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Sample records for vascular channels resulting

  1. Connections matter: channeled hydrogels to improve vascularization

    Directory of Open Access Journals (Sweden)

    Severin eMuehleder

    2014-11-01

    Full Text Available The use of cell-laden hydrogels to engineer soft tissue has been emerging within the past years. Despite several newly developed and sophisticated techniques to encapsulate different cell types the importance of vascularization of the engineered constructs is often underestimated. As a result, cell death within a construct leads to impaired function and inclusion of the implant. Here, we discuss the fabrication of hollow channels within hydrogels as a promising strategy to facilitate vascularization. Furthermore, we present an overview on the feasible use of removable spacers, 3D laser- and planar processing strategies to create channels within hydrogels. The implementation of these structures promotes control over cell distribution and increases oxygen transport and nutrient supply in vitro. However, many studies lack the use of endothelial cells in their approaches leaving out an important factor to enhance vessel ingrowth and anastomosis formation upon implantation. In addition, the adequate endothelial cell type needs to be considered to make these approaches bridge the gap to in vivo applications.

  2. Connections matter: channeled hydrogels to improve vascularization.

    Science.gov (United States)

    Muehleder, Severin; Ovsianikov, Aleksandr; Zipperle, Johannes; Redl, Heinz; Holnthoner, Wolfgang

    2014-01-01

    The use of cell-laden hydrogels to engineer soft tissue has been emerging within the past years. Despite, several newly developed and sophisticated techniques to encapsulate different cell types the importance of vascularization of the engineered constructs is often underestimated. As a result, cell death within a construct leads to impaired function and inclusion of the implant. Here, we discuss the fabrication of hollow channels within hydrogels as a promising strategy to facilitate vascularization. Furthermore, we present an overview on the feasible use of removable spacers, 3D laser-, and planar processing strategies to create channels within hydrogels. The implementation of these structures promotes control over cell distribution and increases oxygen transport and nutrient supply in vitro. However, many studies lack the use of endothelial cells in their approaches leaving out an important factor to enhance vessel ingrowth and anastomosis formation upon implantation. In addition, the adequate endothelial cell type needs to be considered to make these approaches bridge the gap to in vivo applications.

  3. Role of renal vascular potassium channels in physiology and pathophysiology

    DEFF Research Database (Denmark)

    Salomonsson, Max; Brasen, Jens Christian; Sorensen, Charlotte Mehlin

    2017-01-01

    The control of renal vascular tone is important for the regulation of salt and water balance, blood pressure and the protection against damaging elevated glomerular pressure. The K+ conductance is a major factor in the regulation of the membrane potential (Vm ) in vascular smooth muscle (VSMC...... the ambiguous in vitro and in vivo results. We discuss the role of single types of K+ channels and the integrated function of several classes. We also deal with the possible role of renal vascular K+ channels in the pathophysiology of hypertension, diabetes mellitus and sepsis. This article is protected...

  4. Role of vascular potassium channels in the regulation of renal hemodynamics

    DEFF Research Database (Denmark)

    Sørensen, Charlotte Mehlin; Braunstein, Thomas Hartig; von Holstein-Rathlou, Niels-Henrik

    2012-01-01

    of one or more classes of K+ channels will lead to a change in hemodynamic resistance and therefore of renal blood flow and glomerular filtration pressure. Through these effects, the activity of renal vascular K+ channels influences renal salt and water excretion, fluid homeostasis, and ultimately blood...... pressure. Four main classes of K+ channels [calcium activated (KCa), inward rectifier (Kir), voltage activated (KV), and ATP sensitive (KATP)] are found in the renal vasculature. Several in vitro experiments have suggested a role for individual classes of K+ channels in the regulation of renal vascular...... function. Results from in vivo experiments are sparse. We discuss the role of the different classes of renal vascular K+ channels and their possible role in the integrated function of the renal microvasculature. Since several pathological conditions, among them hypertension, are associated with alterations...

  5. Computer tomography valorization of the vascular lingual channels in the jaw

    International Nuclear Information System (INIS)

    Costantino, Sebastian; Capiel, Carlos h; Bouzas, Carlos; Vuotto, Miguel; Ferrari, Daniela; Bazzano, Sebastian

    2006-01-01

    Purpose: To determine the frequency, location and position of vascular lingual channels of jaw by dental CT and classifying them based on its location. Material and methods: Dental CT of 100 consecutive patients were reevaluated as previous evaluation to the positioning of dental implants. They are classified by linking their location on the jaw with the number of tooth present or absent in that area. Results: All patients had at least one lingual vascular channel in the jaw; 36 patients presented two channels, eight patients presented three and a patient presented four. The more frequent location was between the sectors of the pieces 31 and 41. Sixteen patients showed two channels (superior and inferior) in that location. The second location by frequency was between pieces 32 and 33 (nine patients). The average distance between the lingual surface of the alveolar rim and the vascular channels was of 16 mm. Conclusion: the dental CT is an excellent method for the identification of the vascular lingual channels by its multiplanar capacity and appropriate image resolution. The characterization and classification of these conduits by a method of easy reading for the radiologists and the dentists assure a correct pre surgical valuation avoiding hemorrhages during the jaw perforation in the positioning of dental implants. (author) [es

  6. An aberrant vascular channel in the petrous bone: persistent lateral capital vein?

    International Nuclear Information System (INIS)

    Hermans, Robert; Rensburg, Leon J. van

    2009-01-01

    An aberrant channel was identified on CT in the petrous bone in four patients presenting with unrelated otological symptoms. These channels occurred unilaterally in each case. In two patients, the channel was seen to run between the sigmoid sinus sulcus and the superior petrosal sinus sulcus; in one of these patients, a vascular structure was identified within this channel on MRI, connecting the sigmoid sinus and the superior petrosal sinus. In the two other patients, an aberrant channel was seen between the superior petrosal sinus sulcus and the posterior genu of the facial nerve canal. There were no symptoms that could be attributed to the presence of these channels. We postulate that these aberrant vascular channels correspond to a persistent embryological vein, the lateral capital vein. (orig.)

