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Sample records for blood vessels based

  1. Segmentation of Retinal Blood Vessels Based on Cake Filter

    PubMed Central

    Bao, Xi-Rong; Ge, Xin; She, Li-Huang; Zhang, Shi

    2015-01-01

    Segmentation of retinal blood vessels is significant to diagnosis and evaluation of ocular diseases like glaucoma and systemic diseases such as diabetes and hypertension. The retinal blood vessel segmentation for small and low contrast vessels is still a challenging problem. To solve this problem, a new method based on cake filter is proposed. Firstly, a quadrature filter band called cake filter band is made up in Fourier field. Then the real component fusion is used to separate the blood vessel from the background. Finally, the blood vessel network is got by a self-adaption threshold. The experiments implemented on the STARE database indicate that the new method has a better performance than the traditional ones on the small vessels extraction, average accuracy rate, and true and false positive rate. PMID:26636095

  2. Three-dimensional reconstruction of pulmonary blood vessels by using anatomical knowledge base

    NASA Astrophysics Data System (ADS)

    Inaoka, Noriko; Suzuki, Hideo; Mori, Masaki; Takabatake, Hirotsugu; Suzuki, Akira

    1991-07-01

    This paper presents a knowledge-based method for automatic reconstruction and recognition of pulmonary blood vessels from chest x-ray CT images with 10-mm thickness. The system has four main stages: (1) automatic extraction and segmentation of blood vessel components from each 2-D image, (2) analysis of these components, (3) a search for points connecting blood vessel segments in different CT slices, using a knowledge base for 3-D reconstruction, and (4) object manipulation and display. The authors also describe a method of representing 3-D anatomical knowledge of the pulmonary blood vessel structure. The edges of blood vessels in chest x-ray images are unclear, in contrast to those in angiograms. Each CT slice has thickness, and blood vessels are slender, so a simple graphical display, which can be used for bone tissues from CT images, is not sufficient for pulmonary blood vessels. It is therefore necessary to use anatomical knowledge to track the blood vessel lines in 3-D spaces. Experimental results using actual images of a normal adult male has shown that utilizing anatomical information enables one to improve processing efficiency and precision, such as blood vessel extraction and searching for connecting points.

  3. Hybrid Features and Mediods Classification based Robust Segmentation of Blood Vessels.

    PubMed

    Waheed, Amna; Akram, M Usman; Khalid, Shehzad; Waheed, Zahra; Khan, Muazzam A; Shaukat, Arslan

    2015-10-01

    Retinal blood vessels are the source to provide oxygen and nutrition to retina and any change in the normal structure may lead to different retinal abnormalities. Automated detection of vascular structure is very important while designing a computer aided diagnostic system for retinal diseases. Most popular methods for vessel segmentation are based on matched filters and Gabor wavelets which give good response against blood vessels. One major drawback in these techniques is that they also give strong response for lesion (exudates, hemorrhages) boundaries which give rise to false vessels. These false vessels may lead to incorrect detection of vascular changes. In this paper, we propose a new hybrid feature set along with new classification technique for accurate detection of blood vessels. The main motivation is to lower the false positives especially from retinal images with severe disease level. A novel region based hybrid feature set is presented for proper discrimination between true and false vessels. A new modified m-mediods based classification is also presented which uses most discriminating features to categorize vessel regions into true and false vessels. The evaluation of proposed system is done thoroughly on publicly available databases along with a locally gathered database with images of advanced level of retinal diseases. The results demonstrate the validity of the proposed system as compared to existing state of the art techniques. PMID:26306876

  4. Blood Vessel Tension Tester

    NASA Technical Reports Server (NTRS)

    1978-01-01

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

  5. Tumor Blood Vessel Dynamics

    NASA Astrophysics Data System (ADS)

    Munn, Lance

    2009-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  7. A Novel Curvature-Based Algorithm for Automatic Grading of Retinal Blood Vessel Tortuosity.

    PubMed

    Aghamohamadian-Sharbaf, Masoud; Pourreza, Hamid Reza; Banaee, Touka

    2016-03-01

    Tortuosity of retinal blood vessels is an important symptom of diabetic retinopathy or retinopathy of prematurity. In this paper, we propose an automatic image-based method for measuring single vessel and vessel network tortuosity of these vessels. Simplicity of the algorithm, low-computational burden, and an excellent matching to the clinically perceived tortuosity are the important features of the proposed algorithm. To measure tortuosity, we use curvature which is an indicator of local inflection of a curve. For curvature calculation, template disk method is a common choice and has been utilized in most of the state of the art. However, we show that this method does not possess linearity against curvature and by proposing two modifications, we improve the method. We use the basic and the modified methods to measure tortuosity on a publicly available data bank and two data banks of our own. While interpreting the results, we pursue three goals. First, to show that our algorithm is more efficient to implement than the state of the art. Second, to show that our method possesses an excellent correlation with subjective results (0.94 correlation for vessel tortuosity, 0.95 correlation for vessel network tortuosity in diabetic retinopathy, and 0.7 correlation for vessel network tortuosity in retinopathy of prematurity). Third, to show that the tortuosity perceived by an expert and curvature possess a nonlinear relation. PMID:25622332

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

    NASA Astrophysics Data System (ADS)

    Nimura, Yukitaka; Kitasaka, Takayuki; Mori, Kensaku

    2010-03-01

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

  9. Optics based signal processing methods for intraoperative blood vessel detection and quantification in real time (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Amal; Shukair, Shetha A.; Le Rolland, Paul; Vijayvergia, Mayank; Subramanian, Hariharan; Gunn, Jonathan W.

    2016-03-01

    Minimally invasive operations require surgeons to make difficult cuts to blood vessels and other tissues with impaired tactile and visual feedback. This leads to inadvertent cuts to blood vessels hidden beneath tissue, causing serious health risks to patients and a non-reimbursable financial burden to hospitals. Intraoperative imaging technologies have been developed, but these expensive systems can be cumbersome and provide only a high-level view of blood vessel networks. In this research, we propose a lean reflectance-based system, comprised of a dual wavelength LED, photodiode, and novel signal processing algorithms for rapid vessel characterization. Since this system takes advantage of the inherent pulsatile light absorption characteristics of blood vessels, no contrast agent is required for its ability to detect the presence of a blood vessel buried deep inside any tissue type (up to a cm) in real time. Once a vessel is detected, the system is able to estimate the distance of the vessel from the probe and the diameter size of the vessel (with a resolution of ~2mm), as well as delineate the type of tissue surrounding the vessel. The system is low-cost, functions in real-time, and could be mounted on already existing surgical tools, such as Kittner dissectors or laparoscopic suction irrigation cannulae. Having been successfully validated ex vivo, this technology will next be tested in a live porcine study and eventually in clinical trials.

  10. Imaging blood vessels and lymphatic vessels in the zebrafish.

    PubMed

    Jung, H M; Isogai, S; Kamei, M; Castranova, D; Gore, A V; Weinstein, B M

    2016-01-01

    Blood vessels supply tissues and organs with oxygen, nutrients, cellular, and humoral factors, while lymphatic vessels regulate tissue fluid homeostasis, immune trafficking, and dietary fat absorption. Understanding the mechanisms of vascular morphogenesis has become a subject of intense clinical interest because of the close association of both types of vessels with pathogenesis of a broad spectrum of human diseases. The zebrafish provides a powerful animal model to study vascular morphogenesis because of their small, accessible, and transparent embryos. These unique features of zebrafish embryos permit sophisticated high-resolution live imaging of even deeply localized vessels during embryonic development and even in adult tissues. In this chapter, we summarize various methods for blood and lymphatic vessel imaging in zebrafish, including nonvital resin injection-based or dye injection-based vessel visualization, and alkaline phosphatase staining. We also provide protocols for vital imaging of vessels using microangiography or transgenic fluorescent reporter zebrafish lines. PMID:27263409

  11. A Morphological Hessian Based Approach for Retinal Blood Vessels Segmentation and Denoising Using Region Based Otsu Thresholding.

    PubMed

    BahadarKhan, Khan; A Khaliq, Amir; Shahid, Muhammad

    2016-01-01

    Diabetic Retinopathy (DR) harm retinal blood vessels in the eye causing visual deficiency. The appearance and structure of blood vessels in retinal images play an essential part in the diagnoses of an eye sicknesses. We proposed a less computational unsupervised automated technique with promising results for detection of retinal vasculature by using morphological hessian based approach and region based Otsu thresholding. Contrast Limited Adaptive Histogram Equalization (CLAHE) and morphological filters have been used for enhancement and to remove low frequency noise or geometrical objects, respectively. The hessian matrix and eigenvalues approach used has been in a modified form at two different scales to extract wide and thin vessel enhanced images separately. Otsu thresholding has been further applied in a novel way to classify vessel and non-vessel pixels from both enhanced images. Finally, postprocessing steps has been used to eliminate the unwanted region/segment, non-vessel pixels, disease abnormalities and noise, to obtain a final segmented image. The proposed technique has been analyzed on the openly accessible DRIVE (Digital Retinal Images for Vessel Extraction) and STARE (STructured Analysis of the REtina) databases along with the ground truth data that has been precisely marked by the experts. PMID:27441646

  12. A Morphological Hessian Based Approach for Retinal Blood Vessels Segmentation and Denoising Using Region Based Otsu Thresholding

    PubMed Central

    BahadarKhan, Khan; A Khaliq, Amir; Shahid, Muhammad

    2016-01-01

    Diabetic Retinopathy (DR) harm retinal blood vessels in the eye causing visual deficiency. The appearance and structure of blood vessels in retinal images play an essential part in the diagnoses of an eye sicknesses. We proposed a less computational unsupervised automated technique with promising results for detection of retinal vasculature by using morphological hessian based approach and region based Otsu thresholding. Contrast Limited Adaptive Histogram Equalization (CLAHE) and morphological filters have been used for enhancement and to remove low frequency noise or geometrical objects, respectively. The hessian matrix and eigenvalues approach used has been in a modified form at two different scales to extract wide and thin vessel enhanced images separately. Otsu thresholding has been further applied in a novel way to classify vessel and non-vessel pixels from both enhanced images. Finally, postprocessing steps has been used to eliminate the unwanted region/segment, non-vessel pixels, disease abnormalities and noise, to obtain a final segmented image. The proposed technique has been analyzed on the openly accessible DRIVE (Digital Retinal Images for Vessel Extraction) and STARE (STructured Analysis of the REtina) databases along with the ground truth data that has been precisely marked by the experts. PMID:27441646

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

    PubMed

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

    2012-09-01

    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

  14. Scaffold-free, Human Mesenchymal Stem Cell-Based Tissue Engineered Blood Vessels

    PubMed Central

    Jung, Youngmee; Ji, HaYeun; Chen, Zaozao; Fai Chan, Hon; Atchison, Leigh; Klitzman, Bruce; Truskey, George; Leong, Kam W.

    2015-01-01

    Tissue-engineered blood vessels (TEBV) can serve as vascular grafts and may also play an important role in the development of organs-on-a-chip. Most TEBV construction involves scaffolding with biomaterials such as collagen gel or electrospun fibrous mesh. Hypothesizing that a scaffold-free TEBV may be advantageous, we constructed a tubular structure (1 mm i.d.) from aligned human mesenchymal cell sheets (hMSC) as the wall and human endothelial progenitor cell (hEPC) coating as the lumen. The burst pressure of the scaffold-free TEBV was above 200 mmHg after three weeks of sequential culture in a rotating wall bioreactor and perfusion at 6.8 dynes/cm2. The interwoven organization of the cell layers and extensive extracellular matrix (ECM) formation of the hMSC-based TEBV resembled that of native blood vessels. The TEBV exhibited flow-mediated vasodilation, vasoconstriction after exposure to 1 μM phenylephrine and released nitric oxide in a manner similar to that of porcine femoral vein. HL-60 cells attached to the TEBV lumen after TNF-α activation to suggest a functional endothelium. This study demonstrates the potential of a hEPC endothelialized hMSC-based TEBV for drug screening. PMID:26456074

  15. Discrimination between two different grades of human glioma based on blood vessel infrared spectral imaging.

    PubMed

    Wehbe, Katia; Forfar, Isabelle; Eimer, Sandrine; Cinque, Gianfelice

    2015-09-01

    Gliomas are brain tumours classified into four grades with increasing malignancy from I to IV. The development and the progression of malignant glioma largely depend on the tumour vascularization. Due to their tissue heterogeneity, glioma cases can be difficult to classify into a specific grade using the gold standard of histological observation, hence the need to base classification on a quantitative and reliable analytical method for accurately grading the disease. Previous works focused specifically on vascularization study by Fourier transform infrared (FTIR) spectroscopy, proving this method to be a way forward to detect biochemical changes in the tumour tissue not detectable by visual techniques. In this project, we employed FTIR imaging using a focal plane array (FPA) detector and globar source to analyse large areas of glioma tumour tissue sections via molecular fingerprinting in view of helping to define markers of the tumour grade. Unsupervised multivariate analysis (hierarchical cluster analysis and principal component analysis) of blood vessel spectral data, retrieved from the FPA images, revealed the fine structure of the borderline between two areas identified by a pathologist as grades III and IV. Spectroscopic indicators are found capable of discriminating different areas in the tumour tissue and are proposed as biomolecular markers for potential future use of grading gliomas. Graphical Abstract Infrared imaging of glioma blood vessels provides a means to revise the pathologists' line of demarcation separating grade III (GIII) from grade IV (GIV) parts. PMID:26168973

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

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

    PubMed Central

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

    2014-01-01

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

  19. Cuff for Blood-Vessel Pressure Measurements

    NASA Technical Reports Server (NTRS)

    Shimizu, M.

    1982-01-01

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

  20. Improved automated optic cup segmentation based on detection of blood vessel bends in retinal fundus images.

    PubMed

    Hatanaka, Yuji; Nagahata, Yuuki; Muramatsu, Chisako; Okumura, Susumu; Ogohara, Kazunori; Sawada, Akira; Ishida, Kyoko; Yamamoto, Tetsuya; Fujita, Hiroshi

    2014-01-01

    Glaucoma is a leading cause of permanent blindness. Retinal imaging is useful for early detection of glaucoma. In order to evaluate the presence of glaucoma, ophthalmologists may determine the cup and disc areas and diagnose glaucoma using a vertical optic cup-to-disc (C/D) ratio and a rim-to-disc (R/D) ratio. Previously we proposed a method to determine cup edge by analyzing a vertical profile of pixel values, but this method provided a cup edge smaller than that of an ophthalmologist. This paper describes an improved method using the locations of the blood vessel bends. The blood vessels were detected by a concentration feature determined from the density gradient. The blood vessel bends were detected by tracking the blood vessels from the disc edge to the primary cup edge, which was determined by our previous method. Lastly, the vertical C/D ratio and the R/D ratio were calculated. Using forty-four images, including 32 glaucoma images, the AUCs of both the vertical C/D ratio and R/D ratio by this proposed method were 0.966 and 0.936, respectively. PMID:25569913

  1. Mass Spectrometry and Antibody-Based Characterization of Blood Vessels from Brachylophosaurus canadensis.

    PubMed

    Cleland, Timothy P; Schroeter, Elena R; Zamdborg, Leonid; Zheng, Wenxia; Lee, Ji Eun; Tran, John C; Bern, Marshall; Duncan, Michael B; Lebleu, Valerie S; Ahlf, Dorothy R; Thomas, Paul M; Kalluri, Raghu; Kelleher, Neil L; Schweitzer, Mary H

    2015-12-01

    Structures similar to blood vessels in location, morphology, flexibility, and transparency have been recovered after demineralization of multiple dinosaur cortical bone fragments from multiple specimens, some of which are as old as 80 Ma. These structures were hypothesized to be either endogenous to the bone (i.e., of vascular origin) or the result of biofilm colonizing the empty osteonal network after degradation of original organic components. Here, we test the hypothesis that these structures are endogenous and thus retain proteins in common with extant archosaur blood vessels that can be detected with high-resolution mass spectrometry and confirmed by immunofluorescence. Two lines of evidence support this hypothesis. First, peptide sequencing of Brachylophosaurus canadensis blood vessel extracts is consistent with peptides comprising extant archosaurian blood vessels and is not consistent with a bacterial, cellular slime mold, or fungal origin. Second, proteins identified by mass spectrometry can be localized to the tissues using antibodies specific to these proteins, validating their identity. Data are available via ProteomeXchange with identifier PXD001738. PMID:26595531

  2. Extraction of liver volumetry based on blood vessel from the portal phase CT dataset

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    At liver surgery planning stage, the liver volumetry would be essential for surgeons. Main problem at liver extraction is the wide variability of livers in shapes and sizes. Since, hepatic blood vessels structure varies from a person to another and covers liver region, the present method uses that information for extraction of liver in two stages. The first stage is to extract abdominal blood vessels in the form of hepatic and nonhepatic blood vessels. At the second stage, extracted vessels are used to control extraction of liver region automatically. Contrast enhanced CT datasets at only the portal phase of 50 cases is used. Those data include 30 abnormal livers. A reference for all cases is done through a comparison of two experts labeling results and correction of their inter-reader variability. Results of the proposed method agree with the reference at an average rate of 97.8%. Through application of different metrics mentioned at MICCAI workshop for liver segmentation, it is found that: volume overlap error is 4.4%, volume difference is 0.3%, average symmetric distance is 0.7 mm, Root mean square symmetric distance is 0.8 mm, and maximum distance is 15.8 mm. These results represent the average of overall data and show an improved accuracy compared to current liver segmentation methods. It seems to be a promising method for extraction of liver volumetry of various shapes and sizes.

  3. [Pulmonary blood vessels in goats].

    PubMed

    Roos, H; Hegner, K; Vollmerhaus, B

    1999-05-01

    The blood vessels in the lung of the goat, which until now have received little attention, are described in detail for the first time. With regard to the segments of the lung, blood vessels are bronchovascular units in the lobi craniales, lobus medius and lobus accessorius, but bronchoartery units in the lobi caudales. We investigated the types of branches of the Aa. pulmonales dextra et sinistra, the inter- and intraspecific principles of the outlet of the pulmonary veins and the importance of bronchopulmonary segmentation of the lungs. PMID:10386009

  4. BPC 157 and blood vessels.

    PubMed

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

    2014-01-01

    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

  5. Accuracy and precision of MR blood oximetry based on the long paramagnetic cylinder approximation of large vessels.

    PubMed

    Langham, Michael C; Magland, Jeremy F; Epstein, Charles L; Floyd, Thomas F; Wehrli, Felix W

    2009-08-01

    An accurate noninvasive method to measure the hemoglobin oxygen saturation (%HbO(2)) of deep-lying vessels without catheterization would have many clinical applications. Quantitative MRI may be the only imaging modality that can address this difficult and important problem. MR susceptometry-based oximetry for measuring blood oxygen saturation in large vessels models the vessel as a long paramagnetic cylinder immersed in an external field. The intravascular magnetic susceptibility relative to surrounding muscle tissue is a function of oxygenated hemoglobin (HbO(2)) and can be quantified with a field-mapping pulse sequence. In this work, the method's accuracy and precision was investigated theoretically on the basis of an analytical expression for the arbitrarily oriented cylinder, as well as experimentally in phantoms and in vivo in the femoral artery and vein at 3T field strength. Errors resulting from vessel tilt, noncircularity of vessel cross-section, and induced magnetic field gradients were evaluated and methods for correction were designed and implemented. Hemoglobin saturation was measured at successive vessel segments, differing in geometry, such as eccentricity and vessel tilt, but constant blood oxygen saturation levels, as a means to evaluate measurement consistency. The average standard error and coefficient of variation of measurements in phantoms were <2% with tilt correction alone, in agreement with theory, suggesting that high accuracy and reproducibility can be achieved while ignoring noncircularity for tilt angles up to about 30 degrees . In vivo, repeated measurements of %HbO(2) in the femoral vessels yielded a coefficient of variation of less than 5%. In conclusion, the data suggest that %HbO(2) can be measured reproducibly in vivo in large vessels of the peripheral circulation on the basis of the paramagnetic cylinder approximation of the incremental field. PMID:19526517

  6. Heart and Blood Vessels in Marfan Syndrome

    MedlinePlus

    ... Lungs Teeth Skin Current Research Heart and Blood Vessels Problems with the heart and blood vessels are common – and can be very serious – in ... these problems affects the aorta, the main blood vessel carrying blood from the heart to the rest ...

  7. Probe Follower for Moving Blood Vessels

    NASA Technical Reports Server (NTRS)

    Frazer, R. E.; Andrews, T. W.

    1985-01-01

    Probes track vessel expansion and contraction with minimal perturbation. Nozzle back-pressure changes at cuff on blood vessel basis for monitoring position of probe in blood vessel. Fluidic amplifiers use signals to control three-axis servo that centers measuring probe between sensing-nozzle pairs at cuff.

  8. When Blood Vessels Bulge: All About Aneurysms

    MedlinePlus

    ... Vessels Bulge When Blood Vessels Bulge All About Aneurysms An aneurysm—a balloon-like bulge in an artery—can ... for years without causing any symptoms. But an aneurysm is a silent threat to your health. If ...

  9. Photoacoustic determination of blood vessel diameter

    NASA Astrophysics Data System (ADS)

    Kolkman, Roy G. M.; Klaessens, John H. G. M.; Hondebrink, Erwin; Hopman, Jeroen C. W.; de Mul, Frits F. M.; Steenbergen, Wiendelt; Thijssen, Johan M.; van Leeuwen, Ton G.

    2004-10-01

    A double-ring sensor was applied in photoacoustic tomographic imaging of artificial blood vessels as well as blood vessels in a rabbit ear. The peak-to-peak time (tgrpp) of the laser (1064 nm) induced pressure transient was used to estimate the axial vessel diameter. Comparison with the actual vessel diameter showed that the diameter could be approximated by 2ctgrpp, with c the speed of sound in blood. Using this relation, the lateral diameter could also precisely be determined. In vivo imaging and monitoring of changes in vessel diameters was feasible. Finally, acoustic time traces were recorded while flushing a vessel in the rabbit ear with saline, which proved that the main contribution to the laser-induced pressure transient is caused by blood inside the vessel and that the vessel wall gives only a minor contribution.

  10. Purinergic transmission in blood vessels.

    PubMed

    Ralevic, Vera; Dunn, William R

    2015-09-01

    There are nineteen different receptor proteins for adenosine, adenine and uridine nucleotides, and nucleotide sugars, belonging to three families of G protein-coupled adenosine and P2Y receptors, and ionotropic P2X receptors. The majority are functionally expressed in blood vessels, as purinergic receptors in perivascular nerves, smooth muscle and endothelial cells, and roles in regulation of vascular contractility, immune function and growth have been identified. The endogenous ligands for purine receptors, ATP, ADP, UTP, UDP and adenosine, can be released from different cell types within the vasculature, as well as from circulating blood cells, including erythrocytes and platelets. Many purine receptors can be activated by two or more of the endogenous ligands. Further complexity arises because of interconversion between ligands, notably adenosine formation from the metabolism of ATP, leading to complex integrated responses through activation of different subtypes of purine receptors. The enzymes responsible for this conversion, ectonucleotidases, are present on the surface of smooth muscle and endothelial cells, and may be coreleased with neurotransmitters from nerves. What selectivity there is for the actions of purines/pyrimidines comes from differential expression of their receptors within the vasculature. P2X1 receptors mediate the vasocontractile actions of ATP released as a neurotransmitter with noradrenaline (NA) from sympathetic perivascular nerves, and are located on the vascular smooth muscle adjacent to the nerve varicosities, the sites of neurotransmitter release. The relative contribution of ATP and NA as functional cotransmitters varies with species, type and size of blood vessel, neuronal firing pattern, the tone/pressure of the blood vessel, and in ageing and disease. ATP is also a neurotransmitter in non-adrenergic non-cholinergic perivascular nerves and mediates vasorelaxation via smooth muscle P2Y-like receptors. ATP and adenosine can act as

  11. Automated measurement of retinal blood vessel tortuosity

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  12. Zinc oxide nanoflowers make new blood vessels

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  14. Ultrasound-based Measurement of Molecular Marker Concentration in Large Blood Vessels: A Feasibility Study

    PubMed Central

    Wang, Shiying; Mauldin, F. William; Klibanov, Alexander L.; Hossack, John A.

    2014-01-01

    Ultrasound molecular imaging has demonstrated efficacy in pre-clinical studies for cancer and cardiovascular inflammation. However, these techniques often require lengthy protocols due to waiting periods or additional control microbubble injections. Moreover, they are not capable of quantifying molecular marker concentration in human tissue environments that exhibit variable attenuation and propagation path lengths. Our group recently investigated a modulated Acoustic Radiation Force (ARF)-based imaging sequence, which was demonstrated to detect targeted adhesion independent of control measurements. In the present study, this sequence was tested against various experimental parameters to determine feasibility for quantitative measurements of molecular marker concentration. Results demonstrated that measurements obtained from the sequence (residual-to-saturation ratio, Rresid) were independent of acoustic pressure and attenuation (p> 0.13, n = 10)when acoustic pressures were sufficiently low. The Rresid parameter exhibited a linear relationship with measured molecular marker concentration (R2> 0.94). Consequently, feasibility was demonstrated in vitro, for quantification of molecular marker concentration in large vessels using a modulated ARF-based sequence. Moreover, these measurements were independent of absolute acoustic reflection amplitude and used short imaging protocols(3 min) without control measurements. PMID:25308943

  15. Designer blood vessels and therapeutic revascularization

    PubMed Central

    Berglund, Joseph D; Galis, Zorina S

    2003-01-01

    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

  16. Tianma modulates blood vessel tonicity.

    PubMed

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

    2012-01-01

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

  17. Blood vessel formation and function in bone.

    PubMed

    Sivaraj, Kishor K; Adams, Ralf H

    2016-08-01

    In addition to their conventional role as a conduit system for gases, nutrients, waste products or cells, blood vessels in the skeletal system play active roles in controlling multiple aspects of bone formation and provide niches for hematopoietic stem cells that reside within the bone marrow. In addition, recent studies have highlighted roles for blood vessels during bone healing. Here, we provide an overview of the architecture of the bone vasculature and discuss how blood vessels form within bone, how their formation is modulated, and how they function during development and fracture repair. PMID:27486231

  18. Computer Analysis of Eye Blood-Vessel Images

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  19. Method of assessing blood oxygenation in microcirculation vessels based on Doppler approach

    NASA Astrophysics Data System (ADS)

    Sokolov, Vladimir G.; Korsi, Larissa V.; Egorov, Sergei Y.

    2001-06-01

    Combination of laser Doppler flowmetry and pulse oximetry methods allows for the direct assessment of oxygen supply to tissues at the microcirculatory level, namely, in that part of the vascular network where the transcapillary exchange takes place that is responsible for saturating tissues with oxygen. The microcirculation system comprises arterial and venous microvascular parts that differ in blood flow velocities. Frequency separation of the photodetector signal components related to different velocity ranges makes possible to distinguish the hemodynamic processes in these two parts of the microvascular system. Moreover, numerous studies of collective oscillatory processes in hemodynamics reveal that cardio-oscillations are more pronounced in arterioles, whereas venous hemodynamics is mostly influenced by the breath rhythm. Taking account of the above phenomena allows developing a signal-filtration system for separate characterization of blood-oxygenation states in arterial and venous blood flows. Light absorbance in the skin depends on both light wavelength and blood-oxygenation level. Processing the signals obtained with a two-channel dual-wavelength (630 and 1115 nm) laser Doppler flowmeter provides information about blood oxygenation levels at the entrance and exit of the microvascular system and allows assessing the specific levels of oxygenation levels at the entrance and exit of the microvascular system and allows assessing the specific levels of oxygen consumption in tissues. In particular, this approach allows revealing pathogenic processes resulting from hyper- and hypo-oxygenation in tissues. For instance, rapidly growing malignant tumors are characterized by intensive metabolism, rapid formation of capillaries, and active transcapillary oxygen exchange that results in higher level of oxygen diffusion into tissue, while the level of oxygen is lowered in the microvascular veins.

  20. Quantification of blood vessel calibre in retinal images of multi-ethnic school children using a model based approach.

    PubMed

    Fraz, M M; Remagnino, P; Hoppe, A; Rudnicka, A R; Owen, C G; Whincup, P H; Barman, S A

    2013-01-01

    Changes and variation in retinal vessel width are related to vascular risk factors and prospectively related to cardiovascular disease in later life. Hence, assessment of vessel width may be a useful physio-marker and potential predictor of cardiovascular status. However, measurement of vessel calibre from retinal images is a challenging process to automate. This paper proposes an automated system to measure vessel calibre in retinal images, which is demonstrated in images of multi-ethnic school children. The diameter measurement is based on the detection of the centreline pixels from a vessel probability map image, determining the vessel orientation at these pixels, extracting the vessel segments and later using a two-dimensional model, which is optimized to fit various types of intensity profiles of vessel segments. The width is then estimated from parameters of the optimized model. The method is also quantitatively analyzed using monochromatic representations of different colour spaces. The algorithm is evaluated on a recently introduced public database CHASE_DB1, which is a subset of retinal images of multi-ethnic children from the Child Heart and Health Study in England (CHASE) dataset. Moreover, the precise estimation of retinal vascular widths is critical for epidemiologists to identify the risk factors. This work also introduces an interactive software tool for epidemiologists, with which retinal vessel calibre can be precisely marked. PMID:23410507

  1. `Sausage string' patterns in blood vessels at high blood pressures

    NASA Astrophysics Data System (ADS)

    Alstrøm, Preben; Eguíluz, Victor M.; Gustafsson, Finn; Holstein-Rathlou, Niels-Henrik

    A new Rayleigh-type instability is proposed to explain the `sausage-string' pattern of alternating constrictions and dialtations formed in blood vessels at high blood pressure conditions. Our theory involves the nonlinear stress-strain characteristics of the vessel wall, and provides predictions for the conditions under which the normal cylindrical geometry of a blood vessel becomes unstable. The theory explains key features observed experimentally, e.g. the limited occurrence of the sausage-string pattern to small arteries and large arterioles, and only in those with small wall-to-lumen ratios.

  2. Classification & Structure of Blood Vessels

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... return blood to the heart (veins). The primary function of capillaries is the ... cells. Capillary distribution varies with the metabolic activity of ...

  3. Improvement of retinal blood vessel detection using morphological component analysis.

    PubMed

    Imani, Elaheh; Javidi, Malihe; Pourreza, Hamid-Reza

    2015-03-01

    Detection and quantitative measurement of variations in the retinal blood vessels can help diagnose several diseases including diabetic retinopathy. Intrinsic characteristics of abnormal retinal images make blood vessel detection difficult. The major problem with traditional vessel segmentation algorithms is producing false positive vessels in the presence of diabetic retinopathy lesions. To overcome this problem, a novel scheme for extracting retinal blood vessels based on morphological component analysis (MCA) algorithm is presented in this paper. MCA was developed based on sparse representation of signals. This algorithm assumes that each signal is a linear combination of several morphologically distinct components. In the proposed method, the MCA algorithm with appropriate transforms is adopted to separate vessels and lesions from each other. Afterwards, the Morlet Wavelet Transform is applied to enhance the retinal vessels. The final vessel map is obtained by adaptive thresholding. The performance of the proposed method is measured on the publicly available DRIVE and STARE datasets and compared with several state-of-the-art methods. An accuracy of 0.9523 and 0.9590 has been respectively achieved on the DRIVE and STARE datasets, which are not only greater than most methods, but are also superior to the second human observer's performance. The results show that the proposed method can achieve improved detection in abnormal retinal images and decrease false positive vessels in pathological regions compared to other methods. Also, the robustness of the method in the presence of noise is shown via experimental result. PMID:25697986

  4. Videodensitometry for measuring blood vessel diameter.

    PubMed

    Hoornstra, K; Hanselman, J M; Holland, W P; De Wey Peters, G W; Zwamborn, A W

    1980-01-01

    A method employing a special computer for determining the internal diameters of blood vessels from photofluorographic image is described; in vitro and in vivo experiments are performed with the system. The amount of contrast medium injected is restricted to 4 times 3 ml, and it is possible to determine the diameter (in the range from 2 to 16 mm) at any place where blood vessels can be catheterized. In the in vivo experiments the maximum systematic error is +/-5 percent in the 7 to 8 mm range. PMID:7424549

  5. Diffuse light tomography to detect blood vessels using Tikhonov regularization

    NASA Astrophysics Data System (ADS)

    Kazanci, Huseyin O.; Jacques, Steven L.

    2016-04-01

    Detection of blood vessels within light-scattering tissues involves detection of subtle shadows as blood absorbs light. These shadows are diffuse but measurable by a set of source-detector pairs in a spatial array of sources and detectors on the tissue surface. The measured shadows can reconstruct the internal position(s) of blood vessels. The tomographic method involves a set of Ns sources and Nd detectors such that Nsd = Ns x Nd source-detector pairs produce Nsd measurements, each interrogating the tissue with a unique perspective, i.e., a unique region of sensitivity to voxels within the tissue. This tutorial report describes the reconstruction of the image of a blood vessel within a soft tissue based on such source-detector measurements, by solving a matrix equation using Tikhonov regularization. This is not a novel contribution, but rather a simple introduction to a well-known method, demonstrating its use in mapping blood perfusion.

  6. Blackworms, Blood Vessel Pulsations and Drug Effects.

    ERIC Educational Resources Information Center

    Lesiuk, Nalena M.; Drewes, Charles D.

    1999-01-01

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

  7. Imaging blood vessels in the zebrafish.

    PubMed

    Kamei, Makoto; Isogai, Sumio; Pan, Weijun; Weinstein, Brant M

    2010-01-01

    Understanding on the mechanisms of vascular branching morphogenesis has become a subject of enormous scientific and clinical interest. Zebrafish, which have small, accessible, transparent embryos and larvae, provides a unique living animal model to facilitating high-resolution imaging on ubiquitous and deep localization of vessels within embryo development and also in adult tissues. In this chapter, we have summarized various methods for vessel imaging in zebrafish, including in situ hybridization for vascular-specific genes, resin injection- or dye injection-based vessel visualization, and alkaline phosphatase staining. We also described detail protocols for live imaging of vessels by microangiography or using various transgenic zebrafish lines. PMID:21111213

  8. Avian Blood-Vessel Formation in Space

    NASA Technical Reports Server (NTRS)

    Lelkes, Peter I.

    1999-01-01

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

  9. An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells.

    PubMed

    Wang, Xue-Ying; Pei, Ying; Xie, Min; Jin, Zi-He; Xiao, Ya-Shi; Wang, Yang; Zhang, Li-Na; Li, Yan; Huang, Wei-Hua

    2015-02-21

    Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced. PMID:25565271

  10. Endothelium-dependent relaxation of blood vessels

    SciTech Connect

    Hynes, M.R.

    1987-01-01

    Dilation of blood vessels in response to a large number of agents has been shown to be dependent on an intact vascular endothelium. The present studies examine some aspects of endothelium-dependent vasodilation in blood vessels of the rabbit and rat. Using the rabbit ear artery and the subtype-selective muscarinic antagonist pirenzepine, muscarinic receptors of the endothelium and smooth muscle cells were shown to be of the low affinity M/sub 2/ subtype. Inhibition of (/sup 3/H)(-)quinuclidinyl benzilate was used to determine affinity for the smooth muscle receptors while antagonism of methacholine induced vasodilation yielded the endothelial cell receptor affinity. The effect of increasing age (1-27 months) on endothelium-dependent relaxation was studied in aortic rings, perfused tail artery and perfused mesenteric bed of the Fisher 344 rat. The influence of endothelium on contractile responses was examined using the perfused caudal artery.

  11. Perivascular cells in blood vessel regeneration.

    PubMed

    Wanjare, Maureen; Kusuma, Sravanti; Gerecht, Sharon

    2013-04-01

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

  12. Blood Vessel Segmentation of Fundus Images by Major Vessel Extraction and Subimage Classification.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Parhi, Keshab K

    2015-05-01

    This paper presents a novel three-stage blood vessel segmentation algorithm using fundus photographs. In the first stage, the green plane of a fundus image is preprocessed to extract a binary image after high-pass filtering, and another binary image from the morphologically reconstructed enhanced image for the vessel regions. Next, the regions common to both the binary images are extracted as the major vessels. In the second stage, all remaining pixels in the two binary images are classified using a Gaussian mixture model (GMM) classifier using a set of eight features that are extracted based on pixel neighborhood and first and second-order gradient images. In the third postprocessing stage, the major portions of the blood vessels are combined with the classified vessel pixels. The proposed algorithm is less dependent on training data, requires less segmentation time and achieves consistent vessel segmentation accuracy on normal images as well as images with pathology when compared to existing supervised segmentation methods. The proposed algorithm achieves a vessel segmentation accuracy of 95.2%, 95.15%, and 95.3% in an average of 3.1, 6.7, and 11.7 s on three public datasets DRIVE, STARE, and CHASE_DB1, respectively. PMID:25014980

  13. Photoacoustic removal of occlusions from blood vessels

    DOEpatents

    Visuri, Steven R.; Da Silva, Luiz B.; Celliers, Peter M.; London, Richard A.; Maitland, IV, Duncan J.; Esch, Victor C.

    2002-01-01

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

  14. Method and device for supporting blood vessels during anastomosis

    DOEpatents

    Doss, J.D.

    1985-05-20

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

  15. Hemoglobin alpha in the blood vessel wall

    PubMed Central

    Butcher, Joshua T.; Johnson, Tyler; Beers, Jody; Columbus, Linda; Isakson, Brant E

    2014-01-01

    Hemoglobin has been studied and well haracterized in red blood cells for over one hundred years. However, new work has indicated that the hemoglobin alpha subunit (Hbα) is also found within the blood vessel wall, where it appears to localize at the myoendothelial junction (MEJ) and plays a role in regulating nitric oxide (NO) signaling between endothelium and smooth muscle. This discovery has created a new paradigm for control of endothelial nitric oxide synthase activity, nitric oxide diffusion, and ultimately, control of vascular tone and blood pressure. This review will discuss the current knowledge of hemoglobin’s properties as a gas exchange molecule in the blood stream, and extrapolate the properties of Hbα biology to the MEJ signaling domain. Specifically, we propose that Hbα is present at the MEJ to regulate NO release and diffusion in a restricted physical space, which would have powerful implications for the regulation of blood flow in peripheral resistance arteries. PMID:24832680

  16. Quantitative analysis of blood vessel geometry

    NASA Astrophysics Data System (ADS)

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

    2001-07-01

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

  17. Fractal structures in stenoses and aneurysms in blood vessels

    PubMed Central

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

    2010-01-01

    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

  18. Photoacoustic imaging of blood vessel equivalent phantoms

    NASA Astrophysics Data System (ADS)

    Beard, Paul C.

    2002-06-01

    Various phantoms have been used to assess the ability of transmission mode photoacoustic imaging to visualize blood vessels. A Q switched Nd:YAG laser operating at 1.06micrometers was used as the pulsed excitation source. Detection of the photoacoustic signals was achieved by mechanically scanning a photodiode across the reflected output beam of a Fabry Perot polymer film ultrasound sensor to simulate 1D and 2D detector arrays. The depth profile of a 1.3mm thick polymer sheet ((mu) a=0.8mm-1) immersed to a depth of 2cm in an Intralipid scattering solution ((mu) s=1mm-1, (mu) a=0.03mm-1 was imaged using a 1D detector scan and a simple line-of-sight approach to image reconstruction. An arrangement comprising three 3 lines of PMMA tubing of internal diameter 62.5micrometers , arranged at different heights and filled with human blood, was immersed at depths of up to 7mm in the Intralipid solution. Using a radial backprojection algorithm, 2D and 3D images were reconstructed from 1D and 2D detector scans respectively. The vessels could be observed as high contrast features on the images. Lateral resolution, limited by the detector aperture was 0.33mm and the axial resolution was 0.15mm.

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

    PubMed Central

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

    2012-01-01

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

  20. Unsteady Flow in Stenotic Blood Vessels

    NASA Astrophysics Data System (ADS)

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

    2003-11-01

    Recent studies show that many heart attacks and strokes occur from sudden rupture of partially occluding atherosclerotic plaque rather than total vessel occlusion. Our goal is to understand how the mechanical forces induced by blood flow on specific plaque deposits makes them vulnerable to rupture. Models of severely stenotic carotid bifurcations are created from MR images and grids generated for 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

  1. Prevent Diabetes Problems: Keep Your Heart and Blood Vessels Healthy

    MedlinePlus

    ... Lung and Blood Institute American Diabetes Association JDRF Diabetes Disease Organizations Many organizations provide support to patients ... PDF, 293 KB). Alternate Language URL Español Prevent diabetes problems: Keep your heart and blood vessels healthy ...

  2. Pre-Operative Image-based Segmentation of the Cranial Nerves and Blood Vessels in Microvascular Decompression: Can we Prevent Unnecessary Explorations?

    PubMed Central

    Dolati, P; Golby, A; Eichberg, D; Abolfotoh, M; Dunn, IF; Mukundan, S; Hulou, MM; Al-Mefty, O

    2016-01-01

    Objectives This study was conducted to validate the accuracy of image-based pre-operative segmentation using the gold standard endoscopic and microscopic findings for localization and pre-operative diagnosis of the offensive vessel. Patients and Methods Fourteen TN and 6 HS cases were randomly selected. All patients had 3T MRI, which included thin-sectioned 3D space T2, 3D Time of Flight and MPRAGE Sequences. Imaging sequences were loaded in BrainLab iPlanNet and fused. Individual segmentation of the affected cranial nerves and the compressing vascular structure was performed by a neurosurgeon, and the results were compared with the microscopic and endoscopic findings by two blinded neurosurgeons. For each case, at least three neurovascular landmarks were targeted. Each segmented neurovascular element was validated by manual placement of the navigation probe over each target, and errors of localization were measured in mm. Results All patients underwent retro-sigmoid craniotomy and MVD using both microscope and endoscope. Based on image segmentation, the compressing vessel was identified in all cases except one, which was also negative intraoperatively. Perfect correspondence was found between image-based segmentation and endoscopic and microscopic images and videos (Dice coefficient of 1). Measurement accuracy was 0.45+/-0.21 mm (mean +/-SD). Conclusion Image-based segmentation is a promising method for pre-operative identification and localization of offending blood vessels causing HFS and TN. Using this method may prevent some unnecessary explorations on especially atypical cases with no vascular contacts. However, negative pre-operative image segmentation may not preclude one from exploration in classic cases of TN or HFS. A multicenter study with larger number of cases is recommended. PMID:26476700

  3. Role of neural guidance signals in blood vessel navigation.

    PubMed

    Autiero, Monica; De Smet, Frederik; Claes, Filip; Carmeliet, Peter

    2005-02-15

    Despite the tremendous progress achieved in both vasculogenesis and angiogenesis in the last decade, little is still known about the molecular mechanisms underlying the pathfinding of blood vessels during their formation. However, emerging evidence shows that different axonal guidance cues, including members of the Slit and semaphorin families, are also involved in the blood vessel guidance, suggesting that blood vessels and nerves share common mechanisms in choosing and following specific paths to reach their respective targets. These promising findings open novel avenues not only in vascular biology but also in therapeutic angiogenesis. Indeed, the identification of new molecules involved in the guidance of blood vessels may be helpful in designing angiogenic strategies, which would insure both the formation of new blood vessels and their guidance into an organized and coordinated network. PMID:15664389

  4. Glucose metabolism in diabetic blood vessels

    SciTech Connect

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

    1986-03-05

    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.

