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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

196 MATHEMATICS MAGAZINE Blood Vessel Branching: Beyond the  

E-print Network

). Cumulatively, this can modify the blood dynamics, as do the surface waves along the vessel walls, induced196 MATHEMATICS MAGAZINE Blood Vessel Branching: Beyond the Standard Calculus Problem JOHN A. ADAM arteries, veins, and capillaries that permit the flow of blood from the heart, around the body, and back

Adam, John A.

3

Ridge-branch-based blood vessel detection algorithm for multimodal retinal images  

Microsoft Academic Search

Automatic detection of retinal blood vessels is important to medical diagnoses and imaging. With the development of imaging technologies, various modals of retinal images are available. Few of currently published algorithms are applied to multimodal retinal images. Besides, the performance of algorithms with pathologies is expected to be improved. The purpose of this paper is to propose an automatic Ridge-Branch-Based

Y. Li; N. Hutchings; R. W. Knighton; G. Gregori; B. J. Lujan; J. G. Flanagan

2009-01-01

4

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 ...

Hirschi, Mrs.

2007-11-20

5

Centerline Computation and Geometric Analysis of Branching Tubular Surfaces with Application to Blood Vessel Modeling  

Microsoft Academic Search

In this work we present a robust and accurate method for the computation of centerlines inside branching tubular objects starting from a piecewise linear representation of their boundary. The algorithm is based on solving the Eikonal equation on the Voronoi diagram embedded into the object, with wavefront speed inversely proportional to Voronoi ball radius values. As a result, provably accurate

Luca Antiga; Bogdan Ene-iordache; Andrea Remuzzi

2003-01-01

6

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

7

Predicting Stenosis in Blood Vessels  

E-print Network

Predicting Stenosis in Blood Vessels Aneesh Bapat Advisors: Prof. Julie Young Dr. Craig Steeves Prof. Wole Soboyejo #12;Background The heart is a pump that sends oxygenated blood throughout the body) #12;Atherosclerosis Atherosclerosis is the hardening and narrowing of blood vessels caused by buildup

Petta, Jason

8

Tubulogenesis during blood vessel formation  

PubMed Central

The ability to form and maintain a functional system of contiguous hollow tubes is a critical feature of vascular endothelial cells (ECs). Lumen formation, or tubulogenesis, occurs in blood vessels during both vasculogenesis and angiogenesis in the embryo. Formation of vascular lumens takes place prior to the establishment of blood flow and to vascular remodeling which results in a characteristic hierarchical vessel organization. While epithelial lumen formation has received intense attention in past decades, more recent work has only just begun to elucidate the mechanisms controlling the initiation and morphogenesis of endothelial lumens. Studies using in vitro and in vivo models, including zebrafish and mammals, are beginning to paint an emerging picture of how blood vessels establish their characteristic morphology and become patent. In this chapter, we review and discuss the molecular and cellular mechanisms driving the formation of vascular tubes, primarily in vivo, and we compare and contrast proposed models for blood vessel lumen formation. PMID:21624487

Xu, Ke; Cleaver, Ondine

2011-01-01

9

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

10

Cuff for Blood-Vessel Pressure Measurements  

NASA Technical Reports Server (NTRS)

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

Shimizu, M.

1982-01-01

11

Disrupting tumour blood vessels  

Microsoft Academic Search

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

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

2005-01-01

12

BPC 157 and blood vessels.  

PubMed

This review focuses on the described effects of BPC 157 on blood vessels after different types of damage, and elucidate by investigating different aspects of vascular response to injury (endothelium damage, clotting, thrombosis, vasoconstriction, vasodilatation, vasculoneogenesis and edema formation) especially in connection to the healing processes. In this respect, BPC 157 was concluded to be the most potent angiomodulatory agent, acting through different vasoactive pathways and systems (e.g. NO, VEGF, FAK) and leading to optimization of the vascular response followed, as it has to be expected, by optimization of the healing process. Formation of new blood vessels involves two main, partly overlapping mechanisms, angiogenesis and vasculogenesis. The additional mechanism of arteriogenesis is involved in the formation of collaterals. In conjunction with blood vessel function, we at least have to consider leakage of fluid/proteins/plasma, resulting in edema/exudate formation as well as thrombogenesis. Blood vessels are also strongly involved in tumor biology. In this aspect, we have neoangiogenesis resulting in pathological vascularization, vascular invasion resulting in release of metastatic cells and the phenomenon of homing resulting in formation of secondary tumors--metastases. PMID:23782145

Seiwerth, Sven; Brcic, Luka; Vuletic, Lovorka Batelja; Kolenc, Danijela; Aralica, Gorana; Misic, Marija; Zenko, Anita; Drmic, Domagoj; Rucman, Rudolf; Sikiric, Predrag

2014-01-01

13

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

14

Smoking and Your Heart and Blood Vessels  

MedlinePLUS

... page from the NHLBI on Twitter. How Does Smoking Affect the Heart and Blood Vessels? Cigarette smoking ... Cough , discuss how smoking affects the lungs. Overview Smoking and Your Heart and Blood Vessels The chemicals ...

15

Blood Vessels of the Future  

NSDL National Science Digital Library

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

2011-06-03

16

Application of morphological bit planes in retinal blood vessel extraction.  

PubMed

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

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

2013-04-01

17

Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol  

E-print Network

that supplies the stomach, liver and spleen with blood. This is the celiac artery. c. Just below where the celiac branches off is the superior mesenteric, which supplies the small intestine. d. The left and right

Loughry, Jim

18

Dynamic mechanisms of blood vessel growth  

PubMed Central

The formation of a polygonal configuration of proto-blood-vessels from initially dispersed cells is the first step in the development of the circulatory system in vertebrates. This initial vascular network later expands to form new blood vessels, primarily via a sprouting mechanism. We review a range of recent results obtained with a Monte Carlo model of chemotactically migrating cells which can explain both de novo blood vessel growth and aspects of blood vessel sprouting. We propose that the initial network forms via a percolation-like instability depending on cell shape, or through an alternative contact-inhibition of motility mechanism which also reproduces aspects of sprouting blood vessel growth. PMID:19526066

Merks, Roeland M H; Glazier, James A

2009-01-01

19

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

20

Unsteady Flow in Stenotic Blood Vessels  

NASA Astrophysics Data System (ADS)

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

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

2003-11-01

21

Tianma modulates blood vessel tonicity.  

PubMed

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

22

Angiology: Diseases of the Blood Vessels  

Microsoft Academic Search

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

Gabriel A. Adelmann

23

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

24

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

25

The effects of blood vessels on electrocorticography  

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

26

HEART AND BLOOD VESSELS CARDIOVASCULARCARDIOVASCULAR  

E-print Network

the backward flow of blood due to gravity when closed. #12;THE HEARTTHE HEART · Located behind and slightly left of the breastbone(sternum) · Cone-shaped · Points slightly left · Has 4 chambers · 2 atria (sing a fibrous pericardium THE HEARTTHE HEART · Right and left atria empty into the right and left ventricles

Cochran-Stafira, D. Liane

27

Blood velocity measurement in human conjunctival vessels  

PubMed Central

The bulbar conjunctiva is one of the few areas in which blood flow in the peripheral vasculature can be directly and noninvasively observed in the human. Although extensive literature exists describing morphological changes which correlate with a variety of systemic diseases in this vasculature, little quantitative data is available on hemodynamics in either normal or abnormal states. The hemodynamic data available are primarily subjective assessments of “low flow.” Approaches to place the subjective assessment on more quantitative grounds have usually been based on photographic techniques that have intrinsic inadequacies. The objective of the work reported here was to develop a system capable of providing sequential blood velocity data potentially useful for providing quantitative information on blood flow and its change in the microvessels of the human conjunctiva. The method that has evolved uses a standard Zeiss slit-lamp to image a subject's conjunctival vessels by using a 1-inch Newvicon TV camera with an electronic magnification of 2x. The video image is simultaneously recorded on a video tape recorder (VTR) to an overall system magnification of approximately 4 ?m/raster line. The data acquisition phase requires approximately 5 minutes of patient time, whereas the actual determination of blood velocity in individual vessels is done offline through a modification of the dual-slit videodensimetric method. Two independently controllable video cursors are placed axially over the vessel image with the VTR in the still-frame mode. For each consecutive video field, the position of two reference points on the vessel and the position of each cursor relative to these and to each other are encoded into a computer to track the moving image caused by normal eye movement. The computer then determines new cursor coordinates to ensure a constant position within the vessel. The electrical signals obtained for each cursor site and for each video field are cross-correlated to yield the average blood velocity over the sampled time interval. The system has been calibrated in vitro from 0.2 to 2.5 mm/sec, evaluated in experimental animals, and used to measure blood velocity (0.3 to 1.5 mm/sec) in human conjunctival venules with diameters ranging from 20 to 50 ?m. At this writing, blood velocity has been recorded during a period of about 3 months in the same vessel of several postmyocardial infarction patients. Thus, the method appears suitable for determining sequential changes in small vessel blood flow in patients over extended periods of time. Images PMID:15216177

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

1981-01-01

28

Blackworms, Blood Vessel Pulsations and Drug Effects.  

ERIC Educational Resources Information Center

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

Lesiuk, Nalena M.; Drewes, Charles D.

1999-01-01

29

Automated measurement of retinal blood vessel tortuosity  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

30

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

31

Gene therapy method targets tumor blood vessels  

Cancer.gov

Working in mice, researchers at Washington University School of Medicine in St. Louis (home of the Alvin J. Siteman Cancer Center) report developing a gene delivery method long sought in the field of gene therapy: a deactivated virus carrying a gene of interest that can be injected into the bloodstream and make its way to the right cells. In this early proof-of-concept study, the scientists have shown that they can target tumor blood vessels in mice without affecting healthy tissues.

32

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-assisted detection and segmentation of blood vessels in angiography are crucial for endovascular treat- ments--Segmentation of Blood Vessels, Feature Detection, Statistical Segmentation, Active Contour Model, Angiography I

Chung, Albert C. S.

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

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

35

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

36

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

37

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

38

Blood vessel segmentation in magnetic resonance angiography imagery  

NASA Astrophysics Data System (ADS)

Small blood vessels may be difficult to detect in magnetic resonance angiography due to the lack of blood flow caused by disease or injury. Our method, which uses a block-matching denoising approach to segment blood vessels, works well in the presence of noise. We examined extended regions of an image to determine whether they contained blood vessels by fitting a Gaussian mixture model to a region's histogram. Then, dissimilar regions were denoised separately. This approach was beneficial in low-contrast settings. It can be used to detect higher-order blood vessels that may be difficult to detect under normal conditions.

Kozaitis, S. P.; Chandramohan, R.

2011-06-01

39

The blood vessel, linchpin of diabetic lesions.  

PubMed

The morbidity and mortality associated with diabetes mellitus are essentially related to the vascular lesions that develop over time in this condition. Both the macrocirculation and microcirculation are involved, and as a consequence, vital organs such as the brain, retina, heart, and kidney and the limbs become damaged. Because microalbuminuria represents the earliest and probably most sensitive indication of endothelial dysfunction in diabetes mellitus, the results of pharmacologic intervention with angiotensin-converting enzyme inhibitors, which treat glomerular hypertension were the first indication of potential beneficial effects in reducing diabetic nephroplasty. The nature of endothelial dysfunction related to diabetes is probably not homogeneous, since microcirculation networks are affected at different periods and with variable intensity. This appears to be the case for the aorta, the heart, segments of the digestive tract, the skin, and the skeletal muscle, the largest consumer of insulin. Although the aorta and large arteries contain a small portion of the total blood volume, their distribution of blood flow (pulse pressure) to peripheral organs may affect endothelial function in the microcirculation. Changes in the structure of conduit arteries, partly responsible for the alteration in compliance characteristics, could well be related to the way these arteries are fed by the vasa vasorum system. This report describes a new in vitro approach to examine capillary permeability in normal and alloxan-induced diabetic rabbits. Preliminary results indicate that the size of terminal arterioles of the vasa vasorum (increased diameter) and the capillary permeability to albumin (markedly enhanced) in this specialized network are profoundly affected in the thoracic aorta obtained from diabetic animals. Albumin extravasation into the interstitial fluid compartment of the aorta is likely to lead to structural and physicochemical changes: in fact, removal of interstitial macromolecules via lymphatic drainage is poor in the blood vessel wall of large arteries. This experimental approach is likely to be useful in the exploration of medications affecting the structure and function of conduit vessels. PMID:10094122

Plante, G E; Alfred, J; Chakir, M

1999-03-01

40

Photocoagulation of Dermal Blood Vessels With Multiple Laser Pulses in an In Vivo Microvascular Model  

PubMed Central

Background/Objectives Current laser therapy of port wine stain (PWS) birthmarks with a single laser pulse (SLP) does not produce complete lesion removal in the majority of patients. To improve PWS therapeutic efficacy, we evaluated the performance of an approach based on multiple laser pulses (MLP) to enhance blood vessel photocoagulation. Study Design The hamster dorsal window chamber model was used. Radiant exposure (RE), pulse repetition rate (fr), total number of pulses (np), and length of vessel irradiated were varied. Blood vessels in the window were irradiated with either SLP with RE of 4–7 J/cm2 or MLP with RE per pulse of 1.4–5.0 J/cm2, fr of 0.5–26.0 Hz, and np of 2–5. The laser wavelength was 532 nm and pulse duration was 1 ms. Either a 2 mm vessel segment or entire vessel branch was irradiated. Digital photographs and laser speckle images of the window were recorded before and at specific time points after laser irradiation to monitor laser-induced blood vessel structural and functional changes, respectively. Results We found that: (1) for a SLP approach, the RE required to induce blood vessel photocoagulation was 7 J/cm2 as compared to only 2 J/cm2 per pulse for the MLP approach; (2) for MLP, two pulses at a repetition rate of 5 Hz and a RE of 3 J/cm2 can induce photocoagulation of more than 80% of irradiated blood vessel; and (3) irradiation of a longer segment of blood vessel resulted in lower reperfusion rate. Conclusions The MLP approach can induce blood vessel photocoagulation at much lower RE per pulse as compared to SLP. The 5 Hz fr and the need for two pulses are achievable with modern laser technology, which makes the MLP approach practical in the clinical management of PWS birthmarks. PMID:22275290

Jia, Wangcun; Tran, Nadia; Sun, Victor; Marincek, Marko; Majaron, Boris; Choi, Bernard; Nelson, J. Stuart

2012-01-01

41

Extraction of exudates and blood vessels in digital fundus images  

Microsoft Academic Search

This paper proposes two efficient approaches for automatic detection and extraction of Exudates and Blood vessels in ocular fundus images. The blood vessel extraction algorithm is composed of three steps, i.e., matched filtering, thresholding and label filtering. The identification of exudates involves Preprocessing, Optic disk elimination, and Segmentation of Exudates. In both the methods the enhanced segments are extracted based

Giri Babu Kande; T. Satya Savithri; P. Venkata Subbaiah

2008-01-01

42

A model based method for retinal blood vessel detection  

Microsoft Academic Search

Retinal blood vessels are important structures in ophthalmological images. Many detection methods are available, but the results are not always satisfactory. In this paper, we present a novel model based method for blood vessel detection in retinal images. It is based on a Laplace and thresholding segmentation step, followed by a classi2cation step to improve performance. The last step assures

K. A. Vermeer; F. M. Vos; H. G. Lemij; A. M. Vossepoel

43

A model based method for retinal blood vessel detection  

Microsoft Academic Search

Retinal blood vessels are important structures in ophthalmological images. Many detection methods are available, but the results are not always satisfactory. In this paper, we present a novel model based method for blood vessel detection in retinal images. It is based on a Laplace and thresholding segmentation step, followed by a classification step to improve performance. The last step assures

K. A. Vermeer; F. M. Vos; H. G. Lemij; A. M. Vossepoel

2004-01-01

44

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

PubMed Central

Blood vessels form either when dispersed endothelial cells (the cells lining the inner walls of fully formed blood vessels) organize into a vessel network (vasculogenesis), or by sprouting or splitting of existing blood vessels (angiogenesis). Although they are closely related biologically, no current model explains both phenomena with a single biophysical mechanism. Most computational models describe sprouting at the level of the blood vessel, ignoring how cell behavior drives branch splitting during sprouting. We present a cell-based, Glazier–Graner–Hogeweg model (also called Cellular Potts Model) simulation of the initial patterning before the vascular cords form lumens, based on plausible behaviors of endothelial cells. The endothelial cells secrete a chemoattractant, which attracts other endothelial cells. As in the classic Keller–Segel model, chemotaxis by itself causes cells to aggregate into isolated clusters. However, including experimentally observed VE-cadherin–mediated contact inhibition of chemotaxis in the simulation causes randomly distributed cells to organize into networks and cell aggregates to sprout, reproducing aspects of both de novo and sprouting blood-vessel growth. We discuss two branching instabilities responsible for our results. Cells at the surfaces of cell clusters attempting to migrate to the centers of the clusters produce a buckling instability. In a model variant that eliminates the surface–normal force, a dissipative mechanism drives sprouting, with the secreted chemical acting both as a chemoattractant and as an inhibitor of pseudopod extension. Both mechanisms would also apply if force transmission through the extracellular matrix rather than chemical signaling mediated cell–cell interactions. The branching instabilities responsible for our results, which result from contact inhibition of chemotaxis, are both generic developmental mechanisms and interesting examples of unusual patterning instabilities. PMID:18802455

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

2008-01-01

45

Glucose metabolism in diabetic blood vessels  

SciTech Connect

Since glycolysis appears to be coupled to active ion transport in vascular smooth muscle, alterations in glucose metabolism may contribute to cellular dysfunction and angiopathy in diabetes. Uptake and utilization of glucose were studied in perfused blood vessels in which pulsatile flow and perfusion pressure were similar to those measured directly in vivo. Thoracic aortae isolated from 8-wk alloxan diabetic (D) and nondiabetic control rabbits were cannulated, tethered, and perfused with oxygenated buffer containing 7 or 25 mM glucose and tracer amounts of glucose-U/sup -14/ C. Norepinephrine (NE) (10/sup -6/ M) and/or insulin (I) (150 ..mu..U/ml) and albumin (0.2%) were added. NE-induced tension development increased glucose uptake 39% and /sup 14/CO/sub 2/ and lactate production 2.3-fold. With 7 mM glucose, marked decreases in glucose uptake (74%), /sup 14/CO/sub 2/ (68%), lactate (30%), total tissue glycogen (75%), and tissue phospholipids (70%) were observed in D. Addition of I or elevation of exogenous glucose to 25 mM normalized glucose uptake, but had differential effects on the pattern of substrate utilization. Thus, in D, there was a marked depression of vascular glucose metabolism that was partially reversed by addition of low concentrations of insulin or D levels of glucose.

Brown, B.J.; Crass, M.F. III

1986-03-05

46

Topological imaging of blood vessels by using diffusing light  

NASA Astrophysics Data System (ADS)

The topographic imaging technique using a backscattered diffusing light is proposed to monitor dynamics of blood vessels depending on the blood flow as a noncontact and noninvasive method. Their depth in skin tissues can be estimated by using the relation between a spatially-integrated backscattered intensity and a probability density function of an optical path-length. The topological image of the blood vessels is obtained per 0.08 sec by the developed system.

Kohama, Shotaro; Iwai, Toshiaki

2014-08-01

47

Recovery of testicular blood flow following ligation of testicular vessels  

SciTech Connect

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

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

1989-08-01

48

A Computational Model Predicting Disruption of Blood Vessel Development  

EPA Science Inventory

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 varie...

49

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

50

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

51

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

52

Allogeneic human tissue-engineered blood vessel  

PubMed Central

Background Arterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease; however, there is no available synthetic small-diameter vascular graft. Methods Tissue-engineered vessels were grown from human smooth muscle cells that were seeded on a biodegradable scaffold using a biomimetic perfusion system. The human tissue-engineered vessels (hTEV) were decellularized by a two-step process using a combination of detergents and hypertonic solutions. The mechanical characteristics were assessed by suture retention strength and burst pressure. The decellularized hTEV were implanted as aortic interpositional grafts in nude rats to evaluate in vivo performance as an arterial graft over a 6-week period. Results The human tissue-engineered structure formed a vessel composed of smooth muscle cells and the extracellular matrix proteins, including collagen. After decellularization, the collagen matrix remained intact while the cellular components were removed. The mechanical strength of the hTEV after decellularization was similar to human vein in vitro, with a burst pressure of 1,567 ± 384 mm Hg (n = 3) versus 1,680 ± 307 mm Hg for human saphenous vein. The hTEVs had a high patency rate (four of five grafts) without evidence of rupture or aneurysm over a 6-week period as an aortic interpositional graft in a nude rat model. Histologic analysis showed a thin neointima with a confluent endothelium and a subendothelial layer of smooth muscle cells on the explanted tissue-engineered vessels. Transmission electron microscopy on the explanted tissue demonstrated elastin formation in the neointima and intact residual collagen fibers from the tissue-engineered vessel. Conclusions The hTEV had a high patency rate and remained mechanically stable as an aortic interpositional graft in a nude rat. The vessel supported the growth of a neointima with endothelial cells and smooth muscle cells. The host remodeling suggested the engineered matrix had a positive effect to create a regenerated vascular graft. PMID:22056286

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

2012-01-01

53

Evaluation of blood vessel detection methods  

Microsoft Academic Search

We address the problem of evaluating the performance of algorithms for detecting curvilinear structures in medical images. As an exemplar we consider the detection of vessel trees which contain structures of variable width and contrast. Results for the conventional approach to evaluation, in which the detector output is compared directly with a groundtruth mask, tend to be dominated by the

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

2011-01-01

54

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

55

What Determines Blood Vessel Structure? Genetic Prespecification vs. Hemodynamics  

NSDL National Science Digital Library

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

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

2006-10-01

56

Brain blood vessel segmentation using line-shaped profiles.  

PubMed

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. PMID:24168875

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

2013-11-21

57

Visualizing blood vessel trees in three dimensions: clinical applications  

NASA Astrophysics Data System (ADS)

A connected network of blood vessels surrounds and permeates almost every organ of the human body. The ability to define detailed blood vessel trees enables a variety of clinical applications. This paper discusses four such applications and some of the visualization challenges inherent to each. Guidance of endovascular surgery: 3D vessel trees offer important information unavailable by traditional x-ray projection views. How best to combine the 2- and 3D image information is unknown. Planning/guidance of tumor surgery: During tumor resection it is critical to know which blood vessels can be interrupted safely and which cannot. Providing efficient, clear information to the surgeon together with measures of uncertainty in both segmentation and registration can be a complex problem. Vessel-based registration: Vessel-based registration allows pre-and intraoperative images to be registered rapidly. The approach both provides a potential solution to a difficult clinical dilemma and offers a variety of visualization opportunities. Diagnosis/staging of disease: Almost every disease affects blood vessel morphology. The statistical analysis of vessel shape may thus prove to be an important tool in the noninvasive analysis of disease. A plethora of information is available that must be presented meaningfully to the clinician. As medical image analysis methods increase in sophistication, an increasing amount of useful information of varying types will become available to the clinician. New methods must be developed to present a potentially bewildering amount of complex data to individuals who are often accustomed to viewing only tissue slices or flat projection views.

Bullitt, Elizabeth; Aylward, Stephen

2005-04-01

58

Bright Solitons on Continuous Wave Background in Blood Vessels  

NASA Astrophysics Data System (ADS)

The nonlinear Schrödinger equation (NLSE) with variable coefficients in blood vessels is discussed via an NLSE-based constructive method, and exact solutions are obtained including multi-soliton solutions with and without continuous wave backgrounds. The dynamical behaviors of these soliton solutions are studied. The solitonic propagation behaviors such as restraint and sustainment on continuous wave background are discussed by altering the value of dispersion parameter ?. Moreover, the longitude controllable behaviors are also reported by modulating the dispersion parameter ?. These results are potentially useful for future experiments in various blood vessels.

Xiang, Jia-Jie; Jiang, Hua-Jie; Dai, Chao-Qing; Wang, Yue-Yue

2014-03-01

59

[The size and suitability of blood vessels for transplantation into the knee of the dog].  

PubMed

An investigation of the size and suitability for the transplantation procedures of the knee blood vessels was made in 20 adult dogs with 40 extremities using the technique of injection of the arterial network through the femoral artery with the mixture of the methacrylic resin (SIGMAL R "Galenika", Belgrade) and the red ink. When the polymerisation of injected methacrylic resin was completed the specimens were exposed to either chemical or biological maceration of the tissues. Thirty-five specimens were chemically macerated using either 30% solution of hydrochloride acid or 40% potassium hydroxide. With this method bones were also destroyed and only the methacrylic vascular cast remained unaffected. Five specimens were exposed to the biological maceration using the insects (Dermestes vulpinus). This method proved to be better as the bones elements were not destroyed which allowed more precise study of vessel relations and topography. Calibre of the arteries was measured using the micromethod MEBA (Zagreb) with the accuracy of 0.01 mm. The main arterial vessels of the knee joint on the medial side are aa. saphena, genus descendes (branches of the femoral artery, then a. genus descendens (branches of the femoral artery, then a. genus medialis (branch of the popliteal artery), and on the lateral side are a. caudalis femoris distalis, (branch of the femoral artery), a genus lateralis (branch of the popliteal artery) and recurrent branches of the a. tibialis cranialis. Calibre of the femoral and popliteal arteries was over 2 mm which means that they are suitable for macrosurgical sutures, while the calibre of all other arteries was under 2 mm, and it is concluded that they are suitable only for microsurgical sutures. PMID:2327197

Miki?, Z; Mikes, M; Somer, T; Tubi?, M; Brankov, M

1990-01-01

60

Optically induced occlusion of single blood vessels in rodent neocortex.  

PubMed

The ability to form targeted vascular occlusions in small vessels of the brain is an important technique for studying the microscopic basis of cerebral ischemia. We describe two complementary methods that enable targeted occlusion of any single blood vessel within the upper 500 µm of adult rodent neocortex. Our goal is to generate highly localized regions of ischemia by blocking penetrating arterioles and ascending venules, which are bottlenecks of flow in the cortical angioarchitecture. One method, termed photothrombosis, makes use of linear optical absorption by a photosensitizer, transiently circulated in the blood stream, to induce a clot in a surface or near-surface segment of a vessel. The second method, termed plasma-mediated ablation, makes use of nonlinear optical interactions, without the need to introduce an exogenous absorber, to induce clots in subsurface segments of penetrating vessels, as well as subsurface microvessels and capillaries. The choice of the method for occlusion of individual vessels depends on the location of the vessels being studied and the objectives of the study. Here we describe concurrent high resolution in vivo imaging and auxiliary laser setups, occlusion protocols, and post hoc histological procedures. PMID:24298038

Shih, Andy Y; Nishimura, Nozomi; Nguyen, John; Friedman, Beth; Lyden, Patrick D; Schaffer, Chris B; Kleinfeld, David

2013-12-01

61

On the adaptive detection of blood vessels in retinal images.  

PubMed

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 rate (TPR) ranges from 80% to 91%, and their corresponding false positive rates (FPR) range from 2.8% to 5.5%. For abnormal images, the TPR ranges from 73.8% to 86.5% and the FPR ranges from 2.1% to 5.3%, respectively. In comparison with two published solution schemes that were also based on the STARE database, our scheme has lower FPR for the reported TPR measure. PMID:16485764

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

2006-02-01

62

Pattern Recognition Of Blood Vessel Networks In Ocular Fundus Images  

NASA Astrophysics Data System (ADS)

We propose a computer method of recognizing blood vessel networks in color ocular fundus images which are used in the mass diagnosis of adult diseases such as hypertension and diabetes. A line detection algorithm is applied to extract the blood vessels, and the skeleton patterns of them are made to analyze and describe their structures. The recognition of line segments of arteries and/or veins in the vessel networks consists of three stages. First, a few segments which satisfy a certain constraint are picked up and discriminated as arteries or veins. This is the initial labeling. Then the remaining unknown ones are labeled by utilizing the physical level knowledge. We propose two schemes for this stage : a deterministic labeling and a probabilistic relaxation labeling. Finally the label of each line segment is checked so as to minimize the total number of labeling contradictions. Some experimental results are also presented.

Akita, K.; Kuga, H.

1982-11-01

63

Blood vessels and feature points detection on retinal images  

Microsoft Academic Search

In this paper we present a method for the automatic extraction of blood vessels from retinal images, while capturing points of intersection\\/overlap and endpoints of the vascular tree. The algorithm performance is evaluated through a comparison with handmade segmented images available on the STARE project database (STructured Analysis of the REtina). The algorithm is performed on the green channel of

Edoardo Ardizzone; Roberto Pirrone; Orazio Gambino; Salvatore Radosta

2008-01-01

64

Blood Vessel Detection via a Multi-window Parameter Transform  

Microsoft Academic Search

A parallel algorithm to detect retinal blood vessels has been developed for use in an automated diabetic retinopathy detection system. Localized adaptive thresholding and a multi-window Radon transform (RT) are utilized to detect the vascular system in retinal images. Multi-window parameter transforms are intrinsically parallel and offer increased performance over conventional transforms. The image is adoptively thresholded and then the

Katia Estabridis; Rui J. P. De Figueiredo

2006-01-01

65

Directional Local Contrast Based Blood Vessel Detection in Retinal Images  

Microsoft Academic Search

In this paper, we proposed a novel algorithm to detect blood vessels on retinal images. By using directional local contrast as its detection feature, our algorithm is highly sensitive, fast and accurate. The algorithm only needs integral computing with very simple parameter adjustments and highly suitable for parallelization. It is much more robust to illumination conditions than intensity based counterparts

Ming Zhang; Jyh-charn Liu

2007-01-01

66

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

2010-01-01

67

Modeling Torsion of Blood Vessels in Surgical Simulation and Planning  

E-print Network

. of Surgery, National Taiwan University Hospital, Taipei, Taiwan, R.O.C. Abstract. This paper proposes the blood vessel's medial axis. Then, it uses rotation minimizing frame as a reference to model and measure, rotation minimizing frame Introduction Operations on 3D tubular models such as deformation, cutting

Leow, Wee Kheng

68

Blood vessel segmentation methodologies in retinal images--a survey.  

