induces Remodeling In Vitro

    Microsoft Academic Search

    Dror Seliktar; Richard A. Black; Raymond P. Vito; Robert M. Nerem

    2000-01-01

    Dynamic mechanical conditioning is investigated as a means of improving the mechanical properties of tissue-engineered blood vessel constructs composed of living cells embedded in a collagen-gel scaffold. This approach attempts to elicit a unique response from the embedded cells so as to reorganize their surrounding matrix, thus improving the overall mechanical stability of the constructs. Mechanical conditioning, in the form

  20. A Blood Vessel Model Constructed from Collagen and Cultured Vascular Cells

    Microsoft Academic Search

    Crispin B. Weinberg; Eugene Bell

    1986-01-01

    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

  1. Enhanced Bonding Strength of Hydrophobically Modified Gelatin Films on Wet Blood Vessels

    PubMed Central

    Yoshizawa, Keiko; Taguchi, Tetsushi

    2014-01-01

    The bonding behavior between hydrophobically modified alkaline-treated gelatin (hm-AlGltn) films and porcine blood vessels was evaluated under wet conditions. Hexanoyl (Hx: C6), decanoyl (Dec: C10), and stearyl (Ste: C18) chlorides were introduced into the amino groups of AlGltn to obtain HxAlGltn, DecAlGltn, and SteAlGltn, respectively, with various modification percentages. The hm-AlGltn was fabricated into films and thermally crosslinked to obtain water-insoluble films (t-hm-AlGltn). The 42% modified t-HxAlGltn (t-42HxAlGltn) possessed higher wettability than the 38% modified t-DecAlGltn (t-38DecAlGltn) and the 44% modified t-SteAlGltn (t-44SteAlGltn) films, and the t-42HxAlGltn film showed a high bonding strength with the blood vessel compared with all the hm-AlGltn films. Histological observations indicated that t-42HxAlGltn and t-38DecAlGltn remained on the blood vessel even after the bonding strength measurements. From cell culture experiments, the t-42HxAlGltn films showed significant cell adhesion compared to other films. These findings indicate that the Hx group easily interpenetrated the surface of blood vessels and effectively enhanced the bonding strength between the films and the tissue. PMID:24481063

  2. Cellular/Molecular Glial Cells Dilate and Constrict Blood Vessels: A Mechanism

    E-print Network

    Newman, Eric A.

    Cellular/Molecular Glial Cells Dilate and Constrict Blood Vessels: A Mechanism of Neurovascular, termed neurovascular coupling, is widely used to monitor human brain function and diagnose pathology cells to neurovascular coupling in the acutely isolated mammalian retina. We found that light

  3. Blood Vessels Segmentation in Non-Mydriatic Images Using Wavelets and Statistical Classi.ers

    Microsoft Academic Search

    Jorge J. G. Leandro; João V. B. Soares; Roberto M. Cesar; Herbert F. Jelinek

    2003-01-01

    This work describes a new framework for automatic analysis of optic fundus nonmydriatic images, focusing on the segmentation of the blood vessels by using pixel classification based on pattern recognition techniques. Each pixel is represented by a feature vector composed of color information and measurements at different scales taken from the continuous wavelet (Morlet) transform as well as from mean

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

    Microsoft Academic Search

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

    2010-01-01

    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

  5. Circulating fibrocytes stabilize blood vessels during angiogenesis in a paracrine manner.

    PubMed

    Li, Jinqing; Tan, Hong; Wang, Xiaolin; Li, Yuejun; Samuelson, Lisa; Li, Xueyong; Cui, Caibin; Gerber, David A

    2014-02-01

    Accumulating evidence supports that circulating fibrocytes play important roles in angiogenesis. However, the specific role of fibrocytes in angiogenesis and the underlying mechanisms remain unclear. In this study, we found that fibrocytes stabilized newly formed blood vessels in a mouse wound-healing model by inhibiting angiogenesis during the proliferative phase and inhibiting blood vessel regression during the remodeling phase. Fibrocytes also inhibited angiogenesis in a Matrigel mouse model. In vitro study showed that fibrocytes inhibited both the apoptosis and proliferation of vascular endothelial cells (VECs) in a permeable support (Transwell) co-culture system. In a three-dimensional collagen gel, fibrocytes stabilized the VEC tubes by decreasing VEC tube density on stimulation with growth factors and preventing VEC tube regression on withdrawal of growth factors. Further mechanistic investigation revealed that fibrocytes expressed many prosurvival factors that are responsible for the prosurvival effect of fibrocytes on VECs and blood vessels. Fibrocytes also expressed angiogenesis inhibitors, including thrombospondin-1 (THBS1). THBS1 knockdown partially blocked the fibrocyte-induced inhibition of VEC proliferation in the Transwell co-culture system and recovered the fibrocyte-induced decrease of VEC tube density in collagen gel. Purified fibrocytes transfected with THBS1 siRNA partially recovered the fibrocyte-induced inhibition of angiogenesis in both the wound-healing and Matrigel models. In conclusion, our findings reveal that fibrocytes stabilize blood vessels via prosurvival factors and anti-angiogenic factors, including THBS1. PMID:24300950

  6. Designing A Pattern Stabilization Method Using Scleral Blood Vessels For Laser Eye Surgery

    E-print Network

    Erdem, Erkut

    Designing A Pattern Stabilization Method Using Scleral Blood Vessels For Laser Eye Surgery Aydin,abc}@cs.hacettepe.edu.tr, hbcakmak@gmail.com Abstract-- In laser eye surgery, the accuracy of operation depends on coherent eye tracking and registration techniques. Main approach used in image processing based eye trackers

  7. Bone, blood vessels, and muscle detection algorithm and creating database based on dynamic and non-dynamic multi-slice CT image of head and neck

    NASA Astrophysics Data System (ADS)

    Shabbir Ahamed, Mohammed; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Iwasaki, Hirokazu

    2007-03-01

    Nowadays, dental CT images play more and more important roles in oral clinical applications. Our research is important particularly in the field of dentistry. We are using non-dynamic and dynamic CT image for our research. We are creating our database of bone, blood vessels and muscles of head and neck. This database contains easy case and difficult case of head and neck's bone, blood vessels and muscle. There are lots of difficult cases in our database. Teeth separation and condylar process separation is difficult case. External carotid artery has many branches and they are attached with vain so it is difficult to separate. All muscle threshold value is same and they are attaching with each other so muscle separation is very difficult. These databases also contain different age's patients. For this reason our database becomes an important tool for dental students and also important assets for diagnosis. After completion our database we can link it with other dental application.

  8. All optical thrombotic stroke model for near-surface blood vessels in rat: Focal illumination of exogenous photosensitizers combined with

    E-print Network

    Kleinfeld, David

    of an intravenously injected photosensitizer, rose bengal. The dynamics of blood flow and clot formation to the study of blood flow and vessel dynamics soon after blood flow is reduced. Many models rely ischemia-induced lesions, offer limited insight into the blood flow dynamics that occur during a thrombotic

  9. Histomorphometry of umbilical cord blood vessels in preeclampsia.

    PubMed

    Blanco, Manuel V; Vega, Hilda R; Giuliano, Rodolfo; Grana, Daniel R; Azzato, Francisco; Lerman, Jorge; Milei, Jose

    2011-01-01

    The authors hypothesized that preeclampsia may change the phenotype of umbilical cord vessels. Segments of umbilical cords were obtained from 29 pregnant women (20 healthy and 9 with preeclampsia), which were histomorphometrically assessed. Birth weight was 2928 ± 613 g for the control group vs 1749 ± 656 g for the preeclampsia group (P<.0001). A significantly shorter gestational period was noted in the preeclampsia group: 35 weeks vs 39 weeks in the healthy group. Measurements of the outer layer area (116.4 ± 55 ?m(2) vs 56.5±25 ?m(2) ; P=.0038), the inner layer area (63.1 ± 16 ?m(2) vs 28.6±8 ?m(2) ; P<.0001), the lumen area (8.4 ± 1 ?m(2) vs 3.4±2 ?m(2) ; P=.0003), and the wall/lumen ratio (20.3 ± 9 vs 3.1 ± 0.6; P<.0001) of arteries were significantly larger in the preeclampsia umbilical cords. Concerning veins, the wall/lumen ratio was higher in the preeclampsia group. In this study, the umbilical cord in preeclampsia showed significant changes in the structure of umbilical arteries, with increases in wall areas and wall/lumen ratios. PMID:21214719

  10. Subgross and macroscopic investigation of blood vessels originating from aortic arch in the chinchilla (Chinchilla lanigera).

    PubMed

    Ozdemir, V; Cevik-Demirkan, A; Türkmeno?lu, I

    2008-04-01

    A total of 10 adult, healthy, male chinchilla (Chinchilla lanigera) were used to investigate the vessels originating from aortic arch. Coloured latex was injected into the carotid arteries following conventional anatomical applications in all the chinchillas examined. The brachiocephalic trunk and the left subclavian artery arose from the aortic arch at the level of the second intercostal region in the thoracic cavity. The right and left subclavian arteries detached branches at the level of first intercostal region and divided into the following vessels: internal thoracic artery, dorsal scapular artery, vertebral artery, superficial cervical artery and axillar artery. The vessels originating from the aortic arch displayed some significant differences in chinchillas compared to rats, guinea pigs, rabbits, porcupines and other laboratory rodents. PMID:18005370

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

    NASA Astrophysics Data System (ADS)

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

    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.

  12. Investigation of blood flow and the effect of vasoactive substances in cutaneous blood vessels of Xenopus laevis.

    PubMed

    Škorjanc, Aleš; Beluši?, Gregor

    2015-06-01

    In the present study, a preparation of frog skin was presented, which can be used to demonstrate the basic concepts of blood flow regulation in a very clear and attractive way to high school and university students. In a freshly euthanized Xenopus, a patch of abdominal skin was exposed from the internal side and viewed with a USB microscope while it remained connected to a functioning circulatory system. In this way, it was possible to obtain sharp images of arteries and veins and to visualize blood flow. This allows students to learn about the functional differences between arteries and veins and about the complexity of hemodynamics as well as the particularities of the amphibian pulmocutaneous circulation. Students can then quantitatively estimate the effect of norepinephrine and epinephrine on the diameter of blood vessels by simply superfusing the skin patch with a series of solutions of the two substances. They can also test the effect of ?-adrenergic receptor blockers, used to treat high blood pressure, on the norepinephrine-induced muscle tonus of blood vessels. PMID:26031724

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

    PubMed Central

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

    2009-01-01

    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. PMID:18851139

  14. Automated characterization of blood vessels as arteries and veins in retinal images.

    PubMed

    Mirsharif, Qazaleh; Tajeripour, Farshad; Pourreza, Hamidreza

    2013-01-01

    In recent years researchers have found that alternations in arterial or venular tree of the retinal vasculature are associated with several public health problems such as diabetic retinopathy which is also the leading cause of blindness in the world. A prerequisite for automated assessment of subtle changes in arteries and veins, is to accurately separate those vessels from each other. This is a difficult task due to high similarity between arteries and veins in addition to variation of color and non-uniform illumination inter and intra retinal images. In this paper a novel structural and automated method is presented for artery/vein classification of blood vessels in retinal images. The proposed method consists of three main steps. In the first step, several image enhancement techniques are employed to improve the images. Then a specific feature extraction process is applied to separate major arteries from veins. Indeed, vessels are divided to smaller segments and feature extraction and vessel classification are applied to each small vessel segment instead of each vessel point. Finally, a post processing step is added to improve the results obtained from the previous step using structural characteristics of the retinal vascular network. In the last stage, vessel features at intersection and bifurcation points are processed for detection of arterial and venular sub trees. Ultimately vessel labels are revised by publishing the dominant label through each identified connected tree of arteries or veins. Evaluation of the proposed approach against two different datasets of retinal images including DRIVE database demonstrates the good performance and robustness of the method. The proposed method may be used for determination of arteriolar to venular diameter ratio in retinal images. Also the proposed method potentially allows for further investigation of labels of thinner arteries and veins which might be found by tracing them back to the major vessels. PMID:23849699

  15. Divergent changes of flow through individual blood vessels upon localized heating.

    PubMed

    Rhee, J G; Eddy, H A; Hong, J J; Suntharalingam, M; Vaupel, P W

    1996-01-01

    The changes of microregional perfusion in a hamster cheek pouch membrane were investigated. The vessel network of the membrane was visualized by preparing a transparent chamber, which was heated with circulating water at 42 degree C. Blood perfusion was monitored by using a laser Doppler flowmeter (LDF), which was used either in a conventional way by positioning the probe stationary or in a novel way by constantly moving the probe over the surface of the chamber (scanning). When a segment of tissue was subjected to the LDF scanning, the profile of scanned LDF values was well correlated with the distribution of vessels. Therefore, this scanning technique was useful in localizing the probe in tissues with respect to vessels. Since the scanning can be repeated every other minute, this technique also offered continuous monitoring of tissue blood flow at multiple sites. Upon heating, different vessels individually responded to the first and second heatings followed by coolings, suggesting a heterogeneous heat response in the connective tissue of the hamster cheek pouch membrane. This scanning technique proved very useful in collecting information for the study of the heterogeneous nature of blood flow in normal and tumour tissues. PMID:8950156

  16. Material-mediated proangiogenic factor release pattern modulates quality of regenerated blood vessels.

    PubMed

    Rich, Max H; Lee, Min Kyung; Baek, Kwanghyun; Jeong, Jae Hyun; Kim, Dong Hyun; Millet, Larry J; Bashir, Rashid; Kong, Hyunjoon

    2014-12-28

    Hydrogels designed to sustainably release bioactive molecules are extensively used to enhance tissue repair and regenerative therapies. Along this line, numerous efforts are made to control the molecular release rate and amount. In contrast, few efforts are made to control the molecular release pattern, and, subsequently, modulate the spatial organization of newly forming tissues, including blood vessels. Therefore, using a hydrogel printed to release vascular endothelial growth factor (VEGF) into a pre-defined pattern, this study demonstrates that spatial distribution of VEGF is important in guiding growth direction of new blood vessels, and also in retaining the structural integrity of pre-existing vasculature. Guided by a computational model, we fabricated a patch composed of micro-sized VEGF-releasing poly(ethylene glycol) diacrylate (PEGDA) hydrogel cylinders using an ink-jet printer. Interestingly, hydrogel printed with computationally optimized spacing created anisotropically aligned vasculature exclusively when the printed gel pattern was placed parallel to pre-existing blood vessels. In contrast, vascular sprouting from placing the printed gel pattern perpendicular to pre-existing vessels resulted in deformation and structural disintegration of the original vasculature. We envision that this study will be useful to better understand angiogenesis-modulated neovascularization and further improve the treatment quality for various wounds and tissue defects. PMID:25450405

  17. 3D Modeling of branching vessels from anatomical sketches: towards a new interactive teaching of anatomy: Interactive virtual blackboard.

    PubMed

    Palombi, O; Pihuit, A; Cani, M-P

    2011-09-01

    Sketching is an intuitive way to explain spatial relationships between complex objects. The French community of Anatomists are used to teaching didactic lectures on a blackboard with their colored chalks. The increasing complexity of the sketches affords to the students an opportunity to work out a mental representation of anatomical structures in 3D. To help students perform this labored step, we present a new interactive blackboard which constructs plausible 3D models of branching vessels from a single sketch. We exploit the sketching conventions used in anatomical drawings to infer depth and curvature. We then model the set of branching vessels as a convolution surface generated by a graph of skeleton curves. Classic situations, focused on arteries, have been analyzed to manage vessels' curvatures, subdivisions and overlaps. Original sketches and 3D models are presented for each case. No specific training is required to use the interface. The anatomists have begun to embrace a new generation of 3D digital modeling applications as tools for anatomical teaching. We discuss the future use of this system as a step towards the interactive teaching of anatomy. PMID:21618014

  18. The promotion of endothelial progenitor cells recruitment by nerve growth factors in tissue-engineered blood vessels.

    PubMed

    Zeng, Wen; Yuan, Wei; Li, Li; Mi, Jianhong; Xu, Shangcheng; Wen, Can; Zhou, Zhenhua; Xiong, Jiaqiang; Sun, Jiansen; Ying, Dajun; Yang, Mingcan; Li, Xiaosong; Zhu, Chuhong

    2010-03-01

    Endothelial progenitor cells (EPCs) mobilization and homing are critical to the development of an anti-thrombosis and anti-stenosis tissue-engineered blood vessel. The growth and activation of blood vessels are supported by nerves. We investigated whether nerve growth factors (NGF) can promote EPCs mobilization and endothelialization of tissue-engineered blood vessels. In vitro, NGF promoted EPCs to form more colonies, stimulated human EPCs to differentiate into endothelial cells, and significantly enhanced EPCs migration. Flow cytometric analysis revealed that NGF treatment increased the number of EPCs in the peripheral circulation of C57BL/6 mice. Furthermore, the treatment of human EPCs with NGF facilitated their homing into wire-injured carotid arteries after injection into mice. Decellularized rat blood vessel matrix was incubated with EDC cross-linked collagen and bound to NGF protein using the bifunctional coupling agent N-succinmidyl3-(2-pyridyldit-hio) propionate (SPDP). The NGF-bound tissue-engineered blood vessel was implanted into rat carotid artery for 1 week and 1 month. NGF-bound blood vessels possessed significantly higher levels of endothelialization and patency than controls did. These results demonstrated that NGF can markedly increase EPCs mobilization and homing to vascular grafts. Neurotrophic factors such as NGF have a therapeutic potential for the construction of tissue-engineered blood vessels in vivo. PMID:20006381

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

    NASA Astrophysics Data System (ADS)

    Sills, Tiffany M.; Hirschi, Karen K.

    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.

  20. The degree of nonlinearity and anisotropy of blood vessel?elasticity

    PubMed Central

    Zhou, J.; Fung, Y. C.

    1997-01-01

    Blood vessel elasticity is important to physiology and clinical problems involving surgery, angioplasty, tissue remodeling, and tissue engineering. Nonlinearity in blood vessel elasticity in vivo is important to the formation of solitons in arterial pulse waves. It is well known that the stress–strain relationship of the blood vessel is nonlinear in general, but a controversy exists on how nonlinear it is in the physiological range. Another controversy is whether the vessel wall is biaxially isotropic. New data on canine aorta were obtained from a biaxial testing machine over a large range of finite strains referred to the zero-stress state. A new pseudo strain energy function is used to examine these questions critically. The stress–strain relationship derived from this function represents the sum of a linear stress–strain relationship and a definitely nonlinear relationship. This relationship fits the experimental data very well. With this strain energy function, we can define a parameter called the degree of nonlinearity, which represents the fraction of the nonlinear strain energy in the total strain energy per unit volume. We found that for the canine aorta, the degree of nonlinearity varies from 5% to 30%, depending on the magnitude of the strains in the physiological range. In the case of canine pulmonary artery in the arch region, Debes and Fung [Debes, J. C. & Fung, Y. C.(1995) Am. J. Physiol. 269, H433–H442] have shown that the linear regime of the stress–strain relationship extends from the zero-stress state to the homeostatic state and beyond. Both vessels, however, are anisotropic in both the linear and nonlinear regimes. PMID:9405599

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

    PubMed Central

    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

    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

  2. Direct imaging of singlet oxygen luminescence generated in blood vessels during photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Lin, Lisheng; Lin, Huiyun; Chen, Defu; Chen, Longchao; Wang, Min; Xie, Shusen; Gu, Ying; Wilson, Brian C.; Li, Buhong

    2014-05-01

    Singlet oxygen (1O2) is commonly recognized to be a major phototoxic component for inducing the biological damage during photodynamic therapy (PDT). In this study, a novel configuration of a thermoelectrically-cooled near-infrared sensitive InGaAs camera was developed for imaging of photodynamically-generated 1O2 luminescence. The validation of 1O2 luminescence images for solution samples was performed with the model photosensitizer Rose Bengal (RB). Images of 1O2 luminescence generated in blood vessels in vivo in a well-controlled dorsal skinfold window chamber model were also recorded during PDT. This study demonstrated the capacity of the newly-developed imaging system for imaging of 1O2 luminescence, and the first reported images of 1O2 luminescence in blood vessels in vivo. This system has potential for elucidating the mechanisms of vascular targeted PDT.

  3. Multiscale 3D Model of Platelet-Vessel Wall Interactions in Blood Flow

    E-print Network

    Wu, Ziheng; Alber, Mark

    2013-01-01

    Platelet adhesion to the injury site of the blood vessel wall is a critical step in blood clot formation and an important biomedical problem. Platelets aggregate at the injury site through tethering and rolling on the injured endothelium layer expressing surface-bound von Willebrand factor (vWF) during the initial stage of the blood clot formation. A three-dimensional multiscale model is introduced to simulate receptor-mediated platelet adhesion to substrate exposed with vWF under different shear rates of blood flow. The modeling approach combines Lattice Boltzmann method for simulating flow, hybrid cell membrane model to represent physiological elastic properties of a platelet and stochastic receptor-ligand binding model to describe biologically justified adhesion kinetics. Multiscale model is implemented on the GPUs cluster for speeding up simulations. The model is calibrated by comparing simulated adhesive properties of a platelet with the in vitro experimental data under different flow rates.

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

    E-print Network

    Freund, Jonathan B.

    exerted by the flowing blood. This force is particularly difficult to estimate due to the particulate. Effects of the particulate character of blood have been studied in detail for flow in small vessels (1­11), rolling of leuko- cytes (6,12), dynamics of vascular networks (13), and the design of blood microfluidic

  5. Relationship between Blood Flow Velocities in Retrobulbar Vessels and Laser Doppler Flowmetry at the Optic Disk in Glaucoma Patients

    Microsoft Academic Search

    Zuzana Bohdanecka; Selim Orgül; Anja B. Meyer; Christian Prünte; Josef Flammer

    1999-01-01

    The relationship between blood flow velocities in retrobulbar vessels and blood flow at the optic nerve in glaucoma patients was assessed in a prospective study. The Heidelberg retina flowmeter (HRF) was used to assess optic nerve head blood flow in 13 open-angle glaucoma patients. In the same patients, color Doppler imaging (CDI) measurements were obtained from the ophthalmic artery, the

  6. Dual-body magnetic helical robot for drilling and cargo delivery in human blood vessels

    NASA Astrophysics Data System (ADS)

    Lee, Wonseo; Jeon, Seungmun; Nam, Jaekwang; Jang, Gunhee

    2015-05-01

    We propose a novel dual-body magnetic helical robot (DMHR) manipulated by a magnetic navigation system. The proposed DMHR can generate helical motions to navigate in human blood vessels and to drill blood clots by an external rotating magnetic field. It can also generate release motions which are relative rotational motions between dual-bodies to release the carrying cargos to a target region by controlling the magnitude of an external magnetic field. Constraint equations were derived to selectively manipulate helical and release motions by controlling external magnetic fields. The DMHR was prototyped and various experiments were conducted to demonstrate its motions and verify its manipulation methods.

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

    PubMed

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

    2011-07-01

    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. PMID:21806238

  8. alpha-Tocopherol increased nitric oxide synthase activity in blood vessels of spontaneously hypertensive rats.

    PubMed

    Newaz, M A; Nawal, N N; Rohaizan, C H; Muslim, N; Gapor, A

    1999-08-01

    Antioxidant protection provided by different doses of alpha-tocopherol was compared by determining nitric oxide synthase (NOS) activity in blood vessels of spontaneously hypertensive rats (SHR) treated with alpha-tocopherol. SHR were divided into four groups namely hypertensive control (C), treatment with 17 mg of alpha-tocopherol/kg diet (alpha1), 34 mg of alpha-tocopherol/kg diet (alpha2), and 170 mg of alpha-tocopherol/kg diet (alpha3). Wister Kyoto (WKY) rats were used as normal control (N). Blood pressure were recorded from the tail by physiography every other night for the duration of the study period of 3 months. At the end of the trial, animals were sacrificed. The NOS activity in blood vessels was measured by [3H]arginine radioactive assay and the nitrite concentration in plasma by spectrophotometry at wavelength 554 nm using Greiss reagent. Analysis of data was done using Student's t test and Pearson's correlation. The computer program Statistica was used for all analysis. Results of our study showed that for all the three alpha-tocopherol-treated groups, blood pressure was significantly (P < .001) reduced compared to the hypertensive control and maximum reduction of blood pressure was shown by the dosage of 34 mg of alpha-tocopherol/kg diet (C: 209.56 +/- 8.47 mm Hg; alpha2: 128.83 +/- 17.13 mm Hg). Also, NOS activity in blood vessels of SHR was significantly lower than WKY rats (N: 1.54 +/- 0.26 pmol/mg protein, C: 0.87 +/- 0.23 pmol/mg protein; P < .001). Although alpha-tocopherol in doses of alpha1, alpha2, and alpha3 increased the NOS activity in blood vessels, after treatment only that of alpha2 showed a statistical significance (P < .01). Plasma nitrite concentration was significantly reduced in SHR compared to normal WKY rats (N: 54.62 +/- 2.96 mol/mL, C: 26.24 +/- 2.14 mol/mL; P < .001) and accordingly all three groups showed significant improvement in their respective nitrite level (P < .001). For all groups, NOS activity and nitrite level showed negative correlation with blood pressure. It was significant for NOS activity in hypertensive control (r = -0.735, P = .038), alpha1 (r = -0.833, P = .001), and alpha2 (r = -0.899, P = .000) groups. For plasma nitrite, significant correlation was observed only in group alpha1 (r = -0.673, P = .016) and alpha2 (r = -0.643, P = .024). Only the alpha2 group showed significant positive correlation (r = 0.777, P = .003) between NOS activity and nitrite level. In conclusion it was found that compared to WKY rats, SHR have lower NOS activity in blood vessels, which upon treatment with antioxidant alpha-tocopherol increased the NOS activity and concomitantly reduced the blood pressure. There was correlation of lipid peroxide in blood vessels with NOS and nitric oxide, which implies that free radicals may be involved in the pathogenesis of hypertension. PMID:10480480

  9. Composite Fibrin Scaffolds Increase Mechanical Strength and Preserve Contractility of Tissue Engineered Blood Vessels

    Microsoft Academic Search

    Lan Yao; Jinyu Liu; Stelios T. Andreadis

    2008-01-01

    Objectives  We recently demonstrated that fibrin-based tissue engineered blood vessels (TEV) exhibited vascular reactivity, matrix remodeling\\u000a and sufficient strength for implantation into the veins of an ovine animal model, where they remained patent for 15 weeks.\\u000a Here we present an approach to improve the mechanical properties of fibrin-based TEV and examine the relationship between\\u000a mechanical strength and smooth muscle cell (SMC) function.

  10. Vascular Endothelial Growth Factor and Its Receptors in Embryonic Zebrafish Blood Vessel Development

    Microsoft Academic Search

    Katsutoshi Goishi; Michael Klagsbrun

    2004-01-01

    There is intense interest in how blood vessel development is regulated. A number of vascular growth factors and their receptors have been described. The vascular endothelial growth factor (VEGF) and its receptors are major contributors to normal mammalian vascular development. These receptors include VEGFR-1, VEGFR-2, VEGFR-3, neuropilin-1 (NRP1), and NRP2. The function of these genes have been determined to some

  11. Elastin biosynthesis: The missing link in tissue-engineered blood vessels

    Microsoft Academic Search

    Alpesh Patel; Benjamin Fine; Martin Sandig; Kibret Mequanint

    2006-01-01

    Abstract Nearly 20years have passed since Weinberg and Bell attempted to make,the first tissue-engineered blood vessels. Following this early attempt, vascular tissue engineering has emerged as one of the most promising approaches to fabricate orderly and mechanically competent vascular substitutes. In elastic and muscular arteries, elastin is a critical structural and regulatory matrix protein and plays an important and dominant,role

  12. Two-compartment model for plasma pharmacokinetics in individual blood vessels

    Microsoft Academic Search

    Lawrence J. Nugent; Rakesh K. Jain

    1984-01-01

    Plasma pharmacokinetics of sodium fluorescein, fluorescein isothiocyanate conjugated bovine serum albumin, and a graded series of dextrans of 19,400 to 71,800 MW were monitored continuously using a noninvasive photometric technique in individual blood vessels of tissue grown in a rabbit ear chamber. The data obtained were fitted with a two-compartment open model to obtain an effective permeability and an effective

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

    PubMed Central

    Andrews, C J; Andrews, W H

    1976-01-01

    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 PMID:1002604

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

    SciTech Connect

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

    1990-01-01

    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.

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

    PubMed

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

    2014-07-01

    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

  16. Blood vessel wall-derived endothelial colony-forming cells enhance fracture repair and bone regeneration.

    PubMed

    Chandrasekhar, Kaarthik S; Zhou, Hongkang; Zeng, Pingyu; Alge, Daniel; Li, Wenyao; Finney, Brandt A; Yoder, Mervin C; Li, Jiliang

    2011-11-01

    Endochondral bone formation requires new blood vessel formation, and endothelial progenitor cells (EPCs) may play a role in this process. Endothelial colony-forming cells (ECFCs), one subtype of EPCs, isolated from the microvasculature of rat lungs, exhibited cell surface antigen markers and gene products characteristic of endothelial cells and displayed high proliferative potential and an ability to form vessel-like network structures in vitro. The aim of this study was to evaluate whether ECFCs facilitate bone healing during fracture repair and stimulate bone regeneration. When type I collagen sponge containing ECFCs were surgically wrapped around the fractured femurs of rats, newly formed bone mineral at the site of fracture was 13% greater (P = 0.01) and energy to failure was 46% greater (P = 0.01) compared to sponge-wrapped fractures without ECFCs. When ECFCs in type I collagen sponge were surgically implanted into the bone defective area, more new vessels formed locally in comparison with sponge-alone controls and new bone tissues were seen. Further, co-implantation of ECFCs and hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds at the bone defective sites stimulated more new bone tissues than HA/TCP scaffold alone. These results show that cell therapy with vessel wall-derived ECFCs can induce new vessel formation, stimulate new bone formation, and facilitate bone repair and could be a useful approach to treat non-union fractures and bone defects. PMID:21882012

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

    PubMed Central

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

    2011-01-01

    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. PMID:21931602

  18. Optic nerve lesions in diabetic rats: blood flow to the optic nerve, permeability of micro blood vessels and histopathology

    PubMed Central

    Zhao, Jun-Ping; Ma, Zhi-Zhong; Song, Chen; Li, Xiang-Hong; Li, Yu-Zhen; Liu, Yu-Ying

    2010-01-01

    AIM To study optic nerve lesions, changes in blood flow to the optic nerve, and permeability of micro blood vessels and histopathology in diabetic rats. METHODS Male Wistar rats (n=20) were randomly divided into control and diabetic groups. The diabetic model was prepared by a single injection of streptozotocin (50mg/kg) into the caudal vein. Three months later, laser Doppler perfusion imaging was used to observe the changes in blood flow to the optic nerve. Each rat was injected with 15g/L Evans blue (5µL/g). The permeability of microvessels in diabetic optic nerves was measured by spectrophotometry. Optic nerves were observed by light and transmission electron microscopy. RESULTS Diabetic rats had atrophic optic nerve fibers with neurite swelling, loss of myelin, and a greater-than-normal proliferation of astrocytes, occurring within 3 months of induction of diabetes. Blood flow to the optic nerve was lower in diabetic rats than in controls. Microvessel permeability in diabetic rats increased 2.03-fold compared to controls. CONCLUSION Diabetic rats develop significant pathological changes in the optic nerve, reduced blood flow to the optic nerve and increase microvessel permeability. PMID:22553576

  19. Drug that blocks blood vessel growth may be beneficial in treating AIDS-related Kaposi’s sarcoma

    Cancer.gov

    Patients with an AIDS-associated cancer, Kaposi's sarcoma (KS), showed improvement after receiving the combination of bevacizumab, a cancer drug that blocks the growth of new blood vessels, and highly active antiretroviral therapy (HAART).

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

    PubMed Central

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

    2013-01-01

    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

  1. Where do the platelets go? A simulation study of fully resolved blood flow through aneurysmal vessels

    PubMed Central

    Mountrakis, L.; Lorenz, E.; Hoekstra, A. G.

    2013-01-01

    Despite the importance of platelets in the formation of a thrombus, their transport in complex flows has not yet been studied in detail. In this paper we simulated red blood cells and platelets to explore their transport behaviour in aneurysmal geometries. We considered two aneurysms with different aspect ratios (AR = 1.0, 2.0) in the presence of fast and slow blood flows (Re = 10, 100), and examined the distributions of the cells. Low velocities in the parent vessel resulted in a large stagnation zone inside the cavity, leaving the initial distribution almost unchanged. In fast flows, an influx of platelets into the aneurysm was observed, leading to an elevated concentration. The connection of the platelet-rich cell-free layer (CFL) with the outer regions of the recirculation zones leads to their increased platelet concentration. These platelet-enhanced recirculation zones produced a diverse distribution of cells inside the aneurysm, for the different aspect ratios. A thin red blood CFL that was occupied by platelets was observed on the top of the wide-necked aneurysm, whereas a high-haematocrit region very close to the vessel wall was present in the narrow-necked case. The simulations revealed that non-trivial distributions of red blood cells and platelets are possible inside aneurysmal geometries, giving rise to several hypotheses on the formation of a thrombus, as well as to the wall weakening and the possible rupture of an aneurysm. PMID:24427532

  2. Thin and open vessel windows for intra-vital fluorescence imaging of murine cochlear blood flow.

    PubMed

    Shi, Xiaorui; Zhang, Fei; Urdang, Zachary; Dai, Min; Neng, Lingling; Zhang, Jinhui; Chen, Songlin; Ramamoorthy, Sripriya; Nuttall, Alfred L

    2014-07-01

    Normal microvessel structure and function in the cochlea is essential for maintaining the ionic and metabolic homeostasis required for hearing function. Abnormal cochlear microcirculation has long been considered an etiologic factor in hearing disorders. A better understanding of cochlear blood flow (CoBF) will enable more effective amelioration of hearing disorders that result from aberrant blood flow. However, establishing the direct relationship between CoBF and other cellular events in the lateral wall and response to physio-pathological stress remains a challenge due to the lack of feasible interrogation methods and difficulty in accessing the inner ear. Here we report on new methods for studying the CoBF in a mouse model using a thin or open vessel-window in combination with fluorescence intra-vital microscopy (IVM). An open vessel-window enables investigation of vascular cell biology and blood flow permeability, including pericyte (PC) contractility, bone marrow cell migration, and endothelial barrier leakage, in wild type and fluorescent protein-labeled transgenic mouse models with high spatial and temporal resolution. Alternatively, the thin vessel-window method minimizes disruption of the homeostatic balance in the lateral wall and enables study CoBF under relatively intact physiological conditions. A thin vessel-window method can also be used for time-based studies of physiological and pathological processes. Although the small size of the mouse cochlea makes surgery difficult, the methods are sufficiently developed for studying the structural and functional changes in CoBF under normal and pathological conditions. PMID:24780131

  3. Simulations of localized harmonic motions on a blood vessel wall induced by an acoustic radiation force used in ultrasound elastography

    Microsoft Academic Search

    Janne Heikkilä; Tero Karjalainen; Marko Vauhkonen; Kullervo Hynynen

    2006-01-01

    Many noninvasive techniques have been developed recently to explore the mechanical properties of soft tissue. In this paper, dynamic acoustic radiation force induced vibrations on a blood vessel wall were simulated using different stimulation frequencies and stiffness parameters for the vessel wall. The stimulation frequency was varied between 20 Hz and 20 kHz and the stiffness parameter (Young's modulus) was

  4. Blood Vessel Classification into Arteries and Veins in Retinal Claudia Kondermann and Daniel Kondermanna and Michelle Yanb

    E-print Network

    Cremers, Daniel

    Blood Vessel Classification into Arteries and Veins in Retinal Images Claudia Kondermann and Daniel for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins

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

    NASA Astrophysics Data System (ADS)

    Kol, Guy Richard; Bertrand Tabi, Conrad

    2011-04-01

    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.

  6. A Computational Model of Micro-Bubble-Induced Blood Vessel Deformation in Gas Embolotherapy

    NASA Astrophysics Data System (ADS)

    Ye, Tao; Bull, Joseph L.

    2004-11-01

    Gas embolotherapy is a potential cancer treatment modality that involves injecting liquid perfluorocarbon droplets into the vasculature, and using ultrasound to vaporize the droplets to form larger gas bubbles that can then embolize tumors. The rapid volume expansion during the droplet vaporization may potentially rupture blood vessels. In previous work, we have presented results for the wall stresses in the vaporization process assuming the vessel wall is rigid. In this study, we present a computational model of a bubble expansion in a long tube with an elastic wall to model the flexibility of blood vessels. Deformations of the tube wall and the interface are determined as part of the solution. The unsteady Navier-Stokes equations are solved using a sharp-interface, moving boundary, finite-volume method. Tube wall expansion due to the bubble expansion results in an in flow of liquid at the open ends of the tube. The liquid in the vicinity of the bubble, however, moves in the opposite direction because of the bubble expansion. The two counteracting mechanisms create a complex flow pattern in the tube. The time-dependent wall stresses are also investigated to assess the potential for wall damage. This work is supported by NIH grant EB003541-01 and NSF grant BES-0301278.

  7. Regulation of Cellular Communication by Signaling Microdomains in the Blood Vessel Wall

    PubMed Central

    Billaud, Marie; Lohman, Alexander W.; Johnstone, Scott R.; Biwer, Lauren A.; Mutchler, Stephanie; Isakson, Brant E.

    2014-01-01

    It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function. PMID:24671377

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

    PubMed

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

    2013-03-01

    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

  9. Effect of a soluble surfactant on a finite sized bubble motion in a blood vessel

    PubMed Central

    Swaminathan, T. N.; Mukundakrishnan, K.; Ayyaswamy, P. S.; Eckmann, D. M.

    2009-01-01

    We present detailed results for the motion of a finite sized gas bubble in a blood vessel. The bubble (dispersed phase) size is taken to be such as to nearly occlude the vessel. The bulk medium is treated as a shear thinning Casson fluid and contains a soluble surfactant that adsorbs and desorbs from the interface. Three different vessel sizes, corresponding to a small artery, a large arteriole, and a small arteriole, in normal humans, are considered. The hematocrit (volume fraction of RBCs) has been taken to be 0.45. For arteriolar flow, where relevant, the Fahraeus-Lindqvist effect is taken into account. Bubble motion cause temporal and spatial gradients of shear stress at the cell surface lining the vessel wall as the bubble approaches the cell, moves over it and passes it by. Rapid reversals occur in the sign of the shear stress imparted to the cell surface during this motion. Shear stress gradients together with sign reversals are associated with a recirculation vortex at the rear of the moving bubble. The presence of the surfactant reduces the level of the shear stress gradients imparted to the cell surface as compared to an equivalent surfactant-free system. Our numerical results for bubble shapes and wall shear stresses may help explain phenomena observed in experimental studies related to gas embolism, a significant problem in cardiac surgery and decompression sickness. PMID:20305744

  10. Understanding How Space Travel Affects Blood Vessels: Arterial Remodeling and Functional Adaptations Induced by Microgravity

    NASA Technical Reports Server (NTRS)

    Delp, Michael; Vasques, Marilyn; Aquilina, Rudy (Technical Monitor)

    2002-01-01

    Ever rise quickly from the couch to get something from the kitchen and suddenly feel dizzy? With a low heart rate and relaxed muscles, the cardiovascular system does not immediately provide the resistance necessary to keep enough blood going to your head. Gravity wins, at least for a short time, before your heart and blood vessels can respond to the sudden change in position and correct the situation. Actually, the human cardiovascular system is quite well adapted to the constant gravitational force of the Earth. When standing, vessels in the legs constrict to prevent blood from collecting in the lower extremities. In the space environment, the usual head-to-foot blood pressure and tissue fluid gradients that exist during the upright posture on Earth are removed. The subsequent shift in fluids from the lower to the upper portions of the body triggers adaptations within the cardiovascular system to accommodate the new pressure and fluid gradients. In animal models that simulate microgravity, the vessels in the head become more robust while those in the lower limbs become thin and lax. Similar changes may also occur in humans during spaceflight and while these adaptations are appropriate for a microgravity environment, they can cause problems when the astronauts return to Earth or perhaps another planet. Astronauts often develop orthostatic intolerance which means they become dizzy or faint when standing upright. This dizziness can persist for a number of days making routine activities difficult. In an effort to understand the physiological details of these cardiovascular adaptations, Dr. Michael Delp at Texas A&M University, uses the rat as a model for his studies. For the experiment flown on STS-107, he will test the hypothesis that blood vessels in the rats' hindlimbs become thinner, weaker, and constrict less in response to pressure changes and to chemical signals when exposed to microgravity. In addition, he will test the hypothesis that arteries in the brain become thicker as a result of microgravity-induced fluid shifts toward the head.

