The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform

Kunio Ishii - One of the best experts on this subject based on the ideXlab platform.

  • Vasodilator effects of ibudilast on retinal Blood Vessels in anesthetized rats.
    Biological & pharmaceutical bulletin, 2009
    Co-Authors: Masahiro Noguchi, Asami Mori, Tsutomu Nakahara, Kenji Sakamoto, Kunio Ishii
    Abstract:

    Ibudilast (3-isobutyryl-2-isopropylpyrazolo[1,5-α]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.

  • Vasodilator effect of nicorandil on retinal Blood Vessels in rats
    Naunyn-Schmiedeberg's Archives of Pharmacology, 2007
    Co-Authors: Naoto Ogawa, Sokichi Kametaka, Maki Saito, Asami Mori, Tsutomu Nakahara, Kenji Sakamoto, Kunio Ishii
    Abstract:

    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 μg 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 μg 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 μg 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.

Vijay M. Mane - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of algorithms for segmentation of retinal Blood Vessels
    2015 International Conference on Pervasive Computing (ICPC), 2015
    Co-Authors: Ramish B. Kawadiwale, Vijay M. Mane
    Abstract:

    Assessment of retinal Blood Vessels plays crucial role in detection of many eye diseases. Extraction of Blood Vessels using image processing algorithms does the task of image registration. Thus Retinal Blood Vessels extraction is very important task. In this paper, we propose a modified approach for segmentation of Blood Vessels using matched filtering using two different values of variance parameter. Evaluation of other novel approaches for segmentation of retinal Blood Vessels is carried out and compared with proposed system. In first stage of algorithm, preprocessing methods are employed for enhancement of image quality and removal of noise. In second stage, classical matched filtering, proposed modified matched filtering, second derivative of Gaussian function filtering, K-means clustering and Fuzzy C-means clustering methods are used for Blood Vessels enhancement. Local entropy thresholding and length filtering is used for final segmentation of Blood Vessels in third stage. An automated system thus developed using each of algorithms stated earlier is tested on set of 40 ocular fundus images from DRIVE database and evaluated for sensitivity, specificity and accuracy. Sensitivity, specificity and accuracy of proposed method are found to be highest and equal to 80.63%, 97.16% and 96.84% respectively.

G. Jyothirmai - One of the best experts on this subject based on the ideXlab platform.

  • Automated Segmentation of Retinal Blood Vessels
    International Journal of Research, 2017
    Co-Authors: V. R. Jahnavi, K. Pavani, B. Savithri, G. Jyothirmai
    Abstract:

    Digital image processing and the image analysis technology based on the advances in microelectronics and computer have many applications in biology. In clinical ophthalmology, study of Blood Vessels in retina is important for detection of the diseases.  Diabetic retinopathy is one of the diseases which damages the retina and leads to blindness. Manual diagnosis of analyzing images from a patient with Diabetic Retinopathy increases the time. Automatic segmentation of retinal Blood Vessels could save workload of the ophthalmologists and may assist in characterizing the defected lesions and to identify false positives with high accuracy. The proposed algorithm uses optimized Gabor filter with local entropy thresholding. The Blood vessel detection and segmentation is important for diabetic retinopathy diagnosis at earlier stage. The proposed method detects Blood Vessels with higher accuracy and sensitivity in the retinal images. The DRIVE database has been used to enable comparative studies on segmentation of Blood Vessels in retinal images.

Jing Yu - One of the best experts on this subject based on the ideXlab platform.

  • Hormonal effects on Blood Vessels
    Hypertension Research, 2012
    Co-Authors: Masahiro Akishita, Jing Yu
    Abstract:

    The incidence of cardiovascular disease (CVD) is lower in younger women than in men of the same age, but it increases after menopause, implicating the atheroprotective action of endogenous estrogen. Although observational studies have suggested the efficacy of estrogen therapy in postmenopausal women, placebo-controlled, randomized trials, such as the Women's Health Initiative, have not confirmed effects of estrogen therapy on CVD. Conversely, basic, experimental research has progressed and provided mechanistic insight into estrogen's action on Blood Vessels. By contrast, the vascular effects of androgens remain poorly understood and have been controversial for a long time. In recent years, an increasing body of evidence has suggested that androgens may exert protective effects against the development of atherosclerosis, at least in elderly men. Epidemiological studies have shown that the incidence of and mortality due to CVD were increased in elderly men with low testosterone levels, although the efficacy of androgen therapy remains unknown. Furthermore, recent experimental studies have demonstrated the direct action of androgens on the vasculature. In this review, we illustrate the effects of sex steroids on the cardiovascular system, focusing on the action of testosterone on the Blood Vessels.