PubMed

Retinal vessel segmentation algorithms are a fundamental component of automatic retinal disease screening systems. This work examines the blood vessel segmentation methodologies in two dimensional retinal images acquired from a fundus camera and a survey of techniques is presented. The aim of this paper is to review, analyze and categorize the retinal vessel extraction algorithms, techniques and methodologies, giving a brief description, highlighting the key points and the performance measures. We intend to give the reader a framework for the existing research; to introduce the range of retinal vessel segmentation algorithms; to discuss the current trends and future directions and summarize the open problems. The performance of algorithms is compared and analyzed on two publicly available databases (DRIVE and STARE) of retinal images using a number of measures which include accuracy, true positive rate, false positive rate, sensitivity, specificity and area under receiver operating characteristic (ROC) curve. PMID:22525589

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

2012-10-01

69

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

70

Validation of the performance of a practical blood vessel imaging system to facilitate vessel punctures  

NASA Astrophysics Data System (ADS)

A practical system to visualize vessels underneath the skin has been developed, based on near-infrared (NIR) transillumination. A study in the clinical setting proved the system to be useful as a support in blood withdrawal in young children. During clinical application it was found that performance varied depending on vessel size, depth of vessels and surrounding lighting conditions. To gain more insight on the different variables that determine functioning of the system, we performed phantom studies. A combined liquid/solid phantom was fabricated with similar optical properties as the tissue layers of skin reported in literature at 850 nm. This phantom was used to estimate the depth of visibility in the relation to vessel size and darkness of the skin. Vessel contrast was determined analytically from images and evaluated by 3 independent observers. The knowledge gained from these experiments will be helpful to improve the imaging system and develop a solid phantom to be used as a gold standard to test the system under various clinical lighting conditions. The working range of the system was found to be appropriate to visualize the vessels used for the most procedures, such as blood withdrawal and placement of intravenous lines.

Cuper, Natascha J.; Verdaasdonk, Rudolf M.; de Roode, Rowland

2009-02-01

71

Plug effect of erythrocytes in capillary blood vessels.  

PubMed

As an idealized problem of the motion of blood in small capillary blood vessels, the low Reynolds number flow of plasma (a newtonian fluid) in a circular cylindrical tube involving a series of circular disks is studied. It is assumed in this study that the suspended disks are equally spaced along the axis of the tube, and that their centers remain on the axis of the tube and that their faces are perpendicular to the tube axis. The inertial force of the fluid due to the convective acceleration is neglected on the basis of the smallness of the Reynolds number. The solution of the problem is derived for a quasi-steady flow involving infinitesimally thin disks. The numerical calculation is carried out for a set of different combinations of the interdisk distance and the ratio of the disk radius to the tube radius. The ratio of the velocity of the disk to the average velocity of the fluid is calculated. The different rates of transport of red blood cells and of plasma in capillary blood vessels are discussed. The average pressure gradient along the axis of the tube is computed, and the dependence of the effective viscosity of the blood on the hematocrit and the diameter of the capillary vessel is discussed. PMID:5409778

Lew, H S; Fung, Y C

1970-01-01

72

Characteristics measurement for blood vessels diseases detection based on cone-beam CT images  

Microsoft Academic Search

This paper describes characteristics measurement for blood vessels diseases detection based on high-resolution 3D blood vessel images obtained by cone-beam CT. The important objective here is to show how the representation of blood vessel morphology can lead to feature measurement and identification of abnormal regions. In our method, the blood vessel structures are extracted by a graph description of blood

Yoshiki Kawata; Noboru Niki; Tatsuo Kumazaki

1995-01-01

73

Atherosclerosis of coronary blood vessels - local or systemic inflamation?  

PubMed

(Full text is available at http://www.manu.edu.mk/prilozi). The presence of atherosclerotic lesions in the blood vessels is a predisposition for the development and occurrence of acute ischaemic attacks. Bigger atherosclerotic lesions in the coronary blood vessels cause lumen occlusion, which is a cause of acute myocardial infarction. Endothelial dysfunction is defined as an ability of the endothelium to produce vasorelaxing nitric oxide (NO), or deregulation of the other vasoactive substances, such as angiotensin II and endothelin [13]. This definition describes endothelial dysfunction as an improper vasomotor constriction of the vessel, that leads to lumen occlusion of the already existing atherosclerotic lesions. According to the modern model, the development of atherosclerotic plaque and inappropriate endothelial NO production have a synergistic role in patho-physiological and molecular processes in the blood vessels [14]. Lesions in the coronary arteries are deposits of huge quantities of foamy cells and fibrous plaques. The thin fibrous plaques are 10-20% of the total plaque population and are the cause of 80-90% of clinical cases due to their ability to rupture [48]. According to all the results from published studies by far, it has been pointed out that the plaque stability, not the absolute size influences the rupture potential. Elucidating the risk factors that may modify in the atherogenesis and the consequent atherothrombic effect is the first step to this goal. Key words: Atherosclerotic lesion, endothelial dysfunction, vulnerable lesion, atherothrombosis. PMID:24566010

Pejkov, H; Kedev, S; Panov, S; Srbinovska-Kostovska, E; Lang, I

2013-01-01

74

Dimensional analysis of blood vessel images in real time  

NASA Astrophysics Data System (ADS)

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

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

1996-01-01

75

Proteoglycans and Vascular Residual Stress: Exposing a Hidden Mechanism for Regulating Blood Vessel Bio mechanics  

Microsoft Academic Search

Biomechanics plays a fundamental role in understanding how blood vessels function in the body, and how they adapt in response to abnormal loading conditions that accompany many devastating cardiovascular diseases. In particular, blood vessels contain so-called \\

Vikrum Thimmappa; Evren U. Azeloglu; Gerard A. Ateshian; Kevin D. Costa

76

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

77

Blood Vessel-Derived Acellular Matrix for Vascular Graft Application  

PubMed Central

To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6?mm) blood vessels, this study aimed to develop acellular matrix- (AM-) based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old) received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1?cm). The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels. PMID:25136610

Dall'Olmo, Luigi; Zanusso, Ilenia; Di Liddo, Rosa; Chioato, Tatiana; Bertalot, Thomas; Conconi, Maria Teresa

2014-01-01

78

Vessel wall detection and blood noise reduction in intravascular ultrasound imaging  

Microsoft Academic Search

Scattering from blood (blood noise) limits the contrast between the vessel wall and the lumen in intravascular ultrasound imaging. This makes it difficult to localize the vessel wall, especially in still images. This paper presents a method for automatic detection of vessel walls and reduction of blood noise based on correlation of the RF-signal between adjacent frames. Regions detected as

AAGE GRONNINGSAETER; B. A. J. Angelsen; A. Heimdal; H. Topr

1994-01-01

79

Moment Algorithms for Blood Vessel Detection in Infrared Images of LaserHeated Skin  

E-print Network

Moment Algorithms for Blood Vessel Detection in Infrared Images of Laser­Heated Skin S. Shoari, N in a three­dimensional image. The proposed method detects blood vessels in a three­dimensional tomographic in the laser treatment of hypervascular skin lesions. Key Words: Block detection, blood vessel, image

Bagherzadeh, Nader

80

Do Haematophagous Bugs Assess Skin Surface Temperature to Detect Blood Vessels?  

Microsoft Academic Search

BackgroundIt is known that some blood-sucking insects have the ability to reach vessels under the host skin with their mouthparts to feed blood from inside them. However, the process by which they locate these vessels remains largely unknown. Less than 5% of the skin is occupied by blood vessels and thus, it is not likely that insects rely on a

Raquel A. Ferreira; Claudio R. Lazzari; Marcelo G. Lorenzo; Marcos H. Pereira; Björn Brembs

2007-01-01

81

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

PubMed Central

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

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

2010-01-01

82

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

PubMed

The pulsatile flow of non-Newtonian fluid in a bifurcation model with a non-planar daughter branch is investigated numerically by using the Carreau-Yasuda model to take into account the shear thinning behavior of the analog blood fluid. The objective of this study is to deal with the influence of the non-Newtonian property of fluid and of out-of-plane curvature in the non-planar daughter vessel on wall shear stress (WSS), oscillatory shear index (OSI), and flow phenomena during the pulse cycle. The non-Newtonian property in the daughter vessels induces a flattened axial velocity profile due to its shear thinning behavior. The non-planarity deflects flow from the inner wall of the vessel to the outer wall and changes the distribution of WSS along the vessel, in particular in systole phase. Downstream of the bifurcation, the velocity profiles are shifted toward the flow divider, and low WSS and high shear stress temporal oscillations characterized by OSI occur on the outer wall region of the daughter vessels close to the bifurcation. Secondary motions become stronger with the addition of the out-of-plane curvature induced by the bending of the vessel, and the secondary flow patterns swirl along the non-planar daughter vessel. A significant difference between the non-Newtonian and the Newtonian pulsatile flow is revealed during the pulse cycle; however, reasonable agreement between the non-Newtonian and the rescaled Newtonian flow is found. Calculated results for the pulsatile flow support the view that the non-planarity of blood vessels and the non-Newtonian properties of blood are an important factor in hemodynamics and may play a significant role in vascular biology and pathophysiology. PMID:16488221

Chen, Jie; Lu, Xi-Yun

2006-01-01

83

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

E-print Network

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

Mohamad Rendi; Suprijadi; Sparisoma Viridi

2013-06-25

84

Modeling of blood vessel constriction in 2-D case using molecular dynamics method  

NASA Astrophysics Data System (ADS)

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

A. S., M. Rendi; Suprijadi, Viridi, S.

2014-03-01

85

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

E-print Network

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

Rendi, Mohamad; Viridi, Sparisoma

2013-01-01

86

Microprobes For Blood Flow Measurements In Tissue And Small Vessels  

NASA Astrophysics Data System (ADS)

Laser Doppler flowmetry is a method for the continuous and non-invasive recording of tissue blood flow. The method has already proved to be advantageous in a number of clinical as well as theoretical medical disciplines. In dermatology, plastic- and gastrointestinal surgery laser Doppler measurements have substantially contributed to increase knowledge of microvascular perfusion. In experimental medicine, the method has been used in the study of a great variety of microvascular problems. Spontaneous rhythmical variations, spatial and temporal fluctuations in human skin blood flow are mentioned as examples of problem areas in which new knowledge has been generated. The method has facilitated further investigations of the nature of spongeous bone blood flow, testis and kidney cortex blood flow. Recently we have showed that a variant of the laser Doppler method principle, using a single optical fiber, can be advantageous in deep tissue measurements. With this method laser light is transmitted bidirectionally in a single fiber. The tissue trauma which affects blood flow can be minimized by introducing small diameter fibers (0.1-0.5 mm). A special set-up utilizing the same basic principle has been used for the recording of blood flow in small vessels.

Oberg, P. A.; Salerud, E. G.

1988-04-01

87

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

88

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

89

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

90

A 3-D MOMENT BASED APPROACH FOR BLOOD VESSEL DETECTION AND QUANTIFICATION IN MRA  

E-print Network

A 3-D MOMENT BASED APPROACH FOR BLOOD VESSEL DETECTION AND QUANTIFICATION IN MRA P. Reuzé(*), J and orientation ; (4) rendering of the vessels. This detection and estimation scheme has been validated) tracking and the quantification of blood vessels from Magnetic Resonance Angiography (MRA). The approach

Paris-Sud XI, Université de

91

Non-linear Model Fitting to Parameterize Diseased Blood Vessels Alexandra La Cruz  

E-print Network

; Keywords: Visualization, Segmentation, Blood Vessel Detection 1 INTRODUCTION Peripheral arterial occlusiveNon-linear Model Fitting to Parameterize Diseased Blood Vessels Alexandra La Cruz Vienna University University Medical Center (a) (b) (c) Figure 1: Cross-section view of a vessel (a) and the best fitted model

92

Retinal blood vessel detection and tracking by matched Gaussian and Kalman filters  

Microsoft Academic Search

Detection and tracking algorithms of the blood vessel network in the retinal images are proposed. Two main groups of algorithms are employed for this task, i.e., scanning and tracking. According to the known blood vessel feature, a second-order derivative Gaussian matched filter is designed and used to locate the center point and width of a vessel in its cross sectional

O. Chutatape; Liu Zheng; S. M. Krishnan

1998-01-01

93

Vessel wall detection and blood noise reduction in intravascular ultrasound imaging  

Microsoft Academic Search

Scattering from blood limits the contrast between the vessel wall and the lumen in intravascular ultrasound imaging. This makes it difficult to localize the vessel wall, especially on still images. This paper presents a method for automatic detection of vessel walls and reduction of blood noise based on correlation of the RF-signal between adjacent frames. The ultrasound RF-signal is quadrature

Aage Gronningsaeter; Bjørn A. J. Angelsen; Andreas Heimdal; Hans G. Torp

1996-01-01

94

Non-linear Model Fitting to Parameterize Diseased Blood Vessels Alexandra La Cruz  

E-print Network

: Visualization, Segmentation, Blood Vessel Detection alacruz@cg.tuwien.ac.at matus.straka@assoc.oeaw.ac.at arnoldNon-linear Model Fitting to Parameterize Diseased Blood Vessels Alexandra La Cruz Vienna University University Medical Center (a) (b) (c) Figure 1: Cross-section view of a vessel (a) and the best fitted model

95

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; Joselíto J. Chua; Kotagiri Ramamohanarao

2007-01-01

96

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

97

Microfluidic strategy to investigate dynamics of small blood vessel function  

NASA Astrophysics Data System (ADS)

Resistance arteries (RAs, 30-300 microns in diameter) that are located within the terminal part of the vascular tree regulate the laminar perfusion of tissue with blood, via the peripheral vascular resistance, and hence controls the systemic blood pressure. The structure of RAs is adapted to actively controlling flow resistance by dynamically changing their diameter, which is non-linearly dependent on the temporal variation of the transmural pressure, perfusion flow rate and spatiotemporal changes in the chemical environment. Increases in systemic blood pressure (hypertension) resulting from pathologic changes in the RA response represent the primary risk factor for cardiovascular diseases. We use a microfluidic strategy to investigate small blood vessels by quantifying structural variations within the arterial wall, RA outer contour and diameter over time. First, we document the artery response to vasomotor drugs that were homogeneously applied at step-wise increasing concentration. Second, we investigate the response in the presence of well-defined axial and circumferential heterogeneities. Artery per- and superfusion is discussed based on microscale PIV measurements of the fluid velocity on both sides of the arterial wall. Structural changes in the arterial wall are quantified using cross-correlation and proper orthogonal decomposition analyses of bright-field micrographs.

Yasotharan, Sanjesh; Bolz, Steffen-Sebastian; Guenther, Axel

2010-11-01

98

Bioprinting of artificial blood vessels: current approaches towards a demanding goal.  

PubMed

Free-form fabrication techniques, often referred to as '3D printing', are currently tested with regard to the processing of biological and biocompatible materials in general and for fabrication of vessel-like structures in particular. Such computer-controlled methods assemble 3D objects by layer-wise deposition or layer-wise cross-linking of materials. They use, for example, nozzle-based deposition of hydrogels and cells, drop-on-demand inkjet-printing of cell suspensions with subsequent cross-linking, layer-by-layer cross-linking of synthetic or biological polymers by selective irradiation with light and even laser-induced deposition of single cells. The need of vessel-like structures has become increasingly crucial for the supply of encapsulated cells for 3D tissue engineering, or even with regard to future application such as vascular grafts. The anticipated potential of providing tubes with tailored branching geometries made of biocompatible or biological materials pushes future visions of patient-specific vascularized tissue substitutions, tissue-engineered blood vessels and bio-based vascular grafts. We review here the early attempts of bringing together innovative free-form manufacturing processes with bio-based and biodegradable materials. The presented studies provide many important proofs of concepts such as the possibility to integrate viable cells into computer-controlled processes and the feasibility of supplying cells in a hydrogel matrix by generation of a network of perfused channels. Several impressive results in the generation of complex shapes and high-aspect-ratio tubular structures demonstrate the potential of additive assembly methods. Yet, it also becomes obvious that there remain major challenges to simultaneously match all material requirements in terms of biological functions (cell function supporting properties), physicochemical functions (mechanical properties of the printed material) and process-related (viscosity, cross-linkability) functions, towards the demanding goal of biofabricating artificial blood vessels. PMID:24970571

Hoch, Eva; Tovar, Günter E M; Borchers, Kirsten

2014-11-01

99

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

PubMed Central

Background Valuable insights into the complex process of retinal vascular development can be gained using models with abnormal retinal vasculature. Two such models are the recently described mouse lines with mutations in Lama1, an important component of the retinal internal limiting membrane (ILM). These mutants have a persistence of the fetal vasculature of vitreous (FVV) but lack a primary retinal vascular plexus. The present study provides a detailed analysis of astrocyte and vascular development in these Lama1 mutants. Results Although astrocytes and blood vessels initially migrate into Lama1 mutant retinas, both traverse the peripapillary ILM into the vitreous by P3. Once in the vitreous, blood vessels anastomose with vessels of the vasa hyaloidea propria, part of the FVV, and eventually re-enter the retina where they dive to form the inner and outer retinal capillary networks. Astrocytes continue proliferating within the vitreous to form a dense mesh that resembles epiretinal membranes associated with persistent fetal vasculature and proliferative vitreoretinopathy. Conclusions Lama1 and a fully intact ILM are required for normal retinal vascular development. Mutations in Lama1 allow developing retinal vessels to enter the vitreous where they anastomose with vessels of the hyaloid system which persist and expand. Together, these vessels branch into the retina to form fairly normal inner retinal vascular capillary plexi. The Lama1 mutants described in this report are potential models for studying the human conditions persistent fetal vasculature and proliferative vitreoretinopathy. PMID:21999428

2011-01-01

100

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.

101

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.

102

Retinal blood vessel detection using frequency analysis and local-mean-interpolation filters  

Microsoft Academic Search

Unlike the existing automatic retinal blood vessel detection methods in which the vessels are detected by edge detection, thresholding or both (such as successive local probing) in the spatial domain, this paper presents a frequency-domain approach to the vessel detection problem. By having a frequency-domain analysis of the vessel signals, we found that the vessel signals between 0.1 and 0.25

Weining Tan; Yiming Wang; Samuel C. Lee

2001-01-01

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

[Efferent innervation of pulmonary blood vessels and bronchi in rat (an immunohistochemical study)].  

PubMed

In this investigation the peculiarities of innervation of bronchi and blood vessels of the lung were studied in 20 rats using immunohistochemical demonstration of synaptophysin and alpha-actin. The results obtained have showen that the densest innervation is typical for bronchial walls, particularly, for the muscular lamina. Synaptophysin-immunoreactive terminals (SFIT) were detected in the bronchi in close association with both circular bundles of smooth muscle cells and microganglia. Dense network of SFIT was found in the pulmonary vein--in its middle tunic formed by cardiomyocytes. In contrast to the bronchi and pulmonary vein, large branches of the pulmonary artery contained no SFIT. We briefly discuss the problem of the origin of the nerve fibers described and their functions and suggest that SFIT are formed by efferent fibers (axons) of neurons arising from either the intrapulmonary parasympathetic ganglia. PMID:23236891

Chumasov, E I; Voronchikhin, P A; Korzhevski?, D É

2012-01-01

105

[Association between the hemodynamic and rheological parameters in the micro blood vessels in vivo].  

PubMed

Considering the experimental data obtained earlier, regarding the shift velocity in the micro blood vessels in vivo, and general theses of liquid mechanics and rheology of the non-Newtonian liquids, a generalized ratio between the hemodynamic and rheological parameters in the micro blood vessels in vivo are overviewed. These are: pressure difference--DeltaP, volume of blood flow--Q, linear velocity of blood flow, viscosity of Newtonian liquid--k, effective viscosity of the blood in a vessel in vivo eta(effect), and index of rheological behavior--n, which was determined earlier in our laboratory. These parameters are observed in the live blood vessels of microcirculatory bed, in all regimes of the blood flow characteristic for the in-vivo vessels. PMID:15834187

Mamisashvili, V A; Mchedlishvili, N T; Chachanidze, E T; Urotadze, K N

2005-02-01

106

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

PubMed

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

Chen, Jie; Lu, Xi-Yun

2004-12-01

107

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

E-print Network

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

Chauhan, Vikash P.

108

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

109

A Fractional Derivative Approach for Robust Segmentation of Blood Vessels in Digital Fundus Retinal Images  

Microsoft Academic Search

Segmentation of Blood vessels is of key importance in the diagnosis of retinal images and early detection of diabetic retinopathy. In this paper, we propose a novel approach for segmentation of blood vessels in digital fundus retinal images using a fractional derivative-based edge operator. We have tested our algorithm on the standard DRIVE database. The results show significant improvement in

G. VijayaSaradhi; S. Balasubramanian; V. Chandrasekaran

2008-01-01

110

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

Microsoft Academic Search

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

Thitiporn Chanwimaluang; Guoliang Fan

2003-01-01

111

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

Microsoft Academic Search

The matched filter has been widely used in the detection of blood vessels of the human retina digital image. In this paper, the matched filter response to the detection of blood vessels is increased by proposing better filter parameters. These filter parameters are found by using an optimization procedure on 20 retina images of the DRIVE database. Comparisons with other

Mohammed Al-Rawi; Munib Qutaishat; Mohammed Arrar

2007-01-01

112

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

113

Thermal expansion of blood vessels in low cryogenic temperatures Part I: A new experimental device q  

E-print Network

Thermal expansion of blood vessels in low cryogenic temperatures Part I: A new experimental device of biological material during cryopreservation processes, the current study focuses on thermal expansion device for thermal expansion measurements of blood vessels in typical conditions of vitrifi- cation

Rabin, Yoed

114

Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation D. Ambrosi,1  

E-print Network

Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation A. Gamba,1 D. Ambrosi,1 17 March 2003) Experiments of in vitro formation of blood vessels show that cells randomly spread a fractal behavior at small scales, due to the process of migration and dynamical aggregation, followed

Ambrosi, Davide

115

Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation D. Ambrosi,1  

E-print Network

Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation A. Gamba,1 D. Ambrosi,1) Experiments of in vitro formation of blood vessels show that cells randomly spread on a gel matrix behavior at small scales, due to the process of migration and dynamical aggregation, followed at large

Preziosi, Luigi

116

Spectrophotometric investigation of skin blood vessels on the basis of color perception  

NASA Astrophysics Data System (ADS)

This paper investigates spectral reflectance of blood vessels in a skin tissue phantom. Measured reflectance spectra are slightly influenced by the vessel diameter, depth from the surface, and oxygen saturation state. We discuss a possibility of extracting the information on blood vessels from the reflectance spectra on the basis of color perception using the dominant wavelength in the CIE xy chromaticity diagram with the pseudo-reference white. The results show the usefulness of this method.

Aizu, Yoshihisa; Isokawa, Masaki; Yuasa, Tomonori; Mishina, Hiromichi; Asakura, Toshimitsu

1999-07-01

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

Imaging tissue engineered blood vessel mimics with optical coherence tomography  

NASA Astrophysics Data System (ADS)

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

Bonnema, Garret Thomas

119

A New Multiscale Representation for Shapes and Its Application to Blood Vessel Recovery  

E-print Network

In this paper, we will first introduce a novel multiscale representation (MSR) for shapes. Based on the MSR, we will then design a surface inpainting algorithm to recover 3D geometry of blood vessels. Because of the nature of irregular morphology in vessels and organs, both phantom and real inpainting scenarios were tested using our new algorithm. Successful vessel recoveries are demonstrated with numerical estimation of the degree of arteriosclerosis and vessel occlusion.

Bin Dong; Aichi Chien; Zuowei Shen; Stanley Osher

2009-05-14

120

Blood Vessel Deformations on Microsecond Time Scales by Ultrasonic Cavitation  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

121

Blood vessel deformations on microsecond time scales by ultrasonic cavitation.  

PubMed

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

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

2011-01-21

122

Blood Vessel Deformations on Microsecond Time Scales by Ultrasonic Cavitation  

PubMed Central

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

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

2011-01-01

123

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

PubMed

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

Deng, Zhong-Shan; Liu, Jing

2005-01-01

124

Computer simulation of local blood flow and vessel mechanics in a compliant carotid artery bifurcation model.  

PubMed

To investigate the effect of the distensible artery wall on the local flow field and to determine the mechanical stresses in the artery wall, a numerical model for the blood flow in the human carotid artery bifurcation has been developed. The wall displacement and stress analysis use geometrically non-linear shell theory where incrementally linearly elastic wall behavior is assumed. The flow analysis applies the time-dependent, three-dimensional, incompressible Navier-Stokes equations for non-Newtonian inelastic fluids. In an iteratively coupled approach the equations of the fluid motion and the transient shell equations are numerically solved using the finite element method. The study shows the occurring characteristics in carotid artery bifurcation flow, such as strongly skewed axial velocity in the carotid sinus with high velocity gradients at the internal divider wall and with flow separation at the outer common-internal carotid wall and at the bifurcation side wall. Flow separation results in locally low oscillating wall shear stress. Further strong secondary motion in the sinus is found. The comparison of the results for a rigid and a distensible wall model demonstrates quantitative influence of the vessel wall motion. With respect to the quantities of main interest, it can be seen, that flow separation and recirculation slightly decrease in the sinus and somewhat increase in the bifurcation side region, and the wall shear stress magnitude decreases by 25% in the distensible model. The global structure of the flow and stress patterns remains unchanged. The deformation analysis shows that the tangential displacements are generally lower by one order of magnitude than the normal directed displacements. The maximum deformation is about 16% of the vessel radius and occurs at the side wall region of the intersection of the two branches. The analysis of the maximum principal stresses at the inner vessel surface shows a complicated stress field with locally high gradients and indicates a stress concentration factor of 6.3 in the apex region. PMID:7657682

Perktold, K; Rappitsch, G

1995-07-01

125

Cell-free collagen-based scaffolds used for making blood vessels in cardiovascular surgery.  

PubMed

The present article deals with the technology of obtaining decellularized cell-free collagen-based scaffolds from arterial vessels and surgical assessment of the possibility of experimentally implanting them into the blood system of laboratory animals for experimental purposes. The study was performed on arterial vessels (n=60) and fragments of the human internal thoracic artery (n=20). Described herein is a method of obtaining a connective-tissue matrix of a blood vessel by means of vessel's perfusion for 2-3 hours with detergent solutions. Cell-free collagen-based conduits were implanted to a total of ten dogs. After the operation, the blood flow remained functional. The anastomoses established turned out to be leak-proof and the acellular vessels were able to withstand the haemodynamic load of the arterial blood flow. PMID:22929664

Akhmedov, Sh D; Afanas'ev, S A; Egorova, M V; Andreev, S L; Ivanov, A V; Rogovskaia, Yu V; Usov, V Yu; Shvedov, A N; Steinhoff, G

2012-01-01

126

A robust and accurate approach to automatic Blood Vessel detection and segmentation from Angiography X-ray images  

E-print Network

A robust and accurate approach to automatic Blood Vessel detection and segmentation from by a naiive vessel detection algorithm based on vesselness. Our approach will prune this set of putative seed, Robust Detection 1. INTRODUCTION Blood vessels are tubular objects, which are visible in the X

Kale, Amit

127

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 growth—a 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 process—a discovery that might provide a method for improving cancer drug delivery.

128

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

129

Blood vessel endothelial VEGFR-2 delays lymphangiogenesis: an endogenous trapping mechanism links lymph- and angiogenesis  

PubMed Central

Angio- and lymphangiogenesis are inherently related processes. However, how blood and lymphatic vessels regulate each other is unknown. This work introduces a novel mechanism explaining the temporal and spatial relation of blood and lymphatic vessels. Vascular endothelial growth factor-A (VEGF-A) surprisingly reduced VEGF-C in the supernatant of blood vessel endothelial cells, suggesting growth factor (GF) clearance by the growing endothelium. The orientation of lymphatic sprouting toward angiogenic vessels and away from exogenous GFs was VEGF-C dependent. In vivo molecular imaging revealed higher VEGF receptor (R)-2 in angiogenic tips compared with normal vessels. Consistently, lymphatic growth was impeded in the angiogenic front. VEGF-C/R-2 complex in the cytoplasm of VEGF-A–treated endothelium indicated that receptor-mediated internalization causes GF clearance from the extracellular matrix. GF clearance by receptor-mediated internalization is a new paradigm explaining various characteristics of lymphatics. PMID:20705758

Nakao, Shintaro; Zandi, Souska; Hata, Yasuaki; Kawahara, Shuhei; Arita, Ryoichi; Schering, Alexander; Sun, Dawei; Melhorn, Mark I.; Ito, Yasuhiro; Lara-Castillo, Nuria; Ishibashi, Tatsuro

2011-01-01

130

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

NASA Astrophysics Data System (ADS)

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

Cheema, Taqi Ahmad; Park, Cheol Woo

2013-08-01

131

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

PubMed Central

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

132

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

133

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

PubMed

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

Fasano, Antonio; Pavlova, Jevgenija; Sequeira, Adélia

2013-01-01

134

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

PubMed

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

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

2012-02-01

135

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

E-print Network

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 ...