  5. Tumour angiogenesis-Origin of blood vessels.

    PubMed

    Krishna Priya, S; Nagare, R P; Sneha, V S; Sidhanth, C; Bindhya, S; Manasa, P; Ganesan, T S

    2016-08-15

    The conventional view of tumour vascularization is that tumours acquire their blood supply from neighbouring normal stroma. Additional methods of tumour vascularization such as intussusceptive angiogenesis, vasculogenic mimicry, vessel co-option and vasculogenesis have been demonstrated to occur. However, the origin of the endothelial cells and pericytes in the tumour vasculature is not fully understood. Their origin from malignant cells has been shown indirectly in lymphoma and neuroblastoma by immuno-FISH experiments. It is now evident that tumours arise from a small population of cells called cancer stem cells (CSCs) or tumour initiating cells. Recent data suggest that a proportion of tumour endothelial cells arise from cancer stem cells in glioblastoma. This was demonstrated both in vitro and in vivo. The analysis of chromosomal abnormalities in endothelial cells showed identical genetic changes to those identified in tumour cells. However, another report contradicted these results from the earlier studies in glioblastoma and had shown that CSCs give rise to pericytes and not endothelial cells. The main thrust of this review is the critical analysis of the conflicting data from different studies and the remaining questions in this field of research. The mechanism by which this phenomenon occurs is also discussed in detail. The transdifferentiation of CSCs to endothelial cells/pericytes has many implications in the progression and metastasis of the tumours and hence it would be a novel target for antiangiogenic therapy. PMID:26934471

  6. Silk fibroin microtubes for blood vessel engineering.

    PubMed

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

    2007-12-01

    Currently available synthetic grafts demonstrate moderate success at the macrovascular level, but fail at the microvascular scale (<6mm inner diameter). We report on the development of silk fibroin microtubes for blood vessel repair with several advantages over existing scaffold materials/designs. These microtubes were prepared by dipping straight lengths of stainless steel wire into aqueous silk fibroin, where the addition of poly(ethylene oxide) (PEO) enabled control of microtube porosity. The microtube properties were characterized in terms of pore size, burst strength, protein permeability, enzymatic degradation, and cell migration. Low porosity microtubes demonstrated superior mechanical properties in terms of higher burst pressures, but displayed poor protein permeability; whereas higher porosity tubes had lower burst strengths but increased permeability and enhanced protein transport. The microtubes also exhibited cellular barrier functions as low porosity tubes prevented outward migration of GFP-transduced HUVECs, while the high porosity microtubes allowed a few cells per tube to migrate outward during perfusion. When combined with the biocompatible and suturability features of silk fibroin, these results suggest that silk microtubes, either implanted directly or preseeded with cells, are an attractive biomaterial for microvascular grafts. PMID:17727944

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

    SciTech Connect

    Akabani, G. ); Poston, J.W. . Dept. of Nuclear Engineering)

    1991-05-01

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

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

    SciTech Connect

    Akabani, G.; Poston, J.W. Sr. )

    1991-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Bose, Sayan; Banerjee, Moloy

    2015-01-01

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

  10. Distinct bone marrow blood vessels differentially regulate haematopoiesis.

    PubMed

    Itkin, Tomer; Gur-Cohen, Shiri; Spencer, Joel A; Schajnovitz, Amir; Ramasamy, Saravana K; Kusumbe, Anjali P; Ledergor, Guy; Jung, Yookyung; Milo, Idan; Poulos, Michael G; Kalinkovich, Alexander; Ludin, Aya; Kollet, Orit; Shakhar, Guy; Butler, Jason M; Rafii, Shahin; Adams, Ralf H; Scadden, David T; Lin, Charles P; Lapidot, Tsvee

    2016-04-21

    Bone marrow endothelial cells (BMECs) form a network of blood vessels that regulate both leukocyte trafficking and haematopoietic stem and progenitor cell (HSPC) maintenance. However, it is not clear how BMECs balance these dual roles, and whether these events occur at the same vascular site. We found that mammalian bone marrow stem cell maintenance and leukocyte trafficking are regulated by distinct blood vessel types with different permeability properties. Less permeable arterial blood vessels maintain haematopoietic stem cells in a low reactive oxygen species (ROS) state, whereas the more permeable sinusoids promote HSPC activation and are the exclusive site for immature and mature leukocyte trafficking to and from the bone marrow. A functional consequence of high permeability of blood vessels is that exposure to blood plasma increases bone marrow HSPC ROS levels, augmenting their migration and differentiation, while compromising their long-term repopulation and survival. These findings may have relevance for clinical haematopoietic stem cell transplantation and mobilization protocols. PMID:27074509

  11. Vasodilator effect of nicorandil on retinal blood vessels in rats.

    PubMed

    Ogawa, Naoto; Saito, Maki; Mori, Asami; Sakamoto, Kenji; Kametaka, Sokichi; Nakahara, Tsutomu; Ishii, Kunio

    2007-07-01

    We examined the effect of nicorandil on retinal blood vessels in rats in vivo. Male Wistar rats (8 to 10 weeks old) were anaesthetised with thiobutabarbital (120 mg/kg, intraperitoneal). Fundus images were captured with a digital camera that was equipped with a special objective lens. Diameters of retinal blood vessels were measured with a personal computer. Nicorandil (1-300 microg kg(-1) min(-1), intravenous [i.v.]) increased diameters of retinal blood vessels and decreased systemic blood pressure in a dose-dependent manner. Both responses to nicorandil were attenuated by glibenclamide (20 mg/kg, i.v.), an adenosine triphosphate (ATP)-dependent K(+) (K(ATP)) channel blocker. On the other hand, indomethacin (5 mg/kg, i.v.), a cyclooxygenase inhibitor, attenuated the vasodilation of retinal blood vessels, but not depressor response, to nicorandil and sodium nitroprusside. Pinacidil (1-300 microg kg(-1) min(-1), i.v.), a K(ATP) channel opener, also dilated retinal blood vessels and decreased systemic blood pressure. The responses to pinacidil were prevented by glibenclamide, but not by indomethacin. The vasodilation of retinal arteriole, but not depressor response, to sodium nitroprusside (1-30 microg kg(-1) min(-1), i.v.), a nitric oxide donor, was attenuated by indomethacin. These results suggest that nicorandil dilates retinal blood vessels through opening of K(ATP) channels and production of prostaglandins that are probably generated by nitric oxide. PMID:17525845

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

    NASA Astrophysics Data System (ADS)

    Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

    2007-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    PubMed

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

    2014-01-01

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

  15. Effects of hypoxia on vertebrate blood vessels.

    PubMed

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

    2008-03-01

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

  16. Fluid Structure Modelling of Blood Flow in Vessels.

    PubMed

    Moatamedi, M; Souli, M; Al-Bahkali, E

    2014-12-01

    This paper describes the capabilities of fluid structure interaction based multi-physics numerical modelling in solving problems related to vascular biomechanics. In this research work, the onset of a pressure pulse was simulated at the entrance of a three dimensional straight segment of the blood vessel like circular tube and the resulting dynamic response in the form of a propagating pulse wave through the wall was analysed and compared. Good agreement was found between the numerical results and the theoretical description of an idealized artery. Work has also been done on implementing the material constitutive models specific for vascular applications. PMID:26336693

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

    SciTech Connect

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

    1989-08-01

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

  18. 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...

  19. Development of blood vessel searching system for HMS

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  20. Photoacoustic monitoring and imaging of blood vessel size in vivo

    NASA Astrophysics Data System (ADS)

    Kolkman, Roy G. M.; Klaessens, John H. G. M.; Hondebrink, Erwin; Hopman, Jeroen C. W.; Steenbergen, Wiendelt; van Leeuwen, Ton G.; Thijssen, Johan M.; de Mul, Frits F. M.

    2003-06-01

    A double-ring photoacoustic sensor to image and monitor blood content in tissue has been developed. This sensor has a very small opening angle. Using this sensor we are able to image artifical blood vessels, as well as vessels in a rabbit ear. Furthermore, the feasibility of in vivo imaging is demonstrated with a photoacoustic reconstruction of the joining of two palmar veins a few centimeter proximal to the wrist in a human arm.

  1. Development of a blood vessel searching device for HMS

    NASA Astrophysics Data System (ADS)

    Kuroda, Tatsuro; Uenoya, Toshiyuki; Tsuchiya, Kazuyoshi; Uetsuji, Yasutomo; Nakamachi, Eiji

    2007-12-01

    In this study, an automatic blood vessel searching system (BVSS) is newly developed, which is built in the health monitoring system (HMS) and the drug delivery system (DDS) to extract the blood, evaluates the blood sugar level and injects the insulin for the diabetic patients. Main subjects of our BVSS development are 1) a transmittance photo imaging of the finger by using the LED light as a near-infrared light source with peak wave length of 870 nm, and 2) an image processing to detect the location of the center of the blood vessel cross section. The sharp edge focus method was applied in our BVSS to detect the depth of blood vessel. We carried out experiments by using blood vessel phantoms, which consist of an artificial cylindrical blood vessel and skin tissue, which are made of the teflon tube and the silicone rubber. The teflon tube has the size of 0.6 mm in diameter and is filled with the human blood. The experimental results demonstrated that the estimated depth, which is obtained by image analysis corresponding to given depths, shows a good agreement with the real values, and consequently the availability of our BVSS is confirmed.

  2. A multilayered microfluidic blood vessel-like structure

    PubMed Central

    Hasan, Anwarul; Paul, Arghya; Memic, Adnan; Khademhosseini, Ali

    2016-01-01

    There is an immense need for tissue engineered blood vessels. However, current tissue engineering approaches still lack the ability to build native blood vessel-like perfusable structures with multi-layered vascular walls. This paper demonstrated a new method to fabricate tri-layer biomimetic blood vessel-like structures on a microfluidic platform using photocrosslinkable gelatin hydrogel. The presented method enables fabrication of physiological blood vessel-like structures with mono-, bi- or tri-layer vascular walls. The diameter of the vessels, the total thickness of the vessel wall and the thickness of each individual layer of the wall were independently controlled. The developed fabrication process is a simple and rapid method, allowing the physical fabrication of the vascular structure in minutes, and the formation of a vascular endothelial cell layer inside the vessels in 3–5 days. The fabricated vascular constructs can potentially be used in numerous applications including drug screening, development of in vitro models for cardiovascular diseases and/or cancer metastasis, and study of vascular biology and mechanobiology. PMID:26256481

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  4. Visualization of deep blood vessels in speckle imaging using homogeneity measurement of the co-occurrence matrix

    NASA Astrophysics Data System (ADS)

    Arias-Cruz, Jose A.; Perez-Corona, Cruz E.; Peregrina-Barreto, Hayde; Ramos-Garcia, Ruben; Ramirez-San-Juan, Julio Cesar

    2015-08-01

    The blood flow velocity optical monitoring techniques, such as laser speckle velocimetry, are attractive due its noninvasive character, but they are limited to superficial blood vessels. The visualization of deep blood vessel is difficult because of the highly scattering coefficient of the biological tissue. There are some techniques that allow the visualization of deep blood vessels, for example: optical clearing, Magnetomotive Laser Speckle Imaging and Pulsed Photo-Thermal Radiometry, unfortunately these techniques use an external agent to improve the visualization of blood vessels. In this work we improve the visualization and location of in-vitro deep blood vessels by speckle image processing without an external agents. The proposed methodology is based in a homogeneity measurement of the co-occurrence matrix by the direct processing of the speckle image. Our technique is able to determine the edges of a deep blood vessel and therefore improves its visualization.

  5. Visualisation and stereological assessment of blood and lymphatic vessels.

    PubMed

    Lokmic, Zerina; Mitchell, Geraldine M

    2011-06-01

    The physiological processes involved in tissue development and regeneration also include the parallel formation of blood and lymphatic vessel circulations which involves their growth, maturation and remodelling. Both vascular systems are also frequently involved in the development and progression of pathological conditions in tissues and organs. The blood vascular system circulates oxygenated blood and nutrients at appropriate physiological levels for tissue survival, and efficiently removes all waste products including carbon dioxide. This continuous network consists of the heart, aorta, arteries, arterioles, capillaries, post-capillary venules, venules, veins and vena cava. This system exists in an interstitial environment together with the lymphatic vascular system, including lymph nodes, which aids maintenance of body fluid balance and immune surveillance. To understand the process of vascular development, vascular network stability, remodelling and/or regression in any research model under any experimental conditions, it is necessary to clearly and unequivocally identify and quantify all elements of the vascular network. By utilising stereological methods in combination with cellular markers for different vascular cell components, it is possible to estimate parameters such as surface density and surface area of blood vessels, length density and length of blood vessels as well as absolute vascular volume. This review examines the current strategies used to visualise blood vessels and lymphatic vessels in two- and three-dimensions and the basic principles of vascular stereology used to quantify vascular network parameters. PMID:21472692

  6. NEURONAL ACTION ON THE DEVELOPING BLOOD VESSEL PATTERN

    PubMed Central

    James, Jennifer M.; Mukouyama, Yoh-suke

    2011-01-01

    The nervous system relies on a highly specialized network of blood vessels for development and neuronal survival. Recent evidence suggests that both the central and peripheral nervous systems (CNS and PNS) employ multiple mechanisms to shape the vascular tree to meet its specific metabolic demands, such as promoting nerve-artery alignment in the PNS or the development the blood brain barrier in the CNS. In this article we discuss how the nervous system directly influences blood vessel patterning resulting in neuro-vascular congruence that is maintained throughout development and in the adult. PMID:21978864

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

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

    SciTech Connect

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

    2013-07-31

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

  9. Brain blood vessel segmentation using line-shaped profiles

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

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

    PubMed

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

    2014-04-01

    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

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

    PubMed

    Ying, Huajun; Wang, Xing; Liu, Jyh-Charn

    2014-01-01

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

  12. [Injuries of the blood vessels of the neck].

    PubMed

    Vasiutkov, V Ia; Kiselev, V Ia; Evstifeev, L K; Cheliukov, V S

    1985-05-01

    The investigation of protocols of medicolegal examinations of victims of injuries of major blood vessels has shown that traumas of the neck vessels equal 8,8%. The clinical observation of 27 patients with injured vessels of the neck shows that the selection of correct methods of temporary arrest of hemorrhage at the place of the accident can save most victims, life. The main cause of death in such cases in ischemia of the brain, hemorrhagic shock, associated trauma of organs of the neck. PMID:3898528

  13. Customizable engineered blood vessels using 3D printed inserts.

    PubMed

    Pinnock, Cameron B; Meier, Elizabeth M; Joshi, Neeraj N; Wu, Bin; Lam, Mai T

    2016-04-15

    Current techniques for tissue engineering blood vessels are not customizable for vascular size variation and vessel wall thickness. These critical parameters vary widely between the different arteries in the human body, and the ability to engineer vessels of varying sizes could increase capabilities for disease modeling and treatment options. We present an innovative method for producing customizable, tissue engineered, self-organizing vascular constructs by replicating a major structural component of blood vessels - the smooth muscle layer, or tunica media. We utilize a unique system combining 3D printed plate inserts to control construct size and shape, and cell sheets supported by a temporary fibrin hydrogel to encourage cellular self-organization into a tubular form resembling a natural artery. To form the vascular construct, 3D printed inserts are adhered to tissue culture plates, fibrin hydrogel is deposited around the inserts, and human aortic smooth muscle cells are then seeded atop the fibrin hydrogel. The gel, aided by the innate contractile properties of the smooth muscle cells, aggregates towards the center post insert, creating a tissue ring of smooth muscle cells. These rings are then stacked into the final tubular construct. Our methodology is robust, easily repeatable and allows for customization of cellular composition, vessel wall thickness, and length of the vessel construct merely by varying the size of the 3D printed inserts. This platform has potential for facilitating more accurate modeling of vascular pathology, serving as a drug discovery tool, or for vessel repair in disease treatment. PMID:26732049

  14. Tumor Stroma, Tumor Blood Vessels, and Antiangiogenesis Therapy.

    PubMed

    Dvorak, Harold F

    2015-01-01

    Solid tumors generally require a vascularized connective tissue stroma if they are to grow beyond minimal size. They generate that stroma in part by secreting vascular endothelial growth factor (VEGF), a potent vascular permeability and angiogenic factor. Increased vascular permeability leads to deposition of a provisional fibrin stroma, which supports tumor, connective tissue, and inflammatory cell migration and plays an active role in the formation of mature vascularized stroma. Vascular endothelial growth factor-induced tumor blood vessels are heterogeneous, of at least 6 distinct types, and develop linearly over time. They include both angiogenic (mother vessels, glomeruloid microvascular proliferations, vascular malformations, capillaries) and arteriovenogenic (feeding arteries, draining veins) blood vessels. Attacking the tumor vasculature with drugs that target VEGF or its receptors (VEGFR) has come into vogue but has been less effective than had been hope for. One reason for this is that anti-VEGF/VEGFR therapy attacks only a subset of tumor blood vessels, the earliest to form. New targets on late-forming blood vessels such as feeding arteries would be useful in helping antivascular cancer therapy fulfill its promise. PMID:26222073

  15. New microembolus size estimator for peripheral blood vessels.

    PubMed

    Zmigrodzki, Jakub; Kaluzynski, Krzysztof

    2012-03-01

    Several factors affecting the power of Doppler scattered signal and, consequently, microembolus size estimation, may be eliminated when assessing the microembolus size via multiple measurements. A new microembolus size estimator is proposed based on the ratio of microembolus scattering cross-section in two directions and for two emission frequencies. Theoretical considerations indicate that the estimation of size of microembolic elements should be independent of the spatial distribution of the wave intensity, tissue attenuation and hardware factors. The simulation results indicate that this estimation only slightly depends on the material of the microembolus and acoustic properties of blood. The experimental results indicate that the accuracy of median size estimation increases with microembolus size. The measurement error is less than 27% for microemboli with median diameter larger than 360 μm. The method is constrained to the estimation of microembolus size in the vessels of extremities. PMID:22305059

  16. Higher blood vessel density in comparison to the lymphatic vessels in oral squamous cell carcinoma

    PubMed Central

    Maturana-Ramírez, Andrea; Espinoza, Iris; Reyes, Montserrat; Aitken, Juan Pablo; Aguayo, Francisco; Hartel, Steffen; Rojas-Alcayaga, Gonzalo

    2015-01-01

    Introduction: Oral squamous cell carcinoma (OSCC) is characterized by local invasion and the development of cervical metastasis. In the tongue, an association between the invasion of the lymphatic vessels and the development of metastasis in the regional lymph nodes has been demonstrated. Moreover, invasion of the blood vessels is associated with greater recurrence and poorer prognoses. Therefore, the presence and density of lymphatic and blood vessels in intra- and peritumoral tissues should play an important role in the progression, dissemination and metastasis of carcinomas. However, the evidence regarding OSCC is inconclusive. The aim of this study was to determine the comparison and association between the lymphatic (D2-40) and blood vessel (CD34) densities in intratumoral OSCC tissue. Materials and Methods: Thirty-seven cases diagnosed as OSCC between the years 2000 and 2008 were obtained from the Anatomic Pathology Service of the School of Dentistry, University of Chile. The immunohistochemical markers D2-40 and CD34 were used, and the densities (mm2) of lymphatic vessels (LVD) and blood vessels (BVD) in the intratumoral region were determined. The relationship between LVD and BVD values was evaluated. Results: There were significant association between the CD34 and D2-40 expression (rho=0.4, P<0.05) and between the LVD and the location in the tongue (P=0.019). The BVD was greater (128.0 vessels/mm2) than the LVD (42.9 vessels/mm2), and there was a positive correlation between the LVD and BVD. Conclusions: In OSCC, the BVD is greater than the LVD, and there is a moderate correlation between the two quantities. PMID:26722595

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  18. Tracing retinal blood vessels by matrix-forest theorem of directed graphs.

    PubMed

    Cheng, Li; De, Jaydeep; Zhang, Xiaowei; Lin, Feng; Li, Huiqi

    2014-01-01

    This paper aims to trace retinal blood vessel trees in fundus images. This task is far from being trivial as the crossover of vessels are commonly encountered in image-based vessel networks. Meanwhile it is often crucial to separate the vessel tree structures in applications such as diabetic retinopathy analysis. In this work, a novel directed graph based approach is proposed to cast the task as label propagation over directed graphs, such that the graph is to be partitioned into disjoint sub-graphs, or equivalently, each of the vessel trees is traced and separated from the rest of the vessel network. Then the tracing problem is addressed by making novel usage of the matrix-forest theorem in algebraic graph theory. Empirical experiments on synthetic as well as publicly available fundus image datasets demonstrate the applicability of our approach. PMID:25333171

  19. Acrolein generation stimulates hypercontraction in isolated human blood vessels

    SciTech Connect

    Conklin, D.J. . E-mail: dj.conklin@louisville.edu; Bhatnagar, A.; Cowley, H.R.; Johnson, G.H.; Trent, M.B.; Boor, P.J.

    2006-12-15

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

  20. Application of the Carreau viscosity model to the oscillatory flow in blood vessels

    NASA Astrophysics Data System (ADS)

    Tabakova, Sonia; Kutev, Nikolay; Radev, Stefan

    2015-11-01

    When studying the oscillatory flow in different types of blood vessels it is very important to know what type of the blood viscosity model has to be used. In general the blood viscosity is defined as a shear-thinning liquid, for which there exist different shear-dependent models, for example the Carreau model, which represents the viscosity as a non-linear function of the shear-rate. In some cases, however, the blood viscosity could be regarded as constant, i.e., the blood is treated as Newtonian fluid. The aim of the present work is to show theoretically and numerically some approximate limits of the Newtonian model application, when the blood vessel is assumed as a 2D straight tube. The obtained results are in agreement with other authors' numerical results based on similar blood viscosity models.

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    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.

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

    PubMed

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

    2008-01-01

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

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

    PubMed

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

    2013-01-01

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

  4. Wavelength dependence of the apparent diameter of retinal blood vessels.

    PubMed

    Park, Robert; Twietmeyer, Karen; Chipman, Russell; Beaudry, Neil; Salyer, David

    2005-04-01

    Imaging of retinal blood vessels may assist in the diagnosis and monitoring of diseases such as glaucoma, diabetic retinopathy, and hypertension. However, close examination reveals that the contrast and apparent diameter of vessels are dependent on the wavelength of the illuminating light. In this study multispectral images of large arteries and veins within enucleated swine eyes are obtained with a modified fundus camera by use of intravitreal illumination. The diameters of selected vessels are measured as a function of wavelength by cross-sectional analysis. A fixed scale with spectrally independent dimension is placed above the retina to isolate the chromatic effects of the imaging system and eye. Significant apparent differences between arterial and venous diameters are found, with larger diameters observed at shorter wavelengths. These differences are due primarily to spectral absorption in the cylindrical blood column. PMID:15813519

  5. Pattern Recognition Of Blood Vessel Networks In Ocular Fundus Images

    NASA Astrophysics Data System (ADS)

    Akita, K.; Kuga, H.

    1982-11-01

    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.

  6. H2S and Blood Vessels: An Overview.

    PubMed

    Yang, Guangdong; Wang, Rui

    2015-01-01

    The physiological and biomedical importance of hydrogen sulfide (H2S) has been fully recognized in the cardiovascular system as well as in the rest of the body. In blood vessels, cystathionine γ-lyase (CSE) is a major H2S-producing enzyme expressed in both smooth muscle and endothelium as well as periadventitial adipose tissues. Regulation of H2S production from CSE is controlled by a complex integration of transcriptional, posttranscriptional, and posttranslational mechanisms in blood vessels. In smooth muscle cells, H2S regulates cell apoptosis, phenotypic switch, relaxation and contraction, and calcification. In endothelial cells, H2S controls cell proliferation, cellular senescence, oxidative stress, inflammation, etc. H2S interacts with nitric oxide and acts as an endothelium-derived relaxing factor and an endothelium-derived hyperpolarizing factor. H2S generated from periadventitial adipose tissues acts as an adipocyte-derived relaxing factor and modulates the vascular tone. Extensive evidence has demonstrated the beneficial roles of the CSE/H2S system in various blood vessel diseases, such as hypertension, atherosclerosis, and aortic aneurysm. The important roles signaling in the cardiovascular system merit further intensive and extensive investigation. H2S-releasing agents and CSE activators will find their great applications in the prevention and treatment of blood vessel-related disorders. PMID:26162830

  7. Nonlinear analysis of blood flux in human vessels.

    PubMed

    Bräuer, K; Hahn, M

    1999-07-01

    Laser Doppler fluxmetry (LDF) is frequently used in research on microcirculation of blood. Usually LDF time series are analysed by conventional linear methods, mainly Fourier analysis. These methods may not be optimal for the investigation of nonlinear effects of vasomotion, heartbeat or vessels. Nonlinear methods are based on a reconstruction of the system trajectory in an embedding space describing not only the measured time series but the behaviour of the whole system. The fill factor is a tool for displaying the main properties of this attractor in two dimensions and for determining diverse parameters for further analysis. A quantitative characterization of the system is possible by the distribution of correlation dimensions in the embedding space. The singular value decomposition (SVD) can be used to display and characterize individual degrees of freedom. These methods were applied to LDF time series from nine healthy controls and nine patients with Raynaud's phenomenon due to connective tissue disease. The fill factor and the SVD indicate qualitatively that in the controls vasomotion and heartbeat are the main influences on blood flow and act fairly independently of each other. In the patients there was a mixture of strong but irregular degrees of freedom. The mean and the maximal local correlation dimensions were significantly higher in the patient group. Nonlinear analysis of LDF time series provides additional information which cannot be detected using conventional approaches. PMID:10442708

  8. Plug Effect of Erythrocytes in Capillary Blood Vessels

    PubMed Central

    Lew, H. S.; Fung, Y. C.

    1970-01-01

    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

  9. Blood vessel extraction and optic disc removal using curvelet transform and kernel fuzzy c-means.

    PubMed

    Kar, Sudeshna Sil; Maity, Santi P

    2016-03-01

    This paper proposes an automatic blood vessel extraction method on retinal images using matched filtering in an integrated system design platform that involves curvelet transform and kernel based fuzzy c-means. Since curvelet transform represents the lines, the edges and the curvatures very well and in compact form (by less number of coefficients) compared to other multi-resolution techniques, this paper uses curvelet transform for enhancement of the retinal vasculature. Matched filtering is then used to intensify the blood vessels' response which is further employed by kernel based fuzzy c-means algorithm that extracts the vessel silhouette from the background through non-linear mapping. For pathological images, in addition to matched filtering, Laplacian of Gaussian filter is also employed to distinguish the step and the ramp like signal from that of vessel structure. To test the efficacy of the proposed method, the algorithm has also been applied to images in presence of additive white Gaussian noise where the curvelet transform has been used for image denoising. Performance is evaluated on publicly available DRIVE, STARE and DIARETDB1 databases and is compared with the large number of existing blood vessel extraction methodologies. Simulation results demonstrate that the proposed method is very much efficient in detecting the long and the thick as well as the short and the thin vessels with an average accuracy of 96.16% for the DRIVE and 97.35% for the STARE database wherein the existing methods fail to extract the tiny and the thin vessels. PMID:26848729

  10. HIFU procedures at moderate intensities--effect of large blood vessels.

    PubMed

    Hariharan, P; Myers, M R; Banerjee, R K

    2007-06-21

    A three-dimensional computational model is presented for studying the efficacy of high-intensity focused ultrasound (HIFU) procedures targeted near large blood vessels. The analysis applies to procedures performed at intensities below the threshold for cavitation, boiling and highly nonlinear propagation, but high enough to increase tissue temperature a few degrees per second. The model is based upon the linearized KZK equation and the bioheat equation in tissue. In the blood vessel the momentum and energy equations are satisfied. The model is first validated in a tissue phantom, to verify the absence of bubble formation and nonlinear effects. Temperature rise and lesion-volume calculations are then shown for different beam locations and orientations relative to a large vessel. Both single and multiple ablations are considered. Results show that when the vessel is located within about a beam width (few mm) of the ultrasound beam, significant reduction in lesion volume is observed due to blood flow. However, for gaps larger than a beam width, blood flow has no major effect on the lesion formation. Under the clinically representative conditions considered, the lesion volume is reduced about 40% (relative to the no-flow case) when the beam is parallel to the blood vessel, compared to about 20% for a perpendicular orientation. Procedures involving multiple ablation sites are affected less by blood flow than single ablations. The model also suggests that optimally focused transducers can generate lesions that are significantly larger (>2 times) than the ones produced by highly focused beams. PMID:17664556

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

    NASA Astrophysics Data System (ADS)

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

    1999-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  13. DLC coating of textile blood vessels using PLD

    NASA Astrophysics Data System (ADS)

    Kocourek, Tomas; Jelinek, Miroslav; Vorlíček, Vladimír; Zemek, Josef; Janča, Tomáš; Žížková, Věra; Podlaha, Jiří; Popov, Cyril

    2008-11-01

    Textile blood vessels with a length of 30 cm were coated with amorphous diamond-like carbon (DLC) layers with thicknesses up to 200 nm. The layers were created by pulsed laser deposition in vacuum or argon ambient. The percentage of sp3 carbon was evaluated using X-ray photoelectron spectroscopy, X-ray excited Auger electron spectroscopy and Raman spectroscopy. Depending on the deposition conditions the sp3 content varied from ˜40% to 60%. The adhesion of the DLC layers to the textile vessels was checked. The preliminary biocompatibility results from in vivo tests with sheep are also given.

  14. Twisted Blood Vessels: Symptoms, Etiology and Biomechanical Mechanisms

    PubMed Central

    Han, Hai-Chao

    2012-01-01

    Tortuous arteries and veins are commonly observed in humans and animals. While mild tortuosity is asymptomatic, severe tortuosity can lead to ischemic attack in distal organs. Clinical observations have linked tortuous arteries and veins with aging, atherosclerosis, hypertension, genetic defects and diabetes mellitus. However, the mechanisms of their formation and development are poorly understood. This review summarizes the current clinical and biomechanical studies on the initiation, development and treatment of tortuous blood vessels. We submit a new hypothesis that mechanical instability and remodeling could be mechanisms for the initiation and development of these tortuous vessels. PMID:22433458

  15. Dimensional analysis of blood vessel images in real time

    NASA Astrophysics Data System (ADS)

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

    1996-01-01

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

  16. Melanopsin mediates light-dependent relaxation in blood vessels

    PubMed Central

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

    2014-01-01

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

  17. Control of Blood Vessel Identity: From Embryo to Adult

    PubMed Central

    2008-01-01

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

  18. Mathematical modelling for trajectories of magnetic nanoparticles in a blood vessel under magnetic field

    NASA Astrophysics Data System (ADS)

    Sharma, Shashi; Katiyar, V. K.; Singh, Uaday

    2015-04-01

    A mathematical model is developed to describe the trajectories of a cluster of magnetic nanoparticles in a blood vessel for the application of magnetic drug targeting (MDT). The magnetic nanoparticles are injected into a blood vessel upstream from a malignant tissue and are captured at the tumour site with help of an applied magnetic field. The applied field is produced by a rare earth cylindrical magnet positioned outside the body. All forces expected to significantly affect the transport of nanoparticles were incorporated, including magnetization force, drag force and buoyancy force. The results show that particles are slow down and captured under the influence of magnetic force, which is responsible to attract the magnetic particles towards the magnet. It is optimized that all particles are captured either before or at the centre of the magnet (z≤0) when blood vessel is very close proximity to the magnet (d=2.5 cm). However, as the distance between blood vessel and magnet (d) increases (above 4.5 cm), the magnetic nanoparticles particles become free and they flow away down the blood vessel. Further, the present model results are validated by the simulations performed using the finite element based COMSOL software.

  19. Scatter factor induces blood vessel formation in vivo.

    PubMed Central

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

    1993-01-01

    Scatter factor (also known as hepatocyte growth factor) is a glycoprotein secreted by stromal cells that stimulates cell motility and proliferation. In vitro, scatter factor stimulates vascular endothelial cell migration, proliferation, and organization into capillary-like tubes. Using two different in vivo assays, we showed that physiologic quantities of purified native mouse scatter factor and recombinant human hepatocyte growth factor induce angiogenesis (the formation of new blood vessels). The angiogenic activity was blocked by specific anti-scatter factor antibodies. Scatter factor induced cultured microvascular endothelial cells to accumulate and secrete significantly increased quantities of urokinase, an enzyme associated with development of an invasive endothelial phenotype during angiogenesis. We further showed that immunoreactive scatter factor is present surrounding sites of blood vessel formation in psoriatic skin. These findings suggest that scatter factor may act as a paracrine mediator in pathologic angiogenesis associated with human inflammatory disease. Images Fig. 1 Fig. 2 Fig. 3 Fig. 5 PMID:7680481

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

    PubMed

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

    2015-01-01

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

  1. Numerical study of the effect of blood vessel on the microwave ablation shape.

    PubMed

    Nie, Xiaohui; Nan, Qun; Guo, Xuemei; Tian, Zhen

    2015-01-01

    The existence of large blood vessels seriously impacts the results of microwave ablation on heat transfer of surrounding tissue, and the research of influences about large blood vessels could be essential and significant. The temperature distribution in the tissue was analyzed with a microwave heating source by finite element method. The model, where the blood vessel is parallel to antenna, has different distances from antenna to blood vessel. As distance was greater than 20mm, the effect of blood vessel that was parallel to antenna was ignored and the ablation area was elliptical-like. When distance was less than 10mm, the part of asymmetrical coagulated area was on the right side of blood vessel. Therefore, the temperature contour by different conditions could provide numerical references, which is whether to block blood vessel or not, to achieve the aim of guiding the clinical practice, according to the locations of tumor and blood vessel. PMID:26406011

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  3. Understanding and exploiting nanoparticles' intimacy with the blood vessel and blood.

    PubMed

    Setyawati, Magdiel Inggrid; Tay, Chor Yong; Docter, Dominic; Stauber, Roland H; Leong, David Tai

    2015-11-21

    While the blood vessel is seldom the target tissue, almost all nanomedicine will interact with blood vessels and blood at some point of time along its life cycle in the human body regardless of their intended destination. Despite its importance, many bionanotechnologists do not feature endothelial cells (ECs), the blood vessel cells, or consider blood effects in their studies. Including blood vessel cells in the study can greatly increase our understanding of the behavior of any given nanomedicine at the tissue of interest or to understand side effects that may occur in vivo. In this review, we will first describe the diversity of EC types found in the human body and their unique behaviors and possibly how these important differences can implicate nanomedicine behavior. Subsequently, we will discuss about the protein corona derived from blood with foci on the physiochemical aspects of nanoparticles (NPs) that dictate the protein corona characteristics. We would also discuss about how NPs characteristics can affect uptake by the endothelium. Subsequently, mechanisms of how NPs could cross the endothelium to access the tissue of interest. Throughout the paper, we will share some novel nanomedicine related ideas and insights that were derived from the understanding of the NPs' interaction with the ECs. This review will inspire more exciting nanotechnologies that had accounted for the complexities of the real human body. PMID:26239875

  4. Mathematical modeling and simulation of the evolution of plaques in blood vessels.

    PubMed

    Yang, Yifan; Jäger, Willi; Neuss-Radu, Maria; Richter, Thomas

    2016-03-01

    In this paper, a model is developed for the evolution of plaques in arteries, which is one of the main causes for the blockage of blood flow. Plaque rupture and spread of torn-off material may cause closures in the down-stream vessel system and lead to ischemic brain or myocardial infarctions. The model covers the flow of blood and its interaction with the vessel wall. It is based on the assumption that the penetration of monocytes from the blood flow into the vessel wall, and the accumulation of foam cells increasing the volume, are main factors for the growth of plaques. The dynamics of the vessel wall is governed by a deformation gradient, which is given as composition of a purely elastic tensor, and a tensor modeling the biologically caused volume growth. An equation for the evolution of the metric is derived quantifying the changing geometry of the vessel wall. To calculate numerically the solutions of the arising free boundary problem, the model system of partial differential equations is transformed to an ALE (Arbitrary Lagrangian-Eulerian) formulation, where all equations are given in fixed domains. The numerical calculations are using newly developed algorithms for ALE systems. The results of the simulations, obtained for realistic system parameters, are in good qualitative agreement with observations. They demonstrate that the basic modeling assumption can be justified. The increase of stresses in the vessel wall can be computed. Medical treatment tries to prevent critical stress values, which may cause plaque rupture and its consequences. PMID:26385578

  5. New algorithm for detecting smaller retinal blood vessels in fundus images

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    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.

  6. Modeling blood flow in vessels with changeable caliber for physiology and biophysics courses.

    PubMed

    Kozlova, E K; Badicov, V I; Chemysh, A M; Bogushevich, M S

    1997-06-01

    A model based on elementary principles of hydrodynamics and mathematics is proposed for classroom research on concepts related to blood flow physiology. This is an analog model of the vascular system in which blood flow is represented by electrical current flowing in a resistance circuit. The model permits analysis of the change in hemodynamics with local stenosis of both large and peripheral vessels. PMID:9227648

  7. A computational model predicting disruption of blood vessel development.

    PubMed

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

    2013-04-01

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

  8. Microprobes For Blood Flow Measurements In Tissue And Small Vessels

    NASA Astrophysics Data System (ADS)

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

    1988-04-01

    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.

  9. The onchocercal nodule: interrelationship of adult worms and blood vessels.

    PubMed

    George, G H; Palmieri, J R; Connor, D H

    1985-11-01

    This study of onchocercal nodules reveals an intimate relationship between the cuticle of Onchocerca volvulus and the capillaries of the host. Perfusion of blood vessels with India ink and other special techniques reveal a proliferation of capillaries around the worms and communication between small vessels and the spaces around the worms. The space around the worm is continuous with the central fibrin lake. These findings, together with the fact that the worm's gut contains hemosiderin, suggest that the worm subverts the vascular reaction and causes within the nodule a controlled hemorrhage that serves the worm's nutritional needs. We believe this explains, in part, how worms survive in fibrous nodules for many years. PMID:3834800

  10. Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights

    NASA Technical Reports Server (NTRS)

    Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

    2004-01-01

    One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

  11. Automatic Tuning of Spatially Varying Transfer Functions for Blood Vessel Visualization.

    PubMed

    Lathen, G; Lindholm, S; Lenz, R; Persson, A; Borga, M

    2012-12-01

    Computed Tomography Angiography (CTA) is commonly used in clinical routine for diagnosing vascular diseases. The procedure involves the injection of a contrast agent into the blood stream to increase the contrast between the blood vessels and the surrounding tissue in the image data. CTA is often visualized with Direct Volume Rendering (DVR) where the enhanced image contrast is important for the construction of Transfer Functions (TFs). For increased efficiency, clinical routine heavily relies on preset TFs to simplify the creation of such visualizations for a physician. In practice, however, TF presets often do not yield optimal images due to variations in mixture concentration of contrast agent in the blood stream. In this paper we propose an automatic, optimization-based method that shifts TF presets to account for general deviations and local variations of the intensity of contrast enhanced blood vessels. Some of the advantages of this method are the following. It computationally automates large parts of a process that is currently performed manually. It performs the TF shift locally and can thus optimize larger portions of the image than is possible with manual interaction. The method is based on a well known vesselness descriptor in the definition of the optimization criterion. The performance of the method is illustrated by clinically relevant CT angiography datasets displaying both improved structural overviews of vessel trees and improved adaption to local variations of contrast concentration. PMID:26357142

  12. 3D-reconstruction of blood vessels by ultramicroscopy

    PubMed Central

    Jährling, Nina; Becker, Klaus

    2009-01-01

    As recently shown, ultramicroscopy (UM) allows 3D-visualization of even large microscopic structures with µm resolution. Thus, it can be applied to anatomical studies of numerous biological and medical specimens. We reconstructed the three-dimensional architecture of tomato-lectin (Lycopersicon esculentum) stained vascular networks by UM in whole mouse organs. The topology of filigree branches of the microvasculature was visualized. Since tumors require an extensive growth of blood vessels to survive, this novel approach may open up new vistas in neurobiology and histology, particularly in cancer research. PMID:20539742

  13. The role of blood vessels in high-resolution volume conductor head modeling of EEG.

    PubMed

    Fiederer, L D J; Vorwerk, J; Lucka, F; Dannhauer, M; Yang, S; Dümpelmann, M; Schulze-Bonhage, A; Aertsen, A; Speck, O; Wolters, C H; Ball, T

    2016-03-01

    Reconstruction of the electrical sources of human EEG activity at high spatio-temporal accuracy is an important aim in neuroscience and neurological diagnostics. Over the last decades, numerous studies have demonstrated that realistic modeling of head anatomy improves the accuracy of source reconstruction of EEG signals. For example, including a cerebro-spinal fluid compartment and the anisotropy of white matter electrical conductivity were both shown to significantly reduce modeling errors. Here, we for the first time quantify the role of detailed reconstructions of the cerebral blood vessels in volume conductor head modeling for EEG. To study the role of the highly arborized cerebral blood vessels, we created a submillimeter head model based on ultra-high-field-strength (7T) structural MRI datasets. Blood vessels (arteries and emissary/intraosseous veins) were segmented using Frangi multi-scale vesselness filtering. The final head model consisted of a geometry-adapted cubic mesh with over 17×10(6) nodes. We solved the forward model using a finite-element-method (FEM) transfer matrix approach, which allowed reducing computation times substantially and quantified the importance of the blood vessel compartment by computing forward and inverse errors resulting from ignoring the blood vessels. Our results show that ignoring emissary veins piercing the skull leads to focal localization errors of approx. 5 to 15mm. Large errors (>2cm) were observed due to the carotid arteries and the dense arterial vasculature in areas such as in the insula or in the medial temporal lobe. Thus, in such predisposed areas, errors caused by neglecting blood vessels can reach similar magnitudes as those previously reported for neglecting white matter anisotropy, the CSF or the dura - structures which are generally considered important components of realistic EEG head models. Our findings thus imply that including a realistic blood vessel compartment in EEG head models will be helpful to

  14. Meningial blood vessel calcification in the brain of the cat.

    PubMed

    Mandara, Maria Teresa

    2003-03-01

    Mineralization in the wall of central nervous system blood vessels is sporadically encountered in aged horses and cattle as in man, generally as an age-related change. This phenomenon has not to date been located in the meninges in dogs or cats. The present study reports a retrospective histological examination of 50 feline brains from 40-day- to 13-year-old cats. Histological examination using routine staining techniques (hematoxylin and eosin, Luxol fast blue-periodic acid-Schiff) and special stains (Von Kossa and Pearl's method) showed substantial blood vessel calcification (BVC) in 29 cases which, except for 1 case, was present only in the leptomeninges. In 72% of cases BVC was not related to nervous tissue lesions. For this reason it was considered an incidental finding, producing no morphological or clinical signs. However, BVC should not be considered merely an age-related finding since it is also quite common in very young animals (35%), suggesting that its pathogenesis needs to be investigated further and compared to BVC observed in children affected by acquired immune deficiency and idiopathic arterial calcification. PMID:12557010

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  16. A study of the sink effect by blood vessels in radiofrequency ablation.

    PubMed

    Zorbas, George; Samaras, Theodoros

    2015-02-01

    The objective of the current work was to study the sink effect in radiofrequency ablation (RFA) caused by a blood vessel located close to an electrode in a two-compartment numerical model, consisting of a spherical tumor embedded in healthy liver tissue. Several blood vessels of different sizes were studied at different distances from the electrode. It was found that when a straight blood vessel, cylindrical in shape, is located parallel to the electrode, the minimum distance for a drop of only 10% in the isothermal treatment volume above 50°C, compared to the model without the blood vessel, varies from 4.49 mm (for a vessel of 2mm in diameter) to 20.02 mm (for a vessel 20mm in diameter). The results can be used as a guideline to clinical practitioners, in order to quickly assess the potential impact of existing blood vessels on the resulting treatment volume. PMID:25575184

  17. A Heuristic Framework for Image Filtering and Segmentation: Application to Blood Vessel Immunohistochemistry.

    PubMed

    Tsou, Chi-Hsuan; Lu, Yi-Chien; Yuan, Ang; Chang, Yeun-Chung; Chen, Chung-Ming

    2015-01-01

    The blood vessel density in a cancerous tissue sample may represent increased levels of tumor growth. However, identifying blood vessels in the histological (tissue) image is difficult and time-consuming and depends heavily on the observer's experience. To overcome this drawback, computer-aided image analysis frameworks have been investigated in order to boost object identification in histological images. We present a novel algorithm to automatically abstract the salient regions in blood vessel images. Experimental results show that the proposed framework is capable of deriving vessel boundaries that are comparable to those demarcated manually, even for vessel regions with weak contrast between the object boundaries and background clutter. PMID:26819914

  18. A Heuristic Framework for Image Filtering and Segmentation: Application to Blood Vessel Immunohistochemistry

    PubMed Central

    Tsou, Chi-Hsuan; Lu, Yi-Chien; Yuan, Ang; Chang, Yeun-Chung; Chen, Chung-Ming

    2015-01-01

    The blood vessel density in a cancerous tissue sample may represent increased levels of tumor growth. However, identifying blood vessels in the histological (tissue) image is difficult and time-consuming and depends heavily on the observer's experience. To overcome this drawback, computer-aided image analysis frameworks have been investigated in order to boost object identification in histological images. We present a novel algorithm to automatically abstract the salient regions in blood vessel images. Experimental results show that the proposed framework is capable of deriving vessel boundaries that are comparable to those demarcated manually, even for vessel regions with weak contrast between the object boundaries and background clutter. PMID:26819914

  19. Development of blood vessel searching system using near-infrared light stereo method for clinical blood sampling

    NASA Astrophysics Data System (ADS)

    Cheng, Kai; Morita, Yusuke; Nakamachi, Eiji; Honda, Norihiro; Awazu, Kunio

    2014-10-01

    We developed an accurate three-dimensional blood vessel search (3D BVS) system using NIR light for the clinical blood sampling. In the previous study, the 3D BVS system, which used near-infrared (NIR) light imaging and the stereo method to locate blood vessel accurately in three dimensions has been developed(1). However, as NIR lights could not transmit the human arm, this system could not be used for the subcutaneous blood vessel detection. In this study, we developed a BVS by using the reflecting NIR light for blood sampling assist. The light scattering in human tissue will cause blur of blood vessel edge in image, that makes the diameter of blood vessel became uncertain. In this study, a light propagation simulation and a multilayer phantom were adopted to estimate the measurement error of blood vessel diameter in our BSV system. In the simulation, the optical properties of scattering coefficient, absorption coefficient, and refractive index were set similar with human skin. Next, we fabricated a multilayer phantom, which has the similar structure and optical properties with the human skin to confirm availability of the simulation. Also, the optical properties of our phantom are adjustable in our phantom to imitate the different color of skin. We established the estimation algorithm to detect the blood vessel accurately. Finally, we confirm the availability of our BVS for the blood sampling assist system.

  20. Blood vessels and lymphatics in calcific aortic stenosis--in support of its inflammatory pathogenesis.

    PubMed

    Steiner, I; Krbal, L; Dominik, J

    2010-04-01

    In developed countries, calcific aortic stenosis (CAS) has become the most common acquired valvular disease. It is considered a for of atherosclerosis and, like the latter, of inflammatory origin. Majority of cases of CAS are classified etiologically as either senile ("degenerative")--developing on previously normal aortic valve with three cusps, or based on congenitally malformed--bicuspid aortic valve. Twenty-eight cases of CAS (18 of the senile type, 7 of the bicuspid valve type, and 3 of indeterminable type) were examined by means of histology and immunohistochemistry (CD31 for blood vessels; D2-40 for lymphatics). In the calcified cusps, blood vessels were present in all 28 cases, and lymphatics in 14 of them. Vascularization was associated with lymphocytic infiltrates in 24 cases. There was no difference in the pattern between the two types of CAS. The origin of the cusp vessels is discussed. Our finding in the calcified cusps of both blood and lymphatic vessels together with lymphocytic infiltrates supports the inflammatory theory of the CAS pathogenesis. PMID:21275223

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

    PubMed Central

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

    2009-01-01

    We have numerically investigated the axisymmetric motion of a finite-sized nearly occluding air bubble through a shear-thinning Casson fluid flowing in blood vessels of circular cross section. The numerical solution entails solving a two-layer fluid model—a cell-free layer and a non-Newtonian core together with the gas bubble. This problem is of interest to the field of rheology and for gas embolism studies in health sciences. The numerical method is based on a modified front-tracking method. The viscosity expression in the Casson model for blood (bulk fluid) includes the hematocrit [the volume fraction of red blood cells (RBCs)] as an explicit parameter. Three different flow Reynolds numbers, Reapp=ρlUmaxd/μapp, in the neighborhood of 0.2, 2, and 200 are investigated. Here, ρl is the density of blood, Umax is the centerline velocity of the inlet Casson profile, d is the diameter of the vessel, and μapp 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), λ, in the range 0.9≤λ≤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

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    We have numerically investigated the axisymmetric motion of a finite-sized nearly occluding air bubble through a shear-thinning Casson fluid flowing in blood vessels of circular cross section. The numerical solution entails solving a two-layer fluid model—a cell-free layer and a non-Newtonian core together with the gas bubble. This problem is of interest to the field of rheology and for gas embolism studies in health sciences. The numerical method is based on a modified front-tracking method. The viscosity expression in the Casson model for blood (bulk fluid) includes the hematocrit [the volume fraction of red blood cells (RBCs)] as an explicit parameter. Three different flow Reynolds numbers, Reapp=ρlUmaxd/μapp , in the neighborhood of 0.2, 2, and 200 are investigated. Here, ρl is the density of blood, Umax is the centerline velocity of the inlet Casson profile, d is the diameter of the vessel, and μapp 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), λ , in the range 0.9⩽λ⩽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

  3. Pattern of blood vessels in eyes with coloboma

    PubMed Central

    Lingam, Gopal

    2013-01-01

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

  4. Heterogeneity of muscarinic receptor subtypes in cerebral blood vessels

    SciTech Connect

    Garcia-Villalon, A.L.; Krause, D.N.; Ehlert, F.J.; Duckles, S.P. )

    1991-07-01

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

  5. Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography

    PubMed Central

    Bhaduri, Basanta; Nolan, Ryan M.; Shelton, Ryan L.; Pilutti, Lara A.; Motl, Robert W.; Moss, Heather E.; Pula, John H.; Boppart, Stephen A.

    2016-01-01

    Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a history of optic neuritis (ON), and control subjects from the cross-sectional retinal images from OCT. Blood vessel diameter (BVD), blood vessel number (BVN), and retinal nerve fiber layer thickness (RNFLT) were extracted from OCT images collected from around the optic nerves of 129 eyes (24 control, 24 MS + ON, 81 MS-ON) of 71 subjects. Associations between blood vessel metrics, MS diagnosis, MS disability, ON, and RNFLT were evaluated using generalized estimating equation (GEE) models. MS eyes had a lower total BVD and BVN than control eyes. The effect was more pronounced with increased MS disability, and persisted in multivariate models adjusting for RNFLT and ON history. Twenty-nine percent (29%) of MS subjects had fewer retinal blood vessels than all control subjects. MS diagnosis, disability, and ON history were not associated with average blood vessel size. The relationship between MS and lower total BVD/BVN is not accounted for by RNFLT or ON. Further study is needed to determine the relationship between OCT blood vessel metrics and qualitative retinal blood vessel abnormalities in MS. PMID:27375947

  6. Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography.

    PubMed

    Bhaduri, Basanta; Nolan, Ryan M; Shelton, Ryan L; Pilutti, Lara A; Motl, Robert W; Moss, Heather E; Pula, John H; Boppart, Stephen A

    2016-06-01

    Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a history of optic neuritis (ON), and control subjects from the cross-sectional retinal images from OCT. Blood vessel diameter (BVD), blood vessel number (BVN), and retinal nerve fiber layer thickness (RNFLT) were extracted from OCT images collected from around the optic nerves of 129 eyes (24 control, 24 MS + ON, 81 MS-ON) of 71 subjects. Associations between blood vessel metrics, MS diagnosis, MS disability, ON, and RNFLT were evaluated using generalized estimating equation (GEE) models. MS eyes had a lower total BVD and BVN than control eyes. The effect was more pronounced with increased MS disability, and persisted in multivariate models adjusting for RNFLT and ON history. Twenty-nine percent (29%) of MS subjects had fewer retinal blood vessels than all control subjects. MS diagnosis, disability, and ON history were not associated with average blood vessel size. The relationship between MS and lower total BVD/BVN is not accounted for by RNFLT or ON. Further study is needed to determine the relationship between OCT blood vessel metrics and qualitative retinal blood vessel abnormalities in MS. PMID:27375947

  7. The vascular Ca2+-sensing receptor regulates blood vessel tone and blood pressure.

    PubMed

    Schepelmann, M; Yarova, P L; Lopez-Fernandez, I; Davies, T S; Brennan, S C; Edwards, P J; Aggarwal, A; Graça, J; Rietdorf, K; Matchkov, V; Fenton, R A; Chang, W; Krssak, M; Stewart, A; Broadley, K J; Ward, D T; Price, S A; Edwards, D H; Kemp, P J; Riccardi, D

    2016-02-01

    The extracellular calcium-sensing receptor CaSR is expressed in blood vessels where its role is not completely understood. In this study, we tested the hypothesis that the CaSR expressed in vascular smooth muscle cells (VSMC) is directly involved in regulation of blood pressure and blood vessel tone. Mice with targeted CaSR gene ablation from vascular smooth muscle cells (VSMC) were generated by breeding exon 7 LoxP-CaSR mice with animals in which Cre recombinase is driven by a SM22α promoter (SM22α-Cre). Wire myography performed on Cre-negative [wild-type (WT)] and Cre-positive (SM22α)CaSR(Δflox/Δflox) [knockout (KO)] mice showed an endothelium-independent reduction in aorta and mesenteric artery contractility of KO compared with WT mice in response to KCl and to phenylephrine. Increasing extracellular calcium ion (Ca(2+)) concentrations (1-5 mM) evoked contraction in WT but only relaxation in KO aortas. Accordingly, diastolic and mean arterial blood pressures of KO animals were significantly reduced compared with WT, as measured by both tail cuff and radiotelemetry. This hypotension was mostly pronounced during the animals' active phase and was not rescued by either nitric oxide-synthase inhibition with nitro-l-arginine methyl ester or by a high-salt-supplemented diet. KO animals also exhibited cardiac remodeling, bradycardia, and reduced spontaneous activity in isolated hearts and cardiomyocyte-like cells. Our findings demonstrate a role for CaSR in the cardiovascular system and suggest that physiologically relevant changes in extracellular Ca(2+) concentrations could contribute to setting blood vessel tone levels and heart rate by directly acting on the cardiovascular CaSR. PMID:26538090

  8. Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels

    PubMed Central

    Zhang, Yue

    2016-01-01

    Summary Since nanoparticles are now widely applied as food additives, in cosmetics and other industries, especially in medical therapy and diagnosis, we ask here whether nanoparticles can cause several adverse effects to human health. In this review, based on research on nanotoxicity, we mainly discuss the negative influence of nanoparticles on blood vessels in several aspects and the potential mechanism for nanoparticles to penetrate endothelial layers of blood vessels, which are the sites of phosphorylation of tight junction proteins (claudins, occludins, and ZO (Zonula occludens)) proteins, oxidative stress and shear stress. We propose a connection between the presence of nanoparticles and the regulation of the tight junction, which might be the key approach for nanoparticles to penetrate endothelial layers and then have an impact on other tissues and organs. PMID:27335757

  9. Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels.

    PubMed

    Zhang, Yue; Yang, Wan-Xi

    2016-01-01

    Since nanoparticles are now widely applied as food additives, in cosmetics and other industries, especially in medical therapy and diagnosis, we ask here whether nanoparticles can cause several adverse effects to human health. In this review, based on research on nanotoxicity, we mainly discuss the negative influence of nanoparticles on blood vessels in several aspects and the potential mechanism for nanoparticles to penetrate endothelial layers of blood vessels, which are the sites of phosphorylation of tight junction proteins (claudins, occludins, and ZO (Zonula occludens)) proteins, oxidative stress and shear stress. We propose a connection between the presence of nanoparticles and the regulation of the tight junction, which might be the key approach for nanoparticles to penetrate endothelial layers and then have an impact on other tissues and organs. PMID:27335757

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

    SciTech Connect

    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

    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.

  11. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction - a Finite Element Simulation Study.

    PubMed

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30-40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  12. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction – a Finite Element Simulation Study

    PubMed Central

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30–40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  13. Elastomeric free-form blood vessels for interconnecting organs on chip systems.

    PubMed

    Zhang, Weijia; Zhang, Yu Shrike; Bakht, Syeda Mahwish; Aleman, Julio; Shin, Su Ryon; Yue, Kan; Sica, Marco; Ribas, João; Duchamp, Margaux; Ju, Jie; Sadeghian, Ramin Banan; Kim, Duckjin; Dokmeci, Mehmet Remzi; Atala, Anthony; Khademhosseini, Ali

    2016-04-26

    Conventional blood vessel-on-a-chip models are typically based on microchannel-like structures enclosed within bulk elastomers such as polydimethylsiloxane (PDMS). However, these bulk vascular models largely function as individual platforms and exhibit limited flexibility particularly when used in conjunction with other organ modules. Oftentimes, lengthy connectors and/or tubes are still needed to interface multiple chips, resulting in a large waste volume counterintuitive to the miniaturized nature of organs-on-chips. In this work, we report the development of a novel form of a vascular module based on PDMS hollow tubes, which closely emulates the morphology and properties of human blood vessels to integrate multiple organs-on-chips. Specifically, we present two templating strategies to fabricate hollow PDMS tubes with adjustable diameters and wall thicknesses, where metal rods or airflow were employed as the inner templates, while plastic tubes were used as the outer template. The PDMS tubes could then be functionalized by human umbilical vein endothelial cells (HUVECs) in their interior surfaces to further construct elastomeric biomimetic blood vessels. The endothelium developed biofunctionality as demonstrated by the expression of an endothelial biomarker (CD31) as well as dose-dependent responses in the secretion of von Willebrand factor and nitric oxide upon treatment with pharmaceutical compounds. We believe that with their clear advantages including high optical transparency, gas permeability, and tunable elasticity matching those of native blood vessels, these free-form PDMS vascular modules can supplement bulk vascular organoids and likely replace inert plastic tubes in integrating multiple organoids into a single microfluidic circuitry. PMID:26999423

  14. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  15. Vasodilator effects of flunarizine on retinal blood vessels in anesthetized rats.

    PubMed

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

    2009-12-01

    The aim of this study was to investigate the effects of intravenous administration of flunarizine on the diameter of retinal blood vessels and blood pressure in anesthetized rats and to compare the effects of this antagonist with those of nicardipine and nifedipine. Retinal vascular images were captured with a fundus camera system for small animals and the diameter of retinal blood vessels contained in the images was measured using image-processing softwares on a personal computer. Blood pressure was continuously measured. Flunarizine [1-30 microg/kg, intravenously (i.v.)] dose-dependently increased the diameter of retinal blood vessels without significantly changing systemic blood pressure. Nicardipine (1-30 microg/kg, i.v.) increased the retinal blood vessel diameter but decreased blood pressure in a dose-dependent manner. Nifedipine (10-100 microg/kg, i.v.) failed to dilate the retinal blood vessels, although it produced comparable depressor responses as those to nicardipine. These results suggest that flunarizine selectively acts on the retinal blood vessels rather than on the peripheral resistance vessels. Flunarizine could therefore be considered as a candidate for therapeutic drugs to treat diseases associated with disorders of retinal circulation without severe cardiovascular side-effects. PMID:19952431

  16. Blood vessel crosstalk during organogenesis-focus on pancreas and endothelial cells.

    PubMed

    Azizoglu, D Berfin; Cleaver, Ondine

    2016-09-01

    Blood vessels form a highly branched, interconnected, and largely stereotyped network of tubes that sustains every organ and tissue in vertebrates. How vessels come to take on their particular architecture, or how they are 'patterned,' and in turn, how they influence surrounding tissues are fundamental questions of organogenesis. Decades of work have begun to elucidate how endothelial progenitors arise and home to precise locations within tissues, integrating attractive and repulsive cues to build vessels where they are needed. Conversely, more recent findings have revealed an exciting facet of blood vessel interaction with tissues, where vascular cells provide signals to developing organs and progenitors therein. Here, we discuss the exchange of reciprocal signals between endothelial cells and neighboring tissues during embryogenesis, with a special focus on the developing pancreas. Understanding the mechanisms driving both sides of these interactions will be crucial to the development of therapies, from improving organ regeneration to efficient production of cell based therapies. Specifically, elucidating the interface of the vasculature with pancreatic lineages, including endocrine cells, will instruct approaches such as generation of replacement beta cells for Type I diabetes. WIREs Dev Biol 2016, 5:598-617. doi: 10.1002/wdev.240 For further resources related to this article, please visit the WIREs website. PMID:27328421

  17. Imaging tissue engineered blood vessel mimics with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bonnema, Garret Thomas

    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

  18. Millimeter-wave absorption by cutaneous blood vessels: a computational study.

    PubMed

    Alekseev, Stanislav I; Ziskin, Marvin C

    2009-10-01

    The aims of the present study were to calculate the specific absorption rate (SAR) and E-field distributions inside cutaneous blood vessels and in surrounding tissues (dermis and fat) depending on the frequency of millimeter wave exposure. Most calculations were performed using the finite-difference time-domain (FDTD) technique. A rectangular block of homogeneous or multilayer tissue with blood vessels located in the center of the block was used as the basic geometry. We found that the SAR reached its maximal value in a long blood vessel oriented parallel to the E-field. It exceeded the SAR in the surrounding dermis by 40%-42% at 42.25 GHz. However, in the same blood vessel oriented perpendicularly to the E-field, the SAR was lower than that of the surrounding dermis. Absorption of millimeter waves in a cutaneous blood vessel was higher at 61.22 GHz than at 42.25 GHz. The SAR distribution in a blood vessel was nearly uniform. Because of the small sizes of cutaneous blood vessels relative to the wavelength, the SAR distributions in these blood vessels can be calculated by using quasi-static theory. PMID:19527954

  19. Ergot Alkaloid-Induced Blood Vessel Dysfunction Contributes to Fescue Toxicosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many effects of fescue toxicosis in grazing animals may be explained by compromised blood vessel function which is linked to the presence of ergot alkaloids in endophyte-infected tall fescue. The body’s network of blood vessels provides for the removal of metabolic waste products and delivery of the...

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

    PubMed Central

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

    2011-01-01

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

  1. Expansion of bubbles under a pulsatile flow regime in decompressed ovine blood vessels.

    PubMed

    Arieli, Ran; Marmur, Abraham

    2016-02-01

    After decompression of ovine large blood vessels, bubbles nucleate and expand at active hydrophobic spots on their luminal aspect. These bubbles will be in the path of the blood flow within the vessel, which might replenish the supply of gas-supersaturated plasma in their vicinity and thus, in contrast with our previous estimations, enhance their growth. We used the data from our previous study on the effect of pulsatile flow in ovine blood vessels stretched on microscope slides and photographed after decompression from hyperbaric exposure. We measured the diameter of 46 bubbles in 4 samples taken from 3 blood vessels (pulmonary artery, pulmonary vein, and aorta) in which both a "multi-bubble active spot" (MBAS)--which produces several bubbles at a time, and at least one "single-bubble active spot" (SBAS)--which produces a single bubble at a time, were seen together. The linear expansion rate for diameter in SBAS ranged from 0.077 to 0.498 mm/min and in MBAS from 0.001 to 0.332 mm/min. There was a trend toward a reduced expansion rate for bubbles in MBAS compared with SBAS. The expansion rate for bubbles in an MBAS when it was surrounded by others was very low. Bubble growth is related to gas tension, and under a flow regime, bubbles expand from a diameter of 0.1 to 1mm in 2-24 min at a gas supersaturation of 620 kPa and lower. There are two phases of bubble development. The slow and disperse initiation of active spots (from nanobubbles to gas micronuclei) continues for more than 1h, whereas the fast increase in size (2-24 min) is governed by diffusion. Bubble-based decompression models should not artificially reduce diffusion constants, but rather take both phases of bubble development into consideration. PMID:26592146

  2. Sensitivity analysis aimed at blood vessels detection using interstitial optical tomography during brain needle biopsy procedures.

    PubMed

    Pichette, Julien; Goyette, Andréanne; Picot, Fabien; Tremblay, Marie-Andrée; Soulez, Gilles; Wilson, Brian C; Leblond, Frédéric

    2015-11-01

    A brain needle biopsy procedure is performed for suspected brain lesions in order to sample tissue that is subsequently analysed using standard histopathology techniques. A common complication resulting from this procedure is brain hemorrhaging from blood vessels clipped off during tissue extraction. Interstitial optical tomography (iOT) has recently been introduced by our group as a mean to assess the presence of blood vessels in the vicinity of the needle. The clinical need to improve safety requires the detection of blood vessels within 2 mm from the outer surface of the needle, since this distance is representative of the volume of tissue that is aspirated durirng tissue extraction. Here, a sensitivity analysis is presented to establish the intrinsic detection limits of iOT based on simulations and experiments using brain tissue phantoms. It is demonstrated that absorbers can be detected with diameters >300 μm located up to >2 mm from the biopsy needle core for bulk optical properties consistent with brain tissue. PMID:26600990

  3. Sensitivity analysis aimed at blood vessels detection using interstitial optical tomography during brain needle biopsy procedures

    PubMed Central

    Pichette, Julien; Goyette, Andréanne; Picot, Fabien; Tremblay, Marie-Andrée; Soulez, Gilles; Wilson, Brian C.; Leblond, Frédéric

    2015-01-01

    A brain needle biopsy procedure is performed for suspected brain lesions in order to sample tissue that is subsequently analysed using standard histopathology techniques. A common complication resulting from this procedure is brain hemorrhaging from blood vessels clipped off during tissue extraction. Interstitial optical tomography (iOT) has recently been introduced by our group as a mean to assess the presence of blood vessels in the vicinity of the needle. The clinical need to improve safety requires the detection of blood vessels within 2 mm from the outer surface of the needle, since this distance is representative of the volume of tissue that is aspirated durirng tissue extraction. Here, a sensitivity analysis is presented to establish the intrinsic detection limits of iOT based on simulations and experiments using brain tissue phantoms. It is demonstrated that absorbers can be detected with diameters >300 μm located up to >2 mm from the biopsy needle core for bulk optical properties consistent with brain tissue. PMID:26600990

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

    PubMed

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

    2008-06-01

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

  5. Transmitted Ultrasound Pressure Variation in Micro Blood Vessel Phantoms

    PubMed Central

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

    2008-01-01

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

  6. Viral mediated gene transfer to sprouting blood vessels during angiogenesis.

    PubMed

    Alian, Akram; Eldor, Amiram; Falk, Haya; Panet, Amos

    2002-08-01

    Several experimental systems have been applied to investigate the development of new blood vessels. Angiogenesis can be followed ex-vivo by culturing explants of rat aorta 'rings' in biomatrix gels. This angiogenesis system was modified for the study of viral vector mediated gene transfer, using adenovirus, vaccinia- and retroviral vectors. Two modifications were introduced to the model in order to facilitate efficient viral mediated gene transfer, (i) placing the aorta ring on top of a thin layer of collagen such that the angiogenic tissue will be accessible to the viral vector; and (ii) infection of the aorta rings prior to embedding them into the collagen matrix. While adenovirus and vaccinia vectors infected efficiently the aorta rings they induced cell death. Subsequent gene transfer experiments were, therefore, carried with retroviral vectors containing vascular endothelial growth factor (VEGF) and the beta-interferon (IFN) genes. Overexpression of VEGF enhanced significantly microvessel sprouting, while overexpression of IFN-beta induced an antiviral effect. The experimental system described in this study can facilitate the application of other viral vectors to the study of genes that may regulate the complex angiogenic process and thereby open new avenues for vascular gene therapy. PMID:12176137

  7. [Blood vessel and nerve damage in total hip arthroplasty].

    PubMed

    Dietze, S; Perka, C; Baecker, H

    2014-01-01

    Blood vessel and nerve damage are uncommon complications in total hip arthroplasty (THA). With an incidence between 0.1 and 0.2 % in primary THA these complications are rare but can be serious with a high mortality risk. The individual risk is determined by multiple factors depending on the surgeon's skills, the number of previous surgeries and the approach itself. The anatomy of the defect is an essential risk factor. Some procedures, such as the use of screws for cup fixation are associated with a higher risk of vascular and neural damage. The acetabular quadrant system of the hip as described by Wasielewski et al. is a useful tool to visualize the neurovascular anatomy of the hip, to detect the safe zone and subsequently prevent complications. Sciatic nerve palsy after total hip replacement is the most common nerve damage followed by femoral nerve damage. Previous surgery, a posterior approach and excessive leg extension are the most common risk factors for nerve damage. In order to diagnose nerve palsy after orthopedic surgery an electromyogram can be of use to assess the extent and prognosis. This article focuses on vascular and neural complications after total hip arthroplasty and the options for diagnosis, treatment and prevention. PMID:24384891

  8. Development of an accurate 3D blood vessel searching system using NIR light

    NASA Astrophysics Data System (ADS)

    Mizuno, Yoshifumi; Katayama, Tsutao; Nakamachi, Eiji

    2010-02-01

    Health monitoring system (HMS) and drug delivery system (DDS) require accurate puncture by needle for automatic blood sampling. In this study, we develop a miniature and high accurate automatic 3D blood vessel searching system. The size of detecting system is 40x25x10 mm. Our searching system use Near-Infrared (NIR) LEDs, CMOS camera modules and image processing units. We employ the stereo method for searching system to determine 3D blood vessel location. Blood vessel visualization system adopts hemoglobin's absorption characterization of NIR light. NIR LED is set behind the finger and it irradiates Near Infrared light for the finger. CMOS camera modules are set in front of the finger and it captures clear blood vessel images. Two dimensional location of the blood vessel is detected by luminance distribution of the image and its depth is calculated by the stereo method. 3D blood vessel location is automatically detected by our image processing system. To examine the accuracy of our detecting system, we carried out experiments using finger phantoms with blood vessel diameters, 0.5, 0.75, 1.0mm, at the depths, 0.5 ~ 2.0 mm, under the artificial tissue surface. Experimental results of depth obtained by our detecting system showed good agreements with given depths, and the availability of this system is confirmed.

  9. Estimation of vessel diameter and blood flow dynamics from laser speckle images

    PubMed Central

    Postnov, Dmitry D.; Tuchin, Valery V.; Sosnovtseva, Olga

    2016-01-01

    Laser speckle imaging is a rapidly developing method to study changes of blood velocity in the vascular networks. However, to assess blood flow and vascular responses it is crucial to measure vessel diameter in addition to blood velocity dynamics. We suggest an algorithm that allows for dynamical masking of a vessel position and measurements of it’s diameter from laser speckle images. This approach demonstrates high reliability and stability. PMID:27446704

  10. Texton-based segmentation of retinal vessels.

    PubMed

    Adjeroh, Donald A; Kandaswamy, Umasankar; Odom, J Vernon

    2007-05-01

    With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE5370, 648 (2004)]. PMID:17429484

  11. Texton-based segmentation of retinal vessels

    NASA Astrophysics Data System (ADS)

    Adjeroh, Donald A.; Kandaswamy, Umasankar; Odom, J. Vernon

    2007-05-01

    With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE5370, 648 (2004)].

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-11-01

    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

  14. Analyzing isolated blood vessel contraction in multi-well plates.

    PubMed

    Borges, Ricardo; Díaz-Martín, David; Hernández-Jiménez, José G; Rodríguez-Valido, Manuel; Beltrán, Beatriz

    2016-05-01

    Organ baths have been successfully used for over a century to study the contractile or relaxation effects of drugs. Indeed, most of our understanding of vascular pharmacology is based on such in vitro studies. However, multiple parallel organ baths that require mechanical transduction consume relatively large amounts of drugs, gases, and buffers, and they take up a considerable bench space. In addition, such experiments have a high demand in terms of cost and animals, and the tissue preparation is labor intensive and slow. For these reasons, organ baths are no longer in the front line of industrial pharmacological research and they have almost disappeared from most academic laboratories. We have developed a very simple system, which can be implemented virtually in any laboratory, for the automatic analyses of rat aorta ring contraction based on optical methods and using multi-well plates. Rat aorta rings (≈0.5 mm wide) were situated in 96-multi-well plates, and the luminal vessel areas were continuously monitored using a USB camera driven by newly developed algorithms. Liquids were handled using multichannel pipettes, although these procedures can be automated for drug screening. The concentration-response curves obtained were similar to those reported in the literature using traditional force transduction techniques on isolated tissues. This system can also be used with other tissue preparations and for simultaneous fluorescence measurements. The new system described here offers a simple, cheap, and reliable alternative to the classic organ bath system. PMID:26905519

  15. Lysophosphatidic acid does not cause blood/lymphatic vessel plasticity in the rat mesentery culture model.

    PubMed

    Sweat, Richard S; Azimi, Mohammad S; Suarez-Martinez, Ariana D; Katakam, Prasad; Murfee, Walter L

    2016-07-01

    Understanding the mechanisms behind endothelial cell identity is crucial for the goal of manipulating microvascular networks. Lysophosphatidic acid (LPA) and serum stimulation have been suggested to induce a lymphatic identity in blood endothelial cells in vitro. The objective of this study was to determine if LPA or serum induces blood-to-lymphatic vessel phenotypic transition in microvascular networks. The rat mesentery culture model was used to observe the effect of stimulation on blood and lymphatic microvascular networks ex vivo. Vascularized mesenteric tissues were harvested from adult Wistar rats and cultured with LPA or 10% serum for up to 5 days. Tissues were then immunolabeled with PECAM to identify blood vessels and LYVE-1 or Prox1 to identify lymphatic vessels. We show that while LPA caused capillary sprouting and increased vascular length density in adult microvascular networks, LPA did not cause a blood-to-lymphatic phenotypic transition. The results suggest that LPA is not sufficient to cause blood endothelial cells to adopt a lymphatic identity in adult microvascular networks. Similarly, serum stimulation caused robust angiogenesis and increased lymphatic/blood vessel connections, yet did not induce a blood-to-lymphatic phenotypic transition. Our study highlights an understudied area of lymphatic research and warrants future investigation into the mechanisms responsible for the maintenance of blood and lymphatic vessel identity. PMID:27401461

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

    PubMed

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  18. 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 ...

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

    PubMed

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

    2000-01-01

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

  20. [The effects of extreme cold on major blood vessels. An experimental study (author's transl)].

    PubMed

    Asbach, H W; Bersch, W; Hochberg, K

    1975-05-01

    In 10 beagles cryogenic experiments were performed to study the effects of freezing the iliac artery and vein. The histological tissue reaction after cold exposure in major pelvic vessels was early inflammation and followed by a rapidly progressing reparative process. Long-term microscopic changes were proliferations of the vessel intima and focal splitting on the elastic membrane. No evidence of thrombosis, aneurysm fomation and rupture of the vessel was found. Vascular function as a blood conduit was undisturbed. PMID:1154562

  1. Blood vessel growth blocker may treat 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).

  2. Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition

    PubMed Central

    Hopp, Christine S; Chiou, Kevin; Ragheb, Daniel RT; Salman, Ahmed M; Khan, Shahid M; Liu, Andrea J; Sinnis, Photini

    2015-01-01

    Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host. How sporozoites locate and enter a blood vessel is a critical, but poorly understood process. In this study, we examine sporozoite motility and their interaction with dermal blood vessels, using intravital microscopy in mice. Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit ‘avascular motility’, defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained. We find that curvature of sporozoite tracks engaging with vasculature optimizes contact with dermal capillaries. Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site. DOI: http://dx.doi.org/10.7554/eLife.07789.001 PMID:26271010

  3. Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition.

    PubMed

    Hopp, Christine S; Chiou, Kevin; Ragheb, Daniel R T; Salman, Ahmed; Khan, Shahid M; Liu, Andrea J; Sinnis, Photini

    2015-01-01

    Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host. How sporozoites locate and enter a blood vessel is a critical, but poorly understood process. In this study, we examine sporozoite motility and their interaction with dermal blood vessels, using intravital microscopy in mice. Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained. We find that curvature of sporozoite tracks engaging with vasculature optimizes contact with dermal capillaries. Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site. PMID:26271010

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

    PubMed

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

    2012-02-01

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

  5. Dynamic Assessment of the Endothelialization of Tissue-Engineered Blood Vessels Using an Optical Coherence Tomography Catheter-Based Fluorescence Imaging System

    PubMed Central

    Gurjarpadhye, Abhijit Achyut; DeWitt, Matthew R.; Xu, Yong; Wang, Ge; Rylander, Marissa Nichole

    2015-01-01

    Background: Lumen endothelialization of bioengineered vascular scaffolds is essential to maintain small-diameter graft patency and prevent thrombosis postimplantation. Unfortunately, nondestructive imaging methods to visualize this dynamic process are lacking, thus slowing development and clinical translation of these potential tissue-engineering approaches. To meet this need, a fluorescence imaging system utilizing a commercial optical coherence tomography (OCT) catheter was designed to visualize graft endothelialization. Methods: C7 DragonFly™ intravascular OCT catheter was used as a channel for delivery and collection of excitation and emission spectra. Poly-dl-lactide (PDLLA) electrospun scaffolds were seeded with endothelial cells (ECs). Seeded cells were exposed to Calcein AM before imaging, causing the living cells to emit green fluorescence in response to blue laser. By positioning the catheter tip precisely over a specimen using high-fidelity electromechanical components, small regions of the specimen were excited selectively. The resulting fluorescence intensities were mapped on a two-dimensional digital grid to generate spatial distribution of fluorophores at single-cell-level resolution. Fluorescence imaging of endothelialization on glass and PDLLA scaffolds was performed using the OCT catheter-based imaging system as well as with a commercial fluorescence microscope. Cell coverage area was calculated for both image sets for quantitative comparison of imaging techniques. Tubular PDLLA scaffolds were maintained in a bioreactor on seeding with ECs, and endothelialization was monitored over 5 days using the OCT catheter-based imaging system. Results: No significant difference was observed in images obtained using our imaging system to those acquired with the fluorescence microscope. Cell area coverage calculated using the images yielded similar values. Nondestructive imaging of endothelialization on tubular scaffolds showed cell proliferation with cell

  6. Aging changes in the heart and blood vessels

    MedlinePlus

    ... control over include high blood pressure, cholesterol levels, diabetes, obesity, and smoking. Eat a heart-healthy diet with ... aorta. Get more exercise: Exercise may help prevent obesity, and ... with diabetes control their blood sugar. Exercise may help you ...

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

    PubMed

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

    2013-01-01

    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

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

    PubMed Central

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

    2013-01-01

    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

  9. Grading vascularity from histopathological images based on traveling salesman distance and vessel size

    NASA Astrophysics Data System (ADS)

    Niazi, M. Khalid Khan; Hemminger, Jessica; Kurt, Habibe; Lozanski, Gerard; Gurcan, Metin

    2014-03-01

    Vascularity represents an important element of tissue/tumor microenvironment and is implicated in tumor growth, metastatic potential and resistence to therapy. Small blood vessels can be visualized using immunohistochemical stains specific to vascular cells. However, currently used manual methods to assess vascular density are poorly reproducible and are at best semi quantitative. Computer based quantitative and objective methods to measure microvessel density are urgently needed to better understand and clinically utilize microvascular density information. We propose a new method to quantify vascularity from images of bone marrow biopsies stained for CD34 vascular lining cells protein as a model. The method starts by automatically segmenting the blood vessels by methods of maxlink thresholding and minimum graph cuts. The segmentation is followed by morphological post-processing to reduce blast and small spurious objects from the bone marrow images. To classify the images into one of the four grades, we extracted 20 features from the segmented blood vessel images. These features include first four moments of the distribution of the area of blood vessels, first four moments of the distribution of 1) the edge weights in the minimum spanning tree of the blood vessels, 2) the shortest distance between blood vessels, 3) the homogeneity of the shortest distance (absolute difference in distance between consecutive blood vessels along the shortest path) between blood vessels and 5) blood vessel orientation. The method was tested on 26 bone marrow biopsy images stained with CD34 IHC stain, which were evaluated by three pathologists. The pathologists took part in this study by quantifying blood vessel density using gestalt assessment in hematopoietic bone marrow portions of bone marrow core biopsies images. To determine the intra-reader variability, each image was graded twice by each pathologist with two-week interval in between their readings. For each image, the ground

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

    NASA Technical Reports Server (NTRS)

    Parsons-Wingerter, Patricia A.

    2003-01-01

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

  11. The extracellular matrix and blood vessel formation: not just a scaffold

    PubMed Central

    Rhodes, John M; Simons, Michael

    2007-01-01

    Abstract The extracellular matrix plays a number of important roles, among them providing structural support and information to cellular structures such as blood vessels imbedded within it. As more complex organisms have evolved, the matrix ability to direct signalling towards the vasculature and remodel in response to signalling from the vasculature has assumed progressively greater importance. This review will focus on the molecules of the extracellular matrix, specifically relating to vessel formation and their ability to signal to the surrounding cells to initiate or terminate processes involved in blood vessel formation. PMID:17488472

  12. Vasodilator Effects of Elcatonin, a Synthetic Eel Calcitonin, on Retinal Blood Vessels in Rats.

    PubMed

    Mori, Asami; Suzawa, Hironori; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2015-01-01

    The aim of this study was to examine the effects of elcatonin, a synthetic derivative of eel calcitonin, on rat retinal blood vessels, and to determine how diabetes affects the retinal vascular responses. Ocular fundus images were captured with an original high-resolution digital fundus camera in vivo. The retinal vascular responses were evaluated by measuring the diameter of retinal blood vessels contained in the digital images. Both systemic blood pressure and heart rate were continuously recorded. Elcatonin increased the diameter of retinal blood vessels but decreased mean blood pressure in a dose-dependent manner, whereas it had no significant effect on heart rate. A diminished retinal vasodilator response and significant pressor response to elcatonin were observed in rats injected intravenously with N(G)-nitro-L-arginine methyl ester, a nitric oxide (NO) synthase inhibitor. Intravitreal injection of indomethacin, a non-selective cyclooxygenase (COX) inhibitor, and SQ22536, an adenylyl cyclase inhibitor, markedly attenuated the vasodilator effects of elcatonin on retinal blood vessels. The retinal vasodilator responses to elcatonin were unaffected 2 weeks after the induction of diabetes by a combination of streptozotocin treatment and D-glucose feeding. These results suggest that elcatonin dilates rat retinal blood vessels via NO- and COX-dependent mechanisms and that the adenylyl cyclase-adenosine 3',5'-cyclic monophosphate system plays a major role in the vasodilator mechanisms. The retinal vasodilatory effects of elcatonin seem to be preserved at early stages of diabetes. PMID:26424018

  13. Vascular bursts enhance permeability of tumour blood vessels and improve nanoparticle delivery

    NASA Astrophysics Data System (ADS)

    Matsumoto, Yu; Nichols, Joseph W.; Toh, Kazuko; Nomoto, Takahiro; Cabral, Horacio; Miura, Yutaka; Christie, R. James; Yamada, Naoki; Ogura, Tadayoshi; Kano, Mitsunobu R.; Matsumura, Yasuhiro; Nishiyama, Nobuhiro; Yamasoba, Tatsuya; Bae, You Han; Kataoka, Kazunori

    2016-06-01

    Enhanced permeability in tumours is thought to result from malformed vascular walls with leaky cell-to-cell junctions. This assertion is backed by studies using electron microscopy and polymer casts that show incomplete pericyte coverage of tumour vessels and the presence of intercellular gaps. However, this gives the impression that tumour permeability is static amid a chaotic tumour environment. Using intravital confocal laser scanning microscopy we show that the permeability of tumour blood vessels includes a dynamic phenomenon characterized by vascular bursts followed by brief vigorous outward flow of fluid (named ‘eruptions’) into the tumour interstitial space. We propose that ‘dynamic vents’ form transient openings and closings at these leaky blood vessels. These stochastic eruptions may explain the enhanced extravasation of nanoparticles from the tumour blood vessels, and offer insights into the underlying distribution patterns of an administered drug.