Donald M. Mcdonald - One of the best experts on this subject based on the ideXlab platform.

  • Dynamics of Airway Blood Vessels and Lymphatics
    2012
    Co-Authors: Donald M. Mcdonald, Li-chin Yao, Peter Baluk
    Abstract:

    Blood Vessels and lymphatic Vessels in the respiratory tract play key roles in inflammation. By undergoing adaptive remodeling and growth, Blood Vessels undergo changes that enable the extravasation of plasma and leukocytes into inflamed tissues, and lymphatic Vessels adjust to the increased fluid clearance and cell traffic involved in immune responses. Blood Vessels and lymphatics in adult airways are strikingly different from those of late-stage embryos. Before birth, Blood Vessels in mouse airways make up a primitive plexus similar to that of the yolk sac. This plexus undergoes rapid and extensive remodeling at birth. In the early neonatal period, parts of the plexus regress. Capillaries then rapidly regrow, and with arterioles and venules form the characteristic adult vascular pattern. Lymphatic Vessels of the airways also undergo rapid changes around birth, when lymphatic endothelial cells develop button-like intercellular junctions specialized for efficient fluid uptake. Among the mechanisms that un...

  • dynamics of airway Blood Vessels and lymphatics lessons from development and inflammation
    Proceedings of the American Thoracic Society, 2011
    Co-Authors: Donald M. Mcdonald, Li-chin Yao, Peter Baluk
    Abstract:

    Blood Vessels and lymphatic Vessels in the respiratory tract play key roles in inflammation. By undergoing adaptive remodeling and growth, Blood Vessels undergo changes that enable the extravasation of plasma and leukocytes into inflamed tissues, and lymphatic Vessels adjust to the increased fluid clearance and cell traffic involved in immune responses. Blood Vessels and lymphatics in adult airways are strikingly different from those of late-stage embryos. Before birth, Blood Vessels in mouse airways make up a primitive plexus similar to that of the yolk sac. This plexus undergoes rapid and extensive remodeling at birth. In the early neonatal period, parts of the plexus regress. Capillaries then rapidly regrow, and with arterioles and venules form the characteristic adult vascular pattern. Lymphatic Vessels of the airways also undergo rapid changes around birth, when lymphatic endothelial cells develop button-like intercellular junctions specialized for efficient fluid uptake. Among the mechanisms that underlie the onset of rapid vascular remodeling at birth, changes in tissue oxygen tension and mechanical forces associated with breathing are likely to be involved, along with growth factors that promote the growth and maturation of Blood Vessels and lymphatics. Whatever the mechanisms, the dynamic nature of airway Blood Vessels and lymphatics during perinatal development foretells the extraordinary vascular plasticity found in many diseases.

  • Antiangiogenic Therapy Decreases Integrin Expression in Normalized Tumor Blood Vessels
    Cancer Research, 2006
    Co-Authors: Michael G Ozawa, Amanda S. Varner, Ian Kasman, Yvan Chanthery, Renata Pasqualini, Wadih Arap, Donald M. Mcdonald
    Abstract:

    Tumor Blood Vessels normalized by antiangiogenic therapy may provide improved delivery of chemotherapeutic agents during a window of time but it is unknown how protein expression in tumor vascular endothelial cells changes. We evaluated the distribution of RGD-4C phage, which binds αvβ3, αvβ5, and α5β1 integrins on tumor Blood Vessels before and after antiangiogenic therapy. Unlike the control phage, fd-tet, RGD-4C phage homed to vascular endothelial cells in spontaneous tumors in RIP-Tag2 transgenic mice in a dose-dependent fashion. The distribution of phage was similar to αvβ3 and α5β1 integrin expression. Blood Vessels that survived treatment with AG-013736, a small molecule inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptors, had only 4% as much binding of RGD-4C phage compared with Vessels in untreated tumors. Cellular distribution of RGD-4C phage in surviving tumor Vessels matched the α5β1 integrin expression. The reduction in integrin expression on tumor Vessels after antiangiogenic therapy raises the possibility that integrin-targeted delivery of diagnostics or therapeutics may be compromised. Efficacious delivery of drugs may benefit from identification by in vivo phage display of targeting peptides that bind to tumor Blood Vessels normalized by antiangiogenic agents. (Cancer Res 2006; 66(5): 2639-49)