Chauhan, Vikash P.

136

Blood vessel detection in retinal images and its application in diabetic retinopathy screening  

E-print Network

useful in tracking of disease progression, and for biometric authentication. In this dissertation, I proposed two algorithms to detect blood vessel maps in retina. The first algorithm is based on integration of a Gaussian tracing scheme and a Gabor...

Zhang, Ming

2009-05-15

137

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., 43°C) 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

138

Segmentation of brain blood vessels using projections in 3-D CT angiography images  

Microsoft Academic Search

Segmenting cerebral blood vessels is of great importance in diagnostic and clinical applications, especially in quantitative diagnostics and surgery on aneurysms and arteriovenous malformations (AVM). Segmentation of CT angiography images requires algorithms robust to high intensity noise, while being able to segment low-contrast vessels. Because of this, most of the existing methods require user intervention. In this work we propose

Danilo Babin; Ewout Vansteenkiste; Aleksandra Pizurica; Wilfried Philips

2011-01-01

139

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 ...

140

Momentum integral method for studying flow characteristics of blood through a stenosed vessel.  

PubMed

Taking into consideration the slip velocity at the wall of a blood vessel, a mathematical model is developed in the paper for the study of blood flow through a mammalian blood vessel in the presence of a stenosis. By employing the momentum integral technique, analytical expressions for the velocity profile, pressure gradient and skin-friction are derived. The condition for an adverse pressure gradient is also deduced. It is observed that the slip velocity bears the potential to influence the velocity distribution of blood to a remarkable extent and to reduce considerably the pressure-gradient as well as the skin-friction. PMID:2804272

Misra, J C; Kar, B K

1989-01-01

141

Diabetic Retinopathy: A Quadtree Based Blood Vessel Detection Algorithm Using RGB Components in Fundus Images  

Microsoft Academic Search

Blood vessel detection in retinal images is a fundamental step for feature extraction and interpretation of image content.\\u000a This paper proposes a novel computational paradigm for detection of blood vessels in fundus images based on RGB components\\u000a and quadtree decomposition. The proposed algorithm employs median filtering, quadtree decomposition, post filtration of detected\\u000a edges, and morphological reconstruction on retinal images. The

Ahmed Wasif Reza; Chantra Eswaran; Subhas Hati

2008-01-01

142

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

143

The Rheology of Blood Flow in a Branched Arterial System  

PubMed Central

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

Shibeshi, Shewaferaw S.; Collins, William E.

2006-01-01

144

Impact of cold ischemia on mitochondrial function in porcine hearts and blood vessels.  

PubMed

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

145

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 µm against all three experts) was within the range of the manually marked contours among the three readers (approximately 3.8 pixels respectively 18 µm 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, Matthaus; Wenner, Yaroslava; Strohmayr, Elisabeth; Preising, Markus; Friedburg, Christoph; Meyer zu Bexten, Erdmuthe; Lorenz, Birgit; Stieger, Knut

2012-01-01

146

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

PubMed Central

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

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

2010-01-01

147

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

148

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

PubMed

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

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

2013-01-01

149

Different role of CD73 in leukocyte trafficking via blood and lymph vessels.  

PubMed

CD73 is involved in the extracellular ATP metabolism by dephosphorylating extracellular AMP to adenosine and thus regulating permeability of the blood vessels and leukocyte traffic into the tissues. It is also present on lymphatic vessels where its distribution and function have not been characterized. We found that CD73 is expressed on a subpopulation of afferent lymph vessels but is absent on efferent lymphatics, unlike LYVE-1 and podoplanin, which are expressed on both types of lymphatics. The extracellular nucleotide metabolism on lymphatic endothelium differs from that on blood vessel endothelium as lymphatic endothelium has lower NTPDase and higher ecto-5'-nucleotidase/CD73 activity than blood vascular endothelium. In knockout mice, the lack of CD73 on lymphocytes decreases migration of lymphocytes to the draining lymph nodes more than 50% while CD73-deficient lymph vessels mediate lymphocyte trafficking as efficiently as the wild-type lymphatics. Thus, although endothelial CD73 is important for permeability and leukocyte extravasation in blood vessels, it does not have a role in these functions on lymphatics. Instead, lymphocyte CD73 is intimately involved in lymphocyte migration via afferent lymphatic vessels. PMID:21346249

Ålgars, Annika; Karikoski, Marika; Yegutkin, Gennady G; Stoitzner, Patrizia; Niemelä, Jussi; Salmi, Marko; Jalkanen, Sirpa

2011-04-21

150

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

151

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

PubMed Central

Vascular disease results in the decreased utility and decreased availability of autologus vascular tissue for small diameter (< 6 mm) vessel replacements. While synthetic polymer alternatives to date have failed to meet the performance of autogenous conduits, tissue-engineered replacement vessels represent an ideal solution to this clinical problem. Ongoing progress requires combined approaches from biomaterials science, cell biology, and translational medicine to develop feasible solutions with the requisite mechanical support, a non-fouling surface for blood flow, and tissue regeneration. Over the past two decades interest in blood vessel tissue engineering has soared on a global scale, resulting in the first clinical implants of multiple technologies, steady progress with several other systems, and critical lessons-learned. This review will highlight the current inadequacies of autologus and synthetic grafts, the engineering requirements for implantation of tissue-engineered grafts, and the current status of tissue-engineered blood vessel research. PMID:23181145

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

2012-01-01

152

Perihemorheology: the bridge between the vessel-blood organ and the organs it penetrates.  

PubMed

Perihemorheology concerns the rheology of fluids and structures in the perivascular spaces. Furthermore, the term refers to the exchanges of rheological processes between the vessel-blood organ and its surrounding tissues, as well as in reverse. In 1960, the vessel wall and the circulating blood were considered by the author as an entity which in 1981 he postulated as an organ, named the 'vessel-blood organ', penetrating all other organs. This communication is not a survey but is intended to stimulate biomedical thinking regarding the importance of perihemorheology. The significance of the endoendothelial fibrin(ogenin) lining (EEFL) and fibrin(ogenin) as constituent of the interendothelial cement and the basement membrane in relation to perihemorheology is stressed. The role of albumin in the exchanges between hemorheology and perihemorheology is discussed. The protein content, as found by Witte, in the perivascular spaces as compared to the blood is emphasized regarding the importance of interrelations between the vessel-blood organ and rheological processes in the perivascular spaces. Recent studies, particularly by Laurent and his group, pertaining to hyaluronan in perivascular spaces and the blood demonstrate also the importance of the interrelationship between hemorheology and perihemorheology. The term 'blood-brain barrier', considered no longer to be adequate, is replaced by the term 'basement membrane-brain barrier'. It is proposed that the basement membrane of the vessel-blood organ penetrating the brain may contain certain constituents, unknown thus far, and may have a different structure from the basement membrane of the vessel-blood organ penetrating organs other than the brain. PMID:2690966

Copley, A L

1989-01-01

153

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot  

E-print Network

Painting blood vessels and atherosclerotic plaques with an adhesive drug depot Christian J 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

Strynadka, Natalie

154

Characteristics of blood vessels forming “sausages-on-a-string” patterns during hypertension  

NASA Astrophysics Data System (ADS)

A phenomenon of alternate constrictions and dilatations in blood vessels has been studied for over 50 years. Recently, a theory has been presented involving a Rayleigh type instability. We analyze the model in terms of the lengths of the deformations in relation to the wall thickness, blood pressure and stress. Analytical and numerical results obtained are consistent with experimental data.

Ravnsborg Beierholm, Ulrik; Christian Brings Jacobsen, Jens; Holstein-Rathlou, Niels-Henrik; Alstrøm, Preben

2007-03-01

155

Cooling effect of thermally significant blood vessels in perfused tumor tissue during thermal therapy  

Microsoft Academic Search

This purpose of this article was focused on the cooling effects of thermally significant blood vessels on the extent of thermal lesion during heating treatments. The thermal modeling here based on the Pennes bio-heat transfer equation, describing the heat transfer of perfused tumor tissue, and the energy transport equation governing the heat convection and diffusion of the blood flow. The

Tzu-Ching Shih; Hao-Li Liu; Allen Tzyy-Leng Horng

2006-01-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

157

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

PubMed

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

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

2014-11-01

158

Recognition method of lung nodules using blood vessel extraction techniques and 3D object models  

NASA Astrophysics Data System (ADS)

In this paper, we propose a method for reducing false positives in X-ray CT images using ridge shadow extraction techniques and 3D geometric object models. Suspicious shadows are detected by our variable N-quoit (VNQ) filter, which is a type of mathematical morphology filter. This filter can detect lung cancer shadows with the sensitivity over 95[%], but it also detects many false positives which are mainly related to blood vessel shadows. We have developed two algorithms to distinguish lung nodule shadows from blood vessel shadows. In the first algorithm, the ridge shadows, which come from blood vessels, are emphasized by our Tophat by Partial Reconstruction filter which is also a type of mathematical morphology filter. And then, the region of the ridge shadow is extracted using binary distance transformation. In the second algorithm, we propose a recognition method of nodules using 3D geometric lung nodule and blood vessel models. The anatomical knowledge about the 3D structures of nodules and blood vessels can be reflected in recognition process. By applying our new method to actual CT images (37 patient images), a good result has been acquired.

Fukano, Gentaro; Takizawa, Hotaka; Shigemoto, Kanae; Yamamoto, Shinji; Matsumoto, Tohru; Tateno, Yukio; Iinuma, Takeshi

2003-05-01

159

Descending branch of the lateral circumflex femoral artery as a recipient vessel for vascularized fibular grafts: Clinical case series.  

PubMed

Vascularized fibular grafts (VFG) are used for the treatment of femoral head avascular necrosis, osteomyelitis, nonunions, and excessive bone defects. Mostly the ascending branch of the lateral circumflex femoral artery (LCFA) or first or second perforating branch of the profound femoral artery is used for the customary recipient vessel. In this report, an alternative technique of using descending branch of LCFA in VFG surgery and its clinical results are reported. Sixteen patients (13 men and 3 women) underwent VFG surgery between the years 2005 and 2012. Predicted etiologies were: ANFH in 10 hips, traumatic femur neck pseudoarthrosis in 4 hips, tumor in 1 hip, and 1 femur shaft defect due to osteomyelitis. Patients' average age at the time of surgery was 29 years (range, 14-43 years). All patients were treated with VFG. All of the grafts survived and none of the patients needed any revision surgery. One had superficial wound infection, one developed peroneal nerve palsy, and one had trochanteric bursitis. The follow-up time was 36 months (range 20-72). It is believed that the descending branch of LCFA is a reliable alternative for anastomosis in VFG surgery. © 2014 Wiley Periodicals, Inc. Microsurgery 34:633-637, 2014. PMID:25052056

Gokhan, Meric; Ulusal, Ali Engin; Atik, Aziz; Sargin, Serdar; Ulusal, Betul; Sukru Sahin, Mehmet

2014-11-01

160

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

161

New algorithm for detecting smaller retinal blood vessels in fundus images  

NASA Astrophysics Data System (ADS)

About 4.1 million Americans suffer from diabetic retinopathy. To help automatically diagnose various stages of the disease, a new blood-vessel-segmentation algorithm based on spatial high-pass filtering was developed to automatically segment blood vessels, including the smaller ones, with low noise. Methods: Image database: Forty, 584 x 565-pixel images were collected from the DRIVE image database. Preprocessing: Green-band extraction was used to obtain better contrast, which facilitated better visualization of retinal blood vessels. A spatial highpass filter of mask-size 11 was applied. A histogram stretch was performed to enhance contrast. A median filter was applied to mitigate noise. At this point, the gray-scale image was converted to a binary image using a binary thresholding operation. Then, a NOT operation was performed by gray-level value inversion between 0 and 255. Postprocessing: The resulting image was AND-ed with its corresponding ring mask to remove the outer-ring (lens-edge) artifact. At this point, the above algorithm steps had extracted most of the major and minor vessels, with some intersections and bifurcations missing. Vessel segments were reintegrated using the Hough transform. Results: After applying the Hough transform, both the average peak SNR and the RMS error improved by 10%. Pratt's Figure of Merit (PFM) was decreased by 6%. Those averages were better than [1] by 10-30%. Conclusions: The new algorithm successfully preserved the details of smaller blood vessels and should prove successful as a segmentation step for automatically identifying diseases that affect retinal blood vessels.

LeAnder, Robert; Bidari, Praveen I.; Mohammed, Tauseef A.; Das, Moumita; Umbaugh, Scott E.

2010-03-01

162

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

163

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

164

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

PubMed Central

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

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

2013-01-01

165

Mussel-inspired cell-adhesion peptide modification for enhanced endothelialization of decellularized blood vessels.  

PubMed

Enhanced endothelialization of tissue-engineered blood vessels is essential for vascular regeneration and function of engineered vessels. In this study, mussel-inspired surface chemistry of polydopamine (pDA) coatings are applied to functionalize decellularized vein matrix (DVM) with extracellular matrix-derived cell adhesion peptides (RGD and YIGSR). DVMs engineered with pDA-peptides enhance focal adhesion, metabolic activity, and endothelial differentiation of human endothelial progenitor cells (EPCs) derived from cord blood and embryonic stem cells compared with EPCs on non-coated or pDA-coated DVMs. These results indicate that pDA-peptide functionalization may contribute to enhanced, rapid endothelialization of DVM surfaces by promoting adhesion, proliferation, and differentiation of circulating EPCs. Ultimately, this approach may be useful for improving in vivo patency and function of decellularized matrix-based blood vessels. PMID:24831738

Lee, Jung Seung; Lee, Kihong; Moon, Sung-Hwan; Chung, Hyung-Min; Lee, Jun Hyup; Um, Soong Ho; Kim, Dong-Ik; Cho, Seung-Woo

2014-08-01

166

Apelin Inhibits Diet-Induced Obesity by Enhancing Lymphatic and Blood Vessel Integrity  

PubMed Central

Angiogenesis is tightly associated with the outgrowth of adipose tissue, leading to obesity, which is a risk factor for type 2 diabetes and hypertension, mainly because expanding adipose tissue requires an increased nutrient supply from blood vessels. Therefore, induction of vessel abnormality by adipokines has been well-studied, whereas how altered vascular function promotes obesity is relatively unexplored. Also, surviving Prox1 heterozygous mice have shown abnormal lymphatic patterning and adult-onset obesity, indicating that accumulation of adipocytes could be closely linked with lymphatic function. Here, we propose a new antiobesity strategy based on enhancement of lymphatic and blood vessel integrity with apelin. Apelin knockout (KO) mice fed a high-fat diet (HFD) showed an obese phenotype associated with abnormal lymphatic and blood vessel enlargement. Fatty acids present in the HFD induced hyperpermeability of endothelial cells, causing adipocyte differentiation, whereas apelin promoted vascular stabilization. Moreover, treatment of apelin KO mice with a selective cyclooxygenase-2 inhibitor, celecoxib, that were fed an HFD improved vascular function and also attenuated obesity. Finally, apelin transgenic mice showed decreased subcutaneous adipose tissue attributable to inhibition of HFD-induced hyperpermeability of vessels. These results indicate that apelin inhibits HFD-induced obesity by enhancing vessel integrity. Apelin could serve as a therapeutic target for treating obesity and related diseases. PMID:23378608

Sawane, Mika; Kajiya, Kentaro; Kidoya, Hiroyasu; Takagi, Masaya; Muramatsu, Fumitaka; Takakura, Nobuyuki

2013-01-01

167

Numerical analysis and experimental observation of guidewire motion in a blood vessel model.  

PubMed

We have developed a computer-based system to simulate a guidewire in blood vessels for surgical planning, intra-operative assistance, and to facilitate the design of new guidewires. In this study, we compared simulation results with experimental results for validation of the simulation system. First, we inserted a commercial guidewire into a poly (vinyl alcohol) hydrogel blood vessel model using a two-axis automatic stage and measured the position of the guidewire tip and the contact force between the guidewire and the vessel. The experimental apparatus can be used not only for the validation of numerical analyses, but also as a simulation system. Second, similarly to the experiment, the motion of the guidewire in the blood vessel model was calculated when the proximal part of the guidewire model was pushed and twisted. The model of the guidewire is constructed with viscoelastic springs and segments, and the proximal part of the guidewire model is constrained by the fixed catheter model. Collisions between the guidewire and the vessel are calculated, and the contact forces are determined according to the stiffness of the vessel wall. The same tendency was seen in the trajectories and the contact force of both the experimental and simulated guidewire tips. PMID:25292450

Takashima, Kazuto; Tsuzuki, Shotaro; Ooike, Atomu; Yoshinaka, Kiyoshi; Yu, Kaihong; Ohta, Makoto; Mori, Koji

2014-12-01

168

Apelin inhibits diet-induced obesity by enhancing lymphatic and blood vessel integrity.  

PubMed

Angiogenesis is tightly associated with the outgrowth of adipose tissue, leading to obesity, which is a risk factor for type 2 diabetes and hypertension, mainly because expanding adipose tissue requires an increased nutrient supply from blood vessels. Therefore, induction of vessel abnormality by adipokines has been well-studied, whereas how altered vascular function promotes obesity is relatively unexplored. Also, surviving Prox1 heterozygous mice have shown abnormal lymphatic patterning and adult-onset obesity, indicating that accumulation of adipocytes could be closely linked with lymphatic function. Here, we propose a new antiobesity strategy based on enhancement of lymphatic and blood vessel integrity with apelin. Apelin knockout (KO) mice fed a high-fat diet (HFD) showed an obese phenotype associated with abnormal lymphatic and blood vessel enlargement. Fatty acids present in the HFD induced hyperpermeability of endothelial cells, causing adipocyte differentiation, whereas apelin promoted vascular stabilization. Moreover, treatment of apelin KO mice with a selective cyclooxygenase-2 inhibitor, celecoxib, that were fed an HFD improved vascular function and also attenuated obesity. Finally, apelin transgenic mice showed decreased subcutaneous adipose tissue attributable to inhibition of HFD-induced hyperpermeability of vessels. These results indicate that apelin inhibits HFD-induced obesity by enhancing vessel integrity. Apelin could serve as a therapeutic target for treating obesity and related diseases. PMID:23378608

Sawane, Mika; Kajiya, Kentaro; Kidoya, Hiroyasu; Takagi, Masaya; Muramatsu, Fumitaka; Takakura, Nobuyuki

2013-06-01

169

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

PubMed

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

Iida, N

1989-01-01

170

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

Microsoft Academic Search

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

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

2011-01-01

171

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.

172

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

173

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

174

Role of tissue factor in embryonic blood vessel development  

Microsoft Academic Search

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

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

1996-01-01

175

Vessel Wall and Blood Flow Dynamics in Arterial Disease  

Microsoft Academic Search

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

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

1981-01-01

176

Peristaltic Pumping of Blood Through Small Vessels of Varying Cross-section  

E-print Network

The paper is devoted to a study of the peristaltic motion of blood in the micro-circulatory system. The vessel is considered to be of varying cross-section. The progressive peristaltic waves are taken to be of sinusoidal nature. Blood is considered to be a Herschel-Bulkley fluid. Of particular concern here is to investigate the effects of amplitude ratio, mean pressure gradient, yield stress and the power law index on the velocity distribution, streamline pattern and wall shear stress. On the basis of the derived analytical expression, extensive numerical calculations have been made. The study reveals that velocity of blood and wall shear stress are appreciably affected due to the non-uniform geometry of blood vessels. They are also highly sensitive to the magnitude of the amplitude ratio and the value of the fluid index.

J. C. Misra; S. Maiti

2010-06-01

177

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

178

Peristaltic Pumping of Blood in micro-vessels of Non-uniform Cross-section  

Microsoft Academic Search

The paper is devoted to a study of the peristaltic motion of blood in the micro-circulatory system. The vessel is considered of non-uniform cross-section. The progressive peristaltic waves are taken to be of sinusoidal nature. The Reynolds number is considered to be small. Blood is considered to be a Herschel-Bulkley fluid. Of particular concern here is to investigate the effects

J. C. Misra; S. Maiti

2010-01-01

179

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

180

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.

Sajadi, Atefeh Sadat; Sabzpoushan, Seyed Hojat

2014-01-01

181

Generalization of geometrical flux maximizing flow on Riemannian manifolds for improved volumetric blood vessel segmentation.  

PubMed

Geometric flux maximizing flow (FLUX) is an active contour based method which evolves an initial surface to maximize the flux of a vector field on the surface. For blood vessel segmentation, the vector field is defined as the vectors specified by vascular edge strengths and orientations. Hence, the segmentation performance depends on the quality of the detected edge vector field. In this paper, we propose a new method for level set based segmentation of blood vessels by generalizing the FLUX on a Riemannian manifold (R-FLUX). We consider a 3D scalar image I(x) as a manifold embedded in the 4D space (x, I(x)) and compute the image metric by pullback from the 4D space, whose metric tensor depends on the vessel enhancing diffusion (VED) tensor. This allows us to devise a non-linear filter which both projects and normalizes the original image gradient vectors under the inverse of local VED tensors. The filtered gradient vectors pertaining to the vessels are less sensitive to the local image contrast and more coherent with the local vessel orientation. The method has been applied to both synthetic and real TOF MRA data sets. Comparisons are made with the FLUX and vesselsness response based segmentations, indicating that the R-FLUX outperforms both methods in terms of leakage minimization and thiner vessel delineation. PMID:22664135

Gooya, Ali; Liao, Hongen; Sakuma, Ichiro

2012-09-01

182

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

183

Bioconjugated gold nanoparticles accelerate the growth of new blood vessels through redox signaling.  

PubMed

We have designed and developed novel pro-angiogenic bio-synthesized gold nanoconjugates (b-Au-HP) that make new blood vessels, as observed by several in vitro and in vivo assays, suggesting their future potential applications in alternative treatment strategies for wound healing, cardiovascular diseases (CVD) and ischemic diseases using a nanomedicine approach. PMID:25298204

Nethi, Susheel Kumar; Mukherjee, Sudip; Veeriah, Vimal; Barui, Ayan Kumar; Chatterjee, Suvro; Patra, Chitta Ranjan

2014-10-23

184

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

PubMed Central

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

Yoshizawa, Keiko; Taguchi, Tetsushi

2014-01-01

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

Enhancement of blood vessels in digital fundus photographs via the application of multiscale line operators  

Microsoft Academic Search

We employed multiscale line operators (MSLO) in order to segment blood vessels in digital fundus images. Separately, a median filter technique was used in order to provide results that were compared to those of the MSLO. The green channel of the colour image was used, and both sets of results were further enhanced by subsequently employing a simple “randomly seeded”

D. J. J. Farnell; F. N. Hatfield; P. Knox; M. Reakes; S. Spencer; D. Parry; S. P. Harding

2008-01-01

187

Automated segmentation of blood vessels for detection of proliferative diabetic retinopathy  

Microsoft Academic Search

Retinal image analysis is very effective in early detection and diagnosis of diabetic retinopathy. Diabetic retinopathy is a progressive disease and is broadly classify into two stages i.e. Non proliferative diabetic retinopathy (NPDR) and Proliferative diabetic retinopathy (PDR). A sign of PDR is the appearance of new blood vessels in fundus area and inside optic disc known as neovascularization. The

M. Usman Akram; Ibaa Jamal; Anam Tariq; Junaid Imtiaz

2012-01-01

188

Parallel multiscale feature extraction and region growing: application in retinal blood vessel detection  

Microsoft Academic Search

This paper presents a parallel implementation based on insight segmentation and registration toolkit for a multiscale feature extraction and region growing algorithm, applied to retinal blood vessels segmentation. This implementation is capable of achieving an accuracy (Ac) comparable to its serial counterpart (about 92%), but 8 to 10 times faster. In this paper, the Ac of this parallel implementation is

Miguel A. Palomera-Pérez; M. Elena Martínez-Pérez; Héctor Benítez-Pérez; Jorge Luis Ortega-Arjona

2010-01-01

189

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.

190

Thermal expansion of blood vessels in low cryogenic temperatures, Part II: Vitrification with VS55,  

E-print Network

Thermal expansion of blood vessels in low cryogenic temperatures, Part II: Vitrification with VS55 of biological materials in cryopreservation processes, the current study focuses on thermal expansion during a unified thermal expansion anal- ysis throughout the entire cryogenic temperature range by compiling

Rabin, Yoed

191

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

Microsoft Academic Search

The Magnetic Resonance Submarine (MR-Sub) project is a first attempt to validate a new propulsion method for future small magnetically controlled microdevices suited for minimally invasive applications in blood vessels. A Magnetic Res- onance Imaging (MRI) system provides the driving force in three dimensions to a ferromagnetic core that could be embedded onto a specialised microdevice. The paper describes preliminary

Jean-Baptiste Mathieu; L'Hocine Yahia; PQ Montréal

2005-01-01

192

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

E-print Network

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

Erdem, Erkut

193

Image Sequence Analysis for on line Observation of Thrombus Formation in Blood Vessels  

E-print Network

Image Sequence Analysis for on line Observation of Thrombus Formation in Blood Vessels Ralf T�NJES Institut für Theoretische Nachrichtentechnik und Informationsverarbeitung, Division: Automatic Image--Mail: toenjes@tnt.uni--hannover.de Abstract. An image analysis system for in vivo observation of thrombus

194

Study in Nature: MicroRNAs Hold Promise For Treating Diseases in Blood Vessels  

E-print Network

RNAs). These small, single-stranded molecules of ribonucleic acid (RNA), discovered in the Victor Ambros lab in 1993 A newly discovered mechanism controls whether muscle cells in blood vessels hasten the development of both, fine-tune protein levels in all cells of the body. The GICD team discovered that miRNAs control VSMC

Goldman, Steven A.

195

Mayo Clinic-led study unravels biological pathway that controls the leakiness of blood vessels  

Cancer.gov

A research team led by scientists at Mayo Clinic in Florida have decoded the entire pathway that regulates leakiness of blood vessels, a condition that promotes a wide number of disorders, such as heart disease, cancer growth and spread, inflammation and respiratory distress.

196

A meshless rheological model for blood-vessel interaction in endovascular simulation.  

PubMed

A meshless rheological model is proposed for medical simulation of vascular procedures. Due to the complexity of rheologic models involved in endovascular simulations, delivering a high level of interactivity with realistic biomechanical feedback is still a challenge. In this paper, we propose a particle-based rheologic modeling method for virtual catheterisation training applications. The effect of blood rheology has been simulated through a smoothed particle hydrodynamics (SPH) formulation of non-Newtonian flow. By modeling vessel wall structure as virtual particles, a pure Lagrange particle formulation for fluid-structure interaction (FSI) is purposed for modeling the blood-vessel interaction. We further propose a flow-related thrombus (clot) formation-dissolution model based on our fluid-solid interaction framework. A physics processing API (PhysX) friendly implementation is proposed for incorporating the rheological properties of blood and vessel wall into our framework. Results have demonstrated the feasibility of employing our proposed meshfree framework in simulating blood-vessel interaction and clotting behaviors which are essential to endovascular simulations. Having benefited from the elegant formulation of Lagrangian particle interaction, interactive framerates of the simulation can be maintained under hardware-acceleration. PMID:20868705

Chui, Yim-Pan; Heng, Pheng-Ann

2010-12-01

197

Factors associated with access blood flow in native vessel arteriovenous fistulae  

Microsoft Academic Search

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

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

2004-01-01

198

A Blood Vessel Model Constructed from Collagen and Cultured Vascular Cells  

Microsoft Academic Search

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

Crispin B. Weinberg; Eugene Bell

1986-01-01

199

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; Popovic, Zoran; Huang, Peigen; Bawendi, Moungi G.; Boucher, Yves; Jain, Rakesh K.

2013-01-01

200

Non-Newtonian characteristics of peristaltic flow of blood in micro-vessels  

E-print Network

Of concern in the paper is a generalized theoretical study of the non-Newtonian characteristics of peristaltic flow of blood through micro-vessels, e.g. arterioles. The vessel is considered to be of variable cross-section and blood to be a Herschel-Bulkley type of fluid. The progressive wave front of the peristaltic flow is supposed sinusoidal/straight section dominated (SSD) (expansion/contraction type); Reynolds number is considered to be small with reference to blood flow in the micro-circulatory system. The equations that govern the non-Newtonian peristaltic flow of blood are considered to be non-linear. The objective of the study has been to examine the effect of amplitude ratio, mean pressure gradient, yield stress and the power law index on the velocity distribution, wall shear stress, streamline pattern and trapping. It is observed that the numerical estimates for the aforesaid quantities in the case of peristaltic transport of the blood in a channel are much different from those for flow in an axisymmetric vessel of circular cross-section. The study further shows that peristaltic pumping, flow velocity and wall shear stress are significantly altered due to the non-uniformity of the cross-sectional radius of blood vessels of the micro-circulatory system. Moreover, the magnitude of the amplitude ratio and the value of the fluid index are important parameters that affect the flow behaviour. Novel features of SSD wave propagation that affect the flow behaviour of blood have also been discussed.

S. Maiti; J. C. Misra

2011-08-05

201

A Shape-Directed Scaling Method for Fundus Image with Maintenance to Blood-Vessel Shapes and Color Reality  

Microsoft Academic Search

When digitized fundus images are used in medicine, important information for clinicians' diagnosis should be maintained well after scaling. Conventional scaling methods select the interpolation kernel based on Shannon's sampling theorem which is only appropriate for band-limited signals and usually generate image with jaggy noise or blurred blood-vessel shapes that the tortuosity and diameter change of blood vessels which are

Kai Sheng; Keisuke Kameyama; Kazuo Toraichi; Yoshinori Mitamura; Kazuki Katagishi; Yasuo Morooka; Yasuhiro Ohmiya

2005-01-01

202

Design and Implementation of a Unique Blood-Vessel Detection Algorithm towards Early Diagnosis of Diabetic Retinopathy  

Microsoft Academic Search

Diabetic retinopathy (DR), a major complication of diabetes and the leading cause of new cases of blindness among adults, can be cured by the early and precise detection of the disease. An important aspect of DR is the micro-vascular changes that cause detectable changes in the appearance of retinal blood vessels. In this paper, we propose a new blood-vessel detection

Sumeet Dua; Naveen Kandiraju; Hilary W. Thompson

2005-01-01

203

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

E-print Network

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

Kleinfeld, David

204

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

PubMed Central

We have numerically investigated the axisymmetric motion of a finite-sized nearly occluding air bubble through a shear-thinning Casson fluid flowing in blood vessels of circular cross section. The numerical solution entails solving a two-layer fluid model—a cell-free layer and a non-Newtonian core together with the gas bubble. This problem is of interest to the field of rheology and for gas embolism studies in health sciences. The numerical method is based on a modified front-tracking method. The viscosity expression in the Casson model for blood (bulk fluid) includes the hematocrit [the volume fraction of red blood cells (RBCs)] as an explicit parameter. Three different flow Reynolds numbers, Reapp=?lUmaxd/?app, in the neighborhood of 0.2, 2, and 200 are investigated. Here, ?l is the density of blood, Umax is the centerline velocity of the inlet Casson profile, d is the diameter of the vessel, and ?app is the apparent viscosity of whole blood. Three different hematocrits have also been considered: 0.45, 0.4, and 0.335. The vessel sizes considered correspond to small arteries, and small and large arterioles in normal humans. The degree of bubble occlusion is characterized by the ratio of bubble to vessel radius (aspect ratio), ?, in the range 0.9???1.05. For arteriolar flow, where relevant, the Fahraeus-Lindqvist effects are taken into account. Both horizontal and vertical vessel geometries have been investigated. Many significant insights are revealed by our study: (i) bubble motion causes large temporal and spatial gradients of shear stress at the “endothelial cell” (EC) surface lining the blood vessel wall as the bubble approaches the cell, moves over it, and passes it by; (ii) rapid reversals occur in the sign of the shear stress (+ ? ? ? +) imparted to the cell surface during bubble motion; (iii) large shear stress gradients together with sign reversals are ascribable to the development of a recirculation vortex at the rear of the bubble; (iv) computed magnitudes of shear stress gradients coupled with their sign reversals may correspond to levels that cause injury to the cell by membrane disruption through impulsive compression and stretching; and (v) for the vessel sizes and flow rates investigated, gravitational effects are negligible. PMID:18851139

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

2009-01-01

205

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

206

Simulation of Molecular Signaling in Blood Vessels: Software Design and Application to Atherogenesis  

E-print Network

This paper presents a software platform, named BiNS2, able to simulate diffusion-based molecular communications with drift inside blood vessels. The contribution of the paper is twofold. First a detailed description of the simulator is given, under the software engineering point of view, by highlighting the innovations and optimizations introduced. Their introduction into the previous version of the BiNS simulator was needed to provide to functions for simulating molecular signaling and communication potentials inside bounded spaces. The second contribution consists of the analysis, carried out by using BiNS2, of a specific communication process happening inside blood vessels, the atherogenesis, which is the initial phase of the formation of atherosclerotic plaques, due to the abnormal signaling between platelets and endothelium. From a communication point of view, platelets act as mobile transmitters, endothelial cells are fixed receivers, sticky to the vessel walls, and the transmitted signal is made of bursts of molecules emitted by platelets. The simulator allows evaluating the channel latency and the footprint on the vessel wall of the transmitted signal as a function of the transmitter distance from the vessels wall, the signal strength, and the receiver sensitivity.

Luca Felicetti; Mauro Femminella; Gianluca Reali

2013-06-01

207

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

208

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

209

Quantification of cerebral arterial blood volume and cerebral blood flow using MRI with modulation of tissue and vessel (MOTIVE) signals.  

PubMed

Regional cerebral arterial blood volume (CBVa) and blood flow (CBF) can be quantitatively measured by modulation of tissue and vessel (MOTIVE) signals, enabling separation of tissue signal from blood. Tissue signal is selectively modulated using magnetization transfer (MT) effects. Blood signal is changed either by injection of a contrast agent or by arterial spin labeling (ASL). The measured blood volume represents CBVa because the contribution from venous blood was insignificant in our measurements. Both CBVa and CBF were quantified in isoflurane-anesthetized rats at 9.4T. CBVa obtained using a contrast agent was 1.1 +/- 0.5 and 1.3 +/- 0.6 ml/100 g tissue (N = 10) in the cortex and caudate putamen, respectively. The CBVa values determined from ASL data were 1.0 +/- 0.3 ml/100 g (N = 10) in both the cortex and the caudate putamen. The match between CBVa values determined by both methods validates the MOTIVE approach. In ASL measurements, the overestimation in calculated CBF values increased with MT saturation levels due to the decreasing contribution from tissue signals, which was confirmed by the elimination of blood with a contrast agent. Using the MOTIVE approach, accurate CBF values can also be obtained. PMID:16032688

Kim, Tae; Kim, Seong-Gi

2005-08-01

210

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

PubMed

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

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

2013-11-01

211

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.

212

Plasminogen Activator of the Blood Vessels in Tumours and in Carrageenin-induced Granulomas  

PubMed Central

Fibrinolytic activity in tumours was studied by the fibrin slide technique. The tumour cells were inactive and fibrinolysis was seen only in areas with young blood vessels. In carrageenin-induced granulomas at 6 days the fibrinolytic activity was small and confined to mature veins, but from 7-14 days activity was high in zones containing young vessels supplying the terminal capillary buds; these latter showed no activity. In old fibrosed granulomas there was no fibrinolytic activity. The vascular permeability changes of inflammation (detected by the colloidal carbon technique) showed no correlation with fibrinolytic activity, and systemic injection of inflammatory agents had no effect on the fibrinolytic activity of the vessels. These findings are discussed in relationship to tumour vascularization. ImagesFigs. 5-8Figs. 1-4 PMID:5547651

Pick, C. R.; Cater, D. B.

1971-01-01

213

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

214

Shear-activated nanotherapeutics for drug targeting to obstructed blood vessels.  

PubMed

Obstruction of critical blood vessels due to thrombosis or embolism is a leading cause of death worldwide. Here, we describe a biomimetic strategy that uses high shear stress caused by vascular narrowing as a targeting mechanism--in the same way platelets do--to deliver drugs to obstructed blood vessels. Microscale aggregates of nanoparticles were fabricated to break up into nanoscale components when exposed to abnormally high fluid shear stress. When coated with tissue plasminogen activator and administered intravenously in mice, these shear-activated nanotherapeutics induce rapid clot dissolution in a mesenteric injury model, restore normal flow dynamics, and increase survival in an otherwise fatal mouse pulmonary embolism model. This biophysical strategy for drug targeting, which lowers required doses and minimizes side effects while maximizing drug efficacy, offers a potential new approach for treatment of life-threatening diseases that result from acute vascular occlusion. PMID:22767894

Korin, Netanel; Kanapathipillai, Mathumai; Matthews, Benjamin D; Crescente, Marilena; Brill, Alexander; Mammoto, Tadanori; Ghosh, Kaustabh; Jurek, Samuel; Bencherif, Sidi A; Bhatta, Deen; Coskun, Ahmet U; Feldman, Charles L; Wagner, Denisa D; Ingber, Donald E

2012-08-10

215

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

216

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

PubMed

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

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

2012-12-26

217

Fusion of uniluminal vascular spheroids: a model for assembly of blood vessels.  

PubMed

We evaluated the self-assembly properties of uniluminal vascular spheroids having outer layers of vascular smooth muscle cells and a contiguous inner layer of endothelial cells lining a central lumen. We showed that while pairs of uniluminal vascular spheroids suspended in culture medium fused to form a larger diameter spheroidal structure, spheroids in collagen hydrogels formed elongated structures. These findings highlight the potential use of uniluminal vascular spheroids as modules to engineer blood vessels. We also demonstrate that uniluminal vascular spheroid fusion conforms to models describing the coalescence of liquid drops. Furthermore, the fusion of uniluminal vascular spheroids in vitro closely resembled the in vivo process by which the descending aorta forms from the fusion of the paired dorsal aortae during embryonic development. Together, the findings indicate that tissue liquidity underlies uniluminal vascular spheroid fusion and that in vivo anastomosis of blood vessels may involve a similar mechanism. PMID:19918756

Fleming, Paul A; Argraves, W Scott; Gentile, Carmine; Neagu, Adrian; Forgacs, Gabor; Drake, Christopher J

2010-02-01

218

Gene Delivery System Targets Tumor Blood Vessels in Dogs with Cancer  

Cancer.gov

In a preliminary study of pet dogs with naturally occurring cancer, researchers have developed a way to target delivery of a gene to tumor blood vessels, where the gene product damages the vessels, disrupting blood flow to the tumors but not to the surrounding tissue. The delivery method was well tolerated, and in some dogs, the size of tumors decreased or remained stable. This study provides valuable information that may aid in the design of future clinical trials. These are the first results of the Comparative Oncology Trials Consortium, a novel multicenter network sponsored by NCI to integrate cancers that naturally develop in dogs into the developmental path of new therapies for cancers in humans.

219

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

220

Thermal expansion of blood vessels in low cryogenic temperatures Part I: A new experimental device  

PubMed Central

As part of the ongoing effort to study the mechanical behavior of biological material during cryopreservation processes, the current study focuses on thermal expansion of blood vessels at low cryogenic temperatures. The current paper (Part I) describes a new experimental device for thermal expansion measurements of blood vessels in typical conditions of vitrification, which are associated with rapid cooling rates. For validation purposes, the thermal strain of frozen arteries in the absence of cryoprotectants was measured, and found to be about 10% larger than that of polycrystalline water; this observation agrees with literature data. The companion paper (Part II) reports on experimental results of cryoprotectants permeated with VS55, DP6 and 7.05M DMSO at high cooling rates applicable to vitrification. PMID:16487503

Jimenez Rios, Jorge L.; Rabin, Yoed

2006-01-01

221

Diffuse reflectance spectra of skin blood vessels and their color analysis  

NASA Astrophysics Data System (ADS)

This paper presents experimental studies on diffuse reflectance spectra of blood in cylindrical glass vessels embedded in the Intralipid solution as a skin tissue model, and also f human skin surfaces. The measured spectra are mainly governed by the absorption characteristics of a small amount of blood added into the Intralipid medium. To evaluate quantitatively diffuse reflectance spectra, we employed the color perception on the basis of the CIE x-y chromaticity diagram. Results for the skin tissue model were found to coincide with those for veins in the human skin tissue.

Aizu, Yoshihisa; Nishidate, Izumi; Yokoi, Naomichi; Yuasa, Tomonori; Mishina, Hiromichi

2001-06-01

222

[Aporocotyle theragrae (Trematoda: Aporocotylidae) from the blood vessel of Theragra chalcogramma].  

PubMed

Two fully matured specimens were collected from the blood vessel of two fish, Theragra chalcogramma, which was bought at the Emun market of Seoul in May, 1985. The blood fluke has no pharynx and suckers. Its body surface was covered with minute spines forming fan-shaped groups, 15 microns long. The intestine was H-shaped, and the ratio of esophageal length to body length was 1:6.1-6.8. Irregular shaped testes were 109-114 in number, occupying the intercecal space from cecal bifurcation to the genital pore. The present species was identified as Aporocotyle theragrae. This is the first report of the species in Korea. PMID:1297414

Chu, J P; Chu, J K; Lee, Y Y; Youn, M M

1992-12-01

223

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.

224

Automated localisation of the optic disc, fovea, and retinal blood vessels from digital colour fundus images  

PubMed Central

AIM—To recognise automatically the main components of the fundus on digital colour images.?METHODS—The main features of a fundus retinal image were defined as the optic disc, fovea, and blood vessels. Methods are described for their automatic recognition and location. 112 retinal images were preprocessed via adaptive, local, contrast enhancement. The optic discs were located by identifying the area with the highest variation in intensity of adjacent pixels. Blood vessels were identified by means of a multilayer perceptron neural net, for which the inputs were derived from a principal component analysis (PCA) of the image and edge detection of the first component of PCA. The foveas were identified using matching correlation together with characteristics typical of a fovea—for example, darkest area in the neighbourhood of the optic disc. The main components of the image were identified by an experienced ophthalmologist for comparison with computerised methods.?RESULTS—The sensitivity and specificity of the recognition of each retinal main component was as follows: 99.1% and 99.1% for the optic disc; 83.3% and 91.0% for blood vessels; 80.4% and 99.1% for the fovea.?CONCLUSIONS—In this study the optic disc, blood vessels, and fovea were accurately detected. The identification of the normal components of the retinal image will aid the future detection of diseases in these regions. In diabetic retinopathy, for example, an image could be analysed for retinopathy with reference to sight threatening complications such as disc neovascularisation, vascular changes, or foveal exudation.?? PMID:10413690

Sinthanayothin, C.; Boyce, J.; Cook, H.; Williamson, T.

1999-01-01

225

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

226

Blood Vessel Detection in Retinal Images by Shape-Based Multi-threshold Probing  

Microsoft Academic Search

We propose a novel approach to blood vessel detection in retinal images using shape-based multi-threshold probing. On an image\\u000a set with hand-labeled ground truth our algorithm quantitatively demonstrates superior performance over the basic thresholding\\u000a and another method recently reported in the literature. The core of our algorithm, classification-based multi-threshold probing,\\u000a represents a general framework of segmentation that has not been

Xiaoyi Jiangand; Daniel Mojon

2001-01-01

227

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

Microsoft Academic Search

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

Luca Antiga; Bogdan Ene-iordache; Andrea Remuzzi

2003-01-01

228

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

Microsoft Academic Search

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

Wei Zhang; Chong Wang; Ghassan S. Kassab

2007-01-01

229

A discrete-particle model of blood dynamics in capillary vessels  

Microsoft Academic Search

We investigate the mechanism of aggregation of red blood cells (RBC) in capillary vessels. We use a discrete-particle model in 3D to model the flow of plasma and RBCs within a capillary tube. This model can accurately capture the scales from 0.001 to 100 ?m, far below the scales that can be modeled numerically with classical computational fluid dynamics. The flexible

Witold Dzwinel; Krzysztof Boryczko; David A. Yuen

2003-01-01

230

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.

231

Lack of tolerance in forearm blood vessels in man to glyceryl trinitrate.  

PubMed Central

1. Nitrate tolerance is a clinical problem. The cause is not known but it has been suggested that tolerance to organic nitrates occurs within the blood vessels to reduce sensitivity to the drug. We have determined the sensitivity of human forearm resistance vessels and veins to glyceryl trinitrate (GTN) at the beginning and end of a 7 day period of GTN administration in healthy volunteers using a clinically relevant dose of transdermal drug. 2. Eight healthy volunteers completed the study which entailed measurement of change in forearm venous compliance and change in forearm blood flow following intraarterial infusions of two doses of glyceryl trinitrate (0.5 and 2.0 micrograms min-1) before, after 2 h and after 7 days of transdermal GTN administration using one 10 mg patch each 24 h. 3. Changes in venous compliance and blood flow were measured by venous occlusion plethysmography using a basal infusion of noradrenaline (1 microgram min-1) to increase venous tone. 4. Noradrenaline produced the expected decrease in forearm blood flow and venous compliance. The effect of locally infused GTN on venous compliance and forearm blood flow was similar on the three study days. In particular there was no significant difference in the response to GTN following 7 days transdermal administration compared with that after 2 h. 5. We conclude from this study that local vascular tolerance to GTN is unlikely to explain the clinical problem of nitrate tolerance, and that other mechanisms such as neurohumoral activation may be important. PMID:8054249

Cheesman, A R; Benjamin, N

1994-01-01

232

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, Lindsay Crowl; Fogelson, Aaron L.

2013-01-01

233

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

234

Human Blood-Vessel-Derived Stem Cells for Tissue Repair and Regeneration  

PubMed Central

Multipotent stem/progenitor cells with similar developmental potentials have been independently identified from diverse human tissue/organ cultures. The increasing recognition of the vascular/perivascular origin of mesenchymal precursors suggested blood vessels being a systemic source of adult stem/progenitor cells. Our group and other laboratories recently isolated multiple stem/progenitor cell subsets from blood vessels of adult human tissues. Each of the three structural layers of blood vessels: intima, media, and adventitia has been found to include at least one precursor population, that is, myogenic endothelial cells (MECs), pericytes, and adventitial cells (ACs), respectively. MECs and pericytes efficiently regenerate myofibers in injured and dystrophic skeletal muscles as well as improve cardiac function after myocardial infarction. The applications of ACs in vascular remodeling and angiogenesis/vasculogenesis have been examined. Our recent finding that MECs and pericytes can be purified from cryogenically banked human primary muscle cell culture further indicates their potential applications in personalized regenerative medicine. PMID:22500099

Chen, Chien-Wen; Corselli, Mirko; Peault, Bruno; Huard, Johnny

2012-01-01

235

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

PubMed Central

Optical imaging of changes in total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2) provides a means to investigate brain hemodynamic regulation. However, high-resolution transcranial imaging remains challenging. In this study, we applied a novel functional photoacoustic microscopy technique to probe the responses of single cortical vessels to left forepaw electrical stimulation in mice with intact skulls. Functional changes in HbT, CBV, and SO2 in the superior sagittal sinus and different-sized arterioles from the anterior cerebral artery system were bilaterally imaged with unambiguous 36 × 65-?m2 spatial resolution. In addition, an early decrease of SO2 in single blood vessels during activation (i.e., ‘the initial dip') was observed. Our results indicate that the initial dip occurred specifically in small arterioles of activated regions but not in large veins. This technique complements other existing imaging approaches for the investigation of the hemodynamic responses in single cerebral blood vessels. PMID:22472612

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

2012-01-01

236

A discrete-particle model of blood dynamics in capillary vessels.  

PubMed

We investigate the mechanism of aggregation of red blood cells (RBC) in capillary vessels. We use a discrete-particle model in 3D to model the flow of plasma and RBCs within a capillary tube. This model can accurately capture the scales from 0.001 to 100 microm, far below the scales that can be modeled numerically with classical computational fluid dynamics. The flexible viscoelastic red blood cells and the walls of the elastic vessel are made up of solid particles held together by elastic harmonic forces. The plasma is represented by a system of dissipative fluid particles. Modeling has been carried out using 1 to 3 million solid and fluid particles. We have modeled the flow of cells with vastly different shapes, such as normal and "sickle" cells. The two situations involving a straight capillary and a pipe with a choking point have been considered. The cells can coagulate in spite of the absence of adhesive forces in the model. We conclude that aggregation of red blood cells in capillary vessels can be stimulated by depletion forces and hydrodynamic interactions. The cluster of "sickle" cells formed in the choking point of the capillary efficiently decelerates the flow, while normal cells can pass through. These qualitative results from our first numerical results accord well with the laboratory findings. PMID:12600784

Dzwinel, Witold; Boryczko, Krzysztof; Yuen, David A

2003-02-01

237

Selective occlusion of tumor blood vessels by targeted delivery of an antibody-photosensitizer conjugate.  

PubMed

The irregular vasculature and high interstitial pressure of solid tumors hinder the delivery of cytotoxic agents to cancer cells. As a consequence, the doses of chemotherapy necessary to achieve complete tumor eradication are associated with unacceptably high toxicities. The selective thrombosis of tumor blood vessels has been postulated as an alternative avenue for combating cancer, depriving tumors of nutrients and oxygen and causing an avalanche of tumor cell deaths. The human antibody L19, specific to the EDB domain of fibronectin, a marker of angiogenesis, is capable of selective in vivo localization around tumor blood vessels and is thus a suitable agent for delivering toxic payloads to the tumor neovasculature. Here we show that a chemical conjugate of the L19 antibody with the photosensitizer bis(triethanolamine)Sn(IV) chlorin e(6), after intravenous injection and irradiation with red light, caused an arrest of tumor growth in mice with subcutaneous tumors. By contrast, a photosensitizer conjugate obtained with an antibody of identical pharmacokinetic properties but irrelevant specificity did not exhibit a significant therapeutic effect. These results confirm that vascular targeting strategies, aimed at the selective occlusion/disruption of tumor blood vessels, have a significant anticancer therapeutic potential and encourage the use of antibody-photosensitizer conjugates for the therapy of superficial tumors and possibly other angiogenesis-related pathologies. PMID:16217760

Fabbrini, Monica; Trachsel, Eveline; Soldani, Patrizia; Bindi, Stefano; Alessi, Patrizia; Bracci, Luisa; Kosmehl, Hartwig; Zardi, Luciano; Neri, Dario; Neri, Paolo

2006-04-01

238

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

239

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

240

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

PubMed

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

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

2014-07-01

241

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

NASA Astrophysics Data System (ADS)

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

Haacke, E. Mark

2002-03-01

242

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

Microsoft Academic Search

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

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

2011-01-01

243

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

PubMed Central

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

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

2013-01-01

244

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

Cancer.gov

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

245

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

PubMed Central

Objective: Persistent Type 2 endoleaks (PT2) after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) are associated with increased adverse outcomes, including aneurysmal sac enlargement and rupture. The aim of this study was to report early clinical outcomes of coil embolization (CE) to aortic branched vessels prior to EVAR and assess the effectiveness of this strategy in terms of prevention of sac growth due to PT2. Materials and Methods: Between May 2007 and April 2012, EVAR was performed for 215 cases, divided into two groups (150 cases in Group A, before introduction of CE; 21 in Group B, receiving CE before EVAR). Early clinical outcomes were compared between groups. Results: Fifty percent of cases in Group B had a marked reduction of aneurysmal sac diameter based on multi-detector row computed tomographic angiography (MDCTA) findings at the 6-month follow-up after EVAR, whereas, only 25% of cases in Group A had shrinkage of the aneurysmal sac during the same time period after EVAR. Conclusion: This strategy has the possibility of improving late outcomes of EVAR by reducing endoleak volumes beforehand. PMID:23825498

2013-01-01

246

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

247

Ultrastructure of blood vessels in the head kidney of the carp, Cyprinus carpio.  

PubMed Central

The ultrastructural features of blood vessels were examined by transmission and scanning electron microscopy in the perfused and nonperfused head kidney of the carp. They consisted mainly of the sinusoidal capillaries, arterioles, veins and portal veins. The sinusoidal capillaries were composed of endothelial cells that frequently exhibited large pores and an indistinct basal lamina. Some endothelial cells were trabecular in shape and protruded into the lumen. The reticular cells frequently attached to the outside of the endothelial cells, and macrophages were located on the luminal and abluminal surfaces of the endothelial cells. The arterioles possessed continuous endothelial cells with a thick basal lamina, continuous smooth muscle layers and a thick adventitia with collagen fibres and reticular cells. The veins were characterised by fenestrated endothelial cells and thin connective tissue. The portal veins were composed of continuous electron-lucent endothelial cells and thick layers of reticular cells and collagen fibres. The differences between the endothelial cells in each blood vessel probably reflect the various functions of the carp head kidney. The ultrastructural features of the sinusoids and the portal veins resemble those of lymphatic vessels of mammals and appear to relate to macrophage and lymphoid cell migration and proliferation in the carp head kidney. Images Fig. 2 Figs 3,4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:7649788

Imagawa, T; Kitagawa, H; Uehara, M

1994-01-01

248

The phylogeny of the fine structure of blood vessels and lymphatics: similarities and differences.  

PubMed

As animals increased in size, various modifications had to come into being to carry nutrients and waste around the body. Different phyla solved the various problems differently; sometimes there was convergent evolution. In invertebrates the endothelial cells are often widely separated from each other; permeability is limited by the pericyte layer; the reverse occurs in vertebrates. In primitive chordates small peripheral vessels often consist only of the basement membrane, and even this may be partly missing; the more centrally one looks, the more the endothelial cells become continuous. Fenestrae appeared first in the agnatha, but only become common in the elasmobranchs. Increased size and activity necessitated still larger blood hydrostatic pressure and increased blood colloidal osmotic pressures to balance this. Since the permeability of the vessels could not be reduced, much more protein (and fluid) had to leak to the tissues. So the lymphatic system had to evolve. This is first seen in the torpedoes and fully evolved in the bony fishes. However, the small venous vessels of the elasmobranchs have openable inter-endothelial junctions and other structures very similar to those of the initial lymphatics. Apart from the absence of fenestrae in lymphatics, or when this system is injected with a tracer, it is not always possible to tell them apart with the electron microscope. There are, however, various differences between them which will help to differentiate them. PMID:3444359

Casley-Smith, J R

1987-12-01

249

Acellular blood vessels combined human hair follicle mesenchymal stem cells for engineering of functional arterial grafts.  

PubMed

Tissue-engineered vessels offer options for autologous vascular grafts in cardiovascular repair and regeneration. The experiments aimed to construct functional arterial grafts by combining human hair follicle mesenchymal stem cells (HF-MSCs) with acellular umbilical arteries. We isolated mesenchymal stem cells from human hair follicles. Under appropriate culture conditions, these cells displayed CD44, CD90 and CD105, and exhibited the potential for differentiation to adipocytes, osteoblasts and chondrocytes. Very promisingly, HF-MSCs expressed the vascular smooth muscle specific markers in the presence of transforming growth factor-?. We created acellular arterial scaffolds by digesting human umbilical arteries with trypsin and sodium dodecyl sulfate. These acellular arterial scaffolds retained major components of the extracellular matrix. The mechanical properties of these acellular arterial scaffolds were very similar to those of native blood vessels. We then seeded HF-MSCs into acellular arterial scaffolds and found that they still expressed vascular smooth muscle specific markers. The arterial grafts derived from HF-MSCs demonstrated vasoreactivity in response to humoral constrictors. We constructed arterial grafts that are very close to native blood vessels in their structures and physiological functions. These properties suggest that these arterial grafts could be used as small diameter arterial grafts for cardiovascular repair and regeneration. PMID:25023659

Gao, Yunhe; Liu, Feilin; Zhang, Lihong; Su, Xuejin; Liu, Jin Yu; Li, Yulin

2014-10-01

250

Adaptable three-dimensional Monte Carlo modeling of imaged blood vessels in skin  

NASA Astrophysics Data System (ADS)

In order to reach a higher level of accuracy in simulation of port wine stain treatment, we propose to discard the typical layered geometry and cylindrical blood vessel assumptions made in optical models and use imaging techniques to define actual tissue geometry. Two main additions to the typical 3D, weighted photon, variable step size Monte Carlo routine were necessary to achieve this goal. First, optical low coherence reflectometry (OLCR) images of rat skin were used to specify a 3D material array, with each entry assigned a label to represent the type of tissue in that particular voxel. Second, the Monte Carlo algorithm was altered so that when a photon crosses into a new voxel, the remaining path length is recalculated using the new optical properties, as specified by the material array. The model has shown good agreement with data from the literature. Monte Carlo simulations using OLCR images of asymmetrically curved blood vessels show various effects such as shading, scattering-induced peaks at vessel surfaces, and directionality-induced gradients in energy deposition. In conclusion, this augmentation of the Monte Carlo method can accurately simulate light transport for a wide variety of nonhomogeneous tissue geometries.

Pfefer, T. Joshua; Barton, Jennifer K.; Chan, Eric K.; Ducros, Mathieu G.; Sorg, Brian S.; Milner, Thomas E.; Nelson, J. Stuart; Welch, Ashley J.

1997-06-01

251

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

252

Differences in inositol phosphate production in blood vessels of normotensive and spontaneously hypertensive rats.  

PubMed Central

1. Total inositol phosphate formation was measured in labelled femoral and iliac arteries and veins of 14 week-old spontaneously hypertensive rats (SHR) and age-matched Wistar Kyoto (WKY) controls, either unstimulated or in the presence of noradrenaline. 2. Basal levels of [3H]-inositol phosphates and [3H]-phosphatidylinositol were significantly enhanced in SHR femoral artery, but not in the other 3 vessels, compared with WKY. 3. Noradrenaline stimulated phosphoinositide hydrolysis in all four vessels of SHR and WKY. Pretreatment with prazosin (10(-7)-10(-6) M) but not with yohimbine (10(-7) M), inhibited the noradrenaline-induced inositol phosphate formation indicating an alpha 1-adrenoceptor-mediated response. 4. In the femoral artery of SHR compared to WKY, [3H]-inositol phosphate accumulation induced by noradrenaline (10(-7)-10(-5) M) was significantly reduced when expressed relative to basal values although the response to higher concentrations (10(-4)-10(-3) M) was not altered. In contrast, a significant reduction of inositol phosphates was seen only with 10(-7) M noradrenaline when absolute values were compared. In the other three vessels, no difference in noradrenaline-induced [3H]-inositol phosphate formation was observed between strains. 5. These data suggest that phosphoinositide hydrolysis-mediated by alpha 1-adrenoceptors may be reduced in some but not all blood vessels of adult SHR. PMID:1797298

Vila, E.; Macrae, I. M.; Reid, J. L.

1991-01-01

253

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

PubMed

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

2010-01-01

254

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

255

An ensemble classification-based approach applied to retinal blood vessel segmentation.  

PubMed

This paper presents a new supervised method for segmentation of blood vessels in retinal photographs. This method uses an ensemble system of bagged and boosted decision trees and utilizes a feature vector based on the orientation analysis of gradient vector field, morphological transformation, line strength measures, and Gabor filter responses. The feature vector encodes information to handle the healthy as well as the pathological retinal image. The method is evaluated on the publicly available DRIVE and STARE databases, frequently used for this purpose and also on a new public retinal vessel reference dataset CHASE_DB1 which is a subset of retinal images of multiethnic children from the Child Heart and Health Study in England (CHASE) dataset. The performance of the ensemble system is evaluated in detail and the incurred accuracy, speed, robustness, and simplicity make the algorithm a suitable tool for automated retinal image analysis. PMID:22736688

Fraz, Muhammad Moazam; Remagnino, Paolo; Hoppe, Andreas; Uyyanonvara, Bunyarit; Rudnicka, Alicja R; Owen, Christopher G; Barman, Sarah A

2012-09-01

256

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

257

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 (5.5–7 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

258

Notch Regulation of Hematopoiesis, Endothelial Precursor Cells, and Blood Vessel Formation: Orchestrating the Vasculature  

PubMed Central

The development of the vascular system begins with the formation of hemangioblastic cells, hemangioblasts, which organize in blood islands in the yolk sac. The hemangioblasts differentiate into hematopoietic and angioblastic cells. Subsequently, the hematopoietic line will generate blood cells, whereas the angioblastic cells will give rise to vascular endothelial cells (ECs). In response to specific molecular and hemodynamic stimuli, ECs will acquire either arterial or venous identity. Recruitment towards the endothelial tubes and subsequent differentiation of pericyte and/or vascular smooth muscle cells (vSMCs) takes place and the mature vessel is formed. The Notch signaling pathway is required for determining the arterial program of both endothelial and smooth muscle cells; however, it is simultaneously involved in the generation of hematopoietic stem cells (HSCs), which will give rise to hematopoietic cells. Notch signaling also regulates the function of endothelial progenitor cells (EPCs), which are bone-marrow-derived cells able to differentiate into ECs and which could be considered the adult correlate of the angioblast. In addition, Notch signaling has been reported to control sprouting angiogenesis during blood vessels formation in the adult. In this paper we discuss the physiological role of Notch in vascular development, providing an overview on the involvement of Notch in vascular biology from hematopoietic stem cell to adaptive neovascularization in the adult. PMID:22550518

Caolo, Vincenza; Molin, Daniel G. M.; Post, Mark J.

2012-01-01

259

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

260

Localization of calcium stimulated adenosine triphosphatase activity in blood vessels of the skeleton  

NASA Technical Reports Server (NTRS)

Alkaline phosphatase is an enzyme found in bone forming cells which decreases in certain bones as a result of hypogravity or non-weight bearing. This enzyme can also hydrolyze adenosine triphosphate. Therefore, an effort was made to localize calcium-stimulated ATPase by cytochemistry to determine whether altered bone cell activity might be related to changing calcium levels which occur during hypogravity. The results indicate that Ca(++)-ATPase is largely found along the endothelium and basal lamina of blood vessels, and not found in bone forming cells. This suggests that calcium regulation in the vicinity of bone formation may be modulated by the vasculature of the area.

Doty, S. B.

1985-01-01

261

Recursive Algorithm for Blood Vessel Detection in Eye Fundus Images: Preliminary Results  

Microsoft Academic Search

\\u000a The eye fundus is the part of human body, where microvasculature can be observed directly. The vascular changes in the retina\\u000a are useful for diagnosing complications of diabetes, atherosclerosis, and hypertension. A lot of efforts are dedicated to\\u000a automate the analysis of retinal images. Among the problems of computerized retinal analysis is detection of blood vessel\\u000a tree.\\u000a \\u000a \\u000a Most of the

M. Patašius; V. Marozas; D. Jegelevièius; A. Lukoševièius

262

Architecture of the subendothelial elastic fibers of small blood vessels and variations in vascular type and size.  

PubMed

Most blood vessels contain elastin that provides the vessels with the resilience and flexibility necessary to control hemodynamics. Pathophysiological hemodynamic changes affect the remodeling of elastic components, but little is known about their structural properties. The present study was designed to elucidate, in detail, the three-dimensional (3D) architecture of delicate elastic fibers in small vessels, and to reveal their architectural pattern in a rat model. The fine vascular elastic components were observed by a newly developed scanning electron microscopy technique using a formic acid digestion with vascular casts. This method successfully visualized the 3D architecture of elastic fibers in small blood vessels, even arterioles and venules. The subendothelial elastic fibers in such small vessels assemble into a sheet of meshwork running longitudinally, while larger vessels have a higher density of mesh and thicker mesh fibers. The quantitative analysis revealed that arterioles had a wider range of mesh density than venules; the ratio of density to vessel size was higher than that in venules. The new method was useful for evaluating the subendothelial elastic fibers of small vessels and for demonstrating differences in the architecture of different types of vessels. PMID:23453051

Shinaoka, Akira; Momota, Ryusuke; Shiratsuchi, Eri; Kosaka, Mitsuko; Kumagishi, Kanae; Nakahara, Ryuichi; Naito, Ichiro; Ohtsuka, Aiji

2013-04-01

263

A pitfall of the volume rendering method with 3D time-of-flight MRA: a case of a branching vessel at the aneurysm neck.  

PubMed

We present a case in which the origin of the branching vessel at the aneurysm neck was observed at the wrong place on the volume rendering method (VR) with 3D time-of-flight MRA (3D-TOF-MRA) with 3-Tesla MR system. In 3D-TOF-MRA, it is often difficult to observe the origin of the branching vessel, but it is unusual for it to be observed in the wrong place. In the planning of interventional treatment and surgical procedures, false recognition, as in the unique case in the present report, is a serious problem. Decisions based only on VR with 3D-TOF-MRA can be a cause of suboptimal selection in clinical treatment. PMID:23474964

Goto, Masami; Kunimatsu, Akira; Shojima, Masaaki; Abe, Osamu; Aoki, Shigeki; Hayashi, Naoto; Mori, Harushi; Ino, Kenji; Yano, Keiichi; Saito, Nobuhito; Ohtomo, Kuni

2013-03-25

264

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.

265

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

Microsoft Academic Search

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

Uffe Midtgård

1984-01-01

266

Msx genes define a population of mural cell precursors required for head blood vessel maturation.  

PubMed

Vessels are primarily formed from an inner endothelial layer that is secondarily covered by mural cells, namely vascular smooth muscle cells (VSMCs) in arteries and veins and pericytes in capillaries and veinules. We previously showed that, in the mouse embryo, Msx1(lacZ) and Msx2(lacZ) are expressed in mural cells and in a few endothelial cells. To unravel the role of Msx genes in vascular development, we have inactivated the two Msx genes specifically in mural cells by combining the Msx1(lacZ), Msx2(lox) and Sm22?-Cre alleles. Optical projection tomography demonstrated abnormal branching of the cephalic vessels in E11.5 mutant embryos. The carotid and vertebral arteries showed an increase in caliber that was related to reduced vascular smooth muscle coverage. Taking advantage of a newly constructed Msx1(CreERT2) allele, we demonstrated by lineage tracing that the primary defect lies in a population of VSMC precursors. The abnormal phenotype that ensues is a consequence of impaired BMP signaling in the VSMC precursors that leads to downregulation of the metalloprotease 2 (Mmp2) and Mmp9 genes, which are essential for cell migration and integration into the mural layer. Improper coverage by VSMCs secondarily leads to incomplete maturation of the endothelial layer. Our results demonstrate that both Msx1 and Msx2 are required for the recruitment of a population of neural crest-derived VSMCs. PMID:21693521

Lopes, Miguel; Goupille, Olivier; Saint Cloment, Cécile; Lallemand, Yvan; Cumano, Ana; Robert, Benoît

2011-07-01

267

A numerical analysis on the curved bileaflet mechanical heart valve (mhv): leaflet motion and blood flow in an elastic blood vessel  

Microsoft Academic Search

In blood flow passing through the mechanical heart valve (MHV) and elastic blood vessel, hemolysis and platelet activation\\u000a causing thrombus formation can be seen owing to the shear stress in the blood. Also, fracture and deformation of leaflets\\u000a can be observed depending on the shape and material properties of the leaflets which is opened and closed in a cycle. Hence,

Jin Seok Bang; Choeng Ryul Choi; Chang Nyung Kim

2005-01-01

268

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

NASA Astrophysics Data System (ADS)

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

Zhang, Minghui; Brazel, Christopher

2011-11-01

269

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

270

Isolation of blood-vessel-derived multipotent precursors from human skeletal muscle.  

PubMed

Since the discovery of mesenchymal stem/stromal cells (MSCs), the native identity and localization of MSCs have been obscured by their retrospective isolation in culture. Recently, using fluorescence-activated cell sorting (FACS), we and other researchers prospectively identified and purified three subpopulations of multipotent precursor cells associated with the vasculature of human skeletal muscle. These three cell populations: myogenic endothelial cells (MECs), pericytes (PCs), and adventitial cells (ACs), are localized respectively to the three structural layers of blood vessels: intima, media, and adventitia. All of these human blood-vessel-derived stem cell (hBVSC) populations not only express classic MSC markers but also possess mesodermal developmental potentials similar to typical MSCs. Previously, MECs, PCs, and ACs have been isolated through distinct protocols and subsequently characterized in separate studies. The current isolation protocol, through modifications to the isolation process and adjustments in the selective cell surface markers, allows us to simultaneously purify all three hBVSC subpopulations by FACS from a single human muscle biopsy. This new method will not only streamline the isolation of multiple BVSC subpopulations but also facilitate future clinical applications of hBVSCs for distinct therapeutic purposes. PMID:25177794

Chen, William C W; Saparov, Arman; Corselli, Mirko; Crisan, Mihaela; Zheng, Bo; Péault, Bruno; Huard, Johnny

2014-01-01

271

Blood vessel density in de novo formed adipose tissue is decreased upon overexpression of TIMP-1.  

PubMed

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a role in the development of obesity by contributing to adipogenesis, angiogenesis, and extracellular matrix degradation. We have evaluated a potential functional role of TIMP-1, which inhibits most MMPs, in in vivo adipogenesis. Therefore, human (h) TIMP-1 was overexpressed by injection in the tail vein of NUDE mice of an adenoviral vector 3 days before injection of 3T3-F442A preadipocytes in the back. After 4 weeks of high-fat diet, the de novo formed fat was analyzed. Overexpression of hTIMP-1 had no effect on de novo formed fat pad mass. However, the blood vessel density of the fat pads from mice overexpressing hTIMP-1 was significantly lower than in controls (587 +/- 11 mm(-2) vs. 806 +/- 20 mm(-2), P < 0.0001) whereas the adipocytes were somewhat larger (1,477 +/- 44 microm(2) vs. 1,285 +/- 32 microm(2), P = 0.03). Thus, in vivo hTIMP-1 overexpression did not significantly affect the extent of de novo adipose tissue formation, but was associated with significantly lower blood vessel density. PMID:19730423

Scroyen, Ilse; Jacobs, Frank; Cosemans, Leentje; De Geest, Bart; Lijnen, Henri R

2010-03-01

272

Three Dimensional Endoscopic Image of a Blood Vessel Using High Frequency Ultrasound  

NASA Astrophysics Data System (ADS)

This paper describes a high frequency ultrasound (US) imaging system for observation of small tissues and a virtual endoscopic image of a blood vessel. This system consists of a US probe with a central frequency of 32 MHz, a microscope table designed to collect some slices of US brightness mode (B-mode) images, a transmitter containing control logic and a receiver circuit and a personal computer (PC) with an analog to digital (AD) converter. First, US B-mode images with high spatial resolution were obtained by shifting a measurement plane at a constant step of 0.075 mm. Second, three-dimensional (3-D) image reconstruction was performed with linear interpolation and a volume rendering technique. Finally, the point of view of the 3-D image was set in the human body and a virtual endoscopic image was presented. The experimental results present a blood vessel as if an ultrasound probe were inserted in it and reveal the anatomical structure under skin.

Oshiro, Osamu; Kamada, Kumi; Chihara, Kunihiro; Secomski, Wojciech; Nowicki, Andrzej

2000-05-01

273

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

274

A Shape-Directed Scaling Method for Fundus Image with Maintenance to Blood-Vessel Shapes and Color Reality  

NASA Astrophysics Data System (ADS)

When digitized fundus images are used in medicine, important information for clinicians' diagnosis should be maintained well after scaling. Conventional scaling methods select the interpolation kernel based on Shannon's sampling theorem which is only appropriate for band-limited signals and usually generate image with jaggy noise or blurred blood-vessel shapes that the tortuosity and diameter change of blood vessels which are important information to clinicians' diagnosis can not be maintained clearly. To solve these problems, we select the quadratic Fluency sampling function as the interpolation kernel to maintain the color reality of fundus image based on the Fluency information theory. Scaling is then realized by interpolation directed to the blood-vessel shape map of required resolution which is generated from two kinds of Fluency sampling functions. These two kinds of Fluency sampling functions are precedingly utilized to approximate shapes of blood vessels on the original fundus image according to the suggestion of specialists in fundus field. Resulting images by the proposed method show good shape maintenance of blood vessels and have a better quantitative evaluation than the generally recognized best conventional method.

Sheng, Kai; Kameyama, Keisuke; Toraichi, Kazuo; Mitamura, Yoshinori; Katagishi, Kazuki; Morooka, Yasuo; Ohmiya, Yasuhiro

275

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

PubMed

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

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

2014-11-01

276

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

277

Imaging of blood vessels with CCD-camera based three-dimensional photoacoustic tomography  

NASA Astrophysics Data System (ADS)

An optical phase contrast full field detection setup in combination with a CCD-camera is presented to record acoustic fields for real-time projection and fast three-dimensional imaging. When recording projection images of the wave pattern around the imaging object, the three-dimensional photoacoustic imaging problem is reduced to a set of two-dimensional reconstructions and the measurement setup requires only a single axis of rotation. Using a 10 Hz pulse laser system for photoacoustic excitation a three dimensional image can be obtained in less than 1 min. The sensitivity and resolution of the detection system was estimated experimentally with 5 kPa mm and 75?m, respectively. Experiments on biological samples show the applicability of this technique for the imaging of blood vessel distributions.

Nuster, Robert; Slezak, Paul; Paltauf, Guenther

2014-03-01

278

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

PubMed

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

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

2007-08-01

279

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, Severine A.; Evain-Brion, Daniele

2014-01-01

280

Ultrastructural changes in blood vessels in epidermal growth factor treated experimental cutaneous wound model.  

PubMed

This study investigates the impact of epidermal growth factor (EGF) on blood vessels, specifically on the development of intussusceptive angiogenesis in cutaneous wound healing. Excisional wounds were formed on both sides of the medulla spinalis in dorsal location of the rats. The control and EGF-treated groups were divided into two groups with respect to sacrifice day: 5 d and 7 d. EGF was topically applied to the EGF-treated group once a day. The wound tissue was removed from rats, embedded in araldite and paraffin, and then examined under transmission electron and light microscopes. The ultrastructural signs of intussusceptive angiogenesis, such as intraluminal protrusion of endothelial cells and formation of the contact zone of opposite endothelial cells, were observed in the wound. Our statistical analyses, based on light microscopy observations, also confirm that EGF treatment induces intussusceptive angiogenesis. Moreover, we found that induction of EGF impact on intussusceptive angiogenesis is higher on the 7th day of treatment than on the 5th day. This implies that the duration of EGF treatment is important. This research clarifies the effects of EGF on the vessels and proves that EGF induces intussusceptive angiogenesis, being a newer model with respect to sprouting type. PMID:24011796

K?l?çaslan, Seda M Sar?; Cevher, Sule Co?kun; Peker, Emine G Güleç

2013-11-01

281

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

282

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

PubMed

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

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

2013-11-01

283

Plasma 5-hydroxytryptamine constricts equine digital blood vessels in vitro: implications for pathogenesis of acute laminitis.  

PubMed

Cumulative concentration response curves to 5-hydroxytryptamine (5-HT; 10(-10)-10(-4) mol/l) were constructed using isolated rings of equine digital, facial, tail and coronary arteries (endothelium intact). 5-HT was 17.7 and 41 times more potent as a vasoconstrictor of digital arteries than facial and tail arteries respectively. Removal of the endothelium increased the vasoconstrictor potency of 5-HT in the facial artery by 3.7-fold (P<0.05) but did not alter the sensitivity of digital arteries to 5-HT. Coronary arteries failed to contract to 5-HT. Coronary arteries pre-contracted with U44069 showed concentration dependent relaxation to 5-HT, a response which was partially dependent on the presence of the endothelium. No vasorelaxant effects were found in the digital or facial arteries. The concentration of 5-HT in platelet poor and platelet rich equine plasma was found to be 6.70+/-1.1 x 10(-8) mol/l and 1.77+/-0.36 x 10(-6) mol/l (mean +/-s.e.) respectively by high performance liquid chromatography (HPLC). Plasma which contained no detectable platelets had a 5-HT concentration of 1.12+/-0.48 x 10(-8) mol/l. Isolated digital arteries constricted when exposed to dilutions of platelet poor and platelet depleted equine plasma. These plasma induced contractions were almost completely inhibited by 5-HT receptor antagonists, ketanserin and methiothepin. The change in isometric tension in rings of equine digital artery in vitro was therefore used as a bioassay for plasma 5-HT and the results obtained by this method showed an excellent correlation (r2 = 97.2%, P<0.001) with the concentration estimated by HPLC. Circulating free concentrations of 5-HT in normal horses may be sufficient to constrict digital blood vessels partially in vivo but are well below the threshold for contraction of other peripheral blood vessels examined. PMID:9535068

Bailey, S R; Elliott, J

1998-03-01

284

Different biomarkers in non-small cell lung cancer in blood vessel invasion.  

PubMed

In clinical settings, lung cancer is divided into small cell lung cancer and non-small cell lung cancer, and chemotherapy is depended on the difference. Using the same chemotherapy treatment, different effects and prognosis can be seen among squamous-cell carcinoma and adenocarcinoma. These differences indicate that there may be various methods of invasion and immunity between squamous-cell carcinoma and adenocarcinoma. Blood vessel invasion and tumor immune escape play very important roles in the progression and metastasis of cancer, and CD105 and integrins are novel therapeutic targets. We assessed the possible association of CD105 expression and integrins with TNM classification in patients with two types of NSCLC. A total of 72 patients with resected Non-Small Cell Lung Cancer (NSCLC) were reviewed retrospectively. Integrin ?1, ?2, ?3, and ?5?1 are assayed by immunofluorescence and integrin ?5?1 using immunoblot. Intratumoral microvessel density was determined with an anti-CD34 mAb and an anti-CD105 mAb. Invasive ability was assayed with MMP2 and MMP9 using immunofluorescence. The expressions of all integrins, CD105, and CD34 are low in the normal lung tissue and highly expressed in the cancer niche compared to the adjacent tissues. CD105 is highly expressed in the adenocarcinoma niche compared to the squamous-cell carcinoma in NSCLC. The expressions of both MMP2 and MMP9 are low in the normal lung tissue and highly expressed in adjacent tissues. This study shows that blood vessel invasion appears to be an independent negative prognosticator in surgically managed types of NSCLC. However, adequately designed large prospective studies are warranted to confirm the present findings. PMID:24801771

Zhang, Chunyu; Liu, Ying; Guo, Shengnan; Zhang, Jie

2014-11-01

285

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

PubMed Central

Several strategies have been used to generate transgenic birds. The most successful method so far has been the injection of lentiviral vectors into the subgerminal cavity of a newly laid egg. We report here a new, easy and effective way to produce transgenic quails through direct injection of a lentiviral vector, containing an enhanced-green fluorescent protein (eGFP) transgene, into the blood vessels of quail embryos at Hamburger-Hamilton stage 13–15 (HH13–15). A total of 80 embryos were injected and 48 G0 chimeras (60%) were hatched. Most injected embryo organs and tissues of hatched quails were positive for eGFP. In five out of 21 mature G0 male quails, the semen was eGFP-positive, as detected by polymerase chain reaction (PCR), indicating transgenic germ line chimeras. Testcross and genetic analyses revealed that the G0 quail produced transgenic G1 offspring; of 46 G1 hatchlings, 6 were transgenic (6/46, 13.0%). We also compared this new method with the conventional transgenesis using stage X subgerminal cavity injection. Total 240 quail embryos were injected by subgerminal cavity injection, of which 34 (14.1%) were hatched, significantly lower than the new method. From these hatched quails semen samples were collected from 19 sexually matured males and tested for the transgene by PCR. The transgene was present in three G0 male quails and only 4/236 G1 offspring (1.7%) were transgenic. In conclusion, we developed a novel bird transgenic method by injection of lentiviral vector into embryonic blood vessel at HH 13–15 stage, which result in significant higher transgenic efficiency than the conventional subgerminal cavity injection. PMID:23251391

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

2012-01-01

286

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

PubMed Central

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

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

2010-01-01

287

Human Blood Vessel-Derived 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. EPC–derived 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

288

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 21 days prior to imaging. On the imaging day, [68Ga]GaCl3 was injected and the mice were imaged from 45 to 90 min 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

289

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

Microsoft Academic Search

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

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

2001-01-01

290

Lasers in Surgery and Medicine 42:105112 (2010) Long-Term Blood Vessel Removal With Combined Laser  

E-print Network

Lasers in Surgery and Medicine 42:105�112 (2010) Long-Term Blood Vessel Removal With Combined Laser and Topical Rapamycin Antiangiogenic Therapy: Implications for Effective Port Wine Stain Treatment Wangcun Jia and Objectives: Complete blanching of port wine stain (PWS) birthmarks after laser therapy is rarely achieved

Choi, Bernard

291

Possible application of spectral analysis techniques on ultrasonic echo-traces improved for studying changes in blood vessel walls  

Microsoft Academic Search

Parametric algorithms previously developed by authors for spectral evaluation of biological multi-echo waveforms are adapted and improved here in order to achieve a more elevated frequency resolution. These results permit to undertake viability studies around the possible application of a new auto-regressive spectral technique to estimate physical properties like wall thickness changes in blood vessels, with accuracy enough. These difficult

I. Bazan; C. Negreira; A. Ramos; H. Calas; T. E Gomez; A. Ramirez; J. M. de la Rosa; F. J. Gallegos

2012-01-01

292

Measurement of meningeal blood vessel diameter in vivo with a plug-in for ImageJ  

Microsoft Academic Search

Changes in blood vessel diameter can be measured manually, but this is time-consuming and often impractical. For automatic measurement commercial solutions are available, but the proprietary algorithms and their potential shortcomings are not known to the user. We present an approach with a CCD camera for image acquisition combined with free and open source ImageJ software for offline analysis. A

Michael J. M. Fischer; Sae Uchida; Karl Messlinger

2010-01-01

293

Nonparenchymal cells cultivated from explants of fibrotic liver resemble endothelial and smooth muscle cells from blood vessel walls  

Microsoft Academic Search

Tissue specimens from human fibrotic liver obtained by needle biopsy were cultured. Two cell types emerged from the tissue explants. From their morphology and biosynthetic products they resembled smooth muscle cells and endothelial cells from blood vessel walls. In the endothelial cells, factor VIII-associated protein was demonstrated by indirect immunofluorescence. Synthesis of collagen types I and III, basement membrane collagen

B. Voss; J. Rauterberg; G. Pott; U. Brehmer; S. Allam; R. Lehmann; D. B. von Bassewitz

2009-01-01

294

Postpartum hemoperitoneum due to rupture of a blood vessel on a uterine pseudo tumor: a case report  

PubMed Central

We are reporting a case of hemoperitoneum followed by early post partum collapse due to bleeding from a ruptured vessel on the surface of an undiagnosed uterine pseudo tumor. There are literature reports of spontaneous hemoperitoneum from bleeding of superficial vessels over lying myomas during pregnancy but a case of rupture of a blood vessel on a uterine pseudo tumor leading to isolated hemoperitoneum in the immediate postpartum period is a rare event. We are presenting the literature review and some aspects of the management of this case. The importance of having a high index of suspicion in cases of hemoperitoeum occurring immediately after delivery especially in a low income setting where radiologic imaging techniques like magnetic resonance imaging (MRI); which is the most sensitive diagnostic tool in cases of ruptured vessels are rare is highlighted. PMID:24672628

Ekane, Gregory Halle; Tebeu, Pierre Marie; Obinchemti, Thomas Egbe; Njamen, Theophile Nana; Nguefack, Charlotte Tchente; Kamgaing, Jacques Tsingaing; Priso, Eugene Belley

2013-01-01

295

Localization and Quantification of Platelet-Rich Thrombi in Large Blood Vessels using Near-Infrared Fluorescence Imaging  

PubMed Central

Background Imaging of thrombus formation in vivo has been limited by the inability to directly visualize and measure thrombi in large blood vessels in real-time. Near-infrared light, with its superior tissue penetration and reduced scatter, could potentially solve this problem. Methods Platelets were labeled with the near-infrared fluorophore IR-786. Optimal total fluorescence yield occurred at 6 attomoles of IR-786 per platelet. IR-786-labeled platelets were tested for their ability to detect thrombus formation in large animal model systems relevant to common human vascular procedures. Results Invisible near-infrared light did not distort the surgical field in any way, and even after optimization of per platelet fluorescent yield, platelets remained fully functional. Intravenous infusion of just 3.6 × 1010 labeled platelets into a 35 kg Yorkshire pig permitted thrombus visualization, with a signal to background ratio ? 2, for at least two hours in coronary, carotid, and femoral vessels. Platelet-rich, actively growing clots were monitored in real-time, and quantified with respect to size and kinetics after injury to vessels, cutaneous incisions, intravascular stent insertion, or introduction of embolic coils. Similarly, formed clots were monitored in real-time during thrombolysis with streptokinase and heparin. Vessel patency was assessed independently using a second near-infrared fluorescent blood pool agent. Conclusions IR-786-labeled platelets provide sensitive, specific, and real-time visualization of thrombi in thick-walled blood vessels. In addition to immediate application in cardiac, transplant, and vascular surgery, the mechanisms underlying thrombus formation in large blood vessels can now be investigated. PMID:17179017

Flaumenhaft, Robert; Tanaka, Eiichi; Graham, Gwenda J.; De Grand, Alec M.; Laurence, Rita G.; Hoshino, Kozo; Hajjar, Roger J.; Frangioni, John V.

2008-01-01

296

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

297

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

298

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.; Dró?d?, A.

2014-08-01

299

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

300

Fusing VE-Cadherin to ?-Catenin Impairs Fetal Liver Hematopoiesis and Lymph but Not Blood Vessel Formation  

PubMed Central

We have recently shown that genetic replacement of VE-cadherin by a VE-cadherin–?-catenin fusion construct strongly impairs opening of endothelial cell contacts during leukocyte extravasation and induction of vascular permeability in adult mice. Here we show that this mutation leads to lethality at midgestation on a clean C57BL/6 background. Investigating the reasons for embryonic lethality, we observed a lack of fetal liver hematopoiesis and severe lymphedema but no detectable defects in blood vessel formation and remodeling. As for the hematopoiesis defect, VE-cadherin–?-catenin affected neither the generation of hematopoietic stem and progenitor cells (HSPCs) from hemogenic endothelium nor their differentiation into multiple hematopoietic lineages. Instead, HSPCs accumulated in the fetal circulation, suggesting that their entry into the fetal liver was blocked. Edema formation was caused by disturbed lymphatic vessel development. Lymphatic progenitor cells of VE-cadherin–?-catenin-expressing embryos were able to leave the cardinal vein and migrate to the site of the first lymphatic vessel formation, yet subsequently, these cells failed to form large lumenized lymphatic vessels. Thus, stabilizing endothelial cell contacts by a covalent link between VE-cadherin and ?-catenin affects recruitment of hematopoietic progenitors into the fetal liver and the development of lymph but not blood vessels. PMID:24567373

Dartsch, Nina; Schulte, Dörte; Hägerling, René

2014-01-01

301

Gcsf-Chr19 promotes neutrophil migration to damaged tissue through blood vessels in zebrafish.  

PubMed

G-CSF is an essential cytokine that regulates proliferation and differentiation of granulocytes from hematopoietic stem and progenitor cells. In mammals G-CSF has been identified as a key factor that promotes the release of neutrophils from the bone marrow into the blood circulation. In silico analysis indicates that zebrafish has two gcsf genes, gcsf-chr12 in chromosome 12 and gcsf-chr19 in chromosome 19. Gcsf-Chr12 participates in emergency myelopoiesis, but, in contrast to its mammalian orthologue, is not involved in neutrophil migration toward damaged tissue. In turn, the function of Gcsf-Chr19 has not been examined yet. In this study, we analyzed the role of Gcsf-Chr19 in regulating neutrophil migration toward the wound. Our results indicated that during the first h after caudal fin transection, neutrophils migrate from the hematopoietic tissue toward the injury, using the extracellular matrix as a substrate. Later, between 3 and 4 h postdamage, the recruitment mainly occurs through the bloodstream, and only a few neutrophils still use the extracellular matrix to migrate. During this process, the transcriptional levels of gcsf-chr19 are considerably increased, reaching a peak 1 h postdamage. The knockdown of Gcsf-chr19 indicated that the percentage of neutrophils that reach the wound decreased after the first h postinjury, suggesting that the knockdown specifically affects neutrophils that travel to the wound through blood vessels. Together, our data provide novel information about the regulation of neutrophil migration in zebrafish, positioning Gcsf-Chr19 as a key signal during the course of an inflammatory process triggered by severe damage. PMID:24890728

Galdames, Jorge A; Zuñiga-Traslaviña, Constanza; Reyes, Ariel E; Feijóo, Carmen G

2014-07-01

302

Immune Reactivity in Psoriatic Munro-Saboureau Microabscesses, Stratum Corneum and Blood Vessels  

PubMed Central

Background: A characteristic feature of early active psoriatic lesions is the intraepidermal penetration of neutrophils, with attendant formation of Munro-Saboureau microabscesses. Previous immunofluorescence studies have shown reactivity of in vivo binding of stratum corneum antibodies (SCAs) within the Munro-Saboreau microabscesses in cases of psoriasis. Aims: In our study, we aimed to investigate any correlation between the SCAs and the Munro-Saboureau microabscesses. Materials and Methods: We investigated 50 archival biopsies of psoriasis with Munro-Saboureau microabscesses, and attempted to confirm antibody colocalization within these microabcesses via immunohistochemistry staining. As controls, we utilized 50 skin biopsies from healthy patients undergoing esthetic plastic surgery procedures. Results: Within the Munro-Saboureau microabscesses, the following markers were statistically significantly positive relative to controls: CD1a, CD8, CD23, cyclooxygenase-2, myeloid histoid antigen, albumin, fibrinogen, kappa, lambda, von Willebrand factor, IgG, IgM, IgD, complement/C3c, C3d, myeloperoxidase, and carcinoembryonic antigen (P < 0.05). Autoreactivity to blood vessels was also detected, with multiple immunoglobulins and complement factors. Conclusions: We document important correlations between the Munro-Saboureau microabscesses, SCAs, and other immunoreactants. PMID:22754876

Abreu-Velez, Ana Maria; Googe, Paul B; Howard, Michael S

2012-01-01

303

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

304

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

305

Evaluation of local density enhancement of microcapsules in artificial blood vessel during exposure to focused ultrasound  

NASA Astrophysics Data System (ADS)

We have proposed a physical DDS (Drug Delivery System) which makes use of microcapsules of ?m size, which may contain a specified drug and also are easily affected by ultrasound exposure near their resonant frequency, to release various kinds of medications. These capsules are easily detected and actuated by ultrasound. However, because of the diffusion of capsules after injection into human body, it was difficult to enhance the efficiency of drug delivery. Thus we have considered a method for controlling the density of capsules in flow which uses acoustic radiation force, which moves the capsules to balance flow resistance. We have experimented with trapping microcapsules or microbubbles in flow of an artificial blood vessel. We have evaluated the effect of radiation force by measuring the trapped area of capsules or bubbles for various frequencies, sound pressures, and exposure times of sinusoidal ultrasound. The trapped area of capsules or bubbles increased with sound pressure and exposure time, and decreased with frequency. From those results, we have derived optimal conditions for trapping the capsules or bubbles.

Nakamoto, Ryusuke; Masuda, Kohji; Watarai, Nobuyuki; Taguchi, Yuto; Kato, Toshikazu; Yoshinaga, Takashi; Miyamoto, Yoshitaka; Chiba, Toshio

2011-09-01

306

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

PubMed Central

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

Jimenez Rios, Jorge L.; Rabin, Yoed

2008-01-01

307

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

NASA Astrophysics Data System (ADS)

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

Baba, J. S.; Akl, T. J.; Coté, G. L.; Wilson, M. A.; Ericson, M. N.

2011-03-01

308

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

309

LWR Pressure Vessel Surveillance Dosimetry Improvement Program for NRC (Nuclear Regulatory Commission) Materials Engineering Branch: 1985 summary annual report  

Microsoft Academic Search

The objective of this program is to make measurements in neutron fields (''Benchmark'' and reactor ''Test Surveillance Regions'') for the subsequent validation\\/calibration of available state-of-the-art physics-dosimetry-metallurgy, damage correlation, and associated reactor analysis procedures and data. These procedures and data are in turn used for predicting the integrated effects of neutron exposure to Light Water Reactor (LWR) Pressure Vessel (PV) and

McElroy

1988-01-01

310

Integrin-?5?1 is not required for mural cell functions during development of blood vessels but is required for lymphatic-blood vessel separation and lymphovenous valve formation.  

PubMed

Integrin ?5?1 is essential for vascular development but it remains unclear precisely where and how it functions. Here, we report that deletion of the gene encoding the integrin-?5 subunit (Itga5) using the Pdgfrb-Cre transgenic mouse line, leads to oedema, haemorrhage and increased levels of embryonic lethality. Unexpectedly, these defects were not caused by loss of ?5 from Pdgfrb-Cre expressing mural cells (pericytes and vascular smooth muscle cells), which wrap around the endothelium and stabilise blood vessels, nor by defects in the heart or great vessels, but were due to abnormal development of the lymphatic vasculature. Reminiscent of the pathologies seen in the human lymphatic malformation, fetal cystic hygroma, ?5 mutants display defects both in the separation of their blood and lymphatic vasculature and in the formation of the lymphovenous valves. As a consequence, ?5-deficient mice develop dilated, blood-filled lymphatic vessels and lymphatic capillaries that are ectopically covered with smooth muscle cells. Analysis of the expression of Pdgfrb during lymphatic development suggests that these defects probably arise from loss of ?5?1 integrin in subsets of specialised Prox1(+)Pdgfrb(+) venous endothelial cells that are essential for the separation of the jugular lymph sac from the cardinal vein and formation of the lymphovenous valve leaflets. PMID:24858485

Turner, Christopher J; Badu-Nkansah, Kwabena; Crowley, Denise; van der Flier, Arjan; Hynes, Richard O

2014-08-15

311

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

312

Study on the Dynamic Compound Structure Composed of Mast Cells, Blood Vessels, and Nerves in Rat Acupoint  

PubMed Central

Background. Circulation system, immunity system, and nervous system have a close relationship with meridian phenomen. However, there is still lack of the results of dynamic changes of these structures in acupoint. The aim of this study is to explore the interrelationship by composite staining techniques. Methodology/Principal Findings. Twenty rats were separated into electroacupuncture group (EA) and control group (Con) randomly. In EA group, the Zusanli and Weishu were stimulated with the 0.1?mA for 25?min. The tissue of these acupoints was double-stained with acetylcholinesterase and Toluidine blue. The compound structure of mast cells, nervous fibers, and mast cells in the acupoint was observed. Conclusions/Significance. The blood vessels, mast cells and acetylcholinesterase responded nerves were clearly observed in acupoint tissues. EA can result in the mast cell recruitment and migration along the blood vessels and nervous bundle, which conformed the dynamic compound structure and played important roles in acupuncture. PMID:23878591

Mingfu, Luo; Xiaotong, Dong; Xiaojing, Song; Jin, Jiang; Jinling, Zhann; Ying, Han

2013-01-01

313

Novel method for early signs of clinical shock detection by monitoring blood capillary/vessel spatial pattern.  

PubMed

The ability to monitor capillary/vessel spatial patterns and local blood volume fractions is critical in clinical shock detection and its prevention in Intensive Care Units (ICU). Although the causes of shock might be different, the basic abnormalities in pathophysiological changes are the same. To detect these changes, we have developed a novel method based on both spectrally and spatially resolved diffuse reflectance spectra. The preliminary study has shown that this method can monitor the spatial distribution of capillary/vessel spatial patterns through local blood volume fractions of reduced hemoglobin and oxyhemoglobin. This method can be used as a real-time and non-invasive tool for the monitoring of shock development and feedback on the therapeutic intervention. PMID:23843326

Kanawade, Rajesh; Klämpfl, Florian; Riemann, Max; Knipfer, Christian; Tangermann-Gerk, Katja; Schmidt, Michael; Stelzle, Florian

2014-10-01

314

Blood levels of branched-chain alpha-keto acids in uremia: effect of an oral glucose tolerance test.  

PubMed

The effect of an oral glucose tolerance test (oGTT) on serum levels of branched-chain keto acids (BCKA), i.e. alpha-keto-isocaproic acid (KICA), alpha-keto-isovaleric acid (KIVA) and alpha-keto-beta methyl-n-valeric acid (KMVA) as well as on serum insulin, C-peptide and blood glucose levels was determined in uremic patients and in healthy control subjects. In controls, blood levels of KICA, KMVA and KIVA declined significantly following oral administration of 100 glucose. In uremic patients no decline of KICA was observed. The fall of KMVA was diminished, while suppression of KIVA blood levels in response to the oGGT remained unimpaired. Although serum insulin and C-peptide levels in uremic patients were not significantly different from the controls before and throughout the oGTT, six out of eight displayed abnormal glucose tolerance. It is suggested that the response of blood BCKA levels to an oGTT is altered in uremia, an abnormality restricted primarily to KICA and possibly explained by insulin antagonism and/or by insufficient insulin secretion. PMID:7021997

Schauder, P; Matthaei, D; Henning, H V; Scheler, F; Langenbeck, U

1981-08-01

315

Development of Vascular Reactivity in Chickens: Responses of Mesenteric and Hind-Limb Blood Vessels to Norepinephrine and Acetylcholine  

Microsoft Academic Search

Mesenteric arteries and the hind-limb vasculature supplied by the sciatic artery were isolated from chickens 0–25 vity days after hatching and perfused with physiological saline. Mesenteric arteries gave only small responses to norepinephrine until the 2nd week after hatching when there was a striking increase in their reactivity. Hind-limb blood vessels were much more responsive to norepinephrine from the 1st

A. Knight; D. D. McGregor

1974-01-01

316

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

PubMed Central

Rationale Disruption of the circadian clock in mice produces vascular dysfunction as evidenced by impairments in endothelium-dependent signaling, vasomotion, and blood vessel remodeling. Although the altered function of endothelial NO synthase and the overproduction of reactive oxygen species are central to dysfunction of the endothelium, to date, the impact of the circadian clock on endothelial NO synthase coupling and vascular reactive oxygen species production is not known. Objective The goals of the present study were to determine whether deletion of a critical component of the circadian clock, Bmal1, can influence endothelial NO synthase coupling and reactive oxygen species levels in arteries from Bmal1-knockout (KO) mice. Methods and Results Endothelial function was reduced in aortae from Bmal1-KO mice and improved by scavenging reactive oxygen species with polyethylene glycol-superoxide dismutase and nonselectively inhibiting cyclooxygenase isoforms with indomethacin. Aortae from Bmal1-KO mice exhibited enhanced superoxide levels as determined by electron paramagnetic resonance spectroscopy and dihydroethidium fluorescence, an elevation that was abrogated by administration of nitro-L -arginine methyl ester. High-performance liquid chromatography analysis revealed a reduction in tetrahydrobiopterin and an increase in dihydrobiopterin levels in the lung and aorta of Bmal1-KO mice, whereas supplementation with tetrahydrobiopterin improved endothelial function in the circadian clock KO mice. Furthermore, levels of tetrahydrobiopterin, dihydrobiopterin, and the key enzymes that regulate biopterin bioavailability, GTP cyclohydrolase and dihydrofolate reductase exhibited a circadian expression pattern. Conclusions Having an established influence in the metabolic control of glucose and lipids, herein, we describe a novel role for the circadian clock in metabolism of biopterins, with a significant impact in the vasculature, to regulate coupling of endothelial NO synthase, production of superoxide, and maintenance of endothelial function. (Circ Res. 2012; 111:1157–1165.) PMID:22912383

Anea, Ciprian B.; Cheng, Bo; Sharma, Shruti; Kumar, Sanjiv; Caldwell, R. William; Yao, Lin; Ali, M. Irfan; Merloiu, Ana M.; Stepp, David W.; Black, Stephen M.; Fulton, David J.R.; Rudic, R. Daniel

2013-01-01

317

Anisotropic micro-sphere-based finite elasticity applied to blood vessel modelling  

NASA Astrophysics Data System (ADS)

A fully three-dimensional anisotropic elastic model for vascular tissue modelling is presented here. The underlying strain energy density function is assumed to additively decouple into volumetric and deviatoric contributions. A straightforward isotropic neo-Hooke-type law is used to model the deviatoric response of the ground substance, whereas a micro-structurally or rather micro-sphere-based approach will be employed to model the contribution and distribution of fibres within the biological tissue of interest. Anisotropy was introduced by means of the use of von Mises orientation distribution functions. Two different micro-mechanical approaches—a, say phenomenological, exponential ansatz, and a worm-like-chain-based formulation—are applied to the micro-fibres and illustratively compared. The passage from micro-structural contributions to the macroscopic response is obtained by a computational homogenisation scheme, namely numerical integration over the surface of the individual micro-spheres. The algorithmic treatment of this integration is discussed in detail for the anisotropic problem at hand, so that several cubatures of the micro-sphere are tested in order to optimise the accuracy at reasonable computational cost. Moreover, the introduced material parameters are identified from simple tension tests on human coronary arterial tissue for the two micro-mechanical models investigated. Both approaches are able to recapture the experimental data. Based on the identified sets of parameters, we first discuss a homogeneous deformation in simple shear to evaluate the models' response at the micro-structural level. Later on, an artery-like two-layered tube subjected to internal pressure is simulated by making use of a non-linear finite element setting. This enables to obtain the micro- and macroscopic responses in an inhomogeneous deformation problem, namely a blood vessel representative boundary value problem. The effect of residual stresses is additionally included in the model by means of a multiplicative decomposition of the deformation gradient tensor which turns out to crucially affect the simulation results.

Alastrué, V.; Martínez, M. A.; Doblaré, M.; Menzel, A.

2009-01-01

318

The pharmacology of nitric oxide in the peripheral nervous system of blood vessels.  

PubMed

Unanticipated, novel hypothesis on nitric oxide (NO) radical, an inorganic, labile, gaseous molecule, as a neurotransmitter first appeared in late 1989 and into the early 1990s, and solid evidences supporting this idea have been accumulated during the last decade of the 20th century. The discovery of nitrergic innervation of vascular smooth muscle has led to a new understanding of the neurogenic control of vascular function. Physiological roles of the nitrergic nerve in vascular smooth muscle include the dominant vasodilator control of cerebral and ocular arteries, the reciprocal regulation with the adrenergic vasoconstrictor nerve in other arteries and veins, and in the initiation and maintenance of penile erection in association with smooth muscle relaxation of the corpus cavernosum. The discovery of autonomic efferent nerves in which NO plays key roles as a neurotransmitter in blood vessels, the physiological roles of this nerve in the control of smooth muscle tone of the artery, vein, and corpus cavernosum, and pharmacological and pathological implications of neurogenic NO have been reviewed. This nerve is a postganglionic parasympathetic nerve. Mechanical responses to stimulation of the nerve, mainly mediated by NO, clearly differ from those to cholinergic nerve stimulation. The naming "nitrergic or nitroxidergic" is therefore proposed to avoid confusion of the term "cholinergic nerve", from which acetylcholine is released as a major neurotransmitter. By establishing functional roles of nitrergic, cholinergic, adrenergic, and other autonomic efferent nerves in the regulation of vascular tone and the interactions of these nerves in vivo, especially in humans, progress in the understanding of cardiovascular dysfunctions and the development of pharmacotherapeutic strategies would be expected in the future. PMID:12773630

Toda, Noboru; Okamura, Tomio

2003-06-01

319

Effect of rheological property on blood flow in vertebral artery branch  

NASA Astrophysics Data System (ADS)

Blocking of an artery is one of mechanisms for cerebral stroke development. If an important cerebral artery is occluded by any reason and if there is no sufficient collaterals, tissue ischemia occurs at brain tissues distal to the occluded artery, which is a well known clinical situation. However, in practice, ischemia or hypoperfusion has also been observed through the branches proximal to the occluded artery. The unexpected ``proximal ischemia'' is not yet known, from which patients could suffer serious complications. In the present study, two patient cases are presented to elucidate this phenomenon from the view point of fluid dynamics, especially with emphasis on the role of rheology in hemodynamics.

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

2011-11-01

320

Nestin(+) tissue-resident multipotent stem cells contribute to tumor progression by differentiating into pericytes and smooth muscle cells resulting in blood vessel remodeling.  

PubMed

Tumor vessels with resistance to anti-angiogenic therapy are characterized by the normalization of the vascular structures through integration of mature pericytes and smooth muscle cells (SMC) into the vessel wall, a process termed vessel stabilization. Unfortunately, stabilization-associated vascular remodeling can result in reduced sensitivity to subsequent anti-angiogenic therapy. We show here that blockade of VEGF by bevacizumab induces stabilization of angiogenic tumor blood vessels in human tumor specimen by recruiting Nestin-positive cells, whereas mature vessels down-regulated Nestin-expression. Using xenograft tumors growing on bone-marrow (BM) chimera of C57Bl/6 wildtype and Nestin-GFP transgenic mice, we show for first time that Nestin(+) cells inducing the maturation of tumor vessels do not originate from the BM but presumably reside within the adventitia of adult blood vessels. Complementary ex vivo experiments using explants of murine aortas revealed that Nestin(+) multipotent stem cells (MPSCs) are mobilized from their niche and differentiated into pericytes and SMC through the influence of tumor-cell-secreted factors. We conclude that tissue-resident Nestin(+) cells are more relevant than BM-derived cells for vessel stabilization and therefore have to be considered in future strategies for anti-angiogenic therapy. The identification of proteins mediating recruitment or differentiation of local Nestin(+) cells with potential stem cell character to angiogenic blood vessels may allow the definition of new therapeutic targets to reduce tumor resistance against anti-angiogenic drugs. PMID:25019063

Klein, Diana; Meissner, Nicole; Kleff, Veronika; Jastrow, Holger; Yamaguchi, Masahiro; Ergün, Süleyman; Jendrossek, Verena

2014-01-01

321

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.

322

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

323

Measurement of meningeal blood vessel diameter in vivo with a plug-in for ImageJ.  

PubMed

Changes in blood vessel diameter can be measured manually, but this is time-consuming and often impractical. For automatic measurement commercial solutions are available, but the proprietary algorithms and their potential shortcomings are not known to the user. We present an approach with a CCD camera for image acquisition combined with free and open source ImageJ software for offline analysis. A subtraction image allows for the evaluation of the diameter changes throughout the field of view. A full width at half-maximum algorithm plug-in was written to measure the vessel diameter. For a given line across a vessel, the results of five measurements with parallel shifts throughout an image stack are copied to the clipboard. For validation of this method an established in vivo model was used, namely vascular changes in the rat dura mater, reflecting the activity of the afferent neurons. Vasoconstriction of the meningeal arterioles induced by local electrical stimulation of the dura was inhibited by intravenous administration of the adrenoceptor antagonist phentolamine and amplified by the CGRP receptor antagonist olcegepant. The described methods allow the user to quickly evaluate vessel diameter changes in the whole acquired field at any selected position. PMID:20406650

Fischer, Michael J M; Uchida, Sae; Messlinger, Karl

2010-09-01

324

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; Bernabo, Nicola; Di Giacinto, Oriana; Mattioli, Mauro; Barboni, Barbara

2014-01-01

325

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

326

Whole-Mount Confocal Microscopy for Vascular Branching Morphogenesis  

PubMed Central

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

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

2014-01-01

327

The Arteriovenous Malformation Associated with Major Arterial Occlusion and Moyamoya Vessels: a Cerebral Blood Flow Study  

PubMed Central

Summary We report 2 patients with arteriovenous malformation (AVM) associated with complete occlusion of the unilateral middle cerebral artery and moyamoya vessels. Xenon CT CBF study demonstrated diffusely decreased CMF in unilateral or bilateral hemispheres with multiple areas of decreased vascular reserve. A significant reduction of AVM size was seen in one patient who received radiosurgery with marked CBF improvement. PMID:20667197

Numaguchi, Y.; Wang, H.Z.; Stern, A.; Alleyne, C.H.; Lunsford, L.D.

2000-01-01

328

Blood vessel detection in navigated ultrasound: An assistance system for liver resections  

Microsoft Academic Search

Open liver resection is a difficult and dangerous surgical operation, which requires a lot of experience and knowledge of the patient's anatomy. Ultrasound, as a predominantly used interoperative image modality, helps the surgeon guiding the resection process. Until present time there is no convincing solution to reduce the risk of accidental injure of liver vessels or to guide the targeting

Nikolas Doerfler; Bernhard Seidl; Nikita Shevchenko; Roland Stenzel; Tim C. Lueth

2011-01-01

329

Coadministration of branched-chain amino acids and lipopolysaccharide causes matrix metalloproteinase activation and blood-brain barrier breakdown.  

PubMed

Maple syrup urine disease (MSUD) is an inborn error of metabolism caused by a severe deficiency in the activity of the branched-chain ?-keto acid dehydrogenase complex, leading to accumulation of the branched-chain amino acids (BCAA) leucine, isoleucine, and valine. Infections have a significant role in precipitating acute metabolic decompensation in patients with MSUD; however, the mechanisms underlying the neurotoxicity in this disorder are poorly understood. In this study, we subjected rats to the coadministration of lipopolysaccharide (LPS), which is a major component of gram-negative bacteria cell walls, and high concentrations of BCAA (H-BCAA) to determine their effects on the permeability of the blood-brain barrier (BBB) and on the levels of matrix metalloproteinases (MMP-2 and MMP-9). Our results demonstrated that the coadministration of H-BCAA and LPS causes breakdown of the BBB and increases the levels of MMP-2 and MMP-9 in the hippocampus of these rats. On the other hand, examination of the cerebral cortex of the 10- and 30-day-old rats revealed a significant difference in Evan's Blue content after coadministration of H-BCAA and LPS, as MMP-9 levels only increased in the cerebral cortex of the 10-day-old rats. In conclusion, these results suggest that the inflammatory process associated with high levels of BCAA causes BBB breakdown. Thus, we suggest that BBB breakdown is relevant to the perpetuation of brain inflammation and may be related to the brain dysfunction observed in MSUD patients. PMID:24390570

Scaini, Giselli; Morais, Meline O S; Galant, Leticia S; Vuolo, Francieli; Dall'Igna, Dhébora M; Pasquali, Matheus A B; Ramos, Vitor M; Gelain, Daniel P; Moreira, Jose Claudio F; Schuck, Patrícia F; Ferreira, Gustavo C; Soriano, Francisco G; Dal-Pizzol, Felipe; Streck, Emilio L

2014-10-01

330

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

NASA Astrophysics Data System (ADS)

A functional vascular system forms early in development and is continually remodeled throughout the life of the organism. Impairment to the regeneration or repair of this system leads to tissue ischemia, dysfunction, and disease. The process of vascular formation and remodeling is complex, relying on local microenvironmental cues, cytokine signaling, and multiple cell types to function properly. Tissue engineering strategies have attempted to exploit these mechanisms to develop functional vascular networks for the generation of artificial tissues and therapeutic strategies to restore tissue homeostasis. The success of these strategies requires the isolation of appropriate progenitor cell sources which are straightforward to obtain, display high proliferative potential, and demonstrate an ability to form functional vessels. Several populations are of interest including endothelial colony-forming cells, a subpopulation of endothelial progenitor cells. Additionally, the development of scaffolds to deliver and support progenitor cell survival and function is crucial for the formation of functional vascular networks. The composition and biophysical properties of these scaffolds have been shown to modulate endothelial cell behavior and vessel formation. However, further investigation is needed to better understand how these mechanical properties and biophysical properties impact vessel formation. Additionally, several other cell populations are involved in neoangiogenesis and formation of tissue parenchyma and an understanding of the potential impact of these cell populations on the biophysical properties of scaffolds will also be needed to advance these strategies. This chapter examines how the biophysical properties of matrix scaffolds can influence vessel formation and remodeling and, in particular, the impact on in vivo human endothelial progenitor cell vessel formation.

Critser, Paul J.; Yoder, Mervin C.

331

Computational geometry for patient-specific reconstruction and meshing of blood vessels from MR and CT angiography.  

PubMed

Investigation of three-dimensional (3-D) geometry and fluid-dynamics in human arteries is an important issue in vascular disease characterization and assessment. Thanks to recent advances in magnetic resonance (MR) and computed tomography (CT), it is now possible to address the problem of patient-specific modeling of blood vessels, in order to take into account interindividual anatomic variability of vasculature. Generation of models suitable for computational fluid dynamics is still commonly performed by semiautomatic procedures, in general based on operator-dependent tasks, which cannot be easily extended to a significant number of clinical cases. In this paper, we overcome these limitations making use of computational geometry techniques. In particular, 3-D modeling was carried out by means of 3-D level sets approach. Model editing was also implemented ensuring harmonic mean curvature vectors distribution on the surface, and model geometric analysis was performed with a novel approach, based on solving Eikonal equation on Voronoi diagram. This approach provides calculation of central paths, maximum inscribed sphere estimation and geometric characterization of the surface. Generation of adaptive-thickness boundary layer finite elements is finally presented. The use of the techniques presented here makes it possible to introduce patient-specific modeling of blood vessels at clinical level. PMID:12846436

Antiga, Luca; Ene-Iordache, Bogdan; Remuzzi, Andrea

2003-05-01

332

[Effect of chronic administration of epaden and acetylsalicylic acid on the antithrombotic potential of blood vessel walls in rabbits].  

PubMed

The effect of a new domestic polyunsaturated fatty acid (PUFA) concentrate called epaden on the blood coagulation system was studied in comparison with acetylsalicylic acid (ASA). The antithrombotic potential of the blood vessel wall was determined by release of the inhibitors of thrombocyte aggregation, fibrinolysis activators, and anticoagulants in rabbits under immobilization induced stress conditions. In the control group, the immobilization stress resulted in a decrease of the collagen-induced platelet aggregation, a drop in the fibrinogen level, and an increase in the tissue-type plasminogen activator (t-PA) activity. The administration of ASA and epaden reduced a drop in the fibrinogen level caused by the immobilization stress. Animals receiving epaden showed a decrease in the ADP-induced platelet aggregation and an increase in the t-PA activity in comparison with the levels before modeling stressed conditions. No such effect was observed in the group treated with ASA. It is suggested that the additional antithrombotic effect of epaden observed under the immobilization stress conditions is related to a protective action of this substance on the vessel wall. PMID:12025786

Petrukhina, G N; Remov, M N; Makarov, V A; Gandel', V G

2002-01-01

333

Disturbed flow promotes deposition of leucocytes from flowing whole blood in a model of a damaged vessel wall.  

PubMed

Departure from simple laminar flow in arteries may promote the local attachment of leucocytes either to intact endothelium or platelet thrombi. We perfused blood through a chamber with a backward facing step, to observe whether adhesion from whole blood to P-selectin was indeed localized to a region of recirculating flow, and whether platelets binding to collagen in such a region could capture leucocytes. Blood flowing over the step established a stable vortex, a reattachment point where forward and backward flow separated, and a simple laminar flow with wall shear rate c. 400/s further downstream. Fluorescently labelled leucocytes were observed to attach to P-selectin immediately upstream or downstream of the reattachment point, and to roll back towards the step or away from it, respectively. There was negligible adhesion further downstream. When a P-selectin-Fc chimaera was used to coat the chamber, stable attachment occurred, again preferentially in the disturbed flow region. Numerous platelets adhered to a collagen coating throughout the chamber, although there were local maxima either side of the reattachment point. The adherent platelets captured flowing leucocytes in these regions alone. Leucocytes may adhere from flowing blood in vessels with high shear rate if the flow is disturbed. While platelets can adhere over a wider range of shear rates, their ability to capture leucocytes may be restricted to regions of disturbed flow. PMID:15257716

Skilbeck, Christopher A; Walker, Peter G; David, Tim; Nash, Gerard B

2004-08-01

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, Rüdiger

2010-03-01

335

Dual frequency method for simultaneous translation and real-time imaging of ultrasound contrast agents within large blood vessels  

PubMed Central

A dual frequency excitation method for simultaneous translation and selective real-time imaging of microbubbles is presented. The method can distinguish signals originating from free flowing and static microbubbles. This method is implemented on a programmable scanner with a broadband linear array. The programmable interface allows for dynamic variations in the acoustic parameters and aperture attributes, enabling application of this method to large blood vessels located at varying depths. The performance of the method was evaluated in vitro (vessel diameter 2 mm) by quantifying the sensitivity of the method to various acoustic, microbubble, and fluid flow parameters. It was observed that the static microbubble response maximized at the approximate resonance frequency of the microbubble population (estimated from a coulter counter measurement), thus signifying the need for dual frequency excitation. The static microbubble signal declined from 25 to 12 dB with increasing centerline flow velocities (2.65-15.9 cm/s); indicating applicable range of flow velocities. The maximum intensity of the static microbubbles signal scaled with variations in the microbubble concentration. The rate of increment of static microbubble signal was independent of microbubble concentration. It was deduced that the rate of increment of the static microbubble signal is primarily a function of the pulse frequency, whereas the maximum static microbubble signal intensity is dependent on three parameters: a) the pulse frequency, b) the flow velocity, and c) the microbubble concentration. The proposed dual frequency sequence may enable application of radiation force for optimizing the effect of targeted imaging and modulating drug delivery in large blood vessels with high flow velocities. PMID:19828229

Patil, Abhay V.; Rychak, Joshua J.; Allen, John S.; Klibanov, Alexander L.; Hossack, John A.

2009-01-01

336

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

Microsoft Academic Search

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

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

2012-01-01

337

A comparison of the structure of small blood vessels in normal, denervated and dystrophic human muscle.  

PubMed

A light- and electron-microscopic study of the small arterial vessels and capillaries in muscle from 20 patients with Duchenne muscular dystrophy failed to adduce any direct morphological evidence that the necrobiotic muscle lesions in this disease are produced by muscle ischaemia. However the electron-microscopic studies showed that the basement membrane width in 3 out of 4 cases of Duchenne dystrophy so studied was significantly less than that or normal control material. In further case of Duchenne dystrophy, selected for study because some vessels in the biopsy muscle were surrounded by small round cell infilitrates, the basement membrane width was significantly greater than that in the normal control material. In the single case of spinal muscular atrophy studied, the basement membrane width was also significantly less than the control measurements. The possible relationship of these observations to the "ischaemic" theory of the pathogenesis of muscular dystrophy is discussed. PMID:1176989

Musch, B C; Papapetropoulos, T A; McQueen, D A; Hudgson, P; Weightman, D

1975-10-01

338

The role of blood vessels in the bioconversion of leukotrienes in the pig.  

PubMed Central

Porcine pulmonary artery has the ability to convert leukotriene C4 (LTC4) to LTD4 and then to LTE4. In this vessel, there appears to be no further metabolism beyond LTE4. LTC4 (1 nM) is converted rapidly to LTD4, whereas the conversion of LTD4 to LTE4 is somewhat slower. The conversion of LTC4 to LTD4 is inhibited by the gamma-glutamyl transpeptidase inhibitor, serine-borate (45 mM). The conversion of LTD4 to LTE4 is inhibited by the aminopeptidase inhibitor, L-cysteine (10 mM). LTB4 did not appear to be metabolized by porcine pulmonary artery. These results suggest that the vessel wall may play a role in the early stages of leukotriene metabolism. PMID:3567464

Galton, S. A.; Piper, P. J.

1987-01-01

339

Synthetic reconstruction of dynamic blood flow in cortical arteries using optical coherence tomography for the evaluation of vessel compliance  

NASA Astrophysics Data System (ADS)

Optical Coherence Tomography (OCT) has recently been used to produce 3D angiography of microvasculature in the rodent brain in-vivo and blood flow maps of large vessels. Key enabling developments were novel algorithms for detecting Doppler shifts produced by moving scatterers and new scanning protocols tailored to increase sensitivity to small flow speeds. These progresses were pushed by the need for a non invasive imaging modality to monitor quantitative blood flow at a higher resolution and a greater depth than could be achieved by other means. The rationale for this work originates from new hypotheses regarding the role of blood regulation in neurodegenerative diseases and from current investigations of animal models of vascular degeneration. In this work we demonstrate the synthetic reconstruction of dynamic blood flow in mice over the course of a single cardiac cycle in an 800?m wide by ~ 3mm deep B-Frame slice with a lateral resolution of 10?m and a depth resolution of 7?m. Images were taken using a cranial window over the exposed parietal bone of mice skull. Electrocardiography (ECG) recordings were co registered with the OCT A lines at high temporal resolution. QRS peak detection was then used to locate the time value of each A-line in the cardiac cycle and to reconstruct a synthetic temporal frame over one cardiac cycle. Doppler speed in this cardiac cycle was used to measure temporal variations of flow inside arteries and of their area. Three dimensional volume scans yielded measurements of quantitative blood flow on the same arteries. Using these informations a measure of compliance could be established. Comparing measures between atherosclerotic (ATX) and wild type (WT) mice revealed higher blood flow in WT mice, suggested lower systemic compliance in the ATX group but higher compliance of cerebral vasculature on these mice. These results are consistent with expectations showing that OCT is a potential tool for in-vivo arterial compliance evaluation.

Baraghis, Edward; Bolduc, Virginie; Gillis, Marc-Antoine; Srinivasan, Vivek J.; Thorin, Éric; Boudoux, Caroline; Lesage, Frédéric

2011-03-01

340

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

Microsoft Academic Search

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

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

1996-01-01

341

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

NASA Technical Reports Server (NTRS)

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

Palazhchenko, E. F.

1979-01-01

342

Inhibition of blood vessel formation by a chondrocyte-derived extracellular matrix.  

PubMed

In this study, the chondrocyte-derived extracellular matrix (CECM) was evaluated for its activity to inhibit vessel invasion in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) and rabbit chondrocytes were plated on a bio-membrane made of CECM or human amniotic membrane (HAM). The adhesion, proliferation, and tube formation activity of HUVECs and chondrocytes were examined. The CECM and HAM powders were then mixed individually in Matrigel and injected subcutaneously into nude mice to examine vessel invasion in vivo after 1 week. Finally, a rabbit model of corneal neovascularization (NV) was induced by 3-point sutures in the upper cornea, and CECM and HAM membranes were implanted onto the corneal surface at day 5 after suture injury. The rabbits were sacrificed at 7 days after transplantation and the histopathological analysis was performed. The adhesion and proliferation of HUVECs were more efficient on the HAM than on the CECM membrane. However, chondrocytes on each membrane showed an opposite result being more efficient on the CECM membrane. The vessel invasion in vivo also occurred more deeply and intensively in Matrigel containing HAM than in the one containing CECM. In the rabbit NV model, CECM efficiently inhibited the neovessels formation and histological remodeling in the injured cornea. In summary, our findings suggest that CECM, an integral cartilage ECM composite, shows an inhibitory effect on vessel invasion both in vitro and in vivo, and could be a useful tool in a variety of biological and therapeutic applications including the prevention of neovascularization after cornea injury. PMID:24768193

Choi, Byung Hyune; Choi, Kyoung-Hwan; Lee, Hye Sook; Song, Bo Ram; Park, So Ra; Yang, Jae Wook; Min, Byoung-Hyun

2014-07-01

343

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.

Arévalo, Laura; Roche, Eva; Palero, Virginia; Martínez, Miguel Ángel; Arroyo, M. Pilar

2013-11-01

344

On the small vessel detection in high resolution retinal images.  

PubMed

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 experiments on high resolution images showed the desirable results with performance of 84.75% true positive rate and 0.15% false positive rate. PMID:17282919

Zhang, Ming; Wu, Di; Liu, Jyh-Charn

2005-01-01

345

Neuroligin 1 induces blood vessel maturation by cooperating with the ?6 integrin.  

PubMed

The synaptic protein Neuroligin 1 (NLGN1), a cell adhesion molecule, is critical for the formation and consolidation of synaptic connectivity and is involved in vascular development. The mechanism through which NLGN1 acts, especially in vascular cells, is unknown. Here, we aimed at deepening our knowledge on the cellular activities and molecular pathways exploited by endothelial NLGN1 both in vitro and in vivo. We analyzed the phenotypic consequences of NLGN1 expression modulation in endothelial cells through in vitro angiogenesis assays and the mouse postnatal retinal angiogenesis model. We demonstrate that NLGN1, whereas not affecting endothelial cell proliferation or migration, modulates cell adhesion to the vessel stabilizing protein laminin through cooperation with the ?6 integrin, a specific laminin receptor. Finally, we show that in vivo, NLGN1 and ?6 integrin preferentially colocalize in the mature retinal vessels, whereas NLGN1 deletion causes an aberrant VE-cadherin, laminin and ?6 integrin distribution in vessels, along with significant structural defects in the vascular tree. PMID:24860089

Samarelli, Anna Valeria; Riccitelli, Elena; Bizzozero, Laura; Silveira, Tatiana Nunes; Seano, Giorgio; Pergolizzi, Margherita; Vitagliano, Grazia; Cascone, Ilaria; Carpentier, Gilles; Bottos, Alessia; Primo, Luca; Bussolino, Federico; Arese, Marco

2014-07-11

346

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

347

Long-Term Blood Vessel Removal With Combined Laser and Topical Rapamycin Antiangiogenic Therapy: Implications for Effective Port Wine Stain Treatment  

PubMed Central

Background and Objectives Complete blanching of port wine stain (PWS) birthmarks after laser therapy is rarely achieved for most patients. We postulate that the low therapeutic efficacy or treatment failure is caused by regeneration and revascularization of photocoagulated blood vessels due to angiogenesis associated with the skin’s normal wound healing response. Rapamycin (RPM), an antiangiogenic agent, has been demonstrated to inhibit growth of pathological blood vessels. Our objectives were to (1) investigate whether topical RPM can inhibit reperfusion of photocoagulated blood vessels in an animal model and (2) determine the effective RPM concentration required to achieve this objective. Study Design/Materials and Methods For both laser-only and combined laser and RPM treated animals, blood vessels in the dorsal window chambers implanted on golden Syrian hamsters were photocoagulated with laser pulses. Structural and flow dynamics of blood vessels were documented with color digital photography and laser speckle imaging to evaluate photocoagulation and reperfusion. For the combined treatment group, topical RPM was applied to the epidermal side of the window daily for 14 days after laser exposure. Results In the laser-only group, 23 out of 24 photocoagulated blood vessels reperfused within 5–14 days. In the combined treatment group with different RPM formulae and concentrations, the overall reperfusion rate of 36% was much lower as compared to the laser-only group. We also found that the reperfusion rate was not linearly proportional to the RPM concentration. Conclusions With topical RPM application, the frequency of vessel reperfusion was considerably reduced, which implies that combined light and topical antiangiogenic therapy might be a promising approach to improve the treatment efficacy of PWS birthmarks. Lasers Surg. PMID:20166161

Jia, Wangcun; Sun, Victor; Tran, Nadia; Choi, Bernard; Liu, Shaiw-wen; Mihm, Martin C.; Phung, Thuy L.; Nelson, J. Stuart

2010-01-01

348

Three-Dimensional Black-Blood Cardiac Magnetic Resonance Coronary Vessel Wall Imaging Detects Positive Arterial Remodeling in Patients With Nonsignificant Coronary Artery Disease  

Microsoft Academic Search

Background—Direct noninvasive visualization of the coronary vessel wall may enhance risk stratification by quantifying subclinical coronary atherosclerotic plaque burden. We sought to evaluate high-resolution black-blood 3D cardiovas- cular magnetic resonance (CMR) imaging for in vivo visualization of the proximal coronary artery vessel wall. Methods and Results—Twelve adult subjects, including 6 clinically healthy subjects and 6 patients with nonsignificant coronary artery

W. Yong Kim; Matthias Stuber; Peter Börnert; Kraig V. Kissinger; Warren J. Manning; René M. Botnar

2002-01-01

349

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

350

PROCEEDINGS ON SYNCHROTRON RADIATION: Medical application of diffraction enhanced imaging in mouse liver blood vessels  

NASA Astrophysics Data System (ADS)

Neovascularization is correlative with many processes of diseases, especially for tumor growth, invasion, and metastasis. What is more, these tumor microvessels are totally different from normal vessels in morphology. Therefore, observation of the morphologic distribution of microvessels is one of the key points for many researchers in the field. Using diffraction enhanced imaging (DEI), we observed the mirocvessles with diameter of about 40 ?m in mouse liver. Moreover, the refraction image obtained from DEI shows higher image contrast and exhibits potential use for medical applications.

Zhang, Xi; Yuan, Qing-Xi; Yang, Xin-Rong; Li, Hai-Qing; Chen, Yu; Chen, Shao-Liang; Zhu, Pei-Ping; Huang, Wan-Xia

2009-11-01

351

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 102.3±11.5%, the fine particle fractions (FPF) were 60.5±5.6% and the mass median aerodynamic diameters (MMAD) were 2.3±0.3?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

352

The Location of The Inferior and Superior Temporal Blood Vessels and Inter-Individual Variability of The Retinal Nerve Fiber Layer Thickness  

PubMed Central

Purpose To determine if adjusting for blood vessel location can decrease the inter-subject variability of retinal nerve fiber (RNFL) thickness measured with optical coherence tomography (OCT). Subjects and Methods One eye of 50 individuals with normal vision was tested with OCT and scanning laser polarimetry (SLP). The SLP and OCT RNFL thickness profiles were determined for a peripapillary circle 3.4 mm in diameter. The midpoints between the superior temporal vein and artery (STva) and the inferior temporal vein and artery (ITva) were determined at the location where the vessels cross the 3.4 mm circle. The average OCT and SLP RNFL thicknesses for quadrants and arcuate sectors of the lower and upper optic disc were obtained before and after adjusting for blood vessel location. This adjustment was done by shifting the RNFL profiles based upon the locations of the STva and ITva relative to the mean locations of all 50 individuals. Results Blood vessel locations ranged over 39° (STva) and 33° (ITva) for the 50 eyes. The location of the leading edge of the OCT and SLP profiles was correlated with the location of the blood vessels for both the superior [r=0.72 (OCT) and 0.72(SLP)] and inferior [r=0.34 and 0.43] temporal vessels. However, the variability in the OCT and SLP thickness measurements showed little change due to shifting. After shifting, the difference in the coefficient of variation ranged from ?2.1% (shifted less variable) to +1.7% (unshifted less variable). Conclusion The shape of the OCT and SLP RNFL profiles varied systematically with the location of the superior and inferior superior veins and arteries. However, adjusting for the location of these major temporal blood vessels did not decrease the variability for measures of OCT or SLP RNFL thickness. PMID:19661824

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

2009-01-01

353

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 fluid–structure interaction methods are being employed to model blood flow and vessel wall dynamics, tissue properties are often assumed to be uniform. In this paper, we propose a novel workflow for simulating blood flow using subject-specific geometry and spatially varying wall properties. The geometric model construction is based on 3D segmentation and geometric processing. Variable wall properties are assigned to the model based on combining centerline-based and surface-based methods. We finally demonstrate these new methods using an idealized cylindrical model and two subject-specific vascular models with thoracic and cerebral aneurysms. PMID:21765984

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

2011-01-01

354

Detergent-enzymatic decellularization of swine blood vessels: insight on mechanical properties for vascular tissue engineering.  

PubMed

Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term. Decellularization is the complete removal of all cellular and nuclear matters from a tissue while leaving a preserved extracellular matrix representing a promising tool for the generation of acellular scaffolds for tissue engineering, already used for various tissues with positive outcomes. The aim of this work is to investigate the effect of a detergent-enzymatic decellularization protocol on swine arteries in terms of cell removal, extracellular matrix preservation, and mechanical properties. Furthermore, the effect of storage at -80°C on the mechanical properties of the tissue is evaluated. Swine arteries were harvested, frozen, and decellularized; histological analysis revealed complete cell removal and preserved extracellular matrix. Furthermore, the residual DNA content in decellularized tissues was far low compared to native one. Mechanical testings were performed on native, defrozen, and decellularized tissues; no statistically significant differences were reported for Young's modulus, ultimate stress, compliance, burst pressure, and suture retention strength, while ultimate strain and stress relaxation of decellularized vessels were significantly different from the native ones. Considering the overall results, the process was confirmed to be suitable for the generation of acellular scaffolds for vascular tissue engineering. PMID:23865072

Pellegata, Alessandro F; Asnaghi, M Adelaide; Stefani, Ilaria; Maestroni, Anna; Maestroni, Silvia; Dominioni, Tommaso; Zonta, Sandro; Zerbini, Gianpaolo; Mantero, Sara

2013-01-01

355

Detergent-Enzymatic Decellularization of Swine Blood Vessels: Insight on Mechanical Properties for Vascular Tissue Engineering  

PubMed Central

Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term. Decellularization is the complete removal of all cellular and nuclear matters from a tissue while leaving a preserved extracellular matrix representing a promising tool for the generation of acellular scaffolds for tissue engineering, already used for various tissues with positive outcomes. The aim of this work is to investigate the effect of a detergent-enzymatic decellularization protocol on swine arteries in terms of cell removal, extracellular matrix preservation, and mechanical properties. Furthermore, the effect of storage at ?80°C on the mechanical properties of the tissue is evaluated. Swine arteries were harvested, frozen, and decellularized; histological analysis revealed complete cell removal and preserved extracellular matrix. Furthermore, the residual DNA content in decellularized tissues was far low compared to native one. Mechanical testings were performed on native, defrozen, and decellularized tissues; no statistically significant differences were reported for Young's modulus, ultimate stress, compliance, burst pressure, and suture retention strength, while ultimate strain and stress relaxation of decellularized vessels were significantly different from the native ones. Considering the overall results, the process was confirmed to be suitable for the generation of acellular scaffolds for vascular tissue engineering. PMID:23865072

Pellegata, Alessandro F.; Asnaghi, M. Adelaide; Stefani, Ilaria; Maestroni, Anna; Maestroni, Silvia; Dominioni, Tommaso; Zonta, Sandro; Zerbini, Gianpaolo; Mantero, Sara

2013-01-01

356

5-HT1B-receptors and vascular reactivity in human isolated blood vessels: assessment of the potential craniovascular selectivity of sumatriptan  

PubMed Central

Aims 5-HT1B-receptor mediated vasoconstriction of cranial arteries is a potential mechanism by which 5-HT1B/1D-receptor agonists such as sumatriptan produce their antimigraine effects. 5-HT1B-receptors exist in other blood vessels which may give rise to unwanted vascular effects. Therefore we examined the distribution of 5-HT1B-receptor immunoreactivity (i.r.) in human blood vessels (including target and nontarget vessels) and confirmed the functionality of this receptor protein, by comparing the vasoconstrictor effects of sumatriptan and 5-HT (the endogenous ligand) in isolated vessels. Methods Blood vessels (middle meningeal, pial, temporal and uterine arteries and saphenous veins) were obtained from surgical patients (with consent). Sections of the vessels were prepared for routine immunohistochemical studies using specific 5-HT1B- and 5-HT1D-receptor antibodies. For functional studies, ring segments of the vessels were mounted in organ baths for isometric tension recording. Results 5-HT1B-receptor i.r. was detected on the smooth muscle layer in middle meningeal, pial and uterine arteries and in saphenous vein and sumatriptan produced contractions in these vessels with potency values (mean pEC50) of 7.00, 7.08, 6.44 and 6.61, respectively, the magnitude of contraction was greatest in the cranial arteries with Emax values of 100.7, 60.3, 23.0 and 35.9%, respectively (expressed as a percentage of the reference agonist 45 mm KCl). 5-HT1B-receptor i.r. was not detected in temporal artery and sumatriptan had no effect in this artery. 5-HT1D-receptor i.r. was not detected in any of the vessels studied. Conclusions Sumatriptan can evoke vasoconstriction in antimigraine target vessels and also in nontarget vessels through an action at 5-HT1B-rcceptors. Sumatriptan acts preferentially to cause contraction in human cranial arteries compared with the other blood vessels we examined and this effect is likely to be shared by other drugs of this class. PMID:11874390

Razzaque, Z; Pickard, J D; Ma, Q-P; Shaw, D; Morrison, K; Wang, T; Longmore, J

2002-01-01

357

[Intravascular laser irradiation of blood in complex treatment of obliterating atherosclerosis of the lower extremity vessels in elderly and senile patients].  

PubMed

The authors describe comparative results of treatment of 60 elderly and senile patients with obliterating atherosclerosis of the lower extremity vessels. In 50 patients treatment with traditional medicines was combined with intravascular laser irradiation of blood, 10 patients were treated with traditional medicines only. The data obtained by questionnaires concerning the patients' state, expert judgment of doctors in charge of the profile department, indices of instrumental examinations of regional hemodynamics (rheovasography of the lower extremity vessels), data of laboratory investigations of morphofunctional state of erythrocytes and hemorheology showed that laser irradiation of blood gave better results of treatment. Its therapeutic effect persisted during 3 months in most patients. PMID:17120419

Iaitski?, N A; Ageenko, E M; Davydenko, T E; Volchkov, V A; Churzin, O A; Zharskaia, V D

2006-01-01

358

A small synthetic molecule forms selective potassium channels to regulate cell membrane potential and blood vessel tone.  

PubMed

In living cell membranes, K(+) permeability is higher than that of other ions such as Na(+) and Cl(-) owing to abundantly expressed K(+) channels. Polarized membrane potential is mainly established by K(+) outward flow because the K(+) concentration in the intracellular side is much higher than that in the extracellular side. We have found that the small synthetic molecule 1 is capable of self-assembling into selective K(+) channels, enhancing K(+) permeability and hyperpolarizing liposome membrane potential. Interestingly, molecule 1 also functions as K(+) channel hyperpolarizing living cell membrane potential and relaxing agonist-induced blood vessel contraction. Therefore, it may have the potential to become a lead compound for the treatment of human diseases associated with K(+) channel dysfunction. PMID:25183342

Zha, Hui-Yan; Shen, Bing; Yau, Kwok-Hei; Li, Shing-To; Yao, Xiao-Qiang; Yang, Dan

2014-11-01

359

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

360

Tumor blood vessel "normalization" improves the therapeutic efficacy of boron neutron capture therapy (BNCT) in experimental oral cancer.  

PubMed

We previously demonstrated the efficacy of BNCT mediated by boronophenylalanine (BPA) to treat tumors in a hamster cheek pouch model of oral cancer with no normal tissue radiotoxicity and moderate, albeit reversible, mucositis in precancerous tissue around treated tumors. It is known that boron targeting of the largest possible proportion of tumor cells contributes to the success of BNCT and that tumor blood vessel normalization improves drug delivery to the tumor. Within this context, the aim of the present study was to evaluate the effect of blood vessel normalization on the therapeutic efficacy and potential radiotoxicity of BNCT in the hamster cheek pouch model of oral cancer. Blood vessel normalization was induced by two doses of thalidomide in tumor-bearing hamsters on 2 consecutive days. All studies in thalidomide-treated animals were performed 48 h after the first dose of thalidomide, previously established as the window of normalization. Biodistribution studies were performed with BPA at a dose of 15.5 mg (10)B/kg in thalidomide-treated (Th+) and untreated (Th-) tumor-bearing hamsters. The effect of blood vessel normalization prior to BPA administration on the efficacy of BNCT was assessed in in vivo BNCT studies at the RA-3 Nuclear Reactor in tumor-bearing hamsters. Group I was treated with BPA-BNCT after treatment with thalidomide (Th+ BPA-BNCT). Group II was treated with BPA-BNCT alone (Th- BPA-BNCT). Group III was treated with the beam only after treatment with thalidomide (Th+ BO), and Group IV was treated with the beam only (Th- BO). Groups I and II were given the same dose of BPA (15.5 mg (10)B/kg), and all groups (I-IV) were exposed to the same neutron fluence. Two additional groups were treated with the beam only at a higher dose to exacerbate mucositis in precancerous tissue and to explore the potential direct protective effect of thalidomide on radiation-induced mucositis in a scenario of more severe toxicity, i.e. Group V (Th+ hdBO) and Group VI (Th- hdBO). The animals were followed for 28 days. Biodistribution studies revealed no statistically significant differences in gross boron content between Th+ and Th- animals. Overall tumor control (complete response + partial response) at 28 days post-treatment was significantly higher for Group I (Th+ BPA-BNCT) than for Group II (Th- BPA-BNCT): 84 ± 3% compared to 67 ± 5%. Pretreatment with thalidomide did not induce statistically significant changes in overall tumor control induced by the beam only, i.e. 15 ± 5% in Group III (Th+ BO) and 18 ± 5% in Group IV (Th- BO), or in overall tumor control induced by the high-dose beam only, i.e. 60 ± 7% in Group V (Th+ hdBO) and 47 ± 10% in Group VI (Th- hdBO). BPA-BNCT alone (Group II) induced mucositis in precancerous tissue that reached Grades 3-4 in 80% of the animals, whereas pretreatment with thalidomide (Group I) prevented mucositis Grades 3 and 4 completely. Beam-only Group III (Th+ BO) exhibited only Grade 1 mucositis in precancerous tissue, whereas 17% of the animals in beam-only Group IV (Th- BO) reached Grade 2 mucositis. High-dose beam-only group V (Th+ hdBO) exhibited only Grade 2 mucositis, whereas high-dose beam-only group VI (Th- hdBO) reached Grade 3 mucositis in 83% of the animals. In all cases mucositis in precancerous tissue was reversible. No normal tissue radiotoxicity was observed with any of the protocols. Pretreatment with thalidomide enhanced the therapeutic efficacy of BNCT and reduced precancerous tissue toxicity. PMID:21980958

Molinari, Ana J; Pozzi, Emiliano C C; Monti Hughes, Andrea; Heber, Elisa M; Garabalino, Marcela A; Thorp, Silvia I; Miller, Marcelo; Itoiz, Maria E; Aromando, Romina F; Nigg, David W; Trivillin, Verónica A; Schwint, Amanda E

2012-01-01

361

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

362

CLASSICAL AREAS OF PHENOMENOLOGY: Lattice Boltzmann simulation of behaviour of particles moving in blood vessels under the rolling massage  

NASA Astrophysics Data System (ADS)

The rolling massage is one of the most important manipulations in Chinese massage, which is expected to eliminate many diseases. Here, the effect of the rolling massage on a pair of particles moving in blood vessels under rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulated results show that the motion of each particle is considerably modified by the rolling massage, and it depends on the relative rolling velocity, the rolling depth, and the distance between particle position and rolling position. Both particles' translational average velocities increase almost linearly as the rolling velocity increases, and obey the same law. The increment of the average relative angular velocity for the leading particle is smaller than that of the trailing one. The result is helpful for understanding the mechanism of the massage and to further develop the rolling techniques.

Yi, Hou-Hui; Yang, Xiao-Feng; Wang, Cai-Feng; Li, Hua-Bing

2009-07-01

363

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 1–2 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 3.5±1.0%. 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

364

Apolipoprotein E4 and beta amyloid in senile plaques and cerebral blood vessels of aged rhesus monkeys.  

PubMed Central

Recent studies of late onset familial and sporadic Alzheimer's disease (AD) show a genetic disequilibrium between inheritance of the epsilon 4 allele of the apolipoprotein E (ApoE) gene and development of AD. beta-Amyloid (A beta)-positive senile plaques and blood vessels in AD are immunoreactive for ApoE, suggesting that ApoE plays a role in amyloid deposition. We examined the brains of nine rhesus monkeys (Macaca mulatta) to determine the immunohistochemical distribution of ApoE and to investigate the association of ApoE with A beta in this species. Antibodies to ApoE and A beta labeled senile plaques and vessels in the brains of aged monkeys, indicating cross-species homogeneity of the association of these two proteins. Polymerase chain reaction/restriction enzyme analysis of the ApoE epsilon 3/epsilon 4 allelic site (residue 112) in the rhesus monkey revealed that the rhesus has an arginine at this site like the human epsilon 4 allele, the cynomolgus monkey, baboon, cow, pig, mouse, and rat but unlike the human epsilon 3 allele and the rabbit. These results emphasize the value of aged nonhuman primates as animal models for A beta deposition and ApoE4-A beta interactions in AD and aging. Images Figure 1 Figure 2 PMID:8203459

Poduri, A.; Gearing, M.; Rebeck, G. W.; Mirra, S. S.; Tigges, J.; Hyman, B. T.

1994-01-01

365

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; L'Heureux, Nicolas

2009-01-01

366

Quantitative Ex-Vivo Micro-Computed Tomographic Imaging of Blood Vessels and Necrotic Regions within Tumors  

PubMed Central

Techniques for visualizing and quantifying the microvasculature of tumors are essential not only for studying angiogenic processes but also for monitoring the effects of anti-angiogenic treatments. Given the relatively limited information that can be gleaned from conventional 2-D histological analyses, there has been considerable interest in methods that enable the 3-D assessment of the vasculature. To this end, we employed a polymerizing intravascular contrast medium (Microfil) and micro-computed tomography (micro-CT) in combination with a maximal spheres direct 3-D analysis method to visualize and quantify ex-vivo vessel structural features, and to define regions of hypoperfusion within tumors that would be indicative of necrosis. Employing these techniques we quantified the effects of a vascular disrupting agent on the tumor vasculature. The methods described herein for quantifying whole tumor vascularity represent a significant advance in the 3-D study of tumor angiogenesis and evaluation of novel therapeutics, and will also find potential application in other fields where quantification of blood vessel structure and necrosis are important outcome parameters. PMID:22848565

Downey, Charlene M.; Singla, Arvind K.; Villemaire, Michelle L.; Buie, Helen R.; Boyd, Steven K.; Jirik, Frank R.

2012-01-01

367

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

368

Changes in aldehyde dehydrogenase 2 expression in rat blood vessels during glyceryl trinitrate tolerance development and reversal  

PubMed Central

BACKGROUND AND PURPOSE Recent studies have suggested an essential role for aldehyde dehydrogenase 2 (ALDH2) in the bioactivation of organic nitrates such as glyceryl trinitrate (GTN). In the present study, we utilized an in vivo GTN tolerance model to further investigate the role of ALDH2 in GTN bioactivation and tolerance. EXPERIMENTAL APPROACH We assessed changes in aortic ALDH activity, and in ALDH2 protein expression in various rat blood vessels (aorta, vena cava, femoral artery and femoral vein) during continuous GTN exposure (0.4 mg·h?1 for 6, 12, 24 or 48 h) or after a 1-, 3- or 5-day drug-free period following a 48 h exposure to GTN, in relation to changes in vasodilator responses to GTN and in vascular GTN biotransformation. KEY RESULTS A decrease was observed in both ALDH2 protein expression (80% in tolerant veins and 30% in tolerant arteries after 48 h exposure to GTN) and aortic ALDH activity, concomitant with decreased vasodilator responses to GTN and decreased aortic GTN biotransformation. However, after a 24 h drug-free period following 48 h of GTN exposure, vasodilator responses to GTN and aortic GTN biotransformation activity had returned to control values, whereas vascular ALDH2 expression and aortic ALDH activity were still significantly depressed, and remained so for 3–5 days following cessation of GTN exposure. CONCLUSIONS AND IMPLICATIONS The dissociation of reduced ALDH activity and ALDH2 expression from the duration of the impaired vasodilator and biotransformation responses to GTN in nitrate-tolerant blood vessels, suggests that factors other than changes in ALDH2-mediated GTN bioactivation contribute to nitrate tolerance. PMID:21506955

D'Souza, Y; Dowlatshahi, S; Bennett, BM

2011-01-01

369

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

2012-01-01

370

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 body’s 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

371

Intravascular Ultrasound Detection of Vasa Vasorum Blood Flow Distribution in Coronary Artery Vessel Wall  

PubMed Central

There is an increased body of evidence to suggest that the vasa vasorum play a major role in the progression and complications of vulnerable plaque leading to acute coronary syndrome. We propose the concept that detecting changes in the flow in the vascular wall by IVUS signals can quantify the presence of vasa vasorum. The results obtained in porcine model of atherosclerosis suggest that IVUS-based estimates of blood flow in the arterial wall can be used in vivo in a clinical research setting to establish the density of vasa vasorum as an indicator of plaque vulnerability. PMID:22974807

Moritz, Regina; Eaker, Diane R.; Anderson, Jill L.; Kline, Timothy L.; Jorgensen, Steven M.; Lerman, Amir; Ritman, Erik L.

2014-01-01

372

[Autologous vein bypass surgery in situ for reconstructive surgery of blood vessels of the leg].  

PubMed

The paper analyzes the authors' own experience with femorodistal bypass surgery in situ in patients with lower extremity vascular occlusive lesions. The patent distal bed and the intact superficial saphena are obligatory conditions for these operations. The paper details the surgical procedure, criteria for adequate blood flow recovery, the spectrum and incidence of complications in the immediate postoperative period. The beginning of the paper presents a brief review of the data available in the literature, which shows the present status of this worldwide problem. PMID:9461821

Gavrilenko, A V; Skrylev, S I; Kosenkov, A N; Dzhabbarov, V V

1997-01-01

373

Structure of steroids and their diffusion through blood vessel walls in a counter-current system  

SciTech Connect

Several substances including prostaglandin F2 alpha, progesterone and /sup 85/krypton have been shown to be transferred from the venous side to the arterial side of the circulation in the ovarian vascular pedicle. Experiments were therefore carried out to study the transfer of three pairs of steroids (progesterone and 20 alpha-dihydroprogesterone, C-21; androstenedione and testosterone, C-19; and estrone and estradiol-17 beta, C-18) in which each member of a pair differed by one hydroxyl group. Each pair of steroids, one labeled with /sup 3/H and the other with /sup 14/C, were infused in sequence for 30 minutes into a side branch of an ovarian vein near the hilus of the ovary with a rest period of 90 minutes between infusions. An increase in radioactivity in ovarian arterial plasma compared to the radioactivity in an equal volume of aortic plasma sampled simultaneously was used as the index for a direct transfer of steroids from the ovarian vein to the adjacent ovarian artery. All six steroids showed such a transfer which began 3 to 6 minutes after the start of each infusion and decreased rapidly after the infusion was stopped. The results of this study also showed that a larger quantity of the less polar (ketonic) form of each steroid pair examined was transferred than its hydroxyl counterpart.

McCracken, J.A.; Schramm, W.; Einer-Jensen, N.

1984-03-01

374

The Construction of Tissue-Engineered Blood Vessels Crosslinked with Adenosine-Loaded Chitosan/?-Cyclodextrin Nanoparticles using a Layer-by-Layer Assembly Method.  

PubMed

A tissue-engineered blood vessel (TEBV) modified with CS/?-CD nanoparticles is constructed, effectively controling the release of adenosine, and this type of TEBV can keep open for over 6 months. This study also demonstrates for the first time that adenosine promotes endothelial progenitor cell (EPC) mobilization and homing via energy conversion, achieving rapid endothelialization of TEBV. PMID:24947939

Chen, Wen; Zeng, Wen; Wu, Yangxiao; Wen, Can; Li, Li; Liu, Ge; Shen, Lei; Yang, Mingcan; Tan, Ju; Zhu, Chuhong

2014-11-01

375

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

Microsoft Academic Search

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

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

2007-01-01

376

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

377

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; Szabó, L; Bóta, A; Varga, Z; Machovich, R; Longstaff, C; Kolev, K

2013-01-01

378

Histological assessment of selected blood vessels of the phocid seals (northern elephant and harbour seals).  

PubMed

Phocid seals exhibit vascular adaptations that allow them to undertake prolonged deep dives. These vascular adaptations are either unique to phocids, or are modified vascular equivalents to those present in terrestrial mammals. One such adaptation, the aortic bulb, is a spherical enlargement of the ascending aorta specific to phocid seals. Its histological make-up consists of a reinforced tunica media with circular and longitudinal layers of elastic fibres. This reinforcement enables multi-axial deformation of the aortic bulb, thus complementing its function as a prominent elastic reservoir or 'windkessel'. A second adaptation, the hepatic sinus, is an asymmetrical dilation of the abdominal portion of the caudal vena cava and accompanying hepatic veins. The hepatic sinus is comprised of a relatively thin tunica media, with a scant smooth muscle component. The bulk of the sinus wall is comprised of tunica adventitia. A third vascular adaptation distinctive to the phocids is the pericardial venous plexus, composed of convoluted veins circumnavigating the perimeter of the heart. Microscopically, these veins have a thick tunica media and also contain valves. Smaller arteries, venules and distinct capillary beds are observed interspersed in-between these veins. It can be hypothesized, that in seals, certain vascular embryonic development may be arrested at an earlier embryonic stage, resulting in these unusual vascular formations. These modifications play a vital role in blood pressure regulation and distribution of oxygenated blood during prolonged deep diving. The purpose of this work was to elucidate the histological aspects of these unique vascular modifications and relate them to specific function. PMID:20331589

Smodlaka, H; Khamas, W; Tkalcic, S; Golub, T; Palmer, L

2010-06-01

379

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 ...

380

Gene expression analysis of the microvascular compartment in multiple sclerosis using laser microdissected blood vessels.  

PubMed

The blood brain barrier (BBB) is formed by capillary endothelial cells with inter-endothelial cell tight junctions and other cells such as pericytes and astrocytes present. Previous studies have shown a role for tight junction abnormalities in BBB leakage in multiple sclerosis (MS) brain. This marks a key stage in the development of inflammatory demyelination in MS. The aim of this study was to identify aberrantly expressed genes involved in BBB changes in MS lesions. A focused endothelial cell biology microarray, capable of detecting changes in expression of 113 endothelial cell-specific genes, was employed to analyse endothelial cell mRNA extracted from post-mortem control white matter, MS normal appearing white matter (NAWM), chronic active or inactive lesions by laser capture microdissection. Microarray analysis found 52 genes out of 113 analysed, predominantly in the activation functional group, to be differentially expressed in lesions compared to control or NAWM (p < 0.01). The majority of the differentially expressed genes were validated by quantitative real time PCR. In addition, the protein expression profiles of ICAM2, MMP2, and VEGFR1 were examined by immunofluorescent staining of selected tissue blocks. ICAM-2 was expressed at a higher level in chronic inactive lesions than control or NAWM, corresponding with the increased mRNA measured by microarray and real time PCR. The data shown, presenting a number of differentially expressed genes in the microvascular compartment of MS lesions, may shed light on the molecular mechanisms that are involved in the breakdown of the BBB. This moves us a step closer to the identification of potential therapeutic targets for repair of the compromised BBB. PMID:19967542

Cunnea, Paula; McMahon, Jill; O'Connell, Enda; Mashayekhi, Kaveh; Fitzgerald, Una; McQuaid, Stephen

2010-05-01

381

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 ...

382

Age-related brain pathology in Octodon degu: blood vessel, white matter and Alzheimer-like pathology.  

PubMed

Recently it has been shown that over 3-year-old wild-type South American rodents, Octodon degus, the "common degu" or degu, of their own accord develop Alzheimer's disease neuropathological hallmarks: amyloid-?-peptide depositions and accumulation of tau-protein. Here we analyzed brains of 1-, 3- and 6-year-old degu's, bred in standard animal facilities. Significant amounts of A? and tau deposits are present in the hippocampal formation of 6-year-old O. degus, primarily in the white matter, but these hippocampal A? and tau deposits are not present in younger ones. In contrast, significant A? deposits in blood vessel walls are already found in 3-year-old animals. The tau deposits in the hippocampal formation coincide with a significant decrease in staining for myelin in the same areas, indicating hippocampal disconnection and, likely, dysfunction. Our findings indicate that (1) cerebral amyloid angiopathy precedes brain parenchyma pathology in aged degu's and (2) the onset of disease seems to be delayed in the laboratory vs. wild-type degu's. PMID:19910078

van Groen, Thomas; Kadish, Inga; Popovi?, Natalija; Popovi?, Miroljub; Caballero-Bleda, María; Baño-Otálora, Beatriz; Vivanco, Pablo; Rol, María Ángeles; Madrid, Juan Antonio

2011-09-01

383

Endosome-to-Plasma Membrane Recycling of VEGFR2 Receptor Tyrosine Kinase Regulates Endothelial Function and Blood Vessel Formation  

PubMed Central

Rab GTPases are implicated in endosome-to-plasma membrane recycling, but how such membrane traffic regulators control vascular endothelial growth factor receptor 2 (VEGFR2/KDR) dynamics and function are not well understood. Here, we evaluated two different recycling Rab GTPases, Rab4a and Rab11a, in regulating endothelial VEGFR2 trafficking and signalling with implications for endothelial cell migration, proliferation and angiogenesis. In primary endothelial cells, VEGFR2 displays co-localisation with Rab4a, but not Rab11a GTPase, on early endosomes. Expression of a guanosine diphosphate (GDP)-bound Rab4a S22N mutant caused increased VEGFR2 accumulation in endosomes. TfR and VEGFR2 exhibited differences in endosome-to-plasma membrane recycling in the presence of chloroquine. Depletion of Rab4a, but not Rab11a, levels stimulated VEGF-A-dependent intracellular signalling. However, depletion of either Rab4a or Rab11a levels inhibited VEGF-A-stimulated endothelial cell migration. Interestingly, depletion of Rab4a levels stimulated VEGF-A-regulated endothelial cell proliferation. Rab4a and Rab11a were also both required for endothelial tubulogenesis. Evaluation of a transgenic zebrafish model showed that both Rab4 and Rab11a are functionally required for blood vessel formation and animal viability. Rab-dependent endosome-to-plasma membrane recycling of VEGFR2 is important for intracellular signalling, cell migration and proliferation during angiogenesis. PMID:24785348

Jopling, Helen M.; Odell, Adam F.; Pellet-Many, Caroline; Latham, Antony M.; Frankel, Paul; Sivaprasadarao, Asipu; Walker, John H.; Zachary, Ian C.; Ponnambalam, Sreenivasan

2014-01-01

384

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 ...

385

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 ...

386

Automatic retinal blood flow calculation using spectral domain optical coherence tomography  

NASA Astrophysics Data System (ADS)

Optical Doppler tomography (ODT) is a branch of optical coherence tomography (OCT) that can measure the speed of a blood flow by measuring the Doppler shift impinged on the probing sample light by the moving blood cells. However, the measured speed of blood flow is a function of the Doppler angle, which needs to be determined in order to calculate the absolute velocity of the blood flow inside a vessel. We developed a technique that can extract the Doppler angle from the 3D data measured with spectral-domain OCT, which needs to extract the lateral and depth coordinates of a vessel in each measured ODT and OCT image. The lateral coordinates and the diameter of a blood vessel were first extracted in each OCT structural image by using the technique of blood vessel shadowgram, a technique first developed by us for enhancing the retinal blood vessel contrast in the en face view of the 3D OCT. The depth coordinate of a vessel was then determined by using a circular averaging filter moving in the depth direction along the axis passing through the vessel center in the ODT image. The Doppler angle was then calculated from the extracted coordinates of the blood vessel. The technique was applied in blood flow measurements in retinal blood vessels, which has potential impact on the study and diagnosis of blinding diseases like glaucoma and diabetic retinopathy.

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

2008-02-01

387

[Ultrastructure of the blood vessels and muscle fibers in the skeletal muscle of rats flown on the Kosmos-605 and Kosmos-782 biosatellites].  

PubMed

Electron microscopy was used to study ultrastructures of the wall of blood vessels and muscle fibers of the red (soleus) and mixed (gastrocnemius) muscles of rats flown on Cosmos-605 for 22.5 days and on Cosmos-782 for 19,5 days and sacrificed 4-6 hours, 48 hours and 25-27 days postflight. It was demonstrated that the orbital flight did not induce significant changes in the ultrastructure of blood vessels of the soleus and gastrocnemius muscles but caused atrophy of muscle fibers and reduction of the number of functioning capillaries. Readaptation of the soleus vascular system to 1 g led to degradation of permeability of capillary and venular walls and development of edema of the perivascular connective tissue. This may be one of the factors responsible for dystrophic changes in muscle fibers. PMID:7289571

Savik, Z F; Rokhlenko, K D

1981-01-01

388

Branched-chain amino acids increase arterial blood ammonia in spite of enhanced intrinsic muscle ammonia metabolism in patients with cirrhosis and healthy subjects.  

PubMed

Branched-chain amino acids (BCAA) are used in attempts to reduce blood ammonia in patients with cirrhosis and intermittent hepatic encephalopathy based on the hypothesis that BCAA stimulate muscle ammonia detoxification. We studied the effects of an oral dose of BCAA on the skeletal muscle metabolism of ammonia and amino acids in 14 patients with cirrhosis and in 7 healthy subjects by combining [(13)N]ammonia positron emission tomography (PET) of the thigh muscle with measurements of blood flow and arteriovenous (A-V) concentrations of ammonia and amino acids. PET was used to measure the metabolism of blood-supplied ammonia and the A-V measurements were used to measure the total ammonia metabolism across the thigh muscle. After intake of BCAA, blood ammonia increased more than 30% in both groups of subjects (both P < 0.05). Muscle clearance of blood-supplied ammonia (PET) was unaffected (P = 0.75), but the metabolic removal rate (PET) increased significantly because of increased blood ammonia in both groups (all P < 0.05). The total ammonia clearance across the leg muscle (A-V) increased by more than 50% in both groups, and the flux (A-V) of ammonia increased by more than 45% (all P < 0.05). BCAA intake led to a massive glutamine release from the muscle (cirrhotic patients, P < 0.05; healthy subjects, P = 0.12). In conclusion, BCAA enhanced the intrinsic muscle metabolism of ammonia but not the metabolism of blood-supplied ammonia in both the patients with cirrhosis and in the healthy subjects. PMID:21636533

Dam, Gitte; Keiding, Susanne; Munk, Ole Lajord; Ott, Peter; Buhl, Mads; Vilstrup, Hendrik; Bak, Lasse Kristoffer; Waagepetersen, Helle Sønderby; Schousboe, Arne; Møller, Niels; Sørensen, Michael

2011-08-01

389

Changes in the distribution of anionic sites in brain micro-blood vessels with and without amyloid deposits in scrapie-infected mice  

Microsoft Academic Search

Cationic colloidal gold (CCG) and scrapie-infected mouse brain samples embedded in Lowicryl K4M were used for ultrastructural localization of negatively charged microdomains (anionic sites) in the cerebral microvasculature. The distribution of anionic sites on both fronts (luminal and abluminal) of endothelial cells and in the basement membrane (BM) in the majority of micro-blood vessels (MBVs) located outside the plaque area

A. W. Vorbrodt; D. H. Dobrogowska; A. S. Lossinsky; H. M. Wisniewski

1990-01-01

390

Initial Results of an Automatic Blood-Vessel Segmentation Procedure in Digital Fundus Photographs via Multiscale Line Operators and Global Threshold Selection  

Microsoft Academic Search

A multiscale line operator (MSLO) approach was employed in order to segment blood vessels in digital fundus images. This approach was used for images in the STARE retinal image archive (www.ces.clemson.edu\\/~ahoover\\/stare\\/). The STARE dataset contained both healthy (10 images) and diseased eyes (10 images) at a variety of field widths. Otsu threshold selection was employed in order to provide a

D. J. J. Farnell

391

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

392

AN AUTOMATIC BRANCH AND STENOSES DETECTION IN COMPUTED TOMOGRAPHY ANGIOGRAPHY  

E-print Network

, segmentation, CTA, tubular structures, branch detection, vessel trees, coronary ar- teries 1. INTRODUCTION aim to extract coronary vessel branches from CTA scans and to detect possible abnormalities on arter to remove calcifications on arteries. Then, we detect the branches in a vessel tree (Sec- tion 2.3) based

Yanikoglu, Berrin

393

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

394

The relationship between branched-chain amino acids and alpha-keto acids in blood in uremia.  

PubMed

Branched-chain alpha-keto acid (BCKA) supplements are used as a nitrogen-free source of branched-chain amino acids (BCAA) in patients with chronic renal failure. Their use is dependent on the freely reversible interconversion of BCKA and BCAA in muscle tissue. In a group of eight young adults on dialysis compared to 11 normal healthy adults, the ratios of the fasting plasma concentrations of leucine and isoleucine to their corresponding alpha-keto acids, alpha-keto isocaproic acid and alpha-keto-beta-methyl-eta-valeric acid, respectively, were significantly elevated. These ratios appear to be sensitive to changes in intracellular glutamate and pyruvate. The ratios increased in seven insulin-dependent diabetics following insulin withdrawal, a situation where intracellular glutamate is increased. The ratios decreased in six normal healthy adults in response to submaximal treadmill exercise, a situation where intracellular pyruvate is increased. The elevated BCAA/BCKA ratios in uremia could be a reflection of reduced peripheral glucose utilization. A consequence of this will be enhanced conversion of supplemented BCKA to their corresponding BCAA. The close association between muscle BCAA and glucose metabolism suggests that the timing of BCKA administration in relation to energy intake might prove important. PMID:6588270

Dalton, R N; Chantler, C

1983-12-01

395

K+ currents underlying the action of endothelium-derived hyperpolarizing factor in guinea-pig, rat and human blood vessels  

PubMed Central

Membrane currents attributed to endothelium-derived hyperpolarizing factor (EDHF) were recorded in short segments of submucosal arterioles of guinea-pigs using single microelectrode voltage clamp. The functional responses of arterioles and human subcutaneous, rat hepatic and guinea-pig coronary arteries were also assessed as changes in membrane potential recorded simultaneously with contractile activity. The current-voltage (I-V) relationship for the conductance due to EDHF displayed outward rectification with little voltage dependence. Components of the current were blocked by charybdotoxin (30-60 nM) and apamin (0.25-0.50 ?M), which also blocked hyperpolarization and prevented EDHF-induced relaxation. The EDHF-induced current was insensitive to Ba2+ (20-100 ?M) and/or ouabain (1 ?M to 1 mM). In human subcutaneous arteries and guinea-pig coronary arteries and submucosal arterioles, the EDHF-induced responses were insensitive to Ba2+ and/or ouabain. Increasing [K+]o to 11-21 mM evoked depolarization under conditions in which EDHF evoked hyperpolarization. Responses to ACh, sympathetic nerve stimulation and action potentials were indistinguishable between dye-labelled smooth muscle and endothelial cells in arterioles. Action potentials in identified endothelial cells were always associated with constriction of the arterioles. 18?-Glycyrrhetinic acid (30 ?M) and carbenoxolone (100 ?M) depolarized endothelial cells by 31 ± 6 mV (n = 7 animals) and 33 ± 4 mV (n = 5), respectively, inhibited action potentials in smooth muscle and endothelial cells and reduced the ACh-induced hyperpolarization of endothelial cells by 56 and 58 %, respectively. Thus, activation of outwardly rectifying K+ channels underlies the hyperpolarization and relaxation due to EDHF. These channels have properties similar to those of intermediate conductance (IKCa) and small conductance (SKCa) Ca2+-activated K+ channels. Strong electrical coupling between endothelial and smooth muscle cells implies that these two layers function as a single electrical syncytium. The non-specific effects of glycyrrhetinic acid precludes its use as an indicator of the involvement of gap junctions in EDHF-attributed responses. These conclusions are likely to apply to a variety of blood vessels including those of humans. PMID:11230509

Coleman, H A; Tare, Marianne; Parkington, Helena C

2001-01-01

396

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

397

Electro-acupuncture at Conception and Governor vessels and transplantation of umbilical cord blood-derived mesenchymal stem cells for treating cerebral ischemia/reperfusion injury.  

PubMed

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

398

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

E-print Network

to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one transport the blood, which is at a low oxygen level and thus darker, to the lungs and the liver. For many lead to narrowed arteries and high blood pressure results in thickened arteries. To detect

Cremers, Daniel

399

Measurement of blood flow velocity in a model of stenosis in vitro and in mesenteric vessels in vivo using non-invasive micro multipoint laser Doppler velocimetry  

NASA Astrophysics Data System (ADS)

Our research goal is to carry out two-dimensional (2D) and three-dimensional (3D) measurements of the velocity distribution within a single vessel. We modified a non-invasive beam laser Doppler velocimeter using near-infrared light, and linearized the laser to carry out simultaneous multipoint measurements. We also scanned the measurement line in the direction of depth to allow 3D imaging of vascular blood flow in opaque areas in vivo. We used micro multipoint laser Doppler velocimetry (LDV) and a device with improved spatial resolution from 250 to 125 µm. We compared actual and calculated values using a rotating disk with an attached microwire. To demonstrate the effectiveness of the proposed system, blood flowing at a constant rate through a glass capillary and the velocity distribution of flow in the capillary were measured and mapped. The average flow velocity was calculated from the cross-sectional area and flow rate in the glass capillary, and we compared the calculated and measured values. To obtain an image of blood flow velocity in vivo, we measured both 2D and 3D flow velocity distributions in mouse mesenteric vessels.

Akiguchi, Shunsuke; Ishida, Hiroki; Andoh, Tsugunobu; Hachiga, Tadashi; Shimizu, Tadamichi; Kuraishi, Yasushi; Shirakawa, Hiroki; Ueyama, Koji

2012-04-01

400

Development and application of a volume penalization immersed boundary method for the computation of blood flow and shear stresses in cerebral vessels and aneurysms.  

PubMed

A volume-penalizing immersed boundary method is presented for the simulation of laminar incompressible flow inside geometrically complex blood vessels in the human brain. We concentrate on cerebral aneurysms and compute flow in curved brain vessels with and without spherical aneurysm cavities attached. We approximate blood as an incompressible Newtonian fluid and simulate the flow with the use of a skew-symmetric finite-volume discretization and explicit time-stepping. A key element of the immersed boundary method is the so-called masking function. This is a binary function with which we identify at any location in the domain whether it is 'solid' or 'fluid', allowing to represent objects immersed in a Cartesian grid. We compare three definitions of the masking function for geometries that are non-aligned with the grid. In each case a 'staircase' representation is used in which a grid cell is either 'solid' or 'fluid'. Reliable findings are obtained with our immersed boundary method, even at fairly coarse meshes with about 16 grid cells across a velocity profile. The validation of the immersed boundary method is provided on the basis of classical Poiseuille flow in a cylindrical pipe. We obtain first order convergence for the velocity and the shear stress, reflecting the fact that in our approach the solid-fluid interface is localized with an accuracy on the order of a grid cell. Simulations for curved vessels and aneurysms are done for different flow regimes, characterized by different values of the Reynolds number (Re). The validation is performed for laminar flow at Re = 250, while the flow in more complex geometries is studied at Re = 100 and Re = 250, as suggested by physiological conditions pertaining to flow of blood in the circle of Willis. PMID:23192329

Mikhal, Julia; Geurts, Bernard J

2013-12-01

401

Kinking of pedicle vessels and its effect on blood flow and patency in free flaps: an experimental study in rats  

Microsoft Academic Search

Aim: Head rotation may significantly alter the initial position of the vascular pedicle of free flaps in reconstructive surgery of the oral cavity. This may lead to kinking of venous and\\/or arterial vessels. In spite of some precautions as rotating the head contralaterally for the first few days postoperatively or shortening the pedicle, the problem is still not well understood

Federico Biglioli; Marco Rabagliati; Stefano Gatti; Roberto Brusati

2004-01-01

402

Vessel tractography using an intensity based tensor model  

E-print Network

with a single seed point and it is ca- pable of capturing whole vessel tree by an automatic branch detection, tubular structures, branch detection, vessel trees, coronary arteries, tensor estimation, tractography point and entire vessel tree (Section 2.2) can be captured by an automatic branch detection algo- rithm

Yanikoglu, Berrin

403

Eight prehilar branches of the right renal artery  

PubMed Central

Imaging technology with its advancement in the field of urology is the boon for the patients who require minimally invasive approaches for various kidney disorders. These approaches require a precise knowledge of the normal and variant anatomy of vessels at the hilum of the kidney. During routine dissections, a variation in the branching pattern of the right renal artery was noted in an adult male cadaver. The right renal artery divided into upper and lower divisions 6cm away from the hilum of the kidney. The upper division gave 4 branches, and the lower division gave two branches. These two branches further bifurcated and gave 2 branches each. Thus, there were 8 prehilar branches of renal artery. The multiple prehilar branches led to a congested atmosphere at the hilum of the kidney. This arterial congestion might result in hindering the blood flow at the renal hilum. Apart from this, it might cause difficulties in diagnostic and therapeutic invasive procedures. Knowledge of this variation is of importance to radiologists and urologists in particular.

Shetty, Surekha D.; Ravindra, Swamy; Sirasanagandla, Srinivasa Rao; Aithal, Ashwini P.; Patil, Jyothsna; Kumar, Naveen

2014-01-01

404

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

E-print Network

. Numerical simulations, such as blood flow or coil deploy- ment in an intra-cranial aneurism, are very results of coil deployment simulation are also given. 1 Introduction An intracranial aneurism or death. Medical treatment consists in excluding the aneurism from blood circulation either by surgical

Paris-Sud XI, Université de

405

A hybrid electrospun PU/PCL scaffold satisfied the requirements of blood vessel prosthesis in terms of mechanical properties, pore size, and biocompatibility.  

PubMed

In this study, a novel hybrid polyurethane/polycaprolactone (PU/PCL) tubular scaffold was fabricated using the electrospinning process for blood vessel prosthesis applications. The detailed microstructure and material properties such as porosity, tensile and bust strength, contact angle, and biocompatibility were investigated and compared with those of monolithic PU and PCL scaffolds. The mechanical properties of the hybrid PU/PCL scaffold (tensile strength: 18?MPa, pressure strength: 590?mmHg) were found to be within the range needed for artificial blood vessel applications. The pore sizes of the PU/PCL scaffold ranged from 5-150?um in diameter, are sufficient enough to allow nutrient diffusion across the membrane. The reduced hydrophobic property of the PU/PCL scaffold was the result of the addition of relatively less hydrophobic PU compared with monolithic PCL scaffold. The biocompatibility of the PU/PCL scaffold was evaluated through cytotoxicity testing, and morphological observation by scanning electron microscopy and confocal microscopy using cow pulmonary artery endothelial cells and fibroblast like cells (L929). PMID:23627704

Nguyen, Thi-Hiep; Padalhin, Andrew R; Seo, Hyung Seok; Lee, Byong-Taek

2013-01-01

406

GFAP-Driven GFP Expression in Activated Mouse Müller Glial Cells Aligning Retinal Blood Vessels Following Intravitreal Injection of AAV2/6 Vectors  

PubMed Central

Background Müller cell gliosis occurs in various retinal pathologies regardless of the underlying cellular defect. Because activated Müller glial cells span the entire retina and align areas of injury, they are ideal targets for therapeutic strategies, including gene therapy. Methodology/Principal Findings We used adeno-associated viral AAV2/6 vectors to transduce mouse retinas. The transduction pattern of AAV2/6 was investigated by studying expression of the green fluorescent protein (GFP) transgene using scanning-laser ophthalmoscopy and immuno-histochemistry. AAV2/6 vectors transduced mouse Müller glial cells aligning the retinal blood vessels. However, the transduction capacity was hindered by the inner limiting membrane (ILM) and besides Müller glial cells, several other inner retinal cell types were transduced. To obtain Müller glial cell-specific transgene expression, the cytomegalovirus (CMV) promoter was replaced by the glial fibrillary acidic protein (GFAP) promoter. Specificity and activation of the GFAP promoter was tested in a mouse model for retinal gliosis. Mice deficient for Crumbs homologue 1 (CRB1) develop gliosis after light exposure. Light exposure of Crb1?/? retinas transduced with AAV2/6-GFAP-GFP induced GFP expression restricted to activated Müller glial cells aligning retinal blood vessels. Conclusions/Significance Our experiments indicate that AAV2 vectors carrying the GFAP promoter are a promising tool for specific expression of transgenes in activated glial cells. PMID:20808778

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

407

Effect of caffeine alone and in combination with strophanthin on collateral blood flow after acute occlusion of the coronary artery  

Microsoft Academic Search

By recording the retrograde blood flow and presence in the zone of distribution of the ligated anterior descending branch of the left coronary artery in acute experiments on dogs, it was shown that caffeine, in a dose of 10 mg\\/kg, increases the collateral blood flow without producing significant changes in the systemic arterial pressure or pressure in the ligated vessel.

A. V. Sapozhkov

1970-01-01

408

Exploratory Dijkstra forest based automatic vessel segmentation  

E-print Network

. Goldbaum, "Detection of blood vessels in retinal images using two-dimensional matched filters," IEEEExploratory Dijkstra forest based automatic vessel segmentation: applications in video indirect's shortest-path algorithm. Our method preserves vessel thickness, requires no manual intervention

Tomasi, Carlo

409

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