  7. An aberrant vascular channel in the petrous bone: persistent lateral capital vein?

    Energy Technology Data Exchange (ETDEWEB)

    Hermans, Robert [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Rensburg, Leon J. van [University of the Western Cape, Department of Radiology and Diagnostics, Tygerberg (South Africa)

    2009-12-15

    An aberrant channel was identified on CT in the petrous bone in four patients presenting with unrelated otological symptoms. These channels occurred unilaterally in each case. In two patients, the channel was seen to run between the sigmoid sinus sulcus and the superior petrosal sinus sulcus; in one of these patients, a vascular structure was identified within this channel on MRI, connecting the sigmoid sinus and the superior petrosal sinus. In the two other patients, an aberrant channel was seen between the superior petrosal sinus sulcus and the posterior genu of the facial nerve canal. There were no symptoms that could be attributed to the presence of these channels. We postulate that these aberrant vascular channels correspond to a persistent embryological vein, the lateral capital vein. (orig.)

  8. The BK(Ca) channels deficiency as a possible reason for radiation-induced vascular hypercontractility.

    Science.gov (United States)

    Kyrychenko, Sergii; Tishkin, Sergey; Dosenko, Victor; Ivanova, Irina; Novokhatska, Tatiana; Soloviev, Anatoly

    2012-01-01

    It is likely that large-conductance Ca²⁺-activated K⁺ (BK(Ca)) channels channelopathy tightly involved in vascular malfunctions and arterial hypertension development. In the present study, we compared the results of siRNAs-induced α-BK(Ca) gene silencing and vascular abnormalities produced by whole-body ionized irradiation in rats. The experimental design comprised RT-PCR and patch clamp technique, thoracic aorta smooth muscle (SM) contractile recordings and arterial blood pressure (BP) measurements on the 30th day after whole body irradiation (6Gy) and following siRNAs KCNMA1 gene silencing in vivo. The expression profile of BK(Ca) mRNA transcripts in SM was significantly decreased in siRNAs-treated rats in a manner similar to irradiated SM. In contrast, the mRNA levels of K(v) and K(ATP) were significantly increased while L-type calcium channels mRNA transcripts demonstrated tendency to increment. The SMCs obtained from irradiated animals and after KCNMA1 gene silencing showed a significant decrease in total K⁺ current density amplitude. Paxilline (500 nM)-sensitive components of outward current were significantly decreased in both irradiated and gene silencing SMCs. KCNMA1 gene silencing increased SM sensitivity to norepinephrine while Ach-induced relaxation had decreased. The silencing of KCNMA1 had no significant effect on BP while radiation produced sustained arterial hypertension. Therefore, radiation alters the form and function of the BK(Ca) channel and this type of channelopathy may contribute to related vascular abnormalities. Nevertheless, it is unlikely that BK(Ca) can operate as a crucial factor for radiation-induced arterial hypertension. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. The SK3 channel promotes placental vascularization by enhancing secretion of angiogenic factors.

    Science.gov (United States)

    Rada, Cara C; Murray, Grace; England, Sarah K

    2014-11-15

    Proper placental perfusion is essential for fetal exchange of oxygen, nutrients, and waste with the maternal circulation. Impairment of uteroplacental vascular function can lead to pregnancy complications, including preeclampsia and intrauterine growth restriction (IUGR). Potassium channels have been recognized as regulators of vascular proliferation, angiogenesis, and secretion of vasoactive factors, and their dysfunction may underlie pregnancy-related vascular diseases. Overexpression of one channel in particular, the small-conductance calcium-activated potassium channel 3 (SK3), is known to increase vascularization in mice, and mice overexpressing the SK3 channel (SK3(T/T) mice) have a high rate of fetal demise and IUGR. Here, we show that overexpression of SK3 causes fetal loss through abnormal placental vascularization. We previously reported that, at pregnancy day 14, placentas isolated from SK3(T/T) mice are smaller than those obtained from wild-type mice. In this study, histological analysis reveals that SK3(T/-) placentas at this stage have abnormal placental morphology, and microcomputed tomography shows that these placentas have significantly larger and more blood vessels than those from wild-type mice. To identify the mechanism by which these vascularization defects occur, we measured levels of vascular endothelial growth factor (VEGF), placental growth factor, and the soluble form of VEGF receptor 1 (sFlt-1), which must be tightly regulated to ensure proper placental development. Our data reveal that overexpression of SK3 alters systemic and placental ratios of the angiogenic factor VEGF to antiangiogenic factor sFlt-1 throughout pregnancy. Additionally, we observe increased expression of hypoxia-inducing factor 2α in SK3(T/-) placentas. We conclude that the SK3 channel modulates placental vascular development and fetal health by altering VEGF signaling. Copyright © 2014 the American Physiological Society.

  10. Na+K+-ATPase activity and K+ channels differently contribute to vascular relaxation in male and female rats.

    Directory of Open Access Journals (Sweden)

    Fernanda Moura Vargas Dias

    Full Text Available Gender associated differences in vascular reactivity regulation might contribute to the low incidence of cardiovascular disease in women. Cardiovascular protection is suggested to depend on female sex hormones' effects on endothelial function and vascular tone regulation. We tested the hypothesis that potassium (K+ channels and Na+K+-ATPase may be involved in the gender-based vascular reactivity differences. Aortic rings from female and male rats were used to examine the involvement of K+ channels and Na+K+-ATPase in vascular reactivity. Acetylcholine (ACh-induced relaxation was analyzed in the presence of L-NAME (100 µM and the following K+ channels blockers: tetraethylammonium (TEA, 2 mM, 4-aminopyridine (4-AP, 5 mM, iberiotoxin (IbTX, 30 nM, apamin (0.5 µM and charybdotoxin (ChTX, 0.1 µM. The ACh-induced relaxation sensitivity was greater in the female group. After incubation with 4-AP the ACh-dependent relaxation was reduced in both groups. However, the dAUC was greater in males, suggesting that the voltage-dependent K+ channel (Kv participates more in males. Inhibition of the three types of Ca2+-activated K+ channels induced a greater reduction in Rmax in females than in males. The functional activity of the Na+K+-ATPase was evaluated by KCl-induced relaxation after L-NAME and OUA incubation. OUA reduced K+-induced relaxation in female and male groups, however, it was greater in males, suggesting a greater Na+K+-ATPase functional activity. L-NAME reduced K+-induced relaxation only in the female group, suggesting that nitric oxide (NO participates more in their functional Na+K+-ATPase activity. These results suggest that the K+ channels involved in the gender-based vascular relaxation differences are the large conductance Ca2+-activated K+ channels (BKCa in females and Kv in males and in the K+-induced relaxation and the Na+K+-ATPase vascular functional activity is greater in males.

  11. Vascular channels in metacarpophalangeal joints : a comparative histologic and high-resolution imaging study

    NARCIS (Netherlands)

    Scharmga, A.; Keller, K.K.; Peters, M.; van Tubergen, A.; van den Bergh, J.P.W.; van Rietbergen, B.; Weijers, R.; Loeffen, D.; Hauge, E.M.; Geusens, P.P.M.M.

    2017-01-01

    We evaluated whether cortical interruptions classified as vascular channel (VC) on high-resolution peripheral quantitative computed tomography (HR-pQCT) could be confirmed by histology. We subsequently evaluated the image characteristics of histologically identified VCs on matched single and

  12. Vascular ATP-sensitive potassium channels are over-expressed and partially regulated by nitric oxide in experimental septic shock.

    Science.gov (United States)

    Collin, Solène; Sennoun, Nacira; Dron, Anne-Gaëlle; de la Bourdonnaye, Mathilde; Montemont, Chantal; Asfar, Pierre; Lacolley, Patrick; Meziani, Ferhat; Levy, Bruno

    2011-05-01

    To study the activation and expression of vascular (aorta and small mesenteric arteries) potassium channels during septic shock with or without modulation of the NO pathway. Septic shock was induced in rats by peritonitis. Selective inhibitors of vascular K(ATP) (PNU-37883A) or BK(Ca) [iberiotoxin (IbTX)] channels were used to demonstrate their involvement in vascular hyporeactivity. Vascular response to phenylephrine was measured on aorta and small mesenteric arteries mounted on a wire myograph. Vascular expression of potassium channels was studied by PCR and Western blot, in the presence or absence of 1400W, an inducible NO synthase (iNOS) inhibitor. Aortic activation of the transcriptional factor nuclear factor-kappaB (NF-κB) was assessed by electrophoretic mobility shift assay. Arterial pressure as well as in vivo and ex vivo vascular reactivity were reduced by sepsis and improved by PNU-37883A but not by IbTX. Sepsis was associated with an up-regulation of mRNA and protein expression of vascular K(ATP) channels, while expression of vascular BK(Ca) channels remained unchanged. Selective iNOS inhibition blunted the sepsis-induced increase in aortic NO, decreased NF-κB activation, and down-regulated vascular K(ATP) channel expression. Vascular K(ATP) but not BK(Ca) channels are activated, over-expressed, and partially regulated by NO via NF-κB activation during septic shock. Their selective inhibition restores arterial pressure and vascular reactivity and decreases lactate concentration. The present data suggest that selective vascular K(ATP) channel inhibitors offer potential therapeutic perspectives for septic shock.

  13. Calcium channel blockers, more than diuretics, enhance vascular protective effects of angiotensin receptor blockers in salt-loaded hypertensive rats.

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    Eiichiro Yamamoto

    Full Text Available The combination therapy of an angiotensin receptor blocker (ARB with a calcium channel blocker (CCB or with a diuretic is favorably recommended for the treatment of hypertension. However, the difference between these two combination therapies is unclear. The present work was undertaken to examine the possible difference between the two combination therapies in vascular protection. Salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP were divided into 6 groups, and they were orally administered (1 vehicle, (2 olmesartan, an ARB, (3 azelnidipine, a CCB, (4 hydrochlorothiazide, a diuretic, (5 olmesartan combined with azelnidipine, or (6 olmesartan combined with hydrochlorothiazide. Olmesartan combined with either azelnidipine or hydrochlorothiazide ameliorated vascular endothelial dysfunction and remodeling in SHRSP more than did monotherapy with either agent. However, despite a comparable blood pressure lowering effect between the two treatments, azelnidipine enhanced the amelioration of vascular endothelial dysfunction and remodeling by olmesartan to a greater extent than did hydrochlorothiazide in salt-loaded SHRSP. The increased enhancement by azelnidipine of olmesartan-induced vascular protection than by hydrochlorothiazide was associated with a greater amelioration of vascular nicotinamide adenine dinucleotide phosphate (NADPH oxidase activation, superoxide, mitogen-activated protein kinase activation, and with a greater activation of the Akt/endothelial nitric oxide synthase (eNOS pathway. These results provided the first evidence that a CCB potentiates the vascular protective effects of an ARB in salt-sensitive hypertension, compared with a diuretic, and provided a novel rationale explaining the benefit of the combination therapy with an ARB and a CCB.

  14. Canonical Transient Receptor Potential Channels and Their Link with Cardio/Cerebro-Vascular Diseases.

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    Xiao, Xiong; Liu, Hui-Xia; Shen, Kuo; Cao, Wei; Li, Xiao-Qiang

    2017-09-01

    The canonical transient receptor potential channels (TRPCs) constitute a series of nonselective cation channels with variable degrees of Ca 2+ selectivity. TRPCs consist of seven mammalian members, TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7, which are further divided into four subtypes, TRPC1, TRPC2, TRPC4/5, and TRPC3/6/7. These channels take charge of various essential cell functions such as contraction, relaxation, proliferation, and dysfunction. This review, organized into seven main sections, will provide an overview of current knowledge about the underlying pathogenesis of TRPCs in cardio/cerebrovascular diseases, including hypertension, pulmonary arterial hypertension, cardiac hypertrophy, atherosclerosis, arrhythmia, and cerebrovascular ischemia reperfusion injury. Collectively, TRPCs could become a group of drug targets with important physiological functions for the therapy of human cardio/cerebro-vascular diseases.

  15. TRPV1 channels in human skeletal muscle feed arteries: implications for vascular function.

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    Ives, Stephen J; Park, Song Young; Kwon, Oh Sung; Gifford, Jayson R; Andtbacka, Robert H I; Hyngstrom, John R; Richardson, Russell S

    2017-09-01

    What is the central question of this study? We sought to determine whether human skeletal muscle feed arteries (SFMAs) express TRPV 1 channels and what role they play in modulating vascular function. What is the main finding and its importance? Human SMFAs do express functional TRPV 1 channels that modulate vascular function, specifically opposing α-adrenergic receptor-mediated vasocontraction and potentiating vasorelaxation, in an endothelium-dependent manner, as evidenced by the α 1 -receptor-mediated responses. Thus, the vasodilatory role of TRPV 1 channels, and their ligand capsaicin, could be a potential therapeutic target for improving vascular function. Additionally, given the 'sympatholytic' effect of TRPV 1 activation and known endogenous activators (anandamide, reactive oxygen species, H + , etc.), TRPV 1 channels might contribute to functional sympatholysis during exercise. To examine the role of the transient receptor potential vanilloid type 1 (TRPV 1 ) ion channel in the vascular function of human skeletal muscle feed arteries (SMFAs) and whether activation of this heat-sensitive receptor could be involved in modulating vascular function, SMFAs from 16 humans (63 ± 5 years old, range 41-89 years) were studied using wire myography with capsaicin (TRPV 1 agonist) and without (control). Specifically, phenylephrine (α 1 -adrenergic receptor agonist), dexmedetomidine (α 2 -adrenergic receptor agonist), ACh and sodium nitroprusside concentration-response curves were established to assess the role of TRPV 1 channels in α-receptor-mediated vasocontraction as well as endothelium-dependent and -independent vasorelaxation, respectively. Compared with control conditions, capsaicin significantly attenuated maximal vasocontraction in response to phenylephrine [control, 52 ± 8% length-tension max (LT max ) and capsaicin, 21 ± 5%LT max ] and dexmedetomidine (control, 29 ± 12%LT max and capsaicin, 2 ± 3%LT max ), while robustly enhancing maximal

  16. Decreased expression of transient receptor potential channels in cerebral vascular tissue from patients after hypertensive intracerebral hemorrhage

    DEFF Research Database (Denmark)

    Thilo, Florian; Suess, Olaf; Liu, Ying

    2011-01-01

    , TRPC5, TRPC6, TRPM4, TRPM6, and TRPM7 channels were detected in cerebral vascular tissue by quantitative real-time RT-PCR. Control cerebral vascular tissue was obtained from normotensive patients who underwent neurosurgical operation because of brain tumor. To examine a possible relation between...

  17. The role of L-type calcium channels in the vascular effect of Trigonella foenum-graecum L. in diabetic rats

    Directory of Open Access Journals (Sweden)

    Mehrdad Roghani

    2006-03-01

    Full Text Available Some ion channels like voltage-operated calcium channels (VOCC within the plasma membrane of vascular muscle cells from the walls of resistance arteries and arterioles play a central role in the regulation of vascular tone. On the basis of reports about the beneficial attenuating effect of fenugreek (Trigonella foenum-graecum L.; TFG on the contractile reactivity of aortic rings of diabetic rats, this study was carried out to evaluate the possible involvement of L-type voltage-operated calcium channels in the vascular effect of this medicinal plant. For this purpose, male Wistar rats were made diabetic using streptozotocin (STZ, 60 mg/Kg, i.p. The extract-treated control and diabetic rats received aqueous leaf extract of TFG (200 mg/Kg, i.p. every other day for two months. At the end of the study, contractile response of isolated aortic rings to KCl and noreadrenaline (NA was determined in the absence and presence of the calcium channel blocker nifedipine. The results showed that aortic rings from diabetic rats are more responsive to the effect of KCl and NA than those of controls, TFG extract treatment could attenuate the enhanced contractile response of aortic rings of diabetic rats, and nifedipine pretreatment could partially neutralize the beneficial effect of this extract. It is concluded that TFG extract attenuates the enhanced vascular reactivity in chronic diabetic rats and voltage-operated calcium channels are in part responsible for this effect of TFG extract.

  18. The genetic background affects the vascular response in T-type calcium channels 3.2 deficient mice

    DEFF Research Database (Denmark)

    Svenningsen, Per; Hansen, Pernille B L

    2016-01-01

    -type channels are the dominant Ca(2+) entry pathway in vascular smooth muscle cells, however, T-type calcium channels are also expressed in the cardiovascular system where they play a functional role in the regulation of both contraction and vasodilation in (Chen et al. 2003; Hansen et al. 2001). This article...... is protected by copyright. All rights reserved....

  19. Interventional C-arm tomosynthesis for vascular imaging: initial results

    Science.gov (United States)

    Langan, David A.; Claus, Bernhard E. H.; Al Assad, Omar; Trousset, Yves; Riddell, Cyril; Avignon, Gregoire; Solomon, Stephen B.; Lai, Hao; Wang, Xin

    2015-03-01

    As percutaneous endovascular procedures address more complex and broader disease states, there is an increasing need for intra-procedure 3D vascular imaging. In this paper, we investigate C-Arm 2-axis tomosynthesis ("Tomo") as an alternative to C-Arm Cone Beam Computed Tomography (CBCT) for workflow situations in which the CBCT acquisition may be inconvenient or prohibited. We report on our experience in performing tomosynthesis acquisitions with a digital angiographic imaging system (GE Healthcare Innova 4100 Angiographic Imaging System, Milwaukee, WI). During a tomo acquisition the detector and tube each orbit on a plane above and below the table respectively. The tomo orbit may be circular or elliptical, and the tomographic half-angle in our studies varied from approximately 16 to 28 degrees as a function of orbit period. The trajectory, geometric calibration, and gantry performance are presented. We overview a multi-resolution iterative reconstruction employing compressed sensing techniques to mitigate artifacts associated with incomplete data reconstructions. In this work, we focus on the reconstruction of small high contrast objects such as iodinated vasculature and interventional devices. We evaluate the overall performance of the acquisition and reconstruction through phantom acquisitions and a swine study. Both tomo and comparable CBCT acquisitions were performed during the swine study thereby enabling the use of CBCT as a reference in the evaluation of tomo vascular imaging. We close with a discussion of potential clinical applications for tomo, reflecting on the imaging and workflow results achieved.

  20. Update on vascular endothelial Ca(2+) signalling: A tale of ion channels, pumps and transporters.

    Science.gov (United States)

    Moccia, Francesco; Berra-Romani, Roberto; Tanzi, Franco

    2012-07-26

    A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca(2+) signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca(2+) levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca(2+) signals, ranging from brief, localized Ca(2+) pulses to prolonged Ca(2+) oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca(2+) signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca(2+) releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca(2+) removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca(2+) machinery in vascular ECs under both physiological and pathological conditions.

  1. Update on vascular endothelial Ca2+ signalling: A tale of ion channels, pumps and transporters

    Science.gov (United States)

    Moccia, Francesco; Berra-Romani, Roberto; Tanzi, Franco

    2012-01-01

    A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions. PMID:22905291

  2. Tungstate-targeting of BKαβ1 channels tunes ERK phosphorylation and cell proliferation in human vascular smooth muscle.

    Directory of Open Access Journals (Sweden)

    Ana Isabel Fernández-Mariño

    Full Text Available Despite the substantial knowledge on the antidiabetic, antiobesity and antihypertensive actions of tungstate, information on its primary target/s is scarce. Tungstate activates both the ERK1/2 pathway and the vascular voltage- and Ca2+-dependent large-conductance BKαβ1 potassium channel, which modulates vascular smooth muscle cell (VSMC proliferation and function, respectively. Here, we have assessed the possible involvement of BKαβ1 channels in the tungstate-induced ERK phosphorylation and its relevance for VSMC proliferation. Western blot analysis in HEK cell lines showed that expression of vascular BKαβ1 channels potentiates the tungstate-induced ERK1/2 phosphorylation in a Gi/o protein-dependent manner. Tungstate activated BKαβ1 channels upstream of G proteins as channel activation was not altered by the inhibition of G proteins with GDPβS or pertussis toxin. Moreover, analysis of Gi/o protein activation measuring the FRET among heterologously expressed Gi protein subunits suggested that tungstate-targeting of BKαβ1 channels promotes G protein activation. Single channel recordings on VSMCs from wild-type and β1-knockout mice indicated that the presence of the regulatory β1 subunit was essential for the tungstate-mediated activation of BK channels in VSMCs. Moreover, the specific BK channel blocker iberiotoxin lowered tungstate-induced ERK phosphorylation by 55% and partially reverted (by 51% the tungstate-produced reduction of platelet-derived growth factor (PDGF-induced proliferation in human VSMCs. Our observations indicate that tungstate-targeting of BKαβ1 channels promotes activation of PTX-sensitive Gi proteins to enhance the tungstate-induced phosphorylation of ERK, and inhibits PDGF-stimulated cell proliferation in human vascular smooth muscle.

  3. Tungstate-Targeting of BKαβ1 Channels Tunes ERK Phosphorylation and Cell Proliferation in Human Vascular Smooth Muscle

    OpenAIRE

    López López, José Ramón; Fernández Mariño, Ana Isabel; Cidad, Pilar; Zafra, Delia; Nocito, Laura; Domínguez, Jorge; Oliván Viguera, Aida; Köhler, Ralf; Pérez García, María Teresa; Valverde, Miguel Ángel; Guinovart, Joan J.; Fernández Fernández, José Manuel

    2015-01-01

    Producción Científica Despite the substantial knowledge on the antidiabetic, antiobesity and antihypertensive actions of tungstate, information on its primary target/s is scarce. Tungstate activates both the ERK1/2 pathway and the vascular voltage- and Ca2+-dependent large-conductance BKαβ1 potassium channel, which modulates vascular smooth muscle cell (VSMC) proliferation and function, respectively. Here, we have assessed the possible involvement of BKαβ1 channels in the tungstate-induced...

  4. Experimental results and clinical impact of using autologous rectus fascia sheath for vascular replacement

    NARCIS (Netherlands)

    Kobori, Laszlo; Nemeth, Tibor; Nagy, Peter; Dallos, Gabor; Sotonyi, Peter; Fehervari, Imre; Nemes, Balazs; Gorog, Denes; Patonai, Attila; Monostory, Katalin; Doros, Attila; Sarvary, Enikoe; Fazakas, Janos; Gerlei, Zsuzsanna; Benkoe, Tamas; Piros, Laszlo; Jaray, Jeno; De Jong, Koert P.

    Vascular complications are major causes of graft failure in liver transplantation. The use of different vascular grafts is common but the results are controversial. The aim of this study was to create an 'ideal' arterial interponate for vascular replacements in the clinical field. An autologous,

  5. Results of the examination of channel H12/1

    International Nuclear Information System (INIS)

    Bauer, E.

    1983-01-01

    Channel H12/1 is one part of the channel unit of the High-Flux Reactor that has been affected by corrosion attack. It was disassembled after the appearance of a heavy water leak and examined in a hot cell. Results of the examination are presented

  6. Hypothenar hammer syndrome: long-term results of vascular reconstruction.

    Science.gov (United States)

    Endress, Ryan D; Johnson, Craig H; Bishop, Allen T; Shin, Alexander Y

    2015-04-01

    To evaluate long-term patency rates and related outcomes after vascular reconstruction of hypothenar hammer syndrome and identify patient- or treatment-related factors that may contribute to differences in outcome. We used color flow ultrasound to determine the patency of 18 vein graft reconstructions of the ulnar artery at the wrist in 16 patients. Validated questionnaires evaluated patients' functional disability with the Disabilities of the Arm, Shoulder, and Hand score, pain with the visual analog scale, and cold intolerance with the Cold Intolerance Symptom Severity survey. Patient demographics, clinical data, and surgical factors were analyzed for association with graft failure. Patients were asked to grade the result of treatment on a scale of 0 to 10. Of 18 grafts, 14 (78%) were occluded at a mean of 118 months postoperatively. Patients with patent grafts had significantly less disability related to cold intolerance according to the Cold Intolerance Symptom Severity survey in addition to significantly less pain on the visual analog scale. There was no statistical difference in Disabilities of the Arm, Shoulder, and Hand scores between patients with patent or occluded grafts. Patients graded the result significantly higher in patent reconstructions. We noted a higher incidence of graft occlusion than previously reported at a mean follow-up of 9.8 years, which represents a long-duration follow-up study of surgical treatment of hypothenar hammer syndrome. Despite a high percentage of occlusion, overall, patients remained satisfied with low functional disability and all would recommend surgical reconstruction. This study suggests that improved outcomes may result from patent grafts in the long term. Prognostic IV. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  7. Results from the Australasian Vascular Surgical Audit: the inaugural year.

    Science.gov (United States)

    Beiles, C Barry; Bourke, Bernie; Thomson, Ian

    2012-03-01

    The Australian and New Zealand Society for Vascular Surgery has incorporated a constitutional change to administer a self-funded compulsory vascular surgery audit since January 2010. This is a bi-national quality assurance activity that captures all procedures performed in both countries. Data is collected at two points in the clinical admission; at operation and at discharge and data entry is via the Internet. Security is stringent and confidentiality is guaranteed by Commonwealth privilege. Data privacy is maximized by encryption. The application is flexible and administered by a dedicated administrator with a help-desk facility. Reports are available to provide real-time feedback of user performance compared with the peer group data in key categories of arterial surgery. A structured hierarchy for data management has been established to assess four main categories of performance: mortality after aortic surgery, stroke and death after carotid surgery, patency and limb salvage after infrainguinal bypass and patency after arteriovenous access for haemodialysis. Data is analysed using risk-adjustment techniques and an algorithm for management of underperformance has been followed. Data validation has been performed. The outcomes in all categories have been of a high standard and correction of erroneous data in a single statistical outlier has negated underperformance. The audit has captured only 65% of the estimated procedures in Australia in the first year, but data quality is good. The feasibility of a complete compulsory bi-national audit has now been established and will be the benchmark for other craft groups in the current environment of accountability. © 2012 The Authors. ANZ Journal of Surgery © 2012 Royal Australasian College of Surgeons.

  8. Flow patterns from metallic vascular endoprostheses: in vitro results

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Huelsbeck, S.; Grimm, J.; Jahnke, T.; Haeselbarth, G.; Heller, M. [Dept. of Radiology, University Hospital, Kiel (Germany)

    2001-05-01

    The aim of this study was to determine flow characteristics and pressure gradients of different balloon- and self-expandable stents in an in vitro flow-model. Seven vascular stents (Bridge, Cragg, Memotherm, Palmaz PS 784, Sinus, Symphony, Wallstent), equal in length (60 mm) and diameter (10 mm), were deployed in a closed flow model. The inner diameter of the tube measured 9 mm. Flow at 1.5 and 6 l/min was applied. Flow patterns were visualized by anionic particles illuminated with two helium-neon lasers. Late laminary flow characteristics and pre- /post-stent pressure gradients were determined in either expanded stent, 25 and 50 % tube stenosis. Stent implantation induced a decrease of laminary flow when compared with an unstented tube with and without concentric 25 % stenosis (p < 0.01) at all flow rates and an increase of pressure gradients when compared with an unstented tube for a flow rate of 6 l/min and all stenoses (p < 0.01). At 1.5 l/min most stents revealed no significant change of pressure gradient, the highest gradient measured 4.0 mmHg. Sinus permitted maximum (expanded: 82.1 % and 76.9 % at 25 % stenosis at 1.5 l/min; p < 0.01) and Palmaz minimum of laminary flow at all flow rates and stenoses (70.2 and 52.4 % at 25 % stenosis at 1.5 l/min; p < 0.01). At 6 l/min, when completely expanded, Sinus is equal to Bridge and Memotherm; in 25 % stenosis Sinus is equal to Bridge, Memotherm, and additionally to Cragg and Wall. None of the endoprostheses revealed laminary flow at 50 % stenosis. Inadequate stent deployment bears the risk of creating less laminary flow and pressure gradients. Since flow disturbances and pressure gradients may influence neointimal hyperplasia, stent design and completeness of stent expansion are important factors regarding the appearance of thrombus formation and postinterventional restenosis. (orig.)

  9. Aberrant Splicing Induced by Dysregulated Rbfox2 Produces Enhanced Function of CaV1.2 Calcium Channel and Vascular Myogenic Tone in Hypertension.

    Science.gov (United States)

    Zhou, Yingying; Fan, Jia; Zhu, Huayuan; Ji, Li; Fan, Wenyong; Kapoor, Isha; Wang, Yue; Wang, Yuan; Zhu, Guoqing; Wang, Juejin

    2017-12-01

    Calcium influx from activated voltage-gated calcium channel Ca V 1.2 in vascular smooth muscle cells is indispensable for maintaining myogenic tone and blood pressure. The function of Ca V 1.2 channel can be optimized by alternative splicing, one of post-transcriptional modification mechanisms. The splicing factor Rbfox2 is known to regulate the Ca V 1.2 pre-mRNA alternative splicing events during neuronal development. However, Rbfox2's roles in modulating the key function of vascular Ca V 1.2 channel and in the pathogenesis of hypertension remain elusive. Here, we report that the proportion of Ca V 1.2 channels with alternative exon 9* is increased by 10.3%, whereas that with alternative exon 33 is decreased by 10.5% in hypertensive arteries. Surprisingly, the expression level of Rbfox2 is increased ≈3-folds, presumably because of the upregulation of a dominant-negative isoform of Rbfox2. In vascular smooth muscle cells, we find that knockdown of Rbfox2 dynamically increases alternative exon 9*, whereas decreases exon 33 inclusion of Ca V 1.2 channels. By patch-clamp studies, we show that diminished Rbfox2-induced alternative splicing shifts the steady-state activation and inactivation curves of vascular Ca V 1.2 calcium channel to hyperpolarization, which makes the window current potential to more negative. Moreover, siRNA-mediated knockdown of Rbfox2 increases the pressure-induced vascular myogenic tone of rat mesenteric artery. Taken together, our data indicate that Rbfox2 modulates the functions of vascular Ca V 1.2 calcium channel by dynamically regulating the expressions of alternative exons 9* and 33, which in turn affects the vascular myogenic tone. Therefore, our work suggests a key role for Rbfox2 in hypertension, which provides a rational basis for designing antihypertensive therapies. © 2017 American Heart Association, Inc.

  10. Vascular access for hemodialysis. Patency rates and results of revision.

    Science.gov (United States)

    Palder, S B; Kirkman, R L; Whittemore, A D; Hakim, R M; Lazarus, J M; Tilney, N L

    1985-08-01

    Over a 4-year interval, 324 arteriovenous conduits were created in 256 patients with end-stage renal disease as access for chronic hemodialysis. These included 154 Cimino fistulae, 163 polytetrafluoroethylene (PTFE) grafts, and seven miscellaneous grafts. Satisfactory patency rates were demonstrated for as long as 4 years for both Cimino fistulae and PTFE grafts by life-table analysis. Failures of Cimino fistulae usually occurred early in the postoperative period, secondary to attempts to use inadequate veins. Thrombosis caused the majority of PTFE graft failures and was generally the result of venous stenosis. Correction of such venous stenosis is mandatory to restore graft patency and can result in prolonged graft survival.

  11. Differential expression of BK channel isoforms and beta-subunits in rat neuro-vascular tissues

    DEFF Research Database (Denmark)

    Poulsen, Asser Nyander; Wulf, Helle; Hay-Schmidt, Anders

    2009-01-01

    We investigated the expression of splice variants and beta-subunits of the BK channel (big conductance Ca(2+)-activated K(+) channel, Slo1, MaxiK, K(Ca)1.1) in rat cerebral blood vessels, meninges, trigeminal ganglion among other tissues. An alpha-subunit splice variant X1(+24) was found expresse...

  12. Results From a Channel Restoration Project: Hydraulic Design Considerations

    Science.gov (United States)

    Karle, K.F.; Densmore, R.V.; ,

    2001-01-01

    Techniques for the hydraulic restoration of placer-mined streams and floodplains were developed in Denali National Park and Preserve, Alaska. The two-year study at Glen Creek focused on a design of stream and floodplain geometry using hydraulic capacity and shear stress equations. Slope and sinuosity values were based on regional relationships. Design requirements included a channel capacity for a bankfull discharge and a floodplain capacity for a 1.5- to 100-year discharge. Several bio-engineering techniques using alder and willow, including anchored brush bars, streambank hedge layering, seedlings, and cuttings, were tested to dissipate floodwater energy and encourage sediment deposition until natural revegetation stabilized the new floodplains. Permanently monumented cross-sections installed throughout the project site were surveyed every one to three years. Nine years after the project began, a summer flood caused substantial damage to the channel form, including a change in width/depth ratio, slope, and thalweg location. Many of the alder brush bars were heavily damaged or destroyed, resulting in significant bank erosion. This paper reviews the original hydraulic design process, and describes changes to the channel and floodplain geometry over time, based on nine years of cross-section surveys.

  13. Dual channel photoplethysmography studies of cardio-vascular response to the body position changes

    Science.gov (United States)

    Erts, R.; Kukulis, I.; Spigulis, J.; Kere, L.

    2005-08-01

    The dual-channel photoplethysmography studies of physiological responses during 3-stage orthostatic test were performed. Clear differences in heartbeat rate, pulse wave transit time and blood pressure variations of healthy volunteers and diabetic patients have been observed.

  14. Statin therapy exacerbates alcohol-induced constriction of cerebral arteries via modulation of ethanol-induced BK channel inhibition in vascular smooth muscle.

    Science.gov (United States)

    Simakova, Maria N; Bisen, Shivantika; Dopico, Alex M; Bukiya, Anna N

    2017-12-01

    Statins constitute the most commonly prescribed drugs to decrease cholesterol (CLR). CLR is an important modulator of alcohol-induced cerebral artery constriction (AICAC). Using rats on a high CLR diet (2% CLR) we set to determine whether atorvastatin administration (10mg/kg daily for 18-23weeks) modified AICAC. Middle cerebral arteries were pressurized in vitro at 60mmHg and AICAC was evoked by 50mM ethanol, that is within the range of blood alcohol detected in humans following moderate-to-heavy drinking. AICAC was evident in high CLR+atorvastatin group but not in high CLR diet+placebo. Statin exacerbation of AICAC persisted in de-endothelialized arteries, and was blunted by CLR enrichment in vitro. Fluorescence imaging of filipin-stained arteries showed that atorvastatin decreased vascular smooth muscle (VSM) CLR when compared to placebo, this difference being reduced by CLR enrichment in vitro. Voltage- and calcium-gated potassium channels of large conductance (BK) are known VSM targets of ethanol, with their beta1 subunit being necessary for ethanol-induced channel inhibition and resulting AICAC. Ethanol-induced BK inhibition in excised membrane patches from freshly isolated myocytes was exacerbated in the high CLR diet+atorvastatin group when compared to high CLR diet+placebo. Unexpectedly, atorvastatin decreased the amount and function of BK beta1 subunit as documented by immunofluorescence imaging and functional patch-clamp studies. Atorvastatin exacerbation of ethanol-induced BK inhibition disappeared upon artery CLR enrichment in vitro. Our study demonstrates for the first time statin's ability to exacerbate the vascular effect of a widely consumed drug of abuse, this exacerbation being driven by statin modulation of ethanol-induced BK channel inhibition in the VSM via CLR-mediated mechanism. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. ACTIVITIES RESULTS AIMED AT IMPROVED MEDICAL ASSISTANCE TO THE VASCULAR PATIENTS IN TOMSK REGION

    Directory of Open Access Journals (Sweden)

    D. M. Plotnikov

    2013-01-01

    Full Text Available Acute disorders of cerebral circulation remain serious medical and social problem associated with high disability and mortality rates. Since 2011 Tomsk oblast is a participating member of the medical campaign aimed at improved medical services to the vascular patients. The preliminary implementation data analysis for 2012 revealed improvement of most of the indices of medical support to patients suffering from acute cerebral circulation; increased number of the in-patient cases (Regional Vascular Center and primary vascular department, decreased lethality rates from strokes, specifically hemorrhagic cases. Strict observance of the Regulations on Medical Assistance for stroke patients and the using of modern methods of therapy allowed to decrease hospital mortality in the Primary Vascular Departments and early mortality in the Regional Vascular Center. The active implementation of neurorehabilitation approaches resulted in the increased number of patients who do not require third parties’ assistance. Analysis of the work of the departments helped to identifying current problems and perspectives of further development of special medical care for stroke patients.

  16. Correct diagnosis of vascular encasement and longitudinal extension of hilar cholangiocarcinoma by four-channel multidetector-row computed tomography

    International Nuclear Information System (INIS)

    Okumoto, Tadayuki; Yamada, Takayuki; Sato, Akihiro

    2009-01-01

    Accurate diagnosis of local invasion of hilar cholangiocarcinomas is challenging due to their small size and the anatomic complexity of the hepatic hilar region. On the other hand, the correct diagnosis of local invasion is essential for assuring the possibility of curative surgery. The purpose of this study was to evaluate the feasibility of four-channel multidetector-row computed tomography (MDCT) in the assessment of vascular and bile duct involvement, by which we could obtain useful information for the surgical management of hilar cholangiocarcinoma. The subjects were 18 patients for whom the extent of tumor invasion was surgically and pathologically confirmed. All patients underwent preoperative multiphasic CT scanning by MDCT. Arterial and portal dominant phases were acquired using a detector configuration of 1.25 mm x 4 mm, and both axial and multiplanar reconstructed images were interpreted. Longitudinal extension was evaluated up to second-order branches. Vascular invasion is considered to be the degree of tumor contiguity to the hepatic arteries and portal vein and was graded by CT. The longitudinal extension was correctly diagnosed in 14 patients (77.8%). Hepatic artery invasion was correctly diagnosed in 17 patients with sensitivity of 100% and specificity of 90%, respectively. Portal vein invasion was correctly diagnosed in 47 of 51 branches with sensitivity and specificity of 92.3% and 90.2%, respectively. Multiplanar reconstructed images contributed to the correct diagnosis for both vascular encasement and longitudinal tumor extension. In conclusion, MDCT is useful in preoperative evaluation of hilar cholangiocarcinoma, especially when combined with multiplanar reconstructed images. (author)

  17. COMMISSIONING AND FIRST RESULTS FROM CHANNELING RADIATION AT FAST

    Energy Technology Data Exchange (ETDEWEB)

    Halavanau, A. [NIU, DeKalb; Mihalcea, D. [NIU, DeKalb; Broemmelsiek, D. [Fermilab; Edstrom, D. [Fermilab; Sen, T. [Fermilab; Romanov, A. [Fermilab; Ruan, J. [Fermilab; Shiltsev, V. [Fermilab; Kobak, P. [BYU-I; Rush, W. [Kansas U.; Hyun, J. [Tsukuba, Graduate U. Adv. Studies

    2016-10-18

    X-rays have widespread applications in science and industry, but developing a simple, compact, and high-quality X-ray source remains a challenge. Our collaboration has explored the possible use of channeling radiation driven by a 50 MeV low-emittance electron beam to produce narrowband hard X-rays with photon energy of 40 to 140 keV [8,9,11]. Here we present the simulated X-ray spectra including the background bremsstrahlung contribution, and a description of the required optimization of the relevant electron-beam parameters necessary to maximize brilliance of the resulting X-ray beam. Results are presented from our test of this, carried out at the Fermilab Accelerator Science & Technology (FAST) facility’s 50-MeV low-energy electron injector. As a result of the beam parameters, made possible by the photo-injector based SRF linac, the average brilliance at FAST was expected to be about one order of magnitude higher than that in previous experiments.

  18. Soluble adenylyl cyclase in vascular endothelium: gene expression control of epithelial sodium channel-α, Na+/K+-ATPase-α/β, and mineralocorticoid receptor.

    Science.gov (United States)

    Schmitz, