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1

Branching Blood Vessels  

NSDL National Science Digital Library

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.

Mr. Jonathan Borne (Union Springs Academy)

2000-08-01

2

Histamine metabolism influences blood vessel branching in zebrafish reg6 mutants  

PubMed Central

Background Vascular branching morphogenesis is responsible for the extension of blood vessels into growing tissues, a process crucial 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 vessel lumina during capillary plexus formation. Results We performed a screening for chemical suppressors of reg6 and identified SKF91488, an inhibitor of histamine methyltransferase (HMT), that can rescue the reg6 vessel branching defects in a dose-dependent manner. Inhibition of HMT by SKF91488 presumably blocks histamine degradation, thus causing histamine accumulation. Consistent with this idea, we found that a high level of histamine also showed significant suppression of reg6 vessel phenotypes. Interestingly, when reg6 adults that had already developed swollen vessel lumina in regenerating fins were treated with histamine or SKF91488, either treatment significantly reduced the number of swollen vessels within 12 h, suggesting a rapid and constant influence of histamine on blood vessel branching. Furthermore, the expression of HMT was significantly elevated in reg6 regenerating fins. Conversely, lowering histamine by administering urocanic acid, a histidine decarboxylase inhibitor, enhanced the reg6 phenotypes. Finally, we identified that the transcription factor, egr-1 (early growth response factor 1), was closely associated with the reg6 phenotype and chemical treatments. Conclusion Taken together, our results suggest that blood vessel branching is influenced by histamine metabolism, possibly through regulating the expression of the egr-1 transcription factor. PMID:18366745

Huang, Cheng-chen; Huang, Chin-Wei; Cheng, Yih-Shyun E; Yu, John

2008-01-01

3

Blood Vessels  

NSDL National Science Digital Library

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 ...

Mrs. Hirschi

2007-11-20

4

Blood Vessel Tension Tester  

NASA Technical Reports Server (NTRS)

In the photo, a medical researcher is using a specially designed laboratory apparatus for measuring blood vessel tension. It was designed by Langley Research Center as a service to researchers of Norfolk General Hospital and Eastern Virginia Medical School, Norfolk, Virginia. The investigators are studying how vascular smooth muscle-muscle in the walls of blood vessels-reacts to various stimulants, such as coffee, tea, alcohol or drugs. They sought help from Langley Research Center in devising a method of measuring the tension in blood vessel segments subjected to various stimuli. The task was complicated by the extremely small size of the specimens to be tested, blood vessel "loops" resembling small rubber bands, some only half a millimeter in diameter. Langley's Instrumentation Development Section responded with a miniaturized system whose key components are a "micropositioner" for stretching a length of blood vessel and a strain gage for measuring the smooth muscle tension developed. The micropositioner is a two-pronged holder. The loop of Mood vessel is hooked over the prongs and it is stretched by increasing the distance between the prongs in minute increments, fractions of a millimeter. At each increase, the tension developed is carefully measured. In some experiments, the holder and specimen are lowered into the test tubes shown, which contain a saline solution simulating body fluid; the effect of the compound on developed tension is then measured. The device has functioned well and the investigators say it has saved several months research time.

1978-01-01

5

Tumor Blood Vessel Dynamics  

NASA Astrophysics Data System (ADS)

``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.

Munn, Lance

2009-11-01

6

HEART AND BLOOD VESSELS CARDIOVASCULARCARDIOVASCULAR  

E-print Network

HEART AND BLOOD VESSELS CARDIOVASCULARCARDIOVASCULAR SYSTEMSYSTEM SYSTEM COMPONENTS · Heart pumps blood though blood vessels where exchanges can take place with the interstitial fluid (between cells) · Heart and blood vessels regulate blood flow according to the needs of the body

Cochran-Stafira, D. Liane

7

Retinal image blood vessel segmentation  

Microsoft Academic Search

The appearance and structure of blood vessels in retinal images play an important role in diagnosis of eye diseases. This paper proposes a method for segmentation of blood vessels in color retinal images. We present a method that uses 2-D Gabor wavelet to enhance the vascular pattern. We locate and segment the blood vessels using adaptive thresholding. The technique is

M. Usman Akram; Anam Tariq; Shoab A. Khan

2009-01-01

8

Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol  

E-print Network

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

Loughry, Jim

9

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

PubMed Central

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

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

2013-01-01

10

Blood Vessels Help Tumors Grow  

NSDL National Science Digital Library

In this video segment, adapted from NOVA, Dr. Judah Folkman uses the scientific method to discover how cancer cells induce the formation of new blood vessels, which in turn nourish those cancer cells.

Foundation, Wgbh E.

2007-04-19

11

Exploring the Elasticity of Blood Vessels  

NSDL National Science Digital Library

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.

2000-07-01

12

Molecular control of endothelial cell behaviour during blood vessel morphogenesis  

Microsoft Academic Search

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 cellcell 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

Shane P. Herbert; Didier Y. R. Stainier

2011-01-01

13

Blood Vessels of the Future  

NSDL National Science Digital Library

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

2011-06-03

14

THE FAKS ABOUT BLOOD VESSEL ASSEMBLY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Potential role of FAK in blood vessel assembly. The process of vessel assembly can be dissected into discernible steps (A), and there is evidence to suggest that FAK is involved throughout. In FAK-/- mutants (B), blood vessel assembly is arrested during tubulogenesis, suggesting that the primary rol...

15

Molecular control of endothelial cell behaviour during blood vessel morphogenesis  

PubMed Central

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 cellcell 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 (such as the vascular endothelial growth factor and Notch pathways) to control endothelial cell behaviour during blood vessel sprouting (angiogenesis). These emerging frameworks controlling angiogenesis provide unique insights into fundamental biological processes common to other systems, such as tissue branching morphogenesis, mechanotransduction and tubulogenesis. PMID:21860391

Herbert, Shane P.; Stainier, Didier Y.R.

2012-01-01

16

Retinal blood vessel segmentation via graph cut  

Microsoft Academic Search

Image analysis is becoming increasingly prominent as a non intrusive diagnosis in modern ophthalmology. Blood vessel morphology is an important indicator for diseases like diabetes, hypertension and retinopathy. This paper presents an automated and unsupervised method for retinal blood vessels segmentation using the graph cut technique. The graph is constructed using a rough segmentation from a pre-processed image together with

Ana G. Salazar-Gonzalez; Yongmin Li; Xiaohui Liu

2010-01-01

17

Designer blood vessels and therapeutic revascularization  

PubMed Central

Inadequate vascular perfusion leads to fatal heart attacks, chronic ulcers, and other serious clinical conditions. The body's capacity to restore vascular perfusion through angiogenesis and arteriogenesis is often impaired by pre-existing disease, and availability of native replacements for nonfunctional arteries is limited in many patients. Thus, recreating blood vessels of various calibres through novel engineering technologies has emerged as a radical option among therapeutic strategies for revascularization. Ranging from artificial, recycled or reassembled natural conduits to sophisticated microdevices, we refer to these as designer blood vessels'. Our common efforts to continuously improve vascular replacement design have provided many clues about our own blood vessels, but nature's ability to create nonthrombogenic, immunocompatible, strong, yet biologically responsive blood vessels remains unparalleled. Just as art reproductions never equal the original masterpiece, designer blood vessels may never attain nature's perfection. Nevertheless, they will provide a valuable option as long as they come close enough and are available to many. PMID:14534146

Berglund, Joseph D; Galis, Zorina S

2003-01-01

18

Tianma Modulates Blood Vessel Tonicity  

PubMed Central

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

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

2012-01-01

19

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

20

Blood Vessels of the Fetal Pig Dissection Anterior Vessels Protocol  

E-print Network

. #12;4. After you have removed the thymus, there may still be considerable connective tissue around is clean out the tissue on each side of the throat. The blood vessels you are looking for are deep in the body cavity here and so the overlying tissue must be removed. The majority of this tissue belongs

Loughry, Jim

21

Trends in Tissue Engineering for Blood Vessels  

PubMed Central

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

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

22

Complete Blood Count and Retinal Vessel Calibers  

PubMed Central

Objective The influence of hematological indices such as complete blood count on microcirculation is poorly understood. Retinal microvasculature can be directly visualized and vessel calibers are associated with a range of ocular and systemic diseases. We examined the association of complete blood count with retinal vessel calibers. Methods Cross-sectional population-based Blue Mountains Eye Study, n?=?3009, aged 49+ years. Complete blood count was measured from fasting blood samples taken at baseline examination, 19924. Retinal arteriolar and venular calibers were measured from digitized retinal photographs using a validated semi-automated computer program. Results All analyses adjusted for age, sex, systolic blood pressure, diabetes, smoking and fellow vessel caliber. Higher hematocrit, white cell count and platelet count were associated with narrower arteriolar caliber (p?=?0.02, 0.03 and 0.001 respectively), while higher hemoglobin, hematocrit, red cell count, white cell count and platelet count were associated with wider venular caliber (p<0.0001 for all). Each quintile increase in hematocrit, white cell count and platelet count was associated with approximately 0.5 m narrower arteriolar caliber; whereas each quintile increase in all of the complete blood count components was associated with approximately 12 m wider venular caliber. Conclusions These associations show that elevated levels of hematological indices can have adverse effects on the microcirculation. PMID:25036459

Liew, Gerald; Wang, Jie Jin; Rochtchina, Elena; Wong, Tien Yin; Mitchell, Paul

2014-01-01

23

Blackworms, Blood Vessel Pulsations and Drug Effects.  

ERIC Educational Resources Information Center

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

Lesiuk, Nalena M.; Drewes, Charles D.

1999-01-01

24

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

PubMed Central

NO has been shown to mediate angiogenesis; however, its role in vessel morphogenesis and maturation is not known. Using intravital microscopy, histological analysis, ?smooth muscle actin and chondroitin sulfate proteoglycan 4 staining, microsensor NO measurements, and an NO synthase (NOS) inhibitor, we found that NO mediates mural cell coverage as well as vessel branching and longitudinal extension but not the circumferential growth of blood vessels in B16 murine melanomas. NO-sensitive fluorescent probe 4,5-diaminofluorescein imaging, NOS immunostaining, and the use of NOS-deficient mice revealed that eNOS in vascular endothelial cells is the predominant source of NO and induces these effects. To further dissect the role of NO in mural cell recruitment and vascular morphogenesis, we performed a series of independent analyses. Transwell and under-agarose migration assays demonstrated that endothelial cellderived NO induces directional migration of mural cell precursors toward endothelial cells. An in vivo tissue-engineered blood vessel model revealed that NO mediates endothelialmural cell interaction prior to vessel perfusion and also induces recruitment of mural cells to angiogenic vessels, vessel branching, and longitudinal extension and subsequent stabilization of the vessels. These data indicate that endothelial cellderived NO induces mural cell recruitment as well as subsequent morphogenesis and stabilization of angiogenic vessels. PMID:15951843

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

2005-01-01

25

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

PubMed

NO has been shown to mediate angiogenesis; however, its role in vessel morphogenesis and maturation is not known. Using intravital microscopy, histological analysis, alpha-smooth muscle actin and chondroitin sulfate proteoglycan 4 staining, microsensor NO measurements, and an NO synthase (NOS) inhibitor, we found that NO mediates mural cell coverage as well as vessel branching and longitudinal extension but not the circumferential growth of blood vessels in B16 murine melanomas. NO-sensitive fluorescent probe 4,5-diaminofluorescein imaging, NOS immunostaining, and the use of NOS-deficient mice revealed that eNOS in vascular endothelial cells is the predominant source of NO and induces these effects. To further dissect the role of NO in mural cell recruitment and vascular morphogenesis, we performed a series of independent analyses. Transwell and under-agarose migration assays demonstrated that endothelial cell-derived NO induces directional migration of mural cell precursors toward endothelial cells. An in vivo tissue-engineered blood vessel model revealed that NO mediates endothelial-mural cell interaction prior to vessel perfusion and also induces recruitment of mural cells to angiogenic vessels, vessel branching, and longitudinal extension and subsequent stabilization of the vessels. These data indicate that endothelial cell-derived NO induces mural cell recruitment as well as subsequent morphogenesis and stabilization of angiogenic vessels. PMID:15951843

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

2005-07-01

26

Microvascular Branching as a Determinant of Blood Flow by Intravital Particle Imaging Velocimetry  

NASA Technical Reports Server (NTRS)

The effects of microvascular branching on blood flow were investigated in vivo by microscopic particle imaging velocimetry (micro-PIV). We use micro-PIV to measure blood flow by tracking red blood cells (RBC) as the moving particles. Velocity flow fields, including flow pulsatility, were analyzed for the first four branching orders of capillaries, postcapillary venules and small veins of the microvascular network within the developing avian yolksac at embryonic day 5 (E5). Increasing volumetric flowrates were obtained from parabolic laminar flow profiles as a function of increasing vessel diameter and branching order. Maximum flow velocities increased approximately twenty-fold as the function of increasing vessel diameter and branching order compared to flow velocities of 100 - 150 micron/sec in the capillaries. Results from our study will be useful for the increased understanding of blood flow within anastomotic, heterogeneous microvascular networks.

Parsons-Wingerter, Patricia; McKay, Terri L.; Vickerman, Mary B.; Wernet, Mark P.; Myers, Jerry G.; Radhakrishnan, Krishnan

2007-01-01

27

Zinc oxide nanoflowers make new blood vessels  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

28

A probe for blood-vessel and spinal interiors  

NASA Technical Reports Server (NTRS)

Probe design allows insertion into lumen of blood vessels to perform oximetry and investigate plaque on interior vessel walls. Probe is more accurate than standard oximetry procedures of determining oxygenation of circulating blood.

Frazer, R. E.

1978-01-01

29

Retinal images: Blood vessel segmentation by threshold probing  

Microsoft Academic Search

An automated system for screening and diagnosis of diabetic retinopathy should segment blood vessels from colored retinal image to assist the ophthalmologists. We present a method for blood vessel enhancement and segmentation. This paper proposes a wavelet based method for vessel enhancement, piecewise threshold probing and adaptive thresholding for vessel localization and segmentation respectively. The method is tested on publicly

M. Usman Akram; Aasia Khanum

2010-01-01

30

RETINAL BLOOD VESSEL SEGMENTATION USING GEODESIC VOTING METHODS Youssef Rouchdy  

E-print Network

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

Cohen, Laurent

31

Vulnerability of xylem vessels to cavitation in sugar maple. Scaling from individual vessels to whole branches.  

PubMed

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

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

2003-04-01

32

Perivascular cells in blood vessel regeneration  

PubMed Central

Vascular engineering seeks to design and construct functional blood vessels comprising endothelial cells and perivascular cells (PCs), with the ultimate goal of clinical translation. While endothelial behavior has been extensively investigated, PCs play an equally significant role in the development of novel regenerative strategies, providing functionality and stability to vessels. The two major classes of PCs are vascular smooth muscle cells (vSMCs) and pericytes; vSMCs can be further sub-classified as either contractile or synthetic. The inclusion of these cell types is crucial for successful regeneration of blood vessels. Furthermore, understanding distinctions between vSMCs and pericytes will enable improved therapeutics in a tissue-specific manner. Here we focus on the approaches and challenges facing the use of PCs in vascular regeneration, including their characteristics, stem cell sources, and interactions with endothelial cells. Finally, we discuss biochemical and microRNA (miR) regulators of PC behavior and engineering approaches that mimic various cues affecting PC function. PMID:23554249

Wanjare, Maureen; Kusuma, Sravanti; Gerecht, Sharon

2013-01-01

33

Method and device for supporting blood vessels during anastomosis  

DOEpatents

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

Doss, J.D.

1985-05-20

34

Photoacoustic removal of occlusions from blood vessels  

DOEpatents

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

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

2002-01-01

35

On the Adaptive Detection of Blood Vessels in Retinal Images  

Microsoft Academic Search

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

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

2006-01-01

36

Blood Vessel Enhancement and Segmentation Using Wavelet Transform  

Microsoft Academic Search

Retinal vessel segmentation is an essential step for the diagnoses of various eye diseases. An automated tool for blood vessel segmentation is useful to eye specialists for purpose of patient screening and clinical study. Vascular pattern is normally not visible in retinal images. In this paper, we present a method for enhancing, locating and segmenting blood vessels in images of

M. Usman Akram; A. Atzaz; S. F. Aneeque; Shoab A. Khan

2009-01-01

37

On the adaptive detection of blood vessels in retinal images  

Microsoft Academic Search

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

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

2006-01-01

38

Application of Computational Physics: Blood Vessel Constrictions and Medical Infuses  

E-print Network

Application of computation in many fields are growing fast in last two decades. Increasing on computation performance helps researchers to understand natural phenomena in many fields of science and technology including in life sciences. Computational fluid dynamic is one of numerical methods which is very popular used to describe those phenomena. In this paper we propose moving particle semi-implicit (MPS) and molecular dynamics (MD) to describe different phenomena in blood vessel. The effect of increasing the blood pressure on vessel wall will be calculate using MD methods, while the two fluid blending dynamics will be discussed using MPS. Result from the first phenomenon shows that around 80% of constriction on blood vessel make blood vessel increase and will start to leak on vessel wall, while from the second phenomenon the result shows the visualization of two fluids mixture (drugs and blood) influenced by ratio of drugs debit to blood debit. Keywords: molecular dynamic, blood vessel, fluid dynamic, movin...

Suprijadi,; Subekti, Petrus; Viridi, Sparisoma

2013-01-01

39

Application of Computational Physics: Blood Vessel Constrictions and Medical Infuses  

E-print Network

Application of computation in many fields are growing fast in last two decades. Increasing on computation performance helps researchers to understand natural phenomena in many fields of science and technology including in life sciences. Computational fluid dynamic is one of numerical methods which is very popular used to describe those phenomena. In this paper we propose moving particle semi-implicit (MPS) and molecular dynamics (MD) to describe different phenomena in blood vessel. The effect of increasing the blood pressure on vessel wall will be calculate using MD methods, while the two fluid blending dynamics will be discussed using MPS. Result from the first phenomenon shows that around 80% of constriction on blood vessel make blood vessel increase and will start to leak on vessel wall, while from the second phenomenon the result shows the visualization of two fluids mixture (drugs and blood) influenced by ratio of drugs debit to blood debit. Keywords: molecular dynamic, blood vessel, fluid dynamic, moving particle semi implicit.

Suprijadi; Mohamad Rendi; Petrus Subekti; Sparisoma Viridi

2013-12-14

40

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

PubMed

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

Wlchli, Thomas; Mateos, Jos Mara; Weinman, Oliver; Babic, Daniela; Regli, Luca; Hoerstrup, Simon P; Gerhardt, Holger; Schwab, Martin E; Vogel, Johannes

2015-01-01

41

Quantitative analysis of blood vessel geometry  

NASA Astrophysics Data System (ADS)

Re-narrowing or restenosis of a human coronary artery occurs within six months in one third of balloon angioplasty procedures. Accurate and repeatable quantitative analysis of vessel shape is important to characterize the progression and type of restenosis, and to evaluate effects new therapies might have. A combination of complicated geometry and image variability, and the need for high resolution and large image size makes visual/manual analysis slow, difficult, and prone to error. The image processing and analysis described here was developed to automate feature extraction of the lumen, internal elastic lamina, neointima, external elastic lamina, and tunica adventitia and to enable an objective, quantitative definition of blood vessel geometry. The quantitative geometrical analysis enables the measurement of several features including perimeter, area, and other metrics of vessel damage. Automation of feature extraction creates a high throughput capability that enables analysis of serial sections for more accurate measurement of restenosis dimensions. Measurement results are input into a relational database where they can be statistically analyzed compared across studies. As part of the integrated process, results are also imprinted on the images themselves to facilitate auditing of the results. The analysis is fast, repeatable and accurate while allowing the pathologist to control the measurement process.

Fuhrman, Michael G.; Abdul-Karim, Othman; Shah, Sujal; Gilbert, Steven G.; Van Bibber, Richard

2001-07-01

42

Simulation of Blood Flow at Vessel Bifurcation by Lattice Boltzmann Method  

NASA Astrophysics Data System (ADS)

The application of the lattice Boltzmann method to the large vessel bifurcation blood flow is investigated in a wide range of Reynolds numbers. The velocity, shear stress and pressure distributions at the bifurcation are presented in detail. The flow separation zones revealed with increase of Reynolds number are located in the areas of the daughter branches distal to the outer corners of the bifurcation where some deposition of particular blood components might occur to form arteriosclerosis. The results also demonstrate that the lattice Boltzmann method is adaptive to simulating the flow in larger vessels under a high Reynolds number.

Kang, Xiu-Ying; Liu, Da-He; Zhou, Jing; Jin, Yong-Juan

2005-11-01

43

Bridging mucosal vessels associated with rhythmically oscillating blood flow in murine colitis.  

PubMed

Oscillatory blood flow in the microcirculation is generally considered to be the result of cardiopulmonary influences or active vasomotion. In this report, we describe rhythmically oscillating blood flow in the bridging vessels of the mouse colon that appeared to be independent of known biological control mechanisms. Corrosion casting and scanning electron microscopy of the mouse colon demonstrated highly branched bridging vessels that connected the submucosal vessels with the mucosal plexus. Because of similar morphometric characteristics (19 +/- 11 microm vs. 28 +/- 16 microm), bridging arterioles and venules were distinguished by tracking fluorescent nanoparticles through the microcirculation using intravital fluorescence videomicroscopy. In control mice, the blood flow through the bridging vessels was typically continuous and unidirectional. In contrast, two models of chemically induced inflammation (trinitrobenzenesulfonic acid and dextran sodium sulfate) were associated with a twofold reduction in flow velocity and the prominence of rhythmically oscillating blood flow. The blood oscillation was characterized by tracking the bidirectional displacement of fluorescent nanoparticles. Space-time plots and particle tracking of the oscillating segments demonstrated an oscillation frequency between 0.2 and 5.1 cycles per second. Discrete Fourier transforms demonstrated a power spectrum composed of several base frequencies. These observations suggest that inflammation-inducible changes in blood flow patterns in the murine colon resulted in both reduced blood flow velocity and rhythmic oscillations within the bridging vessels of the mouse colon. PMID:18085623

Turhan, Aslihan; Konerding, Moritz A; Tsuda, Akira; Ravnic, Dino J; Hanidziar, Dusan; Lin, Miao; Mentzer, Steven J

2008-01-01

44

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

SciTech Connect

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.

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

45

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

SciTech Connect

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.

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

1991-05-01

46

Pattern of blood vessels in eyes with coloboma  

PubMed Central

Background: Choroidal coloboma, especially with optic disc involvement affects the blood vessel (BV) pattern in the fundus. Aim: The aim of this study was to report the observations on the pattern of retinal BVs in eyes with fundus coloboma. Design: Retrospective observational study. Materials and Methods: Twenty four eyes of 19 patients with fundus coloboma and the disc involvement in the coloboma was classified according to a previous publication. Results: Four varieties of BVs were identified in the area of coloboma - BVs that were continuous with those arising from the optic disc; vessels emanating from the floor of coloboma whose continuity with central retinal artery or its branches could be indirectly established; and those emanating from the floor of coloboma whose continuity with central retinal artery could not be established. In addition, extraocular BVs were visible through the thinned sclera. The retinal BVs often traversed the coloboma to reach the normal retina. The disc itself was found to be small and had no physiological cup (if not colobomatous). Conclusions: One should be aware of the major BVs transgressing the coloboma while performing relaxing cuts in the intercalary membrane, during the surgery for retinal detachments in eyes with coloboma. Physiological cup is usually absent (when the disc is not colobomatous). Hence, any cupping in such eyes should be viewed with suspicion. PMID:24413826

Lingam, Gopal

2013-01-01

47

Perivascular microglia promote blood vessel disintegration in the ischemic penumbra.  

PubMed

The contribution of microglia to ischemic cortical stroke is of particular therapeutic interest because of the impact on the survival of brain tissue in the ischemic penumbra, a region that is potentially salvable upon a brain infarct. Whether or not tissue in the penumbra survives critically depends on blood flow and vessel perfusion. To study the role of microglia in cortical stroke and blood vessel stability, CX3CR1(+/GFP) mice were subjected to transient middle cerebral artery occlusion and then microglia were investigated using time-lapse two-photon microscopy in vivo. Soon after reperfusion, microglia became activated in the stroke penumbra and started to expand cellular protrusions towards adjacent blood vessels. All microglia in the penumbra were found associated with blood vessels within 24h post reperfusion and partially fully engulfed them. In the same time frame blood vessels became permissive for blood serum components. Migration assays in vitro showed that blood serum proteins leaking into the tissue provided molecular cues leading to the recruitment of microglia to blood vessels and to their activation. Subsequently, these perivascular microglia started to eat up endothelial cells by phagocytosis, which caused an activation of the local endothelium and contributed to the disintegration of blood vessels with an eventual break down of the blood brain barrier. Loss-of-microglia-function studies using CX3CR1(GFP/GFP) mice displayed a decrease in stroke size and a reduction in the extravasation of contrast agent into the brain penumbra as measured by MRI. Potentially, medication directed at inhibiting microglia activation within the first day after stroke could stabilize blood vessels in the penumbra, increase blood flow, and serve as a valuable treatment for patients suffering from ischemic stroke. PMID:25500713

Jolivel, Valrie; Bicker, Frank; Binam, Fabien; Ploen, Robert; Keller, Stefanie; Gollan, Ren; Jurek, Betty; Birkenstock, Jrme; Poisa-Beiro, Laura; Bruttger, Julia; Opitz, Verena; Thal, Serge C; Waisman, Ari; Buerle, Tobias; Schfer, Michael K; Zipp, Frauke; Schmidt, Mirko H H

2015-02-01

48

Instability and "Sausage-String" Appearance in Blood Vessels during High Blood Pressure  

E-print Network

A new Rayleigh-type instability is proposed to explain the `sausage-string' pattern of alternating constrictions and dilatations formed in blood vessels under influence of a vasoconstricting agent. Our theory involves the nonlinear elasticity characteristics of the vessel wall, and provides predictions for the conditions under which the cylindrical form of a blood vessel becomes unstable.

Alstrm, P; Colding-Jorgensen, M; Gustafsson, F; Holstein-Rathlou, N H; Alstrom, Preben; Eguiluz, Victor M.; Colding-Jorgensen, Morten; Gustafsson, Finn; Holstein-Rathlou, Niels-Henrik

1999-01-01

49

Large Blood Vessels 1.1 Introduction --The Cardiovascular System  

E-print Network

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

Luo, Xiaoyu

50

Segmentation of retinal blood vessels using the radial projection and semi-supervised approach  

Microsoft Academic Search

Automatic segmentation of retinal blood vessels has become a necessary diagnostic procedure in ophthalmology. The blood vessels consist of two types of vessels, i.e., thin vessels and wide vessels. Therefore, a segmentation method may require two different processes to treat different vessels. However, traditional segmentation algorithms hardly draw a distinction between thin and wide vessels, but deal with them together.

Xinge You; Qinmu Peng; Yuan Yuan; Yiu-ming Cheung; Jiajia Lei

2011-01-01

51

Detection of Retinal Blood Vessels Based on Nonlinear Projections  

Microsoft Academic Search

An automated method for blood vessel segmentation is presented in this paper. The approach uses the nonlinear orthogonal projection\\u000a to capture the features of vessel networks, and derives a novel local adaptive thresholding algorithm for vessel detection.\\u000a By embedding in a kind of image decomposition model, the selection of system parameter which reflects the size of concerned\\u000a convex set is

Yongping Zhang; Wynne Hsu; Mong-li Lee

2009-01-01

52

Computer Analysis of Eye Blood-Vessel Images  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

53

Effects of hypoxia on vertebrate blood vessels.  

PubMed

Hypoxia contracts mammalian respiratory vessels and increases vascular resistance in respiratory tissues of many vertebrates. In systemic vessels these responses vary, hypoxia relaxes mammalian vessels and contracts systemic arteries from cyclostomes. It has been proposed that hypoxic vasoconstriction in cyclostome systemic arteries is the antecedent to mammalian hypoxic pulmonary vasoconstriction, however, phylogenetic characterization of hypoxic responses is lacking. In this study, we characterized the hypoxic response of isolated systemic and respiratory vessels from a variety of vertebrates using standard myography. Pre-gill/respiratory (ventral aorta, afferent branchial artery, pulmonary artery) and post-gill/systemic (dorsal and thoracic aortas, efferent branchial artery) from lamprey (Petromyzon marinus), sandbar shark (Carcharhinus plumbeus), yellowfin tuna (Thunnus albacares), American bullfrog (Rana catesbeiana), American alligator (Alligator mississippiensis), Pekin duck (Anas platyrhynchos domesticus), chicken (Gallus domesticus) and rat (Rattus norvegicus) were exposed to hypoxia at rest or during pre-stimulation (elevated extracellular potassium, epinephrine or norepinephrine). Hypoxia produced a relaxation or transient contraction followed by relaxation in all pre-gill vessels, except for contraction in lamprey, and vasoconstriction or tri-phasic constriction-dilation-constriction in all pulmonary vessels. Hypoxia contracted systemic vessels from all animals except shark and rat and in pre-contracted rat aortas it produced a transient contraction followed by relaxation. These results show that while the classic "systemic hypoxic vasodilation and pulmonary hypoxic vasoconstriction" may occur in the microcirculation, the hypoxic response of the vertebrate macrocirculation is quite variable. These findings also suggest that hypoxic vasoconstriction is a phylogenetically ancient response. PMID:18214862

Russell, Michael J; Dombkowski, Ryan A; Olson, Kenneth R

2008-03-01

54

Detection of Blood Vessels in the Retina Using Gabor Filters  

Microsoft Academic Search

Quantitative analysis of the vascular architecture of the retina as well as changes in the shape, width, and tortuosity of the vessels could assist in the monitoring of the effects of diabetes, arteriosclerosis, hypertension, and premature birth on the visual system. The detection of blood vessels in the retina is an important initial step for most applications of image analysis

Rangaraj M. Rangayyan; Faraz Oloumi; P. Eshghzadeh-Zanjani; F. J. Ayres

2007-01-01

55

A novel method for blood vessel detection from retinal images  

PubMed Central

Background The morphological changes of the retinal blood vessels in retinal images are important indicators for diseases like diabetes, hypertension and glaucoma. Thus the accurate segmentation of blood vessel is of diagnostic value. Methods In this paper, we present a novel method to segment retinal blood vessels to overcome the variations in contrast of large and thin vessels. This method uses adaptive local thresholding to produce a binary image then extract large connected components as large vessels. The residual fragments in the binary image including some thin vessel segments (or pixels), are classified by Support Vector Machine (SVM). The tracking growth is applied to the thin vessel segments to form the whole vascular network. Results The proposed algorithm is tested on DRIVE database, and the average sensitivity is over 77% while the average accuracy reaches 93.2%. Conclusions In this paper, we distinguish large vessels by adaptive local thresholding for their good contrast. Then identify some thin vessel segments with bad contrast by SVM, which can be lengthened by tracking. This proposed method can avoid heavy computation and manual intervention. PMID:20187975

2010-01-01

56

A completely biological tissue-engineered human blood vessel  

Microsoft Academic Search

Mechanically challenged tissue-engi- neered organs, such as blood vessels, traditionally re- lied on synthetic or modified biological materials for structural support. In this report, we present a novel approach to tissue-engineered blood vessel (TEBV) production that is based exclusively on the use of cul- tured human cells, i.e., without any synthetic or ex- ogenous biomaterials. Human vascular smooth muscle cells

STEPHANIE PAQUET; RAYMOND LABBE; LUCIE GERMAIN; FRANCOIS A. AUGER

57

Analysis of Blood Flow in a Partially Blocked Bifurcated Blood Vessel  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

58

Aging changes in the heart and blood vessels  

MedlinePLUS

... the heart (aorta) becomes thicker, stiffer, and less flexible. This is probably related to changes in the connective tissue of the blood vessel wall. This makes the blood pressure higher and makes the heart work harder, which may lead to thickening of the ...

59

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

PubMed Central

Background A clear understanding of the blood vessels in the eye is helpful in the diagnosis and treatment of ophthalmic diseases, such as glaucoma. Conventional techniques such as micro-CT imaging and histology are not sufficiently accurate to identify the vessels in the eye, because their diameter is just a few microns. The newly developed medical imaging technology, X-ray phase-contrast imaging (XPCI), is able to distinguish the structure of the vessels in the eye. In this study, XPCI was used to identify the internal structure of the blood vessels in the eye. Methods After injection with barium sulfate via the ear border artery, an anesthetized rabbit was killed and its eye was fixed in vitro in 10% formalin solution. We acquired images using XPCI at the Shanghai Synchrotron Radiation Facility. The datasets were converted into slices by filtered back-projection (FBP). An angiographic score was obtained as a parameter to quantify the density of the blood vessels. A three-dimensional (3D) model of the blood vessels was then established using Amira 5.2 software. Results With XPCI, blood vessels in the rabbit eye as small as 18?m in diameter and a sixth of the long posterior ciliary artery could be clearly distinguished. In the 3D model, we obtained the level 4 branch structure of vessels in the fundus. The diameters of the arteria centralis retinae and its branches are about 200?m, 110?m, 95?m, 80?m and 40?m. The diameters of the circulus arteriosus iridis major and its branches are about 210?m, 70?m and 30?m. Analysis of vessel density using the angiographic score showed that the blood vessels had maximum density in the fundus and minimum density in the area anterior to the equator (scores 0.27??0.029 and 0.16??0.032, respectively). We performed quantitative angiographic analysis of the blood vessels to further investigate the density of the vessels. Conclusions XPCI provided a feasible means to determine the structure of the blood vessels in the eye. We were able to determine the diameters and morphological characteristics of the vessels from both 2D images and the 3D model. By analyzing the images, we obtained measurements of the density distribution of the microvasculature, and this approach may provide valuable reference information prior to glaucoma filtration surgery. PMID:23577753

2013-01-01

60

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

NASA Astrophysics Data System (ADS)

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

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

2008-10-01

61

Integration of Repulsive Guidance Cues Generates Avascular Zones that Shape Mammalian Blood Vessels  

PubMed Central

Rationale Positive signals, such as vascular endothelial factor (VEGF), direct endothelial cells (ECs) to specific locations during blood vessel formation. Less is known about repulsive signal contribution to shaping vessels. Recently, neuronal guidance cues (NGCs) have been shown to influence EC behavior, particularly in directing sprouting angiogenesis by repelling ECs. However, their role during de novo blood vessel formation remains unexplored. Objective To identify signals that guide and pattern the first mammalian blood vessels. Methods and Results Using genetic mouse models, we show that blood vessels are sculpted via the generation of stereotyped avascular zones by EC-repulsive cues. We demonstrate that Semaphorin3E (Sema3E) is a key factor that shapes the paired DA in mouse, as sema3E-/- embryos develop an abnormally branched aortic plexus with a markedly narrowed avascular midline. In vitro cultures and avian grafting experiments show strong repulsion of ECs by Sema3E-expressing cells. We further identify the mouse notochord as a rich source of multiple redundant NGCs. Mouse embryos that lack notochords fail to form cohesive aortic vessels due to loss of the avascular midline, yet maintain lateral avascular zones. We demonstrate that lateral avascular zones are directly generated by the lateral plate mesoderm (LPM), a critical source of Sema3E. Conclusions These findings demonstrate that Sema3E-generated avascular zones are critical regulators of mammalian cardiovascular patterning, and are the first to identify a repulsive role for the LPM. Integration of multiple, and in some cases redundant, repulsive cues from various tissues is critical to patterning the first embryonic blood vessels. PMID:22076636

Meadows, Stryder M.; Fletcher, Peter J.; Moran, Carlos; Xu, Ke; Neufeld, Gera; Chauvet, Sophie; Mann, Fanny; Krieg, Paul; Cleaver, Ondine

2011-01-01

62

Blood Vessel Adaptation with Fluctuations in Capillary Flow Distribution  

PubMed Central

Throughout the life of animals and human beings, blood vessel systems are continuously adapting their structures the diameter of vessel lumina, the thickness of vessel walls, and the number of micro-vessels to meet the changing metabolic demand of the tissue. The competition between an ever decreasing tendency of luminal diameters and an increasing stimulus from the wall shear stress plays a key role in the adaptation of luminal diameters. However, it has been shown in previous studies that the adaptation dynamics based only on these two effects is unstable. In this work, we propose a minimal adaptation model of vessel luminal diameters, in which we take into account the effects of metabolic flow regulation in addition to wall shear stresses and the decreasing tendency of luminal diameters. In particular, we study the role, in the adaptation process, of fluctuations in capillary flow distribution which is an important means of metabolic flow regulation. The fluctuation in the flow of a capillary group is idealized as a switch between two states, i.e., an open-state and a close-state. Using this model, we show that the adaptation of blood vessel system driven by wall shear stress can be efficiently stabilized when the open time ratio responds sensitively to capillary flows. As micro-vessel rarefaction is observed in our simulations with a uniformly decreased open time ratio of capillary flows, our results point to a possible origin of micro-vessel rarefaction, which is believed to induce hypertension. PMID:23029014

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

2012-01-01

63

Brain blood vessel segmentation using line-shaped profiles  

NASA Astrophysics Data System (ADS)

Segmentation of cerebral blood vessels is of great importance in diagnostic and clinical applications, especially for embolization of cerebral aneurysms and arteriovenous malformations (AVMs). In order to perform embolization of the AVM, the structural and geometric information of blood vessels from 3D images is of utmost importance. For this reason, the in-depth segmentation of cerebral blood vessels is usually done as a fusion of different segmentation techniques, often requiring extensive user interaction. In this paper we introduce the idea of line-shaped profiling with an application to brain blood vessel and AVM segmentation, efficient both in terms of resolving details and in terms of computation time. Our method takes into account both local proximate and wider neighbourhood of the processed pixel, which makes it efficient for segmenting large blood vessel tree structures, as well as fine structures of the AVMs. Another advantage of our method is that it requires selection of only one parameter to perform segmentation, yielding very little user interaction.

Babin, Danilo; Piurica, Aleksandra; De Vylder, Jonas; Vansteenkiste, Ewout; Philips, Wilfried

2013-11-01

64

What Determines Blood Vessel Structure? Genetic Prespecification vs. Hemodynamics  

NSDL National Science Digital Library

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

Elizabeth A. V. Jones (College de France)

2006-10-01

65

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

PubMed Central

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% = 1.62.4 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

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

2003-01-01

66

Tissue engineering: creation of long-lasting blood vessels.  

PubMed

The construction of stable blood vessels is a fundamental challenge for tissue engineering in regenerative medicine. Although certain genes can be introduced into vascular cells to enhance their survival and proliferation, these manipulations may be oncogenic. We show here that a network of long-lasting blood vessels can be formed in mice by co-implantation of vascular endothelial cells and mesenchymal precursor cells, by-passing the need for risky genetic manipulations. These networks are stable and functional for one year in vivo. PMID:15014486

Koike, Naoto; Fukumura, Dai; Gralla, Oliver; Au, Patrick; Schechner, Jeffrey S; Jain, Rakesh K

2004-03-11

67

Acrolein generation stimulates hypercontraction in isolated human blood vessels  

PubMed Central

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertensionall conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H2O2 exposure (1 ?M1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 ?M), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca2+ to hypercontraction. Acrolein or allylamine but not H2O2, benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca2+-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in SpragueDawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension. PMID:17095030

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

2012-01-01

68

Unusual metastases of thyroid cancer to mediastinal blood vessels.  

PubMed

Poorly differentiated thyroid cancer is a rare thyroid cancer, accounts for approximately 5% of all thyroid cancer cases, and is associated with a poor prognosis. It commonly metastasizes to regional lymph nodes, lung, and bones. We present a patient with poorly differentiated thyroid cancer with unusual extensive spread to mediastinal blood vessels. PMID:24561690

Ma, Hong Yun; Moadel, Renee; Freeman, Leonard M

2015-01-01

69

Fractal structures in stenoses and aneurysms in blood vessels  

PubMed Central

Recent advances in the field of chaotic advection provide the impetus to revisit the dynamics of particles transported by blood flow in the presence of vessel wall irregularities. The irregularity, being either a narrowing or expansion of the vessel, mimicking stenoses or aneurysms, generates abnormal flow patterns that lead to a peculiar filamentary distribution of advected particles, which, in the blood, would include platelets. Using a simple model, we show how the filamentary distribution depends on the size of the vessel wall irregularity, and how it varies under resting or exercise conditions. The particles transported by blood flow that spend a long time around a disturbance either stick to the vessel wall or reside on fractal filaments. We show that the faster flow associated with exercise creates widespread filaments where particles can get trapped for a longer time, thus allowing for the possible activation of such particles. We argue, based on previous results in the field of active processes in flows, that the non-trivial long-time distribution of transported particles has the potential to have major effects on biochemical processes occurring in blood flow, including the activation and deposition of platelets. One aspect of the generality of our approach is that it also applies to other relevant biological processes, an example being the coexistence of plankton species investigated previously. PMID:21078637

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

2010-01-01

70

Enhanced Cytomegalovirus Infection in Atherosclerotic Human Blood Vessels  

Microsoft Academic Search

Human cytomegalovirus (CMV) is a possible co-factor in atherogenesis and vascular occlusion, but its abil- ity 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

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

2004-01-01

71

Image Segmentation Methods for Detecting Blood Vessels in Angiography  

E-print Network

Image Segmentation Methods for Detecting Blood Vessels in Angiography Albert C. S. Chung Lo Kwee and embolization. In this article, I give an overview of the image segmentation methods using the features and mortality worldwide. Therefore, developing reliable and robust image segmentation methods for angiography

Chung, Albert C. S.

72

Gene Expression Analysis in Human Breast Cancer Associated Blood Vessels  

PubMed Central

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 (572 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

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

73

Enhanced Cytomegalovirus Infection in Atherosclerotic Human Blood Vessels  

PubMed Central

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

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

74

Enhanced cytomegalovirus infection in atherosclerotic human blood vessels.  

PubMed

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

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

2004-02-01

75

STUDIES ON THE BLOOD VESSELS IN THE MEMBRANES OF CHICK EMBRYOS  

PubMed Central

A comparison of the effect of stimulation upon the arterial subdivisions shows that these differ in irritability. The capillaries are most irritable, then come the small arterial branches, and last the main stems of arteries, these being the least irritable. The non-innervated blood vessels of the vascular membranes exhibit therefore the behavior described by G. Ricker in the case of those which have a nervous apparatus. We have demonstrated accordingly similar properties in vessels which are not innervated as in those which are. Certain differences exist however. The action of adrenalin on the vessels of the vascular membrane is inconstant and certain other substances are wholly ineffective. Ricker's experiments have advanced knowledge on the regularity of the vascular reactions and have paved the way for these experiments of ours. The result of our experiments with vessels free of nerves suggests that a reexamination may be fruitful of the mechanism which obtains in innervated vessels. There can be no doubt that nerves play a rle in the behavior of vessels; it appears now to be necessary to define more accurately precisely what this is. PMID:19869751

Lange, Fritz

1930-01-01

76

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

PubMed

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

Bisaillon, A

1981-01-01

77

Melanopsin mediates light-dependent relaxation in blood vessels.  

PubMed

Melanopsin (opsin4; Opn4), a non-image-forming opsin, has been linked to a number of behavioral responses to light, including circadian photo-entrainment, light suppression of activity in nocturnal animals, and alertness in diurnal animals. We report a physiological role for Opn4 in regulating blood vessel function, particularly in the context of photorelaxation. Using PCR, we demonstrate that Opn4 (a classic G protein-coupled receptor) is expressed in blood vessels. Force-tension myography demonstrates that vessels from Opn4(-/-) mice fail to display photorelaxation, which is also inhibited by an Opn4-specific small-molecule inhibitor. The vasorelaxation is wavelength-specific, with a maximal response at ?430-460 nm. Photorelaxation does not involve endothelial-, nitric oxide-, carbon monoxide-, or cytochrome p450-derived vasoactive prostanoid signaling but is associated with vascular hyperpolarization, as shown by intracellular membrane potential measurements. Signaling is both soluble guanylyl cyclase- and phosphodiesterase 6-dependent but protein kinase G-independent. ?-Adrenergic receptor kinase 1 (?ARK 1 or GRK2) mediates desensitization of photorelaxation, which is greatly reduced by GRK2 inhibitors. Blue light (455 nM) regulates tail artery vasoreactivity ex vivo and tail blood blood flow in vivo, supporting a potential physiological role for this signaling system. This endogenous opsin-mediated, light-activated molecular switch for vasorelaxation might be harnessed for therapy in diseases in which altered vasoreactivity is a significant pathophysiologic contributor. PMID:25404319

Sikka, Gautam; Hussmann, G Patrick; Pandey, Deepesh; Cao, Suyi; Hori, Daijiro; Park, Jong Taek; Steppan, Jochen; Kim, Jae Hyung; Barodka, Viachaslau; Myers, Allen C; Santhanam, Lakshmi; Nyhan, Daniel; Halushka, Marc K; Koehler, Raymond C; Snyder, Solomon H; Shimoda, Larissa A; Berkowitz, Dan E

2014-12-16

78

Tumor Endothelial Marker 8 Amplifies Canonical Wnt Signaling in Blood Vessels  

PubMed Central

Tumor Endothelial Marker 8/Anthrax Toxin Receptor 1 (TEM8/ANTXR1) expression is induced in the vascular compartment of multiple tumors and therefore, is a candidate molecule to target tumor therapies. This cell surface molecule mediates anthrax toxin internalization, however, its physiological function in blood vessels remains largely unknown. We identified the chicken chorioallantoic membrane (CAM) as a model system to study the endogenous function of TEM8 in blood vessels as we found that TEM8 expression was induced transiently between day 10 and 12 of embryonic development, when the vascular tree is undergoing final development and growth. We used the cell-binding component of anthrax toxin, Protective Antigen (PA), to engage endogenous TEM8 receptors and evaluate the effects of PA-TEM8 complexes on vascular development. PA applied at the time of highest TEM8 expression reduced vascular density and disrupted hierarchical branching as revealed by quantitative morphometric analysis of the vascular tree after 48h. PA-dependent reduced branching phenotype was partially mimicked by Wnt3a application and ameliorated by the Wnt antagonist, Dikkopf-1. These results implicate TEM8 expression in endothelial cells in regulating the canonical Wnt signaling pathway at this day of CAM development. Consistent with this model, PA increased beta catenin levels acutely in CAM blood vessels in vivo and in TEM8 transfected primary human endothelial cells in vitro. TEM8 expression in Hek293 cells, which neither express endogenous PA-binding receptors nor Wnt ligands, stabilized beta catenin levels and amplified beta catenin-dependent transcriptional activity induced by Wnt3a. This agonistic function is supported by findings in the CAM, where the increase in TEM8 expression from day 10 to day 12 and PA application correlated with Axin 2 induction, a universal reporter gene for canonical Wnt signaling. We postulate that the developmentally controlled expression of TEM8 modulates endothelial cell response to canonical Wnt signaling to regulate vessel patterning and density. PMID:21829615

Verma, Kiran; Gu, Jingsheng; Werner, Erica

2011-01-01

79

Optical-resolution photoacoustic microscopy for imaging blood vessels in vivo  

NASA Astrophysics Data System (ADS)

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

Yuan, Yi

2012-12-01

80

Control of Blood Vessel Identity: From Embryo to Adult  

PubMed Central

Arteries and veins have been historically defined by the direction of blood flow and oxygen tension within the vessel, in addition to their functional, hemodynamic, and anatomical differences. It is now known that the molecular identity of these vessels is genetically predetermined, with specific molecular pathways activated during the development of arteries and veins. Eph-B4 is a determinant of venous differentiation and Ephrin-B2 is a determinant of arterial differentiation. Placement of a vein into the higher pressure and flow of the arterial circulation results in adaptation of the vein to the arterial environment. There is selective loss of Eph-B4 expression without induction of Ephrin-B2 expression during vein graft adaptation. These findings suggest that loss of venous identity is the crucial mechanism in vein graft adaptation and that developmentally critical determinants of vessel identity are plastic during adult life. PMID:23555335

2008-01-01

81

Investigation on artificial blood vessels prepared from bacterial cellulose.  

PubMed

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 100mm, 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

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

2015-01-01

82

Regulation of blood vessels by prolactin and vasoinhibins.  

PubMed

Prolactin (PRL) stimulates the growth of new blood vessels (angiogenesis) either directly through actions on endothelial cells or indirectly by upregulating proangiogenic factors like vascular endothelial growth factor (VEGF). Moreover, PRL acquires antiangiogenic properties after undergoing proteolytic cleavage to vasoinhibins, a family of PRL fragments (including 16kDa PRL) with potent antiangiogenic, vasoconstrictive, and antivasopermeability effects. In view of the opposing actions of PRL and vasoinhibins, the regulation of the proteases responsible for specific PRL cleavage represents an efficient mechanism for controlling blood vessel growth and function. This review briefly describes the vascular actions of PRL and vasoinhibins, and addresses how their interplay could help drive biological effects of PRL in the context of health and disease. PMID:25472535

Clapp, Carmen; Thebault, Stphanie; Macotela, Yazmn; Moreno-Carranza, Bibiana; Triebel, Jakob; Martnez de la Escalera, Gonzalo

2015-01-01

83

Defect coarsening in blood vessel network formation: self-organization through alignment of elongated cells I  

E-print Network

of elongated cells I Roeland Merks January 16, 2012 Blood vessel growth is key to numerous processes in healthy of cells called endothelial cells, aggregate and self-organize into a primitive blood vessel network of particle Figure 1: Simulated blood vessel network formed out of elongated cells, coarsening over time 1 #12

van Gaans, Onno

84

Defect coarsening in blood vessel network formation: self-organization through alignment of elongated cells  

E-print Network

of elongated cells Roeland Merks January 9, 2014 Blood vessel growth is key to numerous processes in healthy of cells called endothelial cells, aggregate and self-organize into a primitive blood vessel network of particle Figure 1: Simulated blood vessel network formed out of elongated cells, coarsening over time 1 #12

van Gaans, Onno

85

Blood vessels segmentation in retina via wavelet transforms using steerable filters  

Microsoft Academic Search

This paper presents an efficient method for automatic segmentation of blood vessels in retinal images. A set of directional basis filters based on dyadic wavelet transform is designed to enhance blood vessels. It attempts to utilize the linear combination of the wavelet transforms to fix on the blood vessels directional information in retinal images. The directional maps are processed by

Zhu Hongqing; Shu Huazhong; Luo Limin

2004-01-01

86

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

NASA Technical Reports Server (NTRS)

The development of effective vascular therapies requires the understanding of all modes of vessel formation contributing to vasculogenesis, angiogenesis (here termed hemangiogenesis) and lymphangiogenesis. We show that lymphangiogenesis proceeds by blind-ended vessel sprouting via recruitment of isolated endothelial progenitor cells to the tips of growing vessels, whereas hemangiogenesis occurs by non-sprouting vessel expansion from the capillary network, during middevelopment in the quail chorioallantoic membrane (CAM). Blood vessels expanded out of capillaries that displayed transient expression of alpha smooth muscle actin (alphaSMA), accompanied by mural recruitment of migratory progenitor cells expressing SMA. Lymphatics and blood vessels were identified by confocal/fluorescence microscopy of vascular endothelial growth factor (VEGF) receptors VEGFR-1 and VEGFR-2, alphaSMA (expressed on CAM blood vessels but not on lymphatics), homeobox transcription factor Prox-1 (specific to CAM lymphatic endothelium), and the quail hematopoetic/vascular marker, QH-1. Expression of VEGFR-1 was highly restricted to blood vessels (primarily capillaries). VEGFR-2 was expressed intensely in isolated hematopoietic cells, lymphatic vessels and moderately in blood vessels. Prox-1 was absent from endothelial progenitor cells prior to lymphatic recruitment. Although vascular endothelial growth factor-165 (VEGF(sub 165)) is a key regulator of numerous cellular processes in hemangiogenesis and vasculogenesis, the role of VEGF(sub 165) in lymphangiogenesis is less clear. Exogenous VEGF(sub 165) increased blood vessel density without changing endogenous modes of vascular/lymphatic vessel formation or marker expression patterns. However, VEGF(sub 165) did increase the frequency of blood vascular anastomoses and strongly induced the antimaturational dissociation of lymphatics from blood vessels, with frequent formation of homogeneous lymphatic networks.

Parsons-Wingerter, Patricia; McKay, Terri L.; Leontiev, Dmitry; Condrich, Terence K.; DiCorleto, Paul E.

2005-01-01

87

[Stem and progenitor cells in biostructure of blood vessel walls].  

PubMed

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

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

2013-01-01

88

Effect of blood vessel diameter on relative blood flow estimate in Doppler optical coherence tomography algorithms  

NASA Astrophysics Data System (ADS)

In vivo measurement of blood flow in the retina has been made possible with the advent of Fourier domain optical coherence tomography (OCT). Doppler OCT has seen many advances in recent years in algorithms used for quantifying blood flow. We compare the relative retinal blood flow estimates as measured by the standard phase-resolved (PR) algorithm and the more recent moving-scatterer-sensitive (MSS) algorithm as a function of vessel size. We find that the PR-to-MSS flow ratio significantly decreases with decreasing vessel diameter. We also develop a simulation to approximate the scattering from blood cells in tissue and compare the relative blood flow estimates. The flow ratio measured with simulation closely matches that found in vivo. Our simulation predicts that whereas PR underestimates the flow, MSS overestimates it. Our simulation may help to correct for algorithm bias in in vivo retinal flow estimates.

Tokayer, Jason; Huang, David

2011-03-01

89

Blood vessel classification into arteries and veins in retinal images  

NASA Astrophysics Data System (ADS)

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.

Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

2007-03-01

90

Blood vessel repair and regeneration in the ischaemic heart  

PubMed Central

The term therapeutic angiogenesis originated almost two decades ago, following evidence that factors that promote blood vessel formation could be delivered to ischaemic tissues and restore blood flow. Following this proof-of-principle, safety and efficacy of the best-studied angiogenic factors (eg, vascular endothelial growth factor) were demonstrated in early clinical studies. Promising results led to the development of larger controlled trials that, unfortunately, have failed to satisfy the initial expectations of therapeutic angiogenesis for ischaemic heart disease. As the quest to delay the progression to heart failure secondary to ischaemic heart disease continues, alternative therapies have emerged as potential novel treatments to improve myocardial reperfusion and long-term heart function. The disappointing results of the clinical studies using angiogenic factors were followed by mixed results from the cell therapy trials. This review reflects the current angiogenic strategies for the ischaemic heart, their limitations and discusses future perspectives in the light of recent scientific and clinical evidence. It is proposed that combination therapies may be a new direction to advance therapeutic repair and regeneration of blood vessels in the ischaemic heart. PMID:25332783

Zhang, Huajun; van Olden, Casper; Sweeney, Dominic; Martin-Rendon, Enca

2014-01-01

91

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

NASA Astrophysics Data System (ADS)

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.

Bose, Sayan; Banerjee, Moloy

2015-01-01

92

Plasma membrane electron transport in frog blood vessels.  

PubMed

In an attempt to see if frog blood vessels possess a plasma membrane electron transport system, the postcaval vein and aorta isolated from Rana tigrina were tested for their ability to reduce ferricyanide, methylene blue, and 2,6-dichloroindophenol. While the dyes remained unchanged, ferricyanide was reduced to ferrocyanide. This reduction was resistant to inhibition by cyanide and azide. Heptane extraction or formalin fixation of the tissues markedly reduced the capability to reduce ferricyanide. Denuded aortas retained only 30% of the activity of intact tissue. Our results indicate that the amphibian postcaval vein and aorta exhibit plasma membrane electron transport. PMID:20093738

Rao, Rashmi P; Nalini, K; Rao, J Prakasa

2009-12-01

93

Retinal blood vessel segmentation using gabor filter and top-hat transform  

Microsoft Academic Search

Retinal blood vessel segmentation is a widely used process in diagnosis of various diseases such as diabetic retinopathy, glaucoma and arteriosclerosis. Therefore, an automated tool developed for vessel segmentation could be employed in diagnosis of those illnesses to help ophthalmologists. In this paper, we suggest a method to segment retinal blood vessels automatically. In the method, we apply top-hat transform

Zafer Yavuz; Cemal Kose

2011-01-01

94

Polar Run-Length Features in Segmentation of Retinal Blood Vessels  

Microsoft Academic Search

Manual segmentation of retinal blood vessels in optic fundus images is a tiresome task. Several methods have previously been proposed for the automatic segmentation of retinal blood vessels. In this paper we propose a classifier-based method. First the images are preprocessed so that the within class variability of the vessel and background classes are minimized. Next, the image is scanned

S. H. Rezatofighi; A. Roodaki; A. Pourmorteza; H. Soltanian-Zadeh

2009-01-01

95

Retinal Blood Vessels Segmentation Using the Radial Projection and Supervised Classification  

Microsoft Academic Search

The low-contrast and narrow blood vessels in retinal images are difficult to be extracted but useful in reveal- ing certain systemic disease. Motivated by the goals of improving detection of such vessels, we propose the ra- dial projection method to locate the vessel centerlines. Then the supervised classification is used for extract- ing the major structures of vessels. The final

Qinmu Peng; Xinge You; Long Zhou; Yiu-ming Cheung

2010-01-01

96

Blood Vessel Segmentation from Color Retinal Images using Unsupervised Texture Classification  

Microsoft Academic Search

Automated blood vessel segmentation is an important issue for assessing retinal abnormalities and diagnoses of many dis- eases. The segmentation of vessels is complicated by huge variations in local contrast, particularly in case of the minor vessels. In this paper, we propose a new method of texture based vessel segmentation to overcome this problem. We use Gaussian and L?a?b? perceptually

Alauddin Bhuiyan; Baikunth Nath; Joselto J. Chua; Kotagiri Ramamohanarao

2007-01-01

97

Triamcinolone Acetonide Selectively Inhibits Angiogenesis in Small Blood Vessels and Decreases Vessel Diameter within the Vascular Tree  

NASA Technical Reports Server (NTRS)

The steroid triamcinolone acetonide (TA) is a potent anti-angiogenesis drug used to treat retinal vascular diseases that include diabetic retinopathy, vascular occlusions and choroidal neovascularization. To quantify the effects of TA on branching morphology within the angiogenic microvascular tree of the chorioallantoic membrane (CAM) of quail embryos. Increasing concentrations of TA (0-16 ng/ml) were applied topically on embryonic day 7 (E7) to the chorioallantoic membrane (CAM) of quail embryos cultured in Petri dishes, and incubated for an additional 24 or 48 hours until fixation. Binary (black/white) microscopic images of arterial end points were quantified by VESGEN software (for Generational Analysis of Vessel Branching) to obtain major vascular parameters that include vessel diameter (Dv), fractal dimension (Df), tortuosity (Tv) and densities of vessel area, length, number and branch point (Av, Lv, Nv and Brv). For assessment of specific changes in vascular morphology induced by TA, the VESGEN software automatically segmented the vascular tree into branching generations (G1...G10) according to changes in vessel diameter and branching. Vessel density decreased significantly up to 34% as the function of increasing concentration of TA according to Av, Lv, Brv, Nv and Df. TA selectively inhibited the growth of new, small vessels, because Lv decreased from 13.14plus or minus 0.61 cm/cm2 for controls to 8.012 plus or minus 0.82 cm/cm2 at 16 ng TA/ml in smaller branching generations (G7-G10), and for Nv from 473.83 plus or minus 29.85 cm(-)2 to 302.32 plus or minus 33.09 cm-()2. In contrast, vessel diameter (Dv) decreased throughout the vascular tree (G1-G10).

McKay, Terri L.; Gredeon, Dan J.; Vickerman, Mary B.; Hylton, alan G.; Ribita, Daniela; Olar, Harry H.; Kaiser, Peter K.; Parsons-Wingerter, Patricia

2007-01-01

98

Mouse Studies Show Gene Therapy Method Holds Promise in Targeting Tumor Blood Vessels for Destruction  

Cancer.gov

Cancer researchers have reported the development of a novel method for delivering a therapeutic gene specifically to the blood vessels of tumors in mice. Once delivered, the gene produces a protein that damages the blood vessels and disrupts the blood flow to tumors, but not to the surrounding tissue.

99

Author's personal copy The behaviors of ferromagnetic nano-particles in and around blood vessels  

E-print Network

Author's personal copy The behaviors of ferromagnetic nano-particles in and around blood vessels Blood vessels Treatment depth Non-dimensional parameters In-vivo experiments a b s t r a c t In magnetic drug delivery, therapeutic magnetizable particles are typically injected into the blood stream

Shapiro, Benjamin

100

Effect of soluble epoxide hydrolase inhibition on epoxyeicosatrienoic acid metabolism in human blood vessels  

E-print Network

blood vessels Xiang Fang,1 Neal L. Weintraub,2,3,4 Ryan B. McCaw,1 Shanming Hu,1 Shawn D. Harmon,1 James on epoxyeicosatrienoic acid metabolism in human blood vessels. Am J Physiol Heart Circ Physiol 287: H2412­H2420, 2004 epoxide hydrolase (sEH) inhibition on epoxyei- cosatrienoic acid (EET) metabolism in intact human blood

Hammock, Bruce D.

101

Medical Tests and Procedures for Finding and Treating Heart and Blood Vessel Disease  

MedlinePLUS

... left in place to keep the blood vessel open, helping blood to flow freely. A drug-eluting stent, also called a drug-coated stent, is covered with medicine that helps keep the blood vessel open. Stress test See exercise stress test.

102

A histochemical study on the innervation of cerebral blood vessels in the bullfrog.  

PubMed

Specific histochemical techniques for the demonstration of catecholamine and acetylcholinesterase have been used to study the distribution of adrenergic and cholinergic nerves on the cerebral blood vessels of bullfrog, Rana catesbeiana. The adrenergic nerve meshworks on the cerebral arteries of bullfrog were less dense, had a more elongate appearance along the arterial axis as compared with those of mammals and were rather similar to those of snakes. The nerve plexuses on the cerebral carotid artery and its main branches were somewhat denser than those on the basilar artery. The most characteristic feature of innervation in the bullfrog cerebral vessels was that no acetylcholinesterase-positive fibres were observed on the extraparenchymal arteries, whereas, in all higher vertebrates investigated so far, the cerebral arteries have been found to be dually innervated although differences in the density of innervation of the two nerves may exist. This suggests that the peripheral adrenergic innervation on the cerebral blood vessels appeared earlier than the cholinergic one in the evolution of vertebrates. On the other hand, both adrenergic and acetylcholinesterase-positive fibres were observed in close contact with parenchymal arterioles and capillaries suggesting the possible existence of a dual central innervation. This feature, however, was by no means common. Thus, the central neurons have a significant influence on the cerebral circulation in the bullfrog is somewhat equivocal. Most of the pial and the parenchymal small vessels and the parenchymal capillaries exhibited a heavy acetylcholinesterase activity on the vascular walls. Although the significance of the enzyme is obscure as yet, this has to be considered in relation to the regulatory mechanism of the cerebral circulation. PMID:309891

Tagawa, T; And, K; Wasano, T; Iijima, T

1979-01-01

103

Automatic Segmentation of Blood Vessels in Colour Retinal Images using Spatial Gabor Filter and Multiscale Analysis  

Microsoft Academic Search

Retinal blood vessels are significant anatomical structures in ophthalmic images. Automatic segmentation of blood vessels\\u000a is one of the important steps in computer aided diagnosis system for the detection of diseases such as Diabetic Retinopathy\\u000a that affect human retina. We propose a method for the segmentation of retinal blood vessels using Spatial Gabor filters as\\u000a they can be tuned to

P. C. Siddalingaswamy; K. Gopalakrishna Prabhu

104

Elementary mechanics of the endothelium of blood vessels.  

PubMed

The endothelium lining human arteries is a continuum of endothelial cells. The flowing blood imposes a shear stress on the endothelium. To compute the internal stress in the endothelium, we use two alternative hypotheses: 1) The cell content is fluid-like so that at steady-state it has no shear stress. 2) The cell content is solid-like. Under hypothesis No. 1, the membrane tension in the upper cell membrane grows in the direction opposite to the blood flow at a rate equal to the blood shear stress. At the junction of two neighboring cells the membrane tension in the downstream cell is transmitted partly to the basal lamina, and partly to the upstream cell. The transmission depends on the osmotic or static pressure difference between the cell and blood. If the static pressure difference is zero, the tension in the upper cell membrane will accumulate upstream. At other values of static pressure, the cell membrane tension may increase, decrease, or fluctuate along the vessel depending on the inclination of the side walls of the cells at the junctions. To determine the sidewall inclinations, we propose to use the complementary energy theorem. Under hypothesis No. 2, the cell content can bear shear, which tends to reduce the cell membrane tension; but the cell membrane tension accumulation phenomenon discussed above remains valid. These results are used to analyze the interaction of the cell membrane and cell nucleus; and the effect of turbulences in the flow on causing large fluctuations in cell membrane tension and vertical oscillations of the nuclei. The implication of tensile stress on the permeability of the cell membrane is discussed. We conclude that for the study of mass transport and stress fibers in the endothelial cells, one should consider the interaction of neighboring endothelial cells as a continuum, and shift attention from the shear stress in the blood to the principal stresses in the cells. PMID:8445886

Fung, Y C; Liu, S Q

1993-02-01

105

Blood vessel segmentation using line-direction vector based on Hessian analysis  

NASA Astrophysics Data System (ADS)

For decision of the treatment strategy, grading of stenoses is important in diagnosis of vascular disease such as arterial occlusive disease or thromboembolism. It is also important to understand the vasculature in minimally invasive surgery such as laparoscopic surgery or natural orifice translumenal endoscopic surgery. Precise segmentation and recognition of blood vessel regions are indispensable tasks in medical image processing systems. Previous methods utilize only ``lineness'' measure, which is computed by Hessian analysis. However, difference of the intensity values between a voxel of thin blood vessel and a voxel of surrounding tissue is generally decreased by the partial volume effect. Therefore, previous methods cannot extract thin blood vessel regions precisely. This paper describes a novel blood vessel segmentation method that can extract thin blood vessels with suppressing false positives. The proposed method utilizes not only lineness measure but also line-direction vector corresponding to the largest eigenvalue in Hessian analysis. By introducing line-direction information, it is possible to distinguish between a blood vessel voxel and a voxel having a low lineness measure caused by noise. In addition, we consider the scale of blood vessel. The proposed method can reduce false positives in some line-like tissues close to blood vessel regions by utilization of iterative region growing with scale information. The experimental result shows thin blood vessel (0.5 mm in diameter, almost same as voxel spacing) can be extracted finely by the proposed method.

Nimura, Yukitaka; Kitasaka, Takayuki; Mori, Kensaku

2010-03-01

106

Translating the Conversation Between the Brain and Blood Vessels  

NSDL National Science Digital Library

?We?re studying why people who are obese become hypertensive,? Dr. Schreihofer said of one aspect of her work. ?We believe this is due to something about the obese state: We don?t know what that is, but we?re starting to rule things out.? 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 rats? brains could sense the stretch but still became hypertensive, eliminating that mechanism as a possibility.

APS Communications Office (American Physiological Society Communications Office)

2006-04-21

107

Blood Vessel Normalization in the Hamster Oral Cancer Model for Experimental Cancer Therapy Studies  

SciTech Connect

Normalization of tumor blood vessels improves drug and oxygen delivery to cancer cells. The aim of this study was to develop a technique to normalize blood vessels in the hamster cheek pouch model of oral cancer. Materials and Methods: Tumor-bearing hamsters were treated with thalidomide and were compared with controls. Results: Twenty eight hours after treatment with thalidomide, the blood vessels of premalignant tissue observable in vivo became narrower and less tortuous than those of controls; Evans Blue Dye extravasation in tumor was significantly reduced (indicating a reduction in aberrant tumor vascular hyperpermeability that compromises blood flow), and tumor blood vessel morphology in histological sections, labeled for Factor VIII, revealed a significant reduction in compressive forces. These findings indicated blood vessel normalization with a window of 48 h. Conclusion: The technique developed herein has rendered the hamster oral cancer model amenable to research, with the potential benefit of vascular normalization in head and neck cancer therapy.

Ana J. Molinari; Romina F. Aromando; Maria E. Itoiz; Marcela A. Garabalino; Andrea Monti Hughes; Elisa M. Heber; Emiliano C. C. Pozzi; David W. Nigg; Veronica A. Trivillin; Amanda E. Schwint

2012-07-01

108

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

PubMed Central

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, bifurcations 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.

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

2014-01-01

109

Aquaporin-1 in blood vessels of rat circumventricular organs.  

PubMed

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

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

2010-04-01

110

Statistical pattern analysis of blood vessel features on retina images and its application to blood vessel mapping algorithms.  

PubMed

Computer based modeling and analysis of blood vessel (BV) networks is essential for automated detection and tracking of anomalies and structural changes in retina images. Among many published techniques for automated BV mapping, optimal selection of thresholds to delineate BV pixels from their background pixels remains an open problem. In this paper we propose a novel representation of a BV pixel feature, daisy graph, using rotational contrast transform (RCT), and two feature descriptors energy Ep and symmetry difference Sp of the daisy graph. Non-BV pixels are separated from BV and boundary pixels based on Ep. Fitness of the lognormal distribution to Sp of BV pixels with negative Ep has been tested extensively for images in the STARE and DRIVE databases. Based on statistical pattern analysis in the feature space, we propose a fast self-calibrated BV mapping algorithm which achieve comparable and statistically sound performance as contemporary solutions. PMID:25571441

Huajun Ying; Xing Wang; Jyh-Charn Liu

2014-08-01

111

Bone marrow blood vessel ossification and "microvascular dead space" in rat and human long bone.  

PubMed

Severe calcification of the bone microvascular network was observed in rats, whereby the bone marrow blood vessels appeared ossified. This study sought to characterize the magnitude of ossification in relation to patent blood vessels and adipocyte content in femoral diaphyses. Additionally, this study confirmed the presence of ossified vessels in patients with arteriosclerotic vascular disease and peripheral vascular disease and cellulitis. Young (4-6 month; n=8) and old (22-24 month; n=8) male Fischer-344 rats were perfused with barium sulfate to visualize patent bone marrow blood vessels. Femoral shafts were processed for bone histomorphometry to quantify ossified (Goldner's Trichrome) and calcified (Alizarin Red) vessels. Adipocyte content was also determined. Additional femora (n=5/age group) were scanned via ?CT to quantify microvascular ossification. Bone marrow blood vessels from the rats and the human patients were also isolated and examined via microscopy. Ossified vessels (rats and humans) had osteocyte lacunae on the vessel surfaces and "normal" vessels were transitioning into bone. The volume of ossified vessels was 4800% higher (p<0.05) in the old vs. young rats. Calcified and ossified vessel volumes per tissue volume and calcified vessel volume per patent vessel volume were augmented (p<0.05) 262%, 375% and 263%, respectively, in the old vs. young rats. Ossified and patent vessel number was higher (171%) and lower (40%), respectively, in the old vs. young rats. Finally, adipocyte volume per patent vessel volume was higher (86%) with age. This study is the first to report ossification of bone marrow blood vessels in rats and humans. Ossification presumably results in "microvascular dead space" in regard to loss of patency and vasomotor function as opposed to necrosis. Progression of bone microvascular ossification may provide the common link associated with age-related changes in bone and bone marrow. The clinical implications may be evident in the difficulties treating bone disease in the elderly. PMID:24680721

Prisby, Rhonda D

2014-07-01

112

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

Microsoft Academic Search

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

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

1989-01-01

113

Blood Vessel Fibronectin Increases in Conjunction with Endothelial Cell Proliferation and Capillary Ingrowth During Wound Healing  

Microsoft Academic Search

The regulation of angiogenesis and alterations in the structure of blood vessels taking part in wound healing are poorly understood. In studies of guinea pig 4-mm skin wounds, left uncovered for 128 days, biopsied and processed for 1-?m section and immunofluorescence, we found that fibronectin in blood vessel walls markedly increased in conjunction with endothelial cell proliferation and capillary ingrowth.

Richard A. F. Clark; Patricia DellaPelle; Eleanor Manseau; Joan M. Lanigan; Harold F. Dvorak; Robert B. Colvin

1982-01-01

114

A Novel Approach for Blood Vessel Edge Detection in Retinal Images  

Microsoft Academic Search

Blood vessel appearance is an important indicator for many diagnoses, including diabetes, hypertension, and arteriosclerosis. Blood Vessel edge detection in retinal images is very important in medical image processing. A lot of algorithms have been suggested for extracting medical image edges, and however, obtaining continuous edges with less over-detection points is difficult for edge extraction. In this paper, we propose

Yu Guang Zhang; Xin Yong Guo; Lei Hu; Qin He Dang; Di Chen; Dong Cui; Qing Jiao

2009-01-01

115

Development of retinal blood vessel segmentation methodology using wavelet transforms for assessment of diabetic retinopathy  

Microsoft Academic Search

Automated image processing has the potential to assist in the early detection of diabetes, by detecting changes in blood vessel diameter and patterns in the retina. This paper describes the development of segmentation methodology in the processing of retinal blood vessel images obtained using non-mydriatic colour photography. The methods used include wavelet analysis, supervised classifier probabilities and adaptive threshold procedures,

D. J. Cornforth; H. J. Jelinek; J. J. G. Leandro; J. V. B. Soares; R. M. Cesar; M. J. Cree; P. Mitchell; T. Bossomaier

2005-01-01

116

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

E-print Network

Simulations of Blood Flow in Plain Cylindrical and Constricted Vessels with Single Cell Resolution blood cells (RBCs, also called erythro- cytes) in a Newtonian liquid, the blood plasma. The other:[6] within this approach we aim at a minimal resolution of red blood cells which allows for a simple

Harting, Jens

117

High speed detection of retinal blood vessels in fundus image using phase congruency  

Microsoft Academic Search

Detection of blood vessels in retinal fundus image is the preliminary step to diagnose several retinal diseases. There exist\\u000a several methods to automatically detect blood vessels from retinal image with the aid of different computational methods.\\u000a However, all these methods require lengthy processing time. The method proposed here acquires binary vessels from a RGB retinal\\u000a fundus image in almost real

M. Ashraful Amin; Hong Yan

2011-01-01

118

Tenascin-C in development and disease of blood vessels.  

PubMed

Tenascin-C (TNC) is an extracellular glycoprotein categorized as a matricellular protein. It is highly expressed during embryonic development, wound healing, inflammation, and cancer invasion, and has a wide range of effects on cell response in tissue morphogenesis and remodeling including the cardiovascular system. In the heart, TNC is sparsely detected in normal adults but transiently expressed at restricted sites during embryonic development and in response to injury, playing an important role in myocardial remodeling. Although TNC in the vascular system appears more complex than in the heart, the expression of TNC in normal adult blood vessels is generally low. During embryonic development, vascular smooth muscle cells highly express TNC on maturation of the vascular wall, which is controlled in a way that depends on the embryonic site of cell origin. Strong expression of TNC is also linked with several pathological conditions such as cerebral vasospasm, intimal hyperplasia, pulmonary artery hypertension, and aortic aneurysm/ dissection. TNC synthesized by smooth muscle cells in response to developmental and environmental cues regulates cell responses such as proliferation, migration, differentiation, and survival in an autocrine/paracrine fashion and in a context-dependent manner. Thus, TNC can be a key molecule in controlling cellular activity in adaptation during normal vascular development as well as tissue remodeling in pathological conditions. PMID:25125186

Imanaka-Yoshida, Kyoko; Yoshida, Toshimichi; Miyagawa-Tomita, Sachiko

2014-09-01

119

The evolution of nitric oxide signalling in vertebrate blood vessels.  

PubMed

Nitric oxide is one of the most important signalling molecules involved in the regulation of physiological function. It first came to prominence when it was discovered that the vascular endothelium of mammals synthesises and releases nitric oxide (NO) to mediate a potent vasodilation. Subsequently, it was shown that NO is synthesised in the endothelium by a specific isoform of nitric oxide synthase (NOS) called NOS3. Following this discovery, it was assumed that an endothelial NO/NOS3 system would be present in all vertebrate blood vessels. This review will discuss the latest genomic, anatomical and physiological evidence which demonstrates that an endothelial NO/NOS3 signalling is not ubiquitous in non-mammalian vertebrates, and that there have been key evolutionary steps that have led to the endothelial NO signalling system being a regulatory system found only in reptiles, birds and mammals. Furthermore, the emerging role of nitrite as an endocrine source of NO for vascular regulation is discussed. PMID:25502832

Donald, John A; Forgan, Leonard G; Cameron, Melissa S

2015-02-01

120

Fabrication of cell microintegrated blood vessel constructs through electrohydrodynamic atomization  

PubMed Central

Biodegradable synthetic matrices that resemble the size scale, architecture and mechanical properties of the native extracellular matrix can be fabricated through electrospinning. Tubular conduits may also be fabricated with properties appropriate for vascular tissue engineering. Achieving large cell infiltrate within the electrospun matrix in vitro remains time consuming and challenging. This difficulty was overcome by electrospraying smooth muscle cells concurrently with electrospinning of a biodegradable, elastomeric poly(ester urethane)urea (PEUU) small diameter conduit. Constructs were cultured statically or in spinner flasks. Hematoxylin and eosin (H&E) staining demonstrated qualitatively uniform SMC integration radially and circumferentially within the conduit after initial static culture. In comparison with static culture, samples cultured in spinner flasks indicated 2.4 times more viable cells present from MTT and significantly larger numbers of SMCs spread within the electrospun fiber networks by H&E image analysis. Conduits were strong and flexible with mechanical behaviors that mimicked those of native arteries, including static compliance of 1.6 0.5 10?3 mmHg?1, dynamic compliance of 8.7 1.8 10?4 mmHg?1, burst strengths of 1750 220 mmHg, and suture retention. This method to rapidly and efficiently integrate cells into a strong, compliant biodegradable tubular matrix represents a significant achievement as a tissue engineering approach for blood vessel replacement. PMID:17337048

Stankus, John J.; Soletti, Lorenzo; Fujimoto, Kazuro; Hong, Yi; Vorp, David A.; Wagner, William R.

2007-01-01

121

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.

122

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

PubMed

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

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

2014-01-01

123

Sanford-Burnham study finds helping tumor blood vessels mature could make cancer drugs more effective  

Cancer.gov

To survive, tumors need blood supply to provide them with nutrients and oxygen. To get that supply, cancer cells stimulate new blood vessel growtha process called tumor angiogenesis. What if, rather than putting a stop to angiogenesis, we could help tumor blood vessels mature more completely, so tumor-killing therapies could more effectively reach their targets? In a paper published August 14 in the journal Cancer Cell, Sanford-Burnham researchers found a molecule that promotes the tumor vessel maturation processa discovery that might provide a method for improving cancer drug delivery.

124

A Computational Model Predicting Disruption of Blood Vessel Development  

PubMed Central

Vascular development is a complex process regulated by dynamic biological networks that vary in topology and state across different tissues and developmental stages. Signals regulating de novo blood vessel formation (vasculogenesis) and remodeling (angiogenesis) come from a variety of biological pathways linked to endothelial cell (EC) behavior, extracellular matrix (ECM) remodeling and the local generation of chemokines and growth factors. Simulating these interactions at a systems level requires sufficient biological detail about the relevant molecular pathways and associated cellular behaviors, and tractable computational models that offset mathematical and biological complexity. Here, we describe a novel multicellular agent-based model of vasculogenesis using the CompuCell3D (http://www.compucell3d.org/) modeling environment supplemented with semi-automatic knowledgebase creation. The model incorporates vascular endothelial growth factor signals, pro- and anti-angiogenic inflammatory chemokine signals, and the plasminogen activating system of enzymes and proteases linked to ECM interactions, to simulate nascent EC organization, growth and remodeling. The model was shown to recapitulate stereotypical capillary plexus formation and structural emergence of non-coded cellular behaviors, such as a heterologous bridging phenomenon linking endothelial tip cells together during formation of polygonal endothelial cords. Molecular targets in the computational model were mapped to signatures of vascular disruption derived from in vitro chemical profiling using the EPA's ToxCast high-throughput screening (HTS) dataset. Simulating the HTS data with the cell-agent based model of vascular development predicted adverse effects of a reference anti-angiogenic thalidomide analog, 5HPP-33, on in vitro angiogenesis with respect to both concentration-response and morphological consequences. These findings support the utility of cell agent-based models for simulating a morphogenetic series of events and for the first time demonstrate the applicability of these models for predictive toxicology. PMID:23592958

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

2013-01-01

125

TOPAZ: a computer code for modeling heat transfer and fluid flow in arbitrary networks of pipes, flow branches, and vessels  

Microsoft Academic Search

An overview of the computer code TOPAZ (Transient-One-Dimensional Pipe Flow Analyzer) is presented. TOPAZ models the flow of compressible and incompressible fluids through complex and arbitrary arrangements of pipes, valves, flow branches and vessels. Heat transfer to and from the fluid containment structures (i.e. vessel and pipe walls) can also be modeled. This document includes discussions of the fluid flow

Winters

1984-01-01

126

Dimensional analysis of blood vessels in the pressure myograph  

NASA Astrophysics Data System (ADS)

The accuracy of conventional and emerging methods for the dimensional analysis of optically imaged arterial vessels, isolated in a pressure myograph, is investigated. The pressure myograph is a device used to study the structure and function of isolated sections of small resistance arteries, as a function of chemical, mechanical and electrical stimuli. The arterial wall and lumen dimensions are particularly important indicators of anatomy and pathology. The conventional method of dimensional analysis uses edge detection, however the accuracy of this approach is questionable when the vessel is in a contracted state since contrast deteriorates or is lost between lumen and vessel wall. The conventional and emerging methods are examined experimentally with vessel phantoms, to provide known characteristics. A novel algorithm, based on a measurement of the vessel extinction coefficient, is also examined theoretically and experimentally. A discussion centers on the possibility for realistic lumen size measurement when edge detection can not be applied and when the accuracy of edge detection is questionable.

Crabtree, Vincent P.; Smith, Peter R.

1999-01-01

127

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

PubMed

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

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

2013-01-01

128

TNF-alpha drives remodeling of blood vessels and lymphatics in sustained airway inflammation in mice.  

PubMed

Inflammation is associated with blood vessel and lymphatic vessel proliferation and remodeling. The microvasculature of the mouse trachea provides an ideal opportunity to study this process, as Mycoplasma pulmonis infection of mouse airways induces widespread and sustained vessel remodeling, including enlargement of capillaries into venules and lymphangiogenesis. Although the mediators responsible for these vascular changes in mice have not been identified, VEGF-A is known not to be involved. Here, we sought to determine whether TNF-alpha drives the changes in blood vessels and lymphatics in M. pulmonis-infected mice. The endothelial cells, but not pericytes, of blood vessels, but not lymphatics, were immunoreactive for TNF receptor 1 (TNF-R1) and lymphotoxin B receptors. Most TNF-R2 immunoreactivity was on leukocytes. Infection resulted in a large and sustained increase in TNF-alpha expression, as measured by real-time quantitative RT-PCR, and smaller increases in lymphotoxins and TNF receptors that preceded vessel remodeling. Substantially less vessel remodeling and lymphangiogenesis occurred when TNF-alpha signaling was inhibited by a blocking antibody or was silenced in Tnfr1-/- mice. When administered after infection was established, the TNF-alpha-specific antibody slowed but did not reverse blood vessel remodeling and lymphangiogenesis. The action of TNF-alpha on blood vessels is probably mediated through direct effects on endothelial cells, but its effects on lymphangiogenesis may require inflammatory mediators from recruited leukocytes. We conclude that TNF-alpha is a strong candidate for a mediator that drives blood vessel remodeling and lymphangiogenesis in inflammation. PMID:19759514

Baluk, Peter; Yao, Li-Chin; Feng, Jennifer; Romano, Talia; Jung, Sonia S; Schreiter, Jessica L; Yan, Li; Shealy, David J; McDonald, Donald M

2009-10-01

129

A simplified model for red cell dynamics in small blood vessels  

E-print Network

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.

Piero Olla

1998-05-07

130

Temperature evolution in tissues embedded with large blood vessels during photo-thermal heating.  

PubMed

During laser-assisted photo-thermal therapy, the temperature of the heated tissue region must rise to the therapeutic value (e.g., 43C) for complete ablation of the target cells. Large blood vessels (larger than 500 micron in diameter) at or near the irradiated tissues have a considerable impact on the transient temperature distribution in the tissue. In this study, the cooling effects of large blood vessels on temperature distribution in tissues during laser irradiation are predicted using finite element based simulation. A uniform flow is assumed at the entrance and three-dimensional conjugate heat transfer equations in the tissue region and the blood region are simultaneously solved for different vascular models. A volumetric heat source term based on Beer-Lambert law is introduced into the energy equation to account for laser heating. The heating pattern is taken to depend on the absorption and scattering coefficients of the tissue medium. Experiments are also conducted on tissue mimics in the presence and absence of simulated blood vessels to validate the numerical model. The coupled heat transfer between thermally significant blood vessels and their surrounding tissue for three different tissue-vascular networks are analyzed keeping the laser irradiation constant. A surface temperature map is obtained for different vascular models and for the bare tissue (without blood vessels). The transient temperature distribution is seen to differ according to the nature of the vascular network, blood vessel size, flow rate, laser spot size, laser power and tissue blood perfusion rate. The simulations suggest that the blood flow through large blood vessels in the vicinity of the photothermally heated tissue can lead to inefficient heating of the target. PMID:24679976

Paul, Anup; Narasimhan, Arunn; Kahlen, Franz J; Das, Sarit K

2014-04-01

131

The astrocyte-expressed integrin ?v?8 governs blood vessel sprouting in the developing retina  

PubMed Central

The mouse retina is vascularized after birth when angiogenic blood vessels grow and sprout along a pre-formed latticework of astrocytes. How astrocyte-derived cues control patterns of blood vessel growth and sprouting, however, remains enigmatic. Here, we have used molecular genetic strategies in mice to demonstrate that ?v?8 integrin expressed in astrocytes is essential for neovascularization of the developing retina. Selective ablation of ?v or ?8 integrin gene expression in astrocytes leads to impaired blood vessel sprouting and intraretinal hemorrhage, particularly during formation of the secondary vascular plexus. These pathologies correlate, in part, with diminished ?v?8 integrin-mediated activation of extracellular matrix-bound latent transforming growth factor ?s (TGF?s) and defective TGF? signaling in vascular endothelial cells, but not astrocytes. Collectively, our data demonstrate that ?v?8 integrin is a component of a paracrine signaling axis that links astrocytes to blood vessels and is essential for proper regulation of retinal angiogenesis. PMID:22069187

Hirota, Shinya; Liu, Qian; Lee, Hye Shin; Hossain, Mohammad G.; Lacy-Hulbert, Adam; McCarty, Joseph H.

2011-01-01

132

Resistance of noradrenaline in blood vessels to depletion by 6-hydroxydopamine or immunosympathectomy  

PubMed Central

1. The degree of the decrease in the noradrenaline concentrations caused by 6-hydroxydopamine or immunosympathectomy was different in different areas of the cardiovascular system. 2. In rats or guinea-pigs 6-hydroxydopamine depleted the noradrenaline content of the heart by 90%, of the mesenteric vein by 80% and of the mesenteric artery and aorta by 30-60%. Immunosympathectomy elicited a 70% reduction in the cardiac noradrenaline but only a 50% reduction in the noradrenaline of the blood vessels of the rat. 3. The tyrosine hydroxylase activity of the heart, blood vessels, or adrenal glands was not significantly altered 2 weeks after 6-hydroxydopamine. Nor was the monoamine oxidase activity in heart or blood vessels changed. 4. The inconsistent ability of both 6-hydroxydopamine and immunosympathectomy to abolish experimental hypertension may be due to the partial persistence of noradrenaline and functional sympathetic nervous system activity in the blood vessels. PMID:4401306

Berkowitz, B. A.; Spector, S.; Tarver, J. H.

1972-01-01

133

Some with Kidney Stones Might Have Calcium Buildup in Blood Vessels  

MedlinePLUS

... enable JavaScript. Some With Kidney Stones Might Have Calcium Buildup in Blood Vessels: Study These patients might ... 2015) Friday, January 30, 2015 Related MedlinePlus Pages Calcium Heart Diseases--Prevention Kidney Stones FRIDAY, Jan. 30, ...

134

Factory neovessels: engineered human blood vessels secreting therapeutic proteins as a new drug delivery system  

Microsoft Academic Search

Several works have shown the feasibility of engineering functional blood vessels in vivo using human endothelial cells (ECs). Going further, we explored the therapeutic potential of neovessels after gene-modifying the ECs for the secretion of a therapeutic protein. Given that these vessels are connected with the host vascular bed, we hypothesized that systemic release of the expressed protein is immediate.

M Compte; V Alonso-Camino; P Santos-Valle; M Cuesta; D Snchez-Martn; M R Lpez; J L Vicario; C Salas; L Sanz; L lvarez-Vallina

2010-01-01

135

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

E-print Network

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

Laidlaw, David

136

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

137

Development of blood vessel search system using near-infrared light for laparoscopic surgery  

NASA Astrophysics Data System (ADS)

Our objective of this study is to develop a miniature and high accuracy automatic 3D blood vessel searching system, which will be introduced in the laparoscopic operation with the minimally invasive surgery. Now, the conventional optical system used in the laparoscopic surgery has many difficulties of blood vessel imaging and detection, because the peripheral bio-tissue located around the blood vessel disturbs the light wave propagation, disperses and refracts. Consequently, only unclear image is obtained. We develop a new blood vessel detecting system by using Near-Infrared (NIR) light, two CMOS camera modules and a comprehensive image processing technique, which is implemented in the laparoscope pipe with 25mm in diameter. We adopt the stereo method for the searching system to determine 3D blood vessel location. The blood vessel visualization system adopts hemoglobin's absorption characteristics of the NIR light, which has high permeability for the bio-tissue and absorbency for the hemoglobin. A sharpening process is employed to improve the image quality of original ones, through the LoG filter and the un-sharp-mask processing. 2D location of the blood vessel is calculated from luminance distribution of the image and its depth is calculated by the stereo method. A validity of our blood vessel visualization and 3D detecting system was examined through the comparison with the imaging and detecting the results of organization phantoms, which embedded at known depths under the surface. Experimental results of depth obtained by our detecting system showed good agreements with the given depths, and the availability of this system is confirmed.

Narita, K.; Nakamachi, E.; Morita, Y.; Hagiwara, A.

2013-09-01

138

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

E-print Network

Forces on a Wall-Bound Leukocyte in a Small Vessel Due to Red Cells in the Blood Stream Amir H. G at Urbana-Champaign, Urbana, Illinois ABSTRACT As part of the inflammation response, white blood cells character of blood, especially in small vessels where the red blood cells must substantially deform to pass

Freund, Jonathan B.

139

Impact of Cold Ischemia on Mitochondrial Function in Porcine Hearts and Blood Vessels  

PubMed Central

The effects of cold storage using Custodiol (Histidine-Tryptophan-Ketoglutarate, HTK) or isotonic saline solution on mitochondrial function in hearts (left and rights ventricles) and various blood vessels of pigs were investigated. Hearts, saphenous veins, internal-mammary-arteries and aortas of male landrace pigs were harvested and exposed to cold ischemia in either saline or Custodiol-HTK solution. Mitochondrial function was measured in situ in permeabilized fibers by high-resolution respirometry. Mitochondrial respiratory capacities (maximal respiration rates) were similar in the right and left ventricle in controls and after 14 h of cold storage were significantly better preserved in Custodiol-HTK than in saline solution. Mitochondrial respiration rates in various blood vessels including aorta, arteries and veins were less than 5% of myocardium rates. In contrast to the pig heart, in some blood vessels, like veins, mitochondrial function remained stable even after 24 h of cold ischemia. HTK-Custodiol protection of mitochondrial function after prolonged cold ischemia was observed in the myocardium but not in blood vessels. HTK-Custodiol solution thus offers significant protection of myocardial mitochondria against cold ischemic injury and can be used as efficient preservation solution in organ transplantation but probably has no benefit for blood vessels preservation. Analysis of mitochondrial function can be used as a valuable approach for the assessment of cold ischemic injury in various tissues including pig heart and various blood vessels. PMID:24213604

Wiedemann, Dominik; Schachner, Thomas; Bonaros, Nikolaos; Dorn, Melissa; Andreas, Martin; Kocher, Alfred; Kuznetsov, Andrey V.

2013-01-01

140

Prevent Diabetes Problems: Keep Your Heart and Blood Vessels Healthy  

MedlinePLUS

... vessel problems. [ Top ] What should I do each day to stay healthy with diabetes? Follow the healthy ... Be active a total of 30 minutes most days. Ask your doctor what activities are best for ...

141

Automated segmentation of retinal blood vessels in spectral domain optical coherence tomography scans  

PubMed Central

The correct segmentation of blood vessels in optical coherence tomography (OCT) images may be an important requirement for the analysis of intra-retinal layer thickness in human retinal diseases. We developed a shape model based procedure for the automatic segmentation of retinal blood vessels in spectral domain (SD)-OCT scans acquired with the Spectralis OCT system. The segmentation procedure is based on a statistical shape model that has been created through manual segmentation of vessels in a training phase. The actual segmentation procedure is performed after the approximate vessel position has been defined by a shadowgraph that assigns the lateral vessel positions. The active shape model method is subsequently used to segment blood vessel contours in axial direction. The automated segmentation results were validated against the manual segmentation of the same vessels by three expert readers. Manual and automated segmentations of 168 blood vessels from 34 B-scans were analyzed with respect to the deviations in the mean Euclidean distance and surface area. The mean Euclidean distance between the automatically and manually segmented contours (on average 4.0 pixels respectively 20 m against all three experts) was within the range of the manually marked contours among the three readers (approximately 3.8 pixels respectively 18 m for all experts). The area deviations between the automated and manual segmentation also lie within the range of the area deviations among the 3 clinical experts. Intra reader variability for the experts was between 0.9 and 0.94. We conclude that the automated segmentation approach is able to segment blood vessels with comparable accuracy as expert readers and will provide a useful tool in vessel analysis of whole C-scans, and in particular in multicenter trials. PMID:22808422

Pilch, Matthus; Wenner, Yaroslava; Strohmayr, Elisabeth; Preising, Markus; Friedburg, Christoph; Meyer zu Bexten, Erdmuthe; Lorenz, Birgit; Stieger, Knut

2012-01-01

142

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

NASA Technical Reports Server (NTRS)

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."

Parsons-Wingerter, Patricia A.

2003-01-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

144

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

145

Proteomic Profiling of Tissue-Engineered Blood Vessel Walls Constructed by Adipose-Derived Stem Cells  

PubMed Central

Adipose-derived stem cells (ASCs) can differentiate into smooth muscle cells and have been engineered into elastic small diameter blood vessel walls in vitro. However, the mechanisms involved in the development of three-dimensional (3D) vascular tissue remain poorly understood. The present study analyzed protein expression profiles of engineered blood vessel walls constructed by human ASCs using methods of two-dimensional gel electrophoresis (2DE) and mass spectrometry (MS). These results were compared to normal arterial walls. A total of 170115 and 126526 protein spots from normal and engineered blood vessel wall extractions were detected by 2DE, respectively. A total of 20 spots with at least 2.0-fold changes in expression were identified, and 38 differently expressed proteins were identified by 2D electrophoresis and ion trap MS. These proteins were classified into seven functional categories: cellular organization, energy, signaling pathway, enzyme, anchored protein, cell apoptosis/defense, and others. These results demonstrated that 2DE, followed by ion trap MS, could be successfully utilized to characterize the proteome of vascular tissue, including tissue-engineered vessels. The method could also be employed to achieve a better understanding of differentiated smooth muscle protein expression in vitro. These results provide a basis for comparative studies of protein expression in vascular smooth muscles of different origin and could provide a better understanding of the mechanisms of action needed for constructing blood vessels that exhibit properties consistent with normal blood vessels. PMID:22963350

Wang, Chen; Guo, Fangfang; Zhou, Heng; Zhang, Yun; Xiao, Zhigang

2013-01-01

146

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

PubMed Central

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

Fung, Y C; Liu, S Q

1995-01-01

147

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

E-print Network

Cellular/Molecular Glial Cells Dilate and Constrict Blood Vessels: A Mechanism of Neurovascular, Minneapolis, Minnesota 55455 Neuronal activity evokes localized changes in blood flow. Although this response cells to neurovascular coupling in the acutely isolated mammalian retina. We found that light

Newman, Eric A.

148

Determination of Blood Vessel Dimension Us ing Field Programmable Gate Array (FPGA)  

Microsoft Academic Search

An attempt has been made to propose a highly automated method for the determination of instantaneous blood flow rate of the heart. The method uses an image processing scheme to compute the diameters of the blood vessels. Code has been written in Verilog Hardware De- scriptive Language and is then simulated using Modelsim software. The results computed are compared with

Anita Agrawal; A. A. Ghatol; Shashwat Purushottam; Himanshu Srivastav

2009-01-01

149

Signaling Required for Blood Vessel Maintenance: Molecular Basis and Pathological Manifestations  

PubMed Central

As our understanding of molecular mechanisms leading to vascular formation increases, vessel maintenance including stabilization of new vessels and prevention of vessel regression began to be considered as an active process that requires specific cellular signaling. While signaling pathways such as VEGF, FGF, and angiopoietin-Tie2 are important for endothelial cell survival and junction stabilization, PDGF and TGF-? signaling modify mural cell (vascular smooth muscle cells and pericytes) functions, thus they fortify vessel integrity. Breakdown of these signaling systems results in pathological hyperpermeability and/or genetic vascular abnormalities such as vascular malformations, ultimately progressing to hemorrhage and edema. Hence, blood vessel maintenance is fundamental to controlling vascular homeostasis and tissue functions. This paper discusses signaling pathways essential for vascular maintenance and clinical conditions caused by deterioration of vessel integrity. PMID:22187650

Murakami, Masahiro

2012-01-01

150

Retinal hyperaemia-related blood vessel artifacts are relevant to automated OCT layer segmentation.  

PubMed

A frequently observed local measurement artifact with spectral domain OCT is caused by the void signal of the retinal vasculature. This study investigated the effect of suppression of blood vessel artifacts with and without retinal hyperaemia. Spectral domain OCT scans, centred on the optic nerve head, were performed in 46 healthy subjects (92 eyes). Baseline scans were made during rest, while for the follow-up scan, 23 subjects (50 %) performed strenuous physical exercise. Systemic and retinal hyperaemia were quantified. Quantification of retinal nerve fibre layer (RNFL) thickness was performed with and without suppression of retinal blood vessel artifacts. The potential systematic effect on RNFL thickness measurements was analysed using Bland-Altman plots. At baseline (no retinal hyperaemia), there was a systematic difference in RNFL thickness (3.4 ?m, limits of agreement -0.9 to 7.7) with higher values if blood vessel artifacts were not suppressed. There was significant retinal hyperaemia in the exercise group (p < 0.0001). Baseline thickness increased from 93.18 to 93.83 ?m (p < 0.05) in the exercise group using the algorithm with blood vessel artifact suppression, but no significant changes were observed using the algorithm without blood vessel artifact suppression. Retinal hyperaemia leads to blood vessel artifacts which are relevant to the precision of OCT layer segmentation algorithms. The two algorithms investigated in this study can not be used interchangeably. The algorithm with blood vessel artifact suppression was more sensitive in detecting small changes in RNFL thickness. This may be relevant for the use of OCT in a range of neurodegenerative diseases were only a small degree of retinal layer atrophy have been found so far. PMID:24390200

Balk, L J; Mayer, M; Uitdehaag, B M J; Petzold, A

2014-03-01

151

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

152

Blood vessel adaptation to gravity in a semi-arboreal snake  

NASA Technical Reports Server (NTRS)

The effects of vasoactive agonists on systemic blood vessels were examined with respect to anatomical location and gravity acclimation in the semi-arboreal snake, Elaphe Obsoleta. Major blood vessels were reactive to putative neurotransmitters, hormones or local factors in vessel specific patterns. Catecholamines, adenosine triphosphate, histamine and high potassium (80 mM) stimulated significantly greater tension per unit vessel mass in posterior than anterior arteries. Anterior vessels were significantly more sensitive to catecholamines than midbody and posterior vessels. Angiotensin II stimulated significantly greater tension in carotid artery than in midbody and posterior dorsal aorta. Arginine vasotocin strongly contracted the left and right aortic arches and anterior dorsal aorta. Veins were strongly contracted by catecholamines, high potassium and angiotensin II, but less so by adenosine triphosphate, arginine vasotocin and histamine. Precontracted vessel were relaxed by acetylcholine and sodium nitroprusside, but not by atrial natriuretic peptide or bradykinin. Chronic exposure of snakes to intermittent hypergravity stress ( + 1.5 Gz at tail) did not affect the majority of vessel responses. These data demonstrate that in vitro tension correlates with that catecholamines, as well as other agonists, are important in mediating vascular responses to gravitational stresses in snakes.

Conklin, D. J.; Lillywhite, H. B.; Olson, K. R.; Ballard, R. E.; Hargens, A. R.

1996-01-01

153

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

PubMed Central

Fluorescent nanoparticles (FNPs) which were injected into a tumor tissue flowed out through the blood and lymph vessels. The FNPs in blood vessels remained only in the order for few minutes while those in lymph vessels remained for a long time disappearing completely in 25 hours. We found a primo vessel inside a lymph vessel near a blood vessel, and FNPs remained in the primo vessel for longer than 25 hours. In addition, we examined in detail the residual time characteristics of lymph vessels because it could be useful in a future study of fluid dynamical comparison of the three conduits. These residual time characteristics of FNPs in the three kinds of vessels may have implications for the dynamics of nanoparticle drugs for cancer chemotherapy. PMID:23662147

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

2013-01-01

154

TOPAZ: a computer code for modeling heat transfer and fluid flow in arbitrary networks of pipes, flow branches, and vessels  

SciTech Connect

An overview of the computer code TOPAZ (Transient-One-Dimensional Pipe Flow Analyzer) is presented. TOPAZ models the flow of compressible and incompressible fluids through complex and arbitrary arrangements of pipes, valves, flow branches and vessels. Heat transfer to and from the fluid containment structures (i.e. vessel and pipe walls) can also be modeled. This document includes discussions of the fluid flow equations and containment heat conduction equations. The modeling philosophy, numerical integration technique, code architecture, and methods for generating the computational mesh are also discussed.

Winters, W.S.

1984-01-01

155

A novel scheme for nanoparticle steering in blood vessels using a functionalized magnetic field.  

PubMed

Magnetic drug targeting is a drug delivery approach in which therapeutic magnetizable particles are injected, generally into blood vessels, and magnets are then used to guide and concentrate them in the diseased target organ. Although many analytical, simulation, and experimental studies on capturing schemes for drug targeting have been conducted, there are few studies on delivering the nanoparticles to the target region. Furthermore, the sticking phenomenon of particles to vessels walls near the injection point, and far from the target region, has not been addressed sufficiently. In this paper, the sticking issue and its relationship to nanoparticle steering are investigated in detail using numerical simulations. For wide ranges of blood vessel size, blood velocity, particle size, and applied magnetic field, three coefficient numbers are uniquely generalized: vessel elongation, normal exit time, and force rate. With respect these new parameters, we investigated particle distribution trends for a Y-shaped channel and computed ratios of correctly guided particles and particles remaining in the vessel. We found that the sticking of particles to vessels occurred because of low blood flow velocity near the vessel walls, which is the main reason for low targeting efficiency when using a constant magnetic gradient. To reduce the sticking ratio of nanoparticles, we propose a novel field function scheme that uses a simple time-varying function to separate the particles from the walls and guide them to the target point. The capabilities of the proposed scheme were examined by several simulations of both Y-shaped channels and realistic three-dimensional (3-D) model channels extracted from brain vessels. The results showed a significant decrease in particle adherence to walls during the delivery stage and confirmed the effectiveness of the proposed magnetic field function method for steering nanoparticles for targeted drug delivery. PMID:25163053

Tehrani, Mohammad Dadkhah; Yoon, Jong-Hwan; Kim, Myeong Ok; Yoon, Jungwon

2015-01-01

156

COVERAGE OF BLOOD VESSELS BY ASTROCYTIC ENDFEET IS REDUCED IN MAJOR DEPRESSIVE DISORDER  

PubMed Central

Background According to clinical studies, depression and cerebrovascular disease influence each other. Despite this evidence, no studies have investigated the relationship between major depressive disorder (MDD) and cerebrovascular disease at the cellular level. Astrocytic processes are a crucial interface between blood vessels and neurons, and astrocyte density is reduced in MDD. This study investigated the coverage of vessels by astrocyte endfeet in the prefrontal cortex in MDD. Methods Thirteen pairs of MDD and non-psychiatric control subjects were used for double immunofluorescent staining and confocal image analysis. Frozen sections of gray matter from orbitofrontal area 47 and white matter from the ventro-medial prefrontal cortex were examined. Astrocytic processes (labeled with antibodies for aquaporin-4, AQP4 or glial fibrillary acidic protein, GFAP) were co-localized with blood vessels (labeled with an antibody to collagen IV) to measure the coverage of vessel walls by astrocyte processes. Results The coverage of blood vessels by endfeet of AQP4-immunoreactive (IR) astrocytes was significantly reduced by 50 percent in subjects with MDD as compared to controls (ANCOVA: F(1,23)=5.161, p=0.033). This difference was detected in orbitofrontal gray matter but not in white matter. Conversely, the coverage of vessels by GFAP-IR processes did not significantly differ between the groups. Conclusions A significant reduction in the coverage of gray matter vessels by AQP4-IR astrocyte processes in MDD suggests alterations in AQP4 functions such as regulation of water homeostasis, blood flow, glucose transport and metabolism, the blood brain barrier, glutamate turnover and synaptic plasticity. PMID:23146357

Rajkowska, Grazyna; Hughes, Jonathan; Stockmeier, Craig A.; Miguel-Hidalgo, Jose Javier; Maciag, Dorota

2012-01-01

157

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

PubMed Central

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

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

158

MD Anderson study finds blood vessel cells coax colorectal cancer cells into more dangerous state  

Cancer.gov

Blood vessels that supply oxygen and nutrients to tumors can also deliver something else -- a signal that strengthens nearby cancer cells, making them more resistant to chemotherapy, more likely to spread to other organs and more lethal, scientists at The University of Texas MD Anderson Cancer Center report online in Cancer Cell. Working in human colorectal cancer cell lines and tumor samples, as well as mouse models, the researchers found that endothelial cells, which line the inside of blood vessels, can trigger changes in cancer cells without even coming into direct contact with them.

159

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

NASA Astrophysics Data System (ADS)

The rolling massage manipulation is a classic Chinese Medical Massage, which is a nature therapy in eliminating many diseases. Here, the effect of the rolling massage on the cavity flows in blood vessel under the rolling manipulation is studied by the lattice Boltzmann simulation. The simulation results show that the vortex flows are fully disturbed by the rolling massage. The flow behavior depends on the rolling velocity and the rolling depth. Rolling massage has a better effect on the flows in the cavity than that of the flows in a planar blood vessel. The result is helpful to understand the mechanism of the massage and develop the rolling techniques.

Yi, Hou Hui

160

The behaviors of ferromagnetic nano-particles in and around blood vessels under applied magnetic fields  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

161

On the Small Vessel Detection in High Resolution Retinal Images  

Microsoft Academic Search

In this paper, we proposed a new scheme for detection of small blood vessels in retinal images. A novel filter called Gabor variance filter and a modified histogram equalization technique are developed to enhance the contrast between vessels and background. Vessel segmentation is then performed on the enhanced map using thresholding and branch pruning based on the vessel structures. The

Ming Zhang; Di Wu; Jyh-Charn Liu

2005-01-01

162

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

Background Magnetite used in an 8-MHz radiofrequency (RF) capacitive heating device can increase the temperature of a specific site up to 45C. 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 30min at 45C. After heating, a histological study for injury to the blood vessels was performed. Results The inner membrane temperature did not reach 45C 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

2014-01-01

163

[Contrast medium enhanced MR angiography of peripheral blood vessels].  

PubMed

Currently 2D time-of-flight MR angiography (MRA) is most commonly used for the evaluation of the extremities. The major limitation is their susceptibility to signal loss from intravoxel phase dispersion. This leads to overestimation in the grading of stenoses. Further difficulties are motion artifacts and the limited spatial resolution. Phase-contrast MRA is increasingly used. However, further studies are required to verify its diagnostic potential. MRA technology continues to advance rapidly. Stronger gradient fields, shorter echo times and high resolution surface coils are developed. Contrast medium can be applied under standardized conditions with MR compatible power injectors. In phantom studies, the contrast-enhanced gradient echo sequences show reduced phase dispersion, resulting in an improved grading of stenoses. Initial patient studies underline these findings. Contrast-enhanced MR angiography has the potential to replace invasive arteriography in the evaluation of peripheral arterial vessels in the near future. PMID:9340692

Vosshenrich, R; Kopka, L; Grabbe, E

1997-07-01

164

Cellular and molecular mechanisms underlying blood vessel lumen formation  

PubMed Central

The establishment of a functional vascular system requires multiple complex steps throughout embryogenesis, from endothelial cell (EC) specification to vascular patterning into venous and arterial hierarchies. Following the initial assembly of ECs into a network of cord-like structures, vascular expansion and remodeling occur rapidly through morphogenetic events including vessel sprouting, fusion, and pruning. In addition, vascular morphogenesis encompasses the process of lumen formation, critical for the transformation of cords into perfusable vascular tubes. Studies in mouse, zebrafish, frog, and human endothelial cells have begun to outline the cellular and molecular requirements underlying lumen formation. Although the lumen can be generated through diverse mechanisms, the coordinated participation of multiple conserved molecules including transcription factors, small GTPases, and adhesion and polarity proteins remains a fundamental principle, leading us closer to a more thorough understanding of this complex event. PMID:24323945

Charpentier, Marta S.; Conlon, Frank L.

2014-01-01

165

Hepoxilins sensitize blood vessels to noradrenaline--stereospecificity of action.  

PubMed Central

1. The vascular activity of two stereoisomers of hepoxilin A3 (HxA3) (8R and 8S) and of its glutathione conjugate, hepoxilin A3-C (HxA3-C) (8R and 8S), was investigated on rat helicoidal strips of thoracic aorta and longitudinal strips of portal vein. 2. Neither of the hepoxilins tested had a direct effect on the tone of the aortic strip or on the spontaneous contractions of the portal vein. However, the noradrenaline (NA)-induced response of these vessels, as expressed by the dose required for half maximal contraction, (EC50) was greater in HxA3 (8S)- and HxA3-C (8R)-treated aorta. Increased frequency and strength of spontaneous contractions of the portal vein were detected at lower concentrations of NA in the presence of hepoxilins. 3. The threshold dose for both hepoxilins was 10(-8) M and their effect was not dose-related beyond 10(-8) M. The effect of hepoxilin appeared after a 45 min incubation period and could be observed even if the compounds were washed out after 15 min. 4. Stereochemical specificity was observed. The 8S isomer of HxA3 was active in potentiating the NA-induced contraction of these vessels while the 8R isomer was inactive. In contrast, the 8R isomer of HxA3-C was active while the 8S isomer was inactive. In both tissues, HxA3 (8S) was more potent than its glutathione conjugate, HxA3-C (8R). 5. In calcium-free buffer or in the presence of a calcium channel blocker (nifedipine 1 microM), no potentiation of NA-induced contraction by hepoxilins could be observed, suggesting the involvement of extracellular calcium in the actions of hepoxilins.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1559126

Laneuville, O.; Couture, R.; Pace-Asciak, C. R.

1992-01-01

166

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

167

Role of tissue factor in embryonic blood vessel development  

Microsoft Academic Search

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

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

1996-01-01

168

Polarized Monte Carlo simulation of blood vessel structure in colon tissue  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

169

Feasibility of Using the Marginal Blood Vessels as Reference Landmarks for CT Colonography  

PubMed Central

OBJECTIVE The purpose of this study was to show the spatial relationship of the colonic marginal blood vessels and the teniae coli on CT colonography (CTC) and the use of the marginal blood vessels for supine-prone registration of polyps and for determination of proper connectivity of collapsed colonic segments. MATERIALS AND METHODS We manually labeled the marginal blood vessels on 15 CTC examinations. Colon segmentation, centerline extraction, teniae detection, and teniae identification were automatically performed. For assessment of their spatial relationships, the distances from the marginal blood vessels to the three teniae coli and to the colon were measured. Student t tests (paired, two-tailed) were performed to evaluate the differences among these distances. To evaluate the reliability of the marginal vessels as reference points for polyp correlation, we analyzed 20 polyps from 20 additional patients who underwent supine and prone CTC. The average difference of the circumferential polyp position on the supine and prone scans was computed. Student t tests (paired, two-tailed) were performed to evaluate the supine-prone differences of the distance. We performed a study on 10 CTC studies from 10 patients with collapsed colonic segments by manually tracing the marginal blood vessels near the collapsed regions to resolve the ambiguity of the colon path. RESULTS The average distances ( SD) from the marginal blood vessels to the tenia mesocolica, tenia omentalis, and tenia libera were 20.1 3.1 mm (95% CI, 18.521.6 mm), 39.5 4.8 mm (37.142.0 mm), and 36.9 4.2 mm (34.839.1 mm), respectively. Pairwise comparison showed that these distances to the tenia libera and tenia omentalis were significantly different from the distance to the tenia mesocolica (p < 0.001). The average distance from the marginal blood vessels to the colon wall was 15.3 2.0 mm (14.216.3 mm). For polyp localization, the average difference of the circumferential polyp position on the supine and prone scans was 9.6 9.4 mm (5.513.7 mm) (p = 0.15) and expressed as a percentage of the colon circumference was 3.1% 2.0% (2.34.0%) (p = 0.83). We were able to trace the marginal blood vessels for 10 collapsed colonic segments and determine the paths of the colon in these regions. CONCLUSION The marginal blood vessels run parallel to the colon in proximity to the tenia mesocolica and enable accurate supine-prone registration of polyps and localization of the colon path in areas of collapse. Thus, the marginal blood vessels may be used as reference landmarks complementary to the colon centerline and teniae coli. PMID:24370165

Wei, Zhuoshi; Yao, Jianhua; Wang, Shijun; Liu, Jiamin; Dwyer, Andrew J.; Pickhardt, Perry J.; Nowinski, Wieslaw L.; Summers, Ronald M.

2015-01-01

170

A New Seeded Region Growing Technique for Retinal Blood Vessels Extraction  

PubMed Central

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

Sajadi, Atefeh Sadat; Sabzpoushan, Seyed Hojat

2014-01-01

171

Pulsed photothermal radiometry as a method for investigating blood vessel-like structures.  

PubMed

Pulsed photothermal radiometry (PPTR) is known to be suitable for in vivo investigations of tissue optical properties. As a noncontact, nondestructive method it is a very attractive candidate for on-line dosimetry of laser treatments that rely on thermal laser-tissue interaction. In this article, we extend the one-dimensional (1D) analytical formalism that has widely been used to describe PPTR signals to a two-dimensional treatment of a simplified model of a blood vessel. This approach leads to quantitative description of a PPTR signal that, unlike in an 1D treatment, not only shows changes in time, but also varies in space. Using this approach, we are able to gain instructive understanding on how target characteristics of a blood vessel-like structure influence such a spatiotemporal PPTR signal. Likewise, the ability of extracting target features from those measurements is evaluated. Subsequently, we present experimental realization of the idealized model of a blood vessel as used in our theory. Comparison of actual PPTR measurements with theoretical predictions allow vessel localization laterally and in depth. Using our setup, we furthermore demonstrate the influence of flow inside the vessel on the measured signal. PMID:11375732

Schmitz, C H; Oberheide, U; Lohmann, S; Lubatschowski, H; Ertmer, W

2001-04-01

172

Birc2 (cIap1) regulates endothelial cell integrity and blood vessel homeostasis.  

PubMed

Integrity of the blood vessel wall is essential for vascular homeostasis and organ function. A dynamic balance between endothelial cell survival and apoptosis contributes to this integrity during vascular development and pathological angiogenesis. The genetic and molecular mechanisms regulating these processes in vivo are still largely unknown. Here, we show that Birc2 (also known as cIap1) is essential for maintaining endothelial cell survival and blood vessel homeostasis during vascular development. Using a forward-genetic approach, we identified a zebrafish null mutant for birc2, which shows severe hemorrhage and vascular regression due to endothelial cell integrity defects and apoptosis. Using genetic and molecular approaches, we show that Birc2 positively regulates the formation of the TNF receptor complex I in endothelial cells, thereby promoting NF-kappaB activation and maintaining vessel integrity and stabilization. In the absence of Birc2, a caspase-8-dependent apoptotic program takes place that leads to vessel regression. Our findings identify Birc2 and TNF signaling components as critical regulators of vascular integrity and endothelial cell survival, thereby providing an additional target pathway for the control of angiogenesis and blood vessel homeostasis during embryogenesis, regeneration and tumorigenesis. PMID:17934460

Santoro, Massimo M; Samuel, Temesgen; Mitchell, Tracy; Reed, John C; Stainier, Didier Y R

2007-11-01

173

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

PubMed Central

Mechanical models have potential to guide the development and use of engineered blood vessels as well as other engineered tissues. This paper presents a microstructurally motivated, pseudoelastic, mechanical model of the biaxial mechanics of engineered vessels in the physiologic pressure range. The model incorporates experimentally measured densities and alignments of engineered collagen. Specifically, these microstructural and associated mechanical inputs were measured directly from engineered blood vessels that were cultured over periods of 57.5 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

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

174

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)

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.

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

2007-03-01

175

An Important Role of Blood and Lymphatic Vessels in Inflammation and Allergy  

PubMed Central

Angiogenesis and lymphangiogenesis, the growth of new vessels from preexisting ones, have received increasing interest due to their role in tumor growth and metastatic spread. However, vascular remodeling, associated with vascular hyperpermeability, is also a key feature of many chronic inflammatory diseases including asthma, atopic dermatitis, psoriasis, and rheumatoid arthritis. The major drivers of angiogenesis and lymphangiogenesis are vascular endothelial growth factor- (VEGF-)A and VEGF-C, activating specific VEGF receptors on the lymphatic and blood vascular endothelium. Recent experimental studies found potent anti-inflammatory responses after targeted inhibition of activated blood vessels in models of chronic inflammatory diseases. Importantly, our recent results indicate that specific activation of lymphatic vessels reduces both acute and chronic skin inflammation. Thus, antiangiogenic and prolymphangiogenic therapies might represent a new approach to treat chronic inflammatory disorders, including those due to chronic allergic inflammation. PMID:23431319

Zgraggen, Silvana; Ochsenbein, Alexandra M.; Detmar, Michael

2013-01-01

176

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

Microsoft Academic Search

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

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

2000-01-01

177

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

Microsoft Academic Search

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

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

2007-01-01

178

Measurement of streaming potentials of mammalian blood vessels, aorta and vena cava, in vivo.  

PubMed

Attempts to measure streaming potentials in large rabbit blood vessels in vivo have been carried out. Streaming potentials, V(89), were measured by the introduction of microelectrodes through the wall of the blood vessel at separations greater than 1 cm. The outputs from these electrodes fed through calomel cells were amplified and recorded directly by using an Electronics for Medicine photorecorder (White Plains, N. Y.). "Effective streaming currents" were determined by running the output through a low impedence galvanometer while simultaneously measuring the resistance of the circuit V(8) were, therefore, calculated from two measurements and compared. Flow through vessels studied was measured using two different electromagnetic flowmeters. The results indicate that V(8) present in both aorta and vena cava are of the order of 5 to 10 mv. By using the Helmholtz-Smoluchowski equation into which flow was reintegrated, the numbers yield zeta potentials approximating 0.1 to 0.4 v in both aorta and vena cava. This number approaches the apparent upper limit for zeta (actually "interfacial potentials") potentials in biological systems. The measured "i.f." potential is considered as the interreaction of several physical and metabolic factors operating at the blood intimal interface. The polarity of the potential suggests that the interface is negative with respect to the blood flowing through the vessel. Interfacial potential and related V(8) are discussed in terms of their possible importance as a mechanism for maintaining vascular homeostasis in the living animal. PMID:5970567

Sawyer, P N; Himmelfarb, E; Lustrin, I; Ziskind, H

1966-09-01

179

Mass General study finds normalizing tumor blood vessels improves delivery of only the smallest nanomedicines  

Cancer.gov

Combining two strategies designed to improve the results of cancer treatment antiangiogenesis drugs and nanomedicines may only be successful if the smallest nanomedicines are used. A new study from Massachusetts General Hospital researchers, appearing in Nature Nanotechnology, finds that normalizing blood vessels within tumors, which improves the delivery of standard chemotherapy drugs, can block the delivery of larger nanotherapy molecules.

180

Regional and developmental variations of blood vessel morphometry in the chick embryo chorioallantoic membrane  

Microsoft Academic Search

Avian eggs contain all the necessary materials for embryonic development except for oxygen, which diffuses in from the environment via pores in the hard, calcified eggshell to the chorioallantoic membrane (CAM), the respiratory organ, which is rich in blood vessels. An air cell is formed at the blunt pole of the egg between the two membranes of the eggshell and

Arava Reizis; Ilan Hammel; Amos Ar

2005-01-01

181

Podocytes in the blood vessel linings of Phoronis muelleri (Phoronida, Tentaculata).  

PubMed

In several metasomal blood vessels of Phoronis muelleri myofilament-containing podocytes are the predominatnt cell-type. In some regions the podocytes can build a labyrinth resembling e.g. the glomerular epithelium of Enteropneusta and the axial organ of Asteroidea. PMID:688346

Storch, V; Herrmann, K

1978-07-10

182

Podocytes in the blood vessel linings of Phoronis muelleri (Phoronida, Tentaculata)  

Microsoft Academic Search

In several metasomal blood vessels of Phoronis muelleri myofilament-containing podocytes are the predominant cell-type. In some regions the podocytes can build a labyrinth resembling e.g. the glomerular epithelium of Enteropneusta and the axial organ of Asteroidea.

V. Storch; K. Herrmann

1978-01-01

183

Gene transfer by viral vectors into blood vessels in a rat model of retinopathy of prematurity  

PubMed Central

AIMSTo test the feasibility of gene transfer into hyaloid blood vessels and into preretinal neovascularisation in a rat model of retinopathy of prematurity (ROP), using different viral vectors.?METHODSNewborn rats were exposed to alternating hypoxic and hyperoxic conditions in order to induce ocular neovascularisation (ROP rats). Adenovirus, herpes simplex, vaccinia, and retroviral (MuLV based) vectors, all carrying the ?galactosidase (?-gal) gene, were injected intravitreally on postnatal day 18(P18). Two sets of controls were also examined: P18 ROP rats injected with saline and P18 rats that were raised in room air before the viral vectors or saline were injected. Two days after injection, the rats were killed, eyes enucleated, and ?-gal expression was examined by X-gal staining in whole mounts and in histological sections.?RESULTSIntravitreal injection of the adenovirus and vaccinia vectors yielded marked ?-gal expression in hyaloid blood vessels in the rat ROP model. Retinal expression of ?-gal with these vectors was limited almost exclusively to the vicinity of the injection site. Injection of herpes simplex yielded a punctuate pattern of ?-gal expression in the retina but not in blood vessels. No significant ?-gal expression occurred in rat eyes injected with the retroviral vector.?CONCLUSIONSAdenovirus is an efficient vector for gene transfer into blood vessels in an animal model of ROP. This may be a first step towards utilising gene transfer as a tool for modulating ocular neovascularisation for experimental and therapeutic purposes.?? PMID:11466260

Chowers, I.; Banin, E.; Hemo, Y.; Porat, R.; Falk, H.; Keshet, E.; Pe'er, J.; Panet, A.

2001-01-01

184

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

E-print Network

at the highest optical energies; this provides a model for hemorrhage. (ii) Extravasation of blood components) An intravascular clot evolved when an extravasated vessel was further irradiated. Such clots dramatically impaired to extravasation of serum proteins into the cerebral space and brain antigens into the peripheral circulation

Cai, Long

185

Generation of Functional Blood Vessels from a Single c-kit+ Adult Vascular Endothelial Stem Cell  

PubMed Central

In adults, the growth of blood vessels, a process known as angiogenesis, is essential for organ growth and repair. In many disorders including cancer, angiogenesis becomes excessive. The cellular origin of new vascular endothelial cells (ECs) during blood vessel growth in angiogenic situations has remained unknown. Here, we provide evidence for adult vascular endothelial stem cells (VESCs) that reside in the blood vessel wall endothelium. VESCs constitute a small subpopulation within CD117+ (c-kit+) ECs capable of undergoing clonal expansion while other ECs have a very limited proliferative capacity. Isolated VESCs can produce tens of millions of endothelial daughter cells in vitro. A single transplanted c-kit-expressing VESC by the phenotype lin?CD31+CD105+Sca1+CD117+ can generate in vivo functional blood vessels that connect to host circulation. VESCs also have long-term self-renewal capacity, a defining functional property of adult stem cells. To provide functional verification on the role of c-kit in VESCs, we show that a genetic deficit in endothelial c-kit expression markedly decreases total colony-forming VESCs. In vivo, c-kit expression deficit resulted in impaired EC proliferation and angiogenesis and retardation of tumor growth. Isolated VESCs could be used in cell-based therapies for cardiovascular repair to restore tissue vascularization after ischemic events. VESCs also provide a novel cellular target to block pathological angiogenesis and cancer growth. PMID:23091420

Fang, Shentong; Wei, Jing; Pentinmikko, Nalle; Leinonen, Hannele; Salven, Petri

2012-01-01

186

Lasers in Surgery and Medicine 44:144151 (2012) Photocoagulation of Dermal Blood Vessels With Multiple  

E-print Network

Lasers in Surgery and Medicine 44:144­151 (2012) Photocoagulation of Dermal Blood Vessels- pared to SLP. The 5 Hz fr and the need for two pulses are achievable with modern laser technology, which and a decrease in perivascular nerve density [3­5]. The current treatment of choice for PWS is the pulsed dye

Choi, Bernard

187

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

Microsoft Academic Search

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

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

2003-01-01

188

Cell-demanded liberation of VEGF121 from fibrin implants induces local and controlled blood vessel growth.  

PubMed

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 activity. In this study, we present an engineered variant form of VEGF, alpha2PI1-8-VEGF121, that mimics this concept of matrix-binding and cell-mediated release by local cell-associated enzymatic activity, working in the surgically-relevant biological matrix fibrin. We show that matrix-conjugated alpha2PI1-8-VEGF121 is protected from clearance, contrary to native VEGF121 mixed into fibrin, which was completely released as a passive diffusive burst. Grafting studies on the embryonic chicken chorioallantoic membrane (CAM) and in adult mice were performed to assess and compare the quantity and quality of neovasculature induced in response to fibrin implants formulated with matrix-bound alpha2PI1-8-VEGF121 or native diffusible VEGF121. Our CAM measurements demonstrated that cell-demanded release of alpha2PI1-8-VEGF121 increases the formation of new arterial and venous branches, whereas exposure to passively released wild-type VEGF121 primarily induced chaotic changes within the capillary plexus. Specifically, our analyses at several levels, from endothelial cell morphology and endothelial interactions with periendothelial cells, to vessel branching and network organization, revealed that alpha2PI1-8-VEGF121 induces vessel formation more potently than native VEGF121 and that those vessels possess more normal morphologies at the light microscopic and ultrastructural level. Permeability studies in mice validated that vessels induced by alpha2PI1-8-VEGF121 do not leak. In conclusion, cell-demanded release of engineered VEGF121 from fibrin implants may present a therapeutically safe and practical modality to induce local angiogenesis. PMID:15044320

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

2004-04-30

189

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

PubMed Central

Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-?1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors inexpensive drugs with decades of safe use could be rapidly repurposed as cancer therapeutics. PMID:24084631

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

2013-01-01

190

Mosaic blood vessels in tumors: Frequency of cancer cells in contact with flowing blood  

PubMed Central

The presence of mosaic vessels in which both endothelial cells and tumor cells form the luminal surface has profound implications for metastasis, drug delivery, and antivascular therapy. Yet little is known of the frequency, and thus importance, of mosaic vessels in tumors. Using CD31 and CD105 to identify endothelial cells and endogenous green fluorescent protein labeling of tumor cells, we show that ?15% of perfused vessels of a colon carcinoma xenografted at two different sites in mice were mosaic vessels having focal regions where no CD31/CD105 immunoreactivity was detected and tumor cells appeared to contact the vessel lumen. These regions occupied ?25% of the perimeter of the mosaic vessels, or ?4% of the total vascular surface area in these colon carcinomas. In addition, we found similar numbers of mosaic vessels in human colon carcinoma biopsies. Our results are consistent with the observation that ?106 cells are shed daily per g of tumor. More importantly, our data offer a possible explanation for the antivascular effects of cytotoxic agents and suggest potential strategies for targeting the tumor vasculature. PMID:11121063

Chang, Yong S.; di Tomaso, Emmanuelle; McDonald, Donald M.; Jones, Rosemary; Jain, Rakesh K.; Munn, Lance L.

2000-01-01

191

Visualization of subsurface blood vessels by color Doppler optical coherence tomography in rats: before and after hemostatic therapy  

Microsoft Academic Search

Background: The ability to visualize subsurface blood vessels and measure flow may be useful in certain experimental and clinical settings. Methods: Color Doppler optical coherence tomography was used to visualize and measure blood flow in subsurface vessels in vivo in a rat skin flap model. Local hemostatic interventions (epinephrine or sclerosant injection, heat probe, and laser) were then applied and

Richard C. K. Wong; Siavash Yazdanfar; Joseph A. Izatt; Manish D. Kulkarni; Jennifer K. Barton; Ashley J. Welch; Joseph Willis; Michael V. Sivak

2002-01-01

192

Blood vessels surrounded by connective tissue (perivascular space) in the brain of Lepidosteus (Ganoidei) and some teleost fishes  

Microsoft Academic Search

Blood vessels surrounded by unusually wide perivascular spaces rich in connective tissue were observed in the brain of Lepidosteus (Ganoidei). Connective-tissue sheaths measuring up to 13 m in width enclose arterioles and venules (4070 m in diameter), and even capillaries may be encompassed by a cuff formed by collagen fibers. Blood vessels with wide perivascular spaces are mainly located in

G. Merker; A. Oksche; H. O. Hofer

1974-01-01

193

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

PubMed

It has been shown that tiny gas nanobubbles form spontaneously on a smooth hydrophobic surface submerged in water. These nanobubbles were shown to be the source of gas micronuclei from which bubbles evolved during decompression of silicon wafers. We suggest that the hydrophobic inner surface of blood vessels may be a site of nanobubble production. Sections from the right and left atria, pulmonary artery and vein, aorta, and superior vena cava of sheep (n=6) were gently stretched on microscope slides and exposed to 1013 kPa for 18 h. Hydrophobicity was checked in the six blood vessels by advancing contact angle with a drop of saline of 7119, with a maximum of about 1107 (meanSD). Tiny bubbles ~30 ?m in diameter rose vertically from the blood vessels and grew on the surface of the saline, where they were photographed. All of the blood vessels produced bubbles over a period of 80 min. The number of bubbles produced from a square cm was: in the aorta, 20.5; left atrium, 27.3; pulmonary artery, 17.9; pulmonary vein, 24.3; right atrium, 29.5; superior vena cava, 36.4. More than half of the bubbles were present for less than 2 min, but some remained on the saline-air interface for as long as 18 min. Nucleation was evident in both the venous (superior vena cava, pulmonary artery, right atrium) and arterial (aorta, pulmonary vein, left atrium) blood vessels. This newly suggested mechanism of nucleation may be the main mechanism underlying bubble formation on decompression. PMID:23624230

Arieli, R; Marmur, A

2013-08-01

194

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

PubMed

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=rholUmaxdmicroapp , in the neighborhood of 0.2, 2, and 200 are investigated. Here, rhol is the density of blood, Umax is the centerline velocity of the inlet Casson profile, d is the diameter of the vessel, and microapp 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), lambda , in the range 0.9< or =lambda< or =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

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

2008-09-01

195

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

196

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

PubMed

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

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

2014-12-28

197

Interactive 3D Analysis of Blood Vessel Trees and Collateral Vessel Volumes in Magnetic Resonance Angiograms in the Mouse Ischemic Hindlimb Model.  

PubMed

The quantitative analysis of blood vessel volumes from magnetic resonance angiograms (MRA) or ?CT images is difficult and time-consuming. This fact, when combined with a study that involves multiple scans of multiple subjects, can represent a significant portion of research time. In order to enhance analysis options and to provide an automated and fast analysis method, we developed a software plugin for the ImageJ and Fiji image processing frameworks that enables the quick and reproducible volume quantification of blood vessel segments. The novel plugin named Volume Calculator (VolCal), accepts any binary (thresholded) image and produces a three-dimensional schematic representation of the vasculature that can be directly manipulated by the investigator. Using MRAs of the mouse hindlimb ischemia model, we demonstrate quick and reproducible blood vessel volume calculations with 95 - 98% accuracy. In clinical settings this software may enhance image interpretation and the speed of data analysis and thus enhance intervention decisions for example in peripheral vascular disease or aneurysms. In summary, we provide a novel, fast and interactive quantification of blood vessel volumes for single blood vessels or sets of vessel segments with particular focus on collateral formation after an ischemic insult. PMID:24563682

Marks, Peter C; Preda, Marilena; Henderson, Terry; Liaw, Lucy; Lindner, Volkhard; Friesel, Robert E; Pinz, Ilka M

2013-10-31

198

Interactive 3D Analysis of Blood Vessel Trees and Collateral Vessel Volumes in Magnetic Resonance Angiograms in the Mouse Ischemic Hindlimb Model  

PubMed Central

The quantitative analysis of blood vessel volumes from magnetic resonance angiograms (MRA) or ?CT images is difficult and time-consuming. This fact, when combined with a study that involves multiple scans of multiple subjects, can represent a significant portion of research time. In order to enhance analysis options and to provide an automated and fast analysis method, we developed a software plugin for the ImageJ and Fiji image processing frameworks that enables the quick and reproducible volume quantification of blood vessel segments. The novel plugin named Volume Calculator (VolCal), accepts any binary (thresholded) image and produces a three-dimensional schematic representation of the vasculature that can be directly manipulated by the investigator. Using MRAs of the mouse hindlimb ischemia model, we demonstrate quick and reproducible blood vessel volume calculations with 95 98% accuracy. In clinical settings this software may enhance image interpretation and the speed of data analysis and thus enhance intervention decisions for example in peripheral vascular disease or aneurysms. In summary, we provide a novel, fast and interactive quantification of blood vessel volumes for single blood vessels or sets of vessel segments with particular focus on collateral formation after an ischemic insult. PMID:24563682

Marks, Peter C.; Preda, Marilena; Henderson, Terry; Liaw, Lucy; Lindner, Volkhard; Friesel, Robert E.; Pinz, Ilka M.

2014-01-01

199

Generation of functionally competent and durable engineered blood vessels from human induced pluripotent stem cells  

PubMed Central

Efficient generation of competent vasculogenic cells is a critical challenge of human induced pluripotent stem (hiPS) cell-based regenerative medicine. Biologically relevant systems to assess functionality of the engineered vessels in vivo are equally important for such development. Here, we report a unique approach for the derivation of endothelial precursor cells from hiPS cells using a triple combination of selection markersCD34, neuropilin 1, and human kinase insert domain-containing receptorand an efficient 2D culture system for hiPS cell-derived endothelial precursor cell expansion. With these methods, we successfully generated endothelial cells (ECs) from hiPS cells obtained from healthy donors and formed stable functional blood vessels in vivo, lasting for 280 d in mice. In addition, we developed an approach to generate mesenchymal precursor cells (MPCs) from hiPS cells in parallel. Moreover, we successfully generated functional blood vessels in vivo using these ECs and MPCs derived from the same hiPS cell line. These data provide proof of the principle that autologous hiPS cell-derived vascular precursors can be used for in vivo applications, once safety and immunological issues of hiPS-based cellular therapy have been resolved. Additionally, the durability of hiPS-derived blood vessels in vivo demonstrates a potential translation of this approach in long-term vascularization for tissue engineering and treatment of vascular diseases. Of note, we have also successfully generated ECs and MPCs from type 1 diabetic patient-derived hiPS cell lines and use them to generate blood vessels in vivo, which is an important milestone toward clinical translation of this approach. PMID:23861493

Samuel, Rekha; Daheron, Laurence; Liao, Shan; Vardam, Trupti; Kamoun, Walid S.; Batista, Ana; Buecker, Christa; Schfer, Richard; Han, Xiaoxing; Au, Patrick; Scadden, David T.; Duda, Dan G.; Fukumura, Dai; Jain, Rakesh K.

2013-01-01

200

[Based on blood vessel edge feature fundus fluorescein angiography image splicing].  

PubMed

According to fundus fluorescein angiography images characteristics, this paper proposes a feature based image mosaic vessel edge method. First, detect edge of blood vessels by carrying on the pretreatment to the fundus fluorescein angiography image in the foundation, wavelet edge detection algorithm. Then, the matching method based on chain code feature is described. Finally, a local area based on gray level information of the image fusion method is applied to angiographic image series. Data processing results show that the method can generate an ideal mosaic effect. PMID:21954575

Cui, Dong; Liu, Minmin; Guo, Yongxin; Jiao, Qing

2011-05-01

201

Analysis of blood flow in deformable vessels via a lattice Boltzmann approach  

NASA Astrophysics Data System (ADS)

In this paper, the lattice Boltzmann (LB) method is used in order to simulate non-Newtonian blood flows in deformable vessels. Casson's rheological model is adopted and a local correction to the relaxation time is implemented in order to modify the viscosity. The hyperelastic, hardening and anisotropic behavior of a flexible arterial wall is discussed and a closed-form solution is used to predict the deformed configuration of the vessel. A partitioned staggered-explicit strategy to couple the LB method and such analytical prediction is proposed.

de Rosis, Alessandro

2014-11-01

202

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

NASA Astrophysics Data System (ADS)

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

Sills, Tiffany M.; Hirschi, Karen K.

203

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

SciTech Connect

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

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

1984-06-01

204

Blood Vessels Pattern Heparan Sulfate Gradients between Their Apical and Basolateral Aspects  

PubMed Central

A hallmark of immune cell trafficking is directional guidance via gradients of soluble or surface bound chemokines. Vascular endothelial cells produce, transport and deposit either their own chemokines or chemokines produced by the underlying stroma. Endothelial heparan sulfate (HS) was suggested to be a critical scaffold for these chemokine pools, but it is unclear how steep chemokine gradients are sustained between the lumenal and ablumenal aspects of blood vessels. Addressing this question by semi-quantitative immunostaining of HS moieties around blood vessels with a pan anti-HS IgM mAb, we found a striking HS enrichment in the basal lamina of resting and inflamed post capillary skin venules, as well as in high endothelial venules (HEVs) of lymph nodes. Staining of skin vessels with a glycocalyx probe further suggested that their lumenal glycocalyx contains much lower HS density than their basolateral extracellular matrix (ECM). This polarized HS pattern was observed also in isolated resting and inflamed microvascular dermal cells. Notably, progressive skin inflammation resulted in massive ECM deposition and in further HS enrichment around skin post capillary venules and their associated pericytes. Inflammation-dependent HS enrichment was not compromised in mice deficient in the main HS degrading enzyme, heparanase. Our results suggest that the blood vasculature patterns steep gradients of HS scaffolds between their lumenal and basolateral endothelial aspects, and that inflammatory processes can further enrich the HS content nearby inflamed vessels. We propose that chemokine gradients between the lumenal and ablumenal sides of vessels could be favored by these sharp HS scaffold gradients. PMID:24465652

Stoler-Barak, Liat; Moussion, Christine; Shezen, Elias; Hatzav, Miki; Sixt, Michael; Alon, Ronen

2014-01-01

205

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot  

PubMed Central

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

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

2012-01-01

206

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

PubMed Central

Physiological as well as pathological blood vessel formation are fundamentally dependent on cell-matrix interaction. Integrins, a family of major cell adhesion receptors, play a pivotal role in development, maintenance, and remodeling of the vasculature. Cell migration, invasion, and remodeling of the extracellular matrix (ECM) are integrin-regulated processes, and the expression of certain integrins also correlates with tumor progression. Recent advances in the understanding of how integrins are involved in the regulation of blood vessel formation and remodeling during tumor progression are highlighted. The increasing knowledge of integrin function at the molecular level, together with the growing repertoire of integrin inhibitors which allow their selective pharmacological manipulation, makes integrins suited as potential diagnostic markers and therapeutic targets. PMID:21941547

Niland, Stephan; Eble, Johannes A.

2012-01-01

207

Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy.  

PubMed

Proliferative diabetic retinopathy can lead to blindness. However, early recognition allows appropriate, timely intervention. Fluorescein-labeled retinal blood vessels of 27 digital images were automatically segmented using the Gabor wavelet transform and classified using traditional features such as area, perimeter, and an additional five morphological features based on the derivatives-of-Gaussian wavelet-derived data. Discriminant analysis indicated that traditional features do not detect early proliferative retinopathy. The best single feature for discrimination was the wavelet curvature with an area under the curve (AUC) of 0.76. Linear discriminant analysis with a selection of six features achieved an AUC of 0.90 (0.73-0.97, 95% confidence interval). The wavelet method was able to segment retinal blood vessels and classify the images according to the presence or absence of proliferative retinopathy. PMID:17429492

Jelinek, Herbert F; Cree, Michael J; Leandro, Jorge J G; Soares, Joo V B; Cesar, Roberto M; Luckie, A

2007-05-01

208

Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy  

NASA Astrophysics Data System (ADS)

Proliferative diabetic retinopathy can lead to blindness. However, early recognition allows appropriate, timely intervention. Fluorescein-labeled retinal blood vessels of 27 digital images were automatically segmented using the Gabor wavelet transform and classified using traditional features such as area, perimeter, and an additional five morphological features based on the derivatives-of-Gaussian wavelet-derived data. Discriminant analysis indicated that traditional features do not detect early proliferative retinopathy. The best single feature for discrimination was the wavelet curvature with an area under the curve (AUC) of 0.76. Linear discriminant analysis with a selection of six features achieved an AUC of 0.90 (0.73-0.97, 95% confidence interval). The wavelet method was able to segment retinal blood vessels and classify the images according to the presence or absence of proliferative retinopathy.

Jelinek, Herbert F.; Cree, Michael J.; Leandro, Jorge J. G.; Soares, Joo V. B.; Cesar, Roberto M.; Luckie, A.

2007-05-01

209

Accurate measurement of blood vessel depth in port wine stained human skin in vivo using pulsed photothermal radiometry.  

PubMed

We report on application of pulsed photothermal radiometry (PPTR) to determine the depth of port wine stain (PWS) blood vessels in human skin. When blood vessels are deep in the PWS skin (>100 microm), conventional PPTR depth profiling can be used to determine PWS depth with sufficient accuracy. When blood vessels are close or partially overlap the epidermal melanin layer, a modified PPTR technique using two-wavelength (585 and 600 nm) excitation is a superior method to determine PWS depth. A direct difference approach in which PWS depth is determined from a weighted difference of temperature profiles reconstructed independently from two-wavelength excitation is demonstrated to be appropriate for a wider range of PWS patients with various blood volume fractions, blood vessel sizes, and depth distribution. The most superficial PWS depths determined in vivo by PPTR are in good agreement with those measured using optical Doppler tomography (ODT). PMID:15447017

Li, Bincheng; Majaron, Boris; Viator, John A; Milner, Thomas E; Chen, Zhongping; Zhao, Yonghua; Ren, Hongwu; Nelson, J Stuart

2004-01-01

210

An Experimental Study to Replace the Thoracic Descending Aorta for Pigs with a Self-Made Sutureless Blood Vessel  

PubMed Central

To simplify the procedure of blood vessel replacement operation and shorten the vascular anastomosis time, we developed a special artificial blood vessel which can be connected to native blood vessels without suture. The self-made sutureless blood vessel (SMSBV) was made from two titanium connectors and a Gore-Tex graft. To investigate blood compatibility and histocompatibility of the SMSBV, we carried thoracic descending aorta replacement using either SMSBV or Gore-Tex, respectively, in pigs. The aortic clamp time and the operative blood loss in the experimental group (using SMSBV) were less than those in the control group (using Gore-Tex). The whole blood hematocrit, platelet count, plasma soluble P-selectin, plasma free hemoglobin, and interleukins 2, 6 at each time point were not different significantly between the two groups. Light microscopy and transmission electron microscopy examination showed there were layers of vascular smooth muscle cells and endothelial cells adhered in the inner wall of artificial blood vessel without any signs of thrombosis. Based on the result, we have drawn the conclusion that the application of SMSBV can significantly shorten the vascular anastomosis time, reduce operative blood loss, and show good blood and tissue compatibility. PMID:24696856

Song, Fenglin; Zhou, Wenwu; Tang, Tao; Li, Xiaobing; Wu, Xiaoming; Yang, Jinfu

2014-01-01

211

Platelet Motion near a Vessel Wall or Thrombus Surface in Two-Dimensional Whole Blood Simulations  

PubMed Central

Computational simulations using a two-dimensional lattice-Boltzmann immersed boundary method were conducted to investigate the motion of platelets near a vessel wall and close to an intravascular thrombus. Physiological volume fractions of deformable red blood cells and rigid platelet-size elliptic particles were studied under arteriolar flow conditions. Tumbling of platelets in the red-blood-cell depleted zone near the vessel walls was strongly influenced by nearby red blood cells. The thickness of the red-blood-cell depleted zone was greatly reduced near a thrombus, and platelets in this zone were pushed close to the surface of the thrombus to distances that would facilitate their cohesion to it. The distance, nature, and duration of close platelet-thrombus encounters were influenced by the porosity of the thrombus. The strong influence on platelet-thrombus encounters of red-blood-cell motion and thrombus porosity must be taken into account to understand the dynamics of platelet attachment to a growing thrombus. PMID:23601323

Skorczewski, Tyler; Erickson, LindsayCrowl; Fogelson, Aaron L.

2013-01-01

212

Knowledge management in image-based analysis of blood vessel structures  

Microsoft Academic Search

We have detected the lack of a widely accepted knowledge representation model in the area of Blood Vessel analysis. We find\\u000a that such a tool is needed for the future development of the field and our own research efforts. It will allow easy reuse\\u000a of software pieces through appropriate abstractions, facilitating the development of innovative methods, procedures and applications.\\u000a We

Ivn Maca; Manuel Graa; Celine Paloc

213

Lymphatic and blood vessels in basal and triple-negative breast cancers: characteristics and prognostic significance  

Microsoft Academic Search

Basal and triple-negative breast cancer phenotypes are characterised by unfavourable biological behaviour and outcome. Although certain studies have examined their pathological and molecular profile, the vascular characteristics of lymphatic and blood vessels have not been examined. Immunohistochemical staining with podoplanin, CD34 and CD31 was used to examine lymphatic and microvessel density, as well as vascular invasion in 197 basal-like and

Rabab A A Mohammed; Ian O Ellis; Ali M Mahmmod; E Claire Hawkes; Andrew R Green; Emad A Rakha; Stewart G Martin

2011-01-01

214

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

Cancer.gov

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

215

[Thrombosis of an extraspermatic blood vessel--first description as a cause of acute scrotum].  

PubMed

Testicular torsion is a well known emergency situation in clinical urology. Usually cases with torsion of the testis, epididimis or Morgagni's hydatid present for operative emergency procedures due to an "acute scrotum". Also Amyand's hernia, anterior wall abscess, tumours of the testis or cholesterol granulomas have been described as mimicking a testicular torsion. We present the first case of thrombosis of an extraspermatic blood vessel as an unusual cause of an acute scrotum in 15-year-old boy. PMID:23712278

Wiedemann, A; Maykan, R; Bongert, M; Fsgen, I

2013-05-01

216

Stanford University researchers find that dual-action protein better restricts blood vessel formation:  

Cancer.gov

In a paper published online Aug. 8 in the Proceedings of the National Academy of Sciences, researchers at Stanford University describe the creation of a new type of engineered protein that is significantly more effective at preventing the formation of blood vessels by targeting not one, but two of the chemical receptors that control the creation of new capillaries -- a process known as angiogenesis. The study shows that the new protein blocks both receptors.

217

Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy  

Microsoft Academic Search

Proliferative diabetic retinopathy can lead to blindness. However, early recognition allows appropriate, timely intervention. Fluorescein-labeled retinal blood vessels of 27 digital images were automatically segmented using the Gabor wavelet transform and classified using traditional features such as area, perimeter, and an additional five morphological features based on the derivatives-of-Gaussian wavelet-derived data. Discriminant analysis indicated that traditional features do not detect

Herbert F. Jelinek; Michael J. Cree; Jorge J. G. Leandro; Joo V. B. Soares; Roberto M. Cesar; A. Luckie

2007-01-01

218

Context-Dependent Segmentation of Retinal Blood Vessels Using Hidden Markov Models  

Microsoft Academic Search

Hidden Markov Models (HMMs) have proven valuable in segmentation of brain MR images. Here, a combination of HMMs-based segmentation\\u000a and morphological and spatial image processing techniques is proposed for the segmentation of retinal blood vessels in optic\\u000a fundus images. First the image is smoothed and the result is subtracted from the green channel image to reduce the background\\u000a variations. After

Amir Pourmorteza; Seyed Hamid Reza Tofighi; Alireza Roodaki; Ashkan Yazdani; Hamid Soltanian-Zadeh

219

Automated Fluorescence as a System to Assist the Diagnosis of Retinal Blood Vessel Leakage  

Microsoft Academic Search

Leakage in retinal blood vessel may cause retinal edema which is a sign of diabetic retinopathy. Diabetic retinopathy is a\\u000a severe and widely spread eye disease which can be regarded as manifestation of diabetes on the retina. So far the most effective\\u000a diagnosis for this eye disease is early detection through FFA (Fluorescence Fundus Angiography) regular screening that can\\u000a lead

Vanya Vabrina Valindria; Tati L. R. Mengko; Iwan Sovani

220

Schlemm's Canal Is a Unique Vessel with a Combination of Blood Vascular and Lymphatic Phenotypes that Forms by a Novel Developmental Process  

PubMed Central

Schlemm's canal (SC) plays central roles in ocular physiology. These roles depend on the molecular phenotypes of SC endothelial cells (SECs). Both the specific phenotype of SECs and development of SC remain poorly defined. To allow a modern and extensive analysis of SC and its origins, we developed a new whole-mount procedure to visualize its development in the context of surrounding tissues. We then applied genetic lineage tracing, specific-fluorescent reporter genes, immunofluorescence, high-resolution confocal microscopy, and three-dimensional (3D) rendering to study SC. Using these techniques, we show that SECs have a unique phenotype that is a blend of both blood and lymphatic endothelial cell phenotypes. By analyzing whole mounts of postnatal mouse eyes progressively to adulthood, we show that SC develops from blood vessels through a newly discovered process that we name canalogenesis. Functional inhibition of KDR (VEGFR2), a critical receptor in initiating angiogenesis, shows that this receptor is required during canalogenesis. Unlike angiogenesis and similar to stages of vasculogenesis, during canalogenesis tip cells divide and form branched chains prior to vessel formation. Differing from both angiogenesis and vasculogenesis, during canalogenesis SECs express Prox1, a master regulator of lymphangiogenesis and lymphatic phenotypes. Thus, SC development resembles a blend of vascular developmental programs. These advances define SC as a unique vessel with a combination of blood vascular and lymphatic phenotypes. They are important for dissecting its functions that are essential for ocular health and normal vision. PMID:25051267

Kizhatil, Krishnakumar; Ryan, Margaret; Marchant, Jeffrey K.; Henrich, Stephen; John, Simon W. M.

2014-01-01

221

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

PubMed

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

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

2011-11-01

222

Aldehyde dehydrogenase-independent bioactivation of nitroglycerin in porcine and bovine blood vessels  

PubMed Central

The vascular bioactivation of the antianginal drug nitroglycerin (GTN), yielding 1,2-glycerol dinitrate and nitric oxide or a related activator of soluble guanylate cyclase, is catalyzed by aldehyde dehydrogenase-2 (ALDH2) in rodent and human blood vessels. The essential role of ALDH2 has been confirmed in many studies and is considered as general principle of GTN-induced vasodilation in mammals. However, this view is challenged by an early report showing that diphenyleneiodonium, which we recently characterized as potent ALDH2 inhibitor, has no effect on GTN-induced relaxation of bovine coronary arteries (De La Lande et al., 1996). We investigated this issue and found that inhibition of ALDH2 attenuates GTN-induced coronary vasodilation in isolated perfused rat hearts but has no effect on relaxation to GTN of bovine and porcine coronary arteries. This observation is explained by low levels of ALDH2 protein expression in bovine coronary arteries and several types of porcine blood vessels. ALDH2 mRNA expression and the rates of GTN denitration were similarly low, excluding a significant contribution of ALDH2 to the bioactivation of GTN in these vessels. Attempts to identify the responsible pathway with enzyme inhibitors did not provide conclusive evidence for the involvement of ALDH3A1, cytochrome P450, or GSH-S-transferase. Thus, the present manuscript describes a hitherto unrecognized pathway of GTN bioactivation in bovine and porcine blood vessels. If present in the human vasculature, this pathway might contribute to the therapeutic effects of organic nitrates that are not metabolized by ALDH2. PMID:25576686

Neubauer, Regina; Wlkart, Gerald; Opelt, Marissa; Schwarzenegger, Christine; Hofinger, Marielies; Neubauer, Andrea; Kollau, Alexander; Schmidt, Kurt; Schrammel, Astrid; Mayer, Bernd

2015-01-01

223

Aldehyde dehydrogenase-independent bioactivation of nitroglycerin in porcine and bovine blood vessels.  

PubMed

The vascular bioactivation of the antianginal drug nitroglycerin (GTN), yielding 1,2-glycerol dinitrate and nitric oxide or a related activator of soluble guanylate cyclase, is catalyzed by aldehyde dehydrogenase-2 (ALDH2) in rodent and human blood vessels. The essential role of ALDH2 has been confirmed in many studies and is considered as general principle of GTN-induced vasodilation in mammals. However, this view is challenged by an early report showing that diphenyleneiodonium, which we recently characterized as potent ALDH2 inhibitor, has no effect on GTN-induced relaxation of bovine coronary arteries (De La Lande et al., 1996). We investigated this issue and found that inhibition of ALDH2 attenuates GTN-induced coronary vasodilation in isolated perfused rat hearts but has no effect on relaxation to GTN of bovine and porcine coronary arteries. This observation is explained by low levels of ALDH2 protein expression in bovine coronary arteries and several types of porcine blood vessels. ALDH2 mRNA expression and the rates of GTN denitration were similarly low, excluding a significant contribution of ALDH2 to the bioactivation of GTN in these vessels. Attempts to identify the responsible pathway with enzyme inhibitors did not provide conclusive evidence for the involvement of ALDH3A1, cytochrome P450, or GSH-S-transferase. Thus, the present manuscript describes a hitherto unrecognized pathway of GTN bioactivation in bovine and porcine blood vessels. If present in the human vasculature, this pathway might contribute to the therapeutic effects of organic nitrates that are not metabolized by ALDH2. PMID:25576686

Neubauer, Regina; Wlkart, Gerald; Opelt, Marissa; Schwarzenegger, Christine; Hofinger, Marielies; Neubauer, Andrea; Kollau, Alexander; Schmidt, Kurt; Schrammel, Astrid; Mayer, Bernd

2015-02-15

224

Induction, differentiation, and remodeling of blood vessels after transplantation of Bcl-2-transduced endothelial cells.  

PubMed

Implants of collagen-fibronectin gels containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVECs) induce the formation of human endothelial cell (EC)/murine vascular smooth muscle cell (VSMC) chimeric vessels in immunodeficient mice. Microfil casting of the vasculature 60 d after implantation reveals highly branched microvascular networks within the implants that connect with and induce remodeling of conduit vessels arising from the abdominal wall circulation. Approximately 85% of vessels within the implants are lined by Bcl-2-positive human ECs expressing VEGFR1, VEGFR2, and Tie-2, but not integrin alpha(v)beta(3). The human ECs are seated on a well formed human laminin/collagen IV-positive basement membrane, and are surrounded by mouse VSMCs expressing SM-alpha actin, SM myosin, SM22alpha, and calponin, all markers of contractile function. Transmission electron microscopy identified well formed EC-EC junctions, chimeric arterioles with concentric layers of contractile VSMC, chimeric capillaries surrounded by pericytes, and chimeric venules. Bcl-2-HUVEC-lined vessels retain 70-kDa FITC-dextran, but not 3-kDa dextran; local histamine rapidly induces leak of 70-kDa FITC-dextran or India ink. As in skin, TNF induces E-selectin and vascular cell adhesion molecule 1 only on venular ECs, whereas intercellular adhesion molecule-1 is up-regulated on all human ECs. Bcl-2-HUVEC implants are able to engraft within and increase perfusion of ischemic mouse gastrocnemius muscle after femoral artery ligation. These studies show that cultured Bcl-2-HUVECs can differentiate into arterial, venular, and capillary-like ECs when implanted in vivo, and induce arteriogenic remodeling of the local mouse vessels. Our results support the utility of differentiated EC transplantation to treat tissue ischemia. PMID:15625106

Enis, David R; Shepherd, Benjamin R; Wang, Yinong; Qasim, Asif; Shanahan, Catherine M; Weissberg, Peter L; Kashgarian, Michael; Pober, Jordan S; Schechner, Jeffrey S

2005-01-11

225

Induction, differentiation, and remodeling of blood vessels after transplantation of Bcl-2-transduced endothelial cells  

PubMed Central

Implants of collagen-fibronectin gels containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVECs) induce the formation of human endothelial cell (EC)/murine vascular smooth muscle cell (VSMC) chimeric vessels in immunodeficient mice. Microfil casting of the vasculature 60 d after implantation reveals highly branched microvascular networks within the implants that connect with and induce remodeling of conduit vessels arising from the abdominal wall circulation. Approximately 85% of vessels within the implants are lined by Bcl-2-positive human ECs expressing VEGFR1, VEGFR2, and Tie-2, but not integrin ?v?3. The human ECs are seated on a well formed human laminin/collagen IV-positive basement membrane, and are surrounded by mouse VSMCs expressing SM-? actin, SM myosin, SM22?, and calponin, all markers of contractile function. Transmission electron microscopy identified well formed ECEC junctions, chimeric arterioles with concentric layers of contractile VSMC, chimeric capillaries surrounded by pericytes, and chimeric venules. Bcl-2-HUVEC-lined vessels retain 70-kDa FITC-dextran, but not 3-kDa dextran; local histamine rapidly induces leak of 70-kDa FITC-dextran or India ink. As in skin, TNF induces E-selectin and vascular cell adhesion molecule 1 only on venular ECs, whereas intercellular adhesion molecule-1 is up-regulated on all human ECs. Bcl-2-HUVEC implants are able to engraft within and increase perfusion of ischemic mouse gastrocnemius muscle after femoral artery ligation. These studies show that cultured Bcl-2-HUVECs can differentiate into arterial, venular, and capillary-like ECs when implanted in vivo, and induce arteriogenic remodeling of the local mouse vessels. Our results support the utility of differentiated EC transplantation to treat tissue ischemia. PMID:15625106

Enis, David R.; Shepherd, Benjamin R.; Wang, Yinong; Qasim, Asif; Shanahan, Catherine M.; Weissberg, Peter L.; Kashgarian, Michael; Pober, Jordan S.; Schechner, Jeffrey S.

2005-01-01

226

Drug that blocks blood vessel growth may be beneficial in treating AIDS-related Kaposis 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).

227

Dynamic quantitative intravital imaging of glioblastoma progression reveals a lack of correlation between tumor growth and blood vessel density.  

PubMed

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

Ricard, Clment; Stanchi, Fabio; Rodriguez, Thieric; Amoureux, Marie-Claude; Rougon, Genevive; Debarbieux, Franck

2013-01-01

228

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

E-print Network

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

Cremers, Daniel

229

Retinal vessels segmentation using supervised classifiers decisions fusion  

Microsoft Academic Search

Ophthalmology is a significant branch of the biomedical field which requires computer-aided automated techniques for pathology identification. Within this framework, an important concern is the accurate segmentation of the retinal blood vessels. A reference approach in the literature to this task consists in the classification of the pixels as vessels or non-vessels, using as discriminative features the green channel intensity,

Carmen Holbura; Mihaela Gordan; Aurel Vlaicu; Ioan Stoian; Dorina Capatana

2012-01-01

230

Three-Dimensional Blood Vessel Segmentation and Centerline Extraction based on Two-Dimensional Cross-Section Analysis.  

PubMed

The segmentation of tubular tree structures like vessel systems in volumetric datasets is of vital interest for many medical applications. In this paper we present a novel, semi-automatic method for blood vessel segmentation and centerline extraction, by tracking the blood vessel tree from a user-initiated seed point to the ends of the blood vessel tree. The novelty of our method is in performing only two-dimensional cross-section analysis for segmentation of the connected blood vessels. The cross-section analysis is done by our novel single-scale or multi-scale circle enhancement filter, used at the blood vessel trunk or bifurcation, respectively. The method was validated for both synthetic and medical images. Our validation has shown that the cross-sectional centerline error for our method is below 0.8 pixels and the Dice coefficient for our segmentation is 80%2.7%. On combining our method with an optional active contour post-processing, the Dice coefficient for the resulting segmentation is found to be 94%2.4%. Furthermore, by restricting the image analysis to the regions of interest and converting most of the three-dimensional calculations to two-dimensional calculations, the processing was found to be more than 18 times faster than Frangi vesselness with thinning, 8 times faster than user-initiated active contour segmentation with thinning and 7 times faster than our previous method. PMID:25398332

Kumar, Rahul Prasanna; Albregtsen, Fritz; Reimers, Martin; Edwin, Bjrn; Lang, Thomas; Elle, Ole Jakob

2014-11-15

231

Cytochrome c oxidase activity is deficient in blood vessels of patients with myoclonus epilepsy with ragged-red fibers  

Microsoft Academic Search

More than half of the intramuscular blood vessels in muscle biopsies from five patients with myoclonus epilepsy with ragged-fibers (MERRF) who had a point mutation in mitochondrial DNA at the tRNALys region were darkly stained with succinate dehydrogenase (SDH) stain, showing the morphologic characteristics of strongly SDH-reactive blood vessels (SSV), but they had no cytochrome c oxidase (CCO) activity. By

H. Hasegawa; T. Matsuoka; Y. Goto; I. Nonaka

1993-01-01

232

Multiple endothelial cells constitute the tip of developing blood vessels and polarize to promote lumen formation.  

PubMed

Blood vessel polarization in the apical-basal axis is important for directed secretion of proteins and lumen formation; yet, when and how polarization occurs in the context of angiogenic sprouting is not well understood. Here, we describe a novel topology for endothelial cells at the tip of angiogenic sprouts in several mammalian vascular beds. Two cells that extend filopodia and have significant overlap in space and time were present at vessel tips, both in vitro and in vivo. The cell overlap is more extensive than predicted for tip cell switching, and it sets up a longitudinal cell-cell border that is a site of apical polarization and lumen formation, presumably via a cord-hollowing mechanism. The extent of cell overlap at the tip is reduced in mice lacking aPKC?, and this is accompanied by reduced distal extension of both the apical border and patent lumens. Thus, at least two polarized cells occupy the distal tip of blood vessel sprouts, and topology, polarization and lumenization along the longitudinal border of these cells are influenced by aPKC?. PMID:25336741

Pelton, John C; Wright, Catherine E; Leitges, Michael; Bautch, Victoria L

2014-11-01

233

The murine allantois: a model system for the study of blood vessel formation  

PubMed Central

The allantois is the embryonic precursor of the umbilical cord in mammals and is one of several embryonic regions, including the yolk sac and dorsal aorta, that undergoes vasculogenesis, the de novo formation of blood vessels. Despite its importance in establishing the chorioallantoic placenta and umbilical circulation, the allantois frequently is overlooked in embryologic studies. Nonetheless, recent studies demonstrate that vasculogenesis, vascular remodeling, and angiogenesis are essential allantois functions in the establishment of the chorioallantoic placenta. Here, we review blood vessel formation in the murine allantois, highlighting the expression of genes and involvement of pathways common to vasculogenesis or angiogenesis in other parts of the embryo. We discuss experimental techniques available for manipulation of the allantois that are unavailable for yolk sac or dorsal aorta, and review how this system has been used as a model system to discover new genes and mechanisms involved in vessel formation. Finally, we discuss the potential of the allantois as a model system to provide insights into disease and therapeutics. PMID:22855605

Arora, Ripla

2012-01-01

234

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

PubMed Central

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

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

2009-01-01

235

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

236

Segmentation of Blood Vessels and 3D Representation of CMR Image  

NASA Astrophysics Data System (ADS)

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

Jiji, G. W.

2013-06-01

237

Localization of monoamine oxidase of type A and B in blood vessels with different innervation patterns.  

PubMed

Homogenates of dog mesenteric artery, dog saphenous vein, denervated saphenous vein, rabbit ear artery, denervated ear artery and human umbilical artery were prepared in phosphate buffer. Monoamine oxidase activity was determined with [3H]-5-hydroxytryptamine ([3H]-5-HT) as a preferential substrate for MAO type A and [14C]-beta-phenylethylamine as a preferential substrate for MAO type B. The endogenous noradrenaline content was compared with the MAO activities in these blood vessels. The results show that there is a good relationship of MAO type A content with the density of adrenergic innervation, but it is evident that this type of MAO is present even in vessels devoid of adrenergic innervation. Thus, MAO type A in these vascular structures has both intraneuronal and extraneuronal locations whereas MAO type B is predominantly or exclusively extraneuronal. PMID:6656891

Caramona, M M

1983-11-01

238

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

E-print Network

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.

Florian Janoschek; Federico Toschi; Jens Harting

2011-02-03

239

From Blood Islands to Blood Vessels: Morphologic Observations and Expression of Key Molecules during Hyaloid Vascular System Development  

PubMed Central

Purpose. The mode of development of the human hyaloid vascular system (HVS) remains unclear. Early studies suggested that these blood vessels formed by vasculogenesis, while the current concept seems to favor angiogenesis as the mode of development. We examined embryonic and fetal human HVS using a variety of techniques to gain new insights into formation of this vasculature. Methods. Embryonic and fetal human eyes from 5.5 to 12 weeks gestation (WG) were prepared for immunohistochemical analysis or for light and electron microscopy. Immunolabeling of sections with a panel of antibodies directed at growth factors, transcription factors, and hematopoietic stem cell markers was employed. Results. Light microscopic examination revealed free blood islands (BI) in the embryonic vitreous cavity (5.57 WG). Giemsa stain revealed that BI were aggregates of mesenchymal cells and primitive nucleated erythroblasts. Free cells were also observed. Immunolabeling demonstrated that BI were composed of mesenchymal cells that expressed hemangioblast markers (CD31, CD34, C-kit, CXCR4, Runx1, and VEGFR2), erythroblasts that expressed embryonic hemoglobin (Hb-?), and cells that expressed both. Few cells were proliferating as determined by lack of Ki67 antigen. As development progressed (12 WG), blood vessels became more mature structurally with pericyte investment and basement membrane formation. Concomitantly, Hb-? and CXCR4 expression was down-regulated and von Willebrand factor expression was increased with the formation of Weibel-Palade bodies. Conclusions. Our results support the view that the human HVS, like the choriocapillaris, develops by hemo-vasculogenesis, the process by which vasculogenesis, erythropoiesis, and hematopoiesis occur simultaneously from common precursors, hemangioblasts. PMID:23092923

McLeod, D. Scott; Hasegawa, Takuya; Baba, Takayuki; Grebe, Rhonda; Galtier d'Auriac, Ines; Merges, Carol; Edwards, Malia; Lutty, Gerard A.

2012-01-01

240

Mechanisms of ATP release and signalling in the blood vessel wall  

PubMed Central

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

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

2012-01-01

241

Adrenergic innervation of blood vessels in rat tibial nerve during Wallerian degeneration.  

PubMed

Adrenergic innervation of blood vessels in rat tibial nerve during Wallerian degeneration was examined, using the formaldehyde-induced histo-fluorescence method. The left sciatic nerve was transected at the level of the sciatic notch, whereas the right sciatic nerve was left intact and used as control. At 1, 3, 7, 14, 42, 56 or 84 days after transection, the tibial nerves of the transected and contralateral sides were exposed. Pieces of each nerve were used for light microscopy or for examination of adrenergic innervation with the fluorescence microscope. One day after transection, no adrenergic nerve fiber was observed in the endoneurium of the transected nerve. After 3 days, adrenergic innervation of small- and medium-sized arterioles in the epi-perineurium was absent, and after 7 days no fibers were visible around large arterioles. Fluorescent fibers were not detected even at 84 days post-surgery. It is concluded that adrenergic innervation of blood vessels in the rat tibial nerve is irreversibly lost after permanent axotomy, and that adrenergic regulation of nerve blood flow may also be lost. PMID:2275336

Koistinaho, J; Wadhwani, K C; Latker, C H; Balbo, A; Rapoport, S I

1990-01-01

242

Correlation mapping method of OCT for visualization blood vessels in brain  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

243

Tauroursodeoxycholic Acid, a Bile Acid, Promotes Blood Vessel Repair by Recruiting Vasculogenic Progenitor Cells.  

PubMed

Although serum bile acid concentrations are ~10 ?M in healthy subjects, the cross-talk 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 (FAP) via Akt activation. Interestingly, TUDCA induced integration of EPCs into human aortic endothelial cells (HAECs) by increasing adhesion molecule expression. In the mouse hindlimb 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 hindlimb 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 hindlimb 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. This article is protected by copyright. All rights reserved. PMID:25407160

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

2014-11-19

244

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

SciTech Connect

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; 330 ?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.

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

245

NCI Researchers Discover Genes That Are Turned On at High Levels in Tumor-Associated Blood Vessels of Mice and Humans  

Cancer.gov

A team of researchers at NCI has uncovered a set of genes that are turned on, or expressed, at high levels only in the blood vessels that feed tumors in mice and humans. These genes, and the proteins they encode, are important new potential targets for novel drugs that could selectively cut off a tumor's blood supply without affecting the blood vessels of healthy tissues, overcoming one of the major concerns of current anticancer therapies targeted at blood vessel growth.

246

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

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

247

Flowing microbubble manipulation in blood vessel phantom using ultrasonic standing wave with stepwise frequency  

NASA Astrophysics Data System (ADS)

An approach was demonstrated to gather, fix, and controllably shift flowing microbubbles in a blood vessel phantom. An ultrasonic standing wave field was generated by the superposition of the emission of a 5 MHz conventional transducer and the reflection from a bone surface. The acoustic radiation force gathered flowing microbubbles into the nodes, fixed some accumulated microbubble clusters in the flow condition, and shifted microbubbles to target site with stepwise frequency. The resolution of microbubble shift was approximately 4 ?m, and the low acoustic pressure range was from 4 to 16 kPa to avoid microbubble rupture.

Shi, Aiwei; Min, Yu; Wan, Mingxi

2013-10-01

248

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

SciTech Connect

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.

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

249

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

E-print Network

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

Cai, Xiao-Chuan

250

[Microsurgical blood vessel sutures using the so-called fibrin adhesive].  

PubMed

Since the development of microvascular surgery by Jacobson and Suarez, adaptation of vessel ends of less than 1 mm diameter has been performed by means of 8-10 interrupted sutures. Even the finest suture material, however, produces a foreign body reaction. In addition, necrosis of the media can be seen after insertion of interrupted sutures. After the initial demonstration in 1940 that divided nerves could be successfully rejoined by means of factors from the blood coagulation system, this technique was introduced to microsurgery in 1977. The present investigation was carried out on 50 end-to-end anastomoses in rat common carotid arteries. Subsequently, the healing process was studied by light and electron microscopy. The adhesive used was fibrinogen cryoprecipitate (Fibrinkleber-Human-Immuno), which polymerises after simultaneous application of thrombin. Electron microscopy shows no basic difference between the healing after this technique and the healing process after trauma to the vessel wall. This method, however, prevents regional necrosis of the vessel wall and reduces intimal thickening. The condition of the intimal lining appears better than in sutured anastomoses. The question, whether this change is due only to the absence of sutures or due also to application of fibrinogen, cannot be answered, however. PMID:6763588

Meyermann, R; Ahyai, A; Pini, C

1982-01-01

251

DSA Image Blood Vessel Skeleton Extraction Based on Anti-concentration Diffusion and Level Set Method  

NASA Astrophysics Data System (ADS)

Serious types of vascular diseases such as carotid stenosis, aneurysm and vascular malformation may lead to brain stroke, which are the third leading cause of death and the number one cause of disability. In the clinical practice of diagnosis and treatment of cerebral vascular diseases, how to do effective detection and description of the vascular structure of two-dimensional angiography sequence image that is blood vessel skeleton extraction has been a difficult study for a long time. This paper mainly discussed two-dimensional image of blood vessel skeleton extraction based on the level set method, first do the preprocessing to the DSA image, namely uses anti-concentration diffusion model for the effective enhancement and uses improved Otsu local threshold segmentation technology based on regional division for the image binarization, then vascular skeleton extraction based on GMM (Group marching method) with fast sweeping theory was actualized. Experiments show that our approach not only improved the time complexity, but also make a good extraction results.

Xu, Jing; Wu, Jian; Feng, Daming; Cui, Zhiming

252

A sandwich tubular scaffold derived from chitosan for blood vessel tissue engineering.  

PubMed

Many materials have been investigated in blood vessel tissue engineering, such as PGA, PLGA, P4HB. However, chitosan is not mentioned in the arena. This study aimed to develop a chitosan-based tubular scaffold and examine its feasibility of being applied in this field. Briefly, a knitted chitosan tube was dipped into chitosan solution (2%, w/v) and dried, then its inner and outer surface was mantled with a layer of chitosan/gelatin (4:1, w/w) complex solution, and then freeze-dehydrated. In vitro characterization showed that the scaffold had a wall of 1.0 mm in thickness with a sandwich structure, and a porosity of 81.2%. The pore diameter was 50-150 microm and could be regulated by varying freezing conditions. The scaffold possessed proper swelling property, burst strength of almost 4000 mmHg, and high suture-retention strength. After degradation for 2 months, the scaffold could maintain enough mechanical strength with an average mass loss of 18.7%. Vascular smooth muscle cells could spread and grow very well on the scaffold. This study provided a novel method to fabricate chitosan and its complex into a tubular scaffold and demonstrated the feasibility of the scaffold employed in the field of blood vessel tissue engineering. PMID:16400655

Zhang, Ling; Ao, Qiang; Wang, Aijun; Lu, Guangyuan; Kong, Lijun; Gong, Yandao; Zhao, Nanming; Zhang, Xiufang

2006-05-01

253

A chemically modified antibody mediates complete eradication of tumours by selective disruption of tumour blood vessels  

PubMed Central

Background: The possibility of eradicating cancer by selective destruction of tumour blood vessels may represent an attractive therapeutic avenue, but most pharmaceutical agents investigated so far did not achieve complete cures and are not completely specific. Antibody conjugates now allow us to evaluate the impact of selective vascular shutdown on tumour viability and to study mechanisms of action. Methods: We synthesised a novel porphyrin-based photosensitiser suitable for conjugation to antibodies and assessed anticancer properties of its conjugate with L19, a clinical-stage human monoclonal antibody specific to the alternatively spliced EDB domain of fibronectin, a marker of tumour angiogenesis. Results: Here we show in two mouse model of cancer (F9 and A431) that L19 is capable of highly selective in vivo localisation around tumour blood vessels and that its conjugate with a photosensitiser allows selective disruption of tumour vasculature upon irradiation, leading to complete and long-lasting cancer eradication. Furthermore, depletion experiments revealed that natural killer cells are essential for the induction of long-lasting complete responses. Conclusions: These results reinforce the concept that vascular shutdown can induce a curative avalanche of tumour cell death. Immuno-photodynamic therapy may be particularly indicated for squamous cell carcinoma of the skin, which we show to be strongly positive for markers of angiogenesis. PMID:21386847

Palumbo, A; Hauler, F; Dziunycz, P; Schwager, K; Soltermann, A; Pretto, F; Alonso, C; Hofbauer, G F; Boyle, R W; Neri, D

2011-01-01

254

The Effects of Impact Vibration on Peripheral Blood Vessels and Nerves  

PubMed Central

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

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

2013-01-01

255

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

PubMed Central

Ultrasound (US) sonication with microbubbles (MBs) has the potential to disrupt blood vessels and enhance the delivery of drugs into the sonicated tissues. In this study, mouse ear tumors were employed to investigate the therapeutic effects of US, MBs, and pegylated liposomal doxorubicin (PLD) on tumors. Tumors started to receive treatments when they grew up to about 15 mm3 (early stage) with injection of PLD 10 mg/kg, or up to 50 mm3 (medium stage) with PLD 6 (or 4) mg/kg. Experiments included the control, PLD alone, PLD + MBs + US, US alone, and MBs + US groups. The procedure for the PLD + MBs + US group was that PLD was injected first, MB (SonoVue) injection followed, and then US was immediately sonicated on the tumor. The results showed that: (1) US sonication with MBs was always able to produce a further hindrance to tumor growth for both early and medium-stage tumors; (2) for the medium-stage tumors, 6 mg/kg PLD alone was able to inhibit their growth, while it did not work for 4 mg/kg PLD alone; (3) with the application of MBs + US, 4 mg/kg PLD was able to inhibit the growth of medium-stage tumors; (4) for early stage tumors after the first treatment with a high dose of PLD alone (10 mg/kg), the tumor size still increased for several days and then decreased (a biphasic pattern); (5) MBs + US alone was able to hinder the growth of early stage tumors, but unable to hinder that of medium stage tumors. The results of histological examinations and blood perfusion measurements indicated that the application of MBs + US disrupts the tumor blood vessels and enhances the delivery of PLD into tumors to significantly inhibit tumor growth. PMID:22619550

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

2012-01-01

256

Automated Segmentation of 3-D Spectral OCT Retinal Blood Vessels by Neural Canal Opening False Positive Suppression  

Microsoft Academic Search

\\u000a We present a method for automatically segmenting the blood vessels in optic nerve head (ONH) centered spectral-domain optical\\u000a coherence tomography (SD-OCT) volumes, with a focus on the ability to segment the vessels in the region near the neural canal\\u000a opening (NCO). The algorithm first pre-segments the NCO using a graph-theoretic approach. Oriented Gabor wavelets rotated\\u000a around the center of the

Zhihong Hu; Meindert Niemeijer; Michael D. Abrmoff; Kyungmoo Lee; Mona Kathryn Garvin

2010-01-01

257

Segmentation and quantification of blood vessels for OCT-based micro-angiograms using hybrid shape/intensity compounding.  

PubMed

Optical coherence tomography (OCT) based microangiography is capable of visualizing 3D functional blood vessel networks within microcirculatory tissue beds in vivo. To provide the quantitative information of vasculature from the microangiograms such as vessel diameter and morphology, it is necessary to develop efficient vessel segmentation algorithms. In this paper, we propose to develop a hybrid Hessian/intensity based method to segment and quantify shape and diameter of the blood vessels innervating capillary beds that are imaged by functional OCT in vivo. The proposed method utilizes multi-scale Hessian filters to segment tubular structures such as blood vessels, but compounded by the intensity-based segmentation method to mitigate the limitations of Hessian filters' sensitivity to the selection of scale parameters. Such compounding segmentation scheme takes advantage of the morphological nature of Hessian filters while correcting for the scale parameter selection by intensity-based segmentation. The proposed algorithm is tested on a wound healing model and its performance of segmentation vessels is quantified by a publicly available manual segmentation dataset. We believe that this method will play an important role in the quantification of micro-angiograms for microcirculation research in ophthalmology and diagnosing retinal eye diseases involved with microcirculation. PMID:25283347

Yousefi, Siavash; Liu, Ting; Wang, Ruikang K

2015-01-01

258

Effect of impulse vibration and noise on vasomotor function of peripheral blood vessels among pneumatic forge hammer operators.  

PubMed

An evaluation of the effect of impulse vibration and noise on vasomotor function of blood vessels among pneumatic forge hammer operators has been presented based on thermal tests (cooling). The study covered the following groups of workers; pneumatic forge hammer operators (I), pneumatic forging hammer operators (II), hammer operator's assistants (III), operators of forging presses and machines (IV) and the control group. The results of the study showed that in groups I and III it was impulse noise not vibration that caused changes in the functioning of peripheral blood vessels. PMID:9150980

Solecki, L

1995-01-01

259

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

SciTech Connect

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

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

2007-08-01

260

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

PubMed Central

The vascular effects of arsenic in drinking water are global health concerns contributing to human disease worldwide. Arsenic targets the endothelial cells lining blood vessels and endothelial cell activation or dysfunction may underlie the pathogenesis of both arsenic-induced vascular diseases and arsenic-enhanced tumorigenesis. The purpose of the current studies was to demonstrate that exposing mice to drinking water containing environmentally relevant levels of arsenic promoted endothelial cell dysfunction and pathologic vascular remodeling. Increased angiogenesis, neovascularization, and inflammatory cell infiltration was observed in Matrigel plugs implanted in C57BL/6 mice following 5 week exposures to 5-500 ppb arsenic (Soucy et al., 2005). Therefore, functional in vivo effects of arsenic on endothelial cell function and vessel remodeling in an endogenous vascular bed were investigated in the liver. Liver sinusoidal endothelial cells (LSEC) became progressively defenestrated and underwent capillarization to decrease vessel porosity following exposure to 250 ppb arsenic for 2 weeks. Sinusoidal expression of PECAM-1 and laminin-1 proteins, a hallmark of capillarization, was also increased by 2 weeks of exposure. LSEC caveolin-1 protein and caveolae expression were induced after 2 weeks of exposure indicating a compensatory change. Likewise, CD45/CD68 positive inflammatory cells did not accumulate in the livers until after LSEC porosity was decreased; indicating that inflammation is a consequence and not a cause of the arsenic-induced LSEC phenotype. The data demonstrate that the liver vasculature is an early target of pathogenic arsenic effects and that the mouse liver vasculature is a sensitive model for investigating vascular health effects of arsenic. PMID:17123562

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

2006-01-01

261

Innervation of blood vessels in the vomeronasal complex of the rat.  

PubMed

We have made an immunohistochemical study of the vomeronasal (VN) complex of 12-day-old rats to characterize the innervation of its blood vessels. The VN complex can be subdivided into rostral, middle and caudal segments, each one with a particular vascularization pattern. Several small vessels were associated with the rostral segment, whereas a large venous sinus ran along the middle and caudal segments. Immunostaining for alpha-smooth muscle actin demonstrated that the muscular sheath was asymmetric, with more cells layers in its lateral than in its medial walls. Nerves were demonstrated with antisera against protein gene product 9.5 (PGP), and against several molecules associated with specific classes of nerve fibers: the C-terminal peptide of neuropeptide Y (CPON), calcitonin gene-related peptide (CGRP), substance P (SP), galanin (GAL), vasoactive intestinal peptide (VIP) and neuronal nitric oxide synthase (NOS). The latter, was also studied with NADPH-diaphorase. Vascular associated fibers exhibited NOS-, CPON-, GAL-, CGRP-, SP- and VIP-immunoreactivity. Only the vessels of the rostral segment showed VIP-immunoreactive fibers. Each wall of the venous sinus exhibited different types of nerve fibers. CPON-, GAL-, CGRP- and SP-immunoreactive fibers concentrated in the medial wall, whereas NOS-immunoreactive ones concentrated in the lateral wall. This distribution of vascular fibers, plus the presence of sensory fibers exhibiting CGRP-, SP- and GAL-immunoreactivity within the pseudostratified epithelium of the VN tube, would be relevant to understand the operation of the pumping mechanism regulating influx and efflux from the VN tube. PMID:9804888

Cant Soler, M V; Suburo, A M

1998-11-16

262

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

PubMed Central

In magnetic drug delivery, therapeutic magnetizable particles are typically injected into the blood stream and magnets are then used to concentrate them to disease locations. The behavior of such particles in-vivo is complex and is governed by blood convection, diffusion (in blood and in tissue), extravasation, and the applied magnetic fields. Using physical first-principles and a sophisticated vessel-membrane-tissue (VMT) numerical solver, we comprehensively analyze in detail the behavior of magnetic particles in blood vessels and surrounding tissue. For any blood vessel (of any size, depth, and blood velocity) and tissue properties, particle size and applied magnetic fields, we consider a Krogh tissue cylinder geometry and solve for the resulting spatial distribution of particles. We find that there are three prototypical behaviors (blood velocity dominated, magnetic force dominated, and boundary-layer formation) and that the type of behavior observed is uniquely determined by three non-dimensional numbers (the magnetic-Richardson number, mass Pclet number, and Renkin reduced diffusion coefficient). Plots and equations are provided to easily read out which behavior is found under which circumstances (Figures 5, 6, 7, and 8). We compare our results to previously published in-vitro and in-vivo magnetic drug delivery experiments. Not only do we find excellent agreement between our predictions and prior experimental observations, but we are also able to qualitatively and quantitatively explain behavior that was previously not understood. PMID:21278859

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

2010-01-01

263

Heparin functionalized polyaspartamide/polyester scaffold for potential blood vessel regeneration.  

PubMed

An interesting issue in tissue engineering is the development of a biodegradable vascular graft able to substitute a blood vessel and to allow its complete regeneration. Here, we report a new scaffold potentially useful as a synthetic vascular graft, produced through the electrospinning of ?,?-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide-graft-polylactic acid (PHEA-EDA-g-PLA) in the presence of polycaprolactone (PCL). The scaffold degradation profile has been evaluated as well as the possibility to bind heparin to electrospun fibers, being it a known anticoagulant molecule able to bind growth factors. In vitro cell compatibility has been investigated using human vascular endothelial cells (ECV 304) and the ability of heparinized PHEA-EDA-g-PLA/PCL scaffold to retain basic fibroblast growth factor has been evaluated in comparison with not heparinized sample. PMID:23733561

Pitarresi, Giovanna; Fiorica, Calogero; Palumbo, Fabio Salvatore; Rigogliuso, Salvatrice; Ghersi, Giulio; Giammona, Gaetano

2014-05-01

264

Angiogenin Expression during Early Human Placental Development; Association with Blood Vessel Formation  

PubMed Central

The placenta is a transient organ essential for fetal development. During human placental development, chorionic villi grow in coordination with a large capillary network resulting from both vasculogenesis and angiogenesis. Angiogenin is one of the most potent inducers of neovascularisation in experimental models in vivo. We and others have previously mapped angiogenin expression in the human term placenta. Here, we explored angiogenin involvement in early human placental development. We studied, angiogenin expression by in situ hybridisation and/or by RT-PCR in tissues and primary cultured trophoblastic cells and angiogenin cellular distribution by coimmunolabelling with cell markers: CD31 (PECAM-1), vascular endothelial cadherin (VE-cadherin), vascular endothelial growth factor receptor-2 (VEGF-R2), Tie-2, von Willebrand factor, CD34, erythropoeitin receptor (Epo-R), alpha-smooth muscle actin, CD45, cytokeratin 7, and Ki-67. Extravillous and villous cytotrophoblasts, isolated and differentiated in vitro, expressed and secreted angiogenin. Angiogenin was detected in villous trophoblastic layers, and structured and nascent fetal vessels. In decidua, it was expressed by glandular epithelial cells, vascular cells and macrophages. The observed pattern of angiogenin expression is compatible with a role in blood vessel formation and in cross-talk between trophoblasts and endothelial cells. In view of angiogenin properties, we suggest that angiogenin may participate in placental vasculogenesis and organogenesis. PMID:25093183

Pavlov, Nadine; Guibourdenche, Jean; Degrelle, Sverine A.; Evain-Brion, Danile

2014-01-01

265

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

266

Quantification of the endothelial surface glycocalyx on rat and mouse blood vessels  

PubMed Central

The glycocalyx on the surface of endothelium lining blood vessel walls modulates vascular barrier function, cell adhesion and also serves as a mechano-sensor for blood flow. Reduction of glycocalyx has been reported in many diseases including atherosclerosis, inflammation, myocardial edema, and diabetes. The surface glycocalyx layer (SGL) is composed of proteoglycans and glycosaminoglycans, of which heparan sulfate is one of the most abundant. To quantify the SGL thickness on the microvessels of rat mesentery and mouse cremaster muscle in situ, we applied a single vessel cannulation and perfusion technique to directly inject FITC-anti-heparan sulfate into a group of microvessels for immuno-labeling the SGL. We also used anti-heparan sulfate for immuno-labeling the SGL on rat and mouse aortas ex vivo. High resolution confocal microscopy revealed that the thickness of the SGL on rat mesenteric capillaries and post-capillary venules is 0.9 0.1 ?m and 1.2 0.3 ?m, respectively; while the thickness of the SGL on mouse cremaster muscle capillaries and post-capillary venules is 1.5 0.1 ?m and 1.5 0.2 ?m, respectively. Surprisingly, there was no detectable SGL in either rat mesenteric or mouse cremaster muscle arterioles. The SGL thickness is 2.5 0.1 ?m and 2.1 0.2 ?m respectively, on rat and mouse aorta. In addition, we observed that the SGL is continuously and evenly distributed on the aorta wall but not on the microvessel wall. PMID:22349291

Yen, Wan-Yi; Cai, Bin; Zeng, Min; Tarbell, John M.; Fu, Bingmei M.

2012-01-01

267

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

Microsoft Academic Search

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

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

1994-01-01

268

Effect of 5-HT(2A) receptor antagonists on blood flow in the carotid vessels upon elevation of serotonin level.  

PubMed

We studied the ability of predominantly 5-HT2A receptor antagonists to prevent a serotonin-induced change of blood flow in the carotid vessels of rats with experimental serotonin-induced spasm. Ritanserin, ketanserin, and 5-HT2A receptor antagonist RU-476 reduced the effect of serotonin on the blood fl ow velocity in the internal carotid artery by 2.3, 1.7, and 2.6 times, respectively. PMID:25070162

Yakovlev, D S; Spasov, A A; Mal'tsev, D V; Anisimova, V A

2014-07-01

269

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

PubMed Central

As part of the inflammation response, white blood cells (leukocytes) are well known to bind nearly statically to the vessel walls, where they must resist the force exerted by the flowing blood. This force is particularly difficult to estimate due to the particulate character of blood, especially in small vessels where the red blood cells must substantially deform to pass an adhered leukocyte. An efficient simulation tool with realistically flexible red blood cells is used to estimate these forces. At these length scales, it is found that the red cells significantly augment the streamwise forces that must be resisted by the binding. However, interactions with the red cells are also found to cause an average wall-directed force, which can be anticipated to enhance binding. These forces increase significantly as hematocrit values approach 25% and decrease significantly as the leukocyte is made flatter on the wall. For a tube hematocrit of 25% and a spherical protrusion with a diameter three-quarters that of the vessel, the average forces are increased by ?40% and the local forces are more than double those estimated with an effective-viscosity-homogenized blood. Both the enhanced streamwise and wall-ward forces and their unsteady character are potentially important in regard to binding mechanisms. PMID:23062353

Isfahani, AmirH.G.; Freund, JonathanB.

2012-01-01

270

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

PubMed

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

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

2014-08-01

271

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

PubMed Central

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 plateletplatelet 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 receptorligand 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

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

2014-01-01

272

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

PubMed

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

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

273

Human Blood VesselDerived Endothelial Progenitors for Endothelialization of Small Diameter Vascular Prosthesis  

PubMed Central

Background Coronary bypass graft failure as a result of acute thrombosis and intimal hyperplasia has been the major challenge in surgical procedures involving small-diameter vascular prosthesis. Coating synthetic grafts with patients' own endothelial cells has been suggested to improve the patency rate and overall success of bypass surgeries. Methodology/Principal Findings We isolated endothelial progenitor cells (EPCs) from leftover pieces of human saphenous vein/mammary artery. We demonstrate that EPCs can be expanded to generate millions of cells under low-density culture conditions. Exposure to high-density conditions induces differentiation to endothelial cell phenotype. EPCderived endothelial cells show expression of CD144high, CD31, and vWF. We then assessed the ability of differentiated endothelial cells to adhere and grow on small diameter expanded polytetrafluoroethylene (ePTFE) tubings. Since ePTFE tubings are highly hydrophobic, we optimized protocols to introduce hydrophilic groups on luminal surface of ePTFE tubings. We demonstrate here a stepwise protocol that involves introduction of hydrophilic moieties and coating with defined ECM components that support adhesion of endothelial cells, but not of blood platelets. Conclusion/Significance Our data confirms that endothelial progenitors obtained from adult human blood vessels can be expanded in vitro under xenoprotein-free conditions, for potential use in endothelialization of small diameter ePTFE grafts. These endothelialized grafts may represent a promising treatment strategy for improving the clinical outcome of small-caliber vascular grafts in cardiac bypass surgeries. PMID:19890388

Ranjan, Amaresh K.; Kumar, Umesh; Hardikar, Ashutosh A.; Poddar, Pankaj; Nair, Prabha D.; Hardikar, Anandwardhan A.

2009-01-01

274

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

PubMed Central

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

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

275

Characterization of Imidazoline Receptors in Blood Vessels for the Development of Antihypertensive Agents  

PubMed Central

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

Chen, Mei-Fen; 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

276

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

PubMed

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

Greaves, Alana K; Letcher, Robert J

2013-09-01

277

Negative contrast Cerenkov luminescence imaging of blood vessels in a tumor mouse model using [68Ga]gallium chloride  

PubMed Central

Background Cerenkov luminescence imaging (CLI) is an emerging imaging technique where visible light emitted from injected beta-emitting radionuclides is detected with an optical imaging device. CLI research has mostly been focused on positive contrast imaging for ascertaining the distribution of the radiotracer in a way similar to other nuclear medicine techniques. Rather than using the conventional technique of measuring radiotracer distribution, we present a new approach of negative contrast imaging, where blood vessel attenuation of Cerenkov light emitted by [68Ga]GaCl3 is used to image vasculature. Methods BALB/c nude mice were injected subcutaneously in the right flank with HT-1080 fibrosarcoma cells 14 to 21days prior to imaging. On the imaging day, [68Ga]GaCl3 was injected and the mice were imaged from 45 to 90min after injection using an IVIS Spectrum in vivo imaging system. The mice were imaged one at a time, and manual focus was used to bring the skin into focus. The smallest view with pixel size around 83?m was used to achieve a sufficiently high image resolution for blood vessel imaging. Results The blood vessels in the tumor were clearly visible, attenuating 7% to 18% of the light. Non-tumor side blood vessels had significantly reduced attenuation of 2% to 4%. The difference between the attenuation of light of tumor vessels (10%??4%) and the non-tumor vessels (3%??1%) was significant. Moreover, a necrotic core confirmed by histology was clearly visible in one of the tumors with a 21% reduction in radiance. Conclusions The negative contrast CLI technique is capable of imaging vasculature using [68Ga]GaCl3. Since blood vessels smaller than 50?m in diameter could be imaged, CLI is able to image structures that conventional nuclear medicine techniques cannot. Thus, the negative contrast imaging technique shows the feasibility of using CLI to perform angiography on superficial blood vessels, demonstrating an advantage over conventional nuclear medicine techniques. PMID:24606872

2014-01-01

278

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

PubMed

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

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

2014-10-23

279

High Tissue Glucose Alters Intersomitic Blood Vessels in Zebrafish via Methylglyoxal Targeting the VEGF Receptor Signaling Cascade.  

PubMed

Hyperglycemia causes micro- and macrovascular complications in diabetic patients. Elevated glucose concentrations lead to increased formation of the highly reactive dicarbonyl methylglyoxal (MG), yet the early consequences of MG for development of vascular complications in vivo are poorly understood. In this study, zebrafish were used as a model organism to analyze early vascular effects and mechanisms of MG in vivo. High tissue glucose increased MG concentrations in tg(fli:EGFP) zebrafish embryos and rapidly induced several additional malformed and uncoordinated blood vessel structures that originated out of existing intersomitic blood vessels (ISVs). However, larger blood vessels, including the dorsal aorta and common cardinal vein, were not affected. Expression silencing of MG-degrading enzyme glyoxalase (glo) 1 elevated MG concentrations and induced a similar vascular hyperbranching phenotype in zebrafish. MG enhanced phosphorylation of vascular endothelial growth factor (VEGF) receptor 2 and its downstream target Akt/protein kinase B (PKB). Pharmacological inhibitors for VEGF receptor 2 and Akt/PKB as well as MG scavenger aminoguanidine and glo1 activation prevented MG-induced hyperbranching of ISVs. Taken together, MG acts on smaller blood vessels in zebrafish via the VEGF receptor signaling cascade, thereby describing a new mechanism that can explain vascular complications under hyperglycemia and elevated MG concentrations. PMID:25092676

Jrgens, Kristina; Stoll, Sandra J; Pohl, Jennifer; Fleming, Thomas H; Sticht, Carsten; Nawroth, Peter P; Hammes, Hans-Peter; Kroll, Jens

2015-01-01

280

Predicting effects of blood flow rate and size of vessels in a vasculature on hyperthermia treatments using computer simulation  

Microsoft Academic Search

BACKGROUND: Pennes Bio Heat Transfer Equation (PBHTE) has been widely used to approximate the overall temperature distribution in tissue using a perfusion parameter term in the equation during hyperthermia treatment. In the similar modeling, effective thermal conductivity (Keff) model uses thermal conductivity as a parameter to predict temperatures. However the equations do not describe the thermal contribution of blood vessels.

Huang-Wen Huang; Tzu-Ching Shih; Chihng-Tsung Liauh

2010-01-01

281

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

Microsoft Academic Search

Primary vasculogenesis in chick embryos at the early somite stage 1114 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

Reiji Hirakow; Tamiko Hiruma

1981-01-01

282

Simulation of Surface EMG Signals for a Multilayer Volume Conductor With a Superficial Bone or Blood Vessel  

Microsoft Academic Search

This study analytically describes surface electromyogram (EMG) signals generated by a planar multilayer volume conductor constituted by different subdomains modeling muscle, bone (or blood vessel), fat, and skin tissues. The bone is cylindrical in shape, with a semicircular section. The flat portion of the boundary of the bone subdomain is interfaced with the fat layer tissue, the remaining part of

Luca Mesin

2008-01-01

283

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

PubMed Central

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

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

2012-01-01

284

Molecular Dynamics Simulation of Soft Grains: Malaria-Infected Red Blood Cells Motion within Obstructed 2-D Capillary Vessel  

E-print Network

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. Keywords: molecular dynamics, two-dimensional model, red-blood cell motion, malaria

Haris, Luman; Haryanto, Freddy; Viridi, Sparisoma

2013-01-01

285

Numerical modeling of the pulse wave propagation in large blood vessels based on liquid and wall interaction  

NASA Astrophysics Data System (ADS)

The purpose of this article is to develop a non-linear, one-dimensional model of pulse wave propagation in the arterial cardiovascular system. The model includes partial differential equations resulting from the balance of mass and momentum for the fluid-filled area and the balance equation for the area of the wall and vessels. The considered mathematical model of pulse wave propagation in the thoracic aorta section takes into account the viscous dissipation of fluid energy, realistic values of parameters describing the physicochemical properties of blood and vessel wall. Boundary and initial conditions contain the appropriate information obtained from in vivo measurements. As a result of the numerical solution of the mass and momentum balance equations for the blood and the equilibrium equation for the arterial wall area, time- dependent deformation, respective velocity profiles and blood pressure were determined.

Rup, K.; Dr?d?, A.

2014-08-01

286

Analysis of the fast scanning method for tumor ablation with the effect of the large blood vessel by numerical simulation  

NASA Astrophysics Data System (ADS)

While using HIFU for tumor ablation, the focal size of the ultrasound is relatively small compared with the tumor, therefore, numerous sonications are necessary to cover the whole treatment area. A large number of foci, on the other hand, lead to a complex problem for the optimization of the treatment parameters. Moreover, the existence of the large vessel might reduce the size of the lesion volume. A fast scanning method for volumetric ablation is investigated by numerical simulation with the effect of the large blood vessel. The proposed method is only available for phased array transducers because fast switch at the frequency of 10 Hz between several predetermined focus positions is needed. Since the duration time for each single ablation was identical, ignoring the ultrasound power, the scan path is the major parameter that should be decided. Five scan paths are simulated with and without a large vessel (diameter of 6mm) in the compute domain. The simulations solved by finite element method showed that the size of formed lesions had little difference while different scan paths applied. While the proposed scan method was used, the impact of the blood flow on the lesion volume depended on the distance between the large vessel and the focal area, as same as previous researches in the single focus case. Additionally, the orientation of the vessel played an important role in the formation of lesions.

Qiao, Shan; Shen, Guofeng; Bai, Jingfeng; Chen, Yazhu

2012-11-01

287

Software-assisted live visualization system for subjacent blood vessels in endonasal endoscopic approaches  

NASA Astrophysics Data System (ADS)

Minimal invasive surgery methods have received growing attention in recent years. In vital important areas, it is crucial for the surgeon to have a precise knowledge of the tissue structure. Especially the visualization of arteries is desirable, as the destruction of the same can be lethal to the patient. In order to meet this requirement, the study presents a novel assistance system for endoscopic surgery. While state-of-the art systems rely on pre-operational data like computer-tomographic maps and require the use of radiation, the goal of the presented approach is to provide the clarification of subjacent blood vessels on live images of the endoscope camera system. Based on the transmission and reflection spectra of various human tissues, a prototype system with a NIR illumination unit working at 808 nm was established. Several image filtering, processing and enhancement techniques have been investigated and evaluated on the raw pictures in order to obtain high quality results. The most important were increasing contrast and thresholding by difference of Gaussian method. Based on that, it is possible to rectify a fragmented artery pattern and extract geometrical information about the structure in terms of position and orientation. By superposing the original image and the extracted segment, the surgeon is assisted with valuable live pictures of the region of interest. The whole system has been tested on a laboratory scale. An outlook on the integration of such a system in a clinical environment and obvious benefits are discussed.

Lempe, B.; Taudt, Ch.; Maschke, R.; Gruening, J.; Ernstberger, M.; Basan, F.; Baselt, T.; Grunert, R.; Hartmann, P.

2013-02-01

288

[A case of giant presacral neurilemoma resected without blood transfusion after embolization of tumor vessels].  

PubMed

A 71-year-old man began feeling a lower abdominal pain at bowel movement about one year ago. He was found to have a pelvic tumor during a health examination and referred to our hospital for further evaluation. CT and MRI scans demonstrated a giant pelvic tumor, 10 cm in size, which compressed the rectum. The likely preoperative diagnosis was leiomyosarcoma from the rectum or neurilemoma. To regulate intraoperative hemorrhaging and to reduce the tumor size, angiography was performed at two days before the operation and embolization of the tumor vessels was done. He had a tumor resection and a low anterior resection of the rectum and a transient colostomy of the ascending colon without blood transfusion. The resected tumor was covered with thin yellowish-white capsule with smooth surface, elastic hard on palpation, and was measured 10.5 9 10.5 cm, and weighted 320 g. The pathological diagnosis was neurilemoma (schwannoma) consisting both Antoni type A and Antoni type B sections. PMID:21224559

Hosaka, Seiji; Yamamoto, Nobuharu; Kawamoto, Shunji; Yamashita, Kanefumi; Ochiai, Ryouji; Okubo, Shouichi; Nagao, Shuji; Inada, Kazuo; Yoshida, Takahisa

2010-11-01

289

Regulation of signaling interactions and receptor endocytosis in growing blood vessels.  

PubMed

Blood vessels and the lymphatic vasculature are extensive tubular networks formed by endothelial cells that have several indispensable functions in the developing and adult organism. During growth and tissue regeneration but also in many pathological settings, these vascular networks expand, which is critically controlled by the receptor EphB4 and the ligand ephrin-B2. An increasing body of evidence links Eph/ephrin molecules to the function of other receptor tyrosine kinases and cell surface receptors. In the endothelium, ephrin-B2 is required for clathrin-dependent internalization and full signaling activity of VEGFR2, the main receptor for vascular endothelial growth factor. In vascular smooth muscle cells, ephrin-B2 antagonizes clathrin-dependent endocytosis of PDGFR? and controls the balanced activation of different signal transduction processes after stimulation with platelet-derived growth factor. This review summarizes the important roles of Eph/ephrin molecules in vascular morphogenesis and explains the function of ephrin-B2 as a molecular hub for receptor endocytosis in the vasculature. PMID:25482636

Pitulescu, Mara E; Adams, Ralf H

2014-07-01

290

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

PubMed Central

Cardiovascular disease (CVD) is more common in postmenopausal than premenopausal women, suggesting vascular protective effects of estrogen. Vascular estrogen receptors ER?, ER? and a transmembrane estrogen-binding protein GPR30 have been described. Also, experimental studies have demonstrated vasodilator effects of estrogen on the endothelium, vascular smooth muscle and extracellular matrix. However, randomized clinical trials have not supported vascular benefits of menopausal hormone therapy (MHT), possibly due to the subjects' advanced age and age-related changes in estrogen synthesis and metabolic pathways, the vascular ERs number, distribution and integrity, and the post-ER vascular signaling pathways. Current MHT includes natural estrogens such as conjugated equine estrogen, as well as synthetic and semi-synthetic estrogens. New estrogenic formulations and hormone combinations have been developed. Phytoestrogens is being promoted as an alternative MHT. Specific ER modulators (SERMs), and selective agonists for ER? such as PPT, ER? such as DPN, and GPR30 such as G1 are being evaluated. In order to enhance the vascular effectiveness of MHT, its type, dose, route of administration and timing may need to be customized depending on the subject's age and pre-existing CVD. Also, the potential interaction of estrogen with progesterone and testosterone on vascular function may need to be considered in order to maximize the vascular benefits of MHT on senescent blood vessels and postmenopausal CVD. PMID:20210774

Khalil, Raouf A.

2010-01-01

291

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

PubMed

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

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

2014-12-01

292

Noncoding RNAs regulate NF-?B signaling to modulate blood vessel inflammation  

PubMed Central

Cardiovascular diseases such as atherosclerosis are one of the leading causes of morbidity and mortality worldwide. The clinical manifestations of atherosclerosis, which include heart attack and stroke, occur several decades after initiation of the disease and become more severe with age. Inflammation of blood vessels plays a prominent role in atherogenesis. Activation of the endothelium by inflammatory mediators leads to the recruitment of circulating inflammatory cells, which drives atherosclerotic plaque formation and progression. Inflammatory signaling within the endothelium is driven predominantly by the pro-inflammatory transcription factor, NF-?B. Interestingly, activation of NF-?B is enhanced during the normal aging process and this may contribute to the development of cardiovascular disease. Importantly, studies utilizing mouse models of vascular inflammation and atherosclerosis are uncovering a network of noncoding RNAs, particularly microRNAs, which impinge on the NF-?B signaling pathway. Here we summarize the literature regarding the control of vascular inflammation by microRNAs, and provide insight into how these microRNA-based pathways might be harnessed for therapeutic treatment of disease. We also discuss emerging areas of endothelial cell biology, including the involvement of long noncoding RNAs and circulating microRNAs in the control of vascular inflammation.

Cheng, Henry S.; Njock, Makon-Sbastien; Khyzha, Nadiya; Dang, Lan T.; Fish, Jason E.

2014-01-01

293

QUANTITATIVE ALTERATIONS IN THE HYPEREMIA RESPONSES TO LOCAL ISCHEMIA OF THE SMALLEST BLOOD VESSELS OF THE HUMAN SKIN FOLLOWING SYSTEMIC ANOXEMIA, HYPERCAPNIA, ACIDOSIS, AND ALKALOSIS  

Microsoft Academic Search

Little is known of the nature of the relationship of the concentration of blood gases, and of changes in pH of the blood to the responsiveness or state of tonns of the finest blood vessels (i.e., the vessels beyond the arterioles). Investiga- tions of a qualitative nature have led to the gene.ral belief that acids and carbon dioxide cause dilatation

JOSEPH R. DIPALMA

294

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

SciTech Connect

An implanted system is being developed to monitor transplanted liver health during the critical 7-10 day period posttransplantation. The unit will monitor organ perfusion and oxygen consumption using optically-based probes placed on both the inflow and outflow blood vessels, and on the liver parenchymal surface. Sensing probes are based on a 3- wavelength LED source and a photodiode detector. Sample diffuse reflectance is measured at 735, 805, and 940 nm. To ascertain optimal source-to-photodetector spacing for perfusion measurement in blood vessels, an ex vivo study was conducted. In this work, a dye mixture simulating 80% blood oxygen saturation was developed and perfused through excised porcine arteries while collecting data for various preset probe source-to-photodetector spacings. The results from this study demonstrate a decrease in the optical signal with decreasing LED drive current and a reduction in perfusion index signal with increasing probe spacing. They also reveal a 2- to 4-mm optimal range for blood vessel perfusion probe source-to-photodetector spacing that allows for sufficient perfusion signal modulation depth with maximized signal to noise ratio (SNR). These findings are currently being applied to guide electronic configuration and probe placement for in vivo liver perfusion porcine model studies.

Baba, Justin S [ORNL; Akl, Tony [Texas A& M University; Cote, Gerard L. [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL

2011-01-01

295

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)

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.

Doblhoff-Dier, Veronika; Werkmeister, Ren M.; Grschl, Martin; Schmetterer, Leopold

2014-03-01

296

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

297

Studies on pregnancy hypertension and IUGR-SFD: effects of drugs on the blood vessels in the placenta of pregnant SHRSP.  

PubMed

1. Based upon our previous work, we came to the conclusion that a decrease in placental blood volume was a possible factor behind intrauterine growth retardation (IUGR) in pregnancy-induced hypertension. 2. In a second study, we used an image analysis system to measure cross-sectional areas and wall thicknesses of central blood vessels of the spiral artery, the so-called 'central artery'. 3. It was thought that one of the more basic factors behind IUGR in pregnancy-induced hypertension might possibly be narrowings and spasms of the maternal placental blood vessels. 4. In this study, we found that the three drugs we used (MgSO4 center dot 7H2O, Solcoseryl and KCl) all resulted in an enlargement of the cross-sectional areas of the maternal blood vessels, and that MgSO4 center dot 7H2O, in particular, also relaxed maternal blood vessel spasms in SHRSP placenta. PMID:9072394

Fuchi, I; Noda, K; Matsubara, Y

1995-12-01

298

Reduced laminin immunoreactivity in the blood vessel wall of ageing rats correlates with reduced innervation in vivo and following transplantation  

Microsoft Academic Search

Changes in extracellular matrix composition and\\/or organisation, and in particular in the ratio of axonal growth-promoting components such as laminin to growth-inhibiting molecules, could contribute to the degenerative changes observed in the innervation of some peripheral tissues in old age. We have investigated this issue by evaluating laminin content or accessibility at various locations on blood vessels where we had

Isabella Gavazzi; Karen S. Boyle; David Edgar; Timothy Cowen

1995-01-01

299

Blood Vessels Segmentation in Retina: Preliminary Assessment of the Mathematical Morphology and of the Wavelet Transform Techniques  

Microsoft Academic Search

http:\\/\\/www.ime.usp.br\\/~cesar\\/ Abstract. This work reports the development of a system for automatic analysis of retinal angiographic images. Particularly, we focus on the segmentation o f the blood vessels in these images. We started by implementing a previously k nown technique based on mathematical morphology. Due to some short comings of this method to ou r data, we have developed a

Jorge J. G. Leandro; Roberto Marcondes Cesar Junior; Herbert F. Jelinek

2001-01-01

300

BLOOD VESSELS IN GANGLIA IN HUMAN ESOPHAGUS MIGHT EXPLAIN THE HIGHER FREQUENCY OF MEGAESOPHAGUS COMPARED WITH MEGACOLON  

PubMed Central

This study aimed to determine the existence of blood vessels within ganglia of the myenteric plexus of the human esophagus and colon. At necropsy, 15 stillborns, newborns and children up to two years of age, with no gastrointestinal disorders, were examined. Rings of the esophagus and colon were analyzed and then fixed in formalin and processed for paraffin. Histological sections were stained by hematoxylin-eosin, Giemsa and immunohistochemistry for the characterization of endothelial cells, using antibodies for anti-factor VIII and CD31. Blood vessels were identified within the ganglia of the myenteric plexus of the esophagus, and no blood vessels were found in any ganglia of the colon. It was concluded that the ganglia of the myenteric plexus of the esophagus are vascularized, while the ganglia of the colon are avascular. Vascularization within the esophageal ganglia could facilitate the entrance of infectious agents, as well as the development of inflammatory responses (ganglionitis) and denervation, as found in Chagas disease and idiopathic achalasia. This could explain the higher frequency of megaesophagus compared with megacolon. PMID:25351549

Adad, Sheila Jorge; Etchebehere, Renata Margarida; Jammal, Alessandro Adad

2014-01-01

301

Assessing advantages of sequential boron neutron capture therapy (BNCT) in an oral cancer model with normalized blood vessels.  

PubMed

Abstract Background. We previously demonstrated the therapeutic success of sequential boron neutron capture therapy (Seq-BNCT) in the hamster cheek pouch oral cancer model. It consists of BPA-BNCT followed by GB-10-BNCT 24 or 48 hours later. Additionally, we proved that tumor blood vessel normalization with thalidomide prior to BPA-BNCT improves tumor control. The aim of the present study was to evaluate the therapeutic efficacy and explore potential boron microdistribution changes in Seq-BNCT preceded by tumor blood vessel normalization. Material and Methods. Tumor bearing animals were treated with thalidomide for tumor blood vessel normalization, followed by Seq-BNCT (Th+ Seq-BNCT) or Seq-Beam Only (Th+ Seq-BO) in the window of normalization. Boron microdistribution was assessed by neutron autoradiography. Results. Th+ Seq-BNCT induced overall tumor response of 100%, with 87 (4)% complete tumor response. No cases of severe mucositis in dose-limiting precancerous tissue were observed. Differences in boron homogeneity between tumors pre-treated and not pre-treated with thalidomide were observed. Conclusion. Th+ Seq-BNCT achieved, for the first time, response in all treated tumors. Increased homogeneity in tumor boron microdistribution is associated to an improvement in tumor control. PMID:24960584

Molinari, Ana J; Thorp, Silvia I; Portu, Agustina M; Saint Martin, Gisela; Pozzi, Emiliano C C; Heber, Elisa M; Bortolussi, Silva; Itoiz, Maria E; Aromando, Romina F; Monti Hughes, Andrea; Garabalino, Marcela A; Altieri, Saverio; Trivillin, Vernica A; Schwint, Amanda E

2015-01-01

302

Estrogenic Compounds, Estrogen Receptors and Vascular Cell Signaling in the Aging Blood Vessels  

PubMed Central

The cardiovascular benefits of menopausal hormone therapy (MHT) remain controversial. The earlier clinical observations that cardiovascular disease (CVD) was less common in MHT users compared to non-users suggested cardiovascular benefits of MHT. Also, experimental studies have identified estrogen receptors ER?, ER? and GPR30, which mediate genomic or non-genomic effects in vascular endothelium, smooth muscle, and extracellular matrix (ECM). However, data from randomized clinical trials (RCTs), most notably the Women's Health Initiative (WHI) study, have challenged the cardiovascular benefits and highlighted adverse cardiovascular events with MHT. The discrepancies have been attributed to the design of RCTs, the subjects' advanced age and preexisting CVD, and the form of estrogen used. The discrepancies may also stem from age-related changes in vascular ER amount, distribution, integrity, and post-receptor signaling pathways as well as structural changes in the vasculature. Age-related changes in other sex hormones such as testosterone may also alter the hormonal environment and influence the cardiovascular effects of estrogen. Investigating the chemical properties, structure-activity relationship and pharmacology of natural and synthetic estrogens should improve the effectiveness of conventional MHT. Further characterization of phytoestrogens, selective estrogen-receptor modulators (SERMs), and specific ER agonists may provide substitutes to conventional MHT. Conditions with excess or low estrogen levels such as polycystic ovary syndrome (PCOS) and Turner syndrome may provide insight into the development and regulation of ER and the mechanisms of aberrant estrogen-ER interactions. The lessons learned from previous RCTs have led to more directed studies such as the Kronos Early Estrogen Prevention Study (KEEPS). Careful design of experimental models and RCTs, coupled with the development of specific ER modulators, hold the promise of improving the actions of estrogen in the aging blood vessels and thereby enhancing the efficacy and safety of MHT in postmenopausal CVD. PMID:19442151

Smiley, Dia A.; Khalil, Raouf A.

2010-01-01

303

The role of the carotid body chemoreceptors and carotid sinus baroreceptors in the control of cerebral blood vessels  

PubMed Central

1. Cerebral blood flow was measured in 17 baboons, anaesthetized with pentobarbitone, paralysed with gallamine and mechanically ventilated and in which the right sinus and both aortic nerves had been cut and the left carotid sinus vascularly isolated. Later in each experiment, the head was artificially perfused with femoral arterial blood via the innominate artery. 2. Stimulation of the carotid body chemoreceptors with venous blood invariably caused a rise in regional cerebral blood flow whether the head was naturally or artificially perfused. This response was almost completely abolished if the VIIth cranial nerves were cut intracranially. 3. Regional cerebral blood flow varied inversely with carotid sinus pressure. 4. After the remaining (left) sinus nerve had been cut, the cerebral vascular response to hypoxia was negligible and the response to hypercapnia was markedly reduced. Blood flow then varied with perfusion pressure. 5. These results provide further evidence that cerebral blood vessels are reflexly controlled and that the peripheral arterial receptors are involved. Their action is most conspicuous in the vascular response to hypoxia and together with intrinsic factors in the cerebral vascular bed, they determine the size of the vascular response to changes in CO2 and pressure. PMID:4207655

Ponte, J.; Purves, M. J.

1974-01-01

304

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

NASA Astrophysics Data System (ADS)

Our purpose is to test if Pluronic fluorescent nanomicelles can be used for in vivo two-photon imaging of both the normal and the tumor vasculature. The nanomicelles were obtained after encapsulating a hydrophobic two-photon dye: di-stryl benzene derivative, in Pluronic block copolymers. Their performance with respect to imaging depth, blood plasma staining, and diffusion across the tumor vascular endothelium is compared to a classic blood pool dye Rhodamin B dextran (70 kDa) using two-photon microscopy. Pluronic nanomicelles show, like Rhodamin B dextran, a homogeneous blood plasma staining for at least 1 h after intravenous injection. Their two-photon imaging depth is similar in normal mouse brain, using 10 times less injected mass. In contrast with Rhodamin B dextran, no extravasation is observed in leaky tumor vessels due to their large size: 20-100 nm. In conclusion, Pluronic nanomicelles can be used as a blood pool dye, even in leaky tumor vessels. The use of Pluronic block copolymers is a valuable approach for encapsulating two-photon fluorescent dyes that are hydrophobic and not suitable for intravenous injection.

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

2011-03-01

305

Characterization, Localization and Patterning of Lymphatics and Blood Vessels in Oral Squamous Cell Carcinoma: A Comparative Study Using D2-40 and CD-34 IHC Marker  

PubMed Central

Objectives: Lymphatic metastasis has always been regarded as a major prognostic indicator for disease progression and as a guide for therapeutic strategies to oral squamous cell carcinoma (OSCC). Differentiating lymphatic vessels from blood vessels is difficult, partly due to lack of specific method for identifying lymphatics. A new lymphatic vessel reactive antibody D2-40 has been introduced recently. Here we examined immunohistochemical localization of lymphatic vessels and blood vessels using D2-40 and CD-34 respectively in different histological grades of OSCC. Their expression in intra-tumoural and peri-tumoural region was also compared. Materials and Methods: Forty two formalin-fixed paraffin-embedded tissue blocks of excised specimens of OSCC were immunohistochemically evaluated using D2-40 and CD-34 antibodies. Lymphatic vessel density (LVD) (D2-40 positivity) and micro vessel density (MVD) (CD34 positivity) in both intratumoural and peritumoural areas were assessed by hot spot method. Results: Regardless of histopathological differentiation, LVD and MVD in peritumoural areas were found greater than intratumoural areas (p>0.05). Interestingly, other than lymphatic vessels, D2-40 positivity was also detected in tumour cells as well as in basal layer of epithelium adjacent to OSCC. Two patterns of distribution of CD34 positive vessel - circumscribing type and penetrating type were also observed in the cancer nest area. Conclusion: D2-40 can be used as a marker to differentiate lymphatic vessels from blood vessels. Lymphatic and blood vessel proliferation might be much more extensive in the peritumoural area. D2-40 expression in epithelium adjacent to tumour indicates its role in the process of differentiation. Further, its expression in potential malignant disorder may provide better insight in predicting prognosis and pathogenesis of these lesions. PMID:25478456

Agarwal, Deshant; Bajpai, Manas; Gupta, Shailendra; Mathur, Nikunj; Vanaki, S S; Puranik, R S; Mittal, Manoj

2014-01-01

306

Blood vessel density and eNOS concentration in the chick embryo chorio-allantoic membrane: area under the air cell is different from the rest  

Microsoft Academic Search

vessels. An air cell is formed in the blunt end between the two membranes under the eggshell. It enlarges due to loss of water vapour during incubation. We hypothesised that CAM properties under the air cell may differ from those of the rest of the CAM. In the CAM of chicken eggs we studied the following parameters: blood vessel numerical

A. Ar; A. Reizis; I. Hammel

307

In-vivo imaging of blood flow in human retinal vessels using color Doppler optical coherence tomography  

NASA Astrophysics Data System (ADS)

Quantification of retinal blood flow may lead to a better understanding of the progression and treatment of several ocular disorders, including diabetic retinopathy, age- related macular degeneration, and glaucoma. Current techniques, such as fluorescein angiography and laser Doppler velocimetry are limited, failing to provide sufficient information to the clinician. Color Doppler optical coherence tomography (CDOCT) is a novel technique using coherent heterodyne detection for simultaneous cross- sectional imaging of tissue microstructure and blood flow. This technique is capable of high spatial and velocity resolution imaging in highly scattering media. We implemented CDOCT for retinal blood flow mapping in human subjects. No dilation of the pupil was necessary. CDOCT is demonstrated for determining bidirectional flow in sub- 100micrometers diameter vessels in the retina. Additionally, we calculated Doppler broadening using the variance of depth- resolved spectra to identify regions with large velocity gradients within the Xenopus heart. This technique may be useful in quantifying local tissue perfusion in highly vascular retinal tissue.

Yazdanfar, Siavash; Rollins, Andrew M.; Izatt, Joseph A.

1999-04-01

308

Selective photothermolysis of blood vessels following flashlamp-pumped pulsed dye laser irradiation: in vivo results and mathematical modelling are in agreement.  

PubMed

Laser therapy using the pulsed dye laser is the standard treatment for port-wine stains (PWS). But the mechanism of action has not been elucidated completely, yet. The dorsal skin-fold chamber model in hamsters was used to investigate the effects of laser treatment (lambda(em)=585 nm; pulse duration: 0.45 ms; fluence: 6 J per cm2) on blood vessels. Vessels (n=3394) were marked with FITC dextran (MW 150 kDa) and diameters (2-186 microm) were measured using intravital fluorescence microscopy up to 24 h following irradiation. Histology (H&E, TUNEL, CD31) was taken 1 or 24 h after irradiation. The experimental results were compared with the predictions of a mathematical model based on the finite-element method. Following irradiation treatment the number of unperfused vessels decreases with decreasing vessel diameter in vivo. Histology indicated a restriction of tissue injury to the irradiated area after 1 h. Blood vessels contained aggregated red blood cells. After 24 h tissue damage occurred also outside the irradiated area and thrombus formation was visible. These results were in agreement with the mathematical calculations. In addition to initial physical effects after pulsed dye laser treatment delayed biological processes contribute significantly to the reduction of perfused blood vessels. Because of incomplete photocoagulation of smaller blood vessels (diameter 2-16 microm) a complete bleaching of PWS seems to be unlikely. PMID:16098046

Babilas, Philipp; Shafirstein, Gal; Bumler, Wolfgang; Baier, Jrgen; Landthaler, Michael; Szeimies, Rolf-Markus; Abels, Christoph

2005-08-01

309

Comparative analysis of function of reproductive organs of cow and female reindeer. Cellular composition of blood in vessels of reproductive organs  

Microsoft Academic Search

Cellular composition of blood was studied in vessels of reproductive organs and jugular vein in females of reindeer and cow\\u000a depending on their physiological state. Physiological leukocytosis was revealed in reproductive organs of the animals, the\\u000a most expressed in reindeer. In both species, during the estrous cycle, in blood of vessels of reproductive organs the content\\u000a of lymphocytes and monocytes

M. F. Borisenkov; N. P. Mongalev

2006-01-01

310

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

PubMed

Primary vasculogenesis in chick embryos at the early somite stage (1-14 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 either the ventral (AV, VV, AD) or the dorsal (VC), vascular system. The mode of vascular formation was found to be identical in all these blood vessels, arising first in loco as isolated solid masses or cords composed of so-called angioblasts. The angioblasts at this developmental phase could be distinguished from underlying mesenchymal cells, exhibiting a relatively flat surface. The VV was recognized first on both sides of the anterior intestinal portal at the 4-somite stage, whereas the forming AD was identified on the ventral surface of the paired somites at the 6-somite stage, appearing almost simultaneously from the cranial to caudal somite regions. After the 8-somite stage, the AV was formed by transformation of one of the caudal plexuses spreading to the area vasculosa. In the 9-somite stage, the angioblastic cords of the VC appeared on the dorsal side of the mesoderm in the same manner as for other ventral vessels. This finding differs from the statement of a previous author that the VCis formed by longitudinal anastomosis of intersegmental diverticula of the AD. PMID:7340557

Hirakow, R; Hiruma, T

1981-01-01

311

Embolization of Hepatic Arterial Branches to Simplify Hepatic Blood Flow Before Yttrium 90 Radioembolization: A Useful Technique in the Presence of Challenging Anatomy  

SciTech Connect

Purpose: In the presence of variant hepatic arterial anatomy, obtaining whole-liver coverage with yttrium 90 (Y90) radioembolization may be challenging. The purpose of this study was to determine whether a technique whereby variant hepatic arterial branches are embolized and then Y90 is administered selectively into one remaining hepatic arterial branch results in whole-liver coverage and effective therapy. A retrospective comparison of treatment response was made between a group of patients who underwent this technique before Y90 administration and a group of patients who received standard Y90 administration as a single dose into the proper hepatic artery or in divided doses into the immediate hepatic artery branches. The rest of the workup and treatment were identical in both groups, including routine embolization of potential nonhepatic, nontarget vessels (e.g., the gastroduodenal artery). Methods: A total of 32 patients (mean age 56.9 years, range 39-77 years) treated with Y90 between June 2004 and March 2008 were analyzed. The primary malignancy was colorectal in 29, breast in 2, and cholangiocarcinoma in 1. Group 1 comprised 20 patients who had no alterations to their hepatic arterial supply. Group 2 comprised 12 cases who had undergone prior embolization of hepatic arterial branches before administration of Y90. The response to treatment was assessed by comparing standardized uptake value (SUV) on the pre- and postprocedure fludeoxyglucose positron emission tomographic studies of representative lesions within the right and left lobes of the liver. Results: In group 1, significant response (P < 0.001) was seen among right lobe lesions but not among left lobe lesions (P = 0.549). In group 2, there was a significant response among both right (P = 0.028) and left (P = 0.014) lobe lesions. No difference was found in the response of right lobe lesions (P = 0.726) between groups 1 and 2; a significantly greater response was found in group 2 compared to group 1 (P = 0.004) for left lobe lesions. Conclusion: Selective Y90 radioembolization after manipulation of hepatic arterial blood supply leads to an even distribution within the entire liver. When variations in hepatic arterial anatomy exist, this technique allows effective whole-liver radioembolization therapy from a single selective arterial injection.

Karunanithy, Narayan [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom); Gordon, Fabiana, E-mail: fabiana.gordon@imperial.ac.uk [Statistical Advisory Service, Imperial College (United Kingdom); Hodolic, Marina; Al-Nahhas, Adil [Imperial College Healthcare NHS Trust, Department of Nuclear Medicine (United Kingdom); Wasan, Harpreet S. [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Habib, Nagy [Imperial College Healthcare NHS Trust, Department of Surgery (United Kingdom); Tait, Nicholas P., E-mail: Paul.Tait@imperial.nhs.uk [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom)

2011-04-15

312

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot  

E-print Network

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 ...

Kastrup, Christian J.

313

[Diagnosis of latent atherosclerotic stenosing lesions of large cerebral blood vessels in the flight personnel].  

PubMed

In order to detect stenotic lesions of cerebral large vessels, 207 subjects, primarily pilots, were examined by ultrasonic Dopplerography. The first group with cerebral atherosclerosis at stage 1 included 90 pilots; 20 of them (22%) showed signs of stenotic lesions of the carotid and spinal arteries. The second group with cerebral atherosclerosis at stage II-III included 117 subjects; 14 of them exhibited interior carotid artery occlusion and 49 stenosis of one or several large vessels. Using clinical data, it was concluded that latent stenosis of cerebral large vessels are frequent in crew-members even at early stages of cerebral atherosclerosis and, therefore, may be risky for flight safety. Ultrasonic Dopplerography, being a fairly simple and accurate technique to detect stenotic vessels, is recommended for large-scale examinations of the flying personnel with cerebral atherosclerosis. PMID:6656194

Semenov, B Kh; Arapova, L V; Zhevlakova, L A; Parmenov-Trifilov, B I

1983-01-01

314

Blood vessel segmentation and width estimation in ultra-wide field scanning laser ophthalmoscopy  

PubMed Central

Features of the retinal vasculature, such as vessel widths, are considered biomarkers for systemic disease. The aim of this work is to present a supervised approach to vessel segmentation in ultra-wide field of view scanning laser ophthalmoscope (UWFoV SLO) images and to evaluate its performance in terms of segmentation and vessel width estimation accuracy. The results of the proposed method are compared with ground truth measurements from human observers and with existing state-of-the-art techniques developed for fundus camera images that we optimized for UWFoV SLO images. Our algorithm is based on multi-scale matched filters, a neural network classifier and hysteresis thresholding. After spline-based refinement of the detected vessel contours, the vessel widths are estimated from the binary maps. Such analysis is performed on SLO images for the first time. The proposed method achieves the best results, both in vessel segmentation and in width estimation, in comparison to other automatic techniques. PMID:25574441

Pellegrini, Enrico; Robertson, Gavin; Trucco, Emanuele; MacGillivray, Tom J.; Lupascu, Carmen; van Hemert, Jano; Williams, Michelle C.; Newby, David E.; van Beek, Edwin JR; Houston, Graeme

2014-01-01

315

Analysis of the effects of gravity and wall thickness in a model of blood flow through axisymmetric vessels.  

PubMed

The effects of gravitational forces and wall thickness on the behaviour of a model of blood flow through axisymmetric vessels were studied. The governing fluid dynamic equations were derived from the Navier-Stokes equations for an incompressible fluid and linked to a simple model of the vessel wall. A closed form of the hyperbolic partial differential equations was found, including a significant source term from the gravitational forces. The inclination of the vessel is modelled using a slope parameter that varied between -1 and 1. The wave speed was shown to be related to the wall thickness, and the time to first shock formation was shown to be directly proportional to this thickness. Two non-dimensional parameters were derived for the ratio of gravitational forces to viscous and momentum forces, respectively, and their values were calculated for the different types of vessel found in the human vasculature, showing that gravitational forces were significant in comparison with either viscous or momentum forces for every type of vessel. The steady-state solution of the governing equations showed that gravitational forces cause an increase in area of approximately 5% per metre per unit slope. Numerical simulations of the flow field in the aorta showed that a positive slope causes a velocity pulse to change in amplitude approximately linearly with distance: -4% per metre and +5% per metre for vessels inclined vertically upwards and downwards, respectively, in comparison with only +0.5% for a horizontal vessel. These simulations also showed that the change relative to the zero slope condition in the maximum rate of change of area with distance, which was taken to be a measure of the rate of shock formation, is proportional to both the slope and the wall thickness-to-inner radius ratio, with a constant of proportionality of 1.2. At a ratio of 0.25, typical of that found in human arteries, the distance to shock formation is thus decreased and increased by 30% for vessels inclined vertically downwards and upwards, respectively. Gravity and wall thickness thus have a significant impact on a number of aspects of the fluid and wall behaviour, despite conventionally being neglected. PMID:15587471

Payne, S J

2004-11-01

316

Well-balanced high-order solver for blood flow in networks of vessels with variable properties.  

PubMed

We present a well-balanced, high-order non-linear numerical scheme for solving a hyperbolic system that models one-dimensional flow in blood vessels with variable mechanical and geometrical properties along their length. Using a suitable set of test problems with exact solution, we rigorously assess the performance of the scheme. In particular, we assess the well-balanced property and the effective order of accuracy through an empirical convergence rate study. Schemes of up to fifth order of accuracy in both space and time are implemented and assessed. The numerical methodology is then extended to realistic networks of elastic vessels and is validated against published state-of-the-art numerical solutions and experimental measurements. It is envisaged that the present scheme will constitute the building block for a closed, global model for the human circulation system involving arteries, veins, capillaries and cerebrospinal fluid. PMID:23913466

Mller, Lucas O; Toro, Eleuterio F

2013-12-01

317

Direct evidence for the role of caveolin-1 and caveolae in mechanotransduction and remodeling of blood vessels.  

PubMed

Caveolae in endothelial cells have been implicated as plasma membrane microdomains that sense or transduce hemodynamic changes into biochemical signals that regulate vascular function. Therefore we compared long- and short-term flow-mediated mechanotransduction in vessels from WT mice, caveolin-1 knockout (Cav-1 KO) mice, and Cav-1 KO mice reconstituted with a transgene expressing Cav-1 specifically in endothelial cells (Cav-1 RC mice). Arterial remodeling during chronic changes in flow and shear stress were initially examined in these mice. Ligation of the left external carotid for 14 days to lower blood flow in the common carotid artery reduced the lumen diameter of carotid arteries from WT and Cav-1 RC mice. In Cav-1 KO mice, the decrease in blood flow did not reduce the lumen diameter but paradoxically increased wall thickness and cellular proliferation. In addition, in isolated pressurized carotid arteries, flow-mediated dilation was markedly reduced in Cav-1 KO arteries compared with those of WT mice. This impairment in response to flow was rescued by reconstituting Cav-1 into the endothelium. In conclusion, these results showed that endothelial Cav-1 and caveolae are necessary for both rapid and long-term mechanotransduction in intact blood vessels. PMID:16670769

Yu, Jun; Bergaya, Sonia; Murata, Takahisa; Alp, Ilkay F; Bauer, Michael P; Lin, Michelle I; Drab, Marek; Kurzchalia, Teymuras V; Stan, Radu V; Sessa, William C

2006-05-01

318

Intersublaminar Vascular Plexus: The Correlation of Retinal Blood Vessels With Functional Sublaminae of the Inner Plexiform Layer  

PubMed Central

Purpose. Interactions between vasculature and neurons provide important insight into the function of the nervous system, as well as into neurological diseases wherein these interactions are disrupted. This study characterizes a previously unreported retinal vascular plexus and examines potential sites of neurovascular interaction. Methods. Vascular, neuronal, and glial elements were visualized using immunohistochemical markers. The distribution of vascular layers was measured and compared across eccentricities. Intensity profiles were calculated from confocal image reconstructions to reveal the proximity of vasculature to neuronal and glial processes. Results. Retinal vasculature forms a plexus that coincides with the dendritic processes of OFF cholinergic amacrine cells within the inner plexiform layer. Across eccentricities, this plexus comprises approximately 8% of the total length of horizontally running blood vessels in the retina. Processes of Mller glia and OFF cholinergic amacrine cells colocalize with the blood vessels that form the intersublaminar plexus. Conclusions. In the retina, vasculature lacks autonomic control, but shows efficient local regulation. Although the source of this regulation is unclear, these results suggest that cholinergic amacrine cells and Mller glia may interact with the intersublaminar plexus to influence vasomotor activity. This may indicate a key role in modulating reciprocal interactions between neuronal activity and blood flow. PMID:24346172

Ivanova, Elena; Toychiev, Abduqodir H.; Yee, Christopher W.; Sagdullaev, Botir T.

2014-01-01

319

Effects of electrical stunning frequency and voltage combinations on the presence of engorged blood vessels in goose liver.  

PubMed

The purpose of this study was to investigate the influence of nine electrical stunning methods using various frequency and voltage combinations on the occurrence of engorged blood vessels in goose liver. Two hundred seventy Gourmaud geese (liver-type line SI 14) were slaughtered at 12 wk of age, in groups of 90 at three different times. Thirty birds each were subjected to one of the nine stunning methods. Neck cutting was performed immediately after stunning. The duration of exsanguination was 11 min. After completion of bleeding, the birds were scalded, defeathered manually, and kept refrigerated. At 1 d postmortem, the carcasses were eviscerated and cut up. From the slaughterhouse, the livers chilled in ice were transported to the cannery where they were weighed and graded at 2 d postmortem and were further processed. All of the veins and capillaries full of blood were removed from livers, because their presence was a hazard to product quality by causing discoloration of the canned liver, and the percentage of liver weight loss was then determined. The loss in liver weight due to removal of engorged blood vessels was reduced (P < 0.05) at 350 Hz, 70 to 90 V, and 80 to 85 mA when compared to the results obtained with any other stunning method tested. It was concluded that the use of high-frequency currents for electrical stunning of liver geese might have considerable commercial advantages. PMID:14653479

Turcsn, Zs; Varga, L; Szigeti, J; Turcsn, J; Csurk, I; Szalai, M

2003-11-01

320

Application of thrombin based fibrin glue and non-thrombin based batroxobin glue on intact human blood vessels: evidence for transmural thrombin activity.  

PubMed

An alternative method of uniting small diameter vessels to obtain tissue union while limiting the thrombogenic effect of suture placement at a vessel anastomosis involves the use of a thrombin based fibrin glue as a surgical sealant. This investigation addresses whether the in vitro application of a thrombin based glue (TG), or batroxobin glue (BG), a non-thrombin based glue made with the snake venom enzyme batroxobin, alters intravascular platelet deposition (PD) or cleaves blood fibrinogen, as measured by fibrinopeptide A (FPA) production, when the respective glue is applied to the external surface of an intact human placental artery or an artery with an anastomosis. When TG was applied to the adventitial surface of an intact vessel or an anastomosis (n = 7) of control and experimental vessels, there was a significant increase in intraluminal platelet deposition, an effect not realized with BG (n = 12, intact vessel TG p = 0.01, BG p = 0.66, anastomosis TG p <0.01, BG p <0.01). Both TG and BG significantly increased FPA levels when human whole blood was perfused through both intact vessels or vessels containing an anastomosis when compared to control vessels (intact vessel TG and BG p <0.01, anastomosis TG and BG p <0.01). Labelled thrombin studies document the rapid passage of thrombin through an intact vessel wall or vessels with an anastomosis when TG was applied to the adventitial surface of the vessel. The data suggest that TG and BG are drug delivery systems for their respective enzymes that either pass through or transfer a message across not only a surgically created anastomosis, but also an intact vessel wall. PMID:9268200

Dascombe, W H; Dumanian, G; Hong, C; Heil, B V; Labadie, K; Hessel, B; Blombck, B; Johnson, P C

1997-08-01

321

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

PubMed Central

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

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

2014-01-01

322

Mapping of spatial distribution of superficial blood vessels in human skin by double correlation analysis of optical coherence tomography images  

NASA Astrophysics Data System (ADS)

2D/3D spatial distribution of superficial blood vessels in human skin in vivo was conducted by double correlation analysis of the swept source Optical Coherence Tomography (OCT) images. An adaptive Wiener filtering technique has been employed to remove background noise and increase the overall quality of the OCT images acquired experimentally. Correlation Mapping and Fourier domain correlation approaches have been subsequently applied to enhance spatial resolution of images of vascular network in human skin. The analysis of images performed on Graphics Processing Units (GPUs) utilizing the recently developed Compute Unified Device Architecture (CUDA) framework.

Doronin, A.; Botting, S.; Meglinski, M.; Jentoft, K.; Meglinski, I.

2013-02-01

323

Mechanotransduction in Vascular Endothelial Cells: Mechanisms and Implications The ability of arterial endothelial cells, the cells lining the inner surfaces of blood vessels, to  

E-print Network

of arterial endothelial cells, the cells lining the inner surfaces of blood vessels, to respond to mechanicalMechanotransduction in Vascular Endothelial Cells: Mechanisms and Implications The ability forces associated with blood flow is essential for normal vascular function. Abnormalities in endothelial

Mayberry, Marty

324

Complete radio frequency ablation of hepatocellular carcinoma adjacent to the main bile duct and blood vessels between the first and the second hepatic portal.  

PubMed

In cases where hepatocellular carcinoma cannot be surgically removed either due to the capacity of hepatic functional reserve or the special location of the tumor, a radiofrequency ablation (RFA) is recognized to be an effective and minimally invasive treatment. However, when the tumor is adjacent to the main bile duct and blood vessels, it is feared that due to the "heat-sink effect" of the blood and the possible damage to the duct and blood vessels, complete tumor ablation is hard to achieve. We report here a case of complete RFA of hepatocellular carcinoma, adjacent to the main bile duct and blood vessels between the first and the second hepatic portal, with emphasis on the safety of the approach for complete ablation of the tumor. PMID:23179404

Kai, Jiang; Ming, Su; Yang, Liu; Wen-zhi, Zhang; Xiang-qian, Zhao; Zhe, Liu; Wen-ping, Lv; Zhi-wei, Liu; Jia-hong, Dong

2013-06-01

325

Assessing blood vessel abnormality via extracting scattering coefficients from OCT images  

Microsoft Academic Search

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

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

2003-01-01

326

Gabor wavelet based blood vessel segmentation in retinal images using kernel classifiers  

Microsoft Academic Search

The retina is an important field in the medical treatment of pathologies. Segmentation of the vasculature in retinal fundus images plays an important role in the diagnosis of many eye diseases such as hypertension, arteriosclerosis and blindness caused by diabetes. Comparison of kernel classifiers for the vessel segmentation is presented in this work. Kernel based classifier such as Support Vector

D Selvathi; P Lalitha Vaishnavi

2011-01-01

327

Retinal Blood Vessel Segmentation Using Line Operators and Support Vector Classification  

Microsoft Academic Search

In the framework of computer-aided diagnosis of eye diseases, retinal vessel segmentation based on line operators is proposed. A line detector, previously used in mammography, is applied to the green channel of the retinal image. It is based on the evaluation of the average grey level along lines of fixed length passing through the target pixel at different orientations. Two

Elisa Ricci; Renzo Perfetti

2007-01-01

328

Angiogenesis in the developing spinal cord: blood vessel exclusion from neural progenitor region is mediated by VEGF and its antagonists.  

PubMed

Blood vessels in the central nervous system supply a considerable amount of oxygen via intricate vascular networks. We studied how the initial vasculature of the spinal cord is formed in avian (chicken and quail) embryos. Vascular formation in the spinal cord starts by the ingression of intra-neural vascular plexus (INVP) from the peri-neural vascular plexus (PNVP) that envelops the neural tube. At the ventral region of the PNVP, the INVP grows dorsally in the neural tube, and we observed that these vessels followed the defined path at the interface between the medially positioned and undifferentiated neural progenitor zone and the laterally positioned differentiated zone. When the interface between these two zones was experimentally displaced, INVP faithfully followed a newly formed interface, suggesting that the growth path of the INVP is determined by surrounding neural cells. The progenitor zone expressed mRNA of vascular endothelial growth factor-A whereas its receptor VEGFR2 and FLT-1 (VEGFR1), a decoy for VEGF, were expressed in INVP. By manipulating the neural tube with either VEGF or the soluble form of FLT-1, we found that INVP grew in a VEGF-dependent manner, where VEGF signals appear to be fine-tuned by counteractions with anti-angiogenic activities including FLT-1 and possibly semaphorins. These results suggest that the stereotypic patterning of early INVP is achieved by interactions between these vessels and their surrounding neural cells, where VEGF and its antagonists play important roles. PMID:25585380

Takahashi, Teruaki; Takase, Yuta; Yoshino, Takashi; Saito, Daisuke; Tadokoro, Ryosuke; Takahashi, Yoshiko

2015-01-01

329

Angiogenesis in the Developing Spinal Cord: Blood Vessel Exclusion from Neural Progenitor Region Is Mediated by VEGF and Its Antagonists  

PubMed Central

Blood vessels in the central nervous system supply a considerable amount of oxygen via intricate vascular networks. We studied how the initial vasculature of the spinal cord is formed in avian (chicken and quail) embryos. Vascular formation in the spinal cord starts by the ingression of intra-neural vascular plexus (INVP) from the peri-neural vascular plexus (PNVP) that envelops the neural tube. At the ventral region of the PNVP, the INVP grows dorsally in the neural tube, and we observed that these vessels followed the defined path at the interface between the medially positioned and undifferentiated neural progenitor zone and the laterally positioned differentiated zone. When the interface between these two zones was experimentally displaced, INVP faithfully followed a newly formed interface, suggesting that the growth path of the INVP is determined by surrounding neural cells. The progenitor zone expressed mRNA of vascular endothelial growth factor-A whereas its receptor VEGFR2 and FLT-1 (VEGFR1), a decoy for VEGF, were expressed in INVP. By manipulating the neural tube with either VEGF or the soluble form of FLT-1, we found that INVP grew in a VEGF-dependent manner, where VEGF signals appear to be fine-tuned by counteractions with anti-angiogenic activities including FLT-1 and possibly semaphorins. These results suggest that the stereotypic patterning of early INVP is achieved by interactions between these vessels and their surrounding neural cells, where VEGF and its antagonists play important roles. PMID:25585380

Takahashi, Teruaki; Takase, Yuta; Yoshino, Takashi; Saito, Daisuke; Tadokoro, Ryosuke; Takahashi, Yoshiko

2015-01-01

330

NCI-CCR Pediatric Oncology Branch: Blood and Marrow Transplant - Staff  

Cancer.gov

Skip to Main Content CCR Home | About CCR | CCR Intranet Main Navigation Referrals For Patients For Physicians For Prospective Trainees For Scientists News Quick Links Home Referring a Patient Patients and Families Scientific Programs - Blood & Marrow

331

The adrenergic innervation of the vessels supplying and draining the gastrointestinal tract  

Microsoft Academic Search

The fluorescence histochemical method has been used to investigate the adrenergic innervation of the vessels of the gastrointestinal tract. Both stretch preparations and sections of blood vessels taken from cats, guinea-pigs, rabbits and rats were examined. A dense innervation of the major mesenteric arteries and their branches was found. Most of the nerve fibres are at the adventitio-medial border, but

J. B. Furness

1971-01-01

332

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

NASA Astrophysics Data System (ADS)

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.

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

2003-06-01

333

Resveratrol affects histone 3 lysine 27 methylation of vessels and blood biomarkers in DOCA salt-induced hypertension.  

PubMed

Hypertension is a risk factor for the cardiovascular diseases. Although, several drugs are used to treat hypertension, the success of the antihypertensive therapy is limited. Resveratrol decreases blood pressure in animal models of hypertension. This study researched the mechanisms behind the effects of resveratrol on hypertension. Hypertension was induced by using the deoxycorticosterone acetate (DOCA)-induced (15mg/kg twice per week, subcutaneously) salt-sensitive hypertension model of Wistar rats. Hypertension caused a decrease in endothelium-dependent relaxations of the isolated thoracic aorta. Resveratrol treatment (50mg/l in drinking water) prevented DOCA salt-induced hypertension, but did not improve endothelial dysfunction. Plasma nitric oxide (NO), asymmetric dimethylarginine (ADMA), total antioxidant capacity (TAC) and hydrogen sulfide (H2S) levels were not changed by DOCA salt application. However, treatment of resveratrol significantly decreased ADMA and increased TAC and H2S levels. NO level in circulation was not significantly changed by resveratrol. DOCA salt application and resveratrol treatment also caused an alteration in the epigenetic modification of vessels. Staining pattern of histone 3 lysine 27 methylation (H3K27me3) in the aorta and renal artery sections was changed. These results show that preventive effect of resveratrol on DOCA salt-induced hypertension might due to its action on the production of some blood biomarkers and the epigenetic modification of vessels that would focus upon new aspect of hypertension prevention and treatment. PMID:25234650

Han, Sevtap; Uludag, Mecit Orhan; Usanmaz, Suzan Emel; Ayaloglu-Butun, Fatma; Akcali, Kamil Can; Demirel-Yilmaz, Emine

2015-01-01

334

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

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

335

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

Microsoft Academic Search

THE endothelial cell-specific vascular endothelial growth factor (VEGF)1-5 and its cellular receptors Flt-1 (refs 6,7) and Flk-1 (refs 8,9) have been implicated in the formation of the embryonic vasculature. This is suggested by their colocalized expression during embryogenesis10,11 and the impaired vessel formation in Flk-1 (ref. 12) and Flt-1 (ref. 13) deficient embryos. However, because Flt-1 also binds placental growth

Peter Carmeliet; Valrie Ferreira; Georg Breier; Saskia Pollefeyt; Lena Kieckens; Marina Gertsenstein; Michaela Fahrig; Ann Vandenhoeck; Kendraprasad Harpal; Carmen Eberhardt; Cathrine Declercq; Judy Pawling; Lieve Moons; Dsir Collen; Werner Risau; Andras Nagy

1996-01-01

336

PIV and digital holography for measuring blood flows and vessel wall dynamics  

NASA Astrophysics Data System (ADS)

In this work endoscopy has been combined with high speed PIV and holographic interferometry for flow velocity and wall deformation measurement of different vessels. Endoscopes have been used for illumination and/or recording of PIV images and digital holograms. High speed PIV has been applied to evaluate the influence of an antithrombotic filter in a vena cava model flow. Qualitative wall deformation has been obtained using digital holography in a vein model and in a real sheep aorta.

Arvalo, Laura; Roche, Eva; Palero, Virginia; Martnez, Miguel ngel; Arroyo, M. Pilar

2013-11-01

337

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

NASA Technical Reports Server (NTRS)

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.

Kasimtsev, A. A.

1980-01-01

338

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

NASA Astrophysics Data System (ADS)

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.

LeBlanc, Serge Emile

339

Evaluation of sildenafil pressurized metered dose inhalers as a vasodilator in umbilical blood vessels of chicken egg embryos.  

PubMed

Sildenafil citrate is a selective phosphodiesterase-5 inhibitor used for the treatment for erectile dysfunction and pulmonary hypertension. The delivery of sildenafil directly to the lung could have several advantages over conventional treatments for pulmonary hypertension because of the local delivery, a more rapid onset of response, and reduced side effects. The major problem of sildenafil citrate is its limited solubility in water. Sildenafil citrate was complexed with cyclodextrins (CDs) to enhance its water solubility prior to development as an inhaled preparation. Four sildenafil citrate inhaled formulations were prepared with the aid of HP-?-CD (#1), ?-CD (#2) and ?-CD (#3) and their effects were compared with the formulations without CDs (#4). The sildenafil citrate pressurized metered dose inhalers (pMDI) used ethanol as a solvent, PEG400 as a stabilizing agent, sorbitan monooleate as a surfactant and HFA-134a as a propellant. All formulations consisted of sildenafil citrate equivalent to a sildenafil content of 20?g/puff. These products were evaluated according to a standard guideline of inhalation products. Vasodilation testing was performed to investigate the efficacy of sildenafil pMDIs in relieving a vasoconstricted umbilical blood vessel of the chicken egg embryo. The sildenafil contents of the pMDI formulations #1-#3 were within the acceptance criteria (80-120%). The emitted doses (ED) were 102.311.5%, the fine particle fractions (FPF) were 60.55.6% and the mass median aerodynamic diameters (MMAD) were 2.30.3?m. The vasodilatory activity of those formulations reduced umbilical blood pressure by 67.1-73.7% after treatment by intravenous injection whereas only a 50.1-58.0% reduced blood pressure was obtained after direct spraying of the sildenafil pMDI containing CDs. With sildenafil formulations of a pMDI without CD the blood pressure was reduced by only 39.0% (P-value<0.05). The available sildenafil in the blood vessels of chicken egg embryos after spraying sildenafil-CDs pMDIs was within the range of 751-825ng/mL which was much higher than that of a sildenafil only pMDI. PMID:24036276

Sawatdee, Somchai; Hiranphan, Phetai; Laphanayos, Kampanart; Srichana, Teerapol

2014-01-01

340

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

PubMed

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

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

341

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

PubMed Central

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 fluidstructure 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

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

2011-01-01

342

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

NASA Astrophysics Data System (ADS)

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.

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

2009-11-01

343

Similarity of vasorelaxant effects of natriuretic peptides in isolated blood vessels of salmonids.  

PubMed

Natriuretic peptides (NPs) have been implicated in cardiovascular regulation in rainbow trout (Oncorhyncus mykiss), and it has been observed that the vasorelaxant activity of distinct trout and human NPs is similar in isolated trout arteries. This study characterizes the response of a variety of vessels from rainbow trout and other salmonids to different NPs. The effects of heterologous (rat atrial and human atrial) and homologous (rainbow trout atrial and rainbow trout ventricular) NPs were examined in precontracted efferent branchial arteries from rainbow trout (O. mykiss, Kamloops strain), lake whitefish (Coregonus clupeaformis), and in rainbow trout celiacomesenteric arteries and anterior cardinal veins. The response to mammalian NPs was also examined in efferent branchial arteries from the steelhead (O. mykiss, Skamania strain), coho salmon (Oncorhyncus kisutch), brook trout (Salvelinus fontinalis), and brown trout (Salmo trutta). In general, there were relatively few differences that were species, peptide, or vessel specific. There was no difference in the sensitivity (concentration producing a half-maximal response EC(50)) or efficacy (percent relaxation, i.e., E(max)) of trout or whitefish efferent branchial arteries to any NP, except human NP, which was significantly less effective (greater EC(50) and lower E(max)) in whitefish arteries. There were no differences in E(max) of mammalian NPs in efferent branchial arteries from any species, and only coho and brook trout had significantly different EC(50)'s (coho, 1.0+/-0.2 nM; brook trout, 4. 2+/-0.6 nM; and other species, from 1.9 to 3.5 nM). Rainbow and coho anterior cardinal veins were less sensitive than arteries to mammalian NPs (EC(50)'s; 8.8+/-2.0, 2.0+/-0.1 vs. 3.0+/-0.9, 1.0+/-0. 2, respectively), whereas brown trout veins were more sensitive (1. 0+/-0.2, 3.5+/-1.3, respectively). Sodium nitroprusside (SNP), which activates soluble guanylate cyclase, was vasodilatory, albeit significantly less potent than all NPs, in efferent branchial arteries of all species. SNP was significantly more potent in trout than whitefish efferent branchial arteries, whereas it was equally efficacious in these vessels. These results demonstrate that multiple vessels from various salmonids are similarly responsive to the vasorelaxant effects of a variety of NPs and that the salmonid NP receptor has relatively little ability to discriminate between homologous and heterologous peptides. We conclude that the vascular NP receptor complex is highly conserved among salmonids. Further, salmonids utilize cyclic guanosine monophosphate (cGMP) elevations for reductions of vascular tonus by both particulate and soluble guanylate cyclase pathways. PMID:11009403

Smith, M P; Takei, Y; Olson, K R

2000-01-01

344

The Flk1-myr::mCherry mouse as a useful reporter to characterize multiple aspects of ocular blood vessel development and disease  

PubMed Central

The highly vascularized mouse eye is an excellent model system in which to elucidate the molecular genetic basis of blood vessel development and disease. However, the analysis of ocular vessel defects has traditionally been derived from fixed tissue which fails to account for dynamic events such as blood flow and cell migration. To overcome the limitations of static analysis, tremendous advances in imaging technology and fluorescent protein reporter mouse lines now enable the direct visualization of developing cells in vivo. Here, we demonstrate that the Flk1-myr::mCherry transgenic mouse is an extremely useful live reporter with broad applicability to retinal, hyaloid and choroid vascular research. PMID:19253403

Poch, Ross A.; Larina, Irina V.; Scott, Melissa L.; Saik, Jennifer E.; West, Jennifer L.; Dickinson, Mary E.

2010-01-01

345

Recovery from mild hypothermia can be accelerated by mechanically distending blood vessels in the hand  

Microsoft Academic Search

follows that removal of the vasoconstrictive blockade to heat exchange would facilitate transfer of heat from the skin to the body core in hypothermic individuals. The purpose of this study was to determine to what extent heat transfer to the thermal core of a hypothermic individual could be enhanced by increasing blood flow through the skin area to which exogenous

DENNIS GRAHN; JOHN G. BROCK-UTNE; DONALD E. WATENPAUGH; H. CRAIG HELLER

346

Developmental origins of aging in brain and blood vessels: an overview  

Microsoft Academic Search

Emerging evidence suggests a remarkable convergence of inflammatory mechanisms in the etiology of cardiovascular disease and Alzheimer disease. A broad set of NSAIDs and statins used to reduce the risk of vascular occlusion and to slow atherogensis may also be protective for Alzheimer disease. Elevated blood levels of C-reactive protein are risk factors for cardiovascular disease and possibly for Alzheimer

Caleb E. Finch

2005-01-01

347

Storage of radial artery grafts in blood increases vessel reactivity to vasoconstrictors in vitro  

Microsoft Academic Search

Background. Although prone to spasm, the radial artery (RA) is commonly used as a graft in coronary artery bypass surgery (CABG). Successful use of the RA as a graft is dependent on techniques to manage vasospasm during operation. We routinely store the RA in a papaverine blood solution after harvesting, a procedure which might damage the endothelium and predispose the

James Tatoulis; Guang-Chi Jiang; James D Moffatt; Thomas M Cocks

1999-01-01

348

A Phenomenological Model for Mechanically Mediated Growth, Remodeling, Damage, and Plasticity of Gel-Derived Tissue Engineered Blood Vessels  

PubMed Central

Mechanical stimulation has been shown to dramatically improve mechanical and functional properties of gel-derived tissue engineered blood vessels (TEBVs). Adjusting factors such as cell source, type of extracellular matrix, cross-linking, magnitude, frequency, and time course of mechanical stimuli (among many other factors) make interpretation of experimental results challenging. Interpretation of data from such multifactor experiments requires modeling. We present a modeling framework and simulations for mechanically mediated growth, remodeling, plasticity, and damage of gel-derived TEBVs that merge ideas from classical plasticity, volumetric growth, and continuum damage mechanics. Our results are compared with published data and suggest that this model framework can predict the evolution of geometry and material behavior under common experimental loading scenarios. PMID:19831486

Raykin, Julia; Rachev, Alexander I.

2011-01-01

349

Spectrophotometric measurements of human tissues for the detection of subjacent blood vessels in an endonasal endoscopic surgical approach.  

PubMed

Thin slices of human tissues are characterized concerning reflection and transmission in a wavelength range from 400 to 1700 nm. The results are primarily useful to find a wavelength for the detection of subjacent blood vessels during surgical procedures, especially neurological surgery. The measurements have been conducted using a customized measuring station, utilizing two halogen bulb lamps and two spectrometers. This paper focuses on creating a data base with the optical properties of artery, brain, bone, nasal mucosa, and nerve. The spectral distributions are compared among each other, similarities and differences are pointed out. Each tissue has got unique spectral characteristics, whereas typical absorption bands can be found in the overall tissues, especially hemoglobin and water absorption bands. The reflectivity maxima are typically located in the red or near-infrared. All the transmission maxima are located between 1075 nm and 1100 nm. The measurements have been conducted at the Institute of Anatomy at the University of Leipzig. PMID:22778075

Ernstberger, Markus; Boeswetter, Pascal; Baselt, Tobias; Ebert, Frank; Basan, Fabiola; Steinke, Hanno; Hammer, Niels; Grunert, Ronny; Hartmann, Peter

2013-04-01

350

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

NASA Astrophysics Data System (ADS)

A new approach to carbon monoxide poisoning treatment based on laser-induced photodissociation of the carboxyhemoglobin is proposed. Using the simple model of laser tissue interaction the action spectra of laser radiation on carboxyhemoglobin of cutaneous blood vessels has been calculated. The results of the calculatoins indicate that there is a relatively narrow spectral range in the visible region where one could effectively irradiate carboxyhemoglobin through the tissue not in a deep distances. In the case of deeper penetration, the action spectra of laser radiation shifts toward the longer wavelength region. Despite the similarity of the carboxyhemoglobin and oxyhemoglobin action spectra, the significant difference in quantum yields of photodissociation makes possible to develop an effective method of carbon monoxide poisoning treatment.

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

2005-04-01

351

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

PubMed Central

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

Elinson, Richard P.; Stewart, James R.

2014-01-01

352

Mechanical properties of completely autologous human tissue engineered blood vessels compared to human saphenous vein and mammary artery  

PubMed Central

We have previously reported initial clinical feasibility with our small diameter tissue engineered blood vessel (TEBV). Here we present in vitro results of the mechanical properties of the TEBVs of the first 25 patients enrolled in an arterio-venous (A-V) shunt safety trial, and compare these properties with those of risk-matched human vein and artery. TEBV average burst pressures (3,490 +/? 892 mmHg, n=230) were higher than native saphenous vein (SV) (1,599 +/? 877 mmHg, n=7), and not significantly different than native internal mammary artery (IMA) (3,196 +/? 1,264 mmHg, n=16). Suture retention strength for the TEBVs (152 +/? 50 gmf) was also not significantly different than IMA (138 +/? 50 gmf). Compliance for the TEBVs prior to implantation (3.4 +/? 1.6 %/100 mmHg) was lower than IMA (11.5 +/? 3.9 %/100 mmHg). By 6 months post-implant, the TEBV compliance (8.8 +/? 4.2 %/100 mmHg, n=5) had increased to values comparable to IMA, and showed no evidence of dilation or aneurysm formation. With clinical time points beyond 21 months as an A-V shunt without intervention, the mechanical tests and subsequent lot release criteria reported here would seem appropriate minimum standards for clinical use of tissue engineered vessels. PMID:19111338

Konig, Gerhardt; McAllister, Todd N; Dusserre, Nathalie; Garrido, Sergio A; Iyican, Corey; Marini, Alicia; Fiorillo, Alex; Avila, Hernan; Wystrychowski, Wojciech; Zagalski, Krzysztof; Maruszewski, Marcin; Jones, Alyce Linthurst; Cierpka, Lech; de la Fuente, Luis M; LHeureux, Nicolas

2009-01-01

353

Mechanical properties of completely autologous human tissue engineered blood vessels compared to human saphenous vein and mammary artery.  

PubMed

We have previously reported the initial clinical feasibility with our small diameter tissue engineered blood vessel (TEBV). Here we present in vitro results of the mechanical properties of the TEBVs of the first 25 patients enrolled in an arterio-venous (A-V) shunt safety trial, and compare these properties with those of risk-matched human vein and artery. TEBV average burst pressures (3490+/-892 mmHg, n=230) were higher than native saphenous vein (SV) (1599+/-877 mmHg, n=7), and not significantly different from native internal mammary artery (IMA) (3196+/-1264 mmHg, n=16). Suture retention strength for the TEBVs (152+/-50 gmf) was also not significantly different than IMA (138+/-50 gmf). Compliance for the TEBVs prior to implantation (3.4+/-1.6%/100 mmHg) was lower than IMA (11.5+/-3.9%/100 mmHg). By 6 months post-implant, the TEBV compliance (8.8+/-4.2%/100 mmHg, n=5) had increased to values comparable to IMA, and showed no evidence of dilation or aneurysm formation. With clinical time points beyond 21 months as an A-V shunt without intervention, the mechanical tests and subsequent lot release criteria reported here would seem appropriate minimum standards for clinical use of tissue engineered vessels. PMID:19111338

Konig, Gerhardt; McAllister, Todd N; Dusserre, Nathalie; Garrido, Sergio A; Iyican, Corey; Marini, Alicia; Fiorillo, Alex; Avila, Hernan; Wystrychowski, Wojciech; Zagalski, Krzysztof; Maruszewski, Marcin; Jones, Alyce Linthurst; Cierpka, Lech; de la Fuente, Luis M; L'Heureux, Nicolas

2009-03-01

354

Vessel-specific quantification of blood oxygenation with T2-Relaxation-Under-Phase-Contrast (TRU-PC) MRI  

PubMed Central

Purpose Measurement of venous oxygenation (Yv) is a critical step toward quantitative assessment of brain oxygen metabolism, a key index in many brain disorders. The present study aims to develop a non-invasive, rapid, and reproducible method to measure Yv in a vessel-specific manner. Theory The method, T2-Relaxation-Under-Phase-Contrast (TRU-PC) MRI, utilizes complex subtraction of phase-contrast to isolate pure blood signal, applies non-slice-selective T2-preparation to measure T2, and converts T2 to oxygenation using a calibration plot. Methods Following feasibility demonstration, several technical aspects were examined, including validation with an established global Yv technique, test-retest reproducibility, sensitivity to detect oxygenation changes due to hypoxia and caffeine challenges, applicability of EPI acquisition to shorten scan duration, and ability to study veins with a caliber of 12 mm. Results TRU-PC was able to simultaneously measure Yv in all major veins in the brain, including sagittal sinus, straight sinus, great vein, and internal cerebral vein. TRU-PC results showed an excellent agreement with the reference technique, high sensitivity to oxygenation changes, and test-retest variability of 3.51.0%. The use of segmented-EPI was able to reduce the scan duration to 1.5 minutes. It was also feasible to study pial veins and deep veins. Conclusion TRU-PC MRI is a promising technique for vessel-specific oxygenation measurement. PMID:23568830

Krishnamurthy, Lisa C.; Liu, Peiying; Ge, Yulin; Lu, Hanzhang

2014-01-01

355

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

PubMed Central

Endothelial Wnt/?-catenin signaling is necessary for angiogenesis of the central nervous system and bloodbrain 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/?-cateninDll4/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

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

356

The effects of nifedipine on alpha 2-adrenoceptor-mediated contractions in several isolated blood vessels from the rabbit.  

PubMed Central

1. The effects of the dihydropyridine calcium channel blocker, nifedipine, on noradrenaline-induced contractile responses have been examined in several isolated blood vessels from the rabbit, with particular emphasis on responses mediated via postjunctional alpha 2-adrenoceptors. 2. In the isolated renal vein, ear vein, distal saphenous artery, saphenous vein and plantaris vein, 0.1 microM and 1 microM nifedipine reduced responses elicited by 54 mM KCl by more than 70%. The remaining responses were abolished by alpha-adrenoceptor blockade, suggesting the involvement of noradrenaline released from neurones activating a dihydropyridine-resistant mechanism. 3. In the renal vein (alpha 1-), ear vein (predominantly alpha 2-), distal saphenous artery (alpha 1- greater than alpha 2-), saphenous vein and plantaris vein (alpha 2- greater than alpha 1-), 0.01 microM and 0.1 microM nifedipine produced concentration-related reductions in the maximum response to noradrenaline. However, 1 microM nifedipine was no more effective than 0.1 microM nifedipine and the reduction in the maximum varied from 10-25% of the control response. Thus, a sizeable component of the alpha-adrenoceptor-mediated response in all blood vessels is resistant to dihydropyridine calcium channel blockers and this appears to be unrelated to the alpha-adrenoceptor subtype involved. 4. Following irreversible inactivation of alpha 1-adrenoceptors and isolation of functional alpha 2-adrenoceptors in the saphenous vein, plantaris vein and distal saphenous artery (the latter requiring the presence of angiotensin II), the effect of nifedipine on responses to noradrenaline was increased. However, a component of the alpha 2-adrenoceptor response in each preparation was present even after the concentration of nifedipine was increased to 1 microM.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1653075

Dunn, W. R.; Daly, C. J.; McGrath, J. C.; Wilson, V. G.

1991-01-01

357

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

NASA Technical Reports Server (NTRS)

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.

Macovski, A.

1978-01-01

358

Vessel Segmentation and Blood Flow Simulation Using Level-Sets and Embedded Boundary Methods  

SciTech Connect

In this article we address the problem of blood flow simulation in realistic vascular objects. The anatomical surfaces are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of pathological objects such as aneurysms and stenoses. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier-Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element gridding of the whole volume, our method directly simulates the blood-flow inside the extracted surface without losing any complicated details and without building additional grids.

Deschamps, T; Schwartz, P; Trebotich, D; Colella, P; Saloner, D; Malladi, R

2004-12-09

359

Evolution of Retinal Blood Vessel Segmentation Methodology Using Wavelet Transforms for Assessment of Diabetic Retinopathy  

Microsoft Academic Search

Diabetes is a chronic disease that affects the bodys capacity to regulate the amount of sugar in the blood. One in twenty\\u000a Australians are affected by diabetes, but this figure is conservative, due to the presence of subclinical diabetes, where\\u000a the disease is undiagnosed, yet is already damaging the body without manifesting substantial symptoms. This incidence rate\\u000a is not confined

D. Cornforth; H. Jelinek; M. Cree; J. Leandro; J. Soares; R. Cesar

360

Ex vivo blood vessel imaging using ultrasound-modulated optical microscopy  

PubMed Central

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

Kothapalli, Sri-Rajasekhar; Wang, Lihong V.

2009-01-01

361

Simultaneous two-photon imaging of oxygen and blood flow in deep cerebral vessels  

PubMed Central

Uncovering principles that regulate energy metabolism in the brain requires mapping of partial pressure of oxygen (PO2) and blood flow with high spatial and temporal resolution. Using two-photon phosphorescence lifetime microscopy (2PLM) and the oxygen probe PtP-C343, we show that PO2 can be accurately measured in the brain at depths up to 300 ?m with micron-scale resolution. In addition, 2PLM allowed simultaneous measurements of blood flow and of PO2 in capillaries with less than one-second temporal resolution. Using this approach, we detected erythrocyte-associated transients (EATs) in oxygen in the rat olfactory bulb and showed the existence of diffusion-based arterio-venous shunts. Sensory stimulation evoked functional hyperemia, accompanied by an increase in PO2 in capillaries and by a biphasic PO2 response in the neuropil, consisting of an initial dip and a rebound. 2PLM of PO2 opens new avenues for studies of brain metabolism and blood flow regulation. PMID:21642977

Lecoq, Jrme; Parpaleix, Alexandre; Roussakis, Emmanuel; Ducros, Mathieu; Houssen, Yannick Goulam; Vinogradov, Sergei A; Charpak, Serge

2012-01-01

362

An Agent-Based Model of the Response to Angioplasty and Bare-Metal Stent Deployment in an Atherosclerotic Blood Vessel  

PubMed Central

Purpose While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques. The presented model is intended to demonstrate the bodys response to the intervention and to explore how different vessel geometries or stent arrangements may affect restenosis development. Methods The model was created on a two-dimensional grid space. It utilizes the post-procedural vessel lumen diameter and stent information as its input parameters. The simulation starting point of the model is an atherosclerotic vessel after an angioplasty and stent implantation procedure. The model subsequently generates the final lumen diameter, percent change in lumen cross-sectional area, time to lumen diameter stabilization, and local concentrations of inflammatory cytokines upon simulation completion. Simulation results were directly compared with the results from serial imaging studies and cytokine levels studies in atherosclerotic patients from the relevant literature. Results The final lumen diameter results were all within one standard deviation of the mean lumen diameters reported in the comparison studies. The overlapping-stent simulations yielded results that matched published trends. The cytokine levels remained within the range of physiological levels throughout the simulations. Conclusion We developed a novel computational model that successfully simulated the development of restenosis in a blood vessel following an angioplasty and bare-metal stent deployment based on the characteristics of the vessel cross-section and stent. A further development of this model could ultimately be used as a predictive tool to depict patient outcomes and inform treatment options. PMID:24732072

Curtin, Antonia E.; Zhou, Leming

2014-01-01

363

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 ...

364

Blood Thinners  

MedlinePLUS

If you have some kinds of heart or blood vessel disease, or if you have poor blood flow to your brain, your doctor may recommend that you take a blood thinner. Blood thinners reduce the risk of heart ...

365

Analysis of trajectories for targeting of magnetic nanoparticles in blood vessels.  

PubMed

The technique of magnetic drug targeting deals with binding drugs or genetic material to superparamagnetic nanoparticles and accumulating these complexes via an external magnetic field in a target region. For a successful approach, it is necessary to know the required magnetic setup as well as the physical properties of the complexes. With the help of computational methods, the complex accumulation and behavior can be predicted. We present a model for vascular targeting with a full three-dimensional analysis of the magnetic and fluidic forces and a subsequent evaluation of the resulting trajectories of the complexes. These trajectories were calculated with respect to the physiological boundary conditions, the magnetic properties of both the external field and the particles as well as the hydrodynamics of the fluid. We paid special regard to modeling input parameters like flow velocity as well as the distribution functions of the hydrodynamic size and magnetic moment of the nanoparticle complexes. We are able to estimate the amount of complexes, as well as the spatial distribution of those complexes. Additionally, we examine the development of the trapping rate for multiple passages of the complexes and compare the influence of several input parameters. Finally, we provide experimental data of an ex vivo flow-loop system which serves as a model for large vessel targeting. In this model, we achieve a deposition of lentivirus/magnetic nanoparticle complexes in a murine aorta and compare our simulation with the experimental results gained by a non-heme-iron assay. PMID:22663555

Heidsieck, Alexandra; Vosen, Sarah; Zimmermann, Katrin; Wenzel, Daniela; Gleich, Bernhard

2012-07-01

366

European Journal of Mechanics A/Solids 24 (2005) 2333 A one-dimensional model for blood flow in prestressed vessels  

E-print Network

waveforms entering the vessel and avoiding spurious reflections. 2005 Elsevier SAS. All rights reserved-7538/$ ­ see front matter 2005 Elsevier SAS. All rights reserved. doi:10.1016/j.euromechsol.2004.10.002 #12European Journal of Mechanics A/Solids 24 (2005) 23­33 A one-dimensional model for blood flow

Pontrelli, Giuseppe

367

A dynamic model of neurovascular coupling: implications for blood vessel dilation and constriction  

PubMed Central

Neurovascular coupling in response to stimulation of the rat barrel cortex was investigated using concurrent multichannel electrophysiology and laser Doppler flowmetry. The data was used to build a linear dynamic model relating neural activity to blood flow. Local field potential time series were subject to current source density analysis, and the time series of a layer IV sink of the barrel cortex was used as the input to the model. The model output was the time series of the changes in regional cerebral blood flow (CBF). We show that this model can provide excellent fit of the CBF responses for stimulus durations of up to 16s. The structure of the model consisted of two coupled components representing vascular dilation and constriction. The complex temporal characteristics of the CBF time series was reproduced by the relatively simple balance of these two components. We show that the impulse response obtained under the 16s duration stimulation condition generalised to provide a good prediction to the data from the shorter duration stimulation conditions. Furthermore by optimising three out of the total of nine model parameters, the variability in the data can be well accounted for over a wide range of stimulus conditions. By establishing linearity, classic system analysis methods can be used to generate and explore a range of equivalent model structures (e.g. feed-forward or feedback) to guide the experimental investigation of the control of vascular dilation and constriction following stimulation. PMID:20138217

Zheng, Ying; Pan, Yi; Harris, Sam; Billings, Steve; Coca, Daniel; Berwick, Jason; Jones, Myles; Kennerley, Aneurin; Johnston, David; Martin, Chris; Devonshire, Ian M.; Mayhew, John

2010-01-01

368

A three-dimensional atlas of human dermal leukocytes, lymphatics, and blood vessels.  

PubMed

Dendritic cells (DCs), macrophages (M?), and T cells are major components of the skin immune system, but their interstitial spatial organization is poorly characterized. Using four-channel whole-mount immunofluorescence staining of the human dermis, we demonstrated the three-dimensional distribution of CD31(+) blood capillaries, LYVE-1(+) lymphatics, discrete populations of CD11c(+) myeloid DCs, FXIIIa(+) M?, and lymphocytes. We showed phenotypic and morphological differences in situ between DCs and M?. DCs formed the first dermal cellular layer (0-20 ?m beneath the dermoepidermal junction), M? were located deeper (40-60 ?m), and CD3(+) lymphocytes were observed throughout (0-60 ?m). Below this level, DCs, T cells, and the majority of M? formed stable perivascular sheaths. Whole-mount imaging revealed the true extent of dermal leukocytes previously underestimated from cross-section views. The total area of apical dermis (0-30 ?m) contained approximately 10-fold more myeloid DCs than the entire blood volume of an average individual. Surprisingly, <1% of dermal DCs occupied lymphatics in freshly isolated skin. Dermal DCs rapidly accumulated within lymphatics, but M? remained fixed in skin explants cultured ex vivo. The leukocyte architecture observed in normal skin was distorted in inflammation and disease. These studies illustrate the micro-anatomy of dermal leukocytes and provide further insights into their functional organization. PMID:24352044

Wang, Xiao-Nong; McGovern, Naomi; Gunawan, Merry; Richardson, Connor; Windebank, Martin; Siah, Tee-Wei; Lim, Hwee-Ying; Fink, Katja; Li, Jackson L Yao; Ng, Lai G; Ginhoux, Florent; Angeli, Veronique; Collin, Matthew; Haniffa, Muzlifah

2014-04-01

369

Functional photoacoustic micro-imaging of cerebral hemodynamic changes in single blood vessels after photo-induced brain stroke  

NASA Astrophysics Data System (ADS)

Studying the functional hemodynamic roles of individual cerebral cortical arterioles in maintaining both the structure and function of cortical regions during and after brain stroke in small animals is an important issue. Recently, functional photoacoustic microscopy (fPAM) has been proved as a reliable imaging technique to probe the total hemoglobin concentration (HbT), cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) in single cerebral blood vessels of rats. Here, we report the application of fPAM associated with electrophysiology recordings to investigating functional hemodynamic changes in single cortical arterioles of rats with electrical forepaw stimulation after photo-induced ischemic stroke. Because of the weak optical focusing nature of our fPAM system, photo-induced ischemic stroke targeting single cortical arterioles can be easily conducted with simple adaptation. Functional HbT, CBV and SO2 changes associated with the induced stroke in selected arterioles from the anterior cerebral artery system were imaged with 36 x 65-?m spatial resolution. Experimental results showed that after photo-occlusion of a single arteriole, the functional changes of nearby arterioles in cerebral cortex only can be observed immediately after the stroke. After a few minutes of stroke onset, there are no significant functional changes under the forepaw stimulation, suggesting that alternate blood flow routes are not actively recruited. The fPAM with electrophysiology recordings complements existing imaging techniques and has the potential to offer a favorable tool for explicitly studying cerebral hemodynamics in small animal models of photo-indcued ischemic stroke.

Liao, Lun-De; Chen, You-Yin; Lin, Chin-Teng; Li, Meng-Lin

2013-03-01

370

An in vitro study of magnetic particle targeting in small blood vessels  

NASA Astrophysics Data System (ADS)

The magnetic guidance and capture of particles inside the human body, via the circulatory system, is a novel method for the targeted delivery of drugs. This experimental study confirms in vitro that a dipolar capturing device, based on high-energy magnets with an active space of 8.7 cm 10 cm 10 cm, retains colloidal magnetic particles (MPs) (<30 nm) injected in the capillary tubes, where flow velocities are comparable to that encountered in the capillary beds of tumours (<0.5 cm s-1). The build-up of the deposition of the MPs was investigated using video imaging techniques that enabled continuous monitoring of the blocking of the vessel whilst simultaneously recording the colloid's flow rate. The parameters of practical importance (length of MP deposit, time of capillary blocking) were estimated and were found to be dependent on the initial fluid velocity, the MP concentration and the distance between the capillary tube and the polar magnetic pieces. Although the tube used in this experiment is larger (diameter = 0.75 mm, length = 100 mm) than that of real capillaries (diameter = 0.01 mm, length ~1.5 mm), the flow velocities chosen were similar to those encountered in the capillary beds of tumours and the length/diameter ratio was approximately equal (133 for the present set-up, 100-150 for real capillaries). In these circumstances and using the same magnetic field conditions (intensity, gradient) and MPs, there is close similarity with magnetic capture in a microscopic capillary system. Moreover, the macroscopic system permits analysis of the distribution of MPs in the active magnetic space, and consequently the maximum targetable volume. This study revealed that the capture of particles within the active space was strongly influenced by the gradient of the magnetic field and the flow velocity. Thus, when the magnetic field gradient had medium values (0.1-0.3 T cm-1) and the fluid velocity was small (0.15 cm s-1), the particles were captured in small, compact and stable deposits (L < 4 cm) and the time necessary for blocking of the capillary was <150 s. Doubling the value for the flow velocity did not influence significantly either the length of MP deposits nor the blocking time. However, lower gradients (<0.1 T cm-1) and larger velocities (0.3-0.9 cm s-1) result in the formation of larger deposits (4 cm < L < 10 cm) that are unstable at the beginning of the capture process. These large deposits do become stable given sufficient time for the deposition process to take place in conjunction with a decrease in the flow rate. As a consequence, the time necessary for blocking of the capillary increased up to 450 s. Decreasing the MP concentration from 0.02 g cm-3 to 0.005 g cm-3 decreased the deposit lengths by approximately 20% and doubled the values of the blocking time. The maximum targetable volume obtained by the present method is ~350 cm3, which corresponds to medium-sized tumours. The capillary vessels were blocked only for the situation that occurs for microcirculation within a tumour. This reduces the concentration of MPs trapped within the normal tissues, which occurs when using particles of micrometre size. This work showed the potential of using colloidal MPs and dipolar magnetic devices for treatment of human patients, when the affected sites are positioned at medium distances from the surface of the body (e.g. head, neck, breast, hands and legs).

Udrea, Laura Elena; Strachan, Norval J. C.; B?descu, Vasile; Rotariu, Ovidiu

2006-10-01

371

An in vitro study of magnetic particle targeting in small blood vessels.  

PubMed

The magnetic guidance and capture of particles inside the human body, via the circulatory system, is a novel method for the targeted delivery of drugs. This experimental study confirms in vitro that a dipolar capturing device, based on high-energy magnets with an active space of 8.7 cm x 10 cm x 10 cm, retains colloidal magnetic particles (MPs) (<30 nm) injected in the capillary tubes, where flow velocities are comparable to that encountered in the capillary beds of tumours (<0.5 cm s(-1)). The build-up of the deposition of the MPs was investigated using video imaging techniques that enabled continuous monitoring of the blocking of the vessel whilst simultaneously recording the colloid's flow rate. The parameters of practical importance (length of MP deposit, time of capillary blocking) were estimated and were found to be dependent on the initial fluid velocity, the MP concentration and the distance between the capillary tube and the polar magnetic pieces. Although the tube used in this experiment is larger (diameter = 0.75 mm, length = 100 mm) than that of real capillaries (diameter = 0.01 mm, length approximately 1.5 mm), the flow velocities chosen were similar to those encountered in the capillary beds of tumours and the length/diameter ratio was approximately equal (133 for the present set-up, 100-150 for real capillaries). In these circumstances and using the same magnetic field conditions (intensity, gradient) and MPs, there is close similarity with magnetic capture in a microscopic capillary system. Moreover, the macroscopic system permits analysis of the distribution of MPs in the active magnetic space, and consequently the maximum targetable volume. This study revealed that the capture of particles within the active space was strongly influenced by the gradient of the magnetic field and the flow velocity. Thus, when the magnetic field gradient had medium values (0.1-0.3 T cm(-1)) and the fluid velocity was small (0.15 cm s(-1)), the particles were captured in small, compact and stable deposits (L < 4 cm) and the time necessary for blocking of the capillary was <150 s. Doubling the value for the flow velocity did not influence significantly either the length of MP deposits nor the blocking time. However, lower gradients (<0.1 T cm(-1)) and larger velocities (0.3-0.9 cm s(-1)) result in the formation of larger deposits (4 cm < L < 10 cm) that are unstable at the beginning of the capture process. These large deposits do become stable given sufficient time for the deposition process to take place in conjunction with a decrease in the flow rate. As a consequence, the time necessary for blocking of the capillary increased up to 450 s. Decreasing the MP concentration from 0.02 g cm(-3) to 0.005 g cm(-3) decreased the deposit lengths by approximately 20% and doubled the values of the blocking time. The maximum targetable volume obtained by the present method is approximately 350 cm(3), which corresponds to medium-sized tumours. The capillary vessels were blocked only for the situation that occurs for microcirculation within a tumour. This reduces the concentration of MPs trapped within the normal tissues, which occurs when using particles of micrometre size. This work showed the potential of using colloidal MPs and dipolar magnetic devices for treatment of human patients, when the affected sites are positioned at medium distances from the surface of the body (e.g. head, neck, breast, hands and legs). PMID:16985276

Udrea, Laura Elena; Strachan, Norval J C; B?descu, Vasile; Rotariu, Ovidiu

2006-10-01

372

Lytic and mechanical stability of clots composed of fibrin and blood vessel wall components  

PubMed Central

Background Proteases expressed in atherosclerotic plaque lesions generate collagen fragments, release glycosaminoglycans (chondroitin sulfate [CS] and dermatan sulfate [DS]) and expose extracellular matrix (ECM) proteins (e.g. decorin) at sites of fibrin formation. Objective Here we address the effect of these vessel wall components on the lysis of fibrin by the tissue plasminogen activator (tPA)/plasminogen system and on the mechanical stability of clots. Methods and results MMP-8-digested collagen fragments, isolated CS, DS, glycosylated decorin and its core protein were used to prepare mixed matrices with fibrin (additives present at a 50-fold lower mass concentration than fibrinogen). Scanning electron microscopy (SEM) showed that the presence of ECM components resulted in a coarse fibrin structure, most pronounced for glycosylated decorin causing an increase in the median fiber diameter from 85 to 187 nm. Rheological measurements indicated that these structural alterations were coupled to decreased shear resistance (1.8-fold lower shear stress needed for gel/fluid transition of the clots containing glycosylated decorin) and rigidity (reduction of the storage modulus from 54.3 to 33.2 Pa). The lytic susceptibility of the modified fibrin structures was increased. The time to 50% lysis by plasmin was reduced approximately 2-fold for all investigated ECM components (apart from the core protein of decorin which produced a moderate reduction of the lysis time by 25%), whereas fibrin-dependent plasminogen activation by tPA was inhibited by up to 30%. Conclusion ECM components compromise the chemical and mechanical stability of fibrin as a result of changes in its ultrastructure. PMID:23279194

Rottenberger, Z; Komorowicz, E; Szab, L; Bta, A; Varga, Z; Machovich, R; Longstaff, C; Kolev, K

2013-01-01

373

Blood (For Parents)  

MedlinePLUS

... about the mysterious, life-sustaining fluid called blood. Blood Basics Two types of blood vessels carry blood ... mixture of blood cells and plasma. Continue Red Blood Cells Red blood cells (also called erythrocytes) are ...

374

Endothelial podosome rosettes regulate vascular branching in tumour angiogenesis.  

PubMed

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

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

375

Placental mesenchymal stromal cells derived from blood vessels or avascular tissues: what is the better choice to support endothelial cell function?  

PubMed

Mesenchymal stromal cells (MSCs) are promising tools for therapeutic revascularization of ischemic tissues and for support of vessel formation in engineered tissue constructs. Recently, we could show that avascular-derived MSCs from placental amnion release soluble factors that exhibit survival-enhancing effects on endothelial cells (ECs). We hypothesize that MSCs derived from placental blood vessels might have even more potent angiogenic effects. Therefore, we isolated and characterized MSCs from placental chorionic blood vessels (bv-MSCs) and tested their angiogenic potential in comparison to amnion-derived avascular MSCs (av-MSCs). bv-MSCs express a very similar surface marker profile compared with av-MSCs and could be differentiated toward the adipogenic and osteogenic lineages. bv-MSCs exert immunosuppressive properties on peripheral blood mononuclear cells, suggesting that they are suitable for cell transplantation settings. Conditioned medium (Cdm) from av-MSCs and bv-MSCs significantly enhanced EC viability, whereas only Cdm from bv-MSCs significantly increased EC migration and network formation (Matrigel assay). Angiogenesis array analysis of av- and bv-MSC-Cdm revealed a similar secretion pattern of angiogenic factors, including angiogenin, interleukins-6 and -8, and tissue inhibitors of matrix metalloproteinase-1 and 2. Enzyme-linked immunosorbent assay analysis showed that, in contrast to av-MSCs, bv-MSCs secreted vascular endothelial growth factor. In direct coculture with bv-MSCs, ECs showed a significantly increased formation of vessel-like structures compared with av-MSCs. With regard to therapeutic treatment, bv-MSCs and particularly their Cdm might be valuable to stimulate angiogenesis especially in ischemic tissues. av-MSCs and their Cdm could be beneficial in conditions when it is required to promote the survival and stabilization of blood vessels without the risk of unmeant angiogenesis. PMID:25244528

Knig, Julia; Weiss, Gregor; Rossi, Daniele; Wankhammer, Karin; Reinisch, Andreas; Kinzer, Manuela; Huppertz, Berthold; Pfeiffer, Dagmar; Parolini, Ornella; Lang, Ingrid

2015-01-01

376

Placental Mesenchymal Stromal Cells Derived from Blood Vessels or Avascular Tissues: What Is the Better Choice to Support Endothelial Cell Function?  

PubMed Central

Mesenchymal stromal cells (MSCs) are promising tools for therapeutic revascularization of ischemic tissues and for support of vessel formation in engineered tissue constructs. Recently, we could show that avascular-derived MSCs from placental amnion release soluble factors that exhibit survival-enhancing effects on endothelial cells (ECs). We hypothesize that MSCs derived from placental blood vessels might have even more potent angiogenic effects. Therefore, we isolated and characterized MSCs from placental chorionic blood vessels (bv-MSCs) and tested their angiogenic potential in comparison to amnion-derived avascular MSCs (av-MSCs). bv-MSCs express a very similar surface marker profile compared with av-MSCs and could be differentiated toward the adipogenic and osteogenic lineages. bv-MSCs exert immunosuppressive properties on peripheral blood mononuclear cells, suggesting that they are suitable for cell transplantation settings. Conditioned medium (Cdm) from av-MSCs and bv-MSCs significantly enhanced EC viability, whereas only Cdm from bv-MSCs significantly increased EC migration and network formation (Matrigel assay). Angiogenesis array analysis of av- and bv-MSC-Cdm revealed a similar secretion pattern of angiogenic factors, including angiogenin, interleukins-6 and -8, and tissue inhibitors of matrix metalloproteinase-1 and 2. Enzyme-linked immunosorbent assay analysis showed that, in contrast to av-MSCs, bv-MSCs secreted vascular endothelial growth factor. In direct coculture with bv-MSCs, ECs showed a significantly increased formation of vessel-like structures compared with av-MSCs. With regard to therapeutic treatment, bv-MSCs and particularly their Cdm might be valuable to stimulate angiogenesis especially in ischemic tissues. av-MSCs and their Cdm could be beneficial in conditions when it is required to promote the survival and stabilization of blood vessels without the risk of unmeant angiogenesis. PMID:25244528

Knig, Julia; Weiss, Gregor; Rossi, Daniele; Wankhammer, Karin; Reinisch, Andreas; Kinzer, Manuela; Huppertz, Berthold; Pfeiffer, Dagmar; Parolini, Ornella

2015-01-01

377

Platelet lysate coating on scaffolds directly and indirectly enhances cell migration, improving bone and blood vessel formation.  

PubMed

Suitable colonization and vascularization of tissue-engineered constructs after transplantation represent critical steps for the success of bone repair. Human platelet lysate (hPL) is composed of numerous growth factors known for their proliferative, differentiative and chemo-attractant effects on various cells involved in wound healing and bone growth. The aim of this study was to determine whether the delivery of human mesenchymal stromal cells (hMSC) seeded on hPL-coated hydroxyapatite/?-tricalcium phosphate (HA/?-TCP) scaffolds could enhance vascularization and bone formation, as well as to investigate the mechanisms by which hMSC participate in tissue regeneration. Our study demonstrates that hPL can be coated on HA/?-TCP scaffolds, which play direct and indirect effects on implanted and/or resident stem cells. Effectively, we show that hPL coating directly increases chemo-attraction to and adhesion of hMSC and endothelial cells on the scaffold. Moreover, we show that hPL coating induces hMSC to produce and secrete pro-angiogenic proteins (placental growth factor and vascular endothelial growth factor) which allow the proliferation and specific chemo-attraction of endothelial cells in vitro, thus improving in vivo neovascularization and new bone formation. This study highlights the potential of functionalizing biomaterials with hPL and shows that this growth factor combination can have synergistic effects leading to enhanced bone and blood vessel formation. PMID:23403167

Leotot, Julie; Coquelin, Laura; Bodivit, Gwellaouen; Bierling, Philippe; Hernigou, Philippe; Rouard, Helene; Chevallier, Nathalie

2013-05-01

378

VEGF and angiopoietins promote inflammatory cell recruitment and mature blood vessel formation in murine sponge/Matrigel model.  

PubMed

A key feature in the induction of pathological angiogenesis is that inflammation precedes and accompanies the formation of neovessels as evidenced by increased vascular permeability and the recruitment of inflammatory cells. Previously, we and other groups have shown that selected growth factors, namely vascular endothelial growth factor (VEGF) and angiopoietins (Ang1 and Ang2) do not only promote angiogenesis, but can also induce inflammatory response. Herein, given a pro-inflammatory environment, we addressed the individual capacity of VEGF and angiopoietins to promote the formation of mature neovessels and to identify the different types of inflammatory cells accompanying the angiogenic process over time. Sterilized polyvinyl alcohol (PVA) sponges soaked in growth factor-depleted Matrigel mixed with PBS, VEGF, Ang1, or Ang2 (200?ng/200?l) were subcutaneously inserted into anesthetized mice. Sponges were removed at day 4, 7, 14, or 21 post-procedure for histological, immunohistological (IHC), and flow cytometry analyses. As compared to PBS-treated sponges, the three growth factors promoted the recruitment of inflammatory cells, mainly neutrophils and macrophages, and to a lesser extent, T- and B-cells. In addition, they were more potent and more rapid in the recruitment of endothelial cells (ECs) and in the formation and maturation (ensheating of smooth muscle cells around ECs) of neovessels. Thus, the autocrine/paracrine interaction among the different inflammatory cells in combination with VEGF, Ang1, or Ang2 provides a suitable microenvironment for the formation and maturation of blood vessels. PMID:25145474

Sinnathamby, Tharsika; Yun, JinTae; Clavet-Lanthier, Marie-laine; Cheong, Cheolho; Sirois, Martin G

2015-01-01

379

Blood  

MedlinePLUS

... mysterious, life-sustaining fluid called blood. What Is Blood and What Does It Do? Two types of ... mixture of blood cells and plasma. Continue Red Blood Cells Red blood cells (RBCs, and also called ...

380

Blood  

MedlinePLUS

... solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells deliver oxygen from your lungs to your tissues and organs. White blood cells fight infection and are part of your body's ...

381

[Effect of Shenlian extracts on blood flow and vessel pathological changes in rabbits carotid atherosclerosis model induced by low shear stress].  

PubMed

Lipid accumulation in the vessel wall and tunica intima vasorum pathological changes are important factors in the development of atherosclerosis, which are closely related with hemodynamics. In this paper, we established a model of local low shear stress in rabbits using carotid artery cannula and a high cholesterol diet for 2 weeks, 4 weeks and 8 weeks. The effects of Shenlian extract on blood flow, vascular pathology formation and lipid metabolism were assessed by electromagnetic blood flow meter and hematoxylin-eosin staining of the proximal end in carotid artery at different times. The results demonstrate that the relationship between blood flow and shear stress for control, atorvastatin, Shenlian extract high-dose, Shenlian extract middle-dose, and Shenlian extract low-dose were linearly related. The blood flow and the shear stress of proximal end in carotid artery of Shenlian extract (1.12, 2.24, 4.48 g x kg(-1)), and atorvastatin (4.7 x 10(-4) g x kg(-1)) were significantly (P < 0.05)increased compared with the control. Plasma total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) ,and high density lipoprotein cholesterol (HDL-C) were markedly decreased with the increasing of dose and time. This study is the first to prove that the inhibition of Shenlian extract on low shear stress (LSS) induces rabbits carotid atherosclerosis with increasing blood flow and decreasing lipids and vessel pathological changes. PMID:23947145

Zhou, Shu-Yuan; Wang, Ying-Han; Li, Yu-Jie; Yang, Qing; Gong, Zi-Peng; Ruan, Cong-Xiao; Kan, Xiao-Xi; Zhang, Rui-Jie; Zhu, Xiao-Xin

2013-05-01

382

Effect of Avastin on the number and structure of tumor blood vessels of nude mice with A549 lung adenocarcinoma  

PubMed Central

The aim of the present study was to investigate the effect of Avastin on the number and structure of tumor blood vessels of nude mice with A549 lung adenocarcinoma. A total of 30 nude mice were randomly divided into three groups, namely the control, the Avastin I (Avastin 3 mg/kg) and the Avastin II (Avastin 6 mg/kg) groups. Following treatment, ELISA was used to detect the expression level of vascular endothelial growth factor (VEGF) in tumor tissues. The microvascular density in tumor tissues and tumor vascular pericyte coverage was detected by immunofluorescence. The tumor growth and survival rate of mice in the three groups were also analyzed. Compared with the control group, the Avastin I and II groups exhibited significantly decreased VEGF levels and microvascular density in the tumor tissues, with the decrease in the Avastin II group being more prominent (P<0.05). After 7 days of treatment, the vascular pericyte coverage in the tumor tissues of mice in the Avastin I and II groups was significantly increased compared with that in the control group mice (P<0.05). Compared with the control group, the mice in the Avastin I and II groups exhibited a significantly decreased tumor growth rate and this effect was dose-dependent. The survival rate of mice in the Avastin I and II groups was significantly increased compared with that of the mice in the control group (P<0.05). In conclusion, Avastin significantly decreased the microvascular density of the tumor in nude mice with A549 lung adenocarcinoma and also significantly increased tumor vascular pericyte coverage, inhibited tumor growth and increased the survival rate of the mice, through its potent antiangiogenic activity. PMID:25371722

ZHANG, NALI; ZHANG, GUOJUN; ZHENG, YOUGUANG; WANG, TONGBING; WANG, HONGLEI

2014-01-01

383

Vasodilatory effects of homologous adrenomedullin 2 and adrenomedullin 5 on isolated blood vessels of two species of eel.  

PubMed

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

Cameron, Melissa S; Nobata, Shigenori; Takei, Yoshio; Donald, John A

2015-01-01

384

Nerve and Blood Vessels  

Microsoft Academic Search

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated\\u000a and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based\\u000a on the fascicular

Maura Valle; Maria Pia Zamorani

385

The absorbed dose to blood from blood-borne activity.  

PubMed

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)?Gys(-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 1.1-1.210(-11)?Gys(-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 -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. PMID:25559247

Hnscheid, H; Fernndez, M; Lassmann, M

2015-01-21

386

The absorbed dose to blood from blood-borne activity  

NASA Astrophysics Data System (ADS)

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?Gys?1Bq?1ml) 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 1.11.210?11?Gys?1Bq?1ml to the total dose rate for positron emitters but significantly less for the other nuclides. Blood self-absorption of the energy emitted by -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.

Hnscheid, H.; Fernndez, M.; Lassmann, M.

2015-01-01

387

A mathematical model of Bloch NMR equations for quantitative analysis of blood flow in blood vessels of changing cross-section-PART II  

NASA Astrophysics Data System (ADS)

Unlike most medical imaging modalities, magnetic resonance imaging (MRI) is based on effects that cross multiple biological levels: contrast depends on interactions between the local chemistry, water mobility, microscopic magnetic environment at the subcellular, cellular or vascular level, cellular integrity, etc. These interactions potentially allow for imaging functional changes in the same reference frame as the anatomic information. However, to tap this potential, we need methodologies that robustly incorporate the best models of the underlying physics interactions in order to extract the best possible interaction obtainable on flow velocity and rates. Due to the fundamental role the Bloch NMR equations play in the analysis of the properties of magnetic resonance imaging, this presentation will focus on mathematical modeling of the Bloch NMR flow equations into the harmonic differential equation. This simplification allows us to explain qualitatively, the effects of coriolis force on the motion of flowing fluid. The Transverse magnetization My, is introduced as a stream function. Our choice of conditions has led to a linear equation for My. We derived the stream function as a form of solution which contains the linearity property demanded by conditions at x=0. The resulting flow reveals some interesting wave-like properties which were examined directly. The existence of the waves is associated with the non-uniformity of the Coriolis parameter, and it is not difficult to see the general mechanism. The quantum mechanical models of Bloch NMR equations describe dynamical states of particles in flowing fluid. We introduce the basic background for understanding some of the applications of quantum mechanics to NMR and explain their significance and potentials. It also describes the behavior of the rF B1 field when the fluid particles flow under physiological and some modeled pathological conditions. The wave function is explored to determine the minimum energy, a function of the rF B1 field for the fluid particle to be located in the non-classical region. These models can be invaluable to understand the basic Physics of extracting the relevant flow parameters by which velocity quantification can be made in Blood vessels with changing cross-section.

Awojoyogbe, O. B.

2003-05-01

388

Specific Accumulation of Tumor-Derived Adhesion Factor in Tumor Blood Vessels and in Capillary Tube-Like Structures of Cultured Vascular Endothelial Cells  

NASA Astrophysics Data System (ADS)

Tumor-derived adhesion factor (TAF) was previously identified as a cell adhesion molecule secreted by human bladder carcinoma cell line EJ-1. To elucidate the physiological function of TAF, we examined its distribution in human normal and tumor tissues. Immunochemical staining with an anti-TAF monoclonal antibody showed that TAF was specifically accumulated in small blood vessels and capillaries within and adjacent to tumor nests, but not in those in normal tissues. Tumor blood vessel-specific staining of TAF was observed in various human cancers, such as esophagus, brain, lung, and stomach cancers. Double immunofluorescent staining showed apparent colocalization of TAF and type IV collagen in the vascular basement membrane. In vitro experiments demonstrated that TAF preferentially bound to type IV collagen among various extracellular matrix components tested. In cell culture experiments, TAF promoted adhesion of human umbilical vein endothelial cells to type IV collagen substrate and induced their morphological change. Furthermore, when the endothelial cells were induced to form capillary tube-like structures by type I collagen, TAF and type IV collagen were exclusively detected on the tubular structures. The capillary tube formation in vitro was prevented by heparin, which inhibited the binding of TAF to the endothelial cells. These results strongly suggest that TAF contributes to the organization of new capillary vessels in tumor tissues by modulating the interaction of endothelial cells with type IV collagen.

Akaogi, Kotaro; Okabe, Yukie; Sato, Junji; Nagashima, Yoji; Yasumitsu, Hidetaro; Sugahara, Kazuyuki; Miyazaki, Kaoru

1996-08-01

389

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

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

Yu, Haibo; Chen, Pengdian; Yang, Zhuoxin; Luo, Wenshu; Pi, Min; Wu, Yonggang; Wang, Ling

2014-01-01

390

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)

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.

Philpott, D. E.; Harrison, G.; Turnbill, C.; Bailey, P. F.

1979-01-01

391

Relationship between the distribution of the paired-like homeobox gene (Phox2b) expressing cells and blood vessels in the parafacial region of the ventral medulla of neonatal rats.  

PubMed

It has been reported that central chemoreceptor cells in the medulla are distributed in close apposition to capillary blood vessels in the medulla. Phox2b-expressing neurons in the retrotrapezoid nucleus (RTN) respond to high CO(2)/H(+) stimulation and have been suggested to play an important role in central chemoreception. In newborn rats, the RTN overlaps at least partially with the parafacial respiratory group (pFRG), which consists predominantly of preinspiratory neurons. In the present study, we visualized the blood vessels in the ventral medulla of newborn rats using a neurobiotin method and examined the relationship between the blood vessels and the location of Phox2b-immunoreactive (-ir) neurons. We showed that Phox2b-ir neurons in the parafacial region of the rostral ventral medulla tended to assemble around capillary blood vessels. We also confirmed that pFRG/preinspiratory neurons that were sensitive to hypercapnic stimulation in the presence of tetrodotoxin were Phox2b-ir neurons and were tightly apposed to the blood vessels along the longitudinal axis. Our findings suggested that the location of Phox2b-ir neurons, including preinspiratory neurons of the pFRG, matched their role as sensors of blood CO(2) concentration. PMID:22521817

Onimaru, H; Ikeda, K; Kawakami, K

2012-06-14

392

Assessment of implanted stent coverage of side-branches in intravascular optical coherence tomographic images  

NASA Astrophysics Data System (ADS)

Coronary stents improve the blood flow by keeping narrowed vessels open, but small stent cells that overlay a side branch may cause restenosis and obstruct the blood flow to the side branch. There are increasing demands for precise measurement of the stent coverage of side branches for outcome evaluation and clinical research. Capturing micrometerresolution images, intravascular optical coherence tomography (IVOCT) allows proper visualization of the stent struts, which subsequently can be used for the coverage measurement purpose. In this paper, a new approach to compute the stent coverage of side branches in IVOCT image sequences is presented. The amount of the stent coverage of a side branch is determined by the ostial area of the stent cells that cover this side branch. First, the stent struts and the guide wires are detected to reconstruct the irregular stent surface and the stent cell contours are generated to segment their coverage area on the stent surface. Next, the covered side branches are detected and their lumen contours are projected onto the stent surface to specify the side branch areas. By assessing the common parts between the stent cell areas and the side branch areas, the stent cell coverage of side branches can be computed. The evaluation based on a phantom data set demonstrated that the average error of the stent coverage of side branches is 8.9% +/- 7.0%. The utility of the presented approach for in-vivo data sets was also proved by the testing on 12 clinical IVOCT image sequences.

Wang, A.; Eggermont, J.; Reiber, J. H. C.; Dekker, N.; de Koning, P. J. H.; Dijkstra, J.

2013-02-01

393

Fibronectins Are Essential for Heart and Blood Vessel Morphogenesis But Are Dispensable for Initial Specification of Precursor Cells  

Microsoft Academic Search

The underlying mechanisms of lethal cardiovascular defects are distended and lack contact with the surrounding mesen- associated with the fibronectin-null (FN.null) mutation in chyme, while no vessels form in the yolk sac. Defects in the mouse embryos were investigated by lineage analysis of more severe class suggest that FNs are essential earlier in myocardial, endocardial, and endothelial cells. A wide

Elizabeth L. George; H. Scott Baldwin; Richard O. Hynes

1997-01-01

394

A robust and accurate approach to automatic Blood Vessel detection and segmentation from Angiography X-ray images  

E-print Network

stages: seed selection, DVI(Directional Vector Integration) based fiber growing, centerline extraction consisting of positive and negative examples of valid seed points. The method makes use of a 14 ? 14 window around a putative seed point. For this window three types of feature vectors are computed viz. vesselness

Kale, Amit

395

GFAP-Driven GFP Expression in Activated Mouse Mller Glial Cells Aligning Retinal Blood Vessels Following Intravitreal Injection of AAV2/6 Vectors  

PubMed Central

Background Mller cell gliosis occurs in various retinal pathologies regardless of the underlying cellular defect. Because activated Mller 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 Mller glial cells aligning the retinal blood vessels. However, the transduction capacity was hindered by the inner limiting membrane (ILM) and besides Mller glial cells, several other inner retinal cell types were transduced. To obtain Mller 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 Mller 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

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

396

The Use of Fractal Dimension Analysis in Estimation of Blood Vessels Shape in Transplantable Mammary Adenocarcinoma in Wistar Rats after Photodynamic Therapy Combined with Cysteine Protease Inhibitors  

PubMed Central

Fractal dimension analysis (FDA) is modern mathematical method widely used to describing of complex and chaotic shapes when classic methods fail. The main aim of this study was evaluating the influence of photodynamic therapy (PDT) with cystein proteases inhibitors (CPI) on the number and morphology of blood vessels inside tumor and on increase of effectiveness of combined therapy in contrast to PDT and CPI used separately. Animals were divided into four groups: control, treated using only PDT, treated using only CPI and treated using combined therapy, PDT and CPI. Results showed that time of animal survival and depth of necrosis inside tumor were significantly higher in CPI+PDT group in contrast to other groups. The higher value of fractal dimension (FD) was observed in control group, while the lowest value was found in the group which was treated by cystein protease inhibitors. The differences between FD were observed in CPI group and PDT+CPI group in comparison to control group. Our results revealed that fractal dimension analysis is a very useful tool in estimating differences between irregular shapes like blood vessels in PDT treated tumors. Thus, the implementation of FDA algorithms could be useful method in evaluating the efficacy of PDT. PMID:22991578

Jurczyszyn, Kamil; Osiecka, Beata J.; Zi?kowski, Piotr

2012-01-01

397

Rapid onset of perfused blood vessels after implantation of ECFCs and MPCs in collagen, PuraMatrix and fibrin provisional matrices.  

PubMed

We developed an in vivo vascularization model in which human endothelial colony-forming cells (ECFCs) and human mesenchymal progenitor cells (MPCs) form blood vessel networks when co-injected (ECFC?+?MPC) into nude mice in rat tail type I collagen, bovine fibrin or synthetic peptide PuraMatrix matrices. We used three approaches to determine the onset of functional vascularization when ECFC?+?MPC suspended in these matrices were implanted in vivo. The first was immunohistochemistry to detect vessels lined by human endothelial cells and filled with red blood cells. The second was in vivo vascular staining by tail vein injection of a mixture of Ulex europaeus agglutinin I (UEA-I), a lectin specific for human endothelium, and Griffonia simplicifolia isolectin B4 (GS-IB4 ), a lectin specific for rodent endothelium. The third approach employed contrast-enhanced ultrasound to measure the perfusion volumes of implants in individual animals over time. Human endothelial-lined tubular structures were detected in vivo on days 1 and 2 after implantation, with perfused human vessels detected on days 3 and 4. Contrast-enhanced ultrasound revealed significant perfusion of ECFC?+?MPC/collagen implants on days 1-4, at up to 14% perfused vascular volume. ECFC?+?MPC implanted in fibrin and PuraMatrix matrices also supported perfusion at day 1, as assessed by ultrasound (at 12% and 23% perfused vascular volume, respectively). This model demonstrates that ECFC?+?MPC suspended in any of the three matrices initiated a rapid onset of vascularization. We propose that ECFC?+?MPC delivered in vivo provide a means to achieve rapid perfusion of tissue-engineered organs or for in situ tissue repair. Copyright 2013 John Wiley & Sons, Ltd. PMID:23955835

Allen, Patrick; Kang, Kyu-Tae; Bischoff, Joyce

2013-08-16

398

Field confirmation of modified pressurized solvent extraction vessels for the analysis of polychlorinated biphenyl congeners in blood samples from Great Lakes Mallards (Anas platyrhynchos).  

PubMed

Miniaturized pressurized solvent extraction vessels were used to examine polychlorinated biphenyl congener (PCB) concentrations in 0.2 g sample sizes of whole blood, liver, heart and breast tissue sampled from twelve Great Lakes Mallard ducks (Anas platyrhynchos). This study successfully supported the blood extraction method, previously validated only using laboratory prepared blood samples, using field samples. In situ clean-up offered excellent sample throughput without degradation of GC-MS performance; using this method, extraction, instrument analysis and data interpretation for 100 samples could be accomplished within a one to two week time period. Results indicated contamination in the blood (?PCB = 1.9-13 ng g(-1) ww), liver (?PCB = 0.8-11 ng g(-1) ww), breast (?PCB = <0.1-9 ng g(-1) ww) and heart tissue (?PCB = <0.1-6 ng g(-1) ww). Quality control included the analysis of blank samples, NIST SRM 1589a and a duplicate of each sample type (blood or tissue). All blank samples were below the method detection limit, SRM values were within 70% of their certified values and duplicates were within 70% of each other. Correlations were examined for the suite of analysed congeners between blood and various tissues; within select individuals a strong and significant correlation was observed. TEQs were calculated and compared against known toxicity data for bird species. Based on the PCB levels found in this study, no adverse health effects are expected in the birds themselves. ?PCB concentrations in the breast tissue were also compared against both the Canadian and American guidelines for the consumption of edible poultry and based on these values, the Mallards used in this research would be safe for human consumption. PMID:23598430

Haskins, Stacey D; Kelly, David G; Weir, Ron D

2013-06-01

399

Identification of pro-angiogenic markers in blood vessels from stroked-affected brain tissue using laser-capture microdissection  

Microsoft Academic Search

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

Mark Slevin; Jerzy Krupinski; Norma Rovira; Marta Turu; Ana Luque; Maribel Baldellou; Coral Sanfeliu; Nuria de Vera; Lina Badimon

2009-01-01

400

Effect of Recombinant Human Epidermal Growth Factor Impregnated Chitosan Film on Hemostasis and Healing of Blood Vessels  

PubMed Central

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

Lee, Sangshin; Jung, Inwook; Yu, Seongcheol

2014-01-01

401

Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution  

PubMed Central

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

Qiu, Penghe; Mao, Chuanbin

2010-01-01

402

The effect of hypodynamia on the structure of the intraorganic blood vessels and the capacity of the blood stream in the diaphragm of white rats  

NASA Technical Reports Server (NTRS)

The effect of hypodynamia on the vascular system of white rats with diaphragm deprivation was investigated. Morphological changes in the intraorganic blood stream of the diaphragm were determined. The capacity of the intraorganic vascular flow within the diaphragm muscles was established.

Gerus, A. I.

1980-01-01

403

Vasoconstrictor responses to the P2x-purinoceptor agonist beta, gamma-methylene-L-ATP in human cutaneous and renal blood vessels.  

PubMed

1. Strips of human saphenous veins and of human renal arteries and veins were superfused with Krebs-Henseleit solution at 37 degrees C. Constrictor responses were elicited by exogenous noradrenaline and the P2x-purinoceptor-selective agonist, beta, gamma-methylene-L-ATP. 2. In human saphenous veins, beta, gamma-methylene-L-ATP (0.3-30 microM; EC50 2.2 microM) induced marked constrictor responses. The maximal response to beta, gamma-methylene-L-ATP was similar to the maximal response to noradrenaline. The P2-purinoceptor antagonist suramin (30 microM) shifted the concentration-response curve of beta, gamma-methylene-L-ATP to the right (apparent pKB value 4.8); suramin (100 microM) markedly inhibited the responses to beta, gamma-methylene-L-ATP. The preferential P2x-purinoceptor antagonist, pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; 3 microM) slightly reduced the response to beta, gamma-methylene-L-ATP. At a ten times higher concentration (30 microM), PPADS almost abolished the responses to beta, gamma-methylene-L-ATP. PPADS (30 microM), in contrast, caused no significant change in the concentration-response curve of noradrenaline. 3. In extrarenal and intrarenal arteries, EC50 values and maximal responses to noradrenaline were similar when compared with responses to noradrenaline in saphenous veins. Noradrenaline also constricted extrarenal veins. However, in contrast to the results obtained on saphenous veins, beta, gamma-methylene-L-ATP caused almost no constrictor responses in extrarenal veins and arteries and only moderate responses in intrarenal arteries. 4. The results demonstrate marked differe