  11. Use of anatomical knowledge to register 3-D blood vessel data derived from DSA with MR images

    NASA Astrophysics Data System (ADS)

    Hill, Derek L.; Hawkes, David J.; Hardingham, Charles R.

    1991-06-01

    We propose a new algorithm for registering 3D reconstructions of blood vessels from DSA with MR images of the brain. The registration transformation is determined by fitting the blood vessel tree reconstructed from DSA projections into the fissures of the brain derived from MR images, somewhat in the manner of fitting a key into a lock. The fit of the vessels into the fissures is guided by specific but simple anatomical knowledge. Preliminary evaluation of the algorithm has been carried out using data derived from a cadaver brain.

  12. Tissue-engineered blood vessels as promising tools for testing drug toxicity.

    PubMed

    Truskey, George A; Fernandez, Cristina E

    2015-07-01

    Drug-induced vascular injury (DIVI) is a serious problem in preclinical studies of vasoactive molecules and for survivors of pediatric cancers. DIVI is often observed in rodents and some larger animals, primarily with drugs affecting vascular tone, but not in humans; however, DIVI observed in animal studies often precludes a drug candidate from continuing along the development pipeline. Thus, there is great interest by the pharmaceutical industry to identify quantifiable human biomarkers of DIVI. Small-scale endothelialized tissue-engineered blood vessels using human cells represent a promising approach to screen drug candidates and develop alternatives to cancer therapeutics in vitro. We identify several technical challenges that remain to be addressed, including high-throughput systems to screen large numbers of candidates, identification of suitable cell sources and establishing and maintaining a differentiated state of the vessel wall cells. Adequately addressing these challenges should yield novel platforms to screen drugs and develop new therapeutics to treat cardiovascular disease. PMID:26028128

  13. Simulations of Blood Flow in Plain Cylindrical and Constricted Vessels with Single Cell Resolution

    E-print Network

    Florian Janoschek; Federico Toschi; Jens Harting

    2011-05-31

    Understanding the physics of blood is challenging due to its nature as a suspension of soft particles and the fact that typical problems involve different scales. This is valid also for numerical investigations. In fact, many computational studies either neglect the existence of discrete cells or resolve relatively few cells very accurately. The authors recently developed a simple and highly efficient yet still particulate model with the aim to bridge the gap between currently applied methods. The present work focuses on its applicability to confined flows in vessels of diameters up to 100 micrometres. For hematocrit values below 30 percent, a dependence of the apparent viscosity on the vessel diameter in agreement with experimental literature data is found.

  14. Mechanisms of ATP release and signalling in the blood vessel wall

    PubMed Central

    Lohman, Alexander W.; Billaud, Marie; Isakson, Brant E.

    2012-01-01

    The nucleotide adenosine 5?-triphosphate (ATP) has classically been considered the cell's primary energy currency. Importantly, a novel role for ATP as an extracellular autocrine and/or paracrine signalling molecule has evolved over the past century and extensive work has been conducted to characterize the ATP-sensitive purinergic receptors expressed on almost all cell types in the body. Extracellular ATP elicits potent effects on vascular cells to regulate blood vessel tone but can also be involved in vascular pathologies such as atherosclerosis. While the effects of purinergic signalling in the vasculature have been well documented, the mechanism(s) mediating the regulated release of ATP from cells in the blood vessel wall and circulation are now a key target of investigation. The aim of this review is to examine the current proposed mechanisms of ATP release from vascular cells, with a special emphasis on the transporters and channels involved in ATP release from vascular smooth muscle cells, endothelial cells, circulating red blood cells, and perivascular sympathetic nerves, including vesicular exocytosis, plasma membrane F1/F0-ATP synthase, ATP-binding cassette (ABC) transporters, connexin hemichannels, and pannexin channels. PMID:22678409

  15. Correlation mapping method of OCT for visualization blood vessels in brain

    NASA Astrophysics Data System (ADS)

    Izotova, O. A.; Kalyanov, A. L.; Lychagov, V. V.; Semyachkina-Glushkovskaya, O. V.

    2013-11-01

    The burning issue in modern medicine is the diagnosis and treatment of various life-threatening diseases, in particular the diseases of brain. One of them is intracranial hemorrhage (ICH). It occurs especially among newborn babies and is hard-diagnosed. In order to understand the nature of the ICH, the microcirculation of blood, which serves key functions within the body, is analyzed. On this basis a series of experiments was done, in the results of which it was showed, that latent stage of ICH is characterized by decrease of venous blood outflow and the loss of sensitivity of sagittal vein to vasoconstrictor effect of adrenaline. So, stress-related changes of the cerebral venous blood flow (CVBF) can be the source of this disease. In this paper registration CVBF was made with the help of commercially available Thorlabs Swept Source OCT System, using the correlation mapping method. In this method values of correlation coefficient of several images are analyzed. In the result of the algorithm the correlation map was obtained. By the resulting map the diameter of vessels was calculated, which is necessary for examination of effects of adrenalin to the vessels and identification symptoms of ICH.

  16. Measurement of contrast of phantom and in vivo subsurface blood vessels using two near-infrared imaging systems

    NASA Astrophysics Data System (ADS)

    Hebden, Jeremy C.; Alkhaja, Aysha; Mahe, Laure; Powell, S.; Everdell, N. L.

    2015-03-01

    A quantitative comparison has been performed between two commercial near-infrared (NIR) vein-viewing systems which are designed to supplement the clinician's traditional skills in locating veins by means of visualization and palpation. The AccuVein AV300 and Novarix IV-eye real-time imaging systems employ very different imaging geometries; the former generates an image from reflected NIR light produced by a beam scanned across the surface, while the latter illuminates the viewed region at four points on the periphery and records the resulting distribution of diffusely transmitted light. The comparison involved measuring the contrast produced by absorbing rods (simulated blood vessels) in a cylindrical phantom with tissue-like optical properties, and the contrast of superficial blood vessels in the arms of healthy volunteers. The locations and sizes of the blood vessels were independently verified using a clinical ultrasound imaging system. The phantom measurements suggested that the AV300 displays the most superficial vessels with greater contrast, but the IV-eye is able to detect vessels when they are at a depth up to 2 mm greater than the limit observed for the AV300. The results for thirty healthy volunteers also indicated that the AV300 typically displays vessels with higher overall contrast, but the effectiveness of the IV-eye at visualizing deeper vessels was even more pronounced, with a maximum depth several millimeters greater than that achieved by the AV300, and more than ten times as many vessels observed at depths below 4 mm.

  17. The effect of complex exercise rehabilitation program on body composition, blood pressure, blood sugar, and vessel elasticity in elderly women with obesity

    PubMed Central

    Lee, Eun-Ok; Lee, Kwon-Ho; Kozyreva, Olga

    2013-01-01

    The purpose of this study is to identify what kind of effects complex exercise rehabilitation program has on body composition of female, blood pressure, blood sugar, blood vessel elasticity and find more effective complex exercise program for elderly females. The subjects are selected 30 females applicants in exercise program in City of G and not restricted in mobility to perform the exercise without any particular disorders. Exercise program is a combination of aerobic and strength training with different ratio, for the first 6 months focused on strength training complex exercise, and for next 6 months focused on aerobic exercise. Except for strength training and aerobic exercise, durations for strength, rest, and wrapping-up are equal. The frequency of experiments is 90 min each, 2 times per a week. Body composition, blood pressure, and blood vessel elasticity are tested pre and post experiment to compare the effectiveness of both complex exercises. As results, in the complex exercise program focused on strength training, weight, percent body fat, fat mass, waist hip ratio, systolic blood pressure, and diastolic pressure increased. Blood vessel elasticity maintained its level or slightly decreased. In the complex exercise focused on aerobic exercise, weight, percent body fat, fat mass, waist hip ratio, systolic pressure, and diastolic pressure decreased. Blood vessel elasticity on left foot and right foot are slightly different. Therefore, aerobic exercise is more effective than strength training for old obese females. PMID:24409428

  18. Tauroursodeoxycholic acid, a bile acid, promotes blood vessel repair by recruiting vasculogenic progenitor cells.

    PubMed

    Cho, Jin Gu; Lee, Jun Hee; Hong, Shin Hee; Lee, Han Na; Kim, Chul Min; Kim, Seo Yoon; Yoon, Kang Jun; Oh, Bae Jun; Kim, Jae Hyeon; Jung, Seok Yoon; Asahara, Takayuki; Kwon, Sang-Mo; Park, Sang Gyu

    2015-03-01

    Although serum bile acid concentrations are approximately 10 µM in healthy subjects, the crosstalk between the biliary system and vascular repair has never been investigated. In this study, tauroursodeoxycholic acid (TUDCA) induced dissociation of CD34(+) hematopoietic stem cells (HSCs) from stromal cells by reducing adhesion molecule expression. TUDCA increased CD34(+) /Sca1(+) progenitors in mice peripheral blood (PB), and CD34(+) , CD31(+) , and c-kit(+) progenitors in human PB. In addition, TUDCA increased differentiation of CD34(+) HSCs into EPC lineage cells via Akt activation. EPC invasion was increased by TUDCA, which was mediated by fibroblast activating protein via Akt activation. Interestingly, TUDCA induced integration of EPCs into human aortic endothelial cells (HAECs) by increasing adhesion molecule expression. In the mouse hind limb ischemia model, TUDCA promoted blood perfusion by enhancing angiogenesis through recruitment of Flk-1(+) /CD34(+) and Sca-1(+) /c-kit(+) progenitors into damaged tissue. In GFP(+) bone marrow-transplanted hind limb ischemia, TUDCA induced recruitment of GFP(+) /c-kit(+) progenitors to the ischemic area, resulting in an increased blood perfusion ratio. Histological analysis suggested that GFP(+) progenitors mobilized from bone marrow, integrated into blood vessels, and differentiated into VEGFR(+) cells. In addition, TUDCA decreased cellular senescence by reducing levels of p53, p21, and reactive oxygen species and increased nitric oxide. Transplantation of TUDCA-primed senescent EPCs in hind limb ischemia significantly improved blood vessel regeneration, as compared with senescent EPCs. Our results suggested that TUDCA promoted neovascularization by enhancing the mobilization of stem/progenitor cells from bone marrow, their differentiation into EPCs, and their integration with preexisting endothelial cells. PMID:25407160

  19. Launch Conditions Might Affect the Formation of Blood Vessel in the Quail Chorioallantoic Membrane

    NASA Technical Reports Server (NTRS)

    Henry, M. K.; Unsworth, B. R.; Sychev, B. R.; 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

    AS 2 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 embryos exposed to vibrational and g-forces simulating the conditions experienced during the launch of Progress 227. We hypothesized that excess mechanical forces and/or other conditions during the launch might cause abnormal development of 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 or 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 angiogenesis In the CAM might contribute to the impaired survival of the embryos observed in synchronous controls as well as in space.

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

    SciTech Connect

    Roberts, R.E., E-mail: Richard.roberts@nottingham.ac.uk; 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., E-mail: steve.alexander@nottingham.ac.uk

    2013-11-01

    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. - Highlights: • Apigenin, luteolin, and (-)-?-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These relaxations were associated with an inhibition of calcium entry. • Farnesene, at concentrations up to 30 ?M, was without effect in either blood vessel. • Umbelliferone produced a rapid, transient nitric oxide-dependent relaxation.

  1. Limitations of quantitative photoacoustic measurements of blood oxygenation in small vessels.

    PubMed

    Sivaramakrishnan, Mathangi; Maslov, Konstantin; Zhang, Hao F; Stoica, George; Wang, Lihong V

    2007-03-01

    We investigate the feasibility of obtaining accurate quantitative information, such as local blood oxygenation level (sO2), with a spatial resolution of about 50 microm from spectral photoacoustic (PA) measurements. The optical wavelength dependence of the peak values of the PA signals is utilized to obtain the local blood oxygenation level. In our in vitro experimental models, the PA signal amplitude is found to be linearly proportional to the blood optical absorption coefficient when using ultrasonic transducers with central frequencies high enough such that the ultrasonic wavelengths are shorter than the light penetration depth into the blood vessels. For an optical wavelength in the 578-596 nm region, with a transducer central frequency that is above 25 MHz, the sensitivity and accuracy of sO2 inversion is shown to be better than 4%. The effect of the transducer focal position on the accuracy of quantifying blood oxygenation is found to be negligible. In vivo oxygenation measurements of rat skin microvasculature yield results consistent with those from in vitro studies, although factors specific to in vivo measurements, such as the spectral dependence of tissue optical attenuation, dramatically affect the accuracy of sO2 quantification in vivo. PMID:17301459

  2. A Pulsatile Flow Phantom for Image-Guided HIFU Hemostasis of Blood Vessels

    SciTech Connect

    Greaby, Robyn; Vaezy, Shahram [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, Seattle, WA 98195 (United States); Department of Bioengineering, University of Washington, Seattle, WA 98195 (United States)

    2005-03-28

    A pulsatile flow phantom for studying ultrasound image-guided acoustic hemostasis in a controlled environment has been developed. An ex vivo porcine carotid artery was attached to the phantom and embedded in a visually and ultrasonically transparent gel. Heparinized porcine blood was pumped through the phantom. Power-Doppler and B-mode ultrasound were used to remotely target the HIFU focus to the site of a needle puncture. In nine trials, complete hemostasis was achieved after an average HIFU application of 55 +/- 34 seconds. The vessels remained patent after treatment. With this phantom, it will be possible to do controlled studies of ultrasound image-guided acoustic hemostasis.

  3. [Use of Polish synthetic latex LBS 3041 for anatomical studies of blood and lymphatic vessels].

    PubMed

    Stefanowski, T; Doboszy?ska, T; Janowicz, K; Zamojska, D

    1979-01-01

    The Polish synthetic latex LBS 3041 produced in Chemical Works "O?wiecim" was examined for anatomical purposes. The latex was stained with pigments "Vulkan", pasts of general use "Pastokol" and commercial pigments to emulsive dyes. There was established a much better penetration into small blood vessels by latex LBS 3041 than by latex LBS 3060. On the account of the resistance of the examined latex to the coagulating activity of acetic acid, the hardening of the stuff after the injection of the specimens occurs through the cooling of preparations in the refrigerator. PMID:548937

  4. Blood vessels and the occurrence of arteriovenous anastomoses in cephalic heat loss areas of mallards, Anas platyrhynchos (Aves)

    Microsoft Academic Search

    Uffe Midtgård

    1984-01-01

    1. The blood supply to cephalic heat loss areas (nasal and oropharyngeal mucosa, bill, eyelids) was studied in mallards by using plastic corrosion casts. The structure and organization of the blood vessels, as well as the occurrence of arteriovenous anastomoses (AVAs), were examined by scanning electron microscopy of vascular casts and by paraffin sections.

  5. Refining the 3D surface of blood vessels from a reduced set of 2D DSA images

    E-print Network

    Paris-Sud XI, Université de

    high quality of 3D vascular imaging modalities, artifacts and noise still hamper the extraction is a localized blood-filled dilation of a blood vessel that may occasionally rupture, causing hemorrhage, stroke of 3D vascular imaging modalities, artifacts and noise still hamper the extraction of this surface

  6. 3D Computer Simulations of Pulsatile Human Blood Flows in Vessels and in the Aortic Arch: Investigation of Non-Newtonian Characteristics of Human Blood

    E-print Network

    Sultanov, Renat A; Engelbrekt, Brent; Blankenbecler, Richard

    2008-01-01

    Methods of Computational Fluid Dynamics are applied to simulate pulsatile blood flow in human vessels and in the aortic arch. The non-Newtonian behaviour of the human blood is investigated in simple vessels of actual size. A detailed time-dependent mathematical convergence test has been carried out. The realistic pulsatile flow is used in all simulations. Results of computer simulations of the blood flow in vessels of two different geometries are presented. For pressure, strain rate and velocity component distributions we found significant disagreements between our results obtained with realistic non-Newtonian treatment of human blood and widely used method in literature: a simple Newtonian approximation. A significant increase of the strain rate and, as a result, wall sear stress distribution, is found in the region of the aortic arch. We consider this result as theoretical evidence that supports existing clinical observations and those models not using non-Newtonian treatment underestimate the risk of disru...

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

    NASA Astrophysics Data System (ADS)

    Zhang, Minghui; Brazel, Christopher

    2011-11-01

    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. Funded by NSF REU Site #1062611.

  8. The Effects of Impact Vibration on Peripheral Blood Vessels and Nerves

    PubMed Central

    KRAJNAK, Kristine M.; WAUGH, Stacey; JOHNSON, Claud; MILLER, G. Roger; XU, Xueyan; WARREN, Christopher; DONG, Ren G.

    2013-01-01

    Research regarding the risk of developing hand-arm vibration syndrome after exposure to impact vibration has produced conflicting results. This study used an established animal model of vibration-induced dysfunction to determine how exposure to impact vibration affects peripheral blood vessels and nerves. The tails of male rats were exposed to a single bout of impact vibration (15 min exposure, at a dominant frequency of 30?Hz and an unweighted acceleration of approximately 345 m/s2) generated by a riveting hammer. Responsiveness of the ventral tail artery to adrenoreceptor-mediated vasoconstriction and acetylcholine-mediated re-dilation was measured ex vivo. Ventral tail nerves and nerve endings in the skin were assessed using morphological and immunohistochemical techniques. Impact vibration did not alter vascular responsiveness to any factors or affect trunk nerves. However, 4 days following exposure there was an increase in protein-gene product (PGP) 9.5 staining around hair follicles. A single exposure to impact vibration, with the exposure characteristics described above, affects peripheral nerves but not blood vessels. PMID:24077447

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

    PubMed

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

    2012-05-01

    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

  10. A parallel two-level method for simulating blood flows in branching arteries with the resistive boundary condition q

    E-print Network

    Cai, Xiao-Chuan

    A parallel two-level method for simulating blood flows in branching arteries with the resistive modeling of blood flows in the arteries is an important and very challenging problem. In order to understand, computationally, the sophisticated hemodynamics in the arteries, it is essential to couple

  11. Basic study for diagnosing blood vessel plaque employing ultrasonic velocity-change imaging in combination with near-infrared illumination

    NASA Astrophysics Data System (ADS)

    Mano, Kazune; Tanigawa, Shohei; Wada, Kenji; Matsunaka, Toshiyuki; Horinaka, Hiromichi

    2015-05-01

    It is important to detect unstable blood vessel plaques at an early stage to prevent their detachment and subsequent myocardial or brain infarctions. The instability of such plaques depends on the size and distribution of the internal lipid core. We propose a method for identifying lipid domains by changes in the ultrasound propagation velocity after warming with a near-infrared laser. First, we demonstrate that the most effective warming of fatty tissue to induce ultrasonic velocity changes is with a 935-nm laser. Next, a compliant blood vessel phantom containing an internal lipid domain was constructed and attached to a pulsatile pump. Experiments showed that the lipid domain could be identified with ultrasonic velocity-change imaging even in the presence of flow pulsation. We submit that ultrasonic velocity-change imaging under optical illumination may be an effective technique for diagnosing the presence of blood vessel plaques.

  12. Contrasting Actions of Selective Inhibitors of Angiopoietin-1 and Angiopoietin-2 on the Normalization of Tumor Blood Vessels

    PubMed Central

    Falcón, Beverly L.; Hashizume, Hiroya; Koumoutsakos, Petros; Chou, Jeyling; Bready, James V.; Coxon, Angela; Oliner, Jonathan D.; McDonald, Donald M.

    2009-01-01

    Angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) have complex actions in angiogenesis and vascular remodeling due to their effects on Tie2 receptor signaling. Ang2 blocks Ang1-mediated activation of Tie2 in endothelial cells under certain conditions but is a Tie2 receptor agonist in others. We examined the effects of selective inhibitors of Ang1 (mL4-3) or Ang2 (L1-7[N]), alone or in combination, on the vasculature of human Colo205 tumors in mice. The Ang2 inhibitor decreased the overall abundance of tumor blood vessels by reducing tumor growth and keeping vascular density constant. After inhibition of Ang2, tumor vessels had many features of normal blood vessels (normalization), as evidenced by junctional accumulation of vascular endothelial-cadherin, junctional adhesion molecule-A, and platelet/endothelial cell adhesion molecule-1 in endothelial cells, increased pericyte coverage, reduced endothelial sprouting, and remodeling into smaller, more uniform vessels. The Ang1 inhibitor by itself had little noticeable effect on the tumor vasculature. However, when administered with the Ang2 inhibitor, the Ang1 inhibitor prevented tumor vessel normalization, but not the reduction in tumor vascularity produced by the Ang2 inhibitor. These findings are consistent with a model whereby inhibition of Ang2 leads to normalization of tumor blood vessels by permitting the unopposed action of Ang1, but decreases tumor vascularity primarily by blocking Ang2 actions. PMID:19815705

  13. Large blood vessel stretch in lumbar spine through anterior surgical approach: An experimental study in adult goat

    PubMed Central

    Liu, Liehua; Wang, Haoming; Zhou, Qiang; Guo, Deyu; Lan, Yangjun; Liu, Ling

    2014-01-01

    Background: Various anterior lumbar surgical approaches, including the minimally invasive approach, have greatly improved in recent years. Vascular complications resulting from ALIF are frequently reported. Little information is available about the safety of large blood vessel stretch. We evaluated the right side stretch limit (RSSL) of the abdominal aorta (AAA) and the inferior vena cava (IVC) without blood flow occlusion and investigated stretch-induced histological injury and thrombosis in the iliac and femoral arteries and veins and the stretched vessels. Materials and Methods: The RSSL of blood vessels in five adult goats was measured by counting the number of 0.5-cm-thick wood slabs that were inserted between the right lumbar edge and the stretch hook. Twenty seven adult goats were divided into three groups to investigate histological injury and thrombosis under a stretch to 0.5 cm (group I) 1.5 cm (group II) for 2 h, or no stretch (group III). Blood vessel samples from groups I and II were analyzed on postsurgical days 1, 3, and 7. Thrombogenesis was examined in the iliac and femoral arteries and veins. Results: The RSSL of large blood vessels in front of L4/5 was 1.5 cm from the right lumbar edge. All goats survived surgery without complications. No injury or thrombosis in the large blood vessels in front of the lumbar vertebrae and in the iliac or femoral arteries and veins was observed. Under light microscopy, group I showed slight swelling of endothelial cells in the AAA and no histological injury of the IVC. The AAA of group II showed endothelial cell damage, unclear organelles, and incomplete cell connections by electron microscopy. Conclusions: The AAA and IVC in a goat model can be stretched by ?0.5 cm, with no thrombosis in the AAA, IVC, iliac or femoral arteries and veins. PMID:24741140

  14. Inosculation of blood vessels allows early perfusion and vitality of bladder grafts-implications for bioengineered bladder wall.

    PubMed

    Osborn, Stephanie L; So, Michelle; Hambro, Shannon; Nolta, Jan A; Kurzrock, Eric A

    2015-06-01

    Bioengineered bladder tissue is needed for patients with neurogenic bladder disease as well as for cancer. Current technologies in bladder tissue engineering have been hampered by an inability to efficiently initiate blood supply to the graft, ultimately leading to complications that include graft contraction, ischemia, and perforation. To date, the biological mechanisms of vascularization on transplant have not been suitably investigated for urologic tissues. To better understand the mechanisms of neovascularization on bladder wall transplant, a chimeric mouse model was generated such that angiogenesis and vasculogenesis could be independently assessed in vivo. Green fluorescence protein (GFP) transgenic mice received bone marrow transplants from ?-galactosidase (LacZ) transgenic animals and then subsequent bladder wall transplants from wild-type donor mice. Before euthanization, the aorta was infused with fluorescent microbeads (fluorospheres) to identify perfused vessels. The contributions of GFP (angiogenesis) and LacZ (vasculogenesis) to the formation of CD31-expressing blood vessels within the wild-type graft were evaluated by immunohistochemistry at different time points and locations within the graft (proximal, middle, and distal) to provide a spatiotemporal analysis of neovascularization. The GFP index, a measure of angiogenic host ingrowth, was significantly higher at proximal versus mid or distal regions in animals 2-16 weeks post-transplant. However, GFP index did not increase over time in any area. Within 7 days post-transplant, perfusion of primarily wild-type, donor blood vessels in the most distal areas of the graft was observed by intraluminal fluorospheres. In addition, chimeric host-donor (GFP-wild type) blood vessels were evident in proximal areas. The contribution of vasculogenesis to vascularization of the graft was limited, as LacZ cells were not specifically associated with the endothelial cells of blood vessels, but rather found primarily in areas of inflammation. The data suggest that angiogenesis of host blood vessels into the proximal region leads to inosculation between host and donor vessels and subsequent perfusion of the graft via pre-existing graft vessels within the first week after transplant. As such, the engineering of graft blood vessels and the promotion of inosculation might prevent graft contraction, thereby potentiating the use of bioengineered bladder tissue for transplantation. PMID:25794892

  15. Blood-brain barrier dysfunction and cerebral small vessel disease (arteriolosclerosis) in brains of older people.

    PubMed

    Bridges, Leslie R; Andoh, Joycelyn; Lawrence, Andrew J; Khoong, Cheryl H L; Poon, Wayne W; Esiri, Margaret M; Markus, Hugh S; Hainsworth, Atticus H

    2014-11-01

    The blood-brain barrier protects brain tissue from potentially harmful plasma components. Small vessel disease (SVD; also termed arteriolosclerosis) is common in the brains of older people and is associated with lacunar infarcts, leukoaraiosis, and vascular dementia. To determine whether plasma extravasation is associated with SVD, we immunolabeled the plasma proteins fibrinogen and immunoglobulin G, which are assumed to reflect blood-brain barrier dysfunction, in deep gray matter (DGM; anterior caudate-putamen) and deep subcortical white matter (DWM) in the brains of a well-characterized cohort of donated brains with minimal Alzheimer disease pathology (Braak Stages 0-II) (n = 84; aged 65 years or older). Morphometric measures of fibrinogen labeling were compared between people with neuropathologically defined SVD and aged control subjects. Parenchymal cellular labeling with fibrinogen and immunoglobulin G was detectable in DGM and DWM in many subjects (>70%). Quantitative measures of fibrinogen were not associated with SVD in DGM or DWM; SVD severity was correlated between DGM and DWM (p < 0.0001). Fibrinogen in DGM showed a modest association with a history of hypertension; DWM fibrinogen was associated with dementia and cerebral amyloid angiopathy (all p < 0.05). In DWM, SVD was associated with leukoaraiosis identified in life (p < 0.05), but fibrinogen was not. Our data suggest that, in aged brains, plasma extravasation and hence local blood-brain barrier dysfunction are common but do not support an association with SVD. PMID:25289893

  16. Effects of VA-045, a novel apovincaminic acid derivative, on isolated blood vessels: cerebroarterial selectivity.

    PubMed

    Miyata, N; Yamaura, H; Tanaka, M; Muramatsu, M; Tsuchida, K; Okuyama, S; Otomo, S

    1993-01-01

    We investigated the effects of VA-045, an apovincaminic acid derivative, on isolated blood vessels. VA-045 (10(-7)-10(-5) M) and vinpocetine (10(-7)-10(-5) M) inhibited the 64 mM KCl-induced and 10(-6)M norepinephrine (NE)-induced contraction of rat aortic strips. VA-045 (10(-7)-10(-4) M) and vinpocetine (10(-7)-10(-4) M) inhibited the activity of cyclic AMP and cyclic GMP phosphodiesterase in porcine coronary artery. VA-045 (3 x 10(-9-3 x 10(-6) M) relaxed the 64 mM KCl-induced contraction of the canine basilar artery without affecting the peripheral arteries. These results indicate that VA-045 selectively dilates canine cerebral artery, and that it may be a useful agent for the treatment of cerebrovascular diseases such as stroke. PMID:8387130

  17. Retina identification based on the pattern of blood vessels using fuzzy logic

    NASA Astrophysics Data System (ADS)

    Barkhoda, Wafa; Akhlaqian, Fardin; Amiri, Mehran Deljavan; Nouroozzadeh, Mohammad Sadeq

    2011-12-01

    This article proposed a novel human identification method based on retinal images. The proposed system composed of two main parts, feature extraction component and decision-making component. In feature extraction component, first blood vessels extracted and then they have been thinned by a morphological algorithm. Then, two feature vectors are constructed for each image, by utilizing angular and radial partitioning. In previous studies, Manhattan distance has been used as similarity measure between images. In this article, a fuzzy system with Manhattan distances of two feature vectors as input and similarity measure as output has been added to decision-making component. Simulations show that this system is about 99.75% accurate which make it superior to a great extent versus previous studies. In addition to high accuracy rate, rotation invariance and low computational overhead are other advantages of the proposed systems that make it ideal for real-time systems.

  18. Streaming flow from ultrasound contrast agents by acoustic waves in a blood vessel model.

    PubMed

    Cho, Eunjin; Chung, Sang Kug; Rhee, Kyehan

    2015-09-01

    To elucidate the effects of streaming flow on ultrasound contrast agent (UCA)-assisted drug delivery, streaming velocity fields from sonicated UCA microbubbles were measured using particle image velocimetry (PIV) in a blood vessel model. At the beginning of ultrasound sonication, the UCA bubbles formed clusters and translated in the direction of the ultrasound field. Bubble cluster formation and translation were faster with 2.25MHz sonication, a frequency close to the resonance frequency of the UCA. Translation of bubble clusters induced streaming jet flow that impinged on the vessel wall, forming symmetric vortices. The maximum streaming velocity was about 60mm/s at 2.25MHz and decreased to 15mm/s at 1.0MHz for the same acoustic pressure amplitude. The effect of the ultrasound frequency on wall shear stress was more noticeable. Maximum wall shear stress decreased from 0.84 to 0.1Pa as the ultrasound frequency decreased from 2.25 to 1.0MHz. The maximum spatial gradient of the wall shear stress also decreased from 1.0 to 0.1Pa/mm. This study showed that streaming flow was induced by bubble cluster formation and translation and was stronger upon sonication by an acoustic wave with a frequency near the UCA resonance frequency. Therefore, the secondary radiant force, which is much stronger at the resonance frequency, should play an important role in UCA-assisted drug delivery. PMID:26025507

  19. Distinct cellular mechanisms of blood vessel fusion in the zebrafish embryo.

    PubMed

    Herwig, Lukas; Blum, Yannick; Krudewig, Alice; Ellertsdottir, Elin; Lenard, Anna; Belting, Heinz-Georg; Affolter, Markus

    2011-11-22

    Although many of the cellular and molecular mechanisms of angiogenesis have been intensely studied [1], little is known about the processes that underlie vascular anastomosis. We have generated transgenic fish lines expressing an EGFP-tagged version of the junctional protein zona occludens 1 (ZO1) to visualize individual cell behaviors that occur during vessel fusion and lumen formation in vivo. These life observations show that endothelial cells (ECs) use two distinct morphogenetic mechanisms, cell membrane invagination and cord hollowing to generate different types of vascular tubes. During initial steps of anastomosis, cell junctions that have formed at the initial site of cell contacts expand into rings, generating a cellular interface of apical membrane compartments, as defined by the localization of the apical marker podocalyxin-2 (Pdxl2). During the cord hollowing process, these apical membrane compartments are brought together via cell rearrangements and extensive junctional remodeling, resulting in lumen coalescence and formation of a multicellular tube. Vessel fusion by membrane invagination occurs adjacent to a preexisting lumen in a proximal to distal direction and is blood-flow dependent. Here, the invaginating inner cell membrane undergoes concomitant apicobasal polarization and the vascular lumen is formed by the extension of a transcellular lumen through the EC, which forms a unicellular or seamless tube. PMID:22079115

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

    PubMed

    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

    2013-11-01

    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

  1. Heterogeneous histochemical reaction pattern of the lectin Bandeiraea (Griffonia) simplicifolia with blood vessels of human full-term placenta

    Microsoft Academic Search

    Ingrid Lang; Tom Hahn; Gottfried Dohr; Gerhard Skofitsch; Gernot Desoye

    1994-01-01

    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

  2. Alzheimer's disease and CADASIL are heritable, adult-onset dementias that both involve damaged small blood vessels.

    PubMed

    Marchesi, Vincent T

    2014-03-01

    This essay explores an alternative pathway to Alzheimer's dementia that focuses on damage to small blood vessels rather than late-stage toxic amyloid deposits as the primary pathogenic mechanism that leads to irreversible dementia. While the end-stage pathology of AD is well known, the pathogenic processes that lead to disease are often assumed to be due to toxic amyloid peptides that act on neurons, leading to neuronal dysfunction and eventually neuronal cell death. Speculations as to what initiates the pathogenic cascade have included toxic abeta peptide aggregates, oxidative damage, and inflammation, but none explain why neurons die. Recent high-resolution NMR studies of living patients show that lesions in white matter regions of the brain precede the appearance of amyloid deposits and are correlated with damaged small blood vessels. To appreciate the pathogenic potential of damaged small blood vessels in the brain, it is useful to consider the clinical course and the pathogenesis of CADASIL, a heritable arteriopathy that leads to damaged small blood vessels and irreversible dementia. CADASIL is strikingly similar to early onset AD in that it is caused by germ line mutations in NOTCH 3 that generate toxic protein aggregates similar to those attributed to mutant forms of the amyloid precursor protein and presenilin genes. Since NOTCH 3 mutants clearly damage small blood vessels of white matter regions of the brain that lead to dementia, we speculate that both forms of dementia may have a similar pathogenesis, which is to cause ischemic damage by blocking blood flow or by impeding the removal of toxic protein aggregates by retrograde vascular clearance mechanisms. PMID:24378989

  3. Three-dimensional multi-scale model of deformable platelets adhesion to vessel wall in blood flow.

    PubMed

    Wu, Ziheng; Xu, Zhiliang; Kim, Oleg; Alber, Mark

    2014-08-01

    When a blood vessel ruptures or gets inflamed, the human body responds by rapidly forming a clot to restrict the loss of blood. Platelets aggregation at the injury site of the blood vessel occurring via platelet-platelet adhesion, tethering and rolling on the injured endothelium is a critical initial step in blood clot formation. A novel three-dimensional multi-scale model is introduced and used in this paper to simulate receptor-mediated adhesion of deformable platelets at the site of vascular injury under different shear rates of blood flow. The novelty of the model is based on a new approach of coupling submodels at three biological scales crucial for the early clot formation: novel hybrid cell membrane submodel to represent physiological elastic properties of a platelet, stochastic receptor-ligand binding submodel to describe cell adhesion kinetics and lattice Boltzmann submodel for simulating blood flow. The model implementation on the GPU cluster significantly improved simulation performance. Predictive model simulations revealed that platelet deformation, interactions between platelets in the vicinity of the vessel wall as well as the number of functional GPIb? platelet receptors played significant roles in platelet adhesion to the injury site. Variation of the number of functional GPIb? platelet receptors as well as changes of platelet stiffness can represent effects of specific drugs reducing or enhancing platelet activity. Therefore, predictive simulations can improve the search for new drug targets and help to make treatment of thrombosis patient-specific. PMID:24982253

  4. A Blood-Resistant Surgical Glue for Minimally Invasive Repair of Vessels and Heart Defects

    PubMed Central

    Lang, Nora; Pereira, Maria J.; Lee, Yuhan; Friehs, Ingeborg; Vasilyev, Nikolay V.; Feins, Eric N.; Ablasser, Klemens; O'Cearbhaill, Eoin D.; Xu, Chenjie; Fabozzo, Assunta; Padera, Robert; Wasserman, Steve; Freudenthal, Franz; Ferreira, Lino S.; Langer, Robert

    2014-01-01

    Currently, there are no clinically approved surgical glues that are nontoxic, bind strongly to tissue, and work well within wet and highly dynamic environments within the body. This is especially relevant to minimally invasive surgery that is increasingly performed to reduce postoperative complications, recovery times, and patient discomfort. We describe the engineering of a bioinspired elastic and biocompatible hydrophobic light-activated adhesive (HLAA) that achieves a strong level of adhesion to wet tissue and is not compromised by preexposure to blood. The HLAA provided an on-demand hemostatic seal, within seconds of light application, when applied to high-pressure large blood vessels and cardiac wall defects in pigs. HLAA-coated patches attached to the interventricular septum in a beating porcine heart and resisted supraphysiologic pressures by remaining attached for 24 hours, which is relevant to intracardiac interventions in humans. The HLAA could be used for many cardiovascular and surgical applications, with immediate application in repair of vascular defects and surgical hemostasis. PMID:24401941

  5. Characterization of imidazoline receptors in blood vessels for the development of antihypertensive agents.

    PubMed

    Chen, Mei-Fen; Tsai, Jo-Ting; Chen, Li-Jen; Wu, Tung-Pi; Yang, Jia-Jang; Yin, Li-Te; Yang, Yu-Lin; Chiang, Tai-An; Lu, Han-Lin; Wu, Ming-Chang

    2014-01-01

    It has been indicated that activation of peripheral imidazoline I2-receptor (I-2R) may reduce the blood pressure in spontaneously hypertensive rats (SHRs). Also, guanidinium derivatives show the ability to activate imidazoline receptors. Thus, it is of special interest to characterize the I-2R using guanidinium derivatives in blood vessels for development of antihypertensive agent(s). Six guanidinium derivatives including agmatine, amiloride, aminoguanidine, allantoin, canavanine, and metformin were applied in this study. Western blot analysis was used for detecting the expression of imidazoline receptor in tissues of Wistar rats. The isometric tension of aortic rings isolated from male rats was also estimated. The expression of imidazoline receptor on rat aorta was identified. However, guanidinium derivatives for detection of aortic relaxation were not observed except agmatine and amiloride which induced a marked relaxation in isolated aortic rings precontracted with phenylephrine or KCl. Both relaxations induced by agmatine and amiloride were attenuated by glibenclamide at concentration enough to block ATP-sensitive potassium (KATP) channels. Meanwhile, only agmatine-induced relaxation was abolished by BU224, a selective antagonist of imidazoline I2-receptors. Taken together, we suggest that agmatine can induce vascular relaxation through activation of peripheral imidazoline I2-receptor to open KATP channels. Thus, agmatine-like compound has the potential to develop as a new therapeutic agent for hypertension in the future. PMID:24800210

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

    PubMed

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

    2010-05-01

    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

  7. Fibroblast growth factor signaling affects vascular outgrowth and is required for the maintenance of blood vessel integrity.

    PubMed

    De Smet, Frederik; Tembuyser, Bieke; Lenard, Anna; Claes, Filip; Zhang, Jie; Michielsen, Christof; Van Schepdael, Ann; Herbert, Jean-Marc; Bono, Françoise; Affolter, Markus; Dewerchin, Mieke; Carmeliet, Peter

    2014-10-23

    Angiogenesis contributes to the development of numerous disorders. Even though fibroblast growth factors (FGFs) were discovered as mediators of angiogenesis more than 30 years ago, their role in developmental angiogenesis still remains elusive. We use a recently described chemical probe, SSR128129E (SSR), that selectively inhibits the action of multiple FGF receptors (FGFRs), in combination with the zebrafish model to examine the role of FGF signaling in vascular development. We observe that while FGFR signaling is less important for vessel guidance, it affects vascular outgrowth and is especially required for the maintenance of blood vessel integrity by ensuring proper cell-cell junctions between endothelial cells. In conclusion, our work illustrates the power of a small molecule probe to reveal insights into blood vessel formation and stabilization and thus of broad interest to the vascular biology community. PMID:25200605

  8. The pia mater at the site of the entry of blood vessels into the central nervous system

    Microsoft Academic Search

    V. Krahn

    1982-01-01

    The entry of blood vessels into the central nervous system (CNS) has been studied at the surface of the brain stem and the spinal cord of two cats and two rabbits. The study was carried out by scanning electron microscopy (SEM). The results obtained by SEM concerning the layers of the pia mater corresponded to those obtained by other authors

  9. Scanning electron microscopic study on the development of primitive blood vessels in chick embryos at the early somite-stage

    Microsoft Academic Search

    Reiji Hirakow; Tamiko Hiruma

    1981-01-01

    Primary vasculogenesis in chick embryos at the early somite stage 11–14 somites) was investigated mainly by scanning electron microscopy (SEM), with special reference to the development of primitive blood vessels such as the arteria et vena vitellina (AV, VV), aorta dorsalis (AD) and vena cardinalis (VC). After glutaraldehyde fixation, the endoderm or ectoderm was removed from the embryos to expose

  10. Analysis of cooling effect by blood vessel on temperature rise due to ultrasound radiation in tissue phantom

    NASA Astrophysics Data System (ADS)

    Shimizu, Kazuma; Tsuchiya, Takenobu; Fukasawa, Kota; Hatano, Yuichi; Endoh, Nobuyuki

    2015-07-01

    Ultrasound diagnostic equipment using ultrasound pulse–echo techniques is considered minimally invasive and highly versatile. However, one of the causes of damage due to ultrasound radiation is temperature rise caused by the absorption of sound energy. Therefore, it is very important to estimate the temperature rise caused by the radiation of ultrasound. Sound intensity in a medium is analyzed by the finite-difference time-domain (FDTD) method, and the temperature distribution caused by sound is estimated by the heat conduction equation (HCE) method in this study. Because blood vessels keep the temperature constant in tissues, the cooling effect of blood flow has to be taken into account for the precise estimation of temperature rise in human tissues. In general, it is well known that capillary vessels are mainly responsible for the cooling effect in tissues and their effect can be estimated as a function of bloodstream ratio. In this paper, a preliminary study on the cooling effect by a large vessel is described for the precise estimation of temperature rise. Blood flow in blood vessels is analyzed using the Navier–Stokes equation. To confirm the precision of the numerical analysis, the results of the numerical analysis are compared with the experimental results using a soft tissue phantom.

  11. IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 8, NO. 3, SEPTEMBER 1989 263 Detection of Blood Vessels in Retinal Images Using

    E-print Network

    Hoover, Adam

    in extracting various features in an image. In this paper, we address the problem of detecting blood vessels extraction based on the optical and spatial properties of objects to be recognized. The gray-level profile-scale morphology has been suggested in 131. It involves simple erosion and dilation operators and can

  12. Cell-Demanded Liberation of VEGF121 From Fibrin Implants Induces Local and Controlled Blood Vessel Growth

    Microsoft Academic Search

    Martin Ehrbar; Valentin G. Djonov; Christian Schnell; Stefan A. Tschanz; Georg Martiny-Baron; Ursula Schenk; Jeanette Wood; Peter H. Burri; Jeffrey A. Hubbell; Andreas H. Zisch

    2008-01-01

    Although vascular endothelial growth factor (VEGF) has been described as a potent angiogenic stimulus, its application in therapy remains difficult: blood vessels formed by exposure to VEGF tend to be malformed and leaky. In nature, the principal form of VEGF possesses a binding site for ECM components that maintain it in the immobilized state until released by local cellular enzymatic

  13. Optimal trajectory for a microrobot navigating in blood vessels Laurent Arcese, Ali Cherry, Matthieu Fruchard, Antoine Ferreira

    E-print Network

    Paris-Sud XI, Université de

    Optimal trajectory for a microrobot navigating in blood vessels Laurent Arcese, Ali Cherry. Cherry and A. Ferreira are with the Institut PRISME UPRES 4229, ENSI de Bourges, 88 Bd Lahitolle, 18000, Bourges, France ali.cherry@ensi-bourges.fr antoine.ferreira@ensi-bourges.fr steer nanoscale robots

  14. Msx genes define a population of mural cell precursors required for head blood vessel Miguel Lopes1

    E-print Network

    Boyer, Edmond

    1 Msx genes define a population of mural cell precursors required for head blood vessel maturation cedex Keywords Msx, BMP, neural crest pasteur-00611700,version1-27Jul2011 Author manuscript, published that, in the mouse embryo, Msx1Lacz and Msx2Lacz genes are expressed in mural and in a few endothelial

  15. Clinical evaluation of scanning laser polarimetry: I Intraoperator reproducibility and design of a blood vessel removal algorithm

    PubMed Central

    Waldock, A.; Potts, M.; Sparrow, J.; Karwatowski, W.

    1998-01-01

    AIMS—To evaluate the reproducibility of the retardation values (change in polarisation) obtained with the scanning laser polarimeter in a series of normal subjects and glaucoma patients. To improve the analysis of the raw data by devising and evaluating a blood vessel removal algorithm.?METHODS—Scanning laser polarimetry was performed on 10 normal subjects and 10 glaucoma patients. A series of six images was obtained from each eye. The normal subjects were re-imaged 3 months after their initial assessment. The retardation values obtained from each eye were analysed using the authors' own methods, including the use of an algorithm to remove blood vessels from the polar profiles. The reproducibility of these measurements and the performance of the blood vessel removal algorithm were assessed.?RESULTS—The "individual point" coefficient of variation was approximately 12.5% for normal subjects and 17.0% for glaucoma patients. The "integral" coefficient of variation for these groups was approximately 5.5% and 9.5% respectively. The reproducibility of the measurements did not improve with an increased number of measurements. There was no difference in the reproducibility of the measurements in normal subjects over time. The blood vessel removal algorithm improved the reproducibility of the measurements when the shape of the profile was assessed.?CONCLUSION—The intraoperator reproducibility of retardation values obtained with the scanning laser polarimeter is satisfactory for its use as a clinical tool. The use of a blood vessel removal algorithm improves the reproducibility of the measurements and also assists the clinician in the interpretation of the polar profiles. Furthermore, it allows the construction of normal database polar profiles, thereby enabling the identification, location and quantification of retinal nerve fibre layer damage in an "at risk" individual's polar profile.?? Keywords: scanning laser polarimetry; glaucoma; reproducibility; algorithm PMID:9602621

  16. [Aetiology and pathogenesis of damages to blood vessels in drug addicts].

    PubMed

    Sultanaliev, T A; Tursynbaev, S E; Ivakin, V M

    2007-01-01

    The article deals with the problems concerning aetiology and pathogenesis of damages to blood vessels in patients practicing parenteral administration of surrogates of narcotic substances. In order to clinically and experimentally study the pattern of morphological alterations in the area of narcotic substances administration and to work out an appropriate classification of the forms and stages of development of the pathological process, the authors analysed the clinical course of vascular lesions and complications thereof in a total of 244 drug abusers having parenterally administered surrogates of narcotic substances and undergoing treatment at the Department of Vascular Surgery of the Municipal Clinical Hospital of the city of Almaty. Additionally, experimental studies were carried out on 16 rabbits with the induced model of parenteral administration of surrogates of narcotic substances, thus making it possible to study the degree of their effect and to confirm the theory of a chemical impact of the homemade drugs on the vascular wall. The findings of the carried out studies enabled us to single out the following clinical stages of vascular lesions: stage I - the initial stage of cicatricial-and-ulcerous lesions formation, stage II - formation of cutaneous-and-vascular fistulas, stage III - the stage of complications characterized by development of health-hazardous vascular lesions, i. e., arterial and venous thromboses of the major vessels, as well as arrosive bleedings. It was noted that more than 50% of patients were admitted to the clinic presenting with the third stage of vascular lesions. The experimental part of the study included 64 experiments on 16 rabbits (one experiment per each paw of the animal). The laboratory animals were subdivided into three groups. The first experimental group consisted of the rabbits with a mechanically inflicted injury to the vessels. The second and third experimental groups were composed of the rabbits having received injections simulating various surrogates of narcotic substances. It was experimentally confirmed that the dominating factor was a chemical injury - a locally irritating effect on the vascular wall and paravasal tissues, while the process of the damaged area infection turned out to be secondary, thus belonging to a complication of the chemical injury concerned. PMID:18004256

  17. Investigation of source-detector separation optimization for an implantable perfusion and oxygenation sensor for liver blood vessels

    SciTech Connect

    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

    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.

  18. Thermal Expansion of Vitrified Blood Vessels Permeated with DP6 and Synthetic Ice Modulators

    PubMed Central

    Eisenberg, David P.; Taylor, Michael J.; Jimenez-Rios, Jorge L.; Rabin, Yoed

    2014-01-01

    This study provides thermal expansion data for blood vessels permeated with the cryoprotective cocktail DP6, when combined with selected synthetic ice modulators (SIMs): 12% polyethylene glycol 400, 6% 1,3-cyclohexanediol, and 6% 2,3-butanediol. The general classification of SIMs includes molecules that modulate ice nucleation and growth, or possess properties of stabilizing the amorphous state, by virtue of their chemical structure and at concentrations that are not explained on a purely colligative basis. The current study is part of an ongoing effort to characterize thermo-mechanical effects on structural integrity of cryopreserved materials, where thermal expansion is the driving mechanism to thermo-mechanical stress. This study focuses on the lower part of the cryogenic temperature range, where the cryoprotective agent (CPA) behaves as a solid for all practical applications. By combining results obtained in the current study with literature data on the thermal expansion in the upper part of the cryogenic temperature range, unified thermal expansion curves are presented. PMID:24769313

  19. Electrospun tecophilic/gelatin nanofibers with potential for small diameter blood vessel tissue engineering.

    PubMed

    Vatankhah, Elham; Prabhakaran, Molamma P; Semnani, Dariush; Razavi, Shahnaz; Morshed, Mohammad; Ramakrishna, Seeram

    2014-12-01

    Tissue engineering techniques particularly using electrospun scaffolds have been intensively used in recent years for the development of small diameter vascular grafts. However, the development of a completely successful scaffold that fulfills multiple requirements to guarantee complete vascular regeneration remains challenging. In this study, a hydrophilic and compliant polyurethane namely Tecophilic (TP) blended with gelatin (gel) at a weight ratio of 70:30 (TP(70)/gel(30)) was electrospun to fabricate a tubular composite scaffold with biomechanical properties closely simulating those of native blood vessels. Hydrophilic properties of the composite scaffold induced non-thrombogenicity while the incorporation of gelatin molecules within the scaffold greatly improved the capacity of the scaffold to serve as an adhesive substrate for vascular smooth muscle cells (SMCs), in comparison to pure TP. Preservation of the contractile phenotype of SMCs seeded on electrospun TP(70)/gel(30) was yet another promising feature of this scaffold. The nanostructured TP(70)/gel(30) demonstrated potential feasibility toward functioning as a vascular graft. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1165-1180, 2014. PMID:25042000

  20. A New Device for Mechanical Testing of Blood Vessels at Cryogenic Temperatures.

    PubMed

    Jimenez Rios, Jorge L; Rabin, Yoed

    2007-01-01

    As part of an ongoing program to study the thermo-mechanical effects associated with cryopreservation via vitrification (vitreous in Latin means glassy), the current study focuses on the development of a new device for mechanical testing of blood vessels at cryogenic temperatures. This device is demonstrated on a bovine carotid artery model, permeated with the cryoprotectant cocktail VS55 and a reference solution of 7.05M DMSO, below glass transition. Results are also presented for crystallized specimens, in the absence of cryoprotectants. Results indicate that the elastic modulus of a specimen with no cryoprotectant, at about -140°C (8.6°C and 15.5°C below the glass transition temperature of 7.05M DMSO and VS55, respectively), is 1038.8 ± 25.2 MPa, which is 8% and 3% higher than that of a vitrified specimen permeated with 7.05M DMSO and VS55, respectively. The elastic modulus of a crystallized material at -50°C is lower by ~20% lower from that at -140°C. PMID:18958183

  1. Proteomic View of Basement Membranes from Human Retinal Blood Vessels, Inner Limiting Membranes, and Lens Capsules.

    PubMed

    Uechi, Guy; Sun, Zhiyuan; Schreiber, Emanuel M; Halfter, Willi; Balasubramani, Manimalha

    2014-07-17

    Basement membranes (BMs) are extracellular matrix sheets comprising the laminins, type-IV collagens, nidogens, and the heparan sulfate proteoglycans, perlecan, collagen XVIII, and agrin. In intact BMs, BM proteins are physiologically insoluble and partially resistant to proteolytic digestion, making BMs a challenge to study. Here three types of BMs from adult human eyes, the inner limiting membrane (ILM), the retinal vascular BMs, and the lens capsule, were isolated for analysis by 1D-SDS-PAGE and LC-MS/MS. Peptide and protein identifications were done using MaxQuant. 1129 proteins were identified with a 1% false discovery rate. Data showed that BMs are composed of multiple laminins, collagen IVs, nidogens, and proteoglycans. The dominant laminin family member in all BMs was laminin ?5?2?1. The dominant collagen IV trimer in lens capsule (LC) and blood vessel (BV) BMs had a chain composition of ?1(IV)2, ?2 (IV), whereas the dominant collagen IV in the ILM had the ?3(IV), ?4(IV), ?5(IV) chain composition. The data also showed that the ratio of laminin and collagen IVs varied among different BM types: the ratio of collagen IV to the other BM proteins is highest in LC, followed by BV and lowest for the ILM. The data have been deposited to the ProteomeXchange with identifier PXD001025. PMID:24990792

  2. Modeling of the Human Aortic Arch with Its Major Branches for Computational Fluid Dynamics Simulation of the Blood Flow

    Microsoft Academic Search

    Daisuke Mori; Tomoaki Hayasaka; Takami Yamaguchi

    2002-01-01

    We devised a method that combines the differential geometrical technique and overset grid formation to construct an aortic arch model for computational fluid dynamics (CFD) simulations. The simulations incorporate both non-planarity and the major branches at the top of the arch, using a set of magnetic resonance (MR) images, and we discuss their combined effects on blood flow. The results

  3. Dual beam Doppler FD-OCT system with integrated Dynamic Vessel Analyzer and rotatable beams to measure total retinal blood flow

    NASA Astrophysics Data System (ADS)

    Doblhoff-Dier, Veronika; Werkmeister, René M.; Gröschl, Martin; Schmetterer, Leopold

    2014-03-01

    We present a method capable of measuring the total retinal blood flow in arteries and veins based on dual beam Fourierdomain Doppler optical coherence tomography (OCT) in combination with a fundus camera based Dynamic Vessel Analyzer. Incorporating a Dynamic vessel analyzer into the system not only gives a live image of the fundus - it also allows determining the vessels' diameter precisely during the OCT measurement, which is necessary for the determination of the blood flow. While dual beam systems with fixed detection plane allow only vessels with certain orientations to be measured, the detection plane of our system can be rotated by 90°. This ensures that the blood's velocity can be measured in all vessels around the optic nerve head. The results of the total blood flow measurements are in the same range as previously published data. Additionally, the high degree of conformity between the measured venous and arterial flow corroborated the system's validity. For larger vessels, the logarithmic values of vessel diameter and blood flow were found to be related linearly with a regression coefficient of around 3, which is in accordance with Murray's law. For smaller vessels (diameter below 60 ?m), the values diverge from the linear dependence. The high sensitivity and the good agreement with published data suggest a high potential for examining the retinal blood flow in patients with ocular diseases.

  4. Prominent expression of sialyl Lewis X-capped core 2-branched O-glycans on high endothelial venule-like vessels in gastric MALT lymphoma

    PubMed Central

    Kobayashi, Motohiro; Mitoma, Junya; Hoshino, Hitomi; Yu, Shin-Yi; Shimojo, Yasuyo; Suzawa, Kenichi; Khoo, Kay-Hooi; Fukuda, Minoru; Nakayama, Jun

    2011-01-01

    High endothelial venule (HEV)-like vessels have been observed in gastric B-cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma), as well as in its preceding lesion, chronic Helicobacter pylori gastritis. Previously we reported that glycans on HEV-like vessels in the latter lesion served as L-selectin ligands. However, the biochemical and functional nature of glycans on HEV-like vessels in gastric MALT lymphoma remained to be determined. In this study, we performed immunohistochemical analysis for sialyl Lewis X (sLeX)-related glycoepitopes using three monoclonal antibodies MECA-79, HECA-452, and NCC-ST-439, and found that MECA-79?/HECA-452+/NCC-ST-439+ HEV-like vessels preferentially appears in gastric MALT lymphoma compared to chronic H. pylori gastritis, suggesting that appearance of MECA-79?/HECA-452+/NCC-ST-439+ HEV-like vessels marks gastric MALT lymphoma. We then constructed a set of CHO cell lines expressing possible MECA-79?/HECA-452+/NCC-ST-439+ glycans, as well as other sLeX-type glycans, on CD34, and evaluated L-selectin binding to those cells using L-selectin•IgM chimera binding and lymphocyte adhesion assays. L-selectin•IgM chimeras bound to CHO cells expressing 6-sulfo sLeX attached to core 2-branched O-glycans with or without 6-sulfo sLeX attached to extended core 1 O-glycans but only marginally to other CHO cell lines. On the other hand, CHO cells expressing 6-sulfo sLeX attached to extended core 1 and/or core 2-branched O-glycans, and also non-sulfated sLeX attached to core 2-branched O-glycans showed substantial lymphocyte binding, while binding was negligible on cell lines expressing 6-sulfo and non-sulfated sLeX attached to N-glycans and non-sulfated sLeX attached to extended core 1 O-glycans. These results indicate that MECA-79?/HECA-452+/NCC-ST-439+ glycans, namely 6-sulfo and non-sulfated sLeXs attached to core 2-branched O-glycans, expressed on HEV-like vessels in gastric MALT lymphoma, function as L-selectin ligands and likely contribute to H. pylori-specific T-cell recruitment in the progression of gastric MALT lymphoma. PMID:21432854

  5. Locating blood vessels in retinal images by piece-wise threshold probing of a matched filter response.

    PubMed Central

    Hoover, A.; Kouznetsova, V.; Goldbaum, M.

    1998-01-01

    We describe an automated method to locate and outline blood vessels in images of the ocular fundus. Such a tool should prove useful to eyecare 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. A comparison of our method against hand-labeled ground truth segmentations of five images yielded 65% sensitivity and 81% specificity. A previously known technique yielded 69% sensitivity and 63% specificity. For a baseline, we also compared the ground truth against a second hand labeling, yielding 80% sensitivity and 90% specificity. These numbers indicate our method improves upon the previously known technique, but that further improvement is still possible. Images Figure 1 PMID:9929355

  6. Molecular dynamics simulation of soft grains: Malaria-infected red blood cells motion within obstructed 2-D capillary vessel

    NASA Astrophysics Data System (ADS)

    Haris, L.; Khotimah, S. N.; Haryanto, F.; Viridi, S.

    2014-02-01

    Molecular dynamics has been widely used to numerically solve equation of motion of classical many-particle system. It can be used to simulate many systems including biophysics, whose complexity level is determined by the involved elements. Based on this method, a numerical model had been constructed to mimic the behaviour of malaria-infected red blood cells within capillary vessel. The model was governed by three forces namely Coulomb force, normal force, and Stokes force. By utilizing two dimensional four-cells scheme, theoretical observation was carried out to test its capability. Although the parameters were chosen deliberately, all of the quantities were given arbitrary value. Despite this fact, the results were quite satisfactory. Combined with the previous results, it can be said that the proposed model were sufficient enough to mimic the malaria-infected red blood cells motion within obstructed capillary vessel.

  7. Blood flow reduction of covered small side branches after flow diverter treatment: a computational fluid hemodynamic quantitative analysis.

    PubMed

    Hu, Peng; Qian, Yi; Zhang, Yu; Zhang, Hong-Qi; Li, Yang; Chong, Winston; Ling, Feng

    2015-04-13

    Small side branches related brain infarction remains one of the major concerns for flow-diverter devices. However, among several factors, whether this high-profile stent would significantly block blood flow into small side branches remains unclear. The authors quantitatively evaluate blood flow reduction due to the deployment of flow-diverter devices using computational fluid dynamics approach. Thirty one patient-specific anterior inferior cerebellar artery geometries were employed. The flow-diverter device was hypothetically embedded into the basilar trunk, and to cover the anterior inferior cerebellar arteries. The blood flow reduction of each anterior inferior cerebellar artery following flow-diverter device deployment was calculated, with independent validations for both inflow and outflow conditions. Efficient diameters of the anterior inferior cerebellar arteries were calculated to evaluate any correlation with blood flow reduction after flow-diverter devices. The blood flow reduction ratio was shown to be 3.61±1.94%. There was moreover no significant difference of either inflow or outflow boundary conditions during the simulation. The results were calculated approximately as a modest linear correlation between the blood flow reduction ratio and the size of anterior anterior inferior cerebellar arteries which had a mean efficient diameter of 1.12±0.36 mm (range from 0.31 mm to 1.91 mm), and the R(2) was 0.361. When covered by flow-diverter devices, the mechanical blood flow reduction in anterior inferior cerebellar arteries was found to be low with a maximum value estimated to be less than 8%. Therefore, mechanical blood flow reduction is probably not the leading factor contributing to small side branches related brain infarction. PMID:25748223

  8. Collateral blood flow between left coronary artery bypass grafts and chronically occluded right coronary circulation in patients with triple vessel disease. Observations during complete revascularisation of beating hearts

    Microsoft Academic Search

    Jean-Philippe Verhoye; Issam Abouliatim; Agnes Drochon; Bertand de Latour; Christophe Leclercq; Alain Leguerrier

    2010-01-01

    Objective: Preoperative measurements of collateral blood flow in patients with triple vessel disease and chronic occlusions of the right coronary artery do not, currently, ascertain the need to revascularise an occluded right coronary artery. We performed direct measurements of flow across left coronary bypass grafts to determine their contributions to collateral blood flow. Methods: Collateral blood flow was scored preoperatively

  9. Collateral blood flow between left coronary artery bypass grafts and chronically occluded right coronary circulation in patients with triple vessel disease. Observations during complete revascularisation of beating hearts

    Microsoft Academic Search

    Jean-Philippe Verhoye; Issam Abouliatim; Agnes Drochon; Bertand de Latour; Christophe Leclercq; Alain Leguerrier; Hervé Corbineau

    2007-01-01

    Objective: Preoperative measurements of collateral blood flow in patients with triple vessel disease and chronic occlusions of the right coronary artery do not, currently, ascertain the need to revascularise an occluded right coronary artery. We performed direct measurements of flow across left coronary bypass grafts to determine their contributions to collateral blood flow. Methods: Collateral blood flow was scored preoperatively

  10. Demonstration of three dimensional imaging of blood vessel using a no moving parts electronic lens-based optical confocal microscope

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.; Sheikh, Mumtaz; Webb-Wood, Grady; Kik, Pieter

    2007-03-01

    To the best of our knowledge, for the first time, biological Three Dimensional (3-D) imaging has been achieved using an electronically controlled optical lens to accomplish no-moving parts depth section scanning in a modified commercial 3-D confocal microscope. Specifically, full 3-D views of a standard CDC blood vessel (enclosed in a glass slide) have been obtained using the modified confocal microscope operating at the red 633 nm laser wavelength.

  11. Changes in the distribution of endothelial surface glycoconjugates associated with altered permeability of brain micro-blood vessels

    Microsoft Academic Search

    A. W. Vorbrodt

    1986-01-01

    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

  12. [The blood vessel supply of the testis in Pekin drakes (Anas platyrhynchos L.). Macroscopic, light microscopic and scanning electron microscopic studies].

    PubMed

    Kremer, A; Budras, K D

    1990-01-01

    Testes of Pekin ducks were macerated following injection with plastic at the period of maximal spermatogenesis which occurs during spring. The right and left A. testicularis arise from the A. renalis cranialis. The right testis is additionally supplied by an irregularly occurring A. testicularis accessoria. After penetrating the testicular capsule the arteries run to the centre of the testis and terminate as branching Aa. radiatae centrifugales. The seminiferous tubules are surrounded by intertubular and peritubular capillaries forming a rope-ladder-like system. Venules and veins run peripherally to enter the vein converge into the testicular hilus, and unite to form 2 Vv. testiculares which empty into the V. cava caudalis. Regulation of testicular blood supply is achieved by throttle devices depending on the avian seasonal cycle. The coiled and step-like course of the vessels results in a sufficient contact between blood and seminiferous tubules. Testicular veins surrounding the arteries might be an equivalent of the steroid transfer mechanism in the mammalian spermatic cord. PMID:2260767

  13. Increased Superoxide and Endothelial NO Synthase Uncoupling in Blood Vessels of Bmal1-Knockout Mice

    PubMed Central

    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

    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.) PMID:22912383

  14. Retinal Vessel Centerline Extraction Using Multiscale Matched Filter and Sparse Representation-Based Classifier

    Microsoft Academic Search

    Bob Zhang; Qin Li; Lei Zhang; Jane You; Fakhri Karray

    2010-01-01

    \\u000a Retina located in the back of the eye contains useful information in the diagnosis of certain diseases. By locating a blood\\u000a vessel’s width, color, reflectivity, tortuosity and abnormal branching, one can deduce the existence of these diseases. In\\u000a order for this to be achieved, blood vessels first need to be extracted from its background in fundus image. In this paper

  15. Cortical bone fluid flow and species transport induced by an array of blood vessels

    Microsoft Academic Search

    Russell G. Keanini

    1994-01-01

    A mathematical model is developed which describes cortical bone fluid flow and species transport in the vicinity of several in-bone vessel canals. Model simulations are qualitatively consistent with experimental observations and indicate that solute contact with the surrounding bone is approximately 85 percent complete when vessel canal radii are larger than ~1 percent of the cortex's thickness. In contrast, essentially

  16. Deep in vivo two-photon imaging of blood vessels with a new dye encapsulated in pluronic nanomicelles

    PubMed Central

    Maurin, Mathieu; Stéphan, Olivier; Vial, Jean-Claude; Marder, Seth R.; Van Der Sanden, Boudewijn

    2011-01-01

    The purpose of this work was to validate the use of Pluronic fluorescent nanomicelles 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 was compared to a classic blood pool dye Rhodamin B dextran (70 kDa) using two-photon microscopy. Pluronic nanomicelles showed, like Rhodamin B dextran, a homogeneous blood plasma staining for at least 1 hour after intravenous injection. Their two-photon imaging depth was 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 co-polymers is a valuable approach for encapsulating two-photon fluorescent dyes that are hydrophobic and not suitable for intravenous injection. PMID:21456865

  17. Deep in vivo two-photon imaging of blood vessels with a new dye encapsulated in pluronic nanomicelles

    NASA Astrophysics Data System (ADS)

    Maurin, Mathieu; Stéphan, Olivier; Vial, Jean-Claude; Marder, Seth R.; van der Sanden, Boudewijn

    2011-03-01

    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.

  18. Quantification of Wall Shear Stress in Large Blood Vessels Using Lagrangian Interpolation Functions with Cine Phase-Contrast Magnetic Resonance Imaging

    Microsoft Academic Search

    Christopher P. Cheng; David Parker; Charles A. Taylor

    2002-01-01

    Arterial wall shear stress is hypothesized to be an important factor in the localization of atherosclerosis. Current methods to compute wall shear stress from magnetic resonance imaging (MRI) data do not account for flow profiles characteristic of pulsatile flow in noncircular vessel lumens. We describe a method to quantify wall shear stress in large blood vessels by differentiating velocity interpolation

  19. Quick and effective hyperpolarization of the membrane potential in intact smooth muscle cells of blood vessels by synchronization modulation electric field.

    PubMed

    Zhang, Liping; Fang, Zhihui; Chen, Wei

    2012-06-01

    Blood vessel dilation starts from activation of the Na/K pumps and inward rectifier K channels in the vessel smooth muscle cells, which hyperpolarizes the cell membrane potential and closes the Ca channels. As a result, the intracellular Ca concentration reduces, and the smooth muscle cells relax and the blood vessel dilates. Activation of the Na/K pumps and the membrane potential hyperpolarization plays a critical role in blood vessel functions. Previously, we developed a new technique, synchronization modulation, to control the pump functions by electrically entraining the pump molecules. We have applied the synchronization modulation electric field noninvasively to various intact cells and demonstrated the field-induced membrane potential hyperpolarization. We further applied the electric field to blood vessels and investigated the field induced functional changes of the vessels. In this paper, we report the results in a study of the membrane potential change in the smooth muscle cells of mesenteric blood vessels in response to the oscillating electric field. We found that the synchronization modulation electric field can effectively hyperpolarize the muscle membrane potential quickly in seconds under physiological conditions. PMID:22454211

  20. S1P1 localizes to the colonic vasculature in ulcerative colitis and maintains blood vessel integrity

    PubMed Central

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

    2013-01-01

    Signaling through sphingosine-1-phosphate receptor1 (S1P1) promotes blood vessel barrier function. Degradation of S1P1 results in increased vascular permeability in the lung and may explain side effects associated with administration of FTY720, a functional antagonist of the S1P1 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 S1P1 in blood vessels in the colon has not been investigated. In the present study, we show that S1P1 is overexpressed in the colonic mucosa of UC patients. This increase in S1P1 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 S1P1 is critical to maintaining colonic vascular integrity and may play a role in UC pathogenesis. PMID:23296878

  1. Strengthening Hip Muscles May Ease Calf Pain from Blood Vessel Disease

    MedlinePLUS

    ... parts of the body to narrow, restricting blood flow. This can lead to changes in skin color, ... predict that it is from disuse and blood flow restriction to the muscles," Kakihana said. There are ...

  2. Multi-scale finite element analyses for stress and strain evaluations of braid fibril artificial blood vessel and smooth muscle cell.

    PubMed

    Nakamachi, Eiji; Uchida, Takahiro; Kuramae, Hiroyuki; Morita, Yusuke

    2014-08-01

    In this study, we developed a multi-scale finite element (FE) analysis code to obtain the stress and strain that occurred in the smooth muscle cell (SMC) at micro-scale, which was seeded in the real fabricated braid fibril artificial blood vessel. This FE code can predict the dynamic response of stress under the blood pressure loading. We try to establish a computer-aided engineering (CAE)-driven scaffold design technique for the blood vessel regeneration. Until now, there occurred the great progresses for the endothelial cell activation and intima layer regeneration in the blood vessel regeneration study. However, there remains the difficulty of the SMC activation and media layer regeneration. Therefore, many researchers are now studying to elucidate the fundamental mechanism of SMC activation and media layer regeneration by using the biomechanical technique. As the numerical tool, we used the dynamic-explicit FE code PAM-CRASH, ESI Ltd. For the material models, the nonlinear viscoelastic constitutive law was adapted for the human blood vessel, SMC and the extra-cellular matrix, and the elastic law for the polyglycolic acid (PGA) fiber. Through macro-FE and micro-FE analyses of fabricated braid fibril tubes by using PGA fiber under the combined conditions of the orientation angle and the pitch of fiber, we searched an appropriate structure for the stress stimulation for SMC functionalization. Objectives of this study are indicated as follows: 1. to analyze the stress and strain of the human blood vessel and SMC, and 2. to calculate stress and strain of the real fabricated braid fibril artificial blood vessel and SMC to search an appropriate PGA fiber structure under combined conditions of PGA fiber numbers, 12 and 24, and the helical orientation angles of fiber, 15, 30, 45, 60, and 75 degrees. Finally, we found a braid fibril tube, which has an angle of 15 degree and 12 PGA fibers, as a most appropriate artificial blood vessel for SMC functionalization. PMID:24599892

  3. Effect of Antiprogesterone RU486 on VEGF Expression and Blood Vessel Remodeling on Ovarian Follicles before Ovulation

    PubMed Central

    Berardinelli, Paolo; Russo, Valentina; Bernabò, Nicola; Di Giacinto, Oriana; Mattioli, Mauro; Barboni, Barbara

    2014-01-01

    Background The success of ovarian follicle growth and ovulation is strictly related to the development of an adequate blood vessel network required to sustain the proliferative and endocrine functions of the follicular cells. Even if the Vascular Endothelial Growth Factor (VEGF) drives angiogenesis before ovulation, the local role exerted by Progesterone (P4) remains to be clarified, in particular when its concentration rapidly increases before ovulation. Aim This in vivo study was designed to clarify the effect promoted by a P4 receptor antagonist, RU486, on VEGF expression and follicular angiogenesis before ovulation, in particular, during the transition from pre to periovulatory follicles induced by human Chorionic Gonadotropins (hCG) administration. Material and Methods Preovulatory follicle growth and ovulation were pharmacologically induced in prepubertal gilts by combining equine Chorionic Gonadotropins (eCG) and hCG used in the presence or absence of RU486. The effects on VEGF expression were analyzed using biochemical and immunohistochemical studies, either on granulosa or on theca layers of follicles isolated few hours before ovulation. This angiogenic factor was also correlated to follicular morphology and to blood vessels architecture. Results and Conclusions VEGF production, blood vessel network and follicle remodeling were impaired by RU486 treatment, even if the cause-effect correlation remains to be clarified. The P4 antagonist strongly down-regulated theca VEGF expression, thus, preventing most of the angiogenic follicle response induced by hCG. RU486-treated follicles displayed a reduced vascular area, a lower rate of endothelial cell proliferation and a reduced recruitment of perivascular mural cells. These data provide important insights on the biological role of RU486 and, indirectly, on steroid hormones during periovulatory follicular phase. In addition, an in vivo model is proposed to evaluate how periovulatory follicular angiogenesis may affect the functionality of the corpus luteum (CL) and the success of pregnancy. PMID:24756033

  4. Automatic extraction of blood vessels in the retinal vascular tree using multiscale medialness.

    PubMed

    Ben Abdallah, Mariem; Malek, Jihene; Azar, Ahmad Taher; Montesinos, Philippe; Belmabrouk, Hafedh; Esclarín Monreal, Julio; Krissian, Karl

    2015-01-01

    We propose an algorithm for vessel extraction in retinal images. The first step consists of applying anisotropic diffusion filtering in the initial vessel network in order to restore disconnected vessel lines and eliminate noisy lines. In the second step, a multiscale line-tracking procedure allows detecting all vessels having similar dimensions at a chosen scale. Computing the individual image maps requires different steps. First, a number of points are preselected using the eigenvalues of the Hessian matrix. These points are expected to be near to a vessel axis. Then, for each preselected point, the response map is computed from gradient information of the image at the current scale. Finally, the multiscale image map is derived after combining the individual image maps at different scales (sizes). Two publicly available datasets have been used to test the performance of the suggested method. The main dataset is the STARE project's dataset and the second one is the DRIVE dataset. The experimental results, applied on the STARE dataset, show a maximum accuracy average of around 94.02%. Also, when performed on the DRIVE database, the maximum accuracy average reaches 91.55%. PMID:25977682

  5. Automatic Extraction of Blood Vessels in the Retinal Vascular Tree Using Multiscale Medialness

    PubMed Central

    Malek, Jihene; Montesinos, Philippe; Belmabrouk, Hafedh; Esclarín Monreal, Julio; Krissian, Karl

    2015-01-01

    We propose an algorithm for vessel extraction in retinal images. The first step consists of applying anisotropic diffusion filtering in the initial vessel network in order to restore disconnected vessel lines and eliminate noisy lines. In the second step, a multiscale line-tracking procedure allows detecting all vessels having similar dimensions at a chosen scale. Computing the individual image maps requires different steps. First, a number of points are preselected using the eigenvalues of the Hessian matrix. These points are expected to be near to a vessel axis. Then, for each preselected point, the response map is computed from gradient information of the image at the current scale. Finally, the multiscale image map is derived after combining the individual image maps at different scales (sizes). Two publicly available datasets have been used to test the performance of the suggested method. The main dataset is the STARE project's dataset and the second one is the DRIVE dataset. The experimental results, applied on the STARE dataset, show a maximum accuracy average of around 94.02%. Also, when performed on the DRIVE database, the maximum accuracy average reaches 91.55%. PMID:25977682

  6. Fasciocutaneous vessels

    Microsoft Academic Search

    G. C. Cormack; B. G. H. Lamberty

    1984-01-01

    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

  7. Effect of blood vessel segmentation on the outcome of electroporation-based treatments of liver tumors.

    PubMed

    Mar?an, Marija; Kos, Bor; Miklav?i?, Damijan

    2015-01-01

    Electroporation-based treatments rely on increasing the permeability of the cell membrane by high voltage electric pulses applied to tissue via electrodes. To ensure that the whole tumor is covered with sufficiently high electric field, accurate numerical models are built based on individual patient anatomy. Extraction of patient's anatomy through segmentation of medical images inevitably produces some errors. In order to ensure the robustness of treatment planning, it is necessary to evaluate the potential effect of such errors on the electric field distribution. In this work we focus on determining the effect of errors in automatic segmentation of hepatic vessels on the electric field distribution in electroporation-based treatments in the liver. First, a numerical analysis was performed on a simple 'sphere and cylinder' model for tumors and vessels of different sizes and relative positions. Second, an analysis of two models extracted from medical images of real patients in which we introduced variations of an error of the automatic vessel segmentation method was performed. The results obtained from a simple model indicate that ignoring the vessels when calculating the electric field distribution can cause insufficient coverage of the tumor with electric fields. Results of this study indicate that this effect happens for small (10 mm) and medium-sized (30 mm) tumors, especially in the absence of a central electrode inserted in the tumor. The results obtained from the real-case models also show higher negative impact of automatic vessel segmentation errors on the electric field distribution when the central electrode is absent. However, the average error of the automatic vessel segmentation did not have an impact on the electric field distribution if the central electrode was present. This suggests the algorithm is robust enough to be used in creating a model for treatment parameter optimization, but with a central electrode. PMID:25941806

  8. In-vessel co-composting of horse stable bedding waste and blood meal at different C\\/N ratios: process evaluation

    Microsoft Academic Search

    Jonathan W. C. Wong; Ammaiyappan Selvam; Zhenyong Zhao; Obuli. P. Karthikeyan; Shuk Man Yu; Alex C. W. Law; Patricia C. P. Chung

    2012-01-01

    Abattoir blood meal is rich in nitrogen and its potential as a co-composting material for horse stable bedding waste was evaluated at two C\\/N ratios – 32 (LBM, low blood meal) and 16 (HBM, high blood meal) – to improve the nutrient contents of the final compost. The mix was composted for 7 days in a 10 tonne\\/day in-vessel composter

  9. Investigation of Blood Flow and the Effect of Vasoactive Substances in Cutaneous Blood Vessels of "Xenopus Laevis"

    ERIC Educational Resources Information Center

    Škorjanc, Aleš; Belušic, Gregor

    2015-01-01

    In the present study, a preparation of frog skin was presented, which can be used to demonstrate the basic concepts of blood flow regulation in a very clear and attractive way to high school and university students. In a freshly euthanized "Xenopus," a patch of abdominal skin was exposed from the internal side and viewed with a USB…

  10. Biophysical Properties of Scaffolds Modulate Human Blood Vessel Formation from Circulating Endothelial Colony-Forming Cells

    NASA Astrophysics Data System (ADS)

    Critser, Paul J.; Yoder, Mervin C.

    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.

  11. VEGF signalling controls GnRH neuron survival via NRP1 independently of KDR and blood vessels.

    PubMed

    Cariboni, Anna; Davidson, Kathryn; Dozio, Elena; Memi, Fani; Schwarz, Quenten; Stossi, Fabio; Parnavelas, John G; Ruhrberg, Christiana

    2011-09-01

    Gonadotropin-releasing hormone (GnRH) neurons are neuroendocrine cells that are born in the nasal placode during embryonic development and migrate through the nose and forebrain to the hypothalamus, where they regulate reproduction. Many molecular pathways that guide their migration have been identified, but little is known about the factors that control the survival of the migrating GnRH neurons as they negotiate different environments. We previously reported that the class 3 semaphorin SEMA3A signals through its neuropilin receptors, NRP1 and NRP2, to organise the axons that guide migrating GnRH neurons from their birthplace into the brain. By combining analysis of genetically altered mice with in vitro models, we show here that the alternative neuropilin ligand VEGF164 promotes the survival of migrating GnRH neurons by co-activating the ERK and AKT signalling pathways through NRP1. We also demonstrate that survival signalling relies on neuronal, but not endothelial, NRP1 expression and that it occurs independently of KDR, the main VEGF receptor in blood vessels. Therefore, VEGF164 provides survival signals directly to developing GnRH neurons, independently of its role in blood vessels. Finally, we show that the VEGF164-mediated neuronal survival and SEMA3A-mediated axon guidance cooperate to ensure that migrating GnRH neurons reach the brain. Thus, the loss of both neuropilin ligands leads to an almost complete failure to establish the GnRH neuron system. PMID:21828096

  12. Generation of High Contrast Image from X-ray Scene Images of Brain Blood Vessel of Rat

    NASA Astrophysics Data System (ADS)

    Kuze, Yasuyuki; Kondoh, Takeshi; Saitoh, Fumihiko

    The X-ray scene image of a brain blood vessel of a rat can be shot by using SPring-8 that is a high-performance X-ray sensing system. However, the contrast of the scene image is not enough visually. Even if the contrast of a scene image is poor, a single image that has good contrast can be generated by accumulating all frames in the scene image. However, objects in the scene image must be fixed to use the method. This paper proposes a method to generate a single image with good contrast from X-ray scene images of brain blood vessel of a rat. The partial optimal frames that are useful for generating an output image with good contrast are selected in all frames and the selected frames are accumulated after optimal two-dimensional moving. The genetic algorithm is applied to optimize the selection and moving of frames. The experimental results show that the generated output image by the proposed method had good contrast, clearness and fewer noises in comparison with the generated image by the conventional method.

  13. CO2 laser soldering of arteriotomy incisions in blood vessels of rats using a temperature-controlled fiber optic system

    NASA Astrophysics Data System (ADS)

    Leshem, David; Vasilyev, Tamar; Ravid, Avi; Gat, Andrea; Kariv, Naam; Katzir, Abraham; Gur, Eyal

    2003-06-01

    Background and objectives: Conventional methods for microvascular anastomosis are normally based on suturing, using special thin nylon sutures. These methods suffer from major drawbacks, which include: anastomosis, which is not watertight, and sutures or clips that cause an inflammatory response. In order to obtain better results, we introduced a procedure based on CO2 laser soldering. We tested the system on arteriotomy incisions in rat blood vessels, in vivo. Materials and methods: We used a fiber optic based laser soldering system, with a temperature control capability. Arteriotomy incisions of lengths 4+/-1mm were performed on the femoral arteries of 48 wistar rats: 24 rats in the control group (suture) and 24 rats in the test group (laser soldering). We conducted two follow-up periods: 7 days and 21 days after the surgical procedure, for each group. Flow tests and histology examination were done in order to evaluate the quality of the procedures. Results: The patency rate was 84% for both groups, soldered and sutured. The sutured group showed a significant foreign body reaction (p < 0.05), which was not observed in the soldered group. We found no evidence of thermal damage in the soldered blood vessels. Conclusions: We can conclude that laser soldering is a less traumatic procedure, compared with the conventional suturing technique. It is potentially a faster technique and easier to master.

  14. Spatial and structural interrelationships between secretory cells of the subcommissural organ and blood vessels. An immunocytochemical study.

    PubMed

    Rodríguez, E M; Oksche, A; Hein, S; Rodríguez, S; Yulis, R

    1984-01-01

    In 76 specimens (amphibians, reptilians, mammals) belonging to 25 different vertebrate species, the region of the subcommissural organ (SCO) was investigated with the use of a primary antiserum raised against an extract of bovine Reissner's fiber + the immunoperoxidase procedure according to Sternberger et al. (1970). In the SCO of a toad (Bufo arenarum) and several species of reptiles (lacertilians, ophidians, crocodilians), the ependymal cells were the only type of secretory cell displaying vascular contacts, whereas in mammals ependymal and hypendymal cells established intimate spatial contacts with blood vessels. In Bufo arenarum, but especially in the reptilian species examined, the ependymo-vascular relationship was exerted by a population of ependymal cells having a rather constant location within the SCO and projecting to capillaries that showed a remarkably constant pattern of anatomical distribution. In the SCO of mammals the modality and degree of the structural relationships between secretory cells and blood vessels varied greatly from species to species. In the SCO of the armadillo and dog the secretory tissue was organized as a thick, highly vascularized layer with most of the cells oriented toward the capillaries. A rather opposite situation was found in the SCO of New- and Old-World monkeys, where vascular contacts were restricted to a few ependymal cells. PMID:6435877

  15. The influence of surrogate blood vessels on the impact response of a physical model of the brain.

    PubMed

    Parnaik, Yednesh; Beillas, Philippe; Demetropoulos, Constantine K; Hardy, Warren N; Yang, King H; King, Albert I

    2004-11-01

    Cerebral blood vessels are an integral part of the brain and may play a role in the response of the brain to impact. The purpose of this study was to quantify the effects of surrogate vessels on the deformation patterns of a physical model of the brain under various impact conditions. Silicone gel and tubing were used as surrogates for brain tissue and blood vessels, respectively. Two aluminum cylinders representing a coronal section of the brain were constructed. One cylinder was filled with silicone gel only, and the other was filled with silicone gel and silicone tubing arranged in the radial direction in the peripheral region. An array of markers was embedded in the gel in both cylinders to facilitate strain calculation via high-speed video analysis. Both cylinders were simultaneously subjected to a combination of linear and angular acceleration using a two-segment pendulum. Marker motion was tracked, and maximum shear strain (MSS) and maximum principal strain (MPS) were calculated using markers clustered in groups of three. Four test series were conducted. Peak angular acceleration varied from 2,600 to 26,000 rad/s2, and peak angular speed varied from 17 to 29 rad/s. For a given impact condition, the test-to-test variation of these values was less than 5.5%. For all clusters, the peak MSS and peak MPS for both physical models were less than 26% and 32%, respectively. For 90% of the cluster locations, the absolute value of the difference in peak MSS and peak MPS between the physical models was 4% and 6%, respectively. In the physical model with tubing, strain tended to decrease in the periphery (near to the tubing), while it tended to increase toward the center (away from the tubing). Strain amplitudes were found to be sensitive to the peak angular speeds. In general, this study suggests that the vasculature could influence the deformation response of the brain. PMID:17230270

  16. Computational blood flow and vessel wall modeling in a CT-based thoracic aorta after stent-graft implantation

    NASA Astrophysics Data System (ADS)

    Hazer, Dilana; Stoll, Markus; Schmidt, Eduard; Richter, Goetz-M.; Dillmann, Rüdiger

    2010-03-01

    Abnormal blood flow conditions and structural fatigue within stented vessels may lead to undesired failure causing death to the patient. Image-based computational modeling provides a physical and realistic insight into the patientspecific biomechanics and enables accurate predictive simulations of development, growth and failure of cardiovascular diseases as well as associated risks. Controlling the efficiency of an endovascular treatment is necessary for the evaluation of potential complications and predictions on the assessment of the pathological state. In this paper we investigate the effects of stent-graft implantation on the biomechanics in a patient-specific thoracic aortic model. The patient geometry and the implanted stent-graft are obtained from morphological data based on a CT scan performed during a controlling routine. Computational fluid dynamics (CFD) and computational structure mechanics (CSM) simulations are conducted based on the finite volume method (FVM) and on the finite element method (FEM) to compute the hemodynamics and the elastomechanics within the aortic model, respectively. Physiological data based on transient pressure and velocity profiles are used to set the necessary boundary conditions. Further, the effects of various boundary conditions and definition of contact interactions on the numerical stability of the blood flow and the vessel wall simulation results are also investigated. The quantification of the hemodynamics and the elastomechanics post endovascular intervention provides a realistic controlling of the state of the stented vessel and of the efficiency of the therapy. Consequently, computational modeling would help in evaluating individual therapies and optimal treatment strategies in the field of minimally invasive endovascular surgery.

  17. Effect of gravitation stress and hypokinesia on blood vessels of the testicle

    NASA Technical Reports Server (NTRS)

    Palazhchenko, E. F.

    1979-01-01

    Rabbits were exposed to single maximum endurable stresses of cranio-caudal direction, hypokinesia for periods of one to eight weeks, and hypokinesia followed by gravitation stresses. The stresses caused dilatation of vessels, greater sinuosity, and occasional ruptures of the walls and extravasation. The greater part of the capillaries were dilated; the greatest part constricted. In hypokinesia there was an increasing atrophy of the testes. Significant results are reported.

  18. Abnormal blood vessel development and lethality in embryos lacking a single VEGF allele

    Microsoft Academic Search

    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

    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

  19. Imaging of subcutaneous blood vessels and flow velocity profiles by optical coherence tomography

    Microsoft Academic Search

    M. Bonesi; S. G. Proskurin; I. V. Meglinski

    2010-01-01

    We have applied a compact low power rapid scanning Doppler Optical Coherence Tomography system to monitor multi-dimensional\\u000a velocity profiles within the complex vessels and simultaneous real-time non-invasive imaging of skin tissues morphology in\\u000a vivo, in the wavelength range of 1.3–1.5 nm. Optical clearing of skin tissues has been utilized to achieve depth of OCT images\\u000a up to 1.7 mm. Current

  20. Small-field angiographic imaging of tumor blood vessels using synchrotron radiation

    Microsoft Academic Search

    K. Umetani; T. Yamashita; N. Maehara; S. Imai; Y. Kajihara

    2001-01-01

    Microangiography with about 10 ?m resolution has been carried out for depicting angiogenic vessels in a rabbit model of cancer using a high-resolution detector and a third generation synchrotron radiation source at SPring-8. In synchrotron radiation radiography, a long source-to-object distance and a small source spot can produce high-resolution images. VX2 carcinoma had been transplanted in a rabbit auricle. By

  1. Endothelial cell hyperproliferation and stratification in uteroplacental blood vessels of the black mastiff bat, Molossus rufus.

    PubMed

    Rasweiler, J J; Badwaik, N K; Salame, G; Abulafia, O

    2011-09-01

    Placentation was studied histologically and immunocytochemically in black mastiff bats obtained at frequent intervals throughout pregnancy. These were bred in a captive colony or collected from a reproductively-synchronized wild population. During late pregnancy, the single fetus was largely sustained by a discoidal, hemochorial placenta located at the cranial end of the right uterine horn. This invariant positioning was determined by a vascular tuft that developed there both during early pregnancy and non-pregnant cycles. This provided a scaffold for early placental morphogenesis. As development proceeded, small arterioles and venules serving the tuft were converted to large uteroplacental vessels. Within the base of the placenta, these became lined by an unusual vascular epithelium composed of intermingled patches of multilayered endothelial cells and cytotrophoblast. Initially, the endothelium became multilayered by hypertrophy, proliferation, and infolding of its basal lamina. These created endothelial bilayers usually insinuated between basal laminae. The development of temporary gaps in the laminae then permitted further enlargement of the vessels and proliferation of the endothelial cells as monolayer sheets or chains. The latter were interconnected, forming a complex, stratified, cellular network associated with a prominent meshwork of basal laminae. Throughout much of pregnancy, these endothelial cells were cuboidal to columnar and possessed an abundance of basal glycoprotein granules presumably containing basal lamina precursors. The cells also expressed vimentin and frequently von Willebrand factor, but not cytokeratins or desmin. Pronounced thickening of the endothelia and amplification of their basal laminae likely evolved to greatly strengthen the walls of the uteroplacental vessels. PMID:21764447

  2. Effect of gravitational overloads, hypokinesia and hypodynamia on the vessels of the pulmonary blood circuit

    NASA Technical Reports Server (NTRS)

    Kasimtsev, A. A.

    1980-01-01

    Vessels of the pulmonary circuit are studied under normal conditions, in exposure to single stress or continuous threshold endurable chestspine gravitational stresses, and one to eight weak hypokinesia and hypodynamic effects followed by stress. Examination methods include rentgenography and microrentgenography, clearing, and histology. In exposure to gravitational stress the distal portions of the arterial vessels of the 3 and 4 orders constrict, while all veins dilate. Sinuosity of all vessels is noted. The volume of the capillary bed increases and signs of perivascular edema occur. Due to hypokinesia and hypodynamia the arteries constricted and the arterial bed becomes poor. The veins of all orders dilate and the volume of the capillary bed increases. The changes grew greater the longer the terms of hypodyamic effects. Successive combination of hypokinesia and hypodynamia and gravitational stresses cause more pronounced changes than separate effects of these two factors and result in great deformity of the vascular walls, including their rupture and penetration of formed elements beyond the limits of the vascular bed.

  3. Automated detection of kinks from blood vessels for optic cup segmentation in retinal images

    NASA Astrophysics Data System (ADS)

    Wong, D. W. K.; Liu, J.; Lim, J. H.; Li, H.; Wong, T. Y.

    2009-02-01

    The accurate localization of the optic cup in retinal images is important to assess the cup to disc ratio (CDR) for glaucoma screening and management. Glaucoma is physiologically assessed by the increased excavation of the optic cup within the optic nerve head, also known as the optic disc. The CDR is thus an important indicator of risk and severity of glaucoma. In this paper, we propose a method of determining the cup boundary using non-stereographic retinal images by the automatic detection of a morphological feature within the optic disc known as kinks. Kinks are defined as the bendings of small vessels as they traverse from the disc to the cup, providing physiological validation for the cup boundary. To detect kinks, localized patches are first generated from a preliminary cup boundary obtained via level set. Features obtained using edge detection and wavelet transform are combined using a statistical approach rule to identify likely vessel edges. The kinks are then obtained automatically by analyzing the detected vessel edges for angular changes, and these kinks are subsequently used to obtain the cup boundary. A set of retinal images from the Singapore Eye Research Institute was obtained to assess the performance of the method, with each image being clinically graded for the CDR. From experiments, when kinks were used, the error on the CDR was reduced to less than 0.1 CDR units relative to the clinical CDR, which is within the intra-observer variability of 0.2 CDR units.

  4. The influence of red blood cell scattering in optical pathways of retinal vessel oximetry

    NASA Astrophysics Data System (ADS)

    LeBlanc, Serge Emile

    The ability to measure the oxygen saturation, oximetry, of retinal blood both non-invasively and in-vivo has been a goal of eye research for years. Retinal oximetry can in principle be achieved from the measurement of the reflectance spectrum of the ocular fundus. Oximetry calculations are however complicated by the scattering of red blood cells, the different pathways of light through blood and the ocular tissues that light interacts with before exiting the eye. The goal of this thesis was to investigate the influence of red blood cell scattering for different light paths relevant to retinal oximetry. Results of in-vitro whole blood experiments found calculated oxygen saturation differences between blood samples measured under different retinal light paths, and these differences did not depend on the absorbance path length. We also showed that the calculated oxygen saturation value determined by a multiple linear regression Beer-Lambert absorbance model depended on the wavelength range chosen for analysis. The wavelength dependency on the calculated oxygen saturation value is due in part to the correlation that exists between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficient spectra and to errors in the assumptions built into the Beer-Lambert absorbance model. A wavelength region with low correlation between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficients was found that is hypothesized to be a good range to calculate oxygen saturation using a multiple linear regression approach.

  5. Vascular Endothelial Growth Factor Receptor Expression During Embryogenesis and Tissue Repair Suggests a Role in Endothelial Differentiation and Blood Vessel Growth

    NASA Astrophysics Data System (ADS)

    Peters, Kevin G.; de Vries, Carlie; Williams, Lewis T.

    1993-10-01

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

  6. Comparison of cellular architecture, axonal growth, and blood vessel formation through cell-loaded polymer scaffolds in the transected rat spinal cord.

    PubMed

    Madigan, Nicolas N; Chen, Bingkun K; Knight, Andrew M; Rooney, Gemma E; Sweeney, Eva; Kinnavane, Lisa; Yaszemski, Michael J; Dockery, Peter; O'Brien, Timothy; McMahon, Siobhan S; Windebank, Anthony J

    2014-11-01

    The use of multichannel polymer scaffolds in a complete spinal cord transection injury serves as a deconstructed model that allows for control of individual variables and direct observation of their effects on regeneration. In this study, scaffolds fabricated from positively charged oligo[poly(ethylene glycol)fumarate] (OPF(+)) hydrogel were implanted into rat spinal cords following T9 complete transection. OPF(+) scaffold channels were loaded with either syngeneic Schwann cells or mesenchymal stem cells derived from enhanced green fluorescent protein transgenic rats (eGFP-MSCs). Control scaffolds contained extracellular matrix only. The capacity of each scaffold type to influence the architecture of regenerated tissue after 4 weeks was examined by detailed immunohistochemistry and stereology. Astrocytosis was observed in a circumferential peripheral channel compartment. A structurally separate channel core contained scattered astrocytes, eGFP-MSCs, blood vessels, and regenerating axons. Cells double-staining with glial fibrillary acid protein (GFAP) and S-100 antibodies populated each scaffold type, demonstrating migration of an immature cell phenotype into the scaffold from the animal. eGFP-MSCs were distributed in close association with blood vessels. Axon regeneration was augmented by Schwann cell implantation, while eGFP-MSCs did not support axon growth. Methods of unbiased stereology provided physiologic estimates of blood vessel volume, length and surface area, mean vessel diameter, and cross-sectional area in each scaffold type. Schwann cell scaffolds had high numbers of small, densely packed vessels within the channels. eGFP-MSC scaffolds contained fewer, larger vessels. There was a positive linear correlation between axon counts and vessel length density, surface density, and volume fraction. Increased axon number also correlated with decreasing vessel diameter, implicating the importance of blood flow rate. Radial diffusion distances in vessels significantly correlated to axon number as a hyperbolic function, showing a need to engineer high numbers of small vessels in parallel to improving axonal densities. In conclusion, Schwann cells and eGFP-MSCs influenced the regenerating microenvironment with lasting effect on axonal and blood vessel growth. OPF(+) scaffolds in a complete transection model allowed for a detailed comparative, histologic analysis of the cellular architecture in response to each cell type and provided insight into physiologic characteristics that may support axon regeneration. PMID:24854680

  7. Simulation of blood flow in deformable vessels using subject-specific geometry and spatially varying wall properties

    PubMed Central

    Xiong, Guanglei; Figueroa, C. Alberto; Xiao, Nan; Taylor, Charles A.

    2011-01-01

    SUMMARY Simulation of blood flow using image-based models and computational fluid dynamics has found widespread application to quantifying hemodynamic factors relevant to the initiation and progression of cardiovascular diseases and for planning interventions. Methods for creating subject-specific geometric models from medical imaging data have improved substantially in the last decade but for many problems, still require significant user interaction. In addition, while fluid–structure interaction methods are being employed to model blood flow and vessel wall dynamics, tissue properties are often assumed to be uniform. In this paper, we propose a novel workflow for simulating blood flow using subject-specific geometry and spatially varying wall properties. The geometric model construction is based on 3D segmentation and geometric processing. Variable wall properties are assigned to the model based on combining centerline-based and surface-based methods. We finally demonstrate these new methods using an idealized cylindrical model and two subject-specific vascular models with thoracic and cerebral aneurysms. PMID:21765984

  8. Expression of the Growth Factor Progranulin in Endothelial Cells Influences Growth and Development of Blood Vessels: A Novel Mouse Model

    PubMed Central

    Toh, Huishi; Cao, Mingju; Daniels, Eugene; Bateman, Andrew

    2013-01-01

    Progranulin is a secreted glycoprotein that regulates cell proliferation, migration and survival. It has roles in development, tumorigenesis, wound healing, neurodegeneration and inflammation. Endothelia in tumors, wounds and placenta express elevated levels of progranulin. In culture, progranulin activates endothelial proliferation and migration. This suggested that progranulin might regulate angiogenesis. It was, however, unclear how elevated endothelial progranulin levels influence vascular growth in vivo. To address this issue, we generated mice with progranulin expression targeted specifically to developing endothelial cells using a Tie2–promoter/enhancer construct. Three Tie2-Grn mouse lines were generated with varying Tie2-Grn copy number, and were called GrnLo, GrnMid, and GrnHi. All three lines showed increased mortality that correlates with Tie2-Grn copy number, with greatest mortality and lowest germline transmission in the GrnHi line. Death of the transgenic animals occurred around birth, and continued for three days after birth. Those that survived beyond day 3 survived into adulthood. Transgenic neonates that died showed vascular abnormalities of varying severity. Some exhibited bleeding into body cavities such as the pericardial space. Smaller localized hemorrhages were seen in many organs. Blood vessels were often dilated and thin-walled. To establish the development of these abnormalities, we examined mice at early (E10.5–14.5) and later (E15.5–17.5) developmental phases. Early events during vasculogenesis appear unaffected by Tie2-Grn as apparently normal primary vasculature had been established at E10.5. The earliest onset of vascular abnormality was at E15.5, with focal cerebral hemorrhage and enlarged vessels in various organs. Aberrant Tie2-Grn positive vessels showed thinning of the basement membrane and reduced investiture with mural cells. We conclude that progranulin promotes exaggerated vessel growth in vivo, with subsequent effects in the formation of the mural cell layer and weakening of vessel integrity. These results demonstrate that overexpression of progranulin in endothelial cells influences normal angiogenesis in vivo. PMID:23741441

  9. In vivo ?PIV measurements of blood velocity in small vessels of a rat model

    NASA Astrophysics Data System (ADS)

    Leong, Chia Min; Russell, John; Connor, Nadine; Honkanen, Markus; Wei, Timothy

    2009-11-01

    Aging-related muscular changes have been shown to affect voice production. There is correlation between muscular changes and changes in capillary hemodynamics and structure with aging. Alterations in oxygen transport to cells and tissues at the capillary level has been hypothesized as one of the key factors that causes muscular changes thus voice production. Since oxygen transport is related to hemodynamics, we start by measuring blood velocity in capillaries of cremaster muscle of a living rat. The ?PIV technique is adapted for measuring blood velocity where red blood cells are used as `seeding particles'. The accuracy of the ?PIV measurements are determined by comparison with results obtained using other techniques such as particle tracking velocimetry (PTV). Finally, challenges in measuring flow through three-dimensional larynx geometry will be discussed.

  10. Human vasculogenic cells form functional blood vessels and mitigate adverse remodeling after ischemia reperfusion injury in rats

    PubMed Central

    Kang, Kyu-Tae; Coggins, Matthew; Xiao, Chunyang; Rosenzweig, Anthony

    2013-01-01

    Cell-based therapies to restore heart function after infarction have been tested in pre-clinical models and clinical trials with mixed results, and will likely require both contractile cells and a vascular network to support them. We and others have shown that human endothelial colony forming cells (ECFC) combined with mesenchymal progenitor cells (MPC) can be used to “bio-engineer” functional human blood vessels. Here we investigated whether ECFC + MPC form functional vessels in ischemic myocardium and whether this affects cardiac function or remodeling. Myocardial ischemia/reperfusion injury (IRI) was induced in 12-week-old immunodeficient rats by ligation of the left anterior descending coronary artery. After 40 min, myocardium was reperfused and ECFC + MPC (2 × 106 cells, 2:3 ratio) or PBS was injected. Luciferase assays after injection of luciferase-labeled ECFC + MPC showed that 1,500 ECFC were present at day 14. Human ECFC-lined perfused vessels were directly visualized by femoral vein injection of a fluorescently-tagged human-specific lectin in hearts injected with ECFC + MPC but not PBS alone. While infarct size at day 1 was no different, LV dimensions and heart weight to tibia length ratios were lower in cell-treated hearts compared with PBS at 4 months, suggesting post-infarction remodeling was ameliorated by local cell injection. Fractional shortening, LV wall motion score, and fibrotic area were not different between groups at 4 months. However, pressure–volume loops demonstrated improved cardiac function and reduced volumes in cell-treated animals. These data suggest that myocardial delivery of ECFC + MPC at reperfusion may provide a therapeutic strategy to mitigate LV remodeling and cardiac dysfunction after IRI. PMID:23666122

  11. Human vasculogenic cells form functional blood vessels and mitigate adverse remodeling after ischemia reperfusion injury in rats.

    PubMed

    Kang, Kyu-Tae; Coggins, Matthew; Xiao, Chunyang; Rosenzweig, Anthony; Bischoff, Joyce

    2013-10-01

    Cell-based therapies to restore heart function after infarction have been tested in pre-clinical models and clinical trials with mixed results, and will likely require both contractile cells and a vascular network to support them. We and others have shown that human endothelial colony forming cells (ECFC) combined with mesenchymal progenitor cells (MPC) can be used to "bio-engineer" functional human blood vessels. Here we investigated whether ECFC + MPC form functional vessels in ischemic myocardium and whether this affects cardiac function or remodeling. Myocardial ischemia/reperfusion injury (IRI) was induced in 12-week-old immunodeficient rats by ligation of the left anterior descending coronary artery. After 40 min, myocardium was reperfused and ECFC + MPC (2 × 10(6) cells, 2:3 ratio) or PBS was injected. Luciferase assays after injection of luciferase-labeled ECFC + MPC showed that 1,500 ECFC were present at day 14. Human ECFC-lined perfused vessels were directly visualized by femoral vein injection of a fluorescently-tagged human-specific lectin in hearts injected with ECFC + MPC but not PBS alone. While infarct size at day 1 was no different, LV dimensions and heart weight to tibia length ratios were lower in cell-treated hearts compared with PBS at 4 months, suggesting post-infarction remodeling was ameliorated by local cell injection. Fractional shortening, LV wall motion score, and fibrotic area were not different between groups at 4 months. However, pressure-volume loops demonstrated improved cardiac function and reduced volumes in cell-treated animals. These data suggest that myocardial delivery of ECFC + MPC at reperfusion may provide a therapeutic strategy to mitigate LV remodeling and cardiac dysfunction after IRI. PMID:23666122

  12. The corn snake yolk sac becomes a solid tissue filled with blood vessels and yolk-rich endodermal cells

    PubMed Central

    Elinson, Richard P.; Stewart, James R.

    2014-01-01

    The amniote egg was a key innovation in vertebrate evolution because it supports an independent existence in terrestrial environments. The egg is provisioned with yolk, and development depends on the yolk sac for the mobilization of nutrients. We have examined the yolk sac of the corn snake Pantherophis guttatus by the dissection of living eggs. In contrast to the familiar fluid-filled sac of birds, the corn snake yolk sac invades the yolk mass to become a solid tissue. There is extensive proliferation of yolk-filled endodermal cells, which associate with a meshwork of blood vessels. These novel attributes of the yolk sac of corn snakes compared with birds suggest new pathways for the evolution of the amniote egg. PMID:24402715

  13. First two cases of living related liver transplantation with complicated anatomy of blood vessels in Beijing

    Microsoft Academic Search

    Wen-Han Wu; Yuan-Lian Wan; Long Lee; Yin-Mo Yang; Yan-Ting Huang; Chao-Long Chen; Sheung-Tat Fan

    AIM: Living related liver transplantation (LRLT) has been developed in response to the paediatric organ donor shortage. Though it has been succeeded in many centers worldwide, the safety of the donor is still a major concern, especially in donors with anatomy variation. We succeeded in performing the first two cases of living related liver transplantation with complicated anatomy of blood

  14. Endothelial Wnt/?-catenin signaling inhibits glioma angiogenesis and normalizes tumor blood vessels by inducing PDGF-B expression

    PubMed Central

    Reis, Marco; Czupalla, Cathrin J.; Ziegler, Nicole; Devraj, Kavi; Zinke, Jenny; Seidel, Sascha; Heck, Rosario; Thom, Sonja; Macas, Jadranka; Bockamp, Ernesto; Fruttiger, Marcus; Taketo, Makoto M.; Dimmeler, Stefanie; Plate, Karl H.

    2012-01-01

    Endothelial Wnt/?-catenin signaling is necessary for angiogenesis of the central nervous system and blood–brain barrier (BBB) differentiation, but its relevance for glioma vascularization is unknown. In this study, we show that doxycycline-dependent Wnt1 expression in subcutaneous and intracranial mouse glioma models induced endothelial Wnt/?-catenin signaling and led to diminished tumor growth, reduced vascular density, and normalized vessels with increased mural cell attachment. These findings were corroborated in GL261 glioma cells intracranially transplanted in mice expressing dominant-active ?-catenin specifically in the endothelium. Enforced endothelial ?-catenin signaling restored BBB characteristics, whereas inhibition by Dkk1 (Dickkopf-1) had opposing effects. By overactivating the Wnt pathway, we induced the Wnt/?-catenin–Dll4/Notch signaling cascade in tumor endothelia, blocking an angiogenic and favoring a quiescent vascular phenotype, indicated by induction of stalk cell genes. We show that ?-catenin transcriptional activity directly regulated endothelial expression of platelet-derived growth factor B (PDGF-B), leading to mural cell recruitment thereby contributing to vascular quiescence and barrier function. We propose that reinforced Wnt/?-catenin signaling leads to inhibition of angiogenesis with normalized and less permeable vessels, which might prove to be a valuable therapeutic target for antiangiogenic and edema glioma therapy. PMID:22908324

  15. VEGFR-1 mediates endothelial differentiation and formation of blood vessels in a murine model of infantile hemangioma.

    PubMed

    Boscolo, Elisa; Mulliken, John B; Bischoff, Joyce

    2011-11-01

    Vascular endothelial growth factor receptor-1 (VEGFR-1) is a member of the VEGFR family, and binds to VEGF-A, VEGF-B, and placental growth factor. VEGFR-1 contributes to tumor growth and metastasis, but its role in the pathological formation of blood vessels is still poorly understood. Herein, we used infantile hemangioma (IH), the most common tumor of infancy, as a means to study VEGFR-1 activation in pathological vasculogenesis. IH arises from stem cells (HemSCs) that can form the three most prominent cell types in the tumor: endothelial cells, pericytes, and adipocytes. HemSCs can recapitulate the IH life cycle when injected in immuncompromised mice, and are targeted by corticosteroids, the traditional treatment for IH. We report here that VEGF-A or VEGF-B induces VEGFR-1-mediated ERK1/2 phosphorylation in HemSCs and promotes differentiation of HemSCs to endothelial cells. Studies of VEGFR-2 phosphorylation status and down-regulation of neuropilin-1 in the HemSCs demonstrate that VEGFR-2 and NRP1 are not needed for VEGF-A- or VEGF-B-induced ERK1/2 activation. U0216-mediated blockade of ERK1/2 phosphorylation or shRNA-mediated suppression of VEGFR-1 prevents HemSC-to-EC differentiation. Furthermore, the down-regulation of VEGFR-1 in the HemSCs results in decreased formation of blood vessels in vivo and reduced ERK1/2 activation. Thus, our study reveals a critical role for VEGFR-1 in the HemSC-to-EC differentiation that underpins pathological vasculogenesis in IH. PMID:21945324

  16. Assessing blood vessel abnormality via extracting scattering coefficients from OCT images

    NASA Astrophysics Data System (ADS)

    Levitz, David; Andersen, Claus B.; Frosz, Michael H.; Thrane, Lars; Hansen, Peter R.; Jorgensen, Thomas M.; Andersen, Peter E.

    2003-10-01

    Background: Coronary artery disease (CAD) is the leading cause of mortality and morbidity in the industrialized world. Optical coherence tomography (OCT) is a high-resolution intravascular imaging technology with a potential for in vivo plaque characterization. Although structural remodeling of the arterial vessel wall during plaque development can change tissue optical scattering properties, very limited evidence is available on the exact optical scattering properties of plaques. The scattering coefficient, ?s, and the anisotropy factor, g, can be derived from OCT images by fitting a theoretical model to individual depth-scans. The aim of the current study was to use this method to examine by OCT the scattering properties of human arteries with different stages of atherosclerotic lesion development. Methods: Normal (n=4), lipid-rich (n=4), and fibrous (n=3) aortic blocks as classified by parallel histopathologic examination were obtained within 24 hours of death and imaged by OCT. The intima was located in the OCT images, and then further split into 115 blocks (41 normal, 40 lipid-rich, and 34 fibrous) of adjacent OCT depth-scans transversely spanning ~200-300 ?m. Scattering signals from each block were averaged and fit to the theoretical model. From these fittings, ?s and g were extracted. Results and Discussion: The optical scattering properties of normal aortic intima were quite different from lipid-rich and fibrous lesions, respectively. We discovered that the normal intima was generally highly forward scattering, i.e., with 0.917vessels were much less so. Furthermore, normal vessels usually had 15

  17. Iodine imaging using spectral analysis. [radiography for visualization of small blood vessels

    NASA Technical Reports Server (NTRS)

    Macovski, A.

    1978-01-01

    Existing radiographic imaging systems provide images which represent an integration or averaging over the energy spectrum. In order to provide noninvasive angiography it is necessary to image the relatively small amounts of iodine which are available following an intravenous administration. This is accomplished by making use of the special spectral characteristics of iodine. Two methods will be presented. One involves a special grating for encoding the iodine information in the form of a fine line pattern. This is subsequently decoded to provide images of iodinated structures which are otherwise almost invisible. The second method utilizes a scanned X-ray beam which is rapidly switched in the high energy region. In this region, iodine experiences significant variations in the attenuation coefficient while bone and soft tissue do not. An efficient and accurate X-ray detector can be used with scanned X-ray beams. This provides a high degree of sensitivity enabling the visualization of small vessels containing relatively dilute iodine.

  18. In vivo photoacoustic imaging of blood vessels with a pulsed laser diode

    Microsoft Academic Search

    Roy G. M. Kolkman; Wiendelt Steenbergen; Ton G. van Leeuwen

    2006-01-01

    Photoacoustic imaging is a hybrid imaging modality that is based on the detection of acoustic waves generated by absorption of pulsed light by tissue chromophores such as hemoglobin in blood. For this technique, usually large and costly Q-switched Nd:YAG lasers are used. These lasers provide a pulse energy of at least several milliJoules. In search of alternative light sources, we

  19. High-contrast real-time optoacoustic imaging of subcutaneous blood vessels

    Microsoft Academic Search

    M. Fournelle; H.-J. Welsch; H. Fonfara; H. Hewener; C. Günther; W. Bost; R. Lemor

    \\u000a In optoacoustic imaging, acoustical signals are generated when short light pulses are absorbed in tissue. Thus, the higher\\u000a the absorption coefficient of the investigated tissue is, the stronger the optoacoustic signals will be. The absorption of\\u000a blood in the NIR is several orders of magnitude higher than of other tissue types, so that it can be imaged with very high

  20. Ex vivo blood vessel imaging using ultrasound-modulated optical microscopy

    PubMed Central

    Kothapalli, Sri-Rajasekhar; Wang, Lihong V.

    2009-01-01

    Recently we developed ultrasound-modulated optical microscopy (UOM) based on a long-cavity confocal Fabry-Perot interferometer (CFPI) [J. Biomed. Opt. 13(5), 0504046, (2008)]. This interferometer is used for real time detection of multiply scattered light modulated by high frequency (30 MHz to 75 MHz) ultrasound pulses propagating in an optically strongly scattering medium. In this article, we use this microscope to study the dependence of ultrasound-modulated optical signals on the optical absorption and scattering properties of objects embedded about 3 mm deep in tissue mimicking phantoms. These results demonstrate that UOM has the potential to map both optical absorption and scattering contrast. Most importantly, for the first time in the field of ultrasound-modulated optical imaging, we imaged blood vasculature in highly scattering tissue samples from a mouse and a rat. Therefore UOM could be a promising tool to study the morphology of blood vasculature and blood-associated functional parameters, such as oxygen saturation. PMID:19256703

  1. Viscous flow past a collapsible channel as a model for self-excited oscillation of blood vessels.

    PubMed

    Tang, Chao; Zhu, Luoding; Akingba, George; Lu, Xi-Yun

    2015-07-16

    Motivated by collapse of blood vessels for both healthy and diseased situations under various circumstances in human body, we have performed computational studies on an incompressible viscous fluid past a rigid channel with part of its upper wall being replaced by a deformable beam. The Navier-Stokes equations governing the fluid flow are solved by a multi-block lattice Boltzmann method and the structural equation governing the elastic beam motion by a finite difference method. The mutual coupling of the fluid and solid is realized by the momentum exchange scheme. The present study focuses on the influences of the dimensionless parameters controlling the fluid-structure system on the collapse and self-excited oscillation of the beam and fluid dynamics downstream. The major conclusions obtained in this study are described as follows. The self-excited oscillation can be intrigued by application of an external pressure on the elastic portion of the channel and the part of the beam having the largest deformation tends to occur always towards the end portion of the deformable wall. The blood pressure and wall shear stress undergo significant variations near the portion of the greatest oscillation. The stretching motion has the most contribution to the total potential elastic energy of the oscillating beam. PMID:25911249

  2. A cellular nonlinear network: real-time technology for the analysis of microfluidic phenomena in blood vessels

    NASA Astrophysics Data System (ADS)

    Sapuppo, F.; Bucolo, M.; Intaglietta, M.; Fortuna, L.; Arena, P.

    2006-02-01

    A new approach to the observation and analysis of dynamic structural and functional parameters in the microcirculation is described. The new non-invasive optical system is based on cellular nonlinear networks (CNNs), highly integrated analogue processor arrays whose processing elements, the cells, interact directly within a finite local neighbourhood. CNNs, thanks to their parallel processing feature and spatially distributed structure, are widely used to solve high-speed image processing and recognition problems and in the description and modelling of biological dynamics through the solution of time continuous partial differential equations (PDEs). They are therefore considered extremely suitable for spatial-temporal dynamic characterization of fluidic phenomena at micrometric to nanometric scales, such as blood flow in microvessels and its interaction with the cells of the vessel wall. A CNN universal machine (CNN-UM) structure was used to implement, via simulation and hardware (ACE16k), the algorithms to determine the functional capillarity density (FCD) and red blood cell velocity (RBCV) in capillaries obtained by intravital microscopy during in vivo experiments on hamsters. The system exploits the moving particles to distinguish the functional capillaries from the stationary background. This information is used to reconstruct a map and to calculate the velocity of the moving objects.

  3. Blood clotting

    MedlinePLUS Videos and Cool Tools

    ... the external bleeding stops. Clotting factors in the blood cause strands of blood-borne material, called fibrin, to stick together and ... the inside of the wound. Eventually, the cut blood vessel heals, and the blood clot dissolves after ...

  4. Effect of rheological property on blood flow in vertebral artery branch

    NASA Astrophysics Data System (ADS)

    Min, Taegee; Kim, Myungjoon; Kim, Taesung; Kwon, O.-Ki

    2011-11-01

    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.

  5. Myeloid Lineage of Human Endothelial Outgrowth Cells Circulating in Blood and Vasculogenic Endothelial-Like Cells in the Diseased Vessel Wall

    Microsoft Academic Search

    Chunsheng Liu; Shaohua Wang; Pat Metharom; Noel M. Caplice

    2009-01-01

    Endothelial injury is a major step in the pathogenesis of atherosclerosis. Accumulated data suggest endothelial progenitor cells can derive from various sources, including the host bone marrow, circulating blood mononuclear cells, as well as resident precursors within the vessel wall. Early experimental animal data supported a haematopoietic origin for vascular precursors, but more recently cells of myeloid lineage have been

  6. Numerical Study on 3-D Light and Heat Transport in Biological Tissues Embedded with Large Blood Vessels during Laser-Induced Thermotherapy

    Microsoft Academic Search

    Jianhua Zhou; Jing Liu

    2004-01-01

    Tissue vasculature plays an important role in the temperature responses of biological bodies subject to laser heating. For example, interfaces between blood vessel and its surrounding tissues may lead to reflection or absorption of the coming laser light. However, most of the previous efforts just treat this by considering a collective model. To date, little attention has been paid to

  7. Sustained activation of c-Jun N-terminal and extracellular signal-regulated kinases in port-wine stain blood vessels

    PubMed Central

    Tan, Wenbin; Chernova, Margarita; Gao, Lin; Sun, Victor; Liu, Huaxu; Jia, Wangcun; Langer, Stephanie; Wang, Gang; Mihm, Martin C.; Nelson, J. Stuart

    2014-01-01

    Background Port-wine stain (PWS) is a congenital, progressive vascular malformation but the pathogenesis remains incompletely understood. Objective We sought to investigate the activation status of various kinases, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, AKT, phosphatidylinositol 3-kinase, P70 ribosomal S6 kinase, and phosphoinositide phospholipase C ? subunit, in PWS biopsy tissues. Methods Immunohistochemistry was performed on 19 skin biopsy samples from 11 patients with PWS. Results c-Jun N-terminal kinase, extracellular signal-regulated kinase, and P70 ribosomal S6 kinase in pediatric and adult PWS blood vessels were consecutively activated. Activation of AKT and phosphatidylinositol 3-kinase was found in many adult hypertrophic PWS blood vessels but not in infants. Phosphoinositide phospholipase C ? subunit showed strong activation in nodular PWS blood vessels. Limitation Infantile PWS sample size was small. Conclusion Our data suggest a subsequent activation profile of various kinases during different stages of PWS: (1) c-Jun N-terminal and extracellular signal-regulated kinases are firstly and consecutively activated in all PWS tissues, which may contribute to both the pathogenesis and progressive development of PWS; (2) AKT and phosphatidylinositol 3-kinase are subsequently activated, and are involved in the hypertrophic development of PWS blood vessels; and (3) phosphoinositide phospholipase C ? subunit is activated in the most advanced stage of PWS and may participate in nodular formation. PMID:25135651

  8. The role of shear forces in arterial branching

    Microsoft Academic Search

    M. Zamir

    1976-01-01

    A B S X a A C W A new optimality principle for the branching angles of blood vessels in the cardiovascular system is proposed: the principle of minimum drag. The results are examined in the light of general observations and compared with those obtained from the principles of minimum work and minimum volume. It is shown that in some

  9. Whole-Mount Confocal Microscopy for Vascular Branching Morphogenesis

    PubMed Central

    Mukouyama, Yoh-suke; James, Jennifer; Nam, Joseph; Uchida, Yutaka

    2014-01-01

    We introduce a whole-mount immunohistochemistry method for analyzing intricate vascular network formation in mouse embryonic tissues. Laser scanning confocal microscopy with multiple labeling allows for robust imaging of blood and lymphatic vessel branching morphogenesis with excellent resolution. PMID:22222522

  10. Nampt/PBEF/visfatin serum levels: a new biomarker for retinal blood vessel occlusions

    PubMed Central

    Kaja, Simon; Shah, Anna A; Haji, Shamim A; Patel, Krishna B; Naumchuk, Yuliya; Zabaneh, Alexander; Gerdes, Bryan C; Kunjukunju, Nancy; Sabates, Nelson R; Cassell, Michael A; Lord, Ron K; Pikey, Kevin P; Poulose, Abraham; Koulen, Peter

    2015-01-01

    The main objective of the study was to quantify serum levels of nicotinamide phosphoribosyltransferase (Nampt/pre-B-Cell colony-enhancing factor 1/visfatin) in subjects with a history of retinal vascular occlusions (RVOs), disease conditions characterized by pronounced ischemia, and metabolic energy deficits. A case–control study of 18 subjects with a history of RVO as well as six healthy volunteers is presented. Serum Nampt levels were quantified using a commercially available enzyme-linked immunosorbent assay kit. Serum Nampt levels were 79% lower in patients with a history of RVO compared with that in healthy volunteers (P<0.05). There was no statistically significant difference among the types of RVOs, specifically branch retinal vein occlusions (n=7), central retinal vein occlusions (n=5), hemiretinal vein occlusions (n=3), and central retinal artery occlusions (n=3; P=0.69). Further studies are needed to establish the temporal kinetics of Nampt expression and to determine whether Nampt may represent a novel biomarker to identify at-risk populations, or whether it is a druggable target with the potential to ameliorate the long-term complications associated with the condition, ie, macular edema, macular ischemia, neovascularization, and permanent loss of vision. PMID:25897200

  11. Arginase reciprocally regulates nitric oxide synthase activity and contributes to endothelial dysfunction in aging blood vessels

    NASA Technical Reports Server (NTRS)

    Berkowitz, Dan E.; White, Ron; Li, Dechun; Minhas, Khalid M.; Cernetich, Amy; Kim, Soonyul; Burke, Sean; Shoukas, Artin A.; Nyhan, Daniel; Champion, Hunter C.; Hare, Joshua M.

    2003-01-01

    BACKGROUND: Although abnormal L-arginine NO signaling contributes to endothelial dysfunction in the aging cardiovascular system, the biochemical mechanisms remain controversial. L-arginine, the NO synthase (NOS) precursor, is also a substrate for arginase. We tested the hypotheses that arginase reciprocally regulates NOS by modulating L-arginine bioavailability and that arginase is upregulated in aging vasculature, contributing to depressed endothelial function. METHODS AND RESULTS: Inhibition of arginase with (S)-(2-boronoethyl)-L-cysteine, HCl (BEC) produced vasodilation in aortic rings from young (Y) adult rats (maximum effect, 46.4+/-9.4% at 10(-5) mol/L, P<0.01). Similar vasorelaxation was elicited with the additional arginase inhibitors N-hydroxy-nor-L-arginine (nor-NOHA) and difluoromethylornithine (DFMO). This effect required intact endothelium and was prevented by 1H-oxadiazole quinoxalin-1-one (P<0.05 and P<0.001, respectively), a soluble guanylyl cyclase inhibitor. DFMO-elicited vasodilation was greater in old (O) compared with Y rat aortic rings (60+/-6% versus 39+/-6%, P<0.05). In addition, BEC restored depressed L-arginine (10(-4) mol/L)-dependent vasorelaxant responses in O rings to those of Y. Arginase activity and expression were increased in O rings, whereas NOS activity and cyclic GMP levels were decreased. BEC and DFMO suppressed arginase activity and restored NOS activity and cyclic GMP levels in O vessels to those of Y. CONCLUSIONS: These findings demonstrate that arginase modulates NOS activity, likely by regulating intracellular L-arginine availability. Arginase upregulation contributes to endothelial dysfunction of aging and may therefore be a therapeutic target.

  12. Distributing and delivering vessels of the human heart

    PubMed Central

    1988-01-01

    The branching characteristics of the right coronary artery, acute marginal, posterior descending, left anterior descending, circumflex, and obtuse marginal arteries are compared with those of diagonal branches, left and right ventricular branches, septal, and higher-order branches, to test a newly proposed functional classification of the coronary arteries in which the first group rank as distributing vessels and the second as delivering vessels. According to this classification, the function of the first type is merely to convey blood to the borders of myocardial zones, while the function of the second is to implement the actual delivery of blood into these zones. This functional difference is important in the hemodynamic analysis of coronary heart disease, as it provides an assessment of the role of a vessel within the coronary network and hence an assessment of the functional importance of that vessel in a particular heart. Measurements from casts of human coronary arteries are used to examine the relevant characteristics of these vessels and hence to test the basis of this classification. PMID:3418319

  13. Leukocyte accumulation in graft blood vessels during self-limiting acute rejection of rat kidneys.

    PubMed

    Zakrzewicz, Anna; Wilhelm, Jochen; Blöcher, Sonja; Wilczynska, Joanna; Wilker, Sigrid; Dietrich, Hartmut; Weimer, Rolf; Padberg, Winfried; Grau, Veronika

    2011-05-01

    During self-limiting acute rejection preceding chronic vasculopathy, large amounts of leukocytes, predominantly monocytes, interact with the endothelium of renal allografts. We aim to characterize them and to identify targets for functional and interventional studies. Leukocytes were harvested by vascular perfusion from Fischer 344 to Lewis renal allografts or Lewis isografts, followed by flow cytometry, quantitative RT-PCR and genome-wide transcriptional profiling. Leukocyte accumulation peaked in allografts on day 9. The percentage of monocytes expressing MHC class II and CD161 was increased whereas CD4, CD11a, CD43, and CD71 expression remained unchanged. IFN-?, IL-1?, IL-2, IL-10, TNF-?, and iNOS mRNA increased in allograft leukocytes but IL-4, IL-6, IL-12, TGF-?, and tissue factor did not. During acute rejection, 1783 genes were differentially expressed. In conclusion, graft blood leukocytes display a unique state of partial activation during self-limiting rejection. Numerous differentially expressed genes deserve further investigation as potential factors in deciding the fate of the allograft. PMID:21035231

  14. Skeletal muscle fiber, nerve, and blood vessel breakdown in space-flown rats

    NASA Technical Reports Server (NTRS)

    Riley, D. A.; Ilyina-Kakueva, E. I.; Ellis, S.; Bain, J. L.; Slocum, G. R.; Sedlak, F. R.

    1990-01-01

    Histochemical and ultrastructural analyses were performed postflight on hind limb skeletal muscles of rats orbited for 12.5 days aboard the unmanned Cosmos 1887 biosatellite and returned to Earth 2 days before sacrifice. The antigravity adductor longus (AL), soleus, and plantaris muscles atrophied more than the non-weight-bearing extensor digitorum longus, and slow muscle fibers were more atrophic than fast fibers. Muscle fiber segmental necrosis occurred selectively in the AL and soleus muscles; primarily, macrophages and neutrophils infiltrated and phagocytosed cellular debris. Granule-rich mast cells were diminished in flight AL muscles compared with controls, indicating the mast cell secretion contributed to interstitial tissue edema. Increased ubiquitination of disrupted myofibrils implicated ubiquitin in myofilament degradation. Mitochondrial content and succinic dehydrogenase activity were normal, except for subsarcolemmal decreases. Myofibrillar ATPase activity of flight AL muscle fibers shifted toward the fast type. Absence of capillaries and extravasation of red blood cells indicated failed microcirculation. Muscle fiber regeneration from activated satellite cells was detected. About 17% of the flight AL end plates exhibited total or partial denervation. Thus, skeletal muscle weakness associated with spaceflight can result from muscle fiber atrophy and segmental necrosis, partial motor denervation, and disruption of the microcirculation.

  15. Sympathetic innervation and beta-adrenoceptor profile of blood vessels in the posterior region of the rabbit knee joint.

    PubMed

    Najafipour, H; Ferrell, W R

    1993-09-01

    Experiments were performed to investigate the presence and nature of beta-adrenoceptors in blood vessels supplying the posterior capsule of the rabbit knee joint. Electrical stimulation of the posterior articular nerve (PAN) and close intra-arterial injection of adrenaline produced vasoconstriction which reversed to vasodilatation with administration of the alpha-adrenoceptor antagonist phenoxybenzamine. In almost all animals close intra-arterial injection of the beta-adrenoceptor agonist isoprenaline resulted in vasodilatation. Injection of the more selective beta-agonists dobutamine, salbutamol and terbutaline also produced vasodilatation with a rank potency order of isoprenaline > dobutamine > salbutamol > or = terbutaline. The beta-adrenoceptor antagonist propranolol abolished the dilator responses to adrenaline and isoprenaline, and significantly reduced the dilator responses to PAN stimulation in phenoxybenzamine-treated animals. Nerve-mediated vasodilatation was also reduced by the substance P antagonist D-Pro4 D-Trp7,9,10 SP4-11, suggesting that substance P contributes to this dilatation. Dobutamine, a selective beta 1-agonist, produced vasodilatation which was abolished by administration of the selective beta 1-antagonist atenolol. Isoprenaline-induced vasodilatation was substantially reduced by atenolol. The dilator response to isoprenaline appeared to be unaffected by the selective beta 2-antagonist ICI118551, but the weak dilator responses to the selective beta 2-agonists salbutamol and terbutaline were significantly reduced by this antagonist. The results of this study suggest that beta-adrenoceptors appear to be involved in the sympathetic regulation of rabbit knee joint blood flow, and that this is predominantly mediated via beta 1-adrenoceptors. PMID:7694600

  16. Distinct genetic interactions between multiple Vegf receptors are required for development of different blood vessel types in zebrafish

    PubMed Central

    Covassin, L. D.; Villefranc, J. A.; Kacergis, M. C.; Weinstein, B. M.; Lawson, N. D.

    2006-01-01

    Recent evidence indicates a specific role for vascular endothelial growth factor a (Vegfa) during artery development in both zebrafish and mouse embryos, whereas less is known about signals that govern vein formation. In zebrafish, loss of vegfa blocks segmental artery formation and reduces artery-specific gene expression, whereas veins are largely unaffected. Here, we describe a mutation in the zebrafish vegf receptor-2 homolog, kdra, which eliminates its kinase activity and leads to specific defects in artery development. We further find that Flt4, a receptor for Vegfc, cooperates with Kdr during artery morphogenesis, but not differentiation. We also identify an additional zebrafish vegfr-2 ortholog, referred to as kdrb, which can partially compensate for loss of kdra but is dispensable for vascular development in wild-type embryos. Interestingly, we find that these Vegf receptors are also required for formation of veins but in distinct genetic interactions that differ from those required for artery development. Taken together, our results indicate that formation of arteries and veins in the embryo is governed in part by different Vegf receptor combinations and suggest a genetic mechanism for generating blood vessel diversity during vertebrate development. PMID:16617120

  17. Capture of Magnetic Nanoparticles in Simulated Blood Vessels: Effects of Proteins and Coating with Poly(ethylene glycol)

    NASA Astrophysics Data System (ADS)

    Robertson, Jaimee; Brazel, Christopher

    2012-11-01

    Magnetic nanoparticles (MNPs) have applications in cancer treatment as they can be captured and localized to a diseased site by use of an external magnetic field. After localization, cancer treatments such as magnetically targeted chemotherapy and localized hyperthermia can be applied. Previously, our lab has shown that the percent capture of MNPs is significantly reduced when MNPs are dispersed in protein solutions compared to water or aqueous polymer solutions. The purpose of this study was to determine the effects of proteins on capture efficiency and to investigate the ability of poly(ethylene glycol), PEG, coatings to reduce aggregation of MNPs with proteins, allowing for a greater capture of MNPs in flow. Using Tygon® tubing to simulate blood vessels, a maghemite nanoparticle solution was pumped through a capture zone, where a magnetic field was applied. After passing through the capture zone, the fluid flowed to a spectrophotometer, which measured the absorbance of the solution. The introduction of proteins into the nanoparticle solution reduced the percent capture of MNPs. However, coating the MNPs with PEG aided in preventing aggregation and led to higher capture efficiencies in protein solutions. Additionally, the effects of capture length and protein exposure time were examined. It was found that a higher percent capture is attainable with a longer capture length. Furthermore, on a scale of hours, the percent capture is not affected by the protein exposure time. Funded by NSF REU Grant 1062611 and NIH NCI R21CA 141388.

  18. Osteoblast Precursors, but Not Mature Osteoblasts, Move into Developing and Fractured Bones along with Invading Blood Vessels

    PubMed Central

    Maes, Christa; Kobayashi, Tatsuya; Selig, Martin K.; Torrekens, Sophie; Roth, Sanford I.; Mackem, Susan; Carmeliet, Geert; Kronenberg, Henry M.

    2012-01-01

    SUMMARY During endochondral bone development, the first osteoblasts differentiate in the perichondrium surrounding avascular cartilaginous rudiments; the source of trabecular osteoblasts inside the later bone is, however, unknown. Here, we generated tamoxifen-inducible transgenic mice bred to Rosa26R-LacZ reporter mice to follow the fates of stage-selective subsets of osteoblast lineage cells. Pulse-chase studies showed that osterix-expressing osteoblast precursors, labeled in the perichondrium prior to vascular invasion of the cartilage, give rise to trabecular osteoblasts, osteocytes, and stromal cells inside the developing bone. Throughout the translocation, some precursors were found to intimately associate with invading blood vessels, in pericyte-like fashion. A similar coinvasion occurs during endochondral healing of bone fractures. In contrast, perichondrial mature osteoblasts did not exhibit perivascular localization and remained in the outer cortex of developing bones. These findings reveal the specific involvement of immature osteoblast precursors in the coupled vascular and osteogenic transformation essential to endochondral bone development and repair. PMID:20708594

  19. Hypoxia-inducible factor and vascular endothelial growth factor in the neuroretina and retinal blood vessels after retinal ischemia

    PubMed Central

    Håkansson, Gisela; Gesslein, Bodil; Gustafsson, Lotta; Englund-Johansson, Ulrica

    2010-01-01

    Retinal ischemia arises from circulatory failure. As the retinal blood vessels are key organs in circulatory failure, our aim was to study the retinal vasculature separately from the neuroretina to elucidate the role of hypoxia-inducible factor (HIF) 1? and 1? and vascular endothelial growth factor (VEGF) in retinal ischemia. Retinal ischemia was induced in porcine eyes by applying an intraocular pressure, followed by 12 h of reperfusion. HIF-1? mRNA expression was not affected by ischemia, while immunofluorescence staining was higher after ischemia in the neuroretina. HIF-1? immunoreactivity and mRNA expression were unaffected. VEGF protein levels in the vitreous humor and VEGF staining in the neuroretina were more pronounced in eyes subjected to ischemia than in the sham eyes. VEGF may be activated downstream of HIF-1 and is known to stimulate retinal neovascularization, which causes sight-threatening complications. These results emphasize the need for pharmacological treatment to block the HIF and VEGF signaling pathways in retinal ischemia. PMID:21139705

  20. A Rac/Cdc42 exchange factor complex promotes formation of lateral filopodia and blood vessel lumen morphogenesis

    PubMed Central

    Abraham, Sabu; Scarcia, Margherita; Bagshaw, Richard D.; McMahon, Kathryn; Grant, Gary; Harvey, Tracey; Yeo, Maggie; Esteves, Filomena O.G.; Thygesen, Helene H.; Jones, Pamela F.; Speirs, Valerie; Hanby, Andrew M.; Selby, Peter J.; Lorger, Mihaela; Dear, T. Neil; Pawson, Tony; Marshall, Christopher J.; Mavria, Georgia

    2015-01-01

    During angiogenesis, Rho-GTPases influence endothelial cell migration and cell–cell adhesion; however it is not known whether they control formation of vessel lumens, which are essential for blood flow. Here, using an organotypic system that recapitulates distinct stages of VEGF-dependent angiogenesis, we show that lumen formation requires early cytoskeletal remodelling and lateral cell–cell contacts, mediated through the RAC1 guanine nucleotide exchange factor (GEF) DOCK4 (dedicator of cytokinesis 4). DOCK4 signalling is necessary for lateral filopodial protrusions and tubule remodelling prior to lumen formation, whereas proximal, tip filopodia persist in the absence of DOCK4. VEGF-dependent Rac activation via DOCK4 is necessary for CDC42 activation to signal filopodia formation and depends on the activation of RHOG through the RHOG GEF, SGEF. VEGF promotes interaction of DOCK4 with the CDC42 GEF DOCK9. These studies identify a novel Rho-family GTPase activation cascade for the formation of endothelial cell filopodial protrusions necessary for tubule remodelling, thereby influencing subsequent stages of lumen morphogenesis. PMID:26129894

  1. Matrix metalloproteinase-9 mediates post-hypoxic vascular pruning of cerebral blood vessels by degrading laminin and claudin-5.

    PubMed

    Boroujerdi, Amin; Welser-Alves, Jennifer V; Milner, Richard

    2015-07-01

    Vascular remodeling involves a highly coordinated break-down and build-up of the vascular basal lamina and inter-endothelial tight junction proteins. In light of the important role of matrix metalloproteinases (MMPs) in tissue remodeling, the goal of this study was to examine the role of MMP-9 in remodeling of cerebral blood vessels, both in hypoxia-induced angiogenesis and in the vascular pruning that accompanies the switch from hypoxia back to normoxia. In a chronic mild hypoxia model of cerebrovascular remodeling, gel zymography revealed that MMP-9 levels were increased, both during hypoxic-induced angiogenesis and in the post-hypoxic pruning response. Interestingly, compared to wild-type mice, MMP-9 KO mice showed no alteration in hypoxic-induced angiogenesis, but did show marked delay in post-hypoxic vascular pruning. In wild-type mice, vascular pruning was associated with fragmentation of vascular laminin and the tight junction protein claudin-5, while this process was markedly attenuated in MMP-9 KO mice. In vitro experiments showed that hypoxia stimulated MMP-9 expression in brain endothelial cells but not pericytes. These results show that while MMP-9 is not essential for hypoxic-induced cerebral angiogenesis, it plays an important role in post-hypoxic vascular pruning by degrading laminin and claudin-5. PMID:25812799

  2. Endothelial podosome rosettes regulate vascular branching in tumour angiogenesis.

    PubMed

    Seano, Giorgio; Chiaverina, Giulia; Gagliardi, Paolo Armando; di Blasio, Laura; Puliafito, Alberto; Bouvard, Claire; Sessa, Roberto; Tarone, Guido; Sorokin, Lydia; Helley, Dominique; Jain, Rakesh K; Serini, Guido; Bussolino, Federico; Primo, Luca

    2014-10-01

    The mechanism by which angiogenic endothelial cells break the physical barrier of the vascular basement membrane and consequently sprout to form new vessels in mature tissues is unclear. Here, we show that the angiogenic endothelium is characterized by the presence of functional podosome rosettes. These extracellular-matrix-degrading and adhesive structures are precursors of de novo branching points and represent a key feature in the formation of new blood vessels. VEGF-A stimulation induces the formation of endothelial podosome rosettes by upregulating integrin ?6?1. In contrast, the binding of ?6?1 integrin to the laminin of the vascular basement membrane impairs the formation of podosome rosettes by restricting ?6?1 integrin to focal adhesions and hampering its translocation to podosomes. Using an ex vivo sprouting angiogenesis assay, transgenic and knockout mouse models and human tumour sample analysis, we provide evidence that endothelial podosome rosettes control blood vessel branching and are critical regulators of pathological angiogenesis. PMID:25218639

  3. Measurement of Retinal Blood Flow Using Fluorescently Labeled Red Blood Cells

    PubMed Central

    Kornfield, Tess E.; Newman, Eric A.

    2015-01-01

    Blood flow is a useful indicator of the metabolic state of the retina. However, accurate measurement of retinal blood flow is difficult to achieve in practice. Most existing optical techniques used for measuring blood flow require complex assumptions and calculations. We describe here a simple and direct method for calculating absolute blood flow in vessels of all sizes in the rat retina. The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs). The accuracy of the blood flow measurements was verified by (1) comparing blood flow calculated independently using either flux or velocity combined with diameter measurements, (2) measuring total retinal blood flow in arterioles and venules, (3) measuring blood flow at vessel branch points, and (4) measuring changes in blood flow in response to hyperoxic and hypercapnic challenge. Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels. We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes. PMID:26082942

  4. VEGF165 Stimulates Vessel Density and Vessel Diameter Differently in Angiogenesis and Lymphangiogenesis

    NASA Technical Reports Server (NTRS)

    Parsons-Wingerter, Patricia; Radhakrishnan, Krishnan; DiCorleto, Paul E.; Leontiev, Dmitry; Anand-Apte, Bela; Albarran, Brian; Farr, Andrew G.

    2005-01-01

    Vascular endothelial growth factor-165 (VEGF(sub 165)) stimulated angiogenesis in the quail chorioallantoic membrane (CAM) by vessel expansion from the capillary network. However, lymphangiogenesis was stimulated by the filopodial guidance of tip cells located on blind-ended lymphatic sprouts. As quantified by fractal/generational branching analysis using the computer code VESGEN, vascular density increased maximally at low VEGF concentrations, and vascular diameter increased most at high VEGF concentrations. Increased vascular density and diameter were statistically independent events (r(sub s), -0.06). By fluorescence immunohistochemistry of VEGF receptors VEGFR-1 and VEGFR-2, alpha smooth muscle actin ((alpha) SMA) and a vascular/lymphatic marker, VEGF(sub 165) increased the density and diameter of sprouting lymphatic vessels guided by tip cells (accompanied by the dissociation of lymphatics from blood vessels). Isolated migratory cells expressing (alpha)SMA were recruited to blood vessels, whereas isolated cells expressing VEGFR-2 were recruited primarily to lymphatics. In conclusion, VEGF(sub 165) increased lymphatic vessel density by lymphatic sprouting, but increased blood vessel density by vascular expansion from the capillary network.

  5. Scan-pattern and signal processing for microvasculature visualization with complex SD-OCT: tissue-motion artifacts robustness and decorrelation time - blood vessel characteristics

    NASA Astrophysics Data System (ADS)

    Matveev, Lev A.; Zaitsev, Vladimir Y.; Gelikonov, Grigory V.; Matveyev, Alexandr L.; Moiseev, Alexander A.; Ksenofontov, Sergey Y.; Gelikonov, Valentin M.; Demidov, Valentin; Vitkin, Alex

    2015-03-01

    We propose a modification of OCT scanning pattern and corresponding signal processing for 3D visualizing blood microcirculation from complex-signal B-scans. We describe the scanning pattern modifications that increase the methods' robustness to bulk tissue motion artifacts, with speed up to several cm/s. Based on these modifications, OCT-based angiography becomes more realistic under practical measurement conditions. For these scan patterns, we apply novel signal processing to separate the blood vessels with different decorrelation times, by varying of effective temporal diversity of processed signals.

  6. Blood

    MedlinePLUS

    ... a mixture of blood cells and plasma. Continue Red Blood Cells Red blood cells (RBCs, and also ... conditions involving the blood include: Diseases of the Red Blood Cells The most common condition affecting the ...

  7. E-Selectin Mediates Stem Cell Adhesion and Formation of Blood Vessels in a Murine Model of Infantile Hemangioma

    PubMed Central

    Smadja, David M.; Mulliken, John B.; Bischoff, Joyce

    2013-01-01

    Hemangioma stem cells (HemSCs) are multipotent cells isolated from infantile hemangioma (IH), which form hemangioma-like lesions when injected subcutaneously into immune-deficient mice. In this murine model, HemSCs are the primary target of corticosteroid, a mainstay therapy for problematic IH. The relationship between HemSCs and endothelial cells that reside in IH is not clearly understood. Adhesive interactions might be critical for the preferential accumulation of HemSCs and/or endothelial cells in the tumor. Therefore, we studied the interactions between HemSCs and endothelial cells (HemECs) isolated from IH surgical specimens. We found that HemECs isolated from proliferating phase IH, but not involuting phase, constitutively express E-selectin, a cell adhesion molecule not present in quiescent endothelial cells. E-selectin was further increased when HemECs were exposed to vascular endothelial growth factor–A or tumor necrosis factor–?. In vitro, HemSC migration and adhesion was enhanced by recombinant E-selectin but not P-selectin; both processes were neutralized by E-selectin–blocking antibodies. E-selectin–positive HemECs also stimulated migration and adhesion of HemSCs. In vivo, neutralizing antibodies to E-selectin strongly inhibited formation of blood vessels when HemSCs and HemECs were co-implanted in Matrigel. These data suggest that endothelial E-selectin could be a major ligand for HemSCs and thereby promote cellular interactions and vasculogenesis in IH. We propose that constitutively expressed E-selectin on endothelial cells in the proliferating phase is one mediator of the stem cell tropism in IH. PMID:23041613

  8. Vasodilatory effects of homologous adrenomedullin 2 and adrenomedullin 5 on isolated blood vessels of two species of eel.

    PubMed

    Cameron, Melissa S; Nobata, Shigenori; Takei, Yoshio; Donald, John A

    2015-01-01

    In mammals, adrenomedullin (AM) is a potent vasodilator through signalling pathways that involve the endothelium. In teleost fishes, a family of five AMs are present (AM1/4, AM2/3 and AM5) with four homologous AMs (AM1, AM2/3 and AM5) recently cloned from the Japanese eel, Anguilla japonica. Both AM2 and AM5 have been shown to be strong in vivo vasodepressors in eel, but the mechanism of action of homologous AMs on isolated blood vessels has not been examined in teleost fish. In this study, both eel AM2 and AM5 caused a marked vasodilation of the dorsal aorta. However, only AM5 consistently dilated the small gonadal artery in contrast to AM2 that had no effect in most preparations. Neither AM2 nor AM5 had any effect when applied to the first afferent branchial artery; in contrast, eel ANP always caused a large vasodilation of the branchial artery. In the dorsal aorta, indomethacin significantly reduced the AM2 vasodilation, but had no effect on the AM5 vasodilation. In contrast, removal of the endothelium significantly enhanced the AM5 vasodilation only. In the gonadal artery, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ) significantly reduced the AM5 vasodilation suggesting a role for soluble guanylyl cyclase in the dilation, but l-NNA and removal of the endothelium had no effect. The results of this study indicate that AM2 and AM5 have distinct vasodilatory effects that may be due to the peptides signalling via different receptors to regulate vascular tone in eel. PMID:25284501

  9. The absorbed dose to blood from blood-borne activity

    NASA Astrophysics Data System (ADS)

    Hänscheid, H.; Fernández, M.; Lassmann, M.

    2015-01-01

    The radiation absorbed dose to blood and organs from activity in the blood is relevant for nuclear medicine dosimetry and for research in biodosimetry. The present study provides coefficients for the average absorbed dose rates to the blood from blood-borne activity for radionuclides frequently used in targeted radiotherapy and in PET diagnostics. The results were deduced from published data for vessel radius-dependent dose rate coefficients and reasonable assumptions on the blood-volume distribution as a function of the vessel radius. Different parts of the circulatory system were analyzed separately. Vessel size information for heart chambers, aorta, vena cava, pulmonary artery, and capillaries was taken from published results of morphometric measurements. The remaining blood not contained in the mentioned vessels was assumed to reside in fractal-like vascular trees, the smallest branches of which are the arterioles or venules. The applied vessel size distribution is consistent with recommendations of the ICRP on the blood-volume distribution in the human. The resulting average absorbed dose rates to the blood per nuclear disintegration per milliliter (ml) of blood are (in 10?11?Gy·s?1·Bq?1·ml) Y-90: 5.58, I-131: 2.49, Lu-177: 1.72, Sm-153: 2.97, Tc-99m: 0.366, C-11: 4.56, F-18: 3.61, Ga-68: 5.94, I-124: 2.55. Photon radiation contributes 1.1–1.2·10?11?Gy·s?1·Bq?1·ml to the total dose rate for positron emitters but significantly less for the other nuclides. Blood self-absorption of the energy emitted by ß-particles in the whole blood ranges from 37% for Y-90 to 80% for Tc-99m. The correspondent values in vascular trees, which are important for the absorbed dose to organs, range from 30% for Y-90 to 82% for Tc-99m.

  10. Progression of carcinogen-induced fibrosarcomas is associated with the accumulation of naïve CD4+ T cells via blood vessels and lymphatics.

    PubMed

    Ondondo, Beatrice; Jones, Emma; Hindley, James; Cutting, Scott; Smart, Kathryn; Bridgeman, Hayley; Matthews, Katherine K; Ladell, Kristin; Price, David A; Jackson, David G; Godkin, Andrew; Ager, Ann; Gallimore, Awen

    2014-05-01

    The tumor microenvironment comprises newly formed blood and lymphatic vessels which shape the influx, retention and departure of lymphocytes within the tumor mass. Thus, by influencing the intratumoral composition of lymphocytes, these vessels affect the manner in which the adaptive immune system responds to the tumor, either promoting or impairing effective antitumor immunity. In our study, we utilized a mouse model of carcinogen-induced fibrosarcoma to examine the composition of tumor-infiltrating lymphocytes during tumor progression. In particular, we sought to determine whether CD4(+) Foxp3(+) regulatory T cells (Tregs) became enriched during tumor progression thereby contributing to tumor-driven immunosuppression. This was not the case as the proportion of Tregs and effector CD4(+) T cells actually declined within the tumor owing to the unexpected accumulation of naïve T cells. However, we found no evidence for antigen-driven migration of these T cells or for their participation in an antitumor immune response. Our data support the notion that lymphocytes can enter tumors via aberrantly formed blood and lymphatic vessels. Such findings suggest that targeting both the tumor vasculature and lymphatics will alter the balance of lymphocyte subpopulations that enter the tumor mass. A consideration of this aspect of tumor immunology may be critical to the success of solid cancer immunotherapies. PMID:24142504

  11. Improvements in the Quantitative Assessment of Cerebral Blood Volume and Flow with the Removal of Vessel Voxels from MR Perfusion Images

    PubMed Central

    Teng, Michael Mu Huo; Cho, I-Chieh; Kao, Yi-Hsuan; Chuang, Chi-Shuo; Chiu, Fang-Ying; Chang, Feng-Chi

    2013-01-01

    Objective. To improve the quantitative assessment of cerebral blood volume (CBV) and flow (CBF) in the brain voxels from MR perfusion images. Materials and Methods. Normal brain parenchyma was automatically segmented with the time-to-peak criteria after cerebrospinal fluid removal and preliminary vessel voxel removal. Two scaling factors were calculated by comparing the relative CBV and CBF of the segmented normal brain parenchyma with the absolute values in the literature. Using the scaling factors, the relative values were converted to the absolute CBV and CBF. Voxels with either CBV > 8?mL/100?g or CBF > 100?mL/100?g/min were characterized as vessel voxels and were excluded from the quantitative measurements. Results. The segmented brain parenchyma with normal perfusion was consistent with the angiographic findings for each patient. We confirmed the necessity of dual thresholds including CBF and CBV for proper removal of vessel voxels. The scaling factors were 0.208 ± 0.041 for CBV, and 0.168 ± 0.037, 0.172 ± 0.037 for CBF calculated using standard and circulant singular value decomposition techniques, respectively. Conclusion. The automatic scaling and vessel removal techniques provide an alternative method for obtaining improved quantitative assessment of CBV and CBF in patients with thromboembolic cerebral arterial disease. PMID:23586033

  12. Electro-acupuncture at Conception and Governor vessels and transplantation of umbilical cord blood-derived mesenchymal stem cells for treating cerebral ischemia/reperfusion injury

    PubMed Central

    Yu, Haibo; Chen, Pengdian; Yang, Zhuoxin; Luo, Wenshu; Pi, Min; Wu, Yonggang; Wang, Ling

    2014-01-01

    Mesenchymal stem cell transplantation is a novel means of treating cerebral ischemia/reperfusion, and can promote angiogenesis and neurological functional recovery. Acupuncture at Conception and Governor vessels also has positive effects as a treatment for cerebral ischemia/reperfusion. Therefore, we hypothesized that electro-acupuncture at Conception and Governor vessels plus mesenchymal stem cell transplantation may have better therapeutic effects on the promotion of angiogenesis and recovery of neurological function than either treatment alone. In the present study, human umbilical cord blood-derived mesenchymal stem cells were isolated, cultured, identified and intracranially transplanted into the striatum and subcortex of rats at 24 hours following cerebral ischemia/reperfusion. Subsequently, rats were electro-acupunctured at Conception and Governor vessels at 24 hours after transplantation. Modified neurological severity scores and immunohistochemistry findings revealed that the combined interventions of electro-acupuncture and mesenchymal stem cell transplantation clearly improved neurological impairment and up-regulated vascular endothelial growth factor expression around the ischemic focus. The combined intervention provided a better outcome than mesenchymal stem cell transplantation alone. These findings demonstrate that electro-acupuncture at Conception and Governor vessels and mesenchymal stem cell transplantation have synergetic effects on promoting neurological function recovery and angiogenesis in rats after cerebral ischemia/reperfusion. PMID:25206747

  13. Measurement of blood flow velocity in a model of stenosis in vitro and in mesenteric vessels in vivo using non-invasive micro multipoint laser Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Akiguchi, Shunsuke; Ishida, Hiroki; Andoh, Tsugunobu; Hachiga, Tadashi; Shimizu, Tadamichi; Kuraishi, Yasushi; Shirakawa, Hiroki; Ueyama, Koji

    2012-04-01

    Our research goal is to carry out two-dimensional (2D) and three-dimensional (3D) measurements of the velocity distribution within a single vessel. We modified a non-invasive beam laser Doppler velocimeter using near-infrared light, and linearized the laser to carry out simultaneous multipoint measurements. We also scanned the measurement line in the direction of depth to allow 3D imaging of vascular blood flow in opaque areas in vivo. We used micro multipoint laser Doppler velocimetry (LDV) and a device with improved spatial resolution from 250 to 125 µm. We compared actual and calculated values using a rotating disk with an attached microwire. To demonstrate the effectiveness of the proposed system, blood flowing at a constant rate through a glass capillary and the velocity distribution of flow in the capillary were measured and mapped. The average flow velocity was calculated from the cross-sectional area and flow rate in the glass capillary, and we compared the calculated and measured values. To obtain an image of blood flow velocity in vivo, we measured both 2D and 3D flow velocity distributions in mouse mesenteric vessels.

  14. Techniques of imaging of the aorta and its first order branches by endoscopic ultrasound (with videos)

    PubMed Central

    Sharma, Malay; Rai, Praveer; Mehta, Varun; Rameshbabu, C. S.

    2015-01-01

    Endoscopic ultrasonography (EUS) is a useful modality for imaging of the blood vessels of the mediastinum and abdomen. The aorta acts as an important home base during EUS imaging. The aorta and its branches are accessible by standard angiographic methods, but endosonography also provides a unique opportunity to evaluate the aorta and its branches. This article describes the techniques of imaging of different part of the aorta by EUS. PMID:26020043

  15. Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics. [for blood vessel monitoring during space flight

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Harrison, G.; Turnbill, C.; Bailey, P. F.

    1979-01-01

    Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark-adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

  16. Retinal Blood Vessel Distribution Correlates With the Peripapillary Retinal Nerve Fiber Layer Thickness Profile as Measured With GDx VCC and ECC

    PubMed Central

    Resch, Hemma; Pereira, Ivania; Weber, Stephanie; Holzer, Stephan; Fischer, Georg

    2015-01-01

    Purpose: Aim of the present study was to evaluate whether there is a correlation between retinal blood vessel density (RVD) and the peripapillary retinal nerve fiber layer (RNFL) thickness profile. Methods: RNFL thickness of 106 healthy subjects was measured using scanning laser polarimetry, GDx variable corneal compensation (VCC), and GDx enhanced corneal compensation (ECC). A proprietary software was developed in MATLAB to measure the peripapillary retinal vessels using scanning laser ophthalmoscopy fundus images, centered on the optic disc measured by Cirrus spectral domain optical coherence tomography. The individual retinal vessel positions and thickness values were integrated in a 64-sector RVD profile and intrasubject and intersubject correlations were calculated. Results: The mean R value±SD for intrasubject correlation between RVD and RNFL thickness measured with GDx VCC and GDx ECC was 0.714±0.157 and 0.629±0.140, with 105 of 106 subjects presenting significant correlations. In the intersubject linear regression analysis for GDx VCC, 33 of 64 (52%) sectors presented a significant Pearson correlation coefficient between RNFL thickness and RVD values, with a mean R value of 0.187±0.135 (P<0.05). Conclusions: Peripapillary RNFL thickness profiles correlate with the RVD over 50% of the sectors and might explain up to 26% of the interindividual variance of the peripapillary RNFL thickness values as measured with GDx VCC. To our opinion, taking into account RVD might reduce interindividual variation in peripapillary RNFL thickness profiles measured with scanning laser polarimetry. PMID:25719231

  17. Increase in choroidal blood flow in rabbits with endothelin-1 induced transient complete obstruction of retinal vessels

    Microsoft Academic Search

    Tsuyoshi Sato; Kazuo Takei; Tomohito Nonoyama; Takashi Miyauchi; Katsutoshi Goto; Sachiko Hommura

    1995-01-01

    • Background: In a previous paper, we reported that retinal blood flow (RBF) ceased immediately after injection of 1 nmol endothelin-1 (ET-1) and no recovery of RBF was detected for at least 50 min. In this study, we confirmed the same duration of RBF cessation and measured choroidal blood flow (CBF) for 180 min. • Methods: We measured CBF in

  18. GFAP-Driven GFP Expression in Activated Mouse Müller Glial Cells Aligning Retinal Blood Vessels Following Intravitreal Injection of AAV2/6 Vectors

    PubMed Central

    Pellissier, Lucie P.; Hoek, Robert M.; Vos, Rogier M.; Blits, Bas; Ehlert, Erich M. E.; Balaggan, Kamaljit S.; Ali, Robin R.; Verhaagen, Joost; Wijnholds, Jan

    2010-01-01

    Background Müller cell gliosis occurs in various retinal pathologies regardless of the underlying cellular defect. Because activated Müller glial cells span the entire retina and align areas of injury, they are ideal targets for therapeutic strategies, including gene therapy. Methodology/Principal Findings We used adeno-associated viral AAV2/6 vectors to transduce mouse retinas. The transduction pattern of AAV2/6 was investigated by studying expression of the green fluorescent protein (GFP) transgene using scanning-laser ophthalmoscopy and immuno-histochemistry. AAV2/6 vectors transduced mouse Müller glial cells aligning the retinal blood vessels. However, the transduction capacity was hindered by the inner limiting membrane (ILM) and besides Müller glial cells, several other inner retinal cell types were transduced. To obtain Müller glial cell-specific transgene expression, the cytomegalovirus (CMV) promoter was replaced by the glial fibrillary acidic protein (GFAP) promoter. Specificity and activation of the GFAP promoter was tested in a mouse model for retinal gliosis. Mice deficient for Crumbs homologue 1 (CRB1) develop gliosis after light exposure. Light exposure of Crb1?/? retinas transduced with AAV2/6-GFAP-GFP induced GFP expression restricted to activated Müller glial cells aligning retinal blood vessels. Conclusions/Significance Our experiments indicate that AAV2 vectors carrying the GFAP promoter are a promising tool for specific expression of transgenes in activated glial cells. PMID:20808778

  19. Histamine h3 and h 4 receptor ligands modify vascular histamine levels in normal and arthritic large blood vessels in vivo.

    PubMed

    Kyriakidis, Konstantinos; Zampeli, Evangelia; Palaiologou, Marina; Tiniakos, Dina; Tiligada, Ekaterini

    2015-06-01

    Growing evidence associates histamine with arthritis, but its implication in shaping vascular function in chronic inflammation remains largely elusive. This study explored the involvement of vascular histamine in the extra-articular responses in peripheral large blood vessels using a rat model of adjuvant-induced arthritis. Histamine levels were increased in the abdominal aorta and the inferior vena cava of arthritic animals. Contrary to the H1 receptor antagonist dimetindene, histamine induction was observed following administration of the H3 and H4 receptor ligands GSK334429 and JNJ7777120, respectively. In arthritis, prophylactic treatment with GSK334429 partially attenuated the clinical signs and restored basal histamine levels only in the abdominal aorta. This study is the first to implicate the H3 and H4 receptors in a concerted constitutive regulation of basal vascular histamine in the rat large blood vessels and to identify the H3 receptor as a component that may influence arterial histamine during the onset of arthritis. PMID:25359709

  20. Evaluation of doxorubicin-loaded pH-sensitive polymeric micelle release from tumor blood vessels and anticancer efficacy using a dorsal skin-fold window chamber model

    PubMed Central

    Jin, Zhe-hu; Jin, Ming-ji; Jiang, Chang-gao; Yin, Xue-zhe; Jin, Shuai-xing; Quan, Xiu-quan; Gao, Zhong-gao

    2014-01-01

    Aim: To evaluation the doxorubicin (DOX)-loaded pH-sensitive polymeric micelle release from tumor blood vessels into tumor interstitium using an animal vessel visibility model, the so-called dorsal skin-fold window chamber model. Methods: DOX-loaded pH-sensitive polyHis-b-PEG micelles and DOX-loaded pH-insensitive PLLA-b-PEG micelles were prepared. The uptake of the micelles by MDA-MB-231 breast cancer cells in vitro and in vivo was examined using flow cytometry. The pharmacokinetic parameters of the micelles were determined in SD rats after intravenous injection of a DOX dose (6 mg/kg). The release of the micelles from tumor vasculature and the antitumor efficacy were evaluated in MDA-MB-231 breast cancer xenografted in nude mice using a dorsal skin-fold window chamber. Results: The effective elimination half-life t1/2 of the pH-sensitive, pH-insensitive polymeric micelles and DOX-PBS in rats were 11.3 h, 9.4 h, and 2.1 h, respectively. Intravital microscopy in MDA-MB-231 breast cancer xenografted in nude mice showed that the pH-sensitive polymeric micelles rapidly extravasated from the tumor blood vessels, and DOX carried by the pH-sensitive micelles was preferentially released at the tumor site as compared to the pH-insensitive polymeric micelles. Furthermore, the pH-sensitive polymeric micelles exhibited significant greater efficacy in inhibition of tumor growth in the nude mice. Conclusion: When DOX is loaded into pH-sensitive polymeric micelles, the acidity in tumor interstitium causes the destabilization of the micelles and triggers drug release, resulting in high local concentrations within the tumor, thus more effectively inhibiting the tumor growth in vivo. PMID:24902790

  1. 46 CFR 169.733 - Fire extinguishing branch lines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Fire extinguishing branch...SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.733 Fire extinguishing branch...line valve of every fire extinguishing system must be plainly...

  2. Freezing by a flat, circular surface cryoprobe of a tissue phantom with an embedded cylindrical heat source simulating a blood vessel.

    PubMed

    Massalha, Loay; Shitzer, Avraham

    2004-12-01

    The effects of a thermally-significant blood vessel, simulated by an embedded acrylic tube, 4.8 mm outer diameter on the freezing field caused by a surface cryoprobe were studied experimentally in a tissue phantom. The flat, 15 mm diameter, circular cryoprobe was operated at a constant cooling rate of -8 degrees C/min by liquid nitrogen down to -60 degrees C. Water flow rates of 30 and 100 ml/min, at a constant temperature of 32.5 degrees C, were maintained in the embedded tube. The latter flow rate is typical to the lower range of blood flows in large arteries in the human body. The phase changing medium (PCM) used was a 30/70% by volume mashed potatoes flakes-water solution. Temperature measurements inside the PCM were performed in one plane perpendicular to the embedded tube, relative to which the cryoprobe was placed at 5 locations in separate experiments. This novel experimental method reduced the perturbation caused by the thermocouple junctions while facilitating rather detailed measurements of the temperature fields developing in the PCM. Results show the development of two hump-like formations on either side of the embedded tube. Freezing was retarded in the region away from the surface cryoprobe and under the tube. This accentuated the dominance of the axial effects, due to the embedded tube, over the radial ones due to the cryoprobe. Results of this study should be considered in designing protocols of cryosurgical procedures performed in the vicinity of thermally-significant blood vessels. PMID:15796332

  3. Effect of Recombinant Human Epidermal Growth Factor Impregnated Chitosan Film on Hemostasis and Healing of Blood Vessels

    PubMed Central

    Lee, Sangshin; Jung, Inwook; Yu, Seongcheol

    2014-01-01

    Background Bleeding can be a problem in wound debridement. In search for an effective hemostatic agent, we experimented with a chitosan film combined with the recombinant human epidermal growth factor (rh-EGF), hypothesizing that it would achieve effective hemostasis and simultaneously enhance arterial healing. Methods Forty-eight Sprague-Dawley rats were used, and 96 puncture wounds were made. The wounds were divided into the following four groups: treated with sterile gauze, treated with gelatin sponge, treated with chitosan, and treated with chitosan combined with rh-EGF. Immediate hemostasis was evaluated, and arterial healing was observed histologically. Results Groups B, C, and D showed a significant rate of immediate hemostasis as compared to group A (P<0.05), but there were no significant differences among groups B, C, and D. Histologically, only group D showed good continuity of the vessel wall after 1 week. It was the only group to show smooth muscle cell nuclei of the vessel wall. Conclusions We observed that chitosan has an effective hemostatic potential and the mix of rh-EGF and chitosan does not interfere with chitosan's hemostatic capabilities. We also identified enhanced healing of vessel walls when rh-EGF was added to chitosan. Further research based on these positive findings is needed to evaluate the potential use of this combination on difficult wounds like chronic diabetic ulcerations. PMID:25276636

  4. A real-time technique for improving molecular imaging and guiding drug delivery in large blood vessels: in vitro and ex vivo results

    PubMed Central

    Patil, Abhay V.; Rychak, Joshua J.; Klibanov, Alexander L.; Hossack, John A.

    2010-01-01

    Ultrasound-based molecular imaging employs targeted microbubbles to image vascular pathology. This approach also has the potential to monitor molecularly targeted microbubble-based drug-delivery. We present an image-guided drug-delivery technique that uses multiple pulses to translate, image and cavitate microbubbles in real-time. This technique can be applied to both imaging of pathology in large arteries (sizes and flow comparable to those in humans), and guiding localized drug delivery in blood vessels. The microbubble translation (or pushing) efficacy of this technique was compared in a variety of flow media: saline, viscous saline (4 cp) and bovine blood. It was observed that the performance of this approach was marginally better (by 6, 4 and 2 dB) in viscous saline than in bovine blood with varying levels of hematocrit (40%, 30% and 10%). The drug delivery efficacy of this technique was evaluated by in vitro and ex vivo experiments. High-intensity pulses mediated fluorophore (DiI) deposition on endothelial cells (in vitro) without causing cell destruction. Ex vivo fluorophore-delivery experiments conducted on swine carotids of 2 and 5 mm cross-section diameter demonstrated a high degree of correspondence in spatial localization of the fluorophore-delivery between the ultrasound and composite fluorescence-microscopy images of the arterial cross-sections. PMID:21521555

  5. Pharmacological characterization of receptor types mediating the dilator action of anandamide on blood vessels of the rat knee joint

    Microsoft Academic Search

    Francis F. Y. Lam; Phoebe W. S. Luk; Ethel S. K. Ng

    2007-01-01

    This study investigates the actions of N-(2-hydroxyethyl)-5Z,8Z,11Z,14Z-eicosatetraenamide (anandamide) on blood flow of the rat knee joint. Topical bolus administration of anandamide (10–1000 nmol) onto the exposed knee joint capsules produced dose-dependent increases in the knee joint blood flow. Various antagonists were tested on the vasodilator response to 100 nmol anandamide. Capsazepine (N-[2-(4-chlorophenyl)ethyl]-1,3,4,5-tetrahydro-7,8-dihydroxy-2H-2-benzazepine-2-carbothioamide), an antagonist of the transient receptor potential vanilloid type 1

  6. Disruption of the subendothelial basement membrane during neutrophil diapedesis in an in vitro construct of a blood vessel wall.

    PubMed Central

    Huber, A R; Weiss, S J

    1989-01-01

    To examine the course of physiologic interactions between extravasating neutrophils and the subendothelial basement membrane, a model of the venular vessel wall was constructed by culturing human umbilical vein endothelial cells on a collagen matrix. After 21 d in culture, the endothelial cell monolayer displayed in vivo-like intercellular borders and junctions, deposited a single-layered, continuous basement membrane that was impenetrable to colloidal particles, and supported neutrophil extravasation in a physiologic manner. Using this model, we demonstrate that neutrophil transmigration in a plasma milieu was associated with a significant disruption of the retentive properties of the basement membrane in the absence of discernable morphologic changes. The loss of basement membrane integrity associated with neutrophil diapedesis was not dependent on neutrophil elastase or cathepsin G and was resistant to inhibitors directed against neutrophil collagenase, gelatinase, and heparanase. Despite the fact that this loss in matrix integrity could not be prevented, basement membrane defects were only transiently expressed before they were repaired by the overlying endothelium via a mechanism that required active protein and RNA synthesis. These data indicate that neutrophil extravasation and reversible basement membrane disruption are coordinated events that occur as a consequence of vessel wall transmigration. Images PMID:2703527

  7. Direct observation of liposome uptake by leukocytes in vivo in skin blood vessels using intravital fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Devoisselle, Jean-Marie; Mordon, Serge R.; Begu, Sylvie; Desmettre, Thomas

    2000-04-01

    This study aimed to observe liposome uptake by leukocytes in vivo. The study was performed on skin by using a dorsal skin-fold chamber implanted in golden hamsters using intravital microscopy. 5,6-CF-encapsulated PEGylated liposomes were injected intravenously. The skin microcirculation was observed with an intravital Eclipse E800 Nikon microscope fitted with a Xenon light source and an epi-fluorescence assembly. An ultra-high sensitivity video-camera mounted on the microscope projected the image onto a monitor, and the images were recorded for playback analysis with a digital video cassette recorder. An acute inflammatory response was obtained by removing one complete layer of skin and the underlying fascia and avascular tissue on the opposing side of the flap corresponding to an area equivalent to the window aperture. Using these model and set-up, leukocyte rolling and adhesion were easily observed and the entry of PEGylated liposomes into hamster blood leukocytes was studied for a period of 6 hours. PEGylated liposomes were clearly identified alone inside the blood flow and inside the leukocytes as soon as the inflammatory reaction appeared. This study shows for the first time that blood leukocytes in their natural milieu of whole blood are capable of interacting with, and taking up liposomes. This observation is in accordance with previous in vitro studies.

  8. Effects of nerve growth factor (NGF) on blood vessels area and expression of the angiogenic factors VEGF and TGFbeta1 in the rat ovary

    PubMed Central

    Julio-Pieper, Marcela; Lara, Hernán E; Bravo, Javier A; Romero, Carmen

    2006-01-01

    Background Angiogenesis is a crucial process in follicular development and luteogenesis. The nerve growth factor (NGF) promotes angiogenesis in various tissues. An impaired production of this neurotrophin has been associated with delayed wound healing. A variety of ovarian functions are regulated by NGF, but its effects on ovarian angiogenesis remain unknown. The aim of this study was to elucidate if NGF modulates 1) the amount of follicular blood vessels and 2) ovarian expression of two angiogenic factors: vascular endothelial growth factor (VEGF) and transforming growth factor beta 1 (TGFbeta1), in the rat ovary. Results In cultured neonatal rat ovaries, NGF increased VEGF mRNA and protein levels, whereas TGFbeta1 expression did not change. Sectioning of the superior ovarian nerve, which increases ovarian NGF protein content, augmented VEGF immunoreactivity and the area of capillary vessels in ovaries of prepubertal rats compared to control ovaries. Conclusion Results indicate that NGF may be important in the maintenance of the follicular and luteal vasculature in adult rodents, either indirectly, by increasing the expression of VEGF in the ovary, or directly via promoting the proliferation of vascular cells. This data suggests that a disruption on NGF regulation could be a component in ovarian disorders related with impaired angiogenesis. PMID:17096853

  9. Computer simulation of MHD blood conveying gold nanoparticles as a third grade non-Newtonian nanofluid in a hollow porous vessel.

    PubMed

    Hatami, M; Hatami, J; Ganji, D D

    2014-02-01

    In this paper, heat transfer and flow analysis for a non-Newtonian third grade nanofluid flow in porous medium of a hollow vessel in presence of magnetic field are simulated analytically and numerically. Blood is considered as the base third grade non-Newtonian fluid and gold (Au) as nanoparticles are added to it. The viscosity of nanofluid is considered a function of temperature as Vogel's model. Least Square Method (LSM), Galerkin method (GM) and fourth-order Runge-Kutta numerical method (NUM) are used to solve the present problem. The influences of the some physical parameters such as Brownian motion and thermophoresis parameters on non-dimensional velocity and temperature profiles are considered. The results show that increasing the thermophoresis parameter (N(t)) caused an increase in temperature values in whole domain and an increase in nanoparticles concentration just near the inner wall of vessel. Furthermore by increasing the MHD parameter, velocity profiles decreased due to magnetic field effect. PMID:24286727

  10. Increased bilateral expression of ?1-adrenoceptors on peripheral nerves, blood vessels and keratinocytes does not account for pain or neuroinflammatory changes after distal tibia fracture in rats.

    PubMed

    Drummond, E S; Dawson, L F; Finch, P M; Li, W; Guo, T-Z; Kingery, W S; Drummond, P D

    2014-10-01

    In certain forms of nerve injury and inflammation, noradrenaline augments pain via actions on up-regulated ?1-adrenoceptors (?1-ARs). The aim of this study was to use immunohistochemistry to examine ?1-AR expression on peripheral neurons, cutaneous blood vessels and keratinocytes after distal tibia fracture and cast immobilization, a model of complex regional pain syndrome type 1. We hypothesized that there would be increased ?1-AR expression on neurons and keratinocytes in the injured limb in comparison to the contralateral unaffected limb after distal tibia fracture, in association with inflammatory changes and pain. ?1-AR expression was increased on plantar keratinocytes, dermal blood vessels and peripheral nerve fibers at 16weeks after injury both in the fractured and contralateral uninjured limb. Similar changes were seen in controls whose limb had been immobilized in a cast for 4weeks but not fractured. Neurofilament 200 (NF200), a marker of myelinated neurons, and calcitonin gene-related peptide (CGRP), a neuropeptide involved in neuro-inflammatory signaling, decreased 4weeks after fracture and casting but then increased at the 16-week time point. As some of these changes were also detected in the contralateral hind limb, they probably were triggered by a systemic response to fracture and casting. Soon after the cast was removed, intraplantar injections of the ?1-AR antagonist prazosin released local vasoconstrictor tone but had no effect on pain behaviors. However, systemic injection of prazosin inhibited behavioral signs of pain, suggesting that fracture and/or casting triggered an up-regulation of ?1-ARs in central nociceptive pathways that augmented pain. Together, these findings indicate that ?1-AR expression increases in the hind limbs after distal tibia fracture and cast immobilization. However, these peripheral increases do not contribute directly to residual pain. PMID:25267387

  11. Numerical Study on Flows of Red Blood Cells with Liposome-Encapsulated Hemoglobin at Microvascular Bifurcation

    NASA Astrophysics Data System (ADS)

    Hyakutake, Toru; Tani, Shigeki; Matsumoto, Takeshi; Yanase, Shinichiro

    2008-11-01

    Flow analysis at microvascular bifurcation after partial replacement of red blood cell (RBC) with liposome-encapsulated hemoglobin (LEH) was performed using the lattice Boltzmann method. A two-dimensional bifurcation model with a parent vessel and daughter branch was considered, and the distributions of the RBC, LEH, and oxygen fluxes were calculated. When only RBCs flow into the daughter branches with unevenly distributed flows, plasma separation occurred and the RBC flow to the lower-flow branch was disproportionately decreased. On the other hand, when the half of RBC are replaced by LEH, the biasing of RBC flow was enhanced whereas LEH flowed favorably into the lower-flow branch, because many LEH within the parent vessel are suspended in the plasma layer, where no RBCs exist. Consequently, the branched oxygen fluxes became nearly proportional to flows. These results indicate that LEH facilitates oxygen supply to branches that are inaccessible to RBCs.

  12. Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution

    PubMed Central

    Qiu, Penghe; Mao, Chuanbin

    2010-01-01

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. Based on this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fibers. First, inorganic material such as silica with high affinity against the PVP could be deposited on the surface of the branched hollow PVP fibers to form branched hollow silica fibers. To extend the application of PVP self-assembly in templating the formation of hollow branched fibers, we then adopted a second approach where the PVP molecules bound to inorganic nanoparticles (using gold nanoparticles as a model) co-self-assemble with the free PVP molecules in an aqueous solution, resulting in the formation of the branched hollow fibers with the nanoparticles embedded in the PVP matrix constituting the walls of the fibers. Heating the resultant fibers above the glass transition temperature of PVP led to the formation of branched hollow gold fibers. Our work suggests that the self-assembly of the PVP molecules in the solution can serve as a general method for directing the formation of branched hollow inorganic fibers. The branched hollow fibers may find potential applications in microfluidics, artificial blood vessel generation, and tissue engineering. PMID:20158250

  13. Identification of pro-angiogenic markers in blood vessels from stroked-affected brain tissue using laser-capture microdissection

    PubMed Central

    Slevin, Mark; Krupinski, Jerzy; Rovira, Norma; Turu, Marta; Luque, Ana; Baldellou, Maribel; Sanfeliu, Coral; de Vera, Nuria; Badimon, Lina

    2009-01-01

    Background Angiogenesis correlates with patient survival following acute ischaemic stroke, and survival of neurons is greatest in tissue undergoing angiogenesis. Angiogenesis is critical for the development of new microvessels and leads to re-formation of collateral circulation, reperfusion, enhanced neuronal survival and improved recovery. Results Here, we have isolated active (CD105/Flt-1 positive) and inactive (CD105/Flt-1 minus (n=5) micro-vessel rich-regions from stroke-affected and contralateral tissue of patients using laser-capture micro-dissection. Areas were compared for pro- and anti-angiogenic gene expression using targeted TaqMan microfluidity cards containing 46 genes and real-time PCR. Further analysis of key gene de-regulation was performed by immunohistochemistry to define localization and expression patterns of identified markers and de novo synthesis by human brain microvessel endothelial cells (HBMEC) was examined following oxygen-glucose deprivation (OGD). Our data revealed that seven pro-angiogenic genes were notably up-regulated in CD105 positive microvessel rich regions. These were, beta-catenin, neural cell adhesion molecule (NRCAM), matrix metalloproteinase-2 (MMP-2), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), hepatocyte growth factor-alpha (HGF-alpha), monocyte chemottractant protein-1 (MCP-1) and and Tie-2 as well as c-kit. Immunohistochemistry demonstrated strong staining of MMP-2, HGF-alpha, MCP-1 and Tie-2 in stroke-associated regions of active remodeling in association with CD105 positive staining. In vitro, OGD stimulated production of Tie-2, MCP-1 and MMP-2 in HBMEC, demonstrated a de novo response to hypoxia. Conclusion In this work we have identified concurrent activation of key angiogenic molecules associated with endothelial cell migration, differentiation and tube-formation, vessel stabilization and stem cell homing mechanisms in areas of revascularization. Therapeutic stimulation of these processes in all areas of damaged tissue might improve morbidity and mortality from stroke. PMID:19292924

  14. Validation of an open source framework for the simulation of blood flow in rigid and deformable vessels.

    PubMed

    Passerini, T; Quaini, A; Villa, U; Veneziani, A; Canic, S

    2013-11-01

    We discuss in this paper the validation of an open source framework for the solution of problems arising in hemodynamics. The proposed framework is assessed through experimental data for fluid flow in an idealized medical device with rigid boundaries and a numerical benchmark for flow in compliant vessels. The core of the framework is an open source parallel finite element library that features several algorithms to solve both fluid and fluid-structure interaction problems. The numerical results for the flow in the idealized medical device (consisting of a conical convergent, a narrow throat, and a sudden expansion) are in good quantitative agreement with the measured axial components of the velocity and pressures for three different flow rates corresponding to laminar, transitional, and turbulent regimes. We emphasize the crucial role played by the accuracy in performing numerical integration, mesh, and time step to match the measurements. The numerical fluid-structure interaction benchmark deals with the propagation of a pressure wave in a fluid-filled elastic tube. The computed pressure wave speed and frequency of oscillations, and the axial velocity of the fluid on the tube axis are close to the values predicted by the analytical solution associated with the benchmark. A detailed account of the methods used for both benchmarks is provided. PMID:23798339

  15. Four-wavelength retinal vessel oximetry

    Microsoft Academic Search

    Jonathan Jensen Drewes

    1999-01-01

    This dissertation documents the design and construction of a four-wavelength retinal vessel oximeter, the Eye Oximeter (EOX). The EOX scans low-powered laser beams (at 629, 678, 821 and 899 nm) into the eye and across a targeted retinal vessel to measure the transmittance of the blood within the vessel. From the transmittance measurements, the oxygen saturation of the blood within

  16. Image-based computational fluid dynamics in blood vessel models: toward developing a prognostic tool to assess cardiovascular function changes in prolonged space flights

    NASA Astrophysics Data System (ADS)

    Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

    2005-04-01

    One of NASA"s objectives is to be able to perform a complete pre-flight evaluation of possible cardiovascular changes in astronauts scheduled for prolonged space missions. Blood flow is an important component of cardiovascular function. Lately, attention has focused on using computational fluid dynamics (CFD) to analyze flow with realistic vessel geometries. MRI can provide detailed geometrical information and is the only clinical technique to measure all three spatial velocity components. The objective of this study was to investigate the reliability of MRI-based model reconstruction for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction using different resolution settings. The vessel walls were identified and the geometry was reconstructed using existing software. The geometry was then imported into a commercial CFD package for meshing and numerical solution. MRI velocity acquisitions provided true inlet boundary conditions for steady flow, as well as three-directional velocity data at several locations. In addition, an idealized version of each geometry was created from the model drawings. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with mean differences <10%. CFD results from different MRI resolution settings did not show significant differences (<5%). This study showed quantitatively that reliable CFD simulations can be performed in models reconstructed from MRI acquisitions and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system is possible.

  17. A multicomponent bioactive tissue-engineered blood vessel: Fabrication, mechanical evaluation and biological evaluation with physiological-relevant conditions

    NASA Astrophysics Data System (ADS)

    Bonani, Walter

    The high long-term failure rate of synthetic vascular grafts in the replacement of small vessels is known to be associated with the lack of physiological signals to vascular cells causing adverse hemodynamic, inflammatory or coagulatory events. Current studies focus on developing engineered vascular devices with ability of directing cell activity in vitro and in vivo for tissue regeneration. It is also known that controlled molecule release from scaffolds can dramatically increase the scaffold ability of directing cell activities in vitro and in vivo for tissue regeneration. To address the mechanical and biological problems associated with graft materials, we demonstrated a degradable polyester-fibroin composite tubular scaffolds which shows well-integrated nanofibrous structure, endothelial-conducive surface and anisotropic mechanical property, suitable as engineered vascular constructs. Tissue regeneration needs not only functional biomolecules providing signaling cues to cells and guide tissue remodeling, but also an adequate modality of molecule delivery. In fact, healthy tissue formation requires specific signals at well-defined place and time. To develop scaffolds with multi-modal presentation of biomolecules, we patterned electrospun nanofibers over the thickness of the 3-dimensional scaffolds by programming the deposition of interpenetrating networks of degradable polymers poly(a-caprolactone) and poly(lactide-co-glycolide) acid in tailored proportion. Fluorescent model molecules, drug and growth factors were embedded in the polymeric fibers with different techniques and release profiles were obtained and discussed. Fabrication process resulted in precise gradient patterns of materials and functional biomolecules throughout the thickness of the scaffold. These graded materials showed programmable spatio-temporal control over the release. Molecule release profiles on each side of the scaffolds were used to determine the separation efficiency of molecule delivery, which achieved >90% for proteins in 200microm scaffolds. Gradient-patterned scaffolds were also used to program simultaneous release of two proteins to the opposite sides of the scaffold and sequential release of proteins to a defined space, which further demonstrate the ability of patterned nanofibers to spatially and temporally confine sustained release. Moreover, results showed that temporal release kinetics could be altered by the structural patterns. Thus, the hierarchically-structured scaffolds presented here may enable development of novel multifunctional scaffolds with defined 3D dynamic microenvironments for tissue regeneration.

  18. Blood vessel hyperpermeability and pathophysiology in human tumour xenograft models of breast cancer: a comparison of ectopic and orthotopic tumours

    PubMed Central

    2012-01-01

    Background Human tumour xenografts in immune compromised mice are widely used as cancer models because they are easy to reproduce and simple to use in a variety of pre-clinical assessments. Developments in nanomedicine have led to the use of tumour xenografts in testing nanoscale delivery devices, such as nanoparticles and polymer-drug conjugates, for targeting and efficacy via the enhanced permeability and retention (EPR) effect. For these results to be meaningful, the hyperpermeable vasculature and reduced lymphatic drainage associated with tumour pathophysiology must be replicated in the model. In pre-clinical breast cancer xenograft models, cells are commonly introduced via injection either orthotopically (mammary fat pad, MFP) or ectopically (subcutaneous, SC), and the organ environment experienced by the tumour cells has been shown to influence their behaviour. Methods To evaluate xenograft models of breast cancer in the context of EPR, both orthotopic MFP and ectopic SC injections of MDA-MB-231-H2N cells were given to NOD scid gamma (NSG) mice. Animals with matched tumours in two size categories were tested by injection of a high molecular weight dextran as a model nanocarrier. Tumours were collected and sectioned to assess dextran accumulation compared to liver tissue as a positive control. To understand the cellular basis of these observations, tumour sections were also immunostained for endothelial cells, basement membranes, pericytes, and lymphatic vessels. Results SC tumours required longer development times to become size matched to MFP tumours, and also presented wide size variability and ulcerated skin lesions 6 weeks after cell injection. The 3 week MFP tumour model demonstrated greater dextran accumulation than the size matched 5 week SC tumour model (for P?

  19. Localized Dose Enhancement to Tumor Blood Vessel Endothelial Cells via Megavoltage X-rays and Targeted Gold Nanoparticles: New Potential for External Beam Radiotherapy

    SciTech Connect

    Berbeco, Ross I., E-mail: rberbeco@partners.org [Department of Radiation Oncology, Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Ngwa, Wilfred; Makrigiorgos, G. Mike [Department of Radiation Oncology, Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States)

    2011-09-01

    Purpose: Tumor endothelial cell damage during radiation therapy may contribute significantly to tumor eradication and treatment efficacy. Gold nanoparticles (AuNPs) delivered preferentially to the walls of tumor blood vessels produce low-energy, short-range photoelectrons during external beam radiotherapy, boosting dose to the tumor microvasculature. In this study dosimetry at the single-cell level is used to estimate the anticipated AuNP-mediated dose enhancement to tumor endothelial cells during 6-MV X-ray irradiation. Methods and Materials: Endothelial cells are modeled as thin slabs with 100-nm-diameter AuNPs attached within the blood vessel. The number of photoelectrons emitted per AuNP per gray of X-rays is computed at multiple points along the external beam central axis by use of a Monte Carlo-generated energy fluence spectrum. The energy deposited from AuNP emissions to the endothelium is calculated based on an analytic method incorporating the energy-loss formula of Cole. The endothelial dose enhancement factor (EDEF) is the ratio of the overall (externally plus internally generated) dose to endothelial cells in the presence of AuNPs to the dose without AuNPs (from the external beam only). Results: At 20-cm depth, the EDEF is 1.7 (70% dose increase) for an intravascular AuNP concentration of 30 mg/g. Most of this dose enhancement arises from the low-energy (approximately 100 keV) portion of the linear accelerator X-ray spectrum. Furthermore, for AuNP concentrations ranging from 7 to 140 mg/g, EDEF values of 1.2 to 4.4 (20-340% dose increase) are calculated. Conclusions: In contrast to calculations assuming that AuNPs distributed homogeneously throughout the target volume (macrodosimetry), our cellular microdosimetry calculations predict a major dose enhancement to tumor microvasculature from conventional linear accelerator X-rays. This effect may enable the delivery of ablative therapeutic doses to these sensitive microstructures while maintaining established dose constraints for the organs at risk.

  20. Blood Pressure Medicines

    MedlinePLUS

    ... reducing sodium in your diet, you may need medicines. Blood pressure medicines work in different ways to lower blood pressure. ... and widen blood vessels. Often, two or more medicines work better than one. NIH: National Heart, Lung, ...

  1. A novel bispecific immunotoxin delivered by human bone marrow-derived mesenchymal stem cells to target blood vessels and vasculogenic mimicry of malignant gliomas

    PubMed Central

    Zhang, Yonghong; Sun, Xinlin; Huang, Min; Ke, Yiquan; Wang, Jihui; Liu, Xiao

    2015-01-01

    Background In previous years, immunotoxins have been shown to be a greatly promising therapeutic tool for brain malignancies, such as gliomas. Human mesenchymal stem cells (hMSCs) exhibit tropism to tumor tissue. However, the effect of bispecific immunotoxins in malignant gliomas is still unknown. The aim of this study was to investigate the function of bispecific immunotoxins in human malignant gliomas. Materials and methods In the present study, the bispecific immunotoxin VEGF165-ephrin A1-PE38KDEL was established using deoxyribonucleic acid shuffling and cloning techniques. The VEGF165-ephrin A1-PE38KDEL was delivered by hMSCs to mouse malignant gliomas. The effects of the bispecific immunotoxins on glioma-derived blood vessels and vasculogenic mimicry to elucidate the molecular mechanisms underlying the antitumorigenic effects of immunotoxins were examined in vivo. Results In vitro, transfected hMSCs significantly inhibited the cell viability of gliomas cell lines U87 and U251 in a dose-dependent manner compared with untransfected hMSCs (P<0.01). In vivo, the intratumoral injection of engineered hMSCs was effective at inhibiting tumor growth in a malignant glioma tumor model. Conclusion The bispecific immunotoxin secreted from hMSCs acts as a novel strategy for improving treatment options for malignant gliomas in the clinic.

  2. VEGFR-3 controls tip to stalk conversion at vessel fusion sites by reinforcing Notch signalling

    Microsoft Academic Search

    Tuomas Tammela; Georgia Zarkada; Harri Nurmi; Krista Heinolainen; Denis Tvorogov; Wei Zheng; Claudio A. Franco; Aino Murtomäki; Evelyn Aranda; Naoyuki Miura; Seppo Ylä-Herttuala; Marcus Fruttiger; Anne Eichmann; Jeffrey W. Pollard; Holger Gerhardt; Lars Jakobsson; Taija Mäkinen; Kari Alitalo

    2011-01-01

    Angiogenesis, the growth of new blood vessels, involves specification of endothelial cells to tip cells and stalk cells, which is controlled by Notch signalling, whereas vascular endothelial growth factor receptor (VEGFR)-2 and VEGFR-3 have been implicated in angiogenic sprouting. Surprisingly, we found that endothelial deletion of Vegfr3, but not VEGFR-3-blocking antibodies, postnatally led to excessive angiogenic sprouting and branching, and

  3. Three-dimensional Flow-Independent Balanced Steady-State Free Precession Vessel Wall MRI of the Popliteal Artery: Preliminary Experience and Comparison with Flow-Dependent Black Blood Techniques

    PubMed Central

    Kawaji, Keigo; Nguyen, Thanh D.; Zou, Zhitong; Reig, Beatriu; Winchester, Priscilla A.; Shih, Andrew; Spincemaille, Pascal; Prince, Martin R.; Wang, Yi

    2011-01-01

    Purpose To examine the feasibility of flow-independent T2-prepared inversion recovery (T2IR) black blood (BB) magnetization preparation for 3D balanced steady-state free precession (SSFP) vessel wall MRI of the popliteal artery, and to evaluate its performance relative to flow-dependent double inversion recovery (DIR), spatial presaturation (SPSAT) and motion-sensitizing magnetization preparation (MSPREP) BB techniques in healthy volunteers. Materials and Methods Eleven subjects underwent 3D MRI at 1.5T with four techniques performed in a randomized order. Wall and lumen signal-to-noise ratio (SNR), wall-to-lumen contrast-to-noise ratio (CNR), vessel wall area and lumen area were measured at proximal, middle and distal locations of the imaged popliteal artery. Image quality scores based on wall visualization and degree of intraluminal artifacts were also obtained. Results In the proximal region, DIR and SPSAT had higher wall SNR and wall-to-lumen CNR than both MSPREP and T2IR. In the middle and distal regions, DIR and SPSAT failed to provide effective blood suppression, while MSPREP and T2IR provided adequate black blood contrast with comparable wall-to-lumen CNR and image quality. Conclusion The feasibility of 3D SSFP imaging of the popliteal vessel wall using flow-independent T2IR was demonstrated with effective blood suppression and good vessel wall visualization. Although DIR and SPSAT are effective for thin slab imaging, MSPREP and T2IR are better suited for 3D thick slab imaging. PMID:21769963

  4. Dual-modal upconversion fluorescent/X-ray imaging using ligand-free hexagonal phase NaLuF4:Gd/Yb/Er nanorods for blood vessel visualization.

    PubMed

    Zeng, Songjun; Wang, Haibo; Lu, Wei; Yi, Zhigao; Rao, Ling; Liu, Hongrong; Hao, Jianhua

    2014-03-01

    Visualization of blood vessel of lung can improve the detection of the lung and pulmonary vascular diseases. However, research on visualization of blood vessel of lung using the new generation upconversion nanoprobes is still scarce. Herein, high quality hexagonal phase NaLuF4:Gd/Yb/Er nanorods were synthesized by a simple hydrothermal method through doping Gd(3+). Doping Gd can not only promote the phase transformation from cubic to hexagonal and the shape evolution from microtube to rod-like, but also provide an additional magnetic properties for biomedical application. The as-prepared nanorods were further converted to water solubility by treating with HCl for eliminating the capped oleic acid. The ligand-free nanorods were successfully used for high-contrast upconversion fluorescent bioimaging of HeLa cells. Moreover, the in vivo synergistic upconversion fluorescent and X-ray imaging of nude mice were demonstrated by subcutaneously and intravenously administrated the ligand-free nanorods. The X-ray signals were matched well with the upconversion signal, indicating the successfully synergistic bioimaging. The ex-vivo X-ray and upconversion fluorescent imaging of various organs revealed that the nanorods were mainly accumulated in liver and lung. More importantly, the blood vessel of the lung can be readily visualized when these ligand-free nanorods are intravenously injected. Apart from the synergistic X-ray and upconversion bioimaging, the ligand-free nanorods can also possess excellent paramagnetic property for potential magnetic resonance imaging contrast agent. Our results have demonstrated the enhanced visualization of blood vessel of lung performed by dual-modal bioimaging of X-ray and upconversion fluorescence, revealing the great promise of these nanoprobes in angiography imaging. Such a new technique enables the integration of the two bioimaging techniques by combining their collective strengths and minimizing their shortcomings. PMID:24406214

  5. Enhanced Ca2+-dependent activation of phosphoinositide 3-kinase class II? isoform-Rho axis in blood vessels of spontaneously hypertensive rats.

    PubMed

    Seok, Young Mi; Azam, Mohammed Ali; Okamoto, Yasuo; Sato, Atsushi; Yoshioka, Kazuaki; Maeda, Masataka; Kim, Inkyeom; Takuwa, Yoh

    2010-11-01

    Rho-mediated inhibition of myosin light chain (MLC) phosphatase (MLCP), together with Ca(2+)-dependent MLC kinase activation, constitutes the major signaling mechanisms for vascular smooth muscle contraction. We recently unveiled the involvement of Ca(2+)-induced, phosphoinositide 3-kinase (PI3K) class II? isoform (PI3K-C2?)-dependent Rho activation and resultant Rho kinase-dependent MLCP suppression in membrane depolarization- and receptor agonist-induced contraction. It is unknown whether Ca(2+)- and PI3K-C2?-dependent regulation of MLCP is altered in vascular smooth muscle of hypertensive animals and is involved in hypertension. Therefore, we studied the role of the Ca(2+)-PI3K-C2?-Rho-MLCP pathway in spontaneously hypertensive rats (SHRs). PI3K-C2? was readily detected in various vascular beds of Wistar-Kyoto rats and activated by high KCl. High KCl also stimulated vascular Rho activity and phosphorylation of the MLCP regulatory subunit MYPT1 at Thr(853) in a PI3K inhibitor wortmannin-sensitive manner. In mesenteric and other vessels of SHRs at the hypertensive but not the prehypertensive stage, the activity of PI3K-C2? but not class I PI3K p110? was elevated with concomitant rises of Rho activity and Thr(853)-phosphorylation of MYPT1, as compared with normotensive controls. Infusion of the Ca(2+) channel antagonist nicardipine reduced blood pressure with suppression of vascular activity of PI3K-C2?-Rho and phosphorylation of MYPT1 in hypertensive SHRs. Infusion of wortmannin lowered blood pressure with inhibition of PI3K-C2?-Rho activities and MYPT1 phosphorylation in hypertensive SHRs. These observations suggest that an increased activity of the Ca(2+)-PI3K-C2?-Rho signaling pathway with resultant augmented MLCP suppression contributes to hypertension in SHRs. The Ca(2+)- and PI3K-C2?-dependent Rho stimulation in vascular smooth muscle may be a novel, promising target for treating hypertension. PMID:20921425

  6. Construction of an Aptamer-SiRNA Chimera-Modified Tissue-Engineered Blood Vessel for Cell-Type-Specific Capture and Delivery.

    PubMed

    Chen, Wen; Zeng, Wen; Sun, Jiansen; Yang, Mingcan; Li, Li; Zhou, Jingting; Wu, Yangxiao; Sun, Jun; Liu, Ge; Tang, Rui; Tan, Ju; Zhu, Chuhong

    2015-06-23

    The application of tissue-engineered blood vessels (TEBVs) is the main developmental direction of vascular replacement therapy. Due to few and/or dysfunctional endothelial progenitor cells (EPCs), it is difficult to successfully construct EPC capture TEBVs in diabetes. RNA has a potential application in cell protection and diabetes treatment, but poor specificity and low efficiency of RNA transfection in vivo limit the application of RNA. On the basis of an acellular vascular matrix, we propose an aptamer-siRNA chimera-modified TEBV that can maintain a satisfactory patency in diabetes. This TEBV consists of two parts, CD133-adenosine kinase (ADK) chimeras and a TEBV scaffold. Our results showed that CD133-ADK chimeras could selectively capture the CD133-positive cells in vivo, and then captured cells can internalize the bound chimeras to achieve RNA self-transfection. Subsequently, CD133-ADK chimeras were cut into ADK siRNA by a dicer, resulting in depletion of ADK. An ADK-deficient cell may act as a bioreactor that sustainably releases adenosine. To reduce nonspecific RNA transfection, we increased the proportion of HAuCl4 during the material preparation, through which the transfection capacity of polyethylenimine (PEI)/polyethylene glycol (PEG)-capped gold nanoparticles (PEI/PEG-AuNPs) was significantly decreased and the ability of TEBV to resist tensile and liquid shear stress was greatly enhanced. PEG and 2'-O-methyl modification was used to enhance the in vivo stability of RNA chimeras. At day 30 postgrafting, the patency rate of CD133-ADK chimera-modified TEBVs reached 90% in diabetic rats and good endothelialization was observed. PMID:26051465

  7. Single peptide ligand-functionalized uniform hollow mesoporous silica nanoparticles achieving dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells

    PubMed Central

    Liu, Yang; Chen, Qing; Xu, Ming; Guan, Guannan; Hu, Wen; Liang, Ying; Zhao, Xiuli; Qiao, Mingxi; Chen, Dawei; Liu, Hao

    2015-01-01

    Background The purpose of this study was to construct hollow mesoporous silica nanoparticles (HMSN) decorated with tLyp-1 peptide (tHMSN) for dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells. Methods HMSN were synthesized de novo using a novel cationic surfactant-assisted selective etching strategy and were then modified with tLyp-1. Multiple methods, including transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, bicinchoninic acid assay, and nitrogen adsorption and desorption isotherms, were used to characterize the tHMSN. Doxorubicin were chosen as the model cargo, and the uptake of doxorubicin-loaded tHMSN into MDA-MB-231 cells and human umbilical vein endothelial cells (HUVECs), as models of tumor cells and tumor neovascular endothelial cells, respectively, were observed and detected by confocal laser scanning microscopy and flow cytometry. An in vitro pharmacodynamic study and a study of the mechanism via which the nanoparticles were endocytosed were also performed. Results HMSN with a highly uniform size and well oriented mesopores were synthesized. After tHMSN were characterized, enhanced uptake of the cargo carried by tHMSN into MDA-MB-231 cells and HUVECs compared with that of their unmodified counterparts was validated by confocal laser scanning microscopy and flow cytometry at the qualitative and quantitative levels, respectively. Further, the pharmacodynamic study suggested that, compared with their unmodified counterparts, doxorubicin-loaded tHMSN had an enhanced inhibitory effect on MDA-MB-231 cells and HUVECs in vitro. Finally, a preliminary study on the mechanism by which the nanoparticles were endocytosed indicated that the clathrin-mediated endocytosis pathway has a primary role in the transport of tHMSN into the cytoplasm. Conclusion tHMSN might serve as an effective active targeting nanocarrier strategy for anti-mammary cancer drug delivery. PMID:25834425

  8. Synthesis and characterization of copolymer materials from chitosan and polyethylene glycol: Evaluation of potential for use in man-made blood vessels; and modeling of cell-material dynamic interactions

    NASA Astrophysics Data System (ADS)

    Zhong, Jingfang

    2005-11-01

    Blood vessel may have multi-layer structure with one layer offering the necessary mechanical properties, and the most inner layer offering blood compatibility. One goal of the research was to get some basic information about the in-vivo blood interaction and degradation properties of 3 types of modified chitosan materials: chitosan-g-PEG with 54.2% PEG, chitosan ionically bound with heparin, and chitosan crosslinked by sebacic acid and ionically bound with heparin. For studying the in-vivo blood interaction properties, the materials were processed in the way of mimicking blood vessels as two-layer structure, with outer layer as porous structure, and inner layer as smooth dense structure that were made from one of the 3 types of materials. They were implanted into rats to replace part of blood vessels, and the results of blood vessel replacement were observed. In recent studies, chitosan has been found to be a promising base material for a number of tissue engineering applications. The goal of this investigation was to modify the elastic modulus of chitosan material without loss of strength to make chitosan material have different suitable elastic modulus for different biomedical applications. PEG side chains were grafted onto chitosan to make copolymer material. Copolymer's mechanical, micro-structural, cell interaction properties were investigated. It was found that with increasing PEG content, the elastic modulus decreased because the crystal structure in chitosan was destroyed by the grafted PEG chains. Copolymer showed effect on inhibiting smooth muscle cell growth comparing with unmodified chitosan. When PEG content changed only in the small range of 0--10%, the changes of both mechanical properties and cell interaction properties were already very significant. 3 dynamic models addressing both receptor and ligand mobility, and various reaction geometries were developed. Model was validated with published data on interaction between lymphocytes and membrane-immobilized ligand proteins. Test results showed that the model is valid, and it is a new method for measuring rate constant of receptor-ligand reaction and diffusion coefficient of protein.

  9. Large Vessel Pulmonary Arteritis

    Microsoft Academic Search

    Kim M. Kerr

    \\u000a Takayasu’s arteritis (TA) and giant cell arteritis (GCA) are the most well known large vessel vasculitides. Although similar\\u000a in histologic appearance, they have been divided into two distinct clinical entities on the basis of their age of onset, clinical\\u000a presentation, and distribution of vascular involvement. Although both may involve large and mediumsized arteries, including\\u000a the aorta and its branches, the

  10. Charting Blood's Through Blocked Vessels

    E-print Network

    Shaver, Gregory M.

    Nanotechnology Center, the School of Veterinary Medicine, and the IU School of Medicine. In the following pages: FACULTY Going With the Flow: Carl Wassgren's research may make 9 pharmaceuticals an easier pill to swallow

  11. Classification & Structure of Blood Vessels

    MedlinePLUS

    ... Central Nervous System Peripheral Nervous System Review Quiz Endocrine System Characteristics of Hormones Endocrine Glands & Their Hormones Pituitary & ... Thyroid & Parathyroid Glands Adrenal Gland Pancreas Gonads Other Endocrine Glands ... Cardiovascular System Heart Structure of the Heart Physiology of the ...

  12. The horseshoe vortex: a secondary flow generated in arteries with stenosis, bifurcation, and branchings.

    PubMed

    Fukushima, T; Azuma, T

    1982-01-01

    In order to elucidate the fluid dynamic feature of arterial blood flow, the present flow visualization study was carried out with various transparent blood vessel models having a protuberance, a bifurcation, or branchings. The observed flow patterns could be understood in terms of occurrence of a secondary flow, named the horseshoe vortex. The mode of generation of the horseshoe vortex in a tube with a protuberance projecting into the boundary layer was explained as follows. A radial pressure gradient toward the tube wall was produced along the upstream surface of the protuberance because of the interaction between the viscous sheared flow and the wall. This pressure gradient made fluid particles turn round downward directly before the obstacle. Then they curled round on themselves and formed a bound vortex tube, the horseshoe vortex, which in turn passed round the front of the protuberance in both directions. In a tube with a Y-shaped bifurcation or rectangular side branch, the flow divider at the branching site acted in place of the protuberance to produce a vortex tube similar in pattern to the horseshoe vortex. The vortex tube extended from the high pressure region, i. e. the apex of the flow divider, to the low pressure region, i. e. the lateral margin of the branch orifice, and generated swirling secondary flows in the main and branched tubes. These results suggested that the following mechanical factors might initiate or facilitate athero- and thrombogenesis: collision of blood cells captured by the horseshoe vortex with blood vessel walls, the interaction of the walls and blood cells due to turbulence, and the occurrence of localized high wall shear stresses. PMID:7093448

  13. Blood flow measurement and slow flow detection in retinal vessels with Joint Spectral and Time domain method in ultrahigh speed OCT

    E-print Network

    Gorczynska, I.

    We present an application of the Joint Spectral and Time domain OCT (STdOCT) method for detection of wide range of flows in the retinal vessels. We utilized spectral/Fourier domain OCT (SOCT) technique for development of ...

  14. Evaluation of arterial blood flow heterogeneity via an image-based computational model

    NASA Astrophysics Data System (ADS)

    Burrowes, Kelly S.; Tawhai, Merryn H.; Hunter, Peter J.

    2005-04-01

    A computational model of blood flow through the human pulmonary arterial tree has been developed to investigate the relative influence of branching structure and gravity on blood flow distribution in the human lung. A geometric model of the largest arterial vessels and definitions of the lobar boundaries were first derived using multi-detector row x-ray computed tomography (MDCT) scans from the Lung Atlas. Further accompanying arterial vessels were generated from the MDCT vessel end points into the lobar volumes using a volume filling branching algorithm. A reduced form of the Navier-Stokes equations were solved within the geometric model to simulate pressure, velocity and vessel radius throughout the network. Blood flow results in the anatomically-based model, with and without gravity, and in a symmetric arterial model were compared in order to investigate their relative contributions to blood flow heterogeneity. Results showed a persistent blood flow gradient and flow heterogeneity in the absence of gravitational forces in the anatomically-based model. Results revealed that the asymmetric branching structure of the model was largely responsible for producing this heterogeneity. Analysis of average results in different slice thicknesses illustrated a clear flow gradient due to gravity in 'lower-resolution" data (thicker slices), but on examination of higher resolution data a trend was less obvious. Results suggest that while gravity does influence flow distribution, the influence of the tree branching structure is also a dominant factor. These results are consistent with high-resolution experimental studies that have demonstrated gravity to be only a minor determinant of blood flow distribution.

  15. PDGF-C Induces Maturation of Blood Vessels in a Model of Glioblastoma and Attenuates the Response to Anti-VEGF Treatment

    PubMed Central

    di Tomaso, Emmanuelle; London, Nyall; Fuja, Daniel; Logie, James; Tyrrell, James A.; Kamoun, Walid; Munn, Lance L.; Jain, Rakesh K.

    2009-01-01

    Background Recent clinical trials of VEGF inhibitors have shown promise in the treatment of recurrent glioblastomas (GBM). However, the survival benefit is usually short-lived as tumors escape anti-VEGF therapies. Here we tested the hypothesis that Platelet Derived Growth Factor-C (PDGF-C), an isoform of the PDGF family, affects GBM progression independent of VEGF pathway and hinders anti-VEGF therapy. Principal Findings We first showed that PDGF-C is present in human GBMs. Then, we overexpressed or downregulated PDGF-C in a human GBM cell line, U87MG, and grew them in cranial windows in nude mice to assess vessel structure and function using intravital microscopy. PDGF-C overexpressing tumors had smaller vessel diameters and lower vascular permeability compared to the parental or siRNA-transfected tumors. Furthermore, vessels in PDGF-C overexpressing tumors had more extensive coverage with NG2 positive perivascular cells and a thicker collagen IV basement membrane than the controls. Treatment with DC101, an anti-VEGFR-2 antibody, induced decreases in vessel density in the parental tumors, but had no effect on the PDGF-C overexpressing tumors. Conclusion These results suggest that PDGF-C plays an important role in glioma vessel maturation and stabilization, and that it can attenuate the response to anti-VEGF therapy, potentially contributing to escape from vascular normalization. PMID:19352490

  16. ‘Cor placentale’: placental intervillus\\/intravillus blood flow mismatch is the pathophysiological mechanism in severe intrauterine growth restriction due to uteroplacental disease

    Microsoft Academic Search

    N. J. Sebire; D. Talbert

    2001-01-01

    The underlying pathophysiology in most cases of severe intrauterine growth restriction and pre-eclampsia is thought to be abnormal and inadequate conversion of the branches of the uterine arteries into low resistance uteroplacental vessels, due to poor extravillous trophoblastic invasion, leading to reduced intervillous blood flow. Since, in most vascular beds the main site of flow resistance is at the level

  17. Alkamides from Echinacea angustifolia Interact with P-glycoprotein of primary brain capillary endothelial cells isolated from porcine brain blood vessels.

    PubMed

    Mahringer, Anne; Ardjomand-Woelkart, Karin; Bauer, Rudolf; Fricker, Gert; Efferth, Thomas

    2013-03-01

    The blood-brain barrier prevents the passage of toxic compounds from blood circulation into brain tissue. Unfortunately, drugs for the treatment of neurodegenerative diseases, brain tumors, and other diseases also do not cross the blood-brain barrier. In the present investigation, we used isolated porcine brain capillary endothelial cells and a flow cytometric calcein-AM assay to analyze inhibition of P-glycoprotein, a major constituent of the blood-brain barrier. We tested 8 alkamides isolated from Echinacea angustifolia and found that four of them inhibited P-glycoprotein-mediated calcein transport in porcine brain capillary endothelial cells. PMID:23322561

  18. Computer-aided mesenteric small vessel segmentation on high-resolution 3D contrast-enhanced CT angiography scans

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Nguyen, Tan; Louie, Adeline; Wank, Stephen; Summers, Ronald M.

    2012-03-01

    Segmentation of the mesenteric vasculature has important applications for evaluation of the small bowel. In particular, it may be useful for small bowel path reconstruction and precise localization of small bowel tumors such as carcinoid. Segmentation of the mesenteric vasculature is very challenging, even for manual labeling, because of the low contrast and tortuosity of the small blood vessels. Many vessel segmentation methods have been proposed. However, most of them are designed for segmenting large vessels. We propose a semi-automated method to extract the mesenteric vasculature on contrast-enhanced abdominal CT scans. First, the internal abdominal region of the body is automatically identified. Second, the major vascular branches are segmented using a multi-linear vessel tracing method. Third, small mesenteric vessels are segmented using multi-view multi-scale vesselness enhancement filters. The method is insensitive to image contrast, variations of vessel shape and small occlusions due to overlapping. The method could automatically detect mesenteric vessels with diameters as small as 1 mm. Compared with the standard-of-reference manually labeled by an expert radiologist, the segmentation accuracy (recall rate) for the whole mesenteric vasculature was 82.3% with a 3.6% false positive rate.

  19. Simulating Blood Flow M.Sc. project

    E-print Network

    Lindken, Ralph

    Simulating Blood Flow M.Sc. project This project is intended for M Engineering. Blood flow plays a critical role in the development of aneurysms of the blood vessel wall. The forces due to blood flow can make aneurysms grow

  20. Direct evidence that complex experience increases capillary branching and surface area in visual cortex of young rats.

    PubMed

    Sirevaag, A M; Black, J E; Shafron, D; Greenough, W T

    1988-10-01

    Rats housed in complex environments with toys and other rats generate new synapses, and the expanding neuropil tends to spread apart existing blood vessels. Previous work demonstrated that weanling rats kept in complex environments had more closely packed capillaries, suggesting that new capillaries had sprouted into the newly added neuropil. The present study directly investigates the issue of new branching by using india ink perfusions of weanling rats kept for 30 days in a complex environment (EC), paired in standard caging (SC), or individual cages (IC) to examine the density of capillary branch points and the capillary surface area per unit tissue volume. EC rats had a greater density of branch points than the SC and IC littermates, a finding consistent with increased capillary sprouting. Capillary surface area per unit tissue volume and the number of branch points per unit of capillary surface area were also higher for EC rats. This suggests that blood vessels of EC rats branch off more often than those of animals kept in more standard conditions, and provides further evidence that complex experience can increase angiogenesis in cerebral cortex of postweanling rats. PMID:3179754

  1. The bipartite rac1 Guanine nucleotide exchange factor engulfment and cell motility 1/dedicator of cytokinesis 180 (elmo1/dock180) protects endothelial cells from apoptosis in blood vessel development.

    PubMed

    Schäker, Kathrin; Bartsch, Susanne; Patry, Christian; Stoll, Sandra J; Hillebrands, Jan-Luuk; Wieland, Thomas; Kroll, Jens

    2015-03-01

    Engulfment and cell motility 1/dedicator of cytokinesis 180 (Elmo1/Dock180) is a bipartite guanine nucleotide exchange factor for the monomeric GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1). Elmo1/Dock180 regulates Rac1 activity in a specific spatiotemporal manner in endothelial cells (ECs) during zebrafish development and acts downstream of the Netrin-1/Unc5-homolog B (Unc5B) signaling cascade. However, mechanistic details on the pathways by which Elmo1/Dock180 regulates endothelial function and vascular development remained elusive. In this study, we aimed to analyze the vascular function of Elmo1 and Dock180 in human ECs and during vascular development in zebrafish embryos. In vitro overexpression of Elmo1 and Dock180 in ECs reduced caspase-3/7 activity and annexin V-positive cell number upon induction of apoptosis. This protective effect of Elmo1 and Dock180 is mediated by activation of Rac1, p21-activated kinase (PAK) and AKT/protein kinase B (AKT) signaling. In zebrafish, Elmo1 and Dock180 overexpression reduced the total apoptotic cell and apoptotic EC number and promoted the formation of blood vessels during embryogenesis. In conclusion, Elmo1 and Dock180 protect ECs from apoptosis by the activation of the Rac1/PAK/AKT signaling cascade in vitro and in vivo. Thus, Elmo1 and Dock180 facilitate blood vessel formation by stabilization of the endothelium during angiogenesis. PMID:25586182

  2. Small-field angiographic imaging of tumor blood vessels in rabbit auricle using X-ray SATICON camera and synchrotron radiation

    Microsoft Academic Search

    K. Umetani; T. Yamashita; N. Maehara; R. Tokiya; S. Imai; Y. Kajihara

    2003-01-01

    Microangiography with spatial resolution in the micrometer range was carried out for depicting angiogenic vessels in a rabbit model of cancer using a high-resolution detector and a third generation synchrotron radiation source at SPring-8. The long source-to-object distance and small source spot of synchrotron radiation radiography are able to produce high-resolution images. The imaging system was composed of an X-ray

  3. Interdiction Branching

    E-print Network

    2011-09-29

    Sep 29, 2011 ... of partitioning the search space, referred to as the branching scheme. .... standard branch-and-bound both in terms of size of the enumeration tree and ...... of the fractional variable to be selected to enter at each iteration of the.

  4. Blood microcirculation of ischemic pancreatitis

    NASA Astrophysics Data System (ADS)

    Dmitrieva, Irina V.; Arakelian, Sergei M.; Antonov, Olga V.

    1998-06-01

    Blood Microcirculation includes many of different components, which are joined by unique multiple system. Capillaries are one of the main link in this morpho-functional chain. Changes in any components of blood microcirculation are revealed by many of pathological processes in different organs and systems of the whole organism. We investigated 250 patients from 30 to 77 ages. Men included 149, women -- 101. The main diagnosis of all patients was the ischaemic pancreatitis. For verification of this diagnosis we used the whole spectrum of clinical, laboratorial and instrumental methods. These were the following: the definition of amylase of blood and urine, sonography and computer's tomography of pancreas, angiography of vessels of pancreas and Doppler's sonography of abdominal aorta and her branches: arteria mesenterica superior (AMS), truncus coeliacus (TC), arteria hepatica communis (AHC) and arteria lienalis (AL). We investigated the blood microcirculation of the mucous of the inferior lip, using Laser Dopplerography. The equipment for this research was LACC-01 with modified computer's program. The normal levels of blood microcirculation were from 120 to 180 Units. But patients with ischaemic pancreatitis had more lower level than in normal situation. This method are suggested as express diagnostic in the cases of abdominal ischaemic pathology. It can used as singel method or in combined with ultrasound Dopplerography.

  5. Mechanisms of Vessel Pruning and Regression.

    PubMed

    Korn, Claudia; Augustin, Hellmut G

    2015-07-01

    The field of angiogenesis research has primarily focused on the mechanisms of sprouting angiogenesis. Yet vascular networks formed by vessel sprouting subsequently undergo extensive vascular remodeling to form a functional and mature vasculature. This "trimming" includes distinct processes of vascular pruning, the regression of selected vascular branches. In some situations complete vascular networks may undergo physiological regression. Vessel regression is an understudied yet emerging field of research. This review summarizes the state-of-the-art of vessel pruning and regression with a focus on the cellular processes and the molecular regulators of vessel maintenance and regression. PMID:26151903

  6. 46 CFR 129.420 - Branch circuits for lighting on OSVs of 100 or more gross tons.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Branch circuits for lighting on OSVs...OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Lighting... § 129.420 Branch circuits for lighting on OSVs...gross tons, each branch circuit for lighting must...

  7. 46 CFR 129.420 - Branch circuits for lighting on OSVs of 100 or more gross tons.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Branch circuits for lighting on OSVs...OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Lighting... § 129.420 Branch circuits for lighting on OSVs...gross tons, each branch circuit for lighting must...

  8. 46 CFR 129.420 - Branch circuits for lighting on OSVs of 100 or more gross tons.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Branch circuits for lighting on OSVs...OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Lighting... § 129.420 Branch circuits for lighting on OSVs...gross tons, each branch circuit for lighting must...

  9. 46 CFR 129.420 - Branch circuits for lighting on OSVs of 100 or more gross tons.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Branch circuits for lighting on OSVs...OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Lighting... § 129.420 Branch circuits for lighting on OSVs...gross tons, each branch circuit for lighting must...

  10. Doppler Ultrasound Detection of Side-Vessel Occlusion An In Vitro Study

    PubMed Central

    Chung, Emma M.L.; Ramnarine, Kumar V.; Long, Chloe V.; Udommongkol, Chesda; Chambers, Brian R.; Gittins, John; Bush, Glen C.; Evans, David H.

    2009-01-01

    Background and Purpose Small-vessel knock is a recently reported Doppler ultrasound finding that has been identified in patients with cerebral ischemia. It has been hypothesized that knock-type signals are linked to the presence of either small-vessel occlusion or wall motion. The aim of this study was to investigate the origins of “knock-type” signals by reproducing occlusion of a peripheral artery model in vitro. Methods Synthetic bifurcations were fabricated from glass and latex and placed in a flow-rig mimicking physiological blood-flow conditions. The glass model permitted study of fluid flow in the absence of wall motion, whereas the latex model also produced wall motion effects. Vessels were artificially obstructed to examine Doppler signal characteristics associated with blood flow and wall motion. Results Complete obstruction of the peripheral branch of the glass model revealed discrete (<100 ms) knock-type signals caused by local fluid flow in the occluded branch. Imaging of the obstructed vessel using color Doppler revealed forward and reflected flow. The walls produced periodic bidirectional knock-type signals, which occurred during systole and were not related to the presence of an obstruction. Conclusions In our laboratory model, transcranial Doppler ultrasound was found to be capable of detecting knock signals produced by circulating fluid within an occluded branch. However, because similar signals are also generated by nonpathological wall motion, these results cannot be directly translated to a clinical setting. Clinicians should be careful to avoid casual overinterpretation of transcranial Doppler ultrasound data. PMID:19095972

  11. Blood moves through the circulatory system

    NSDL National Science Digital Library

    Katie Hale (CSUF; )

    2007-08-18

    Arteries are blood vessels that carry blood away from the heart. Veins are blood vessels that carry blood to the heart. The circulatory system allows our organ systems to function by providing oxygen and other important nutrients required for metabolism, muscle contraction, and other functions.

  12. Defective Pericyte Recruitment of Villous Stromal Vessels as the Possible Etiologic Cause of Hydropic Change in Complete Hydatidiform Mole

    PubMed Central

    Kim, Kyu Rae; Sung, Chang Ohk; Kwon, Tae Jeong; Lee, JungBok; Robboy, Stanley J.

    2015-01-01

    The pathogenetic mechanism underlying the hydropic change in complete hydatidiform moles (CHMs) is poorly understood. A growing body of data suggests that pericytes play a role in vascular maturation. Since maturation of villous stromal vessels in CHMs is markedly impaired at early stages, we postulated that a defect in pericytes around stromal vessels in chorionic villi might cause vascular immaturity and subsequent hydropic change. To investigate this, we examined several markers of pericytes, namely, ?-smooth muscle actin (?-SMA), platelet-derived growth factor receptor-? (PDGFR-?), and desmin, in 61 normally developing placentas and 41 CHMs with gestational ages of 4–12 weeks. The ultrastructure of villous stromal vessels was also examined. Mature blood vessels from normal placentas show patent vascular lumens and formed hematopoietic components in the villous stroma. ?-SMA and PDGFR-? expression in the villous stroma gradually increased and extended from the chorionic plate to peripheral villous branches. The labeled cells formed a reticular network in the villous stroma and, after week 7, encircled villous stromal vessels. In comparison, ?-SMA and PDGFR-? expression in the villous stroma and stromal vessels of CHMs was significantly lower (p<0.05). Ultrastructurally, endothelial cells in villous stromal vessels in normal placentas were consistently attached by pericytes after week 7 when the vessels formed distinct lumen, whereas the villous stromal vessels in CHMs consisted of linear chains of endothelial cells, often disclosing primitive clefts without hematopoietic cells inside, and neither pericytes nor basal lamina surrounded the endothelial cells at any gestational age studied. This suggests that pericytes recruitment around villous stromal vessels is defective in CHMs and links to the persistent vascular immaturity of the villous stroma in CHMs, which in turns leads to hydropic villi. PMID:25849742

  13. Structure, Endothelial Function, Cell Growth, and Inflammation in Blood Vessels of Angiotensin II-Infused Rats Role of Peroxisome Proliferator-Activated Receptor

    Microsoft Academic Search

    Quy N. Diep; Mohammed El Mabrouk; Jeffrey S. Cohn; Dierk Endemann; Farhad Amiri; Agostino Virdis; Mario Fritsch Neves; Ernesto L. Schiffrin

    Background—Pioglitazone and rosiglitazone, thiazolidinedione peroxisome proliferator-activated receptor- (PPAR) activators, reduce blood pressure (BP) in some hypertensive models by unclear mechanisms. We tested the hypothesis that pioglitazone or rosiglitazone would prevent BP elevation and vascular dysfunction in angiotensin (Ang) II-infused rats by direct vascular effects. Methods and Results—Sprague-Dawley rats received Ang II (120 ng · kg1 · min1 SC) with or

  14. Optimizing 18F-FDG PET/CT Imaging of Vessel Wall Inflammation –The Impact of 18F-FDG Circulation Time, Injected Dose, Uptake Parameters, and Fasting Blood Glucose Levels

    PubMed Central

    Bucerius, Jan; Mani, Venkatesh; Moncrieff, Colin; Machac, Josef; Fuster, Valentin; Farkouh, Michael E.; Tawakol, Ahmed; Rudd, James H. F.; Fayad, Zahi A.

    2014-01-01

    Purpose 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used for imaging of vessel wall inflammation. However, limited data is available regarding the impact of methodological variables, i. e. patient’s pre-scan fasting glucose, the FDG circulation time, the injected FDG dose, and of different FDG uptake parameters, in vascular FDG-PET imaging. Methods 195 patients underwent vascular FDG-PET/CT of the aorta and the carotids. Arterial standard uptake values (meanSUVmax) as well as target-to-background-ratios (meanTBRmax) and the FDG blood pool activity in the superior vein cava (SVC) and the jugular veins (JV) were quantified. Vascular FDG uptake classified according to tertiles of patient’s pre-scan fasting glucose levels, the FDG circulation time, and the injected FDG dose was compared using ANOVA. Multivariate regression analyses were performed to identify the potential impact of all variables described on the arterial and blood pool FDG uptake. Results Tertile analyses revealed FDG circulation times of about 2.5 h and prescan glucose levels of less than 7.0 mmol/l showing favorable relations between the arterial and blood pool FDG uptake. FDG circulation times showed negative associations with the aortic meanSUVmax values as well as SVC- and JV FDG blood pool activity but a positive correlation with the aortic- and carotid meanTBRmax values. Pre-scan glucose was negatively associated with aortic- and carotid meanTBRmax and carotid meanSUVmax values, but correlated positively with the SVC blood pool uptake. Injected FDG dose failed to show any significant association with the vascular FDG uptake. Conclusion FDG circulation times and pre-scan blood glucose levels significantly impact FDG uptake within the aortic and carotid wall and may bias the results of image interpretation in patients undergoing vascular FDG-PET/CT. FDG dose injected was less critical. Therefore, circulation times of about 2.5 h and pre-scan glucose levels less than 7.0 mmol/l should be preferred in this setting. PMID:24271038

  15. Dual Labeling of Neural Crest Cells and Blood Vessels Within Chicken Embryos Using ChickGFP Neural Tube Grafting and Carbocyanine Dye DiI Injection.

    PubMed

    Delalande, Jean-Marie; Thapar, Nikhil; Burns, Alan J

    2015-01-01

    All developing organs need to be connected to both the nervous system (for sensory and motor control) as well as the vascular system (for gas exchange, fluid and nutrient supply). Consequently both the nervous and vascular systems develop alongside each other and share striking similarities in their branching architecture. Here we report embryonic manipulations that allow us to study the simultaneous development of neural crest-derived nervous tissue (in this case the enteric nervous system), and the vascular system. This is achieved by generating chicken chimeras via transplantation of discrete segments of the neural tube, and associated neural crest, combined with vascular DiI injection in the same embryo. Our method uses transgenic chick(GFP) embryos for intraspecies grafting, making the transplant technique more powerful than the classical quail-chick interspecies grafting protocol used with great effect since the 1970s. Chick(GFP)-chick intraspecies grafting facilitates imaging of transplanted cells and their projections in intact tissues, and eliminates any potential bias in cell development linked to species differences. This method takes full advantage of the ease of access of the avian embryo (compared with other vertebrate embryos) to study the co-development of the enteric nervous system and the vascular system. PMID:26065540

  16. [SKF-index as an indicator of biological age of hemostasis and blood vessels in children and adults in norm and pathology].

    PubMed

    Kuznik, B I; Fain, I A; Kaminski, A V; Maksimova, O G; Kustovskaya, E M

    2013-01-01

    A novel noninvasive method of an assessment of the hemostasis system and the vascular walls functioning is proposed. This method is based on the methodology of dynamic light scattering (DLS). New index SKF, which is derived from the previously established relationship between the intravascular mobility of the erythrocytes and the biological age, has been introduced. We demonstrated that the degree of the severity of the diseases correlates with the SKF index. More specifically, an increased value of the SKF index was found for the groups with cardio-vascular, oncological diseases and diabetes mellitus. In addition we provided evidences that the SKF index depends on the blood and plasma viscosity related to activity stage of the hemostasis system as well as on the functioning of the vascular walls. PMID:24000716

  17. Local control of blood flow

    NSDL National Science Digital Library

    Philip Clifford (Medical College of Wisconsin)

    2011-03-01

    Organ blood flow is determined by perfusion pressure and vasomotor tone in the resistance vessels of the organ. Local factors that regulate vasomotor tone include myogenic and metabolic autoregulation, flow-mediated and conducted responses, and vasoactive substances released from red blood cells. The relative importance of each of these factors varies over time, from tissue to tissue, and among vessel generations.

  18. 21 CFR 870.2120 - Extravascular blood flow probe.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...blood flow probe. (a) Identification. An extravascular blood flow probe is an extravascular ultrasonic or electromagnetic probe used in conjunction with a blood flowmeter to measure blood flow in a chamber or vessel. (b)...

  19. 21 CFR 870.2120 - Extravascular blood flow probe.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...blood flow probe. (a) Identification. An extravascular blood flow probe is an extravascular ultrasonic or electromagnetic probe used in conjunction with a blood flowmeter to measure blood flow in a chamber or vessel. (b)...

  20. Numerical Study on Flows of Red Blood Cells with Liposome-Encapsulated Hemoglobin at Microvascular Bifurcation

    NASA Astrophysics Data System (ADS)

    Hyakutake, Toru; Tani, Shigeki; Akagi, Yuki; Matsumoto, Takeshi; Yanase, Shinichiro

    2009-11-01

    Flow analysis at microvascular bifurcation after partial replacement of red blood cell (RBC) with liposome-encapsulated hemoglobin (LEH) was performed using the lattice Boltzmann method. A two-dimensional bifurcation model with a parent vessel and daughter branch was considered, and the distributions of the RBC, LEH, and oxygen fluxes were calculated. The immersed boundary method was employed to incorporate the fluid--membrane interaction between the flow field and deformable RBC When only RBCs flow into the daughter branches with unevenly distributed flows, plasma separation occurred and the RBC flow to the lower-flow branch was disproportionately decreased. On the other hand, when the half of RBC are replaced by LEH, the biasing of RBC flow was enhanced whereas LEH flowed favorably into the lower-flow branch, because many LEH within the parent vessel are suspended in the plasma layer, where no RBCs exist. Consequently, the branched oxygen fluxes became nearly proportional to flows. These results indicate that LEH facilitates oxygen supply to branches that are inaccessible to RBCs.

  1. Study of Stress Induced Failure of the Blood-gas Barrier and the Epithelial-epithelial Cells Connections of the Lung of the Domestic Fowl, Gallus gallus Variant Domesticus after Vascular Perfusion

    PubMed Central

    Maina, John N; Jimoh, Sikiru A

    2013-01-01

    Complete blood-gas barrier breaks (BGBBs) and epithelial-epithelial cells connections breaks (E-ECCBs) were enumerated in the lungs of free range chickens, Gallus gallus variant domesticus after vascular perfusion at different pressures. The E-ECCBs surpassed the BGBBs by a factor of ~2. This showed that the former parts of the gas exchange tissue were structurally weaker or more vulnerable to failure than the latter. The differences in the numbers of BGBBs and E-ECCBs in the different regions of the lung supplied with blood by the 4 main branches of the pulmonary artery (PA) corresponded with the diameters of the blood vessels, the angles at which they bifurcated from the PA, and the positions along the PA where they branched off. Most of the BGBBs and the E-ECCBs occurred in the regions supplied by the accessory- and the caudomedial branches: the former is the narrowest branch and the first blood vessel to separate from the PA while the latter is the most direct extension of the PA and is the widest. The E-ECCBs appeared to separate and fail from tensing of the blood capillary walls, as the perfusion- and intramural pressures increased. Compared to the mammalian lungs on which data are available, i.e., those of the rabbit, the dog, and the horse, the blood-gas barrier of the lung of free range chickens appears to be substantially stronger for its thinness. PMID:25288905

  2. A standalone perfusion platform for drug testing and target validation in micro-vessel networks

    PubMed Central

    Zhang, Boyang; Peticone, Carlotta; Murthy, Shashi K.; Radisic, Milica

    2013-01-01

    Studying the effects of pharmacological agents on human endothelium includes the routine use of cell monolayers cultivated in multi-well plates. This configuration fails to recapitulate the complex architecture of vascular networks in vivo and does not capture the relationship between shear stress (i.e. flow) experienced by the cells and dose of the applied pharmacological agents. Microfluidic platforms have been applied extensively to create vascular systems in vitro; however, they rely on bulky external hardware to operate, which hinders the wide application of microfluidic chips by non-microfluidic experts. Here, we have developed a standalone perfusion platform where multiple devices were perfused at a time with a single miniaturized peristaltic pump. Using the platform, multiple micro-vessel networks, that contained three levels of branching structures, were created by culturing endothelial cells within circular micro-channel networks mimicking the geometrical configuration of natural blood vessels. To demonstrate the feasibility of our platform for drug testing and validation assays, a drug induced nitric oxide assay was performed on the engineered micro-vessel network using a panel of vaso-active drugs (acetylcholine, phenylephrine, atorvastatin, and sildenafil), showing both flow and drug dose dependent responses. The interactive effects between flow and drug dose for sildenafil could not be captured by a simple straight rectangular channel coated with endothelial cells, but it was captured in a more physiological branching circular network. A monocyte adhesion assay was also demonstrated with and without stimulation by an inflammatory cytokine, tumor necrosis factor-?. PMID:24404058

  3. The effect of intravitreal bevacizumab on ocular blood flow in diabetic retinopathy and branch retinal vein occlusion as measured by laser speckle flowgraphy

    PubMed Central

    Nitta, Fumihiko; Kunikata, Hiroshi; Aizawa, Naoko; Omodaka, Kazuko; Shiga, Yukihiro; Yasuda, Masayuki; Nakazawa, Toru

    2014-01-01

    Background This study evaluated the effect of intravitreal injection of bevacizumab (IVB) on macular edema associated with diabetic retinopathy (DME) or branch retinal vein occlusion (BRVOME) using laser speckle flowgraphy. Methods A comparative interventional study of 25 eyes from 22 patients with macular edema (DME group: 12 eyes; BRVOME group: 13 eyes) who underwent IVB. Mean blur rate (MBR) was measured in the retinal artery, retinal vein, optic nerve head (ONH), and choroid before and after IVB. Results In the BRVOME group, there was no significant change in MBR in the retinal artery, retinal vein or ONH, but choroidal MBR decreased significantly (P=0.04). In the DME group, the MBR in the retinal artery, retinal vein, ONH, and choroid decreased significantly (P=0.02, P=0.04, P<0.001, and P=0.04, respectively). In the DME group, pre-IVB MBR in the ONH was significantly correlated with post-IVB foveal thickness (R= ?0.71, P=0.002). There was no such correlation in the BRVOME group in the ONH. Conclusion IVB had a suppressive effect on circulation in eyes with DME but not in those with BRVOME. This suggests that this noninvasive and objective biomarker may be a useful part of pre-IVB evaluations and decision-making in DME. PMID:24959068

  4. Measurement of vessel diameter of coronary arterial

    NASA Astrophysics Data System (ADS)

    Lu, Jianrong; Chen, Dongqing; Lu, Yangsheng; Cao, Maoyong

    2001-09-01

    The heart is the most important organ to our life. The coronary artery is the only path through which blood is provided to the heart. In the vessels of the heart especially the coronary artery, fluency of blood is mainly determined by vascular diameter and blood pressure. If blood is obstructed thus flows not freely due to vascular straitness, coronary heart disease would have a high occurrence among the aged people. Therefore, measurement of vessel diameter of coronary artery and the vascular parameters are of great importance of reflecting the function of the heart and disease diagnosis. In this paper, one novel and simple method to measure the coronary arterial diameter is presented and the relative difference of vessel (Dpi) is defined as one clinic diagnosis criterion for the degree of vascular straitness.

  5. An Activity on Factors Affecting Blood Flow

    NSDL National Science Digital Library

    Glenn Soltes

    2012-06-28

    This lesson is designed to explore the relationship between pressure and vessel diameter and to create a model that represents how high blood pressure may affect weakened vessels. A collaborative work of Melvin Flores, Larie Laudato and Glenn Soltes

  6. Micro-CT analysis of myocardial blood supply in young and adult rats

    NASA Astrophysics Data System (ADS)

    Schaefer, Heather M.; Beighley, Patricia E.; Eaker, Diane R.; Vercnocke, Andrew J.; Ritman, Erik L.

    2009-02-01

    This study addresses whether the vasculature grows in proportion to the myocardium as the rat heart develops. The volume of myocardium and coronary vessels were estimated from micro-CT images of the hearts injected with Microfil(R) contrast agent. Young (n=5) and adult (n=5) hearts were scanned, resulting in 3D images comprised of 20?m on-a-side cubic voxels. The myocardial muscle and vessel lumen volumes were measured for all vessels 40 to 320?m in diameter by an erosion and dilation method applied to the binary images in which the contrast in the vessels were assigned "1" and all non-opacified entities were assigned "0". The average total muscle volume increases by 50%, 129.4 to 237.4mm3, from young to adult rats, while the luminal volume increases by 10%, 16.6 to 18.6mm3. The vessel volume is 12% of the total muscle volume in young and 8% in adults. For a given vessel volume, the muscle volume in the young is 82% of the muscle volume in adults. We conclude that as the heart matures, the myocardium grows more rapidly than the vasculature. This may result in greater angles of separation between vessel branches, and the increase in myocardial coronary volume. The ratio suggests either higher blood flow velocity or a lower metabolic rate in adults.

  7. ‘In parallel’ interconnectivity of the dorsal longitudinal anastomotic vessels requires both VEGF signaling and circulatory flow

    PubMed Central

    Zygmunt, Tomasz; Trzaska, Sean; Edelstein, Laura; Walls, Johnathon; Rajamani, Saathyaki; Gale, Nicholas; Daroles, Laura; Ramírez, Craig; Ulrich, Florian; Torres-Vázquez, Jesús

    2012-01-01

    Summary Blood vessels deliver oxygen, nutrients, hormones and immunity factors throughout the body. To perform these vital functions, vascular cords branch, lumenize and interconnect. Yet, little is known about the cellular, molecular and physiological mechanisms that control how circulatory networks form and interconnect. Specifically, how circulatory networks merge by interconnecting ‘in parallel’ along their boundaries remains unexplored. To examine this process we studied the formation and functional maturation of the plexus that forms between the dorsal longitudinal anastomotic vessels (DLAVs) in the zebrafish. We find that the migration and proliferation of endothelial cells within the DLAVs and their segmental (Se) vessel precursors drives DLAV plexus formation. Remarkably, the presence of Se vessels containing only endothelial cells of the arterial lineage is sufficient for DLAV plexus morphogenesis, suggesting that endothelial cells from the venous lineage make a dispensable or null contribution to this process. The discovery of a circuit that integrates the inputs of circulatory flow and vascular endothelial growth factor (VEGF) signaling to modulate aortic arch angiogenesis, together with the expression of components of this circuit in the trunk vasculature, prompted us to investigate the role of these inputs and their relationship during DLAV plexus formation. We find that circulatory flow and VEGF signaling make additive contributions to DLAV plexus morphogenesis, rather than acting as essential inputs with equivalent contributions as they do during aortic arch angiogenesis. Our observations underscore the existence of context-dependent differences in the integration of physiological stimuli and signaling cascades during vascular development. PMID:22899709

  8. Computing Blood Flows

    NASA Technical Reports Server (NTRS)

    Kwak, D.; Chang, J. L. C.; Rogers, S. E.; Rosenfeld, M.

    1990-01-01

    Methods developed for aerospace applied to mechanics of biofluids. Report argues use of advanced computational fluid dynamics to analyze flows of biofluids - especially blood. Ability to simulate numerically and visualize complicated, time-varying three-dimensional flows contributes to understanding of phenomena in heart and blood vessels, offering potential for development of treatments for abnormal flow conditions.

  9. Interconnection of seasonal temperature, vascular traits, leaf anatomy and hydraulic performance in cut Dodonaea ‘Dana’ branches

    Microsoft Academic Search

    Ilana Shtein; Shimon Meir; Joseph Riov; Sonia Philosoph-Hadas

    2011-01-01

    Dodonaea ‘Dana’ is an Israeli hybrid with purple tinted leaves, cultivated for cut foliage branches. Cut Dodonaea branches showed strong seasonal variations in longevity, wilting after one week in winter, while displaying a vase life of three weeks in summer. We examined the relationship between functional anatomy, including vessel, stomata and trichome densities, vessel member length and leaf thickness, and

  10. Blood Circulatory System The circulatory system consists of

    E-print Network

    Cochran-Stafira, D. Liane

    Blood Circulatory System The circulatory system consists of: Heart Blood Vessels Blood Adults have 4-6 liters of blood. The study of blood is hematology What are the Functions of Blood Regulatory functions: Body temperature, water-salt balance, and body pH Composition of blood Formed

  11. Collagen-polymer guidance of vessel network formation and stabilization by endothelial colony forming cells in vitro.

    PubMed

    Whittington, Catherine F; Yoder, Mervin C; Voytik-Harbin, Sherry L

    2013-09-01

    Vessel morphogenesis is vital to regenerative medicine strategies. Here, collagen polymers, specified by intermolecular cross-link composition, are used to independently vary microstructure (fibril density, interfibril branching) and physical properties (stiffness) to guide 3D vessel network formation by endothelial colony forming cells (ECFC) in vitro. Increasing stiffness, by modulation of fibril density or interfibril branching, increases vessel diameter, length and branching. Oligomer matrices also induce vessel stabilization via type IV collagen deposition. This work shows that ECFC vessel formation depends on the interplay of collagen microstructure and physical properties and names oligomers and intermolecular cross-links as key design parameters for vascular-inductive matrices. PMID:23832790

  12. Branch cut surface placement for unwrapping of undersampled three-dimensional phase data: application to magnetic resonance imaging arterial flow mapping.

    PubMed

    Salfity, María F; Ruiz, Pablo D; Huntley, Jonathan M; Graves, Martin J; Cusack, Rhodri; Beauregard, Daniel A

    2006-04-20

    We demonstrate in both simulated and real cases the effect that undersampling of a three-dimensional (3D) wrapped phase distribution has on the geometry of phase singularity loops and their branch cut surfaces. The more intuitive two-dimensional (2D) problem of setting branch cuts between dipole pairs is taken as a starting point, and then branch cut surfaces in flat and ambiguous 3D loops are discussed. It is shown that the correct 2D branch cuts and 3D branch cut surfaces should be placed where the gradient of the original phase distribution exceeded pi rad voxel(-1). This information, however, is lost owing to undersampling and cannot be recovered from the sampled wrapped phase distribution alone. As a consequence, empirical rules such as finding the surface of minimal area or methods based on the wrapped phase gradient will fail to find the correct branch cut surfaces. We conclude that additional information about the problem under study is therefore needed to produce correct branch cut surfaces that lead to an unwrapped phase distribution with minimum local errors. An example with real data is provided in which downsampled phase contrast magnetic resonance imaging data are successfully unwrapped when the position of the vessel walls and the physical properties of the flowing blood are taken into account. PMID:16633421

  13. BIOASSAY VESSEL FAILURE ANALYSIS

    SciTech Connect

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  14. Salt May Be Bad for More Than Your Blood Pressure

    MedlinePLUS

    ... nlm.nih.gov/medlineplus/news/fullstory_151461.html Salt May Be Bad for More Than Your Blood ... develop high blood pressure from eating too much salt, you may still be damaging your blood vessels, ...

  15. The role of the arterial prestress in blood flow dynamics

    Microsoft Academic Search

    Giuseppe Pontrelli

    2006-01-01

    Blood flowing in a vessel is modelled using one-dimensional equations derived from the Navier–Stokes theory on the base of long pressure wavelength. The vessel wall is modelled as an initially highly prestressed elastic membrane, which slightly deforms under the blood pressure pulses. On the stressed configuration, the vessel wall undergoes, even in larger arteries, small deformation and its motion is

  16. Role of Arginase in Vessel Wall Remodeling

    PubMed Central

    Durante, William

    2013-01-01

    Arginase metabolizes the semi-essential amino acid l-arginine to l-ornithine and urea. There are two distinct isoforms of arginase, arginase I and II, which are encoded by separate genes and display differences in tissue distribution, subcellular localization, and molecular regulation. Blood vessels express both arginase I and II but their distribution appears to be cell-, vessel-, and species-specific. Both isoforms of arginase are induced by numerous pathologic stimuli and contribute to vascular cell dysfunction and vessel wall remodeling in several diseases. Clinical and experimental studies have documented increases in the expression and/or activity of arginase I or II in blood vessels following arterial injury and in pulmonary and arterial hypertension, aging, and atherosclerosis. Significantly, pharmacological inhibition or genetic ablation of arginase in animals ameliorates abnormalities in vascular cells and normalizes blood vessel architecture and function in all of these pathological states. The detrimental effect of arginase in vascular remodeling is attributable to its ability to stimulate vascular smooth muscle cell and endothelial cell proliferation, and collagen deposition by promoting the synthesis of polyamines and l-proline, respectively. In addition, arginase adversely impacts arterial remodeling by directing macrophages toward an inflammatory phenotype. Moreover, the proliferative, fibrotic, and inflammatory actions of arginase in the vasculature are further amplified by its capacity to inhibit nitric oxide (NO) synthesis by competing with NO synthase for substrate, l-arginine. Pharmacologic or molecular approaches targeting specific isoforms of arginase represent a promising strategy in treating obstructive fibroproliferative vascular disease. PMID:23717309

  17. Hydrodynamic interaction among blood cells in microcirculation

    Microsoft Academic Search

    Prosenjit Bagchi

    2005-01-01

    Particulate nature of blood plays an important role in many hemodynamic events in small vessels. One example is the Fahraeus-Lindqvist effect which arises due to the flow-induced deformation and lateral migration of red blood cells away from the vessel wall. The lateral migration creates a region of cell- free layer which has a reduced local viscosity, and thus a pronounced

  18. Tree-branch-searching multiresolution approach to skeletonization for virtual endoscopy

    NASA Astrophysics Data System (ADS)

    Chen, Dongqing; Li, Bin; Liang, Zhengrong; Wan, Ming; Kaufman, Arie E.; Wax, Mark R.

    2000-06-01

    One of the most important tasks for virtual endoscopy is path planning for viewing the lumen of hollow organs. For geometry complex objects, for example the lungs, it remains an unsolved problem. While alternative visualization modes have been proposed, for example, cutting and flattening the hollow wall, a skeleton of the lumen is still necessary as a reference for the cutting. A general-purpose skeletonization algorithm often generates redundant skeletons because of the local shape variation. In this study, a multistage skeletonization method for tree-like volumes, such as airway system, blood vessels, and colon, was presented. By appropriately defining the distance between voxels, the distance to the root from each voxel in the volume can be effectively determined with means of region growing techniques. The end points of all branches and the shortest path from each end point to the root can be extracted based on this distance map. A post-processing algorithm is applied to the shortest paths to remove redundant ones and to centralize the remained ones. The skeleton generated is one-voxel wide, along which every branch of the 'tree' can be viewed. For effectively processing volume of large size, a modified multiresolution analysis was also developed to scale down the binary segmented volume. Tests on airway, vessel, and colon dataset were promising.

  19. Handheld four-wavelength retinal vessel oximeter

    NASA Astrophysics Data System (ADS)

    Heaton, Larry C.; Smith, Matthew H.; Denninghoff, Kurt R.; Hillman, Lloyd W.

    2000-06-01

    Several techniques for measuring the oxygen saturation of blood in retinal vessels have been reported. One interesting application of retinal vessel oximetry is the identification of occult blood loss in trauma victims. However, all the devices described to date are too bulky and cumbersome to be used in a trauma bay or in the field. We present a design for a handheld instrument that performs four-wavelength retinal vessel oximetry. This device is comparable in size and weight to a commercially available camcorder, and is suitable for use in the trauma bay. The compact size of this device could also extend its applications beyond traditional clinical settings, as it could be used by primary care physicians and home health care workers for the screening and monitoring of ophthalmic diseases. Principles of operation and preliminary data from the device will be described.

  20. Checking Your Blood Sugar The only way to be sure your blood sugar is "just right" is to

    E-print Network

    Checking Your Blood Sugar The only way to be sure your blood sugar is "just right" is to check it. Your blood sugar can be high and you may feel fine. If your blood sugar is high, it is damaging your blood vessels and hurting your body, even if you feel fine. #12; How can you check your blood sugar? One

  1. Quantification of Retinopathy of Prematurity via Vessel Segmentation

    E-print Network

    of prematurity. Our technique captures the image of the retina to extract and quantify both tortuosity and dilation of blood vessels. Our approach demonstrates a 80% sensitivity and 92% specificity that tortuosity and dilation of retinal vessels are good predictors for ROP. Their sys- tem uses a lens to magnify

  2. Endothelial Cells of Tumor Vessels: Abnormal but not Absent

    Microsoft Academic Search

    Donald M. McDonald; Alexander J. E. Foss

    2000-01-01

    The question of whether some blood vessels in tumors of non-vascular origin are lined by cancer cells has been discussed for many years because of the relevance to metastasis, access of drugs to tumor cells, and the effectiveness of angiogenesis inhibitors. Most evidence favoring the existence of tumor cell-lined vessels has come from observations of standard histopathological tissue sections or

  3. VESSELS IN SOME ASLEPIADCEAE

    PubMed Central

    Nag, Anita; Kshetrapal, S.

    1990-01-01

    In the present investigation vessels of 16 species of family Asclepiadaceae have been studied. Through a lot of variation exists in the size and shape of vessels, number of perforation plates and intravascular thickening of walls in the taxa, the vessels in asclepiadaceae are found highly specified. PMID:22557694

  4. Neutrino Factory Mercury Vessel

    E-print Network

    McDonald, Kirk

    area ­ Space is available ­ If need 1 s to recool the He in a heat exchanger, need 3 kg, volume = 18 m3 vessel assumed to be cooled with Helium ­ Shielding vessel filled with tungsten beads ­ Mercury vessel-Battelle for the U.S. Department of Energy Cooling Calculations 15 Nov 2012 Helium Properties @ 20C http

  5. Reduced left internal mammary artery blood flow on normal sternal retraction.

    PubMed

    Kotkar, Kunal Deepak; Chaudhary, Ambuj; Brar, Rahat; Mahant, Tek Singh

    2015-03-01

    The left internal mammary artery is the conduit of choice for bypassing the left anterior descending artery. A 72-year-old man underwent off-pump triple-vessel coronary artery bypass. The left internal mammary artery was harvested with brisk blood flow from the distal artery on completion of harvesting, but normal sternal retraction with a Medtronic OctoBase retractor led to cessation of flow. A vein graft was utilized for the left anterior descending artery, and the internal mammary artery was grafted to the first diagonal branch. Computed tomography-angiography on postoperative day 5 demonstrated no possible cause of the reduced flow on sternal retraction. PMID:24887881

  6. Noninvasive blood flow measurement

    SciTech Connect

    Woodcock, J.P.

    1985-01-01

    The difficulties involved in measuring blood flow in vivo have meant that this important clinical measurement has not, as yet, played a major role in the clinical management of patients. Recent developments in the use of noninvasive techniques have now remedied this situation. These techniques are calorimetry, thermography, plethysmography, ultrasound, and nuclear magnetic resonance. They can be subdivided into those techniques which measure volume flow in a limb, organ, or tissue bed and those which are vessel specific. Because of these developments, information is now available on normal blood flow values in specific blood vessels and this can now be used to study blood flow changes in a variety of pathological conditions. 73 references.

  7. The road less traveled: importance of the lesser branches of the celiac axis in liver embolotherapy.

    PubMed

    Lee, Aram J; Gomes, Antoinette S; Liu, David M; Kee, Stephen T; Loh, Christopher T; McWilliams, Justin P

    2012-01-01

    Effective treatment of unresectable hepatic neoplasms depends on the appropriate identification of tumor arterial supply. Because hepatic tumors derive more than 90% of their blood supply from the hepatic arteries, awareness of common hepatic arterial anatomic variants (e.g., replaced or accessory left or right hepatic artery), as well as parasitized collateral vessels originating from the celiac axis (e.g., right inferior phrenic, omental, and cystic arteries) that can supply hepatic neoplasms-particularly those with a surface location-is important for safe and effective interventional therapy for these tumors. Moreover, recognition of certain nonhepatic branches arising from the hepatic arterial circulation is important for optimizing transarterial therapy and blocking the passage of treatment particles into sensitive structures, thereby preventing unwanted clinical sequelae such as gastrointestinal ulceration, skin ulceration or pain, and, rarely, ischemic cholecystitis. PMID:22786998

  8. Blood sampling techniques in reptiles

    Microsoft Academic Search

    H. J. Samour; D. Risley; T. March; B. Savage; O. Nieva; D. M. Jones

    1984-01-01

    Disposition of the superficial blood vessels was studied in 38 species of reptiles with a view to examining their suitability for taking blood samples. It was concluded that the coccygeal veins were probably the most suitable for this purpose and the precise techniques for sampling from the different orders are described.

  9. Local Control of Blood Flow

    ERIC Educational Resources Information Center

    Clifford, Philip S.

    2011-01-01

    Organ blood flow is determined by perfusion pressure and vasomotor tone in the resistance vessels of the organ. Local factors that regulate vasomotor tone include myogenic and metabolic autoregulation, flow-mediated and conducted responses, and vasoactive substances released from red blood cells. The relative importance of each of these factors…

  10. Calcitonin gene-related peptide acts as a novel vasodilator neurotransmitter in mesenteric resistance vessels of the rat

    Microsoft Academic Search

    Hiromu Kawasaki; Koichiro Takasaki; Akira Saito; Katsutoshi Goto

    1988-01-01

    Systemic blood pressure is controlled by changes in the resistance of the peripheral vascular bed for example in the mesenteric blood vessels1. The tone of peripheral blood vessels is primarily maintained by sympathetic vasoconstrictor nerves. Although vasodilator innervation has been identified in certain isolated elastic arteries2,3, it is not known whether vasodilator nerves contribute to the regulation of the peripheral

  11. Flattening Maps for the Visualization of Multibranched Vessels

    PubMed Central

    Zhu, Lei; Haker, Steven; Tannenbaum, Allen

    2013-01-01

    In this paper, we present two novel algorithms which produce flattened visualizations of branched physiological surfaces, such as vessels. The first approach is a conformal mapping algorithm based on the minimization of two Dirichlet functionals. From a triangulated representation of vessel surfaces, we show how the algorithm can be implemented using a finite element technique. The second method is an algorithm which adjusts the conformal mapping to produce a flattened representation of the original surface while preserving areas. This approach employs the theory of optimal mass transport. Furthermore, a new way of extracting center lines for vessel fly-throughs is provided. PMID:15707245

  12. [Echogenicity of blood].

    PubMed

    Battino, J

    1992-12-01

    The echogenicity of blood is dependent of the back scattering of the ultra-sound beam by the flowing blood-stream. This black scattering is, according to the Rayleigh theory, proportional to the fourth power of the frequency and to the size of the particles. So, for the frequencies in clinical use, the size of the particles is essential. Micro bubbles and aggregates of red cells can be echogenic. Micro bubbles are scare. Echoes are mainly generated by blood cells aggregated from a given size for each wave length. For instance, 225 for 7.5 MHz frequency. High degree hematocrits and big molecules induce aggregation, but the main factor is the flow speed or more exactly the shear rate, i.e. 8/3 of speed/vessel radius. In clinical practice, blood becomes echogenic if flow slows and if the vessel radius increases. This happens for instance for venous or even arterial aneurysms, for dilated and dyskinetic cardiac cavities, an above all, in veins when flow slows. Echogenicity appears proximal to an organic or hemodynamic obstacle and is reversible when flow is restored. The technical conditions are important, too. Blood becomes more echogenic when the scan benears, the frequency increases and the resolution of the device goes higher. It can be expected that hemodynamic and even rheologic information will be obtainable in big vessels with computerized techniques quantifying blood echogenicity. Blood clots will be echogenic under the same conditions: red blood cells aggregated non hemolyzed. Their echogenicity appears more dependent of their structure than of the chronology. Better technical conditions will increase the clot echogenicity, too. Therapeutic and prognostic conclusions can be expected by better evaluation of prethrombotic stages and of structure of blood clots. PMID:1301445

  13. Towards Vessel Characterisation in the Vicinity of the Optic Disc in Digital Retinal Images

    Microsoft Academic Search

    H. F. Jelinek; C. Depardieu; C. Lucas; D. J. Cornforth; W. Huang; M. J. Cree

    Automated image processing has the potential to assist in the early detection of diabetes, by detecting changes in blood vessel patterns in the retina. This paper describes progress towards the development of an integrated automated analyser of the retinal blood vessels in the vicinity of the optic disc using digital colour retinal images. First the optic disc was detected using

  14. A Novel Vessel Segmentation Algorithm for Pathological Retina Images Based on the Divergence of Vector Fields

    Microsoft Academic Search

    Benson Shu Yan Lam; Hong Yan

    2008-01-01

    In this paper, a method is proposed for detecting blood vessels in pathological retina images. In the proposed method, blood vessel-like objects are extracted using the Laplacian operator and noisy objects are pruned according to the centerlines, which are detected using the normalized gradient vector field. The method has been tested with all the pathological retina images in the publicly

  15. A wall-less vessel phantom for Doppler ultrasound studies

    Microsoft Academic Search

    D. W. Rickey; P. A. Picot; D. A. Christopher; A. Fenster

    1995-01-01

    Doppler ultrasound flow measurement techniques are often validated using phantoms that simulate the vasculature, surrounding tissue and blood. Many researchers use rubber tubing to mimic blood vessels because of the realistic acoustic impedance, robust physical properties and wide range of available sizes. However, rubber tubing has a very high acoustic attenuation, which may introduce artefacts into the Doppler measurements. We

  16. Chief, Biostatistics Branch

    Cancer.gov

    The Branch Chief directs an intramural research program, provides leadership and facilitates research activities of Branch scientists, and plans and directs independent statistical and computational research. In addition to overseeing the administrative management of the Branch, responsibilities include supervising staff members, mentoring tenure-track investigators and postdoctoral fellows, and ensuring the scientific quality of the Branch research portfolio. The Chief also plays a major role in ensuring the epidemiologic and methodologic rigor of research across DCEG.

  17. Branching Rules for Satisfiability

    Microsoft Academic Search

    John N. Hooker; V. Vinay

    1995-01-01

    Recent experience suggests that branching algorithms are among the most attractivefor solving propositional satisfiability problems. A key factor in their success is the rulethey use to decide on which variable to branch next. We attempt to explain and improvethe performance of branching rules with an empirical model-building approach. Onemodel is based on the rationale given for the Jeroslow-Wang rule, variations

  18. VESSELS IN SOME APOCYNACEAE

    PubMed Central

    Nag, Anita; Kshetrapal, Shashikala

    1988-01-01

    In the present investigation vessels of 24 species of the family Apocynaceae have been studied. Lot of variation exist in the size and shape of vessels, number of perforation plates and intervascular thickening of walls in the taxa of Apocynaceae. PMID:22557619

  19. Muliscale Vessel Enhancement Filtering

    Microsoft Academic Search

    Alejandro F. Frangi; Wiro J. Niessen; Koen L. Vincken; Max A. Viergever

    1998-01-01

    The multiscale second order local structure of an image (Hessian )i s ex- amined with the purpose of developing a vessel enhancement filter. A vesselness mea- sure is obtained on the basis of all eigenvalues of the Hessian. This measure is tested on two dimensional DSA and three dimensional aortoiliac and cerebral MRA data. Its clinical utility is shown by

  20. Dual shell pressure balanced vessel

    DOEpatents

    Fassbender, Alexander G. (West Richland, WA)

    1992-01-01

    A dual-wall pressure balanced vessel for processing high viscosity slurries at high temperatures and pressures having an outer pressure vessel and an inner vessel with an annular space between the vessels pressurized at a pressure slightly less than or equivalent to the pressure within the inner vessel.

  1. [Echogenicity of blood].

    PubMed

    Battino, J

    1991-01-01

    The echogenicity of blood is dependent of the back scattering of the ultra-sound beam by the flowing blood-stream. This back scattering is, according to the Raleigh theory, proportional to the fourth power of the frequency and to the size of the particles. So, for the frequencies in clinical use, the size of the particles is essential. Micro bubbles and aggregates of red cells can be echogenic. Micro bubbles are scare. Echoes are mainly generated by blood cells aggregated from a given size for each wave length. For instance, 225 for a 7.5 Mhz frequency. High degree hematocrits and big molecules induce aggregation, but the main factor is the flow speed or more exactly the shear rate, i.e. 8/3 of speed/vessel radius. In clinical practice, blood becomes echogenic if flow slows and if the vessel radius increases. This happens for instance for venous or even arterial aneurysms, for dilatated and dyskinetic cardiac cavities, an above all, in veins when flow slows. Echogenicity appears proximal to an organic or hemodynamic obstacle and is reversible when flow is restored. The technical conditions are important, too. Blood becomes more echogenic when the scan nears, the frequency increases and the resolution of the device goes higher. It can be expected that hemodynamic and even rheologic information will be obtainable in big vessels with computerized techniques quantifying blood echogenicity. Blood clots will be echogenic under the same conditions: red blood cells aggregated non hemolysed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1791368

  2. Branching Out : Greenspace on Referral

    E-print Network

    Branching Out : Greenspace on Referral Hugh McNish, Health Advisor, Forestry Commission Scotland Kirsty Cathrine, Branching Out Programme Manager, Forestry Commission Scotland Neil Wilson, Assistant Psychologist, NHS Greater Glasgow & Clyde #12;Branching Out #12;Rationale for Branching Out intervention

  3. Confinement Vessel Dynamic Analysis

    SciTech Connect

    R. Robert Stevens; Stephen P. Rojas

    1999-08-01

    A series of hydrodynamic and structural analyses of a spherical confinement vessel has been performed. The analyses used a hydrodynamic code to estimate the dynamic blast pressures at the vessel's internal surfaces caused by the detonation of a mass of high explosive, then used those blast pressures as applied loads in an explicit finite element model to simulate the vessel's structural response. Numerous load cases were considered. Particular attention was paid to the bolted port connections and the O-ring pressure seals. The analysis methods and results are discussed, and comparisons to experimental results are made.

  4. Reactor vessel support system

    DOEpatents

    Golden, Martin P. (Trafford, PA); Holley, John C. (McKeesport, PA)

    1982-01-01

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  5. Structural and spatial organisation of brain parenchymal vessels in the lizard, Podarcis sicula: a light, transmission and scanning electron microscopy study

    PubMed Central

    LAZZARI, MAURIZIO; FRANCESCHINI, VALERIA

    2000-01-01

    The structure and 3-dimensional pattern of the intraparenchymal microvessels in the brain of the lizard, Podarcis sicula, were studied by a combination of light and transmission electron microscopy as well as scanning electron microscopy of vascular corrosion casts. The angioarchitecture pattern consists of narrow hairpin-shaped microvascular loops of different length originating from the meningeal surface. In each loop, descending and ascending vessels are closely apposed to one another throughout their length and are connected by a narrow U-shaped terminal loop at their tips. The 2 limbs of the vessel pairs show a slightly different diameter but lack other structural differences. While some paired vessels give rise to a secondary hairpin-shaped loop with 2 possible branching patterns, there are no anastomotic intraparenchymal connections with analogous neighbouring structures. The cerebral vascular pattern of Podarcis sicula resembles that found in a few representatives of other vertebrate classes. All cerebral vessels structurally appear to be capillaries. Also the observations carried out on semithin and thin sections strongly support the capillary loop model in the Podarcis brain vasculature and, in accordance with studies carried out on various vertebrates, the general submicroscopic features of the brain capillary wall suggest the presence of an endothelial type blood-brain barrier. PMID:11005709

  6. Blood Disorders

    MedlinePLUS

    ... blood cells, white blood cells and platelets. Blood disorders affect one or more parts of the blood ... They can be acute or chronic. Many blood disorders are inherited. Other causes include other diseases, side ...

  7. Blood Transfusions

    MedlinePLUS

    ... their blood . Donors give blood at local blood banks, at community centers during blood drives, or through ... in the world. Many organizations, including community blood banks and the federal government, work hard to ensure ...

  8. Blood Tests

    MedlinePLUS

    ... t have serious reactions to having blood drawn. Laboratory (lab) workers draw the blood and analyze it. They use either whole blood to count blood cells, or they separate the blood cells from the ...

  9. Serotonin, atherosclerosis, and collateral vessel spasm

    NASA Technical Reports Server (NTRS)

    Hollenberg, N.

    1988-01-01

    Studies on animal models demonstrate that platelet products contribute to vascular spasm in ischemic syndromes and that this is reversible with administration of ketanserin and thromboxane synthesis inhibitors. Laboratory animals (dogs, rabbits, and rats) that had femoral artery ligations exhibited supersensitivity to serotonin within days in their collateral blood vessels. This supersensitivity lasted at least 6 months. The response to serotonin was reversed by ketanserin, but not by 5HT-1 antagonists. Supersensitivity does not extend to norepinephrine, and alpha blockers do not influence the response to serotonin. It appears that platelet activation by endothelial injury contributes to ischemia through blood vessel occlusion and vascular spasm. When platelet activation occurs in vivo, blood vessel occlusion and vascular spasm are reversible in part by using ketanserin or agents that block thromboxane synthesis or its action. Combining both classes of agents reverses spasm completely. These findings support existing evidence that platelet products contribute to vascular disease, and provide an approach to improved management with currently available pharmacologic agents.

  10. Small vessel vasculitis

    PubMed Central

    Eleftheriou, Despina; Dillon, Michael

    2009-01-01

    The pediatric small vessel vasculitides reviewed in this article are Henoch–Schönlein purpura (HSP) and the anti-neutrophil cytoplasmic antibody-associated vasculitides (AAV). The new classification criteria for HSP and Wegener’s granulomatosis are now validated and will facilitate the conduct of future epidemiological studies and clinical trials. The clinical manifestations of small vessel vasculitis in children are described, and current therapies discussed. There is a lack of good clinical trial data on which to base therapy for HSP. Similarly, data based on randomized controlled trials (RCTs) for pediatric AAV are lacking, although children with AAV are for the first time now included in a RCT of mycophenolate mofetil versus cyclophosphamide. Significant challenges remain in the field of pediatric small vessel vasculitis, including the development of validated disease outcome measures and biomarkers to be used in clinical trials. Lastly, long-term outcome data are lacking in survivors of pediatric small vessel vasculitis. PMID:19885685

  11. Numerical Simulation of Unsteady Blood Flow through Capillary Networks.

    PubMed

    Davis, J M; Pozrikidis, C

    2010-11-01

    A numerical method is implemented for computing unsteady blood flow through a branching capillary network. The evolution of the discharge hematocrit along each capillary segment is computed by integrating in time a one-dimensional convection equation using a finite-difference method. The convection velocity is determined by the local and instantaneous effective capillary blood viscosity, while the tube to discharge hematocrit ratio is deduced from available correlations. Boundary conditions for the discharge hematocrit at divergent bifurcations arise from the partitioning law proposed by Klitzman and Johnson involving a dimensionless exponent, q?1. When q=1, the cells are partitioned in proportion to the flow rate; as q tends to infinity, the cells are channeled into the branch with the highest flow rate. Simulations are performed for a tree-like, perfectly symmetric or randomly perturbed capillary network with m generations. When the tree involves more than a few generations, a supercritical Hopf bifurcation occurs at a critical value of q, yielding spontaneous self-sustained oscillations in the absence of external forcing. A phase diagram in the m-q plane is presented to establish conditions for unsteady flow, and the effect of various geometrical and physical parameters is examined. For a given network tree order, m, oscillations can be induced for a sufficiently high value of q by increasing the apparent intrinsic viscosity, decreasing the ratio of the vessel diameter from one generation to the next, or by decreasing the diameter of the terminal vessels. With other parameters fixed, oscillations are inhibited by increasing m. The results of the continuum model are in excellent agreement with the predictions of a discrete model where the motion of individual cells is followed from inlet to outlet. PMID:21061079

  12. Ups and Downs of Guided Vessel Sprouting: The Role of Polarity

    NSDL National Science Digital Library

    Christina Y Lee (The University of North Carolina at Chapel Hill Department of Biology)

    2011-10-01

    Blood vessel networks expand to meet oxygen demands via sprouting angiogenesis. This process is heterogeneous but not random; as sprouts form and extend, neighboring endothelial cells do not sprout but divide. Sprouting is regulated by local sprout guidance cues produced by the vessels themselves, as well as extrinsic cues. Endothelial cells in developing vessels orient in several axes to establish migratory polarity, apical-basolateral polarity, and planar cell polarity. Although little is known about how polarity axes are set up or maintained, they are important for vessel formation and function. This review focuses on the current knowledge of how blood vessel sprouting is regulated and guided, the role of endothelial cell polarity in forming vessels, and how these processes affect vessel function and are potentially perturbed in pathologies with vascular components.

  13. Blood Flow in the Stenotic Carotid Bifurcation

    Microsoft Academic Search

    Vitaliy Rayz

    2005-01-01

    The carotid artery is prone to atherosclerotic disease and the growth of plaque in the vessel, leading often to severe occlusion or plaque rupture, resulting in emboli and thrombus, and, possibly, stroke. Modeling the flow in stenotic blood vessels can elucidate the influence of the flow on plaque growth and stability. Numerical simulations are carried out to model the complex

  14. Regulatory Affairs Branch (RAB)

    Cancer.gov

    Jan Casadei, PhD joined the National Cancer Institute in 1991, where she is now chief of the Regulatory Affairs Branch, CTEP. Her area of expertise covers FDA regulations, policies and guidelines for the conduct of clinical studies with investigational agents. As the chief of the Regulatory Affairs Branch, Dr.

  15. Blood flow dynamics in the snake spectacle.

    PubMed

    van Doorn, Kevin; Sivak, Jacob G

    2013-11-15

    The eyes of snakes are shielded beneath a layer of transparent integument referred to as the 'reptilian spectacle'. Well adapted to vision by virtue of its optical transparency, it nevertheless retains one characteristic of the integument that would otherwise prove detrimental to vision: its vascularity. Given the potential consequence of spectacle blood vessels on visual clarity, one might expect adaptations to have evolved that mitigate their negative impact. Earlier research demonstrated an adaptation to their spatial layout in only one species to reduce the vessels' density in the region serving the foveal and binocular visual fields. Here, we present a study of spectacle blood flow dynamics and provide evidence of a mechanism to mitigate the spectacle blood vessels' deleterious effect on vision by regulation of blood flow through them. It was found that when snakes are at rest and undisturbed, spectacle vessels undergo cycles of dilation and constriction, such that the majority of the time the vessels are fully constricted, effectively removing them from the visual field. When snakes are presented with a visual threat, spectacle vessels constrict and remain constricted for longer periods than occur during the resting cycles, thus guaranteeing the best possible visual capabilities in times of need. Finally, during the snakes' renewal phase when they are generating a new stratum corneum, the resting cycle is abolished, spectacle vessels remain dilated and blood flow remains strong and continuous. The significance of these findings in terms of the visual capabilities and physiology of snakes is discussed. PMID:24172887

  16. Regional variation in human retinal vessel oxygen saturation.

    PubMed

    Shahidi, A M; Patel, S R; Flanagan, J G; Hudson, C

    2013-08-01

    The purpose of this study was to investigate regional differences in oxygen saturation of blood in first degree retinal vessels using a novel non-flash hyperspectral retinal camera (Photon etc Inc). Nine healthy individuals (mean age 24.4 ± 3.6 yrs, 5 males) were imaged at 548, 569, 586, 600, 605 and 610 nm wavelengths. Optical density values were extracted with the aid of Image-J software for blood oxygen saturation (SO2) determination. Arteriolar and venular SO2 were measured at three locations (ranging 1-3 optic nerve head radii) from the disc margin along the vessels in the superior and inferior temporal quadrants. Retinal SO2 was significantly higher in the superior temporal arteriole and venule as compared to the inferior temporal vessels (p = 0.033 and p = 0.032 for arterioles and venules, respectively). SO2 was not significantly different between the three measurement sites for any of the given vessels imaged (p > 0.05). In conclusion, greater SO2 values were found in the superior temporal first degree retinal arterioles and venules in young healthy individuals than in the equivalent inferior vessels. However, there were no detectable differences in retinal SO2 along each of the major vessels, a finding that is consistent with the concept of these vessels not contributing primarily to gas exchange. Moreover, the SO2 was consistently higher in the arterioles than in the equivalent venules (p < 0.0001). PMID:23791637

  17. Movement of Blood cells (view at the cellular level)

    NSDL National Science Digital Library

    Katie Hale (CSUF; )

    2007-08-18

    The circulatory system of humans is closed, meaning that blood is enclosed by blood vessels. This image is that of an open system, meaning the blood moves freely throughout the body. In both systems, blood is pumped to the tissues of the body and then nutrients diffuse into the cells of those tissues.

  18. Celiac trunk and branches dissection due to energy drink consumption and heavy resistance exercise: case report and review of literature.

    PubMed

    González, Wilma; Altieri, Pablo I; Alvarado, Enrique; Banchs, Héctor L; Colón, Edgar; Escobales, Nelson; Crespo, María

    2015-01-01

    Higher doses and consumption of energy drinks leads to cardiovascular effects and potential consequences. Principal components found in energy drinks such as caffeine, guarana and taurine has been related to dilatation, aneurysm formation, dissection and ruptures. There is no evidence showing an integration of these components and its effects in endothelium and aortic walls due to higher levels of pressure during exercises. We report a case of a 44 years male with celiac trunk and branches dissection due to long-term consumption of energy drinks and intense exercise routine. Our proposition relates cell and vessel walls alterations including elasticity in endothelial wall due to higher blood pressure, resistance by intense exercise routine and long-term consumption of energy drinks. PMID:26035983

  19. Stellarator helical vacuum vessel

    SciTech Connect

    Yavornik, E.J.

    1983-01-01

    A design study of a stainless steel, heavy wall, helically shaped vacuum torus has been made for use in a proposed Stellarator configuration. The study concerns itself with the shape of the vacuum vessel and the division of the vessel into components that can be machined and welded together into a helical configuration. A complication in the design requires that a circular magnet coil be located at the minor toroidal axis and that this coil be embedded within the periphery of the vacuum vessel. The vacuum vessel has a minor toroidal axis diameter of 4 meters, a 68.6-cm shell diameter, and a 1.9-cm wall thickness. It twists about the minor toroidal axis twice in 360/sup 0/C. (An n value of 2). It is proposed that the unit be made of cylindrical segments with the ends of the cylinders cut at appropriate lengths and angles to form the helix. A mathematical derivation of the dimensions necessary to produce the required shapes of the segments has been made. Also, drawings of the vacuum vessel components have been produced on LANL's CTR CAD/CAM system. The procedure developed can be used for any value of n as dictated by physics requirements.

  20. Acrylic vessel cleaning tests

    SciTech Connect

    Earle, D.; Hahn, R.L.; Boger, J.; Bonvin, E.

    1997-02-26

    The acrylic vessel as constructed is dirty. The dirt includes blue tape, Al tape, grease pencil, gemak, the glue or residue form these tapes, finger prints and dust of an unknown composition but probably mostly acrylic dust. This dirt has to be removed and once removed, the vessel has to be kept clean or at least to be easily cleanable at some future stage when access becomes much more difficult. The authors report on the results of a series of tests designed: (a) to prepare typical dirty samples of acrylic; (b) to remove dirt stuck to the acrylic surface; and (c) to measure the optical quality and Th concentration after cleaning. Specifications of the vessel call for very low levels of Th which could come from tape residues, the grease pencil, or other sources of dirt. This report does not address the concerns of how to keep the vessel clean after an initial cleaning and during the removal of the scaffolding. Alconox is recommended as the cleaner of choice. This acrylic vessel will be used in the Sudbury Neutrino Observatory.

  1. The role of the arterial prestress in blood flow dynamics

    Microsoft Academic Search

    Giuseppe Pontrelli

    Abstract Blood flowing in a vessel is modelled,using one-dimensional equations derived from the Navier–Stokes theory on the base of long pressure wavelength. The vessel wall is modelled as an initially highly prestressed elastic membrane, which slightly deforms under the blood pressure pulses. On the stressed configuration, the vessel wall undergoes, even in larger arteries, small deformation and its motion is

  2. 69 FR 32031 - National Heart, Lung, and Blood Institute (NHLBI); Opportunity for a Cooperative Research and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-06-08

    ...National Institutes of Health National Heart, Lung, and Blood Institute (NHLBI...Medicine Branch (P-CCMB) in National Heart, Lung, and Blood Institute (NHLBI...Technology Transfer Specialist, National Heart, Lung, and Blood Institute...

  3. 69 FR 9830 - National Heart, Lung, and Blood Institute (NHLBI); Opportunity for a Cooperative Research and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-03-02

    ...National Institutes of Health National Heart, Lung, and Blood Institute (NHLBI...Medicine Branch (P-CCMB) in National Heart, Lung, and Blood Institute (NHLBI...Technology Transfer Specialist, National Heart, Lung, and Blood Institute...

  4. 75 FR 29356 - National Heart, Lung, and Blood Institute; Notice of Closed Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-25

    ...and Blood Initial Review Group; Heart, Lung, and Blood Program Project...Review Branch/DERA, National Heart, Lung, and Blood Institute...Disorders Research; 93.837, Heart and Vascular Diseases Research; 93.838, Lung...

  5. 75 FR 16152 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  6. 76 FR 61722 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-05

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch, DERA, National Heart, Lung, and Blood Institute, 6701...

  7. 75 FR 50771 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-17

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  8. 75 FR 9907 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  9. 75 FR 36427 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  10. 75 FR 28260 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  11. 75 FR 52957 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  12. 75 FR 61507 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch, DERA, National Heart, Lung, and Blood Institute, 6701...

  13. 76 FR 12123 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  14. 76 FR 16631 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  15. 76 FR 12744 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  16. 78 FR 69431 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-19

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Office of Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  17. 75 FR 4092 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  18. 75 FR 31796 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  19. 75 FR 42756 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...

  20. 76 FR 29772 - National Heart, Lung, and Blood Institute; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ...National Institutes of Health National Heart, Lung, and Blood Institute; Notice of...privacy. Name of Committee: National Heart, Lung, and Blood Institute Special Emphasis...Officer, Review Branch/DERA, National Heart, Lung, and Blood Institute, 6701...