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed

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

    2013-05-01

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

  16. Vascular bursts enhance permeability of tumour blood vessels and improve nanoparticle delivery.

    PubMed

    Matsumoto, Yu; Nichols, Joseph W; Toh, Kazuko; Nomoto, Takahiro; Cabral, Horacio; Miura, Yutaka; Christie, R James; Yamada, Naoki; Ogura, Tadayoshi; Kano, Mitsunobu R; Matsumura, Yasuhiro; Nishiyama, Nobuhiro; Yamasoba, Tatsuya; Bae, You Han; Kataoka, Kazunori

    2016-06-01

    Enhanced permeability in tumours is thought to result from malformed vascular walls with leaky cell-to-cell junctions. This assertion is backed by studies using electron microscopy and polymer casts that show incomplete pericyte coverage of tumour vessels and the presence of intercellular gaps. However, this gives the impression that tumour permeability is static amid a chaotic tumour environment. Using intravital confocal laser scanning microscopy we show that the permeability of tumour blood vessels includes a dynamic phenomenon characterized by vascular bursts followed by brief vigorous outward flow of fluid (named 'eruptions') into the tumour interstitial space. We propose that 'dynamic vents' form transient openings and closings at these leaky blood vessels. These stochastic eruptions may explain the enhanced extravasation of nanoparticles from the tumour blood vessels, and offer insights into the underlying distribution patterns of an administered drug. PMID:26878143

  17. Relevance of Blood Vessel Networks in Blast-Induced Traumatic Brain Injury.

    PubMed

    Hua, Yi; Lin, Shengmao; Gu, Linxia

    2015-01-01

    Cerebral vasculature is a complex network that circulates blood through the brain. However, the role of this networking effect in brain dynamics has seldom been inspected. This work is to study the effects of blood vessel networks on dynamic responses of the brain under blast loading. Voronoi tessellations were implemented to represent the network of blood vessels in the brain. The brain dynamics in terms of maximum principal strain (MPS), shear strain (SS), and intracranial pressure (ICP) were monitored and compared. Results show that blood vessel networks significantly affected brain responses. The increased MPS and SS were observed within the brain embedded with vessel networks, which did not exist in the case without blood vessel networks. It is interesting to observe that the alternation of the ICP response was minimal. Moreover, the vessel diameter and density also affected brain dynamics in both MPS and SS measures. This work sheds light on the role of cerebral vasculature in blast-induced traumatic brain injury. PMID:26495036

  18. Relevance of Blood Vessel Networks in Blast-Induced Traumatic Brain Injury

    PubMed Central

    Hua, Yi; Lin, Shengmao; Gu, Linxia

    2015-01-01

    Cerebral vasculature is a complex network that circulates blood through the brain. However, the role of this networking effect in brain dynamics has seldom been inspected. This work is to study the effects of blood vessel networks on dynamic responses of the brain under blast loading. Voronoi tessellations were implemented to represent the network of blood vessels in the brain. The brain dynamics in terms of maximum principal strain (MPS), shear strain (SS), and intracranial pressure (ICP) were monitored and compared. Results show that blood vessel networks significantly affected brain responses. The increased MPS and SS were observed within the brain embedded with vessel networks, which did not exist in the case without blood vessel networks. It is interesting to observe that the alternation of the ICP response was minimal. Moreover, the vessel diameter and density also affected brain dynamics in both MPS and SS measures. This work sheds light on the role of cerebral vasculature in blast-induced traumatic brain injury. PMID:26495036

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

    PubMed

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

    2012-04-01

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

  20. Anaphylactic contraction of pulmonary blood vessels of chicken.

    PubMed Central

    Chand, N; Eyre, P

    1977-01-01

    1 Isolated pulmonary arterial and vein strips from sensitized or non-sensitized chickens exhibited dose-dependent contractions to adrenaline greater than, noradrenaline greater than, 5-hydroxytryptamine greater than, histamine greater than, dopamine. Individual variability in the responsiveness of the vessels to agonists was marked. In general veins were 2 to 25 times more sensitive to agonists than arterial strips. 2 Isoprenaline (a relatively specific beta-adrenoceptor agonist) induced relaxation of the submaximally contracted pulmonary vein and arteries at low doses and contractions at high concentrations. 3 Contractile responses to acetylcholine or carbachol were not regularly recorded; only 50% of the vessels reacted to cholinoceptor agonists over a wide threshold dose range. 4 Chicken pulmonary vessels were found relatively insensitive to bradykinin. 5 Effects of prostaglandins were variable. Prostaglandin F2alpha induced dose-related contractions of the vein and arterial strips; prostglandins E1 and E2 at low doses partially contracted pulmonary artery irrespective of the spasmogen used and further increase in doses induced either no effect or contractions. Prostaglandin E1 induced marked and rapid contractions of the vein. Prostaglandin E2 induced relaxations of the prostaglandin F2alpha-contracted vein only, but produced no effect or slight contractions of the veins partially contracted to other spasmogens. 6 Pulmonary arterial and vein strips obtained from chickens sensitized to horse plasma exhibited Schultz-Dale contractions of variable magnitude and duration to specific antigenic challenge only. In many vessels, antigen-induced contractions were associated with marked increase in spontaneous activity. 7 The importance of the Schultz-Dale reaction in avian pulmonary vessels is discussed in relation to the right heart dilatation associated with anaphylaxis in the chicken. PMID:836999

  1. A novel formula for the classification of blood vessels according to symmetry, asymmetry and hypoplasia.

    PubMed

    Zurada, A; Gielecki, J S

    2007-11-01

    A new mathematical formula for calculating the symmetry, asymmetry and hypoplasia of blood vessel segments is presented for discussion. The study was conducted using the computed tomography (CT) files from 80 patients (34 men and 46 women) from the Silesian University Hospital, Silesia, Poland, who were between the ages of 12 to 76 and had undergone CT angiography of the circle of Willis. With the use of Gradual Angiographic Image Data Analyser software and double shuttled glasses, CT files were reconstructed. In addition, 80 renal arteries (RAs) from spontaneously aborted foetuses ranging in age from 14 to 30 weeks (24 male and 16 female) were injected with latex and also included in the study. Digital images of the RAs were taken using a Camedia 4040 camera and analysed using original analysis software. A novel formula entitled the Vascular Asymmetry Coefficient (VAC) was derived for this purpose and displays the differences between the mean diameters of blood vessel segments expressed as a percentage of the wider vessel with respect to the major diameter. The asymmetrical classification for a vascular segment of a vessel is given when the difference between the mean diameters of the vascular segment, as represented by the wider vessel, is greater than VAC > 10%. The hypoplastic classification is reserved for blood vessels where the difference between the diameter of the two segments is expressed as a percentage of the wider vessels and is greater than VAC > 40%. While there have been inconsistent and arbitrary classifications for the qualitative criteria of blood vessels, this newly presented algorithm can be used as a standardised tool and has a considerable range of uses, particularly when comparing blood vessel symmetry, asymmetry and hypoplasia prior to bifurcation, and unification. PMID:18058758

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

    PubMed

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

    2014-08-01

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

  3. Temporo-spatial distribution of blood vessels in human lumbar intervertebral discs

    PubMed Central

    Schaaf, Rainer; Wälchli, Beat; Boos, Norbert

    2006-01-01

    While there is consensus in the literature that blood vessels are confined to the outer anulus fibrosus of normal adult intervertebral disc, debate continues whether there is a vascular in-growths into inner parts of the intervertebral disc during degeneration. We therefore tested the hypothesis that vascular in-growth is not a distinct feature of disc degeneration. The specific endothelial cell marker CD 31 (PECAM) was used to immunohistochemically investigate 42 paraffin-embedded complete mid-sagittal human intervertebral disc sections of various ages (0–86 years) and varying extent of histomorphological degeneration. Additionally, 20 surgical disc samples from individuals (26–69 years) were included in this study. In discs of fetal to infantile age, blood vessels perforated the cartilaginous end plate and extended into the inner and outer anulus fibrosus, but not into the nucleus pulposus. In adolescents and adults, no blood vessels were seen except for the outer zone of the anulus fibrosus adjacent to the insertion to ligaments. The cartilaginous end plate remained free of vessels, except for areas with circumscribed destruction of the end plate. In advanced disc degeneration, no vessels were observed except for those few cases with complete, scar-like disc destruction. However, some rim lesions and occasionally major clefts were surrounded by a small network of capillary blood vessels extending into deeper zones of the anulus fibrosus. A subsequent morphometric analysis, revealed slightly “deeper” blood vessel extension in juvenile/adolescent discs when compared to young, mature and senile adult individuals with significantly “deeper” extension in the posterior than anterior anulus. The analysis of the surgical specimens showed that only sparse capillary blood vessels which did not extend into the nucleus pulposus even in major disc disruption. Our results show that vascular invasion deeper than the periphery was not observed during disc

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

    NASA Astrophysics Data System (ADS)

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

    2007-03-01

    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.

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

    PubMed

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

    2009-11-01

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

  6. Characteristics of Blood Vessels in Female Genital Schistosomiasis: Paving the Way for Objective Diagnostics at the Point of Care

    PubMed Central

    Holmen, Sigve; Galappaththi-Arachchige, Hashini Nilushika; Kleppa, Elisabeth; Pillay, Pavitra; Naicker, Thajasvarie; Taylor, Myra; Onsrud, Mathias; Kjetland, Eyrun Floerecke; Albregtsen, Fritz

    2016-01-01

    Background The mucosal changes associated with female genital schistosomiasis (FGS) encompass abnormal blood vessels. These have been described as circular, reticular, branched, convoluted and having uneven calibre. However, these characteristics are subjective descriptions and it has not been explored which of them are specific to FGS. Methods In colposcopic images of young women from a schistosomiasis endemic area, we performed computerised morphologic analyses of the cervical vasculature appearing on the mucosal surface. Study participants where the cervix was classified as normal served as negative controls, women with clinically diagnosed FGS and presence of typical abnormal blood vessels visible on the cervical surface served as positive cases. We also included women with cervical inflammatory conditions for reasons other than schistosomiasis. By automating morphological analyses, we explored circular configurations, vascular density, fractal dimensions and fractal lacunarity as parameters of interest. Results We found that the blood vessels typical of FGS are characterised by the presence of circular configurations (p < 0.001), increased vascular density (p = 0.015) and increased local connected fractal dimensions (p = 0.071). Using these features, we were able to correctly classify 78% of the FGS-positive cases with an accuracy of 80%. Conclusions The blood vessels typical of FGS have circular configurations, increased vascular density and increased local connected fractal dimensions. These specific morphological features could be used diagnostically. Combined with colourimetric analyses, this represents a step towards making a diagnostic tool for FGS based on computerised image analysis. PMID:27073857

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  8. Aging changes in the heart and blood vessels

    MedlinePlus

    ... lungs to receive oxygen and get rid of carbon dioxide. The left side pumps oxygen-rich blood to ... oxygen and nutrients to the tissues, and receives carbon dioxide and wastes back from the tissues. Then, the ...

  9. Blood vessel adaptation to gravity in a semi-arboreal snake

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  11. Nitric oxide dilates rat retinal blood vessels by cyclooxygenase-dependent mechanisms.

    PubMed

    Ogawa, Naoto; Mori, Asami; Hasebe, Masami; Hoshino, Maya; Saito, Maki; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2009-10-01

    It has been suggested that nitric oxide (NO) stimulates the cyclooxygenase (COX)-dependent mechanisms in the ocular vasculature; however, the importance of the pathway in regulating retinal circulation in vivo remains to be elucidated. Therefore, we investigated the role of COX-dependent mechanisms in NO-induced vasodilation of retinal blood vessels in thiobutabarbital-anesthetized rats with and without neuronal blockade (tetrodotoxin treatment). Fundus images were captured with a digital camera that was equipped with a special objective lens. The retinal vascular response was assessed by measuring changes in diameter of the retinal blood vessel. The localization of COX and soluble guanylyl cyclase in rat retina was examined using immunohistochemistry. The NO donors (sodium nitroprusside and NOR3) increased the diameter of the retinal blood vessels but decreased systemic blood pressure in a dose-dependent manner. Treatment of rats with indomethacin, a nonselective COX inhibitor, or SC-560, a selective COX-1 inhibitor, markedly attenuated the vasodilation of retinal arterioles, but not the depressor response, to the NO donors. However, both the vascular responses to NO donors were unaffected by the selective COX-2 inhibitors NS-398 and nimesulide. Indomethacin did not change the retinal vascular and depressor responses to hydralazine, 8-(4-chlorophenylthio)-guanosine-3', 5'-cyclic monophosphate (a membrane-permeable cGMP analog) and 8-(4-chlorophenylthio)-adenosine-3', 5'-cyclic monophosphate (a membrane-permeable cAMP analog). Treatment with SQ 22536, an adenylyl cyclase inhibitor, but not ODQ, a soluble guanylyl cyclase inhibitor, significantly attenuated the NOR3-induced vasodilation of retinal arterioles. The COX-1 immunoreactivity was found in retinal blood vessels. The retinal blood vessel was faintly stained for soluble guanylyl cyclase, although the apparent immunoreactivities on mesenteric and choroidal blood vessels were observed. These results suggest

  12. Evidence of Flicker-Induced Functional Hyperaemia in the Smallest Vessels of the Human Retinal Blood Supply.

    PubMed

    Duan, Angelina; Bedggood, Phillip A; Bui, Bang V; Metha, Andrew B

    2016-01-01

    Regional changes in blood flow are initiated within neural tissue to help fuel local differences in neural activity. Classically, this response was thought to arise only in larger arterioles and venules. However, recently, it has been proposed that a) the smallest vessels of the circulation make a comparable contribution, and b) the response should be localised intermittently along such vessels, due to the known distribution of contractile mural cells. To assess these hypotheses in human neural tissue in vivo, we imaged the retinal microvasculature (diameters 3-28 μm) non-invasively, using adaptive optics, before and after delivery of focal (360 μm) patches of flickering visible light. Our results demonstrated a definite average response in 35% of all vessel segments analysed. In these responding vessels, the magnitude of proportional dilation (mean ± SEM for pre-capillary arterioles 13 ± 5%, capillaries 31 ± 8%, and post-capillary venules 10 ± 3%) is generally far greater than the magnitudes we and others have measured in the larger retinal vessels, supporting proposition a) above. The dilations observed in venules were unexpected based on previous animal work, and may be attributed either to differences in stimulus or species. Response heterogeneity across the network was high; responses were also heterogeneous along individual vessels (45% of vessel segments showed demonstrable locality in their response). These observations support proposition b) above. We also observed a definite average constriction across 7% of vessel segments (mean ± SEM constriction for capillaries -16 ± 3.2%, and post-capillary venules -18 ± 12%), which paints a picture of dynamic redistribution of flow throughout the smallest vessel networks in the retina in response to local, stimulus-driven metabolic demand. PMID:27617960

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

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

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

    PubMed Central

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

    2007-01-01

    Background It 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 “random search strategy”, since it would increase the probability of being killed by their hosts. Indeed, heterogeneities along the skin surface might offer exploitable information for guiding insect's bites. Methodology/Principal Findings We tested whether the bug Rhodnius prolixus can evaluate temperature discontinuities along the body surface in order to locate vessels before piercing the host skin. When placed over a rabbit ear, the bug's first bites were mostly directed towards the main vessels. When insects were confronted to artificial linear heat sources presenting a temperature gradient against the background, most bites were directly addressed to the warmer linear source, notwithstanding the temperature of both, the source and the background. Finally, tests performed using uni- and bilaterally antennectomized insects revealed that the bilateral integration of thermal inputs from both antennae is necessary for precisely directing bites. Conclusions/Significance R. prolixus may be able to exploit the temperature differences observed over the skin surface to locate blood vessles. Bugs bite the warmest targets regardless of the target/background temperatures, suggesting that they do not bite choosing a preferred temperature, but select temperature discontinuities along the skin. This strategy seems to be an efficient one for finding blood vessels within a wide temperature range, allowing finding them on different hosts, as well as on different areas of the host body. Our study also adds new insight about the use of antennal thermal inputs by blood sucking bugs. PMID:17895973

  16. Differential Distribution of Blood and Lymphatic Vessels in the Murine Cornea

    PubMed Central

    Ecoiffier, Tatiana; Yuen, Don

    2010-01-01

    Purpose. Because of its unique characteristics, the cornea has been widely used for blood and lymphatic vessel research. However, whether limbal or corneal vessels are evenly distributed under normal or inflamed conditions has never been studied. The purpose of this study was to investigate this question and to examine whether and how the distribution patterns change during corneal inflammatory lymphangiogenesis (LG) and hemangiogenesis (HG). Methods. Corneal inflammatory LG and HG were induced in two most commonly used mouse strains, BALB/c and C57BL/6 (6–8 weeks of age), by a standardized two-suture placement model. Oriented flat-mount corneas together with the limbal tissues were used for immunofluorescence microscope studies. Blood and lymphatic vessels under normal and inflamed conditions were analyzed and quantified to compare their distributions. Results. The data demonstrate, for the first time, greater distribution of both blood and lymphatic vessels in the nasal side in normal murine limbal areas. This nasal-dominant pattern was maintained during corneal inflammatory LG, whereas it was lost for HG. Conclusions. Blood and lymphatic vessels are not evenly distributed in normal limbal areas. Furthermore, corneal LG and HG respond differently to inflammatory stimuli. These new findings will shed some light on corneal physiology and pathogenesis and on the development of experimental models and therapeutic strategies for corneal diseases. PMID:20019372

  17. Crosslinking of saphenous vein ECM by procyanidins for small diameter blood vessel replacement.

    PubMed

    Zhai, Wanyin; Zhang, Hongxia; Wu, Chengtie; Zhang, Jiamin; Sun, Xiaoning; Zhang, Hongfeng; Zhu, Ziyan; Chang, Jiang

    2014-08-01

    Xenogenic decellularized vessels, mainly composed of extracellular matrices (ECMs), are thought to be one of the alternative resources of small-diameter blood vessels due to abundant source, tubular configuration, vascular microstructure, and good cytocompatibility. However, the main shortcomings of ECM vessels are their low chemical stability, easy calcification, immunogenicity, and high risk of thrombogenicity. Previous studies have shown that, glutaraldehyde (GA), as a crosslinking agent, led to significant calcification and cytotoxicity for the prepared ECM substitutes. To overcome the drawbacks of pure and GA-crosslinked vascular alternatives of small-diameter blood vessels, procyanidins (PC), a naturally derived polyphenol with anti-inflammatory and platelet aggregation inhibiting bioactivities, was applied to crosslink the decellularized bovine saphenous vein ECM (svECM). After crosslinking, the obtained svECM substitutes exhibited natural tubular configuration with significantly improved mechanical properties, proper resistance to proteolysis, high chemical stability, and excellent anticalcification property. The PC-crosslinked svECM substitutes were cytocompatible for cells adhesion and proliferation, and blood compatible for erythrocytes with far less hemolysis than that of safety standard. Furthermore, the PC-crosslinked svECM substitutes showed distinct antithrombosis and anti-immunogenicity potential. With these advantages, it is suggested that the PC-crosslinked svECM may be used as a practical substitutes of small diameter blood vessels. PMID:24425308

  18. Image-guided optical measurement of blood oxygen saturation within capillary vessels (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Akons, Kfir; Zeidan, Adel; Yeheskely-Hayon, Daniella; Minai, Limor; Yelin, Dvir

    2016-03-01

    Values of blood oxygenation levels are useful for assessing heart and lung conditions, and are frequently monitored during routine patient care. Independent measurement of the oxygen saturation in capillary blood, which is significantly different from that of arterial blood, is important for diagnosing tissue hypoxia and for increasing the accuracy of existing techniques that measure arterial oxygen saturation. Here, we developed a simple, non-invasive technique for measuring the reflected spectra from individual capillary vessels within a human lip, allowing local measurement of the blood oxygen saturation. The optical setup includes a spatially incoherent broadband light that was focused onto a specific vessel below the lip surface. Backscattered light was imaged by a camera for identifying a target vessel and pointing the illumination beam to its cross section. Scattered light from the vessel was then collected by a single-mode fiber and analyzed by a fast spectrometer. Spectra acquired from small capillary vessels within a volunteer lip showed the characteristic oxyhemoglobin absorption bands in real time and with a high signal-to-noise ratio. Measuring capillary oxygen saturation using this technique would potentially be more accurate compared to existing pulse oximetry techniques due to its insensitivity to the patient's skin color, pulse rate, motion, and medical condition. It could be used as a standalone endoscopic technique for measuring tissue hypoxia or in conjunction with conventional pulse oximetry for a more accurate measurement of oxygen transport in the body.

  19. Probabilistic atlas based labeling of the cerebral vessel tree

    NASA Astrophysics Data System (ADS)

    Van de Giessen, Martijn; Janssen, Jasper P.; Brouwer, Patrick A.; Reiber, Johan H. C.; Lelieveldt, Boudewijn P. F.; Dijkstra, Jouke

    2015-03-01

    Preoperative imaging of the cerebral vessel tree is essential for planning therapy on intracranial stenoses and aneurysms. Usually, a magnetic resonance angiography (MRA) or computed tomography angiography (CTA) is acquired from which the cerebral vessel tree is segmented. Accurate analysis is helped by the labeling of the cerebral vessels, but labeling is non-trivial due to anatomical topological variability and missing branches due to acquisition issues. In recent literature, labeling the cerebral vasculature around the Circle of Willis has mainly been approached as a graph-based problem. The most successful method, however, requires the definition of all possible permutations of missing vessels, which limits application to subsets of the tree and ignores spatial information about the vessel locations. This research aims to perform labeling using probabilistic atlases that model spatial vessel and label likelihoods. A cerebral vessel tree is aligned to a probabilistic atlas and subsequently each vessel is labeled by computing the maximum label likelihood per segment from label-specific atlases. The proposed method was validated on 25 segmented cerebral vessel trees. Labeling accuracies were close to 100% for large vessels, but dropped to 50-60% for small vessels that were only present in less than 50% of the set. With this work we showed that using solely spatial information of the vessel labels, vessel segments from stable vessels (>50% presence) were reliably classified. This spatial information will form the basis for a future labeling strategy with a very loose topological model.

  20. Transient Non-Newtonian Blood Flow under Magnetic Targeting Drug Delivery in an Aneurysm Blood Vessel with Porous Walls

    NASA Astrophysics Data System (ADS)

    Alimohamadi, Haleh; Imani, Mohsen

    2014-11-01

    The present investigation deals with numerical solution of blood flow patterns through an aneurysm artery under the applied magnetic field. Transient extended Navier-Stokes, Brinkman, continuity, and heat conduction equations govern this phenomenon and unsteady pulsatile inlet velocity varies by human heart-beating frequency. Our simulation demonstrates applying 105 magnetic field intensity (MnF) to recirculate flow and increase fluid flux and maximum blood temperature by 62.5x and 3.5%, respectively, in the aneurysm region. It is also shown that the vessel's wall porosity plays an important role in magnetic targeting of drug delivery performance, as this parameter can noticeably change maximum blood temperature and pressure.

  1. Inclusion body myositis, muscle blood vessel and cardiac amyloidosis, and transthyretin Val122Ile allele.

    PubMed

    Askanas, V; Engel, W K; Alvarez, R B; Frangione, B; Ghiso, J; Vidal, R

    2000-04-01

    Typical of sporadic inclusion body myositis muscle biopsies are vacuolated muscle fibers containing intracellular amyloid deposits and accumulations of "Alzheimer-characteristic" proteins. There is no muscle blood vessel or cardiac amyloidosis. We report on a 70-year-old African-American man homozygous for the transthyretin Val122Ile allele who has both sporadic inclusion body myositis and cardiac amyloidosis. His unique pathological features included transthyretin immunoreactivity in prominent muscle blood vessel amyloid and congophilic amyloid deposits within vacuolated muscle fibers. PMID:10762172

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

    NASA Astrophysics Data System (ADS)

    Yi, Hou Hui

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

  3. Liver vessel segmentation based on extreme learning machine.

    PubMed

    Zeng, Ye Zhan; Zhao, Yu Qian; Liao, Miao; Zou, Bei Ji; Wang, Xiao Fang; Wang, Wei

    2016-05-01

    Liver-vessel segmentation plays an important role in vessel structure analysis for liver surgical planning. This paper presents a liver-vessel segmentation method based on extreme learning machine (ELM). Firstly, an anisotropic filter is used to remove noise while preserving vessel boundaries from the original computer tomography (CT) images. Then, based on the knowledge of prior shapes and geometrical structures, three classical vessel filters including Sato, Frangi and offset medialness filters together with the strain energy filter are used to extract vessel structure features. Finally, the ELM is applied to segment liver vessels from background voxels. Experimental results show that the proposed method can effectively segment liver vessels from abdominal CT images, and achieves good accuracy, sensitivity and specificity. PMID:27132031

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

    PubMed

    Miwa, Tomoyo; Mori, Asami; Nakahara, Tsutomu; Ishii, Kunio

    2009-01-01

    In the present study, we examined effects of intravenously administered inhibitors of phosphodiesterase 4 (rolipram and 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro-20-1724)) and non-selective inhibitor of phosphodiesterases (theophylline) on diameter of retinal blood vessel and fundus (retinal/choroidal) blood flow in rats. Male Wistar rats (8- to 10-week-old) were treated with tetrodotoxin (50 microg/kg, i.v.) to eliminate any nerve activity and prevent the eye movement under artificial ventilation. Methoxamine was used to maintain adequate systemic circulation. Ocular fundus images were captured with an original high-resolution digital fundus camera for small animals. Diameters of retinal blood vessels contained in the digital images were measured using image-processing softwares on a personal computer. Fundus blood flow was measured using a laser Doppler flow meter. Both rolipram (0.01-10 microg/kg/min, i.v.) and Ro-20-1724 (0.01-10 microg/kg/min, i.v.) increased diameters of retinal blood vessels in a dose-dependent manner without significant effect on systemic blood pressure, heart rate and fundus blood flow. The effects of phosphodiesterase 4 inhibitors on retinal arterioles were greater than those on retinal venules. Similarly, theophylline (0.1-10 mg/kg/min, i.v.) dilated retinal blood vessels, whereas it decreased blood pressure and increased heart rate markedly. These results suggest that phosphodiesterase 4 contributes to maintenance of retinal vascular tone. Inhibitors of phosphodiesterase 4 could be considered as a candidate for therapeutic drugs to treat diseases associated with disorders of retinal circulation without severe cardiovascular side-effects. PMID:19027003

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

    PubMed Central

    2014-01-01

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

  6. Laser-optical method of visualization the local net of tissue blood vessels and its biomedical applications

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

    New approach in laser-optical diagnostic methods of cell metabolism based on visualization the local net of tissue blood vessels is proposed. Optical model of laser - tissue interaction and algorithm of mathematical calculation of optical signals is developed. Novel technology of local tissue hypoxia elimination based on laser-induced photodissosiation of oxyhemoglobin in cutaneous blood vessels is developed. Method of determination of oxygen diffusion coefficient into tissue on the base of kinetics of tissue oxygenation TcPO II under the laser irradiation is proposed. The results of mathematical modeling the kinetic of oxygen distribution into tissue from arterial blood are presented. The possibility of calculation and determination of the level of TcPO II in zones with the disturbed blood microcirculation is demonstrated. The increase of the value of oxygen release rate more than for times under the irradiation by laser light is obtained. It is shown that the efficiency of laser-induced oxygenation by means of increasing oxygen concentration in blood plasma is comparable with the method of hyperbaric oxygenation (HBO) at the same time gaining advantages in local action. Different biomedical applications of developing method are discussed.

  7. Acrylic resin injection method for blood vessel investigations.

    PubMed

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  9. Peristaltic Pumping of Blood Through Small Vessels of Varying Cross-Section

    NASA Astrophysics Data System (ADS)

    Misra, J. C.; Maiti, S.

    2012-11-01

    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.

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

    PubMed

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

    2001-04-01

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

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

    PubMed Central

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

    2012-01-01

    The blood vessels of cancerous tumours are leaky1–3 and poorly organized4–7. This can increase the interstitial fluid pressure (IFP) inside tumours and reduce blood supply to them, which impairs drug delivery8–9. Anti-angiogenic therapies – which “normalize” the abnormal blood vessels in tumours by making them less leaky – have been shown to improve the delivery and effectiveness of chemotherapeutics with low molecular-weights10, but it remains unclear whether normalizing tumour vessels can improve the delivery of nanomedicines. Here we show that repairing the abnormal vessels in mammary tumours, by blocking vascular endothelial growth factor (VEGF) receptor-2, improves the delivery of small nanoparticles (12nm diameter) while hindering the delivery of large nanoparticles (125nm diameter). We utilize a mathematical model to show that reducing vessel wall pore sizes through normalization decreases IFP in tumours, allowing small nanoparticles to enter them more rapidly. However, increased steric and hydrodynamic hindrances, also associated with smaller pores, make it more difficult for large nanoparticles to enter tumours. Our results further suggest that smaller (~12nm) nanomedicines are ideal for cancer therapy, owing to superior tumour penetration. PMID:22484912

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

    PubMed Central

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

    2008-01-01

    Mechanical models have potential to guide the development and use of engineered blood vessels as well as other engineered tissues. This paper presents a microstructurally motivated, pseudoelastic, mechanical model of the biaxial mechanics of engineered vessels in the physiologic pressure range. The model incorporates experimentally measured densities and alignments of engineered collagen. Specifically, these microstructural and associated mechanical inputs were measured directly from engineered blood vessels that were cultured over periods of 5–7.5 weeks. To the best of our knowledge, this is the first successful application of either a phenomenological or a microstructurally motivated mechanical model to engineered vascular tissues. Model development revealed the need to use novel theoretical configurations to describe the strain history of engineered vessels. The constitutive equations developed herein suggested that collagen remodeled between 5 and 7.5 weeks during a 7.5-week culture period. This remodeling led to strain energies for collagen that differed with alignment, which likely resulted from undulations that varied with alignment. Finally, biaxial data emphasized that axial extensions increase stresses in engineered vessels in the physiologic pressure range, thereby providing a guideline for surgical use: engineered vessels should be implanted at appropriate axial extension to minimize adverse stress responses. PMID:18720007

  13. Imaging functional blood vessels by the laser speckle imaging (LSI) technique using Q-statistics of the generalized differences algorithm.

    PubMed

    Ansari, Mohammad Zaheer; Cabrera, Humberto; Ramírez-Miquet, Evelio E

    2016-09-01

    In this work, we report about q statistics concept to improve the performance of generalized differences algorithm based on intensity histogram for imaging functional blood vessel structures in a rodent window chamber of a mice. The method uses the dynamic speckle signals obtained by transilluminating the rodent window chamber to create activity maps of vasculatures. The proposed method of generalized differences with q statistics (GDq) is very sensitive to the values of defined parameters such as: camera exposure time, the q value and the camera frame number. Appropriate choice of q values enhances the visibility (contrast) of functional blood vessels but at the same time without sacrificing the spatial resolution, which is of utmost importance for in-vivo vascular imaging. PMID:27154269

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    PubMed

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

    1966-09-01

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

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

    PubMed

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

    2014-02-01

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

  17. Making Ends Meet: Myeloid Cells Catalyze Blood Vessel Repair in the Brain.

    PubMed

    Deczkowska, Aleksandra; Schwartz, Michal

    2016-05-17

    Hemorrhagic stroke, primarily caused by rupture of blood vessels in the brain, is a leading cause of death and disability in adults. In this issue of Immunity, Liu et al. (2016) demonstrate that repair of cerebrovascular ruptures can be directly mediated by myeloid cells. PMID:27192572

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

    PubMed

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

    2008-01-01

    We describe a protocol to rapidly and reliably visualize blood vessels in experimental animals. Blood vessels are directly labeled by cardiac perfusion using a specially formulated aqueous solution containing 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI), a lipophilic carbocyanine dye, which incorporates into endothelial cell membranes upon contact. By lateral diffusion, DiI also stains membrane structures, including angiogenic sprouts and pseudopodial processes that are not in direct contact. Tissues can be immediately examined by conventional and confocal fluorescence microscopy. High-quality serial optical sections using confocal microscopy are obtainable from thick tissue sections, especially at low magnification, for three-dimensional reconstruction. It takes less than 1 h to stain the vasculature in a whole animal. Compared with alternative techniques to visualize blood vessels, including space-occupying materials such as India ink or fluorescent dye-conjugated dextran, the corrosion casting technique, endothelial cell-specific markers and lectins, the present method simplifies the visualization of blood vessels and data analysis. PMID:18846097

  19. Enhanced bonding strength of hydrophobically modified gelatin films on wet blood vessels.

    PubMed

    Yoshizawa, Keiko; Taguchi, Tetsushi

    2014-01-01

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

  20. Transdermal drug targeting and functional imaging of tumor blood vessels in the mouse auricle.

    PubMed

    Schröder, Hannes; Komljenovic, Dorde; Hecker, Markus; Korff, Thomas

    2016-02-01

    Subcutaneously growing tumors are widely utilized to study tumor angiogenesis and the efficacy of antiangiogenic therapies in mice. To additionally assess functional and morphologic alterations of the vasculature in the periphery of a growing tumor, we exploited the easily accessible and hierarchically organized vasculature of the mouse auricle. By site-specific subcutaneous implantation of a defined preformed mouse B16/F0 melanoma aggregate, a solid tumor nodule developed within 14 d. Growth of the tumor nodule was accompanied by a 4-fold increase in its perfusion as well as a 2- to 4-fold elevated diameter and perfusion of peripheral blood vessels that had connected to the tumor capillary microvasculature. By transdermal application of the anticancer drug bortezomib, tumor growth was significantly diminished by about 50% without provoking side effects. Moreover, perfusion and tumor microvessel diameter as well as growth and perfusion of arterial or venous blood vessels supplying or draining the tumor microvasculature were decreased under these conditions by up to 80%. Collectively, we observed that the progressive tumor growth is accompanied by the enlargement of supplying and draining extratumoral blood vessels. This process was effectively suppressed by bortezomib, thereby restricting the perfusion capacity of both extra and intratumoral blood vessels. PMID:26546130

  1. Blood vessel reconstruction from a limited number of cone-beam projections: application to cerebral blood vessel projections and to an excised animal heart

    NASA Astrophysics Data System (ADS)

    Robert, Normand; Peyrin, Francoise; Yaffe, Martin J.

    1995-05-01

    Visual assessment of arterial lesions from angiograms is subject to considerable inter- and intra-observer variability. To overcome these limitations, we are developing a method to perform reconstruction of vascular cross-sectional images from a limited number of x-ray angiographic cone-beam projections. The projection data are simplified by identifying blood vessels in each angiogram and removing signals due to other structures. The reconstruction is performed using the method of simulated annealing. An application of this approach to projections of cerebral vessels obtained from segmented CT slices of a cadaver injected with contrast agent are shown. We have also reconstructed an excised animal heart in order to test our method under more realistic image acquisition conditions including scatter, beam hardening, and variations in background signal.

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

    NASA Astrophysics Data System (ADS)

    Maiti, S.; Misra, J. C.

    2013-08-01

    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 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.

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

    PubMed

    Arieli, R; Marmur, A

    2013-08-01

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

  4. Ovarian angiogenesis. Phenotypic characterization of endothelial cells in a physiological model of blood vessel growth and regression.

    PubMed Central

    Augustin, H. G.; Braun, K.; Telemenakis, I.; Modlich, U.; Kuhn, W.

    1995-01-01

    Angiogenesis occurs during embryogenesis and is a down-regulated process in the healthy adult that is almost exclusively linked to pathological conditions such as tumor growth, wound healing, and inflammation. Physiological angiogenic processes in the adult are restricted to the female reproductive system where they occur cyclically during the ovarian and uterine cycle as well as during pregnancy. By systematically analyzing the phenotypic changes of endothelial cells during bovine corpus luteum (CL) formation and regression, we have established a physiological model of blood vessel growth and regression. Quantitation of vessel density, percentage of vessels with lumen, and ratio of Bandeiraea simplicifolia-I to von Willebrand Factor-positive endothelial cells were established as parameters of angiogenesis. Sprouting endothelial cells invade the growing CL and continue to grow throughout the first third of the ovarian cycle. Thereafter the mature CL is characterized by a dense network of vessels with gradually decreasing vessel density. During luteolysis and for several weeks thereafter (regressing and residual CL) all newly formed vessels regress, which is accompanied by gradual foreshortening and rounding of endothelial cells and subsequent detachment. Based on histochemical detection of nucleosomal fragmentation products physiological blood vessel regression in the cyclic CL does not appear to involve endothelial cell apoptosis. Lectin histochemical analysis revealed a distinct alteration of endothelial cell glycoconjugate expression during ovarian angiogenesis comparable with the distinct pattern of hyperglycosylation of cultured migrating endothelial cells (up-regulation of binding sites for Lycopersicon esculentum lectin, wheat germ agglutinin, neuraminidase-treated peanut agglutinin, and Ricinus communis agglutinin-I on sprouting ECs). Northern blot analysis of glycosyltransferases during the different stages of angiogenesis revealed an up-regulation of beta

  5. On ultrasound-induced microbubble oscillation in a capillary blood vessel and its implications for the blood-brain barrier

    NASA Astrophysics Data System (ADS)

    Wiedemair, W.; Tuković, Ž.; Jasak, H.; Poulikakos, D.; Kurtcuoglu, V.

    2012-02-01

    The complex interaction between an ultrasound-driven microbubble and an enclosing capillary microvessel is investigated by means of a coupled, multi-domain numerical model using the finite volume formulation. This system is of interest in the study of transient blood-brain barrier disruption (BBBD) for drug delivery applications. The compliant vessel structure is incorporated explicitly as a distinct domain described by a dedicated physical model. Red blood cells (RBCs) are taken into account as elastic solids in the blood plasma. We report the temporal and spatial development of transmural pressure (Ptm) and wall shear stress (WSS) at the luminal endothelial interface, both of which are candidates for the yet unknown mediator of BBBD. The explicit introduction of RBCs shapes the Ptm and WSS distributions and their derivatives markedly. While the peak values of these mechanical wall parameters are not affected considerably by the presence of RBCs, a pronounced increase in their spatial gradients is observed compared to a configuration with blood plasma alone. The novelty of our work lies in the explicit treatment of the vessel wall, and in the modelling of blood as a composite fluid, which we show to be relevant for the mechanical processes at the endothelium.

  6. Low-dose 2D X-ray angiography enhancement using 2-axis PCA for the preservation of blood-vessel region and noise minimization.

    PubMed

    Lee, Yong Geun; Lee, Jeongjin; Shin, Yeong-Gil; Kang, Ho Chul

    2016-01-01

    Enhancing 2D angiography while maintaining a low radiation dose has become an important research topic. However, it is difficult to enhance images while preserving vessel-structure details because X-ray noise and contrast blood vessels in 2D angiography have similar intensity distributions, which can lead to ambiguous images of vessel structures. In this paper, we propose a novel and fast vessel-enhancement method for 2D angiography. We apply filtering in the principal component analysis domain for vessel regions and background regions separately, using assumptions based on energy compaction. First, we identify an approximate vessel region using a Hessian-based method. Vessel and non-vessel regions are then represented sparsely by calculating their optimal bases separately. This is achieved by identifying periodic motion in the vessel region caused by the flow of the contrast medium through the blood vessels when viewed on the time axis. Finally, we obtain noise-free images by removing noise in the new coordinate domain for the optimal bases. Our method was validated for an X-ray system, using 10 low-dose sets for training and 20 low-dose sets for testing. The results were compared with those for a high-dose dataset with respect to noise-free images. The average enhancement rate was 93.11±0.71%. The average processing time for enhancing video comprising 50-70 frames was 0.80±0.35s, which is much faster than the previously proposed technique. Our method is applicable to 2D angiography procedures such as catheterization, which requires rapid and natural vessel enhancement. PMID:26483302

  7. 3-D Ultrafast Doppler Imaging Applied to the Noninvasive and Quantitative Imaging of Blood Vessels in Vivo

    PubMed Central

    Provost, J.; Papadacci, C.; Demene, C.; Gennisson, J-L.; Tanter, M.; Pernot, M.

    2016-01-01

    Ultrafast Doppler Imaging was introduced as a technique to quantify blood flow in an entire 2-D field of view, expanding the field of application of ultrasound imaging to the highly sensitive anatomical and functional mapping of blood vessels. We have recently developed 3-D Ultrafast Ultrasound Imaging, a technique that can produce thousands of ultrasound volumes per second, based on three-dimensional plane and diverging wave emissions, and demonstrated its clinical feasibility in human subjects in vivo. In this study, we show that non-invasive 3-D Ultrafast Power Doppler, Pulsed Doppler, and Color Doppler Imaging can be used to perform quantitative imaging of blood vessels in humans when using coherent compounding of three-dimensional tilted plane waves. A customized, programmable, 1024-channel ultrasound system was designed to perform 3-D Ultrafast Imaging. Using a 32X32, 3-MHz matrix phased array (Vermon, France), volumes were beamformed by coherently compounding successive tilted plane wave emissions. Doppler processing was then applied in a voxel-wise fashion. 3-D Ultrafast Power Doppler Imaging was first validated by imaging Tygon tubes of varying diameter and its in vivo feasibility was demonstrated by imaging small vessels in the human thyroid. Simultaneous 3-D Color and Pulsed Doppler Imaging using compounded emissions were also applied in the carotid artery and the jugular vein in one healthy volunteer. PMID:26276956

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

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

    PubMed

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

    2014-12-28

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

  10. Assembly of trunk and limb blood vessels involves extensive migration and vasculogenesis of somite-derived angioblasts.

    PubMed

    Ambler, C A; Nowicki, J L; Burke, A C; Bautch, V L

    2001-06-15

    Vascular development requires the assembly of precursor cells into blood vessels, but how embryonic vessels are assembled is not well understood. To determine how vascular cells migrate and assemble into vessels of the trunk and limb, marked somite-derived angioblasts were followed in developing embryos. Injection of avian somites with the cell-tracker DiI showed that somite-derived angioblasts in unperturbed embryos migrated extensively and contributed to trunk and limb vessels. Mouse-avian chimeras with mouse presomitic mesoderm grafts had graft-derived endothelial cells in blood vessels at significant distances from the graft, indicating that mouse angioblasts migrated extensively in avian hosts. Mouse graft-derived endothelial cells were consistently found in trunk vessels, such as the perineural vascular plexus, the cardinal vein, and presumptive intersomitic vessels, as well as in vessels of the limb and kidney rudiment. This reproducible pattern of graft colonization suggests that avian vascular patterning cues for trunk and limb vessels are recognized by mammalian somitic angioblasts. Mouse-quail chimeras stained with both the quail vascular marker QH1 and the mouse vascular marker PECAM-1 had finely chimeric vessels, with graft-derived mouse cells interdigitated with quail vascular cells in most vascular beds colonized by graft cells. Thus, diverse trunk and limb blood vessels have endothelial cells that developed from migratory somitic angioblasts, and assembly of these vessels is likely to have a large vasculogenic component. PMID:11397005

  11. Adaptive ultrasonic measurement of blood vessel diameter and wall thickness: theory and experimental results.

    PubMed

    Rafii, K; Jaffe, J S

    1998-01-01

    An adaptive ultrasonic technique for measuring blood vessel diameter and wall thickness is presented. This technique allows one to use a target-specific transmitted waveform/receiver filter to obtain a larger signal-to-noise ratio (SNR) in the received signal than conventional techniques. Generally, SNR of a received wave increases as the intensity of the transmit wave increases; however, because of the FDA limitations placed on the amount of transmit energy, it is important to be able to make the most efficient use of the energy that is available to obtain the best possible SNR in the received signal. Adaptive ultrasonic measurement makes the most efficient use of the energy that is available by placing the maximum amount of energy in the largest target scattering mode. This results in more energy backscatter from a given target, which leads to a higher SNR in the received waveform. Computer simulations of adaptive ultrasonic measurement of blood vessel diameter show that for a SNR of 0 dB in the transmitted waveform, the standard deviation of the diameter measurements for a custom-designed transmitted waveform is about two orders of magnitude less than the standard deviation of the diameter measurements using more conventional waveforms. Diameter and wall thickness measurement experiments were performed on a latex tube and a bovine blood vessel using both custom-made and conventionally used transmitted waveforms. Results show that the adaptively designed waveform gives a smaller uncertainty in the measurements. The adaptive ultrasonic blood vessel diameter and wall thickness measuring technique has potential applications in examining vessels which are either too deep inside the body or too small for conventional techniques to be used, because of the low SNR in the received signal. PMID:18244211

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  13. Engineering blood vessels using stem cells: innovative approaches to treat vascular disorders.

    PubMed

    Kusuma, Sravanti; Gerecht, Sharon

    2010-10-01

    Vascular disease is the leading cause of mortality in the USA, providing the impetus for new treatments and technologies. Current therapies rely on the implantation of stents or grafts to treat injured blood vessels. However, these therapies may be immunogenic or may incompletely recover the functional integrity of the vasculature. In light of these shortcomings, cell-based therapies provide new treatment options to heal damaged areas with more suitable substitutes. Current clinical trials employing stem cell-based therapies involve the transfusion of harvested endothelial progenitor cells. While the results from these trials have been encouraging, utilizing tissue-engineered approaches could yield technologically advanced solutions. This article discusses engineered stem cell-based therapies from three angles: the differentiation of adult stem cells, such as mesenchymal stem cells and endothelial progenitor cells, into vascular lineages; investigation of human embryonic stem cells and induced pluripotent stem cells as inexhaustible sources of vascular cells; and tissue-engineering approaches, which incorporate these vascular progenitor cells into biomimetic scaffolds to guide regeneration. The optimal solution to vascular disease lies at the interface of these technologies--embedding differentiated cells into engineered scaffolds to impart precise control over vascular regeneration. PMID:20936930

  14. Active Path Selection of Fluid Microcapsules in Artificial Blood Vessel by Acoustic Radiation Force

    NASA Astrophysics Data System (ADS)

    Masuda, Kohji; Muramatsu, Yusuke; Ueda, Sawami; Nakamoto, Ryusuke; Nakayashiki, Yusuke; Ishihara, Ken

    2009-07-01

    Micrometer-sized microcapsules collapse upon exposure to ultrasound. Use of this phenomenon for a drug delivery system (DDS), not only for local delivery of medication but also for gene therapy, should be possible. However, enhancing the efficiency of medication is limited because capsules in suspension diffuse in the human body after injection, since the motion of capsules in blood flow cannot be controlled. To control the behavior of microcapsules, acoustic radiation force was introduced. We detected local changes in microcapsule density by producing acoustic radiation force in an artificial blood vessel. Furthermore, we theoretically estimated the conditions required for active path selection of capsules at a bifurcation point in the artificial blood vessel. We observed the difference in capsule density at both in the bifurcation point and in alternative paths downstream of the bifurcation point for different acoustic radiation forces. Comparing the experimental results with those obtained theoretically, the conditions for active path selection were calculated from the acoustic radiation force and fluid resistance of the capsules. The possibility of controlling capsule flow towards a specific point in a blood vessel was demonstrated.

  15. On the Role of the Blood Vessel Endothelial Microvilli in the Blood Flow in Small Capillaries

    PubMed Central

    Makarov, Vladimir; Zueva, Lidia; Sanabria, Priscila; Wessinger, William Dave; Golubeva, Tatiana; Khmelinskii, Igor; Inyushin, Mikhail

    2015-01-01

    Endothelial microvilli that protrude into the capillary lumen, although invisible in the optical microscopy, may play an important role in the blood flow control in the capillaries. Because of the plug effects, the width of the gap between the capillary wall and the blood cell is especially critical for the blood flow dynamics in capillaries, while microvilli located on the capillary wall can easily control the velocity of the blood flow. We report that microvilli in the capillaries of different vertebrate species have similar characteristics and density, suggesting similarities between the respective regulation mechanisms. A simplified physical model of the capillary effective diameter control by the microvilli is presented. PMID:26604921

  16. [Effect of amlodipine, a new calcium antagonist on isolated blood vessels].

    PubMed

    Yamanaka, K; Suzuki, M; Munehasu, S; Ishiko, J

    1991-03-01

    Amlodipine (AML), a new 1,4-dihydropyridine derivative, similar to nifedipine (NIF), dose-dependently relaxed or inhibited the KCL-contraction (cont.) of dog coronary artery (DCA) and rat aorta (RA) and the spontaneous motility of rat portal vein (RPV). However, in contrast to the case of NIF, the maximum effect was obtained at 1-2 hr following an addition of AML, and the recovery of KCl-cont. after removal of AML was very slow. Similar effects of AML on KCl-cont. were observed in dog femoral artery (DFA), dog basilar artery (DBA) and rabbit aorta (RBA). The IC50 values of AML for producing the half-maximal effect were 6.5 x 10(-9) M, 6.5 x 10(-9) M, 1.1 x 10(-8) M, 1.7 x 10(-8) M and 4.8 x 10(-8) M in DCA, DFA, RPV, DBA and RBA, respectively. In these vessels, the potency of AML was slightly less than the potency of NIF. On the other hand, AML (10(-7), 10(-6) M) only slightly attenuated norepinephrine (NE)-induced cont. in DFA and RA. Based on the ratio of IC50 values in DFA, AML exhibited 846-fold higher selectivity toward KCl-cont. than NE-cont., and it was much higher than the selectivity of NIF. In calcium-free medium, AML failed to inhibit the NE-cont. in RA, but it markedly inhibited CaCl2-induced cont. These results indicate that AML significantly inhibits KCl-cont. in blood vessels at lower doses with slightly less potency than NIF, but with a higher selectivity than NIF in comparison with the potency against NE-cont., and they also confirmed that the effect of AML is of slow onset and long-lasting. PMID:1828241

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

    NASA Astrophysics Data System (ADS)

    Sills, Tiffany M.; Hirschi, Karen K.

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

  18. Vascular Patterns in Iguanas and Other Squamates: Blood Vessels and Sites of Thermal Exchange.

    PubMed

    Porter, William Ruger; Witmer, Lawrence M

    2015-01-01

    Squamates use the circulatory system to regulate body and head temperatures during both heating and cooling. The flexibility of this system, which possibly exceeds that of endotherms, offers a number of physiological mechanisms to gain or retain heat (e.g., increase peripheral blood flow and heart rate, cooling the head to prolong basking time for the body) as well as to shed heat (modulate peripheral blood flow, expose sites of thermal exchange). Squamates also have the ability to establish and maintain the same head-to-body temperature differential that birds, crocodilians, and mammals demonstrate, but without a discrete rete or other vascular physiological device. Squamates offer important anatomical and phylogenetic evidence for the inference of the blood vessels of dinosaurs and other extinct archosaurs in that they shed light on the basal diapsid condition. Given this basal positioning, squamates likewise inform and constrain the range of physiological thermoregulatory mechanisms that may have been found in Dinosauria. Unfortunately, the literature on squamate vascular anatomy is limited. Cephalic vascular anatomy of green iguanas (Iguana iguana) was investigated using a differential-contrast, dual-vascular injection (DCDVI) technique and high-resolution X-ray microcomputed tomography (μCT). Blood vessels were digitally segmented to create a surface representation of vascular pathways. Known sites of thermal exchange, consisting of the oral, nasal, and orbital regions, were given special attention due to their role in brain and cephalic thermoregulation. Blood vessels to and from sites of thermal exchange were investigated to detect conserved vascular patterns and to assess their ability to deliver cooled blood to the dural venous sinuses. Arteries within sites of thermal exchange were found to deliver blood directly and through collateral pathways. The venous drainage was found to have multiple pathways that could influence neurosensory tissue temperature

  19. Vascular Patterns in Iguanas and Other Squamates: Blood Vessels and Sites of Thermal Exchange

    PubMed Central

    Porter, William Ruger; Witmer, Lawrence M.

    2015-01-01

    Squamates use the circulatory system to regulate body and head temperatures during both heating and cooling. The flexibility of this system, which possibly exceeds that of endotherms, offers a number of physiological mechanisms to gain or retain heat (e.g., increase peripheral blood flow and heart rate, cooling the head to prolong basking time for the body) as well as to shed heat (modulate peripheral blood flow, expose sites of thermal exchange). Squamates also have the ability to establish and maintain the same head-to-body temperature differential that birds, crocodilians, and mammals demonstrate, but without a discrete rete or other vascular physiological device. Squamates offer important anatomical and phylogenetic evidence for the inference of the blood vessels of dinosaurs and other extinct archosaurs in that they shed light on the basal diapsid condition. Given this basal positioning, squamates likewise inform and constrain the range of physiological thermoregulatory mechanisms that may have been found in Dinosauria. Unfortunately, the literature on squamate vascular anatomy is limited. Cephalic vascular anatomy of green iguanas (Iguana iguana) was investigated using a differential-contrast, dual-vascular injection (DCDVI) technique and high-resolution X-ray microcomputed tomography (μCT). Blood vessels were digitally segmented to create a surface representation of vascular pathways. Known sites of thermal exchange, consisting of the oral, nasal, and orbital regions, were given special attention due to their role in brain and cephalic thermoregulation. Blood vessels to and from sites of thermal exchange were investigated to detect conserved vascular patterns and to assess their ability to deliver cooled blood to the dural venous sinuses. Arteries within sites of thermal exchange were found to deliver blood directly and through collateral pathways. The venous drainage was found to have multiple pathways that could influence neurosensory tissue temperature

  20. Usefulness of dilated blood vessels in the tumor periphery for assessing the invasion depth of small-sized depressed colorectal cancer

    PubMed Central

    Hashimoto, Rintaro; Matsuda, Tomoki; Hamamoto, Hidetaka; Yamaoka, Hajime; Nakahori, Masato; Chonan, Akimichi

    2016-01-01

    Abstract The relationship between dilated blood vessels in the tumor periphery and the tumor invasion depth is unclear. Therefore, the present study aimed to clarify the relationship between dilated blood vessels and the invasion depth of small-sized (<30 mm) colorectal cancer (CRC), and its implications on endoscopic treatment. We performed a single-arm observational study of the diagnostic accuracy of the existence of dilated vessels in the tumor periphery of CRC lesions as an indicator of submucosal deep (SM-d, ≥1000 μm) carcinomas. Lesions were classified into two groups based on the existence of dilated vessels by two experienced endoscopists. The clinicopathological features, invasion depth, and lymphovascular invasion/poorly differentiated clusters were analyzed in all resected specimens. Four hundred and two consecutive small-sized CRC lesions were included. The dilated vessels were observed in 96/402 (24%) lesions, and most of them (93/96) were found in depressed lesions. In depressed lesions, the histopathological diagnosis of the dilated vessels group showed SM-d or deeper invasion in 84/93 (90%) cases, whereas 3/20 (15%) had SM-d invasion in the nondilated vessels group (P < 0.001). When the dilated vessels were used as an indicator of SM-d or deeper invasion in depressed lesions, the sensitivity was 95.6%, specificity was 66.7%, and accuracy was 90.2%. No correlation was observed between the existence of dilated vessels and the lesion site, lesion diameter, and lymphovascular invasion/poorly differentiated cluster. The existence of dilated blood vessels in the tumor periphery suggests SM-d or deeper invasion in depressed lesions. PMID:27336879

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

    PubMed Central

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

    1971-01-01

    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

  2. Synchronization of endothelial Dll4-Notch dynamics switch blood vessels from branching to expansion.

    PubMed

    Ubezio, Benedetta; Blanco, Raquel Agudo; Geudens, Ilse; Stanchi, Fabio; Mathivet, Thomas; Jones, Martin L; Ragab, Anan; Bentley, Katie; Gerhardt, Holger

    2016-01-01

    Formation of a regularly branched blood vessel network is crucial in development and physiology. Here we show that the expression of the Notch ligand Dll4 fluctuates in individual endothelial cells within sprouting vessels in the mouse retina in vivo and in correlation with dynamic cell movement in mouse embryonic stem cell-derived sprouting assays. We also find that sprout elongation and branching associates with a highly differential phase pattern of Dll4 between endothelial cells. Stimulation with pathologically high levels of Vegf, or overexpression of Dll4, leads to Notch dependent synchronization of Dll4 fluctuations within clusters, both in vitro and in vivo. Our results demonstrate that the Vegf-Dll4/Notch feedback system normally operates to generate heterogeneity between endothelial cells driving branching, whilst synchronization drives vessel expansion. We propose that this sensitive phase transition in the behaviour of the Vegf-Dll4/Notch feedback loop underlies the morphogen function of Vegfa in vascular patterning. PMID:27074663

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

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

    PubMed Central

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

    2014-01-01

    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

  5. Blood vessels pattern heparan sulfate gradients between their apical and basolateral aspects.

    PubMed

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

    2014-01-01

    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

  6. Blood vessel uptake and metabolism of organic nitrates in the rat.

    PubMed

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

    1984-02-01

    Recent reports have suggested that the unusual pharmacokinetics observed for nitroglycerin (NTG) and isosorbide dinitrate (ISDN) may be partially explained by extensive uptake and/or metabolism of these drugs by vascular and other extrahepatic tissues. Using the rat as an animal model, this hypothesis was examined by in vivo intravessel NTG and [14C]ISDN infusion and injection into various vessel segments, viz. the femoral vein, inferior vena cava [IVC: lower, middle and upper) and the aorta. NTG and [14C]ISDN concentrations were determined in these blood vessels and in plasma. Blood vessel segments nearest the input site had the greatest amounts of nitrate, whereas segments further away from the input site had progressively less nitrate, with the exception of aorta, which appeared to take up NTG less extensively, on a per weight of vessel basis, than the IVC. Blood vessel NTG concentrations (nanogram per gram) were generally higher (10-fold) and declined about twice as slowly as NTG plasma concentrations (nanograms per milliliter). [14C]NTG and [14C]ISDN were also incubated with cofactors in IVC, aorta, abdominal muscle, lung and liver. The amounts of nitrate metabolites formed from parent drug were larger in each extrahepatic tissue incubation than in the controls (P less than .05). The results are consistent with the hypothesis that vascular and other extrahepatic tissues can take up and/or metabolize organic nitrates. The data appear to provide a partial explanation for the large systemic clearance seen with nitrates and appear consistent with existing mechanistic hypotheses for the vascular action of these compounds. PMID:6420543

  7. Excess centrosomes perturb dynamic endothelial cell repolarization during blood vessel formation

    PubMed Central

    Kushner, Erich J.; Ferro, Luke S.; Yu, Zhixian; Bautch, Victoria L.

    2016-01-01

    Blood vessel formation requires dynamic movements of endothelial cells (ECs) within sprouts. The cytoskeleton regulates migratory polarity, and centrosomes organize the microtubule cytoskeleton. However, it is not well understood how excess centrosomes, commonly found in tumor stromal cells, affect microtubule dynamics and interphase cell polarity. Here we find that ECs dynamically repolarize during sprouting angiogenesis, and excess centrosomes block repolarization and reduce migration and sprouting. ECs with excess centrosomes initially had more centrosome-derived microtubules but, paradoxically, fewer steady-state microtubules. ECs with excess centrosomes had elevated Rac1 activity, and repolarization was rescued by blockade of Rac1 or actomyosin blockers, consistent with Rac1 activity promoting cortical retrograde actin flow and actomyosin contractility, which precludes cortical microtubule engagement necessary for dynamic repolarization. Thus normal centrosome numbers are required for dynamic repolarization and migration of sprouting ECs that contribute to blood vessel formation. PMID:27099371

  8. In Vivo μPIV Measurements of Blood Flow in Small Vessels of a Rat Model.

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

  9. Three-Dimensional Reconstruction of Blood Vessels of the Human Retina by Fractal Interpolation

    PubMed Central

    Guedri, Hichem; Malek, Jihen; Belmabrouk, Hafedh

    2015-01-01

    In this work, data from two-dimensional (2D) images of the human retina were taken as a case study. First, the characteristic data points had been removed using the Douglas–Peucker (DP) method, and subsequently, more data points were added using random fractal interpolation approach, to reconstruct a three-dimensional (3D) model of the blood vessel. By visualizing the result, we can see that all the small blood vessels in the human retina are more visible and detailed. This algorithm of 3D reconstruction has the advantage of being fast with calculation time less than 40 s and also can reduce the 3D image storage level on a disk with a reduction ratio between 78% and 96.65%. PMID:27222695

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  11. Regulation of monocyte cell fate by blood vessels mediated by Notch signalling.

    PubMed

    Gamrekelashvili, Jaba; Giagnorio, Roberto; Jussofie, Jasmin; Soehnlein, Oliver; Duchene, Johan; Briseño, Carlos G; Ramasamy, Saravana K; Krishnasamy, Kashyap; Limbourg, Anne; Kapanadze, Tamar; Ishifune, Chieko; Hinkel, Rabea; Radtke, Freddy; Strobl, Lothar J; Zimber-Strobl, Ursula; Napp, L Christian; Bauersachs, Johann; Haller, Hermann; Yasutomo, Koji; Kupatt, Christian; Murphy, Kenneth M; Adams, Ralf H; Weber, Christian; Limbourg, Florian P

    2016-01-01

    A population of monocytes, known as Ly6C(lo) monocytes, patrol blood vessels by crawling along the vascular endothelium. Here we show that endothelial cells control their origin through Notch signalling. Using combinations of conditional genetic deletion strategies and cell-fate tracking experiments we show that Notch2 regulates conversion of Ly6C(hi) monocytes into Ly6C(lo) monocytes in vivo and in vitro, thereby regulating monocyte cell fate under steady-state conditions. This process is controlled by Notch ligand delta-like 1 (Dll1) expressed by a population of endothelial cells that constitute distinct vascular niches in the bone marrow and spleen in vivo, while culture on recombinant DLL1 induces monocyte conversion in vitro. Thus, blood vessels regulate monocyte conversion, a form of committed myeloid cell fate regulation. PMID:27576369

  12. Accurate 3D reconstruction of complex blood vessel geometries from intravascular ultrasound images: in vitro study.

    PubMed

    Subramanian, K R; Thubrikar, M J; Fowler, B; Mostafavi, M T; Funk, M W

    2000-01-01

    We present a technique that accurately reconstructs complex three dimensional blood vessel geometry from 2D intravascular ultrasound (IVUS) images. Biplane x-ray fluoroscopy is used to image the ultrasound catheter tip at a few key points along its path as the catheter is pulled through the blood vessel. An interpolating spline describes the continuous catheter path. The IVUS images are located orthogonal to the path, resulting in a non-uniform structured scalar volume of echo densities. Isocontour surfaces are used to view the vessel geometry, while transparency and clipping enable interactive exploration of interior structures. The two geometries studied are a bovine artery vascular graft having U-shape and a constriction, and a canine carotid artery having multiple branches and a constriction. Accuracy of the reconstructions is established by comparing the reconstructions to (1) silicone moulds of the vessel interior, (2) biplane x-ray images, and (3) the original echo images. Excellent shape and geometry correspondence was observed in both geometries. Quantitative measurements made at key locations of the 3D reconstructions also were in good agreement with those made in silicone moulds. The proposed technique is easily adoptable in clinical practice, since it uses x-rays with minimal exposure and existing IVUS technology. PMID:11105284

  13. Angiopoietin-4 increases permeability of blood vessels and promotes lymphatic dilation.

    PubMed

    Kesler, Cristina T; Pereira, Ethel R; Cui, Cheryl H; Nelson, Gregory M; Masuck, David J; Baish, James W; Padera, Timothy P

    2015-09-01

    The angiopoietin (Ang) ligands are potential therapeutic targets for lymphatic related diseases, which include lymphedema and cancer. Ang-1 and Ang-2 functions are established, but those of Ang-4 are poorly understood. We used intravital fluorescence microscopy to characterize Ang-4 actions on T241 murine fibrosarcoma-associated vessels in mice. The diameters of lymphatic vessels draining Ang-4- or VEGF-C (positive control)-expressing tumors increased to 123 and 135 μm, respectively, and parental, mock-transduced (negative controls) and tumors expressing Ang-1 or Ang-2 remained at baseline (∼60 μm). Ang-4 decreased human dermal lymphatic endothelial cell (LEC) monolayer permeability by 27% while increasing human dermal blood endothelial cell (BEC) monolayer permeability by 200%. In vivo, Ang-4 stimulated a 4.5-fold increase in tumor-associated blood vessel permeability compared with control when measured using intravital quantitative multiphoton microscopy. Ang-4 activated receptor signaling in both LECs and BECs, evidenced by tyrosine kinase with Ig and endothelial growth factor homology domains-2 (TIE2) receptor, protein kinase B, and Erk1,2 phosphorylation detectable by immunoblotting. These data suggest that Ang-4 actions are mediated through cell-type-specific networks and that lymphatic vessel dilation occurs secondarily to increased vascular leakage. Ang-4 also promoted survival of LECs. Thus, blocking Ang-4 may prune the draining lymphatic vasculature and decrease interstitial fluid pressure (IFP) by reducing vascular permeability. PMID:25977256

  14. [The blood vessels of the posterior cranial fossa. anatomy, pathophysiology, clinic--a survey (author's transl)].

    PubMed

    Helms, J

    1978-04-20

    Pathophysiology and tomography of the blood vessels of the posterior cranial fossa gain clinical interest in treatment of diseases of the inner ear, complications of middle ear inflammations, tumors of the pyramid and cerebello-pontine angle. Numerous variations in the arterial venous system restrict neuroradiological procedures. Techniques to treat a thrombosis of the sinuses were developed 50 years ago. Surgical procedures to remove glomus tumors of the pyramid could be improved by new anatomical and surgical experiences. Unilateral neck dissection occasionally alters the blood flow in the sinuses of the posterior cranial fossa causing serious complications. PMID:350206

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  16. Average depth of blood vessels in skin and lesions deduced by optical fiber spectroscopy

    NASA Astrophysics Data System (ADS)

    Jacques, Steven L.; Saidi, Iyad S.; Tittel, Frank K.

    1994-09-01

    The average depth of blood vessels in a cutaneous site, either normal or diseased, can be specified by a simple rapid noninvasive optical measurement. An optical fiber spectrophotometer delivers white light via optical fibers to a skin site. The light reflected by tissue scattering and successfully collected by optical fibers is carried to a diode array spectrophotometer for spectral analysis. The reflectance spectrum is analyzed to specify the component of the optical density (OD) spectrum which is attributed to the cutaneous blood. Then the ratio of the OD420 nm/OD585 nm provides a quantitative indication of the average depth of the blood in the skin site. The purple light (420 nm) less easily penetrates the skin to sample the cutaneous blood content than does the yellow light (585 nm). The calibration of the measurement was accomplished by Monte Carlo simulations of measurements on skin with a layer of blood at various depths. In a study of 47 neonates, the amount of blood content ranged from 4 - 12 mg hemoglobin/g tissue (equivalent to 0.8 - 2.4% of the skin volume being whole blood), and the average depth of blood ranged from 250 - 425 micrometers .

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

    PubMed

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

    2004-01-01

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

  18. Continuous imaging of the blood vessels in tumor mouse dorsal skin window chamber model by using SD-OCT

    NASA Astrophysics Data System (ADS)

    Peng, Xiao; Yang, Shaozhuang; Yu, Bin; Wang, Qi; Lin, Danying; Gao, Jian; Zhang, Peiqi; Ma, Yiqun; Qu, Junle; Niu, Hanben

    2016-03-01

    Optical Coherence Tomography (OCT) has been widely applied into microstructure imaging of tissues or blood vessels with a series of advantages, including non-destructiveness, real-time imaging, high resolution and high sensitivity. In this study, a Spectral Domain OCT (SD-OCT) system with higher sensitivity and signal-to-noise ratio (SNR) was built up, which was used to observe the blood vessel distribution and blood flow in the dorsal skin window chamber of the nude mouse tumor model. In order to obtain comparable data, the distribution images of blood vessels were collected from the same mouse before and after tumor injection. In conclusion, in vivo blood vessel distribution images of the tumor mouse model have been continuously obtained during around two weeks.

  19. Measuring properties of nanoparticles in embryonic blood vessels: Towards a physicochemical basis for nanotoxicity

    NASA Astrophysics Data System (ADS)

    Clancy, Aisling A.; Gregoriou, Yiota; Yaehne, Kristin; Cramb, David T.

    2010-03-01

    The developing field of nanotoxicology aims to relate the physical properties of nanomaterials to potential risk when organisms are exposed to those materials. Regulators are interested in whether a nanoformulation would alter the risk of the native material. It may be that due to the physical nature of embryonic blood vessels (i.e. they are angiogenic and therefore leaky), embryos are at greater risk for bioaccumulation of nanoparticles (NPs) than mature organisms. To study the physicochemical nature of nanoparticle accumulation from embryonic blood vessels, one needs to measure the NP properties in situ, because these properties could be significantly dependent on environment. We have undertaken a study of the dynamics of CdSe/ZnS quantum dots and polystyrene nanospheres in the blood vessels of the chicken embryo chorioallantoic membrane (CAM). We show proof of principle that fluorescence correlation spectroscopy can be used in this system to determine the concentrations and hydrodynamic radii of NP solutions micro-injected into the CAM.

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

    SciTech Connect

    Reinhold, H.S.; Calvo, W.; Hopewell, J.W.; van der Berg, A.P. )

    1990-01-01

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

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

    PubMed

    Donald, John A; Broughton, Brad R S

    2005-10-01

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

  2. Microcirculation-on-a-Chip: A Microfluidic Platform for Assaying Blood- and Lymphatic-Vessel Permeability

    PubMed Central

    Sato, Miwa; Sasaki, Naoki; Ato, Manabu; Hirakawa, Satoshi; Sato, Kiichi; Sato, Kae

    2015-01-01

    We developed a microfluidic model of microcirculation containing both blood and lymphatic vessels for examining vascular permeability. The designed microfluidic device harbors upper and lower channels that are partly aligned and are separated by a porous membrane, and on this membrane, blood vascular endothelial cells (BECs) and lymphatic endothelial cells (LECs) were cocultured back-to-back. At cell-cell junctions of both BECs and LECs, claudin-5 and VE-cadherin were detected. The permeability coefficient measured here was lower than the value reported for isolated mammalian venules. Moreover, our results showed that the flow culture established in the device promoted the formation of endothelial cell-cell junctions, and that treatment with histamine, an inflammation-promoting substance, induced changes in the localization of tight and adherens junction-associated proteins and an increase in vascular permeability in the microdevice. These findings indicated that both BECs and LECs appeared to retain their functions in the microfluidic coculture platform. Using this microcirculation device, the vascular damage induced by habu snake venom was successfully assayed, and the assay time was reduced from 24 h to 30 min. This is the first report of a microcirculation model in which BECs and LECs were cocultured. Because the micromodel includes lymphatic vessels in addition to blood vessels, the model can be used to evaluate both vascular permeability and lymphatic return rate. PMID:26332321

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

    PubMed Central

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

    2012-01-01

    Astrocyte endfeet surround brain blood vessels and can play a role in the delivery of therapeutic drugs for Parkinson's disease. However, there is no previous evidence of the presence of LAT transporter for L-DOPA in brain astrocytes except in culture. Using systemic L-DOPA administration and a combination of patch clamp, histochemistry and confocal microscopy we found that L-DOPA is accumulated mainly in astrocyte cell bodies, astrocytic endfeet surrounding blood vessels, and pericytes. In brain slices: (1) astrocytes were exposed to ASP+, a fluorescent monoamine analog of MPP+; (2) ASP+ taken up by astrocytes was colocalized with L-DOPA fluorescence in (3) glial somata and in the endfeet attached to blood vessels; (4) these astrocytes have an electrogenic transporter current elicited by ASP+, but intriguingly not by L-DOPA, suggesting a different pathway for monoamines and L-DOPA via astrocytic membrane. (5) The pattern of monoamine oxidase (MAO type B) allocation in pericytes and astrocytic endfeet was similar to that of L-DOPA accumulation. We conclude that astrocytes control L-DOPA uptake and metabolism and, therefore, may play a key role in regulating brain dopamine level during dopamine-associated diseases. These data also suggest that different transporter mechanisms may exist for monoamines and L-DOPA. PMID:22888467

  4. Macrophage-Induced Blood Vessels Guide Schwann Cell-Mediated Regeneration of Peripheral Nerves

    PubMed Central

    Cattin, Anne-Laure; Burden, Jemima J.; Van Emmenis, Lucie; Mackenzie, Francesca E.; Hoving, Julian J.A.; Garcia Calavia, Noelia; Guo, Yanping; McLaughlin, Maeve; Rosenberg, Laura H.; Quereda, Victor; Jamecna, Denisa; Napoli, Ilaria; Parrinello, Simona; Enver, Tariq; Ruhrberg, Christiana; Lloyd, Alison C.

    2015-01-01

    Summary The peripheral nervous system has remarkable regenerative capacities in that it can repair a fully cut nerve. This requires Schwann cells to migrate collectively to guide regrowing axons across a ‘bridge’ of new tissue, which forms to reconnect a severed nerve. Here we show that blood vessels direct the migrating cords of Schwann cells. This multicellular process is initiated by hypoxia, selectively sensed by macrophages within the bridge, which via VEGF-A secretion induce a polarized vasculature that relieves the hypoxia. Schwann cells then use the blood vessels as “tracks” to cross the bridge taking regrowing axons with them. Importantly, disrupting the organization of the newly formed blood vessels in vivo, either by inhibiting the angiogenic signal or by re-orienting them, compromises Schwann cell directionality resulting in defective nerve repair. This study provides important insights into how the choreography of multiple cell-types is required for the regeneration of an adult tissue. PMID:26279190

  5. Infrared tomography for diagnostic imaging of port wine stain blood vessels

    SciTech Connect

    Goodman, D.

    1994-11-15

    The objective of this work is the development of Infrared Tomography (IRT) for detecting and characterizing subsurface chromophores in human skin. Characterization of cutaneous chromophores is crucial for advances in the laser treatment of pigmented lesions (e.g., port wine stain birthmarks and tatoos). Infrared tomography (IRT) uses a fast infrared focal plane array (IR-FPA) to detect temperature rises in a substrate induced by pulsed radiation. A pulsed laser is used to produce transient heating of an object. The temperature rise, due to the optical absorption of the pulsed laser light, creates an increase in infrared emission which is measured by the IR-FPA. Although the application of IRT to image subsurface cracks due to metal fatigue is a topic of great interest in the aircraft industry, the application to image subsurface chromophores in biological materials is novel. We present an image recovery method based on a constrained conjugate gradient algorithm that has obtained the first ever high quality images of port wine blood vessels.

  6. Noncoding RNAs regulate NF-κB signaling to modulate blood vessel inflammation

    PubMed Central

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

    2014-01-01

    Cardiovascular diseases such as atherosclerosis are one of the leading causes of morbidity and mortality worldwide. The clinical manifestations of atherosclerosis, which include heart attack and stroke, occur several decades after initiation of the disease and become more severe with age. Inflammation of blood vessels plays a prominent role in atherogenesis. Activation of the endothelium by inflammatory mediators leads to the recruitment of circulating inflammatory cells, which drives atherosclerotic plaque formation and progression. Inflammatory signaling within the endothelium is driven predominantly by the pro-inflammatory transcription factor, NF-κB. Interestingly, activation of NF-κB is enhanced during the normal aging process and this may contribute to the development of cardiovascular disease. Importantly, studies utilizing mouse models of vascular inflammation and atherosclerosis are uncovering a network of noncoding RNAs, particularly microRNAs, which impinge on the NF-κB signaling pathway. Here we summarize the literature regarding the control of vascular inflammation by microRNAs, and provide insight into how these microRNA-based pathways might be harnessed for therapeutic treatment of disease. We also discuss emerging areas of endothelial cell biology, including the involvement of long noncoding RNAs and circulating microRNAs in the control of vascular inflammation. PMID:25540650

  7. Implantable tissue-engineered blood vessels from human induced pluripotent stem cells.

    PubMed

    Gui, Liqiong; Dash, Biraja C; Luo, Jiesi; Qin, Lingfeng; Zhao, Liping; Yamamoto, Kota; Hashimoto, Takuya; Wu, Hongwei; Dardik, Alan; Tellides, George; Niklason, Laura E; Qyang, Yibing

    2016-09-01

    Derivation of functional vascular smooth muscle cells (VSMCs) from human induced pluripotent stem cells (hiPSCs) to generate tissue-engineered blood vessels (TEBVs) holds great potential in treating patients with vascular diseases. Herein, hiPSCs were differentiated into alpha-smooth muscle actin (α-SMA) and calponin-positive VSMCs, which were seeded onto polymer scaffolds in bioreactors for vascular tissue growth. A functional TEBV with abundant collagenous matrix and sound mechanics resulted, which contained cells largely positive for α-SMA and smooth muscle myosin heavy chain (SM-MHC). Moreover, when hiPSC-derived TEBV segments were implanted into nude rats as abdominal aorta interposition grafts, they remained unruptured and patent with active vascular remodeling, and showed no evidence of teratoma formation during a 2-week proof-of-principle study. Our studies represent the development of the first implantable TEBVs based on hiPSCs, and pave the way for developing autologous or allogeneic grafts for clinical use in patients with vascular disease. PMID:27336184

  8. Mapping and vessel-based capabilities

    USGS Publications Warehouse

    Raabe, Ellen A.; Robbins, Lisa L.

    2007-01-01

    U.S. Geological Survey (USGS) scientists from the Florida Integrated Science Center (FISC) conduct scientific investigations of submerged coastal and marine resources using new and existing technologies. Each contributing technique, method, or product adds to our understanding of coastal and marine resources and provides information for resource-management decisionmaking. In support of this mission, the USGS St. Petersburg office maintains a fleet of research vessels used for inland, coastal, and open-water marine surveys and investigations. Each vessel has advantages and limitations related to water depth, carrying capacity, speed, operation in open water, and other functions. These research platforms are staffed by experienced technical and scientific professionals with expertise in marine navigation, geology, geophysics, engineering, biology, and oceanography.

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

    PubMed Central

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

    2009-01-01

    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

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

    PubMed

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

    2015-02-15

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2014-12-01

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

  13. Cooperative phenomena in two-pulse, two-color laser photocoagulation of cutaneous blood vessels.

    PubMed

    Barton, J K; Frangineas, G; Pummer, H; Black, J F

    2001-06-01

    A novel laser system has been developed to study the effects of multiple laser pulses of differing wavelengths on cutaneous blood vessels in vivo, using the hamster dorsal skin flap preparation and in vitro, using cuvettes of whole or diluted blood. The system permits sequenced irradiation with well-defined intrapulse spacing at 532 nm, using a long-pulse frequency-doubled Nd:YAG laser, and at 1064 nm, using a long-pulse Nd:YAG laser. Using this system, we have identified a parameter space where two pulses of different wavelengths act in a synergistic manner to effect permanent vessel damage at radiant exposures where the two pulses individually have little or no effect. Using a two-color pump-probe technique in vitro, we have identified a phenomenon we call greenlight-induced infrared absorption, where a pulse of green light causes photochemical and photothermal modifications to the chemical constituents of blood and results in enhanced infrared absorption. We identify a new chemical species, met-hemoglobin, not normally present in healthy human blood but formed during laser photocoagulation which we believe is implicated in the enhanced near-infrared absorption. PMID:11421070

  14. Spectroscopic imaging of blood vessels only near the skin surface for non-invasive blood glucose measurement

    NASA Astrophysics Data System (ADS)

    Fujiwara, Masaru; Sato, Shun; Abeygunawardhana, Pradeep K. W.; Suzuki, Satoru; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

    2015-07-01

    To realize the non-invasive blood glucose measurement, it will be effective to acquire the spectroscopic imaging of blood vessels only near the skin surface for eliminating other biological-component's disturbances. Our proposed imaging-type 2-dimensional Fourier spectroscopic imaging can limit the measuring depth into focal plane with high light detection sensitivity. Thus, the proposed method will be suitable for measuring only near the skin surface with detecting weak reflected light from inner biomembrane. But reflectance of skin surface is more than 1000 times larger than inner skin's reflectance. Paying attention on Fresnel reflection, fingers what were illuminated by p-polarized beam from Brewster's angle were observed with crossed-Nicol dark field optics. We successfully acquired spectroscopic characteristics of hemoglobin at vein area near the skin surface.

  15. Beam localization in HIFU temperature measurements using thermocouples, with application to cooling by large blood vessels.

    PubMed

    Dasgupta, Subhashish; Banerjee, Rupak K; Hariharan, Prasanna; Myers, Matthew R

    2011-02-01

    Experimental studies of thermal effects in high-intensity focused ultrasound (HIFU) procedures are often performed with the aid of fine wire thermocouples positioned within tissue phantoms. Thermocouple measurements are subject to several types of error which must be accounted for before reliable inferences can be made on the basis of the measurements. Thermocouple artifact due to viscous heating is one source of error. A second is the uncertainty regarding the position of the beam relative to the target location or the thermocouple junction, due to the error in positioning the beam at the junction. This paper presents a method for determining the location of the beam relative to a fixed pair of thermocouples. The localization technique reduces the uncertainty introduced by positioning errors associated with very narrow HIFU beams. The technique is presented in the context of an investigation into the effect of blood flow through large vessels on the efficacy of HIFU procedures targeted near the vessel. Application of the beam localization method allowed conclusions regarding the effects of blood flow to be drawn from previously inconclusive (because of localization uncertainties) data. Comparison of the position-adjusted transient temperature profiles for flow rates of 0 and 400ml/min showed that blood flow can reduce temperature elevations by more than 10%, when the HIFU focus is within a 2mm distance from the vessel wall. At acoustic power levels of 17.3 and 24.8W there is a 20- to 70-fold decrease in thermal dose due to the convective cooling effect of blood flow, implying a shrinkage in lesion size. The beam-localization technique also revealed the level of thermocouple artifact as a function of sonication time, providing investigators with an indication of the quality of thermocouple data for a given exposure time. The maximum artifact was found to be double the measured temperature rise, during initial few seconds of sonication. PMID:20817250

  16. X-ray-induced P-selectin localization to the lumen of tumor blood vessels.

    PubMed

    Hallahan, D E; Staba-Hogan, M J; Virudachalam, S; Kolchinsky, A

    1998-11-15

    P-selectin is a cell adhesion molecule that is sequestered in Weibel-Palade storage reservoirs within the vascular endothelium and alpha granules in platelets. P-selectin is rapidly translocated to the vascular lumen after tissue injury to initiate the adhesion and activation of platelets and leukocytes. We studied the histological pattern of P-selectin expression in irradiated tumor blood vessels. We observed that P-selectin was localized within the endothelium of tumor vessels prior to treatment. At 1-6 h following irradiation, P-selectin was mobilized to the lumen of blood vessels. To determine whether radiation-induced vascular lumen localization of P-selectin was tumor type specific or species specific, we studied tumors in rats, C3H mice, C57BL6 mice, and nude mice. P-selectin localization to the vascular lumen was present in all tumors and all species studied. Irradiated intracranial gliomas showed P-selectin localization to the vascular lumen within 1 h, whereas blood vessels in normal brain showed no P-selectin staining in the endothelium and no localization to the irradiated vascular lumen. Radiation-induced P-selectin localization to the vascular lumen increased in time-dependent manner, until 24 h after irradiation. P-selectin in platelets may account for the time-dependent increase in staining within the vascular lumen after irradiation. We therefore used immunohistochemistry for platelet antigen GP-IIIa to differentiate between endothelial and platelet localization of P-selectin. We found that GP-IIIa staining was not present at 1 h after irradiation, but it increased at 6 and 24 h. P-selectin localization to the vascular lumen at 6-24 h was, in part, associated with platelet aggregation. These findings indicate that radiation-induced P-selectin staining in the vascular lumen of neoplasms is associated with aggregation of platelets. Radiation-induced localization of P-selectin to the vascular lumen is specific to the microvasculature of malignant

  17. A high-affinity human antibody that targets tumoral blood vessels.

    PubMed

    Tarli, L; Balza, E; Viti, F; Borsi, L; Castellani, P; Berndorff, D; Dinkelborg, L; Neri, D; Zardi, L

    1999-07-01

    Angiogenesis is a characteristic feature of many aggressive tumors and of other relevant disorders. Molecules capable of specifically binding to new-forming blood vessels, but not to mature vessels, could be used as selective vehicles and would, therefore, open diagnostic and therapeutic opportunities. We have studied the distribution of the ED-B oncofetal domain of fibronectin, a marker of angiogenesis, in four different tumor animal models: the F9 murine teratocarcinoma, SKMEL-28 human melanoma, N592 human small cell lung carcinoma, and C51 human colon carcinoma. In all of these experimental models we observed accumulation of the fibronectin isoform containing the ED-B domain around neovascular structures when the tumors were in the exponentially growing phase, but not in the slow-growing phase. Then we performed biodistribution studies in mice bearing a subcutaneously implanted F9 murine teratocarcinoma, using a high-affinity human antibody fragment (L19) directed against the ED-B domain of fibronectin. Radiolabeled L19, but not an irrelevant anti-lysozyme antibody fragment (D1.3), efficiently localizes in the tumoral vessels. The maximal dose of L19 accumulated in the tumor was observed 3 hours after injection (8.2% injected dose per gram). By virtue of the rapid clearance of the antibody fragment from the circulation, tumor-to-blood ratios of 1.9, 3.7, and 11.8 were obtained at 3, 5, and 24 hours, respectively. The tumor-targeting performance of L19 was not dose-dependent in the 0.7 to 10 microg range of injected antibody. The integral of the radioactivity localized in tumoral vessels over 24 hours was greater than 70-fold higher than the integral of the radioactivity in blood over the same time period, normalized per gram of tissue or fluid. These findings quantitatively show that new-forming blood vessels can selectively be targeted in vivo using specific antibodies, and suggest that L19 may be of clinical utility for the immunoscintigraphic detection of

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

    PubMed Central

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

    2014-01-01

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

  19. Regulation of cellular communication by signaling microdomains in the blood vessel wall.

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2013-01-01

    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-β1, 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

  1. Application of high-frequency ultrasonography in closing small blood vessels

    PubMed Central

    Malinowska, Sylwia

    2014-01-01

    One of the most common treatments performed in phlebological and aesthetic medicine clinics is closing small blood vessels in the lower extremities, so-called telangiectasias and reticular vessels. Currently, there are several methods that allow for closing the dilated vessels and obtaining desirable effects, both therapeutic and aesthetic. Unfortunately, despite applying various methods and instruments, the effects of treatments are frequently not satisfactory. The factor that largely contributes to decreasing the efficacy of such procedures is complicated anatomy of the venous system and the lack of a method to precisely specify the vessel's course, its diameter, location in the skin etc. High-frequency ultrasonography is a method enabling accurate determination of the vessels’ course as well as the measurement of their basic parameters, such as diameter, depth in the skin and presence or absence of perfusion. Thanks to ultrasound imaging with the use of high-frequency transducers, an adequate treatment method and procedure parameters may be selected, which entails enhancing the efficacy of the procedure itself. Ultrasonography may be also used for monitoring the performed procedures. PMID:26674921

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

    PubMed Central

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

    2009-01-01

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

  3. Drug and light dose responses to focal photodynamic therapy of single blood vessels in vivo

    NASA Astrophysics Data System (ADS)

    Khurana, Mamta; Moriyama, Eduardo H.; Mariampillai, Adrian; Samkoe, Kimberley; Cramb, David; Wilson, Brian C.

    2009-11-01

    As part of an ongoing program to develop two-photon (2-γ) photodynamic therapy (PDT) for treatment of wet-form age-related macular degeneration (AMD) and other vascular pathologies, we have evaluated the reciprocity of drug-light doses in focal-PDT. We targeted individual arteries in a murine window chamber model, using primarily the clinical photosensitizer Visudyne/liposomal-verteporfin. Shortly after administration of the photosensitizer, a small region including an arteriole was selected and irradiated with varying light doses. Targeted and nearby vessels were observed for a maximum of 17 to 25 h to assess vascular shutdown, tapering, and dye leakage/occlusion. For a given end-point metric, there was reciprocity between the drug and light doses, i.e., the response correlated with the drug-light product (DLP). These results provide the first quantification of photosensitizer and light dose relationships for localized irradiation of a single blood vessel and are compared to the DLP required for vessel closure between 1-γ and 2-γ activation, between focal and broad-beam irradiation, and between verteporfin and a porphyrin dimer with high 2-γ cross section. Demonstration of reciprocity over a wide range of DLP is important for further development of focal PDT treatments, such as the targeting of feeder vessels in 2-γ PDT of AMD.

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

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  6. Beta-adrenoceptor-mediated vasodilation of retinal blood vessels is reduced in streptozotocin-induced diabetic rats.

    PubMed

    Nakazawa, Taisuke; Sato, Ayumi; Mori, Asami; Saito, Maki; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2008-01-01

    We investigated the effects of epinephrine and dopamine on retinal blood vessels in streptozotocin (STZ, 80 mg/kg, i.p.)-treated rats and age-matched control rats to determine whether diabetes mellitus alters the retinal vascular responses to circulating catecholamines. Experiments were performed 6-8 weeks after treatment with STZ or the vehicle. The fundus images were captured with the digital fundus camera system for small animals we developed and diameters of retinal blood vessels contained in the digital images were measured. Epinephrine increased the diameters of retinal blood vessels, but the vasodilator responses were reduced in diabetic rats. Dopamine produced a biphasic retinal vascular response with an initial vasoconstriction followed by a vasodilation. The vasoconstrictor effects of dopamine on retinal arterioles were enhanced in diabetic rats, whereas the difference between the two groups was abolished by treatment with propranolol. The vasodilator effect of isoproterenol, but not of the activator of adenylyl cyclase colforsin, on retinal blood vessels was reduced in diabetic rats. No difference in vasoconstriction of retinal blood vessels to phenylephrine between non-diabetic and diabetic rats was observed. The vasodilator responses of retinal blood vessels to 1,1-dimethyl-4-phenylpiperazinium, a ganglionic nicotinic receptor agonist, were also attenuated in diabetic rats. These results suggest that diabetes mellitus alters the retinal vascular responses to circulating catecholamines and the impairment of vasodilator responses mediated by beta-adrenoceptors contributes to the alteration. PMID:18585480

  7. Segmentation of Blood Vessels and 3D Representation of CMR Image

    NASA Astrophysics Data System (ADS)

    Jiji, G. W.

    2013-06-01

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

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

    PubMed

    Truskey, George A; Fernandez, Cristina E

    2015-07-01

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

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

    PubMed

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

    2010-01-01

    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

  10. In Silico Magnetic Nanocontainers Navigation in Blood Vessels: A Feedback Control Approach.

    PubMed

    Do, Ton Duc; Noh, Yeongil; Kim, Myeong Ok; Yoon, Jungwon

    2016-06-01

    Magnetic nanoparticles (MNPs) are recently used in a drug delivery system to pass the blood brain barrier. However, because the magnetic force acting on particles is proportional to their volumes, as the size of particles is small, the large magnetic field is required to produce enough magnetic force for overcoming the hydrodynamic drag force as well as other forces in blood vessels. Other difficulties for controlling MNPs are the complicated behavior of hydrodynamic drag force and uncertain factors in their dynamics. Therefore, open-loop control methods cannot guarantee guiding every MNP to the correct location. Considering these challenges, this paper introduces a feedback control approach for magnetic nanoparticles (MNPs) in blood vessels. To the best of our knowledge, this is the first time feedback controller that is designed for MNPs without aggregation. Simulation studies in MATLAB and real-time verifications on a physical model in COMSOL-MATLAB interface are performed to prove the feasibility of the proposed approach. It is shown that the proposed control scheme can accurately and effectively navigate the MNP to the correct path with feasible hardware supports. PMID:27427720

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

    PubMed Central

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  13. Regional heterogeneity in the reactivity of equine small pulmonary blood vessels.

    PubMed

    Stack, Alice; Derksen, Frederik J; Williams, Kurt J; Robinson, N Edward; Jackson, William F

    2016-03-15

    Regional differences in large equine pulmonary artery reactivity exist. It is not known if this heterogeneity extends into small vessels. The hypothesis that there is regional heterogeneity in small pulmonary artery and vein reactivity to sympathomimetics (phenylephrine and isoproterenol) and a parasympathomimetic (methacholine) was tested using wire myography on small vessels from caudodorsal (CD) and cranioventral (CV) lung of 12 horses [9 mares, 3 geldings, 8.67 ± 0.81 (age ± SE) yr, of various breeds that had never raced]. To study relaxation, vessels were precontracted with U46619 (10(-6) M). Methacholine mechanism of action was investigated using l-nitroarginine methylester (l-NAME, 100 μM) and indomethacin (10 μM). Phenylephrine did not contract any vessels. Isoproterenol relaxed CD arteries more than CV arteries (maximum relaxation 28.18% and 48.67%; Log IC50 ± SE -7.975 ± 0.1327 and -8.033 ± 0.1635 for CD and CV, respectively, P < 0.0001), but not veins. Methacholine caused contraction of CD arteries (maximum contraction 245.4%, Log EC50 ± SE -6.475 ± 0.3341), and relaxation of CV arteries (maximum relaxation 40.14%, Log IC50 ± SE -6.791 ± 0.1954) and all veins (maximum relaxation 50.62%, Log IC50 ± SE -6.932 ± 0.1986) in a nonregion-dependent manner. l-NAME (n = 8, P < 0.0001) and indomethacin (n = 7, P < 0.0001) inhibited methacholine-induced relaxation of CV arteries, whereas indomethacin augmented CD artery contraction (n = 8, P < 0.0001). Our data demonstrate significant regional heterogeneity in small blood vessel reactivity when comparing the CD to the CV region of the equine lung. PMID:26769957

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

    PubMed

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

    2003-05-01

    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

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

    PubMed

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

    1998-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    AS 2 part of the first joint USA-Russian MIR/Shuttle program, fertilized quail eggs were flown on the MIR 18 mission. Post-flight examination indicated impaired survival of both the embryos in space and also of control embryos exposed to vibrational and g-forces simulating the conditions experienced during the launch of Progress 227. We hypothesized that excess mechanical forces and/or other conditions during the launch might cause abnormal development of the blood supply in the chorioallantoic membrane (CAM) leading to the impaired survival of the embryos. The CAM, a highly vascularized extraembryonic organ, provides for the oxygen exchange across the egg shell and is thus pivotal for proper embryonic development. To test our hypothesis, we compared angiogenesis In CAMS of eggs which were either exposed to the vibration and g-force profile simulating the conditions at launch of Progress 227 (synchronous controls), or kept under routine conditions in a laboratory Incubator (laboratory controls). At various time points during Incubation, the eggs were fixed in paraformaldehyde for subsequent dissection. At the time of dissection, the CAM was carefully lifted from the egg shell and examined as whole mounts by bright-field and fluorescent microscopy. The development or the vasculature (angiogenesis) was assessed from the density of blood vessels per viewing field and evaluated by computer aided image analysis. We observed a significant decrease In blood-vessel density in the synchronous controls versus "normal" laboratory controls beginning from day 10 of Incubation. The decrease in vascular density was restricted to the smallest vessels only, suggesting that conditions during the launch and/or during the subsequent Incubation of the eggs may affect the normal progress of angiogenesis in the CAM. Abnormal angiogenesis In the CAM might contribute to the impaired survival of the embryos observed in synchronous controls as well as in space.

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    NASA Technical Reports Server (NTRS)

    Doty, S. B.

    1985-01-01

    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.

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

    SciTech Connect

    Greaby, Robyn; Vaezy, Shahram

    2005-03-28

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

  1. Growing A Living Blood Vessel: insights for the second hundred years

    PubMed Central

    Brewster, Luke P; Bufallino, Dominick; Ucuzian, Areck; Greisler, Howard P

    2007-01-01

    Cardiovascular disease continues to be the leading cause of death worldwide, and the prevelance of cardiovascular disease has reached epidemic proportions worldwide. Not surprisingly this has led to an increasing number of vascular procedures annually. Unfortunately, the success of these procedures over time continues to limit their longterm effects. Biomedical engineering approaches to improve upon current prosthetic grafts, developing new prosthetic grafts, and in creating tissue engineered blood vessels for clinical application offer hope of improving the durability of vascular interventions and improving patients’ treatment for cardiovascular disease. PMID:17706765

  2. Microglia-blood vessel interactions: a double-edged sword in brain pathologies.

    PubMed

    Dudvarski Stankovic, Nevenka; Teodorczyk, Marcin; Ploen, Robert; Zipp, Frauke; Schmidt, Mirko H H

    2016-03-01

    Microglia are long-living resident immune cells of the brain, which secure a stable chemical and physical microenvironment necessary for the proper functioning of the central nervous system (CNS). These highly dynamic cells continuously scan their environment for pathogens and possess the ability to react to damage-induced signals in order to protect the brain. Microglia, together with endothelial cells (ECs), pericytes and astrocytes, form the functional blood-brain barrier (BBB), a specialized endothelial structure that selectively separates the sensitive brain parenchyma from blood circulation. Microglia are in bidirectional and permanent communication with ECs and their perivascular localization enables them to survey the influx of blood-borne components into the CNS. Furthermore, they may stimulate the opening of the BBB, extravasation of leukocytes and angiogenesis. However, microglia functioning requires tight control as their dysregulation is implicated in the initiation and progression of numerous neurological diseases. Disruption of the BBB, changes in blood flow, introduction of pathogens in the sensitive CNS niche, insufficient nutrient supply, and abnormal secretion of cytokines or expression of endothelial receptors are reported to prime and attract microglia. Such reactive microglia have been reported to even escalate the damage of the brain parenchyma as is the case in ischemic injuries, brain tumors, multiple sclerosis, Alzheimer's and Parkinson's disease. In this review, we present the current state of the art of the causes and mechanisms of pathological interactions between microglia and blood vessels and explore the possibilities of targeting those dysfunctional interactions for the development of future therapeutics. PMID:26711460

  3. Effects of a protein glycocalyx in the hemodynamics of small blood vessels

    NASA Astrophysics Data System (ADS)

    Dimakopoulos, Yiannis; Delidakis, George; Tsamopoulos, John

    2015-11-01

    Glycocalyx is a protein layer of approximate thickness 0.5 μm that lines vessel walls. We study the effects this layer has on the blood flow inside arterioles and venules, where the relative size of the glycocalyx is significant. To properly describe phenomena that naturally occur in blood flow, such as the inhomogeneous distribution of red blood cells and their aggregation, we use an improved viscoelastic constitutive model. The glycocalyx layer is modeled as fixed porous media. Cells cannot penetrate inside it, since its hydraulic permeability is very low, and the flow inside this layer is described by the equations for a viscous fluid with an extra Brinkman term to account for the effects the porous medium has on the flow. The closed set of equations is solved using the Finite Element method, assuming steady-state with dependence only in the r-direction. Our results are favorably compared with the in vivo velocity profiles in venules of mice produced by Damiano et al. (2004) and the formation of cell-free layer near glycocalyx. Flow inside the glycocalyx layer is found to be severely attenuated due to the low hydraulic permeability, which can have interesting implications in the transport of various substances form the blood to the tissues or in the use of shear stresses as signals for the endothelial surface cells. Finally, we simulate the transient blood flow under pulsatile conditions.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-01-01

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

  6. Blood compatibility of artificial blood vessels probed by infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Steiner, Gerald; Maitz, Manfred; Tunc, Sibel; Salzer, Reiner

    2006-02-01

    The determination of protein structure and function plays an important role in biomedical and biochemical research. Common techniques that give full structural information do not permit in-vivo measurements. Infrared spectroscopy has a sufficient sensitivity to examine the structure of proteins solution under in-situ conditions and even on surfaces. However, measurements at few spots on the surface are not suitable to find out the blood compatibility of the protein layer, because the changes in conformation occur often in small domains. Here we report on the investigations of adsorbed fibrinogen with FTIR imaging. FTIR imaging permits an identification of coagulation spots in the micrometer range and the identification of coagulation spots on the implant material.

  7. Hydrodynamic modeling of targeted magnetic-particle delivery in a blood vessel.

    PubMed

    Weng, Huei Chu

    2013-03-01

    Since the flow of a magnetic fluid could easily be influenced by an external magnetic field, its hydrodynamic modeling promises to be useful for magnetically controllable delivery systems. It is desirable to understand the flow fields and characteristics before targeted magnetic particles arrive at their destination. In this study, we perform an analysis for the effects of particles and a magnetic field on biomedical magnetic fluid flow to study the targeted magnetic-particle delivery in a blood vessel. The fully developed solutions of velocity, flow rate, and flow drag are derived analytically and presented for blood with magnetite nanoparticles at body temperature. Results reveal that in the presence of magnetic nanoparticles, a minimum magnetic field gradient (yield gradient) is required to initiate the delivery. A magnetic driving force leads to the increase in velocity and has enhancing effects on flow rate and flow drag. Such a magnetic driving effect can be magnified by increasing the particle volume fraction. PMID:24231820

  8. The role of prostanoids and nitric oxide in endotoxin-induced hyporesponsiveness of equine digital blood vessels.

    PubMed

    Bailey, S R; Elliott, J

    1999-05-01

    Endotoxin has been implicated in the pathophysiology of acute laminitis. The aim of this study was to examine the direct effects of endotoxin on isolated equine digital blood vessels. Equine digital veins (EDV), incubated in Krebs-Henseleit solution containing lipopolysaccharide (LPS) (1 microg/ml) became hyporesponsive to 5-HT after 16 h. Cycloheximide and ibuprofen blocked this effect of LPS and increased the maximum response obtained to 5-HT when compared to control vessels. L-nitroarginine methyl ester (L-NAME) reversed the hyporesponsiveness caused by LPS. Vessels maintained in culture medium containing LPS also became hyporesponsive to 5-HT, an effect which was completely prevented by ibuprofen but only partially reversed by L-NAME. Measurements were made of 6-keto PGF1alpha and nitrite production by segments of equine digital artery and vein in culture medium alone or co-cultured with peripheral blood leucocytes. LPS did not stimulate nitrite production from vessel segments but increased nitrite release from leucocytes, an effect which was inhibited by cycloheximide and L-NAME. Lipopolysaccharide increased 6-keto PGF1alpha production by blood vessels, an effect which was inhibited by cycloheximide and ibuprofen but not L-NAME. No synergistic effect on release of nitrite or 6-keto PGF1alpha was noted in co-cultures of blood vessels and leucocytes. These data suggest that induction of cyclo-oxygenase by LPS was a major cause of hyporesponsiveness of digital blood vessels to 5-HT. Release of nitric oxide was not detectable in LPS-stimulated blood vessels maintained in culture even in the presence of activated leucocytes yet L-NAME did protect against LPS-induced hyporesponsiveness indicating nitric oxide synthase induction may play some role in the effect of LPS. These findings are important in furthering our understanding of the pathophysiological mechanisms underlying the vascular changes which occur in acute laminitis. PMID:10402134

  9. An Ultrasound Simulation Model for the Pulsatile Blood Flow Modulated by the Motion of Stenosed Vessel Wall

    PubMed Central

    Zhou, Yi; Zhang, Kun; Zhang, Kexin; Gao, Lian

    2016-01-01

    This paper presents an ultrasound simulation model for pulsatile blood flow, modulated by the motion of a stenosed vessel wall. It aims at generating more realistic ultrasonic signals to provide an environment for evaluating ultrasound signal processing and imaging and a framework for investigating the behaviors of blood flow field modulated by wall motion. This model takes into account fluid-structure interaction, blood pulsatility, stenosis of the vessel, and arterial wall movement caused by surrounding tissue's motion. The axial and radial velocity distributions of blood and the displacement of vessel wall are calculated by solving coupled Navier-Stokes and wall equations. With these obtained values, we made several different phantoms by treating blood and the vessel wall as a group of point scatterers. Then, ultrasound echoed signals from oscillating wall and blood in the axisymmetric stenotic-carotid arteries were computed by ultrasound simulation software, Field II. The results show better consistency with corresponding theoretical values and clinical data and reflect the influence of wall movement on the flow field. It can serve as an effective tool not only for investigating the behavior of blood flow field modulated by wall motion but also for quantitative or qualitative evaluation of new ultrasound imaging technology and estimation method of blood velocity. PMID:27478840

  10. An Ultrasound Simulation Model for the Pulsatile Blood Flow Modulated by the Motion of Stenosed Vessel Wall.

    PubMed

    Zhang, Qinghui; Zhang, Yufeng; Zhou, Yi; Zhang, Kun; Zhang, Kexin; Gao, Lian

    2016-01-01

    This paper presents an ultrasound simulation model for pulsatile blood flow, modulated by the motion of a stenosed vessel wall. It aims at generating more realistic ultrasonic signals to provide an environment for evaluating ultrasound signal processing and imaging and a framework for investigating the behaviors of blood flow field modulated by wall motion. This model takes into account fluid-structure interaction, blood pulsatility, stenosis of the vessel, and arterial wall movement caused by surrounding tissue's motion. The axial and radial velocity distributions of blood and the displacement of vessel wall are calculated by solving coupled Navier-Stokes and wall equations. With these obtained values, we made several different phantoms by treating blood and the vessel wall as a group of point scatterers. Then, ultrasound echoed signals from oscillating wall and blood in the axisymmetric stenotic-carotid arteries were computed by ultrasound simulation software, Field II. The results show better consistency with corresponding theoretical values and clinical data and reflect the influence of wall movement on the flow field. It can serve as an effective tool not only for investigating the behavior of blood flow field modulated by wall motion but also for quantitative or qualitative evaluation of new ultrasound imaging technology and estimation method of blood velocity. PMID:27478840

  11. Analysis of nitric oxide consumption by erythrocytes in blood vessels using a distributed multicellular model.

    PubMed

    El-Farra, Nael H; Christofides, Panagiotis D; Liao, James C

    2003-03-01

    Multiple sets of experimental data have shown that the red blood cell (RBC) consumes nitric oxide (NO) about 600-1000-fold slower than the equivalent concentration of cell-free hemoglobin (Hb). Diffusion barriers of various sources have been suggested to explain this observation. In this work, a multicellular, spatially distributed, two-dimensional model, that describes the production, transport, and consumption of NO in blood vessels and the surrounding tissue, is developed. The model is used to assess the relative significance of NO transport barriers that reduce the rate of NO consumption in the blood. Unlike previous models of this system, the model developed here accounts explicitly for the presence of, and interactions among, a population of RBCs inside the lumen of the blood vessel and is, therefore, better suited to analyze, quantitatively, the contribution of each transport barrier as NO diffuses from its site of synthesis to the interior of the RBCs where it interacts with Hb. The model, which uses experimentally derived parameters, shows that extracellular unstirred boundary layer diffusion alone cannot account for the reduced NO consumption by RBC compared to an equivalent concentration of cell-free Hb. Since this result is reached using a two-dimensional representation of the RBCs, which overestimates the importance of the boundary layer diffusion resistance, it would be expected that in the real three-dimensional case, diffusion through the extracellular boundary layer would contribute even less to the overall mass transfer resistance. Consistent with recent experimental findings, the results of our model suggest that, under physiological conditions, transmembrane (membrane and its associated cytoskeleton layer) diffusion limitations in RBCs represent a key source of resistance for NO uptake by RBCs. PMID:12680727

  12. Synchronization of endothelial Dll4-Notch dynamics switch blood vessels from branching to expansion

    PubMed Central

    Ubezio, Benedetta; Blanco, Raquel Agudo; Geudens, Ilse; Stanchi, Fabio; Mathivet, Thomas; Jones, Martin L; Ragab, Anan; Bentley, Katie; Gerhardt, Holger

    2016-01-01

    Formation of a regularly branched blood vessel network is crucial in development and physiology. Here we show that the expression of the Notch ligand Dll4 fluctuates in individual endothelial cells within sprouting vessels in the mouse retina in vivo and in correlation with dynamic cell movement in mouse embryonic stem cell-derived sprouting assays. We also find that sprout elongation and branching associates with a highly differential phase pattern of Dll4 between endothelial cells. Stimulation with pathologically high levels of Vegf, or overexpression of Dll4, leads to Notch dependent synchronization of Dll4 fluctuations within clusters, both in vitro and in vivo. Our results demonstrate that the Vegf-Dll4/Notch feedback system normally operates to generate heterogeneity between endothelial cells driving branching, whilst synchronization drives vessel expansion. We propose that this sensitive phase transition in the behaviour of the Vegf-Dll4/Notch feedback loop underlies the morphogen function of Vegfa in vascular patterning. DOI: http://dx.doi.org/10.7554/eLife.12167.001 PMID:27074663

  13. Experimental analysis of blood vessel development in the avian wing bud.

    PubMed

    Feinberg, R N; Noden, D M

    1991-09-01

    Shortly after its appearance, the avian limb bud becomes populated by a rich plexus of vascular channels. Formation of this plexus occurs by angiogenesis, specifically the ingrowth of branches from the dorsal aorta or cardinal veins, and by differentiation of endogenous angioblasts within limb mesoderm. However, mesenchyme located immediately beneath the surface ectoderm of the limb is devoid of patent blood vessels. The objective of this research is to ascertain whether peripheral limb mesoderm lacks angioblasts at all stages or becomes avascular secondarily during limb development. Grafts of core or peripheral wing mesoderm, identified by the presence or absence of patent channels following systemic infusion with ink, were grafted from quail embryos at stages 16-26 into the head region of chick embryos at stages 9-10. Hosts were fixed 3-5 days later and sections treated with antibodies that recognize quail endothelial cells and their precursors. Labeled endothelial cells were found intercalated into normal craniofacial blood vessels both nearby and distant from the site of implantation following grafting of limb core mesoderm from any stage. Identical results were obtained following grafting of limb peripheral mesoderm at stages 16-21. However, peripheral mesoderm from donors older than stage 22 did not contain endothelial precursors. Thus at the onset of appendicular development angioblasts are present throughout the mesoderm of the limb bud. During the fourth day of incubation, these cells are lost from peripheral mesoderm, either through emigration or degeneration. PMID:1750708

  14. Mycobacterium tuberculosis exploits the formation of new blood vessels for its dissemination.

    PubMed

    Polena, Helena; Boudou, Frédéric; Tilleul, Sylvain; Dubois-Colas, Nicolas; Lecointe, Cécile; Rakotosamimanana, Niaina; Pelizzola, Mattia; Andriamandimby, Soa Fy; Raharimanga, Vaomalala; Charles, Patricia; Herrmann, Jean-Louis; Ricciardi-Castagnoli, Paola; Rasolofo, Voahangy; Gicquel, Brigitte; Tailleux, Ludovic

    2016-01-01

    The mechanisms by which the airborne pathogen Mycobacterium tuberculosis spreads within the lung and leaves its primary niche to colonize other organs, thus inducing extrapulmonary forms of tuberculosis (TB) in humans, remains poorly understood. Herein, we used a transcriptomic approach to investigate the host cell gene expression profile in M. tuberculosis-infected human macrophages (ΜΦ). We identified 33 genes, encoding proteins involved in angiogenesis, for which the expression was significantly modified during infection, and we show that the potent angiogenic factor VEGF is secreted by M. tuberculosis-infected ΜΦ, in an RD1-dependent manner. In vivo these factors promote the formation of blood vessels in murine models of the disease. Inhibiting angiogenesis, via VEGF inactivation, abolished mycobacterial spread from the infection site. In accordance with our in vitro and in vivo results, we show that the level of VEGF in TB patients is elevated and that endothelial progenitor cells are mobilized from the bone marrow. These results strongly strengthen the most recent data suggesting that mycobacteria take advantage of the formation of new blood vessels to disseminate. PMID:27616470

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

    PubMed

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

    2014-01-01

    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

  16. Differential lectin binding on walls of thoraco-cervical blood vessels and lymphatics in rats.

    PubMed

    Kagami, H; Uryu, K; Okamoto, K; Sakai, H; Kaneda, T; Sakanaka, M

    1991-08-01

    Lectin binding in the walls of large to medium-sized blood vessels and lymphatics in the rat thoraco-cervical region was examined histochemically. The tunica intima of the aorta and superficial cervical artery showed positive reactions with wheat germ agglutinin (WGA) and Concanavalin A (ConA) but not with Dolichus biflorus agglutinin (DBA). The tunica media of the aorta exhibited intense WGA binding, especially on the smooth muscle cells, but the tunica media of the superficial cervical artery did not react with the lectin. Neither ConA nor DBA bound to the tunica media of the aorta and superficial cervical artery. The tunica adventitia of both arteries contained sites binding the three lectins, although DBA reactivity declined as the vascular diameter decreased. The tunica intima of the superior vena cava and azygos vein exhibited positive WGA and ConA binding, whereas DBA binding was noted on only part of the tunica intima of the superior vena cava and not on that of the azygos vein. The tunica media and tunica adventitia were reactive for all three lectins. The WGA and ConA binding sites in the tunica adventitia showed loose networks, suggesting lectin binding on connective tissue elements interlacing among smooth muscle bundles. Lectin binding sites in the walls of lymphatics exhibited an arrangement similar to those in the walls of the veins. Moreover valves protruding into the lumen showed intense WGA and ConA binding and scattered DBA binding. Three other lectins (Ulex europaeus agglutinin, peanut agglutinin, Maclura pomifera) were examined, but they showed no reactions with the vessels. Thus, the differential binding of lectins on the walls of blood vessels and lymphatics of various sizes suggests the functional complexity of monosaccharide residues in the vascular walls. PMID:1758681

  17. Patency of heart blood vessels under photosensitization reaction shortly after intravenous injection of talaporfin sodium in canine model

    NASA Astrophysics Data System (ADS)

    Hamada, Risa; Matsuzaki, Ryota; Ogawa, Emiyu; Arai, Tsunenori

    2016-03-01

    In order to investigate patency of heart blood vessels by photosensitization reaction shortly after intravenous injection of talaporfin sodium, we performed in vitro endothelial cell lethality study and in vivo study of heart blood vessel patency in canine one week after photosensitization reaction. Cell lethality of human umbilical vein endothelial cells under different albumin concentrations corresponding with blood and interstice concentrations were employed and their lethality 2 hours after the reaction was measured by WST assay in vitro. Almost all cells survived by 40 J/cm2 photosensitization reaction with blood albumin concentration. Laser diffuser made of plastic optical fiber with 70 mm in length was used in vivo. Red diode laser of 664nm wavelength was emitted from this diffuser with 17.1-42.9 mW/cm in 10 minutes. We estimated the fluence rate distribution by a ray-trace simulator using pre-measured optical coefficients of myocardium tissue, μa 0.12 mm-1 and μs' 0.36 mm-1. Almost all blood vessels were patent in every irradiation conditions in canine heart. Coronary artery and vein up to 1 mm diameter were patent in typical myocardium sample with 25.7 mW/cm. We estimated fluence rate distribution of this sample and found that blood vessels were patent even fluence rate over 40 J/cm2. This in vivo study could be explained by the result of in vitro study. We suggest that this blood vessel patency after our particular photosensitization reaction might be because of few photosensitizer uptake in the blood endothelial cells and/or reduced oxidation damage by thick albumin concentration in blood.

  18. Pharmacological evidence for the presence of functional beta(3)-adrenoceptors in rat retinal blood vessels.

    PubMed

    Mori, Asami; Miwa, Tomoyo; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2010-08-01

    The aim of this study was to examine whether stimulation of beta(3)-adrenoceptors dilates rat retinal blood vessels and how diabetes affects the vasodilator responses. Images of ocular fundus were captured with an original high-resolution digital fundus camera in vivo. The retinal vascular responses were evaluated by measuring diameter of retinal blood vessels contained in the digital images. Both systemic blood pressure and heart rate (HR) were continuously recorded. The beta(3)-adrenoceptor agonist CL316243 (0.3-10 microg/kg/min, i.v.) increased diameter of retinal arterioles (at 10 microg/kg/min, a 31% increase) and decreased mean blood pressure (at 10 microg/kg/min, a 21% decrease) in a dose-dependent manner. CL316243 produced a small but significant increase in HR (at 10 microg/kg/min, a 9% increase). Both SR59230A (1 mg/kg, i.v.) and L-748337 (50 microg/kg, i.v.), beta(3)-adrenoceptor antagonists, significantly prevented CL316243-induced retinal vasodilator responses. Similar observations were made with another beta(3)-adrenoceptor agonist, BRL37344. The beta(2)-adrenoceptor agonist salbutamol also increased diameter of retinal arterioles (at 10 microg/kg/min, a 43% increase), whereas the drug produced greater decrease in blood pressure (at 10 microg/kg/min, a 46% decrease) and increase in HR (at 10 microg/kg/min, a 16% increase), compared with beta(3)-adrenoceptor agonists. The retinal vasodilator responses to CL316243 and BRL37344 observed under blockade of beta(1)/beta(2)-adrenoceptors with propranolol (2 mg/kg, i.v. bolus followed by 100 microg/kg/min infusion) were unaffected 2 weeks after induction of diabetes by the combination of streptozotocin treatment and D: -glucose feeding. On the other hand, the vasodilator responses to salbutamol of retinal arterioles were significantly reduced in diabetic rats. These results suggest that stimulation of beta(3)-adrenoceptors causes the vasodilation of retinal arterioles in vivo and the vasodilator responses are

  19. Quantitative investigations of the adhesiveness of circulating polymorphonuclear leucocytes to blood vessel walls

    PubMed Central

    Atherton, Anne; Born, G. V. R.

    1972-01-01

    1. A new simple method is described for quantitating the adhesiveness of circulating polymorphonuclear leucocytes, or granulocytes, to the walls of blood vessels. The cheek pouch of anaesthetized hamsters or a small part of the mesentery of anaesthetized mice were prepared for continuous microscopic observation of selected venules. Those granulocytes which moved sufficiently slowly to be individually visible were counted for 1 or 2 min periods as they rolled past a selected point on one side of a vessel. The velocity distribution of these cells was determined by analysing films. Films were used also to measure mean blood flow velocity in the venules by observing embolizing platelet thrombi induced by the iontophoretic application of adenosine diphosphate. Emigration of granulocytes into the tissues was quantitated by enumerating them in standard areas of stained histological sections. 2. In control experiments with hamster cheek pouch venules, the rolling granulocyte count usually passed through a maximum shortly after the preparation was set up and then fell to a low constant value. In mouse mesentery venules the count remained at a low approximately constant value from the beginning for at least 3 hr. 3. The mean velocity of blood flow in the venules was between 900 and 200 μ/sec. All rolling granulocytes moved much more slowly; in hamster cheek pouch venules the mean velocity was about 20 μ/sec and in mouse mesentery venules about 10 μ/sec. Around these means the velocity distribution of individual cells was narrow. 4. Rolling of granulocytes was abolished by superfusing ethylenediamine tetra-acetate (EDTA, 0·1 M) suggesting that the phenomenon depends on calcium or magnesium ions. 5. Agents were applied locally to the observed venules. Human serum albumin, trypsin or histamine in high concentrations did not affect the rolling granulocyte count. 6. The rolling granulocyte count was increased during the application of Hammarsten casein or Escherichia coli

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

    NASA Technical Reports Server (NTRS)

    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

    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).

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

    SciTech Connect

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

    2013-11-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) 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 (−)-α-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 (−)-α-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 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  2. 3-D trajectory model for MDT using micro-spheres implanted within large blood vessels

    NASA Astrophysics Data System (ADS)

    Choomphon-anomakhun, Natthaphon; Natenapit, Mayuree

    2016-09-01

    Implant assisted magnetic drug targeting (IA-MDT) using ferromagnetic spherical targets implanted within large blood vessels and subjected to a uniform externally applied magnetic field (H0) has been investigated and reported for the first time. The capture areas (As) of magnetic drug carrier particles (MDCPs) were determined from the analysis of particle trajectories simulated from equations of motion. Then, the effects of various parameters, such as types of ferromagnetic materials in the targets and MDCPs, blood flow rates, mass fraction of the ferromagnetic material in the MDCPs, average radii of MDCPs (Rp) and the strength of H0 on the As were obtained. Furthermore, the effects of saturation magnetization of the ferromagnetic materials in the MDCPs and within the targets on the As were analyzed. After this, the suitable strengths of H0 and Rp for IA-MDT designs were reported. Dimensionless As, ranging from 2 to 7, was obtained with Rp ranging from 500 to 2500 nm, μ0H0 less than 0.8 T and a blood flow rate of 0.1 m s-1. The target-MDCP materials considered are iron-iron, iron-magnetite and SS409-magnetite, respectively.

  3. Responses of bone and joint blood vessels in cats and rabbits to electrical stimulation of nerves supplying the knee.

    PubMed Central

    Ferrell, W R; Khoshbaten, A; Angerson, W J

    1990-01-01

    1. Experiments were performed to assess the extent to which knee joint blood flow in cats and rabbits is affected by electrical stimulation of the nerve supply to the knee. 2. Absolute changes in blood flow were measured using the radiolabelled microsphere (approximately 15 microns) technique whilst relative changes in blood flow were assessed using laser Doppler flowmetry. 3. Despite deep general anaesthesia, sympathetic nerve fibres innervating cat knee joint blood vessels showed marked 'tone'. 4. Blood flow to the joint capsule (synovium and overlying fibrous and areolar tissues) was substantially reduced (by approximately 90% in the cat and approximately 45% in the rabbit) during electrical stimulation of the articular nerve supply. 5. The percentage change in the laser Doppler flowmeter signal did not differ significantly from the percentage change in blood flow measured by microsphere technique. 6. Blood vessels in the cancellous bone of the distal femur (condyles) and proximal tibia (plateau) appear to be innervated by vasoconstrictor fibres which reach their effectors via the articular nerves. However, the cortical bone and red marrow of the diaphysis of the femur do not receive such innervation. 7. The potency of the vasoconstrictor influences acting on joint blood vessels could be of relevance in the pathogenesis of inflammatory joint diseases. PMID:2100317

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    SciTech Connect

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

    2007-08-01

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

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

    PubMed

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

    2015-06-01

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

  8. Wrong theories on the origin of blood vessels: Polybus and De Natura Hominis.

    PubMed

    Shoja, Mohammadali M; Tubbs, R Shane; Loukas, Marios; Ardalan, Mohammad R

    2008-06-01

    Polybus of Cos (approximately 400 B.C.) was the son-in-law and the successor of Hippocrates. He is credited with founding the school of Dogmatism, and writing "The Nature of Man" which was important in advancing the theory of the four body humors (humoralism). Some earlier scholars negated Polybus' role as an independent medical figure. However, Corpus Aristotelicum quoted him as having a unique theory regarding the body vasculature which stated that this system was composed of four pairs of blood vessels originating from the head and that these supplied the whole body. In an interpretation of this theory, we opined that numerological mysticism might have been the common motive for both Hippocrates' humoralism and Polybus' theory of the vasculature. A discussion on this issue is presented. PMID:18164081

  9. Cathodic-controlled and near-infrared organic upconverter for local blood vessels mapping

    PubMed Central

    Yuan, Chih-Hsien; Lee, Chih-Chien; Liu, Chun-Fu; Lin, Yun-Hsuan; Su, Wei-Cheng; Lin, Shao-Yu; Chen, Kuan-Ting; Li, Yan-De; Chang, Wen-Chang; Li, Ya-Ze; Su, Tsung-Hao; Liu, Yu-Hsuan; Liu, Shun-Wei

    2016-01-01

    Organic materials are used in novel optoelectronic devices because of the ease and high compatibility of their fabrication processes. Here, we demonstrate a low-driving-voltage cathodic-controlled organic upconverter with a mapping application that converts near-infrared images to produce images of visible blood vessels. The proposed upconverter has a multilayer structure consisting of a photosensitive charge-generation layer (CGL) and a phosphorescent organic light-emitting diode (OLED) for producing clear images with a high resolution of 600 dots per inch. In this study, temperature-dependent electrical characterization was performed to analyze the interfacial modification of the cathodic-controlled upconverter. The result shows that the upconverter demonstrated a high conversion efficiency of 3.46% because of reduction in the injection barrier height at the interface between the CGL and the OLED. PMID:27578199

  10. Vascular tissue engineering of small-diameter blood vessels: reviewing the electrospinning approach.

    PubMed

    Ercolani, Enrico; Del Gaudio, Costantino; Bianco, Alessandra

    2015-08-01

    Vascular tissue engineering is a relevant research field aimed at elaborating and proposing innovative solutions to overcome the drawbacks related to the use of conventional blood vessel substitutes, especially referring to small-diameter grafts. For this aim, electrospinning can be regarded as a valuable technique to produce novel scaffolds with several functional characteristics that can be usefully tailored for the application discussed here. The reproduction of the natural extracellular matrix obtained by processing bioresorbable polymers, either functionalized or not, is driving the biomedical research towards technical solutions that can lead to an actual therapeutic improvement. In this context, this paper reviews those studies focused on the selection of suitable biomaterials for vascular applications, their microstructure, the cell response to polymeric fibres and the strategies considered so far to modify and therefore enhance the performance of final electrospun scaffolds. PMID:23365048

  11. Cathodic-controlled and near-infrared organic upconverter for local blood vessels mapping.

    PubMed

    Yuan, Chih-Hsien; Lee, Chih-Chien; Liu, Chun-Fu; Lin, Yun-Hsuan; Su, Wei-Cheng; Lin, Shao-Yu; Chen, Kuan-Ting; Li, Yan-De; Chang, Wen-Chang; Li, Ya-Ze; Su, Tsung-Hao; Liu, Yu-Hsuan; Liu, Shun-Wei

    2016-01-01

    Organic materials are used in novel optoelectronic devices because of the ease and high compatibility of their fabrication processes. Here, we demonstrate a low-driving-voltage cathodic-controlled organic upconverter with a mapping application that converts near-infrared images to produce images of visible blood vessels. The proposed upconverter has a multilayer structure consisting of a photosensitive charge-generation layer (CGL) and a phosphorescent organic light-emitting diode (OLED) for producing clear images with a high resolution of 600 dots per inch. In this study, temperature-dependent electrical characterization was performed to analyze the interfacial modification of the cathodic-controlled upconverter. The result shows that the upconverter demonstrated a high conversion efficiency of 3.46% because of reduction in the injection barrier height at the interface between the CGL and the OLED. PMID:27578199

  12. Radiation-guided drug delivery to tumor blood vessels results in improved tumor growth delay.

    PubMed

    Geng, Ling; Osusky, Katherine; Konjeti, Sekhar; Fu, Allie; Hallahan, Dennis

    2004-10-19

    Tumor blood vessels are biological targets for cancer therapy. In this study, a tumor vasculature targeting system that consisted of liposomes and lectin (WGA) was built. Liposomes were used to carry a number of liposome-friendly anti-tumoral agents along with WGA, a lectin which posseses a specific affinity for binding to inflamed endothelial cells. In order to target tumor vasculature, inflammation of endothelial cells was induced by radiation. Because ionizing radiation induces an inflammatory response in tumor vasculature, lectin-conjugates were utilized to determine whether radiation can be used to target drug delivery to tumor vessels. Wheat germ agglutinin (WGA) is one such lectin that binds to inflamed microvasculature. WGA was conjugated to liposomes containing cisplatin and administered to tumor bearing mice. Tumor growth delay was used to analyze the efficacy of cytotoxicity. FITC-conjugated WGA accumulated within irradiated tumor microvasculature. WGA was conjugated to liposomes and labeled with 111In. This demonstrated radiation-inducible tumor-selective binding. WGA-liposome-conjugates were loaded with Cisplatin and administered to mice bearing irradiated tumors. Tumors treated with a combination of liposome encapsulated cisplatin together with radiation showed a significant increase in tumor growth delay as compared to radiation alone. These findings demonstrate that ionizing radiation can be used to guide drug delivery to tumor microvasculature. PMID:15451595

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

    PubMed

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

    2015-09-01

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

  14. Angiogenin expression during early human placental development; association with blood vessel formation.

    PubMed

    Pavlov, Nadine; Frendo, Jean-Louis; Guibourdenche, Jean; Degrelle, Séverine A; Evain-Brion, Danièle; Badet, Josette

    2014-01-01

    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

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

    PubMed

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

    2011-11-22

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-04-01

    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.

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

    PubMed Central

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

    2015-01-01

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

  18. Electrospun Polycaprolactone Scaffolds for Small-Diameter Tissue Engineered Blood Vessels

    NASA Astrophysics Data System (ADS)

    Lee, Carol Hsiu-Yueh

    Cardiovascular disease is the leading cause of death in the United States with many patients requiring coronary artery bypass grafting. The current standard is using autografts such as the saphenous vein or intimal mammary artery, however creating a synthetic graft could eliminate this painful and inconvenient procedure. Large diameter grafts have long been established with materials such as DacronRTM and TeflonRTM, however these materials have not proved successful in small-diameter (< 6 mm) grafts where thrombosis and intimal hyperplasia are common in graft failure. With the use of a synthetic biodegradable polymer (polycaprolactone) we utilize our expertise in electrospinning and femtosecond laser ablation to create a novel tri-layered tissue engineered blood vessel containing microchannels. The benefits of creating a tri-layer is to mimic native arteries that contain an endothelium to prevent thrombosis in the inner layer, aligned smooth muscle cells in the middle to control vasodilation and constriction, and a mechanically robust outer layer. The following work evaluates the mechanical properties of such a graft (tensile, fatigue, burst pressure, and suture retention strength), the ability to rapidly align cells in laser ablated microchannels in PCL scaffolds, and the biological integration (co-culture of endothelial and smooth muscle cells) with electrospun PCL scaffolds. The conclusions from this work establish that the electrospun tri-layers provide adequate mechanical strength as a tissue engineered blood vessel, that laser ablated microchannels are able to contain the smooth muscle cells, and that cells are able to adhere to PCL fibers. However, future work includes adjusting microchannel dimensions to properly align smooth muscle cells along with perfect co-cultures of endothelial and smooth muscle cells on the electrospun tri-layer.

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

    PubMed

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

    2013-11-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (-)-α-bisabolol, farnesene, umbelliferone; 3-30 μM) 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 (-)-α-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 (-)-α-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 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (-)-α-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

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

    PubMed

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

    2013-06-01

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

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

    SciTech Connect

    D. W. Nigg

    2012-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  3. Mathematical Modelling of a Brain Tumour Initiation and Early Development: A Coupled Model of Glioblastoma Growth, Pre-Existing Vessel Co-Option, Angiogenesis and Blood Perfusion

    PubMed Central

    Cai, Yan; Wu, Jie; Li, Zhiyong; Long, Quan

    2016-01-01

    We propose a coupled mathematical modelling system to investigate glioblastoma growth in response to dynamic changes in chemical and haemodynamic microenvironments caused by pre-existing vessel co-option, remodelling, collapse and angiogenesis. A typical tree-like architecture network with different orders for vessel diameter is designed to model pre-existing vasculature in host tissue. The chemical substances including oxygen, vascular endothelial growth factor, extra-cellular matrix and matrix degradation enzymes are calculated based on the haemodynamic environment which is obtained by coupled modelling of intravascular blood flow with interstitial fluid flow. The haemodynamic changes, including vessel diameter and permeability, are introduced to reflect a series of pathological characteristics of abnormal tumour vessels including vessel dilation, leakage, angiogenesis, regression and collapse. Migrating cells are included as a new phenotype to describe the migration behaviour of malignant tumour cells. The simulation focuses on the avascular phase of tumour development and stops at an early phase of angiogenesis. The model is able to demonstrate the main features of glioblastoma growth in this phase such as the formation of pseudopalisades, cell migration along the host vessels, the pre-existing vasculature co-option, angiogenesis and remodelling. The model also enables us to examine the influence of initial conditions and local environment on the early phase of glioblastoma growth. PMID:26934465

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

    PubMed

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

    2011-03-01

    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

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

    PubMed Central

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

    2010-01-01

    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

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

    PubMed Central

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

    2014-01-01

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

  7. Angioblast Derived from ES Cells Construct Blood Vessels and Ameliorate Diabetic Polyneuropathy in Mice

    PubMed Central

    Kamiya, Hideki; Naruse, Keiko; Cheng, Zhao; Ito, Sachiko; Shibata, Taiga; Kondo, Masaki; Kato, Jiro; Okawa, Tetsuji; Fujiya, Atsushi; Suzuki, Hirohiko; Kito, Tetsutaro; Hamada, Yoji; Oiso, Yutaka; Isobe, Kenichi; Nakamura, Jiro

    2015-01-01

    Background. Although numerous reports addressing pathological involvements of diabetic polyneuropathy have been conducted, a universally effective treatment of diabetic polyneuropathy has not yet been established. Recently, regenerative medicine studies in diabetic polyneuropathy using somatic stem/progenitor cell have been reported. However, the effectiveness of these cell transplantations was restricted because of their functional and numerical impairment in diabetic objects. Here, we investigated the efficacy of treatment for diabetic polyneuropathy using angioblast-like cells derived from mouse embryonic stem cells. Methods and Results. Angioblast-like cells were obtained from mouse embryonic stem cells and transplantation of these cells improved several physiological impairments in diabetic polyneuropathy: hypoalgesia, delayed nerve conduction velocities, and reduced blood flow in sciatic nerve and plantar skin. Furthermore, pathologically, the capillary number to muscle fiber ratios were increased in skeletal muscles of transplanted hindlimbs, and intraepidermal nerve fiber densities were ameliorated in transplanted plantar skin. Transplanted cells maintained their viabilities and differentiated to endothelial cells and smooth muscle cells around the injection sites. Moreover, several transplanted cells constructed chimeric blood vessels with recipient cells. Conclusions. These results suggest that transplantation of angioblast like cells induced from embryonic stem cells appears to be a novel therapeutic strategy for diabetic polyneuropathy. PMID:25977928

  8. Effect of platelet activating factor (PAF) on the formation of blood vessels in subcutaneous implants in mice.

    PubMed

    Andrade, S P; Vieira, L B; Bakhle, Y S; Piper, P J

    1994-03-01

    Angiogenesis accompanies inflammatory processes and many other pathological conditions. We have studied the effect of platelet-activating factor (PAF) a well-known inflammatory mediator, as a promoter of angiogenesis in the sponge implant model in mice. Development of blood vessels and blood flow were monitored by use of a 133Xe washout technique. The results showed PAF to have angiogenic activity, which was inhibited by WEB 2086, and the PAF-induced vasculature to have normal pharmacological reactivity. PMID:7516807

  9. Full dimensional computer simulations to study pulsatile blood flow in vessels, aortic arch and bifurcated veins: Investigation of blood viscosity and turbulent effects.

    PubMed

    Sultanov, Renat A; Guster, Dennis

    2009-01-01

    We report computational results of blood flow through a model of the human aortic arch and a vessel of actual diameter and length. A realistic pulsatile flow is used in all simulations. Calculations for bifurcation type vessels are also carried out and presented. Different mathematical methods for numerical solution of the fluid dynamics equations have been considered. The non-Newtonian behaviour of the human blood is investigated together with turbulence effects. A detailed time-dependent mathematical convergence test has been carried out. The results of computer simulations of the blood flow in vessels of three different geometries are presented: for pressure, strain rate and velocity component distributions we found significant disagreements between our results obtained with realistic non-Newtonian treatment of human blood and the widely used method in the literature: a simple Newtonian approximation. A significant increase of the strain rate and, as a result, the wall shear stress distribution, is found in the region of the aortic arch. Turbulent effects are found to be important, particularly in the case of bifurcation vessels. PMID:19964834

  10. The structural and functional effects of fine particulate matter from cooking oil fumes on rat umbilical cord blood vessels.

    PubMed

    Zhu, Xiaoxia; Hou, Lijuan; Zhang, Jian; Yao, Cijiang; Liu, Ying; Zhang, Chao; Xu, Yachun; Cao, Jiyu

    2016-08-01

    A growing body of epidemiological evidence has supported the association between maternal exposure to airborne fine particulate matter (PM2.5) during pregnancy and adverse pregnancy outcomes. However, the specific biological mechanisms implicated in the causes of adverse pregnancy outcomes are not well defined. In this study, a pregnant rat model of exposure to different doses of cooking oil fumes (COFs)-derived PM2.5 by tail intravenous injection in different pregnant stages was established. The results indicated that exposure to COFs-derived PM2.5 was associated with adverse pregnancy outcomes, changed the structure of umbilical cord blood vessels, decreased the diameter and lumen area, and increased wall thickness. What's more, a significant increase of maximum contraction tension was observed in the early pregnancy high-dose exposure group and pregnant low-dose exposure group compared to the control group. Based on the maximum contraction tension, acetylcholine (ACh) did not induce vasodilation but caused a dose-dependent constriction, and there were significant differences in the two groups compared to the control group. Exposure to COFs-derived PM2.5 impaired the vasomotor function of umbilical veins by affecting the expression of NO and ET-1. This is the first study that evaluated the association of risk of adverse pregnancy outcomes and pregnant rats exposed to COFs-derived PM2.5 and primarily explored the potential mechanisms of umbilical cord blood vessels injury on a rat model. More detailed vitro and vivo studies are needed to further explore the mechanism in the future. PMID:27178289

  11. Single image correlation for blood flow mapping in complex vessel networks

    NASA Astrophysics Data System (ADS)

    Chirico, Giuseppe; Sironi, Laura; Bouzin, Margaux; D'Alfonso, Laura; Collini, Maddalena; Ceffa, Nicolo'G.; Marquezin, Cassia

    2015-05-01

    Microcirculation plays a key role in the maintenance and hemodynamics of tissues and organs also due to its extensive interaction with the immune system. A critical limitation of state-of-the-art clinical techniques to characterize the blood flow is their lack of the spatial resolution required to scale down to individual capillaries. On the other hand the study of the blood flow through auto- or cross-correlation methods fail to correlate the flow speed values with the morphological details required to describe an intricate network of capillaries. Here we propose to use a newly developed technique (FLICS, FLow Image Correlation Spectroscopy) that, by employing a single raster-scanned xy-image acquired in vivo by confocal or multi-photon excitation fluorescence microscopy, allows the quantitative measurement of the blood flow velocity in the whole vessel pattern within the field of view, while simultaneously maintaining the morphological information on the immobile structures of the explored circulatory system. Fluorescent flowing objects produce diagonal lines in the raster-scanned image superimposed to static morphological details. The flow velocity is obtained by computing the Cross Correlation Function (CCF) of the intensity fluctuations detected in pairs of columns of the image. The whole analytical dependence of the CCFs on the flow speed amplitude and the flow direction has been reported recently. We report here the derivation of approximated analytical relations that allows to use the CCF peak lag time and the corresponding CCF value, to directly estimate the flow speed amplitude and the flow direction. The validation has been performed on Zebrafish embryos for which the flow direction was changed systematically by rotating the embryos on the microscope stage. The results indicate that also from the CCF peak lag time it is possible to recover the flow speed amplitude within 13% of uncertainty (overestimation) in a wide range of angles between the flow and

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  13. NOK/STYK1 promotes the genesis and remodeling of blood and lymphatic vessels during tumor progression.

    PubMed

    Liu, Yue; Li, Tianqi; Hu, Dan; Zhang, Shuping

    2016-09-01

    Previous studies have indicated that the overexpression of NOK, also named STYK1, led to tumorigenesis and metastasis. Here, we provide evidence that increased expression of NOK/STYK1 caused marked alterations in the overall and inner structures of tumors and substantially facilitates the genesis and remodeling of the blood and lymphatic vessels during tumor progression. In particular, NOK-expressed HeLa stable cells (HeLa-K) significantly enhanced tumor growth and metastasis in xenografted nude mice. Hematoxylin and eosin (HE) staining demonstrated that the tumor tissues generated by HeLa-K cells were much more ichorous and had more interspaces than those generated by control HeLa cells (HeLa-C). The fluorescent areas stained with cluster of differentiation 31 (CD31), a marker protein for blood vessels, appeared to be in different patterns. The total blood vessels, especially the ring patterns, within the tumors of the HeLa-K group were highly enriched compared with those in the HeLa-C group. NOK-HA was demonstrated to be well colocalized with CD31 in the wall of the tubular structures within tumor tissues. Interestingly, antibody staining of the lymphatic vessel endothelial hyaluronan receptor (LYVE-1) further revealed the increase in ring (oratretic strip-like) lymphatic vessels in either the peritumoral or intratumoral areas in the HeLa-K group compared with the HeLa-C group. Consistently, the analysis of human cancerous tissue also showed that NOK was highly expressed in the walls of tubular structures. Thus, our results reveal a novel tumorigenic function of NOK to mediate the genesis and remodeling of blood and lymphatic vessels during tumor progression. PMID:27444381

  14. Best dynamic wavelength range for shock detection via blood vessel density pattern

    NASA Astrophysics Data System (ADS)

    Kanawade, Rajesh; Saiko, Gennadiy; Douplik, Alexandre

    Diffuse reflectance spectroscopy is a non-invasive or minimally invasive medical diagnostic modality. Still challenges in noninvasive tools for early shock detection are unresolved especially in spatial resolution and broad range of sampling wavelength for reduced-/ oxy-hemoglobin concentrations detection from tissue sample. To minimize these limitations, we have developed a novel method based on spatially and spectrally resolved diffuse reflectance for shock detection. This study was performed to pick up best dynamic wavelength range sets to detect fine vessel density pattern modulation for shock detection.

  15. X-ray PIV measurement of blood flow in deep vessels of a rat: An in vivo feasibility study

    PubMed Central

    Park, Hanwook; Yeom, Eunseop; Lee, Sang Joon

    2016-01-01

    X-ray PIV measurement is a noninvasive approach to measure opaque blood flows. However, it is not easy to measure real pulsatile blood flows in the blood vessels located at deep position of the body, because the surrounding tissues significantly attenuate the contrast of X-ray images. This study investigated the effect of surrounding tissues on X-ray beam attenuation by measuring the velocity fields of blood flows in deep vessels of a live rat. The decrease in image contrast was minimized by employing biocompatible CO2 microbubbles as tracer particles. The maximum measurable velocity of blood flows in the abdominal aorta of a rat model was found through comparative examination between the PIV measurement accuracy and the level of image contrast according to the input flow rate. Furthermore, the feasibility of using X-ray PIV to accurately measure in vivo blood flows was demonstrated by determining the velocity field of blood flows in the inferior vena cava of a rat. This study may serve as a reference in conducting in vivo X-ray PIV measurements of pulsatile blood flows in animal disease models and investigating hemodynamic characteristics and circulatory vascular diseases. PMID:26777719

  16. Association of body composition and blood pressure categories with retinal vessel diameters in primary school children.

    PubMed

    Imhof, Katharina; Zahner, Lukas; Schmidt-Trucksäss, Arno; Hanssen, Henner

    2016-06-01

    Alterations in retinal vessel diameters have been shown to be predictive of cardiovascular risk in adults and children. The aim of our study was to examine the association of body composition and blood pressure (BP) categories with retinal vessel diameters in school children. We examined anthropometric parameters, BP and retinal arteriolar (CRAE) and venular (CRVE) diameters as well as the arteriolar-to-venular diameter ratio (AVR) in 391 children (age: 7.3, s.d. 0.4). Differences between the lowest and highest BP quartiles indicated that higher systolic and diastolic BP were associated with narrower CRAE (P<0.001 for both). Children in the highest weight quartile had narrower CRAE compared with the lowest quartile (P=0.05). In the regression analysis, systolic and diastolic BP were associated with arteriolar narrowing (-0.4 measuring units (mu) per mm Hg, 95% confidence interval: [-0.6; -0.3] and -0.6 mu per mm Hg [-0.7; -0.4], respectively; P<0.001 for both). An independent association was found for diastolic BP only. Compared with normotensives (NT; 74.4% of cohort), arteriolar narrowing was already seen in children categorized as pre-hypertensive (PHT) (11.5% of cohort), which was similar to HT children (14.1% of cohort) (NT: mean 207.2 [205.6; 208.7] mu; PHT: 201.7 [197.8; 205.7] mu; HT: 199.7 [196.2; 203.3] mu; P=0.01 for PHT vs. NT and P<0.001 for HT vs. NT in systolic BP). Our results suggest that systolic and diastolic BP are main determinants of retinal arteriolar diameters; and therefore, microvascular health in young children. Pre-hypertension seems to be associated with retinal microvascular alterations early in life. PMID:26763853

  17. 50 CFR Table 20 to Part 679 - Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for complete seabird avoidance program requirements; see 679.24(e)(1) for applicable fisheries) 20 Table 20 to Part 679 Wildlife and Fisheries FISHERY... Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for...

  18. 50 CFR Table 20 to Part 679 - Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for complete seabird avoidance program requirements; see 679.24(e)(1) for applicable fisheries) 20 Table 20 to Part 679 Wildlife and Fisheries FISHERY... Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for...

  19. 50 CFR Table 20 to Part 679 - Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for complete seabird avoidance program requirements; see 679.24(e)(1) for applicable fisheries) 20 Table 20 to Part 679 Wildlife and Fisheries FISHERY... Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for...

  20. 50 CFR Table 20 to Part 679 - Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for complete seabird avoidance program requirements; see 679.24(e)(1) for applicable fisheries) 20 Table 20 to Part 679 Wildlife and Fisheries FISHERY... Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for...

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

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-03-01

    High-intensity focused ultrasound (HIFU) has been shown to effectively occlude blood vessels deep within tissue. The objective of the current study was to synchronize HIFU and color-Doppler ultrasound (US) for the real-time visualization of flow within blood vessels during HIFU treatment. The excitation of the HIFU was synchronized with the color-Doppler imager by collecting the excitation pulses of one of the elements of either a curved array intracavitary (C 9-5) or an intraoperative (CL 10-5) imaging probe. The collected excitation pulse was converted into a TTL-high pulse, which was delayed and gated to time the excitation duration and location of the HIFU pulse with respect to each imaging frame. The single pulse was used to drive a 3.2 MHz concave HIFU transducer (focal length of 3.5 cm, f-number 1) while the US imager was not collecting RF signals from the treatment region of the US image. The feasibility of the system was demonstrated in vivo by the selective ablation of tissue adjacent to, or the occlusion of, large vessels (including the femoral artery) both transcutaneously and interoperatively in the rabbit and pig. For the occlusion of vessels, the HIFU focus was placed immediately distal (with respect to the transducer) to the vessel at a depth of 2-2.5 cm. HIFU was applied at in situ intensities of 1000-2000 W/cm2, at a duty cycle of 50-75%, and a HIFU pulse repetition frequency (set by the US image frame rate) of 6-18 Hz. During each HIFU exposure, the HIFU pulse resulted in color interference bands running vertically within the color-Doppler window. Through the synchronization of the US imager with the HIFU excitation, the location and duration of the interference bands were set outside the treatment region within each image frame. This provided the operator with a clear view of the HIFU treatment site during therapy. Gross assessment showed necrosis of the tissue surrounding the HIFU treated vessel and occlusion of vessels up to 4 mm in diameter

  3. Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

    PubMed Central

    BUSSAU, L. J.; VO, L. T.; DELANEY, P. M.; PAPWORTH, G. D.; BARKLA, D. H.; KING, R. G.

    1998-01-01

    Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible. PMID:9643419

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

    PubMed Central

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

    2012-01-01

    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

  5. Nanostructural haemocompatible coatings for the internal side of artificial blood vessels

    NASA Astrophysics Data System (ADS)

    Trembecka-Wojciga, K.; Major, R.; Lackner, J. M.; Butruk-Raszeja, B.; Sanak, M.; Major, B.

    2016-03-01

    The main goal of the work was to elaborate low thrombogenicity of surface inside tube-like elements for cardiovascular system support by combination of low-temperature glow discharge and hydrogel coatings to inhibit blood-clotting cascade activation. A large share of amorphous phase silicon was observed in the microstructure analysis. The crystalline elements were uniformly distributed in the amorphous structure. Combination of low thickness, the proper microstructure and density of the coatings provided a highly flexible nature of the whole system. The blood-material interaction was analyzed in vitro in dynamic conditions by using a designed and fabricated novel blood flow simulator. Coatings deposited by the glow discharge expressed good hemocopatibile properties. The use of hydrogel coatings did not reduce coagulation parameter. Hydrogel coatings did not improve the hemocompatibility of the surface modified with carbon based coatings. Modification of surface with hydrogel resulted in further increased risk of hemolysis.

  6. Transport of membrane-bound mineral particles in blood vessels during chicken embryonic bone development.

    PubMed

    Kerschnitzki, Michael; Akiva, Anat; Ben Shoham, Adi; Koifman, Naama; Shimoni, Eyal; Rechav, Katya; Arraf, Alaa A; Schultheiss, Thomas M; Talmon, Yeshayahu; Zelzer, Elazar; Weiner, Stephen; Addadi, Lia

    2016-02-01

    During bone formation in embryos, large amounts of calcium and phosphate are taken up and transported to the site where solid mineral is first deposited. The initial mineral forms in vesicles inside osteoblasts and is deposited as a highly disordered calcium phosphate phase. The mineral is then translocated to the extracellular space where it penetrates the collagen matrix and crystallizes. To date little is known about the transport mechanisms of calcium and phosphate in the vascular system, especially when high transport rates are needed and the concentrations of these ions in the blood serum may exceed the solubility product of the mineral phase. Here we used a rapidly growing biological model, the chick embryo, to study the bone mineralization pathway taking advantage of the fact that large amounts of bone mineral constituents are transported. Cryo scanning electron microscopy together with cryo energy dispersive X-ray spectroscopy and focused-ion beam imaging in the serial surface view mode surprisingly reveal the presence of abundant vesicles containing small mineral particles in the lumen of the blood vessels. Morphologically similar vesicles are also found in the cells associated with bone formation. This observation directly implicates the vascular system in solid mineral distribution, as opposed to the transport of ions in solution. Mineral particle transport inside vesicles implies that far larger amounts of the bone mineral constituents can be transported through the vasculature, without the danger of ectopic precipitation. This introduces a new stage into the bone mineral formation pathway, with the first mineral being formed far from the bone itself. PMID:26481471

  7. MCAM and LAMA4 Are Highly Enriched in Tumor Blood Vessels of Renal Cell Carcinoma and Predict Patient Outcome.

    PubMed

    Wragg, Joseph W; Finnity, Jonathan P; Anderson, Jane A; Ferguson, Henry J M; Porfiri, Emilio; Bhatt, Rupesh I; Murray, Paul G; Heath, Victoria L; Bicknell, Roy

    2016-04-15

    The structure and molecular signature of tumor-associated vasculature are distinct from those of the host tissue, offering an opportunity to selectively target the tumor blood vessels. To identify tumor-specific endothelial markers, we performed a microarray on tumor-associated and nonmalignant endothelium collected from patients with renal cell carcinoma (RCC), colorectal carcinoma, or colorectal liver metastasis. We identified a panel of genes consistently upregulated by tumor blood vessels, of which melanoma cell adhesion molecule (MCAM) and its extracellular matrix interaction partner laminin alpha 4 (LAMA4) emerged as the most consistently expressed genes. This result was subsequently confirmed by immunohistochemical analysis of MCAM and LAMA4 expression in RCC and colorectal carcinoma blood vessels. Strong MCAM and LAMA4 expression was also shown to predict poor survival in RCC, but not in colorectal carcinoma. Notably, MCAM and LAMA4 were enhanced in locally advanced tumors as well as both the primary tumor and secondary metastases. Expression analysis in 18 different cancers and matched healthy tissues revealed vascular MCAM as highly specific in RCC, where it was induced strongly by VEGF, which is highly abundant in this disease. Lastly, MCAM monoclonal antibodies specifically localized to vessels in a murine model of RCC, offering an opportunity for endothelial-specific targeting of anticancer agents. Overall, our findings highlight MCAM and LAMA4 as prime candidates for RCC prognosis and therapeutic targeting. Cancer Res; 76(8); 2314-26. ©2016 AACR. PMID:26921326

  8. Insulin-like Growth Factor 1 (IGF-1) Stabilizes Nascent Blood Vessels*

    PubMed Central

    Jacobo, Sarah Melissa P.; Kazlauskas, Andrius

    2015-01-01

    Here we report that VEGF-A and IGF-1 differ in their ability to stabilize newly formed blood vessels and endothelial cell tubes. Although VEGF-A failed to support an enduring vascular response, IGF-1 stabilized neovessels generated from primary endothelial cells derived from various vascular beds and mouse retinal explants. In these experimental systems, destabilization/regression was driven by lysophosphatidic acid (LPA). Because previous studies have established that Erk antagonizes LPA-mediated regression, we considered whether Erk was an essential component of IGF-dependent stabilization. Indeed, IGF-1 lost its ability to stabilize neovessels when the Erk pathway was inhibited pharmacologically. Furthermore, stabilization was associated with prolonged Erk activity. In the presence of IGF-1, Erk activity persisted longer than in the presence of VEGF or LPA alone. These studies reveal that VEGF and IGF-1 can have distinct inputs in the angiogenic process. In contrast to VEGF, IGF-1 stabilizes neovessels, which is dependent on Erk activity and associated with prolonged activation. PMID:25564613

  9. Blood-Brain Barrier Dysfunction and Cerebral Small Vessel Disease (Arteriolosclerosis) in Brains of Older People

    PubMed Central

    Khoong, Cheryl H.L.; Poon, Wayne; Esiri, Margaret M.; Markus, Hugh S.; Hainsworth, Atticus H.

    2014-01-01

    The blood-brain barrier (BBB) protects brain tissue from potentially harmful plasma components. Small vessel disease ([SVD], 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 IgG, which are assumed to reflect BBB dysfunction, in deep grey matter (anterior caudate-putamen, [DGM]) and deep subcortical white matter (DWM) in the brains of a well-characterized patient cohort with minimal Alzheimer disease pathology (Braak stage 0-II) (n = 84; age ≥65 years). Morphometric measures of fibrinogen labeling were compared between people with neuropathologically defined SVD and aged control subjects. Parenchymal cellular labeling with fibrinogen and IgG 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 BBB dysfunction is common but do not support an association with SVD. PMID:25289893

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

    PubMed

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

    2014-12-01

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

  11. Thermal expansion of vitrified blood vessels permeated with DP6 and synthetic ice modulators.

    PubMed

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

    2014-06-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    We have proposed a physical DDS (Drug Delivery System) which makes use of microcapsules of μm 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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

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

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

    SciTech Connect

    Tompkins, R.G.; Yarmush, M.L.; Schnitzer, J.J.; Colton, C.K.; Smith, K.A.; Stemerman, M.B. )

    1989-08-01

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

  16. CCL11-induced eosinophils inhibit the formation of blood vessels and cause tumor necrosis.

    PubMed

    Xing, Yanjiang; Tian, Yijun; Kurosawa, Takamasa; Matsui, Sayaka; Touma, Maki; Yanai, Takanori; Wu, Qiong; Sugimoto, Kenkichi

    2016-06-01

    We previously demonstrated that IL-18 and CCL11 were highly expressed in an NFSA tumor cell line that showed limited angiogenesis and severe necrosis. However, IL-18 was not responsible for the immune cell accumulation and necrosis. Here, we attempted to clarify the relevance of CCL11 in angiogenesis and tumor formation. We established CCL11-overexpressing MS-K cell clones (MS-K-CCL11) to assess the role of CCL11 in immune cell accumulation and angiogenesis. The MS-K-CCL11 cells did not form tumors in mice. MS-K-CCL11-conditioned medium (CM) and recombinant CCL11 induced macrophage and eosinophil differentiation from bone marrow cells. The MS-K-CCL11-CM effectively recruited the differentiated eosinophils. Furthermore, the eosinophils damaged the MS-K, NFSA and endothelial cells in a dose-dependent manner. Administration of an antagonist of CCR3, a CCL11 receptor, to NFSA tumor-bearing mice restored the blood vessel formation and blocked the eosinophil infiltration into the NFSA tumors. Furthermore, other CCL11-overexpressing LM8 clones were established, and their tumor formation ability was reduced compared to the parental LM8 cells, accompanied by increased eosinophil infiltration, blockade of angiogenesis and necrosis. These results indicate that CCL11 was responsible for the limited angiogenesis and necrosis by inducing and attracting eosinophils in the tumors. PMID:27169545

  17. The effect of maternal smoke exposure on the ultrastructure of fetal peripheral blood vessels in the mouse.

    PubMed

    Kaufmann, R C; Amankwah, K S; Weberg, A D

    1986-01-01

    Ultrastructural changes have been found in umbilical blood vessels, placental blood vessels, and peripheral blood vessels of human fetuses whose mothers smoked during pregnancy. This study was undertaken to determine if similar changes could be found in peripheral blood vessels of mice fetuses whose mothers were exposed to cigarette smoke during pregnancy. Breeding mice of the C57BL/KsJ strain were placed in a smoking box similar to that described by Younoszai and exposed to cigarette smoke intermittently. This produces carbon monoxide levels in the adult mice similar to that found in human adults smoking one pack of cigarettes per day. Similarly caged mice of the same strain were used as controls. The female mice were not removed from their cage from pre-conception time until after delivery. Upon delivery each pup was sacrificed via neck fracture and the entire pup was immersed in a solution of 2.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.3. While still under solution, the rear leg muscles were dissected free, sliced, and immersed in the same preservative for four to five hours. They were then placed in fresh 2.5% glutaraldehyde mixture overnight. The tissues were post-fixed in osmium ferrocyanide and en-block stained with uranyl acetate in a graded series of alcohol. The tissues were infiltrated with and embedded in Spurr. Sections were taken via an ultramicrotome and post-stained with uranyl acetate and lead citrate. The sections were examined in a Philips 201 electron microscope at 60 KV. In the peripheral vessels of the fetuses from smoke-exposed mothers, endothelial blebbing (both surface-type and vacuole-type) was seen.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3783394

  18. Due to intravascular multiple sequential scattering, Diffuse Correlation Spectroscopy of tissue primarily measures relative red blood cell motion within vessels.

    PubMed

    Carp, Stefan A; Roche-Labarbe, Nadàege; Franceschini, Maria-Angela; Srinivasan, Vivek J; Sakadžić, Sava; Boas, David A

    2011-07-01

    We suggest that Diffuse Correlation Spectroscopy (DCS) measurements of tissue blood flow primarily probe relative red blood cell (RBC) motion, due to the occurrence of multiple sequential scattering events within blood vessels. The magnitude of RBC shear-induced diffusion is known to correlate with flow velocity, explaining previous reports of linear scaling of the DCS "blood flow index" with tissue perfusion despite the observed diffusion-like auto-correlation decay. Further, by modeling RBC mean square displacement using a formulation that captures the transition from ballistic to diffusive motion, we improve the fit to experimental data and recover effective diffusion coefficients and velocity de-correlation time scales in the range expected from previous blood rheology studies. PMID:21750779

  19. The Relationship of Retinal Vessel Diameters and Fractal Dimensions with Blood Pressure and Cardiovascular Risk Factors

    PubMed Central

    Li, Qiaowei; Yuan, Yin; Gao, Zhonghai; Chen, Falin

    2014-01-01

    Background This study aimed to investigate the correlation between quantitative retinal vascular parameters such as central retinal arteriolar equivalent (CRAE) and retinal vascular fractal dimension (D(f)), and cardiovascular risk factors in the Chinese Han population residing in the in islands of southeast China. Methodology/Principle Findings In this cross-sectional study, fundus photographs were collected and semi-automated analysis software was used to analyze retinal vessel diameters and fractal dimensions. Cardiovascular risk factors such as relevant medical history, blood pressure (BP), lipids, and blood glucose data were collected. Subjects had a mean age of 51.9±12.0 years and included 812 (37.4%) males and 1,357 (62.6%) females. Of the subjects, 726 (33.5%) were overweight, 226 (10.4%) were obese, 272 (12.5%) had diabetes, 738 (34.0%) had hypertension, and 1,156 (53.3%) had metabolic syndrome. After controlling for the effects of potential confounders, multivariate analyses found that age (β = 0.06, P = 0.008), sex (β = 1.33, P = 0.015), mean arterial blood pressure (β = −0.12, P<0.001), high-sensitivity C-reactive protein (β = −0.22, P = 0.008), and CRVE (β = 0.23, P<0.001) were significantly associated with CRAE. Age (β = −0.0012, P<0.001), BP classification (prehypertension: β = −0.0075, P = 0.014; hypertension: β = −0.0131, P = 0.002), and hypertension history (β = −0.0007, P = 0.009) were significantly associated with D(f). Conclusions/Significance D(f) exhibits a stronger association with BP than CRAE. Thus, D(f) may become a useful indicator of cardiovascular risk. PMID:25188273

  20. Malformation of certain brain blood vessels caused by TCDD activation of Ahr2/Arnt1 signaling in developing zebrafish

    PubMed Central

    Teraoka, Hiroki; Ogawa, Akira; Kubota, Akira; Stegeman, John J.; Peterson, Richard E.; Hiraga, Takeo

    2011-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). The AHR also plays important roles in normal development in mice, and AHR-/- mice show abnormal development of vascular structures in various blood vessels. Our previous studies revealed that Ahr type 2 (Ahr2) activation by TCDD and β-naphthoflavone (BNF) caused a significant decrease in blood flow in the dorsal midbrain of zebrafish embryos. Here we report effects of TCDD exposure on the morphology of some blood vessels in the head of developing zebrafish. TCDD caused concentration-dependent anatomical rearrangements in the shape of the prosencephalic artery in zebrafish larvae. In contrast, no major vascular defects were recognized in the trunk and tail regions following exposure to TCDD at least at the concentrations used. Essentially, the same observations were also confirmed in BNF-exposed larvae. Knock-down of either Ahr2 or Ahr nuclear translocator type 1 (Arnt1) by morpholino oligonucleotides (MOs) protected larvae against abnormal shape of the prosencephalic artery caused by TCDD and BNF. On the other hand, knock-down of Ahr2 or Arnt1 in vehicle-exposed zebrafish larvae had no clear effect on morphology of the prosencephalic artery or trunk vessels. Ascorbic acid, an antioxidant, protected against the TCDD-induced decrease in blood flow through the prosencephalic artery, but not the abnormal morphological changes in the shape of this artery. These results indicate that activation of Ahr2/Arnt1 pathway by TCDD and BNF affects the shape of certain blood vessels in the brain of developing zebrafish. PMID:20554057

  1. Analysis by NASA's VESGEN Software of Retinal Blood Vessels Before and After 70-Day Bed Rest: A Retrospective Study

    NASA Technical Reports Server (NTRS)

    Raghunandan, Sneha; Vyas, Ruchi J.; Vizzeri, Gianmarco; Taibbi, Giovanni; Zanello, Susana B.; Ploutz-Snyder, Robert; Parsons-Wingerter, Patricia A.

    2016-01-01

    Significant risks for visual impairment associated with increased intracranial pressure (VIIP) are incurred by microgravity spaceflight, especially long-duration missions. Impairments include decreased near visual acuity, posterior globe flattening, choroidal folds, optic disc edema and cotton wool spots. We hypothesize that microgravity-induced fluid shifts result in pathological changes within the retinal blood vessels that precede development of visual and other ocular impairments. Potential contributions of retinal vascular remodeling to VIIP etiology are therefore being investigated by NASAs innovative VESsel GENeration Analysis (VESGEN) software for two studies: (1) head-down tilt in human subjects before and after 70 days of bed rest, and (2) U.S. crew members before and after ISS missions. VESGEN analysis in previous research supported by the US National Institutes of Health identified surprising new opportunities to regenerate retinal vessels during early-stage, potentially reversible progression of the visually impairing and blinding disease, diabetic retinopathy.

  2. Changes in the rheological properties of blood vessel tissue remodeling in the course of development of diabetes.

    PubMed

    Liu, S Q; Fung, Y C

    1992-01-01

    Rheological properties of blood vessels are expected to change in disease process if the structure of the vessel wall changes. This is illustrated in diabetes, which can be induced in rat by a single injection of Streptozocin. One of the rheological properties of the blood vessel is the stress-strain relationship. The nonlinear stress-strain relationship of arteries is best expressed as derivations of a strain-energy function. In this paper, the stress-strain relations are measured and the coefficients in the strain energy function of arteries are determined for diabetic and control rats. The meaning of these coefficients are explained. The influence of diabetes on the elastic property of the arteries is expressed by the changes of these coefficients. A point of departure of the present paper from all other blood vessel papers published so far is that all strains used here are referred to the zero-stress state of the arteries, whereas all other papers refer strains to the no-load state. The existence of a large difference between the zero-stress state and no-load state of arteries is one of our recent findings. We have explained that the use of zero-stress state as a basis of strain measurements reveals that the in vivo circumferential stress distribution is quite uniform in the vessel wall at the homeostatic condition. It also makes the strain energy function much more accurate than those in which the residual stress is ignored. Using these new results, the stress and strain distribution in normal and diabetic arteries are presented. PMID:1306372

  3. Ex vivo bubble production from ovine large blood vessels: size on detachment and evidence of "active spots".

    PubMed

    Arieli, R; Marmur, A

    2014-08-15

    Nanobubbles formed on the hydrophobic silicon wafer were shown to be the source of gas micronuclei from which bubbles evolved during decompression. Bubbles were also formed after decompression on the luminal surface of ovine blood vessels. Four ovine blood vessels: aorta, pulmonary vein, pulmonary artery, and superior vena cava, were compressed to 1013 kPa for 21 h. They were then decompressed, photographed at 1-s intervals, and bubble size was measured on detachment. There were certain spots at which bubbles appeared, either singly or in a cluster. Mean detachment diameter was between 0.7 and 1.0 mm. The finding of active spots at which bubbles nucleate is a new, hitherto unreported observation. It is possible that these are the hydrophobic spots at which bubbles nucleate, stabilise, and later transform into the gas micronuclei that grow into bubbles. The possible neurological effects of these large arterial bubbles should be further explored. PMID:24933644

  4. Sinusoïdal flow of blood in a cylindrical deformable vessel exposed to an external magnetic field

    NASA Astrophysics Data System (ADS)

    Drochon, Agnès

    2016-03-01

    The present work provides an analytical solution for the Sinusoïdal flow of blood in a cylindrical elastic vessel exposed to an external magnetic field. The vessel is supposed to have non-conducting walls and the induced electric and magnetic fields are neglected. In other words, the well-known calculation of Womersley is revisited through the inclusion of the Lorentz force in the Navier-Stokes equations. A dispersion equation is obtained. This equation admits two types of solutions: the Young waves (mainly associated with radial deformation of the vessel) and the Lamb waves (mainly associated with longitudinal displacements in the vessel wall). It is demonstrated that the external magnetic field has an influence on the wave celerities, on the fluid velocity profiles, and on the wall displacements. It tends to reduce the blood flow and flatten the velocity profile, in the case of Young waves. The pulsatile character of the flow is also dampened. However, these effects become detectable for high values of the Hartmann number (M > 4, corresponding to B0 > 36 T with numerical data pertaining to large human arteries) and remain negligible in the context of magnetic resonance imaging (B0 ≤ 3 T, or even 7 T).

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

    NASA Astrophysics Data System (ADS)

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

    2003-10-01

    Background: Coronary artery disease (CAD) is the leading cause of mortality and morbidity in the industrialized world. Optical coherence tomography (OCT) is a high-resolution intravascular imaging technology with a potential for in vivo plaque characterization. Although structural remodeling of the arterial vessel wall during plaque development can change tissue optical scattering properties, very limited evidence is available on the exact optical scattering properties of plaques. The scattering coefficient, μs, and the anisotropy factor, g, can be derived from OCT images by fitting a theoretical model to individual depth-scans. The aim of the current study was to use this method to examine by OCT the scattering properties of human arteries with different stages of atherosclerotic lesion development. Methods: Normal (n=4), lipid-rich (n=4), and fibrous (n=3) aortic blocks as classified by parallel histopathologic examination were obtained within 24 hours of death and imaged by OCT. The intima was located in the OCT images, and then further split into 115 blocks (41 normal, 40 lipid-rich, and 34 fibrous) of adjacent OCT depth-scans transversely spanning ~200-300 μm. Scattering signals from each block were averaged and fit to the theoretical model. From these fittings, μs and g were extracted. Results and Discussion: The optical scattering properties of normal aortic intima were quite different from lipid-rich and fibrous lesions, respectively. We discovered that the normal intima was generally highly forward scattering, i.e., with 0.917vessels were much less so. Furthermore, normal vessels usually had 15<μs<39 mm-1, whereas lipid-rich blocks had μs<15mm-1. Fibrous blocks displayed large variations in μs, reflecting a histopathology with varying amounts of collagen, lipids, and elastin. Based on our findings, we defined a criteria of μs and g for normal intimas, using the above values of μs and g as cutoffs. Our "normal" criteria

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

    PubMed Central

    Smiley, Dia A.; Khalil, Raouf A.

    2010-01-01

    estrogen in the aging blood vessels and thereby enhancing the efficacy and safety of MHT in postmenopausal CVD. PMID:19442151

  7. Relation of Blood Pressure to Retinal Vessel Diameter in Type 1 Diabetes Mellitus

    PubMed Central

    Klein, Ronald; Myers, Chelsea E.; Klein, Barbara E. K.; Zinman, Bernard; Gardiner, Robert; Suissa, Samy; Sinaiko, Alan R.; Donnelly, Sandra M.; Goodyer, Paul; Strand, Trudy; Mauer, Michael

    2009-01-01

    Objective To examine the relationship of blood pressure (BP) and use of angiotensin receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACEI) to retinal vessel diameter in normotensive, normoalbuminuric persons with type 1 diabetes mellitus (T1DM). Design Randomized controlled clinical trial. Participants Persons with T1DM and gradable fundus photographs both at baseline (n=147) and 5-year follow-up (n=124). Methods Clinic and 24-hour ambulatory BPs (ABP) were measured. Retinal arteriolar and venular diameters were measured using a computer-assisted technique. Individual arteriolar and venular measurements were combined into summary indices that reflect the average retinal arteriolar (central retinal arteriolar equivalent [CRAE]) and venular (central retinal venular equivalent [CRVE]) diameter of an eye, respectively. Main Outcome Measures CRAE and CRVE. Results While controlling for age, study site, glycosylated hemoglobin and ambulatory pulse rate, daytime ambulatory systolic (-0.29 μm effect per 1mmHg, P=.02) and daytime ambulatory diastolic (-0.44 μm effect per 1mmHg, P=.04), nighttime ambulatory systolic (-0.27 μm effect per 1mmHg, P=.03), and 24-hour ambulatory systolic BP (-0.31 μm effect per 1mmHg, P=.03) were cross-sectionally associated with a smaller CRAE. While controlling for age, study site, glycosylated hemoglobin, ambulatory pulse rate and baseline CRAE, no BP measure was associated with a change in CRAE or CRVE over 5 years of follow-up. Treatment with losartan or enalapril was not associated with a statistically significant change in CRAE or CRVE. Conclusions ACEI or ARB therapy does not affect retinal arteriolar or venular diameter in normotensive persons with T1DM. PMID:20142543

  8. Effects of viscosity and constraints on the dispersion and dissipation of waves in large blood vessels. I.

    NASA Technical Reports Server (NTRS)

    Jones, E.; Anliker, M.; Chang, I.

    1971-01-01

    Investigation of the effects of blood viscosity on dissipation as well as dispersion of small waves in arteries and veins by means of a parametric study. A linearized analysis of axisymmetric waves in a cylindrical membrane that contains a viscous fluid indicates that there are two families of waves: a family of slow waves and one of fast waves. The faster waves are shown to be more sensitive to variations in the elastic properties of the medium surrounding the blood vessels and at high values of the frequency parameter alpha. At low values of alpha the effects of viscosity on attenuation are reversed.

  9. Reducing the data: Analysis of the role of vascular geometry on blood flow patterns in curved vessels

    NASA Astrophysics Data System (ADS)

    Alastruey, Jordi; Siggers, Jennifer H.; Peiffer, Véronique; Doorly, Denis J.; Sherwin, Spencer J.

    2012-03-01

    Three-dimensional simulations of blood flow usually produce such large quantities of data that they are unlikely to be of clinical use unless methods are available to simplify our understanding of the flow dynamics. We present a new method to investigate the mechanisms by which vascular curvature and torsion affect blood flow, and we apply it to the steady-state flow in single bends, helices, double bends, and a rabbit thoracic aorta based on image data. By calculating forces and accelerations in an orthogonal coordinate system following the centreline of each vessel, we obtain the inertial forces (centrifugal, Coriolis, and torsional) explicitly, which directly depend on vascular curvature and torsion. We then analyse the individual roles of the inertial, pressure gradient, and viscous forces on the patterns of primary and secondary velocities, vortical structures, and wall stresses in each cross section. We also consider cross-sectional averages of the in-plane components of these forces, which can be thought of as reducing the dynamics of secondary flows onto the vessel centreline. At Reynolds numbers between 50 and 500, secondary motions in the directions of the local normals and binormals behave as two underdamped oscillators. These oscillate around the fully developed state and are coupled by torsional forces that break the symmetry of the flow. Secondary flows are driven by the centrifugal and torsional forces, and these are counterbalanced by the in-plane pressure gradients generated by the wall reaction. The viscous force primarily opposes the pressure gradient, rather than the inertial forces. In the axial direction, and depending on the secondary motion, the curvature-dependent Coriolis force can either enhance or oppose the bulk of the axial flow, and this shapes the velocity profile. For bends with little or no torsion, the Coriolis force tends to restore flow axisymmetry. The maximum circumferential and axial wall shear stresses along the centreline

  10. Structural fragility of blood vessels and peritoneum in calponin h1-deficient mice, resulting in an increase in hematogenous metastasis and peritoneal dissemination of malignant tumor cells.

    PubMed

    Taniguchi, S; Takeoka, M; Ehara, T; Hashimoto, S; Shibuki, H; Yoshimura, N; Shigematsu, H; Takahashi, K; Katsuki, M

    2001-10-15

    We have observed weak expression of calponin h1, which stabilizes the actin filament system, in blood vessels within human malignant tumors. This observation suggested that because of a deficiency in stabilization by calponin h1, the structure of blood vessels in malignant tumors is fragile compared with blood vessels in normal tissues. We therefore generated calponin h1-deficient (CN(-/-)) mice to examine the effect of calponin h1 on the integrity of the barrier system in blood vessels against cancer metastasis. The CN(-/-) mice exhibited morphological fragility of the tissues, including the uterus and blood vessels. In particular, we frequently observed bleeding into the surrounding tissue from blood vessels of the ocular fundus in CN(-/-) mice. In addition, mesothelial cells, which usually express calponin h1 in normal (CN(+/+)) mice, were retracted in the CN(-/-) mice. When fluorescein was injected i.v. into mice, the CN(-/-) mice exhibited a greater and more rapid leakage of fluorescein from the blood vessels of the ocular fundus compared with the CN(+/+) mice. In the CN(-/-) mice receiving i.v. inoculations of B16 melanoma cells, significantly more metastatic nodules were formed in the lung than in the CN(+/+) mice. When B16 melanoma cells were injected i.p., the severity of peritonitis carcinomatosa was greater in CN(-/-) than in CN(+/+) mice. These results indicate that calponin h1 plays an important role in the regulation of the integrity of the blood vessels and peritoneum, which in turn is an important factor influencing the frequency of cancer metastasis. The CN(-/-) mice, which exhibit fragile blood vessels and peritoneum, could serve as sensitive and useful host models to investigate cancer metastasis. PMID:11606404

  11. Active induction of in vivo microbubbles by acoustic radiation force at the bifurcation of blood vessel and its evaluation.

    PubMed

    Masuda, Kohji; Koido, Jun; Miyazawa, Shinya; Wada, Hikaru; Hosaka, Naoto; Mochizuki, Takashi

    2015-08-01

    Alhough the development of drug delivery system using microbubbles and ultrasound is expected, because microbubbles diffuse in bloodstream, we have so far reported our attempts for active control of the microbubbles in flow by acoustic radiation force in order to increase local concentration of the microbubbles. However, there was no evidence that in vivo microbubbles act as similar as in vitro experiments, because there were limitations for reproduction of in vivo conditions. In this study, we have elucidated the relationship between brightness variation and microbubbles concentration in the suspension to estimate the absolute concentration in an invisible condition considering in vivo experiment. Then we conducted an experiment of active induction of microbubbles in a Y-form bifurcation of artificial blood vessel, where experimental conditions were with focused ultrasound, the central frequency of 5 MHz, flow velocity of 30 mm/s, and maximum sound pressure of 300 kPa-pp, respectively. Then we applied the conditions for active induction of in vivo microbubbles to compare with in vitro experiments. We used a bifurcation of blood vessel in an ear of a rabbit because the bifurcation shape in its blood vessel is visible. As the results of the experiment, the microbubbles concentration in the induced path was almost two times higher than that in the other path, which agrees with the results from in vitro experiments. PMID:26736523

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

    PubMed Central

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

    2014-01-01

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

  13. Modeling the Role of the Glymphatic Pathway and Cerebral Blood Vessel Properties in Alzheimer’s Disease Pathogenesis

    PubMed Central

    Kyrtsos, Christina Rose; Baras, John S.

    2015-01-01

    Alzheimer’s disease (AD) is the most common cause of dementia in the elderly, affecting over 10% population over the age of 65 years. Clinically, AD is described by the symptom set of short term memory loss and cognitive decline, changes in mentation and behavior, and eventually long-term memory deficit as the disease progresses. On imaging studies, significant atrophy with subsequent increase in ventricular volume have been observed. Pathology on post-mortem brain specimens demonstrates the classic findings of increased beta amyloid (Aβ) deposition and the presence of neurofibrillary tangles (NFTs) within affected neurons. Neuroinflammation, dysregulation of blood-brain barrier transport and clearance, deposition of Aβ in cerebral blood vessels, vascular risk factors such as atherosclerosis and diabetes, and the presence of the apolipoprotein E4 allele have all been identified as playing possible roles in AD pathogenesis. Recent research has demonstrated the importance of the glymphatic system in the clearance of Aβ from the brain via the perivascular space surrounding cerebral blood vessels. Given the variety of hypotheses that have been proposed for AD pathogenesis, an interconnected, multilayer model offers a unique opportunity to combine these ideas into a single unifying model. Results of this model demonstrate the importance of vessel stiffness and heart rate in maintaining adequate clearance of Aβ from the brain. PMID:26448331

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

    PubMed Central

    Kothapalli, Sri-Rajasekhar; Wang, Lihong V.

    2009-01-01

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

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

    PubMed

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

    2011-07-01

    Uncovering principles that regulate energy metabolism in the brain requires mapping of partial pressure of oxygen (PO(2)) 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 PO(2) can be accurately measured in the brain at depths up to 300 μm with micron-scale resolution. In addition, 2PLM allowed simultaneous measurements of blood flow and of PO(2) 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 PO(2) in capillaries and by a biphasic PO(2) response in the neuropil, consisting of an 'initial dip' and a rebound. 2PLM of PO(2) opens new avenues for studies of brain metabolism and blood flow regulation. PMID:21642977

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

    PubMed Central

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

    2012-01-01

    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 μm 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

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

    PubMed Central

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

    2014-01-01

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

  18. A quantum mechanics-based algorithm for vessel segmentation in retinal images

    NASA Astrophysics Data System (ADS)

    Youssry, Akram; El-Rafei, Ahmed; Elramly, Salwa

    2016-03-01

    Blood vessel segmentation is an important step in retinal image analysis. It is one of the steps required for computer-aided detection of ophthalmic diseases. In this paper, a novel quantum mechanics-based algorithm for retinal vessel segmentation is presented. The algorithm consists of three major steps. The first step is the preprocessing of the images to prepare the images for further processing. The second step is feature extraction where a set of four features is generated at each image pixel. These features are then combined using a nonlinear transformation for dimensionality reduction. The final step is applying a recently proposed quantum mechanics-based framework for image processing. In this step, pixels are mapped to quantum systems that are allowed to evolve from an initial state to a final state governed by Schrödinger's equation. The evolution is controlled by the Hamiltonian operator which is a function of the extracted features at each pixel. A measurement step is consequently performed to determine whether the pixel belongs to vessel or non-vessel classes. Many functional forms of the Hamiltonian are proposed, and the best performing form was selected. The algorithm is tested on the publicly available DRIVE database. The average results for sensitivity, specificity, and accuracy are 80.29, 97.34, and 95.83 %, respectively. These results are compared to some recently published techniques showing the superior performance of the proposed method. Finally, the implementation of the algorithm on a quantum computer and the challenges facing this implementation are introduced.

  19. A quantum mechanics-based algorithm for vessel segmentation in retinal images

    NASA Astrophysics Data System (ADS)

    Youssry, Akram; El-Rafei, Ahmed; Elramly, Salwa

    2016-06-01

    Blood vessel segmentation is an important step in retinal image analysis. It is one of the steps required for computer-aided detection of ophthalmic diseases. In this paper, a novel quantum mechanics-based algorithm for retinal vessel segmentation is presented. The algorithm consists of three major steps. The first step is the preprocessing of the images to prepare the images for further processing. The second step is feature extraction where a set of four features is generated at each image pixel. These features are then combined using a nonlinear transformation for dimensionality reduction. The final step is applying a recently proposed quantum mechanics-based framework for image processing. In this step, pixels are mapped to quantum systems that are allowed to evolve from an initial state to a final state governed by Schrödinger's equation. The evolution is controlled by the Hamiltonian operator which is a function of the extracted features at each pixel. A measurement step is consequently performed to determine whether the pixel belongs to vessel or non-vessel classes. Many functional forms of the Hamiltonian are proposed, and the best performing form was selected. The algorithm is tested on the publicly available DRIVE database. The average results for sensitivity, specificity, and accuracy are 80.29, 97.34, and 95.83 %, respectively. These results are compared to some recently published techniques showing the superior performance of the proposed method. Finally, the implementation of the algorithm on a quantum computer and the challenges facing this implementation are introduced.

  20. [Blood vessels of the periodontium of incisors and molars of the lower jaw of the white rat].

    PubMed

    Varshavskiĭ, A I

    1985-12-01

    By means of injective and noninjective methods, the structural organization of the incisor and molar blood bed has been studied in the white rat mandible. For the periodontal blood bed, distinguishing by a pronounced organo-specificity, distribution of arterial and venous vessels between collagenous fiber bundles and a reticular arrangement of the capillaries is peculiar. A definite connection is clearly seen between angioarchitectonics of different segments of the periodontium, its structure and function. Unequal density of the capillary networks in the area of the epithelial dental organ and difference of the periodontal angioarchitectonics with the lingual and labial surfaces of the incisors are noted. The area of the epithelial dental organ, having a peculiar functional importance, is characterized by multiple pathways of blood inflow and outflow, by concentration of structural-functional adaptations which increase expansiveness, capacity and diffusive surface of metabolic microvessels, by a small critical thickness of the tissue layer between neighbouring capillaries. PMID:4091685

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

    NASA Astrophysics Data System (ADS)

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

    1999-04-01

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

  2. The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels.

    PubMed

    Lehner, C; Gehwolf, R; Ek, J C; Korntner, S; Bauer, H; Bauer, H C; Traweger, A; Tempfer, H

    2016-01-01

    Tissue barriers function as "gate keepers" between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies. PMID:27227787

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

    PubMed

    Müller, Lucas O; Toro, Eleuterio F

    2013-12-01

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

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

    PubMed

    Ozdemir, V; Cevik-Demirkan, A; Türkmenoğlu, I

    2008-04-01

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

  5. Evidence for central innervation of intracerebral blood vessels: local cerebral blood flow measurements and histofluorescence analysis by the sucrose-phosphate-glyoxylic acid (SPG) method.

    PubMed

    de la Torre, J C

    1976-12-01

    Local cerebral blood flow using a hydrogen clearance technique and a histofluorescent modification of the glyoxylic acid method (SPG method) were used in rats to study the influence of brain stem centers on intracerebral flood flow. Recording of local cerebral blood flow following stimulation of the locus coeruleus but not of the ventrocaudal nucleus of the lateral lemniscus showed a significant blood flow decrease in anterior brain regions where innervation of ascending adrenergic pathways are known to occur. Adrenergic innervation using the SPG method (sucrose-potassium phosphate-glyoxylic acid) histofluorescence could not be verified in the rat but was evident in the dog and rhesus monkey brain sections examined. The results provide additional evidence suggestive of a role for the locus coeruleus in modulating or controlling intracerebral blood flow in these animals. In addition, histofluorescent visualization of intracerebral vessels in dog and monkey show an association between adrenergic varicosities and arterioles in bilaterally ganglion-ectomized animals. This adrenergic-vascular association was not seen in the rat. The results provide further evidence that central adrenergic innervation from the brain stem may control intracerebral blood flow independent of sympathetic influence. PMID:11370237

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

    PubMed Central

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

    2014-01-01

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

  7. Blood vessel remodeling in pig ovarian follicles during the periovulatory period: an immunohistochemistry and SEM-corrosion casting study

    PubMed Central

    Martelli, Alessandra; Palmerini, Maria Grazia; Russo, Valentina; Rinaldi, Carlo; Bernabò, Nicola; Di Giacinto, Oriana; Berardinelli, Paolo; Nottola, Stefania Annarita; Macchiarelli, Guido; Barboni, Barbara

    2009-01-01

    Background The present research aims to describe the process of vascular readjustment occurring in pig ovary during the periovulatory phase (from LH surge to ovulation) that drives the transformation of the follicle, a limited blood supplied structure, into the corpus luteum, a highly vascularised endocrine gland required to maintain high levels of progesterone in pregnancy. The swine model was chosen because it is characterized by a long periovulatory window (about 40–44 hrs-similar to human) that permits to recover follicles at a precise endocrinological timing. Methods By validated hormonal protocol (eCG+hCG), able to mimic the physiologic gonadotropin stimulation, preovulatory follicles (PreOFs, 60 h-eCG), follicles in the middle (early periovulatory follicles, EPerOFs, 18 h-hCG) or late (LPerOFs, 36 h-hCG) periovulatory phase were isolated from prepubertal gilts. To understand the angiogenic process, morphological/morphometrical analyses were performed by combining immunohistochemistry (IHC) and SEM of vascular corrosion casts (VCC) techniques. Results PreOFs showed a vascular plexus with proliferating endothelial cells (EPI). This plexus was characterized by a dense inner capillary network, with angiogenic figures, connected to the outer network by anastomotic vessels (arterioles and venules of the middle network). EPerOFs decreased their EPI, blood vessel extension in the outer network, and evidenced a reduced compactness of blood vessels. In LPerOFs, a rapid neovascularization was associated to an intensive tissue remodeling: the follicle acquired an undulated aspect presenting arterioles/venules near the basal membrane, increased vascular extension by EPI, sprouting and non-sprouting angiogenesis. The analysis of vascular geometric relations and branching angles evidenced similar values at all stages. Conclusion These data allow us to hypothesize that EPerOFs are in a quiescent status. LPerOFs represent the "metamorphic" follicles that rapidly turn

  8. Pulsatile magneto-hydrodynamic blood flows through porous blood vessels using a third grade non-Newtonian fluids model.

    PubMed

    Akbarzadeh, Pooria

    2016-04-01

    In this paper, the unsteady pulsatile magneto-hydrodynamic blood flows through porous arteries concerning the influence of externally imposed periodic body acceleration and a periodic pressure gradient are numerically simulated. Blood is taken into account as the third-grade non-Newtonian fluid. Besides the numerical solution, for small Womersley parameter (such as blood flow through arterioles and capillaries), the analytical perturbation method is used to solve the nonlinear governing equations. Consequently, analytical expressions for the velocity profile, wall shear stress, and blood flow rate are obtained. Excellent agreement between the analytical and numerical predictions is evident. Also, the effects of body acceleration, magnetic field, third-grade non-Newtonian parameter, pressure gradient, and porosity on the flow behaviors are examined. Some important conclusions are that, when the Womersley parameter is low, viscous forces tend to dominate the flow, velocity profiles are parabolic in shape, and the center-line velocity oscillates in phase with the driving pressure gradient. In addition, by increasing the pressure gradient, the mean value of the velocity profile increases and the amplitude of the velocity remains constant. Also, when non-Newtonian effect increases, the amplitude of the velocity profile. PMID:26792174

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

    ERIC Educational Resources Information Center

    Škorjanc, Aleš; Belušic, Gregor

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Critser, Paul J.; Yoder, Mervin C.

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

  11. A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels.

    PubMed

    Wang, Tong; Rongin, Uwitije; Xing, Zhongwen

    2016-01-01

    Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensional motions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow. PMID:26830454

  12. A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels

    PubMed Central

    Wang, Tong; Rongin, Uwitije; Xing, Zhongwen

    2016-01-01

    Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensional motions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow. PMID:26830454

  13. A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Rongin, Uwitije; Xing, Zhongwen

    2016-02-01

    Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensional motions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow.

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

    PubMed Central

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

    2015-01-01

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

  15. "Overshoot" of O₂ is required to maintain baseline tissue oxygenation at locations distal to blood vessels.

    PubMed

    Devor, Anna; Sakadzic, Sava; Saisan, Payam A; Yaseen, Mohammad A; Roussakis, Emmanuel; Srinivasan, Vivek J; Vinogradov, Sergei A; Rosen, Bruce R; Buxton, Richard B; Dale, Anders M; Boas, David A

    2011-09-21

    In vivo imaging of cerebral tissue oxygenation is important in defining healthy physiology and pathological departures associated with cerebral disease. We used a recently developed two-photon microscopy method, based on a novel phosphorescent nanoprobe, to image tissue oxygenation in the rat primary sensory cortex in response to sensory stimulation. Our measurements showed that a stimulus-evoked increase in tissue pO₂ depended on the baseline pO₂ level. In particular, during sustained stimulation, the steady-state pO₂ at low-baseline locations remained at the baseline, despite large pO₂ increases elsewhere. In contrast to the steady state, where pO₂ never decreased below the baseline, transient decreases occurred during the "initial dip" and "poststimulus undershoot." These results suggest that the increase in blood oxygenation during the hemodynamic response, which has been perceived as a paradox, may serve to prevent a sustained oxygenation drop at tissue locations that are remote from the vascular feeding sources. PMID:21940458

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

    PubMed

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

    2011-09-01

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

  17. Tenascin-W is a specific marker of glioma-associated blood vessels and stimulates angiogenesis in vitro

    PubMed Central

    Martina, Enrico; Degen, Martin; Rüegg, Curzio; Merlo, Adrian; Lino, Maddalena M.; Chiquet-Ehrismann, Ruth; Brellier, Florence

    2010-01-01

    The microenvironment hosting a tumor actively participates in regulating tumor cell proliferation, migration, and invasion. Among the extracellular matrix proteins enriched in the stroma of carcinomas are the tenascin family members tenascin-C and tenascin-W. Whereas tenascin-C overexpression in gliomas is known to correlate with poor prognosis, the status of tenascin-W in brain tumors has not been investigated so far. In the present study, we analyzed protein levels of tenascin-W in 38 human gliomas and found expression of tenascin-W in 80% of the tumor samples, whereas no tenascin-W could be detected in control, nontumoral brain tissues. Double immunohistochemical staining of tenascin-W and von Willebrand factor revealed that tenascin-W is localized around blood vessels, exclusively in tumor samples. In vitro, the presence of tenascin-W increased the proportion of elongated human umbilical vein endothelial cells (HUVECs) and augmented the mean speed of cell migration. Furthermore, tenascin-W triggered sprouting of HUVEC spheroids to a similar extent as the proangiogenic factor tenascin-C. In conclusion, our study identifies tenascin-W as a candidate biomarker for brain tumor angiogenesis that could be used as a molecular target for therapy irrespective of the glioma subtype.—Martina, E., Degen, M., Rüegg, C., Merlo, A., Lino, M. M., Chiquet-Ehrismann, R., Brellier, F. Tenascin-W is a specific marker of glioma-associated blood vessels and stimulates angiogenesis in vitro. PMID:19884327

  18. Erythropoietin-enhanced endothelial progenitor cell recruitment in peripheral blood and renal vessels during experimental acute kidney injury in rats.

    PubMed

    Cakiroglu, Figen; Enders-Comberg, Sora Maria; Pagel, Horst; Rohwedel, Jürgen; Lehnert, Hendrik; Kramer, Jan

    2016-03-01

    Beneficial effects of erythropoietin (EPO) have been reported in acute kidney injury (AKI) when administered prior to induction of AKI. We studied the effects of EPO administration on renal function shortly after ischemic AKI. For this purpose, rats were subjected to renal ischemia for 30 min and EPO was administered at a concentration of 500 U/kg either i.v. as a single shot directly after ischemia or with an additional i.p. dose until 3 days after surgery. The results were compared with AKI rats without EPO application and a sham-operated group. Renal function was assessed by measurement of serum biochemical markers, histological grading, and using an isolated perfused kidney (IPK) model. Furthermore, we performed flow cytometry to analyze the concentration of endothelial progenitor cells (EPCs) in the peripheral blood and renal vessels. Following EPO application, there was only a statistically non-significant tendency of serum creatinine and urea to improve, particularly after daily EPO application. Renal vascular resistance and the renal perfusion rate were not significantly altered. In the histological analysis, acute tubular necrosis was only marginally ameliorated following EPO administration. In summary, we could not demonstrate a significant improvement in renal function when EPO was applied after AKI. Interestingly, however, EPO treatment resulted in a highly significant increase in CD133- and CD34-positive EPC both in the peripheral blood and renal vessels. PMID:26616141

  19. Forkhead Box M1 Transcriptional Factor is Required for Smooth Muscle Cells during Embryonic Development of Blood Vessels and Esophagus

    PubMed Central

    Ustiyan, Vladimir; Wang, I-Ching; Ren, Xiaomeng; Zhang, Yufang; Snyder, Jonathan; Xu, Yan; Wert, Susan E.; Lessard, James L.; Kalin, Tanya V.; Kalinichenko, Vladimir V.

    2009-01-01

    The Forkhead Box m1 (Foxm1 or Foxm1b) transcription factor (previously called HFH-11B, Trident, Win, or MPP2) is expressed in a variety of tissues during embryogenesis, including vascular, airway and intestinal smooth muscle cells (SMC). Although global deletion of Foxm1 in Foxm1−/− mice is lethal in the embryonic period due to multiple abnormalities in the liver, heart and lung, the specific role of Foxm1 in SMC remains unknown. In the present study, Foxm1 was deleted conditionally in the developing SMC (smFoxm1−/− mice). The majority of smFoxm1−/− mice died immediately after birth due to severe pulmonary hemorrhage, and structural defects in arterial wall and esophagus. Although Foxm1 deletion did not influence SMC differentiation, decreased proliferation of SMC was found in smFoxm1−/− blood vessels and esophagus. Depletion of Foxm1 in cultured SMC caused G2 arrest and decreased numbers of cells undergoing mitosis. Foxm1-deficiency in vitro and in vivo was associated with reduced expression of cell cycle regulatory genes, including cyclin B1, Cdk1-activator Cdc25b phosphatase, Polo-like 1 and JNK1 kinases, and cMyc transcription factor. Foxm1 is critical for proliferation of smooth muscle cells and is required for proper embryonic development of blood vessels and esophagus. PMID:19835856

  20. Bone morphogenetic protein signaling promotes morphogenesis of blood vessels, wound epidermis, and actinotrichia during fin regeneration in zebrafish.

    PubMed

    Thorimbert, Valentine; König, Désirée; Marro, Jan; Ruggiero, Florence; Jaźwińska, Anna

    2015-10-01

    Zebrafish fin regeneration involves initial formation of the wound epidermis and the blastema, followed by tissue morphogenesis. The mechanisms coordinating differentiation of distinct tissues of the regenerate are poorly understood. Here, we applied pharmacologic and transgenic approaches to address the role of bone morphogenetic protein (BMP) signaling during fin restoration. To map the BMP transcriptional activity, we analyzed the expression of the evolutionarily conserved direct phospho-Smad1 target gene, id1, and its homologs id2a and id3. This analysis revealed the BMP activity in the distal blastema, wound epidermis, osteoblasts, and blood vessels of the regenerate. Blocking the BMP function with a selective chemical inhibitor of BMP type I receptors, DMH1, suppressed id1 and id3 expression and arrested regeneration after blastema formation. We identified several previously uncharacterized functions of BMP during fin regeneration. Specifically, BMP signaling is required for remodeling of plexus into structured blood vessels in the rapidly growing regenerate. It organizes the wound epithelium by triggering wnt5b expression and promoting Collagen XIV-A deposition into the basement membrane. BMP represents the first known signaling that induces actinotrichia formation in the regenerate. Our data reveal a multifaceted role of BMP for coordinated morphogenesis of distinct tissues during regeneration of a complex vertebrate appendage. PMID:26148971

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2013-01-01

    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

  3. Sonic hedgehog is required for the assembly and remodeling of branchial arch blood vessels.

    PubMed

    Kolesová, Hana; Roelink, Henk; Grim, Milos

    2008-07-01

    Sonic hedgehog (Shh) is a morphogen involved in many developmental processes. Injection of cells (5E1) that produce a Shh-blocking antibody causes an attenuation of the Shh response, and this causes vascular malformations and impaired remodeling characterized by hemorrhages and protrusions of the anterior cardinal vein and outflow tract, delayed fusion of the dorsal aortae, impaired branching of the internal carotid artery, and delayed remodeling of the aortic arches. Distribution of smooth muscle cells in the vessel wall is unchanged. In 5E1-injected embryos, we also observed impaired assembly of endothelial cells into vascular tubes, particularly in the sixth branchial arch, around the anterior cardinal vein and around the dorsal aorta. In 5E1-treated embryos, increased numbers of macrophage-like cells, apoptotic cells, and a decreased level of proliferation were observed in head mesenchyme. Together, these observations show that Shh signaling is required at multiple stages for proper vessel formation and remodeling. PMID:18570256

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

    NASA Technical Reports Server (NTRS)

    Palazhchenko, E. F.

    1979-01-01

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

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

    PubMed

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

    2004-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

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

    NASA Technical Reports Server (NTRS)

    Kasimtsev, A. A.

    1980-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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 800μm wide by ~ 3mm deep B-Frame slice with a lateral resolution of 10μm and a depth resolution of 7μm. 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.

  9. The blood vessel system in the periodontal ligament of the equine cheek teeth--part I: The spatial arrangement in layers.

    PubMed

    Masset, Alexandra; Staszyk, Carsten; Gasse, Hagen

    2006-11-01

    Corrosion casts of blood vessels in the periodontium of cheek teeth from eight horses were observed three-dimensionally with a dissection microscope. Selected specimens were examined in a scanning electron microscope. Periodontal blood vessels communicated with those from the gingiva, the alveolar bone, and the apical region. In the upper jaw, there were anastomoses with the blood vessels of the mucosa of the maxillary sinus. The periodontal vascular system was organized in two or three layers. The peripheral layer was mainly composed of large venules, the inner one consisted of capillaries. In the intermediate layer, blood vessels were post-capillary venules. This layer was developed only in horses under 10 years of age. In all layers the vascular orientation was mainly occluso-apical, this was defined as the standard pattern. There were many variations displayed in different courses of certain blood vessels. The vascular organization is discussed with regard to the specialized functions of the periodontal ligament (PDL). The wide vessels of the outer layer are thought to play a mechanical role as part of a shock absorbing system. The capillaries of the inner layer meet nutritional requirements. The disappearance of the intermediate layer in horses older than 10 years is taken as an adaptation to the remodelling of the PDL. Modifications in the standard pattern of vascular arrangements are also interpreted as adaptations to life-long changes in the periodontal space. Anastomoses between the periodontal vasculature and the blood vessels of the maxillary sinus indicate that periodontal disease may be transferred into the sinus. PMID:17140145

  10. C-reactive protein and chitinase 3-like protein 1 as biomarkers of spatial redistribution of retinal blood vessels on digital retinal photography in patients with diabetic retinopathy

    PubMed Central

    Cekić, Sonja; Cvetković, Tatjana; Jovanović, Ivan; Jovanović, Predrag; Pešić, Milica; Babić, Gordana Stanković; Milenković, Svetislav; Risimić, Dijana

    2014-01-01

    The aim of the study was to investigate the correlation between the levels of C-reactive protein (CRP) and chitinase 3-like protein 1 (YKL-40) in blood samples with morpohometric parameters of retinal blood vessels in patients with diabetic retinopathy. Blood laboratory examination of 90 patients included the measurement of glycemia, HbA1C, total cholesterol, LDL-C, HDL-C, triglycerides and CRP. Levels of YKL-40 were detected and measured in serum by ELISA (Micro VueYKL-40 EIA Kit, Quidel Corporation, San Diego, USA). YKL-40 correlated positively with diameter and negatively with number of retinal blood vessels. The average number of the blood vessels per retinal zone was significantly higher in the group of patients with mild non-proliferative diabetic retinopathy than in the group with severe form in the optic disc and all five retinal zones. The average outer diameter of the evaluated retinal zones and optic disc vessels was significantly higher in the group with severe compared to the group with mild diabetic retinopathy. Morphological analysis of the retinal vessels on digital fundus photography and correlation with YKL-40 may be valuable for the follow-up of diabetic retinopathy. PMID:25172979

  11. Unsteady non-Newtonian blood flow through a tapered overlapping stenosed catheterized vessel.

    PubMed

    Ali, N; Zaman, A; Sajid, M; Nieto, J J; Torres, A

    2015-11-01

    The unsteady flow characteristics of blood in a catheterized overlapping stenosed artery are analyzed in presence of body acceleration and magnetic field. The stenosed arterial segment is modeled as a rigid constricted tube. An improved shape of stenosis in the realm of the formulation of the arterial narrowing caused by atheroma is integrated in the present study. The catheter inside the artery is approximated by a thin rigid tube of small radius while the streaming blood in the artery is characterized by the Carreau model. Employing mild stenosis condition, the governing equation of the flow is derived which is then solving numerically using finite difference scheme. The variation of axial velocity, flow rate, resistance impendence and wall shear stress is shown graphically for various parameters of interest. The flow patterns illustrating the global behavior of blood are also presented. PMID:26361287

  12. In vivo μPIV measurements of blood velocity in small vessels of a rat model

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

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

  13. MR vascular fingerprinting: A new approach to compute cerebral blood volume, mean vessel radius, and oxygenation maps in the human brain.

    PubMed

    Christen, T; Pannetier, N A; Ni, W W; Qiu, D; Moseley, M E; Schuff, N; Zaharchuk, G

    2014-04-01

    In the present study, we describe a fingerprinting approach to analyze the time evolution of the MR signal and retrieve quantitative information about the microvascular network. We used a Gradient Echo Sampling of the Free Induction Decay and Spin Echo (GESFIDE) sequence and defined a fingerprint as the ratio of signals acquired pre- and post-injection of an iron-based contrast agent. We then simulated the same experiment with an advanced numerical tool that takes a virtual voxel containing blood vessels as input, then computes microscopic magnetic fields and water diffusion effects, and eventually derives the expected MR signal evolution. The parameter inputs of the simulations (cerebral blood volume [CBV], mean vessel radius [R], and blood oxygen saturation [SO2]) were varied to obtain a dictionary of all possible signal evolutions. The best fit between the observed fingerprint and the dictionary was then determined by using least square minimization. This approach was evaluated in 5 normal subjects and the results were compared to those obtained by using more conventional MR methods, steady-state contrast imaging for CBV and R and a global measure of oxygenation obtained from the superior sagittal sinus for SO2. The fingerprinting method enabled the creation of high-resolution parametric maps of the microvascular network showing expected contrast and fine details. Numerical values in gray matter (CBV=3.1±0.7%, R=12.6±2.4μm, SO2=59.5±4.7%) are consistent with literature reports and correlated with conventional MR approaches. SO2 values in white matter (53.0±4.0%) were slightly lower than expected. Numerous improvements can easily be made and the method should be useful to study brain pathologies. PMID:24321559

  14. Blood-Based Biomarkers for Metabolic Syndrome.

    PubMed

    O'Neill, Sadhbh; Bohl, Mette; Gregersen, Soren; Hermansen, Kjeld; O'Driscoll, Lorraine

    2016-06-01

    Metabolic syndrome (MetS) is a constellation of factors increasing the risk of type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and cancer. MetS diagnosis is cumbersome and the precise diagnosis differs throughout the world. Efforts are underway to find MetS biomarkers that could all be analysed in a single blood sample. Here we review recent advances, including progress on circulating exosomes and microvesicles and their molecular contents, as well as DNA, RNAs, and proteins taken directly from blood samples. While additional research is now warranted to advance upon these findings, there is reason for optimising that such blood-based entities will be beneficial for MetS diagnosis and will help reduce risk of T2DM, CVD, and cancers, contributing both societal and economic benefit. PMID:27150849

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

    PubMed

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

    2014-01-01

    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-β-CD (#1), α-CD (#2) and γ-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 20μg/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±0.3μm. 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

  16. Tumor-Induced Local and Systemic Impact on Blood Vessel Function

    PubMed Central

    Cedervall, J.; Dimberg, A.; Olsson, A-K.

    2015-01-01

    Endothelial dysfunction plays a role in several processes that contribute to cancer-associated mortality. The vessel wall serves as a barrier for metastatic tumor cells, and the integrity and activation status of the endothelium serves as an important defense mechanism against metastasis. In addition, leukocytes, such as cytotoxic T-cells, have to travel across the vessel wall to enter the tumor tissue where they contribute to killing of cancer cells. Tumor cells can alter the characteristics of the endothelium by recruitment of leukocytes such as neutrophils and macrophages, which further stimulate inflammation and promote tumorigenesis. Recent findings also suggest that leukocyte-mediated effects on vascular function are not limited to the primary tumor or tissues that represent metastatic sites. Peripheral organs, such as kidney and heart, also display impaired vascular function in tumor-bearing individuals, potentially contributing to organ failure. Here, we discuss how vascular function is altered in malignant tissue and distant organs in individuals with cancer and how leukocytes function as potent mediators of these tumor-induced effects. PMID:26770016

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

    PubMed Central

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

    2013-01-01

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

  18. Vascular endothelial growth factor receptor expression during embryogenesis and tissue repair suggests a role in endothelial differentiation and blood vessel growth.

    PubMed Central

    Peters, K G; De Vries, C; Williams, L T

    1993-01-01

    Vascular endothelial growth factor (VEGF) is a polypeptide mitogen that stimulates the growth of endothelial cells in vitro and promotes the growth of blood vessels in vivo. We have recently shown that the fms-like receptor tyrosine kinase (flt) is a receptor for VEGF. Here we used in situ hybridization to show that, in adult mouse tissues, the pattern of flt expression was consistent with localization in endothelium. We also show that flt was expressed in endothelium during neovascularization of healing skin wounds and during early vascular development in mouse embryos. Moreover, flt was expressed in populations of embryonic cells from which endothelium is derived such as early yolk sac mesenchyme. The expression of flt in the endothelium of both developing and mature blood vessels suggests that VEGF might regulate endothelial differentiation, blood vessel growth, and vascular repair. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7692439

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

    NASA Technical Reports Server (NTRS)

    Macovski, A.

    1978-01-01

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

  20. TRANSFUSIONS—Hazardous Acid-Base Changes with Citrated Blood

    PubMed Central

    Pedro, Jovita M. San; Iwai, Seizo; Hattori, Mitsuo; Leigh, M. Digby

    1962-01-01

    In a study of the acid-base changes in the blood of rabbits during and following transfusions of citrated blood and of heparinized blood, it was observed that, with citrated blood, pH decreased and carbon dioxide tensions rose. With heparinized blood, the acid-base balance was maintained within normal limits following transfusions. The potential hazards of rapid massive citrated blood transfusions in the anesthetized patient during operation must be kept in mind. PMID:14496706

  1. Combination probe for optically assisted ultrasonic velocity-change imaging aimed at detecting unstable blood vessel plaque

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Blood vessel plaque with a large lipid core is at risk of becoming thrombus and is likely to induce acute heart disease. To prevent this, it is necessary to determine not only the plaque's size but also its chemical composition. We, therefore, made the prototype of a combination probe to diagnose carotid artery plaque. It is used to differentiate propagation characteristics between light spectra and ultrasonic images. By propagating light and ultrasound along a common direction, it is possible to effectively warm the diagnosis domain. Moreover, the probe is thought to be compact and be easy to use for diagnosing human carotid artery plaque. We applied the combination probe to a carotid artery phantom with a lipid area and obtained an image of the ultrasonic velocity change in the fatty area.

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

    PubMed

    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

    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

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

    PubMed Central

    Raykin, Julia; Rachev, Alexander I.

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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.

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

    PubMed Central

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

    2012-01-01

    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

  6. Study of an adenosine A1 receptor agonist on trigeminally evoked dural blood vessel dilation in the anaesthetized rat.

    PubMed

    Honey, A C; Bland-Ward, P A; Connor, H E; Feniuk, W; Humphrey, P P A

    2002-05-01

    The purpose of this study was to use intravital microscopy to determine the effect of a selective adenosine A1 receptor agonist, GR79236 (1, 3 and 10 microg/kg i.v.), on neurogenic dural blood vessel dilation in anaesthetized rats. Vasodilation was evoked either by electrical stimulation of perivascular trigeminal nerves or by intravenous CGRP. GR79236 (1-10 microg/kg i.v.) caused a dose-dependent inhibition of neurogenic vasodilation, but had no significant effect on dural vasodilation caused by CGRP. GR79236 (1-3 microg/kg i.v.) had no effect on basal dural vessel diameter, but caused transient dose-dependant bradycardia and hypotension. Bradycardia was more prolonged following 10 microg/kg i.v. GR79236. Pre-treatment with the adenosine A1 receptor antagonist DPCPX (1 mg/kg i.v.) prevented the inhibitory effect of GR79236 (10 microg/kg i.v.) on neurogenic vasodilation as well as GR79236-induced bradycardia and hypotension. These data suggest that the inhibition of neurogenic vasodilation by GR79236 is mediated via the activation of prejunctional adenosine A1 receptors. Provided the systemic cardiovascular effects could be limited, such a mechanism may offer a novel approach to migraine therapy. PMID:12100087

  7. Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

    PubMed Central

    Huber, Birgit; Engelhardt, Sascha; Meyer, Wolfdietrich; Krüger, Hartmut; Wenz, Annika; Schönhaar, Veronika; Tovar, Günter E. M.; Kluger, Petra J.; Borchers, Kirsten

    2016-01-01

    Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA) for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM), biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors. PMID:27104576

  8. Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization.

    PubMed

    Huber, Birgit; Engelhardt, Sascha; Meyer, Wolfdietrich; Krüger, Hartmut; Wenz, Annika; Schönhaar, Veronika; Tovar, Günter E M; Kluger, Petra J; Borchers, Kirsten

    2016-01-01

    Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA) for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM), biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap(®) technology by the authors. PMID:27104576

  9. Vomiting blood

    MedlinePlus

    ... first part of the small intestine, or esophagus Blood clotting disorders Defects in the blood vessels of the ... as a complete blood count (CBC), blood chemistries, blood clotting tests, and liver function tests Esophagogastroduodenoscopy (EGD) (placing ...

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

    SciTech Connect

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

    2004-12-09

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

  11. Early Generation of New PrPSc on Blood Vessels after Brain Microinjection of Scrapie in Mice

    PubMed Central

    Striebel, James; Rangel, Alejandra; Phillips, Katie; Hughson, Andrew; Caughey, Byron; Race, Brent

    2015-01-01

    ABSTRACT Aggregation of misfolded host proteins in the central nervous system is believed to be important in the pathogenic process in several neurodegenerative diseases of humans, including prion diseases, Alzheimer’s disease, and Parkinson’s disease. In these diseases, protein misfolding and aggregation appear to expand through a process of seeded polymerization. Prion diseases occur in both humans and animals and are experimentally transmissible orally or by injection, thus providing a controllable model of other neurodegenerative protein misfolding diseases. In rodents and ruminants, prion disease has a slow course, lasting months to years. Although prion infectivity has been detected in brain tissue at 3 to 4 weeks postinfection (p.i.), the details of early prion replication in the brain are not well understood. Here we studied the localization and quantitation of PrPSc generation in vivo starting at 30 min postmicroinjection of scrapie into the brain. In C57BL mice at 3 days p.i., generation of new PrPSc was detected by immunohistochemistry and immunoblot assays, and at 7 days p.i., new generation was confirmed by real-time quaking-induced conversion assay. The main site of new PrPSc generation was near the outer basement membrane of small and medium blood vessels. The finding and localization of replication at this site so early after injection have not been reported previously. This predominantly perivascular location suggested that structural components of the blood vessel basement membrane or perivascular astrocytes might act as cofactors in the initial generation of PrPSc. The location of PrPSc replication at the basement membrane also implies a role for the brain interstitial fluid drainage in the early infection process. PMID:26396245

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

    PubMed Central

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

    2010-01-01

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

  13. Optical monitoring of complex dynamics of blood sedimentation and lymph flow in vessels

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.

    2004-05-01

    In this paper a few examples of the complex behavior of biological systems detected by optical techniques are described. All examples are related to cell suspensions behavior in in vitro and in vivo studies. In vitro studies performing investigation of a fine structure of blood sedimentation process and establishing nonlinear features of blood sedimentation as disease prognostic parameters are overviewed. Three optical techniques: OCT, CW laser beam transverse synchronized transillumination method and spatially-modulated laser beam transillumination method were considered. In blood sedimentation studied by OCT the regular or irregular oscillations of the RBC/plasma boundary were observed. The functional properties of erythrocytes in patients with coronary heart disease by mean of spatially-modulated laser beam transillumination method to reveal the stages of the acute coronary syndrome formation are discussed. The laser speckle and intravital TV-microscopic techniques applied to in vivo studies of lymph flow in microvessels are overviewed. The hypothesis on the alternating-translation (shuttle-stream) character of lymph flow is discussed.

  14. The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels.

    PubMed

    Alencastre, I S; Sousa, D M; Alves, C J; Leitão, L; Neto, E; Aguiar, P; Lamghari, M

    2016-01-01

    In the last decade, nanobiotechnology research has emerged as a revolutionising new approach to the 21st century pharmaceutical challenges, offering valuable gains in a vast set of biomedical applications. In the field of bone tissue engineering, a broad range of nanotechnology-based delivery systems have been researched and the most recent developments in high-throughput technology and in silico approaches are creating very high expectations. This review presents a comprehensive overview of the emergent nanotechnology-based materials, processing techniques and research strategies for the delivery of pharmaceutics to bone including the materials general characteristics and the available drug delivery systems to distribute agents systemically or locally. Complementary to what was stated above, it also reviews the latest high-throughput processing techniques and the existent in silico tools (mathematical and computational models) used to help on the design of delivery systems. PMID:27232664

  15. Computer simulation of MHD blood conveying gold nanoparticles as a third grade non-Newtonian nanofluid in a hollow porous vessel.

    PubMed

    Hatami, M; Hatami, J; Ganji, D D

    2014-02-01

    In this paper, heat transfer and flow analysis for a non-Newtonian third grade nanofluid flow in porous medium of a hollow vessel in presence of magnetic field are simulated analytically and numerically. Blood is considered as the base third grade non-Newtonian fluid and gold (Au) as nanoparticles are added to it. The viscosity of nanofluid is considered a function of temperature as Vogel's model. Least Square Method (LSM), Galerkin method (GM) and fourth-order Runge-Kutta numerical method (NUM) are used to solve the present problem. The influences of the some physical parameters such as Brownian motion and thermophoresis parameters on non-dimensional velocity and temperature profiles are considered. The results show that increasing the thermophoresis parameter (N(t)) caused an increase in temperature values in whole domain and an increase in nanoparticles concentration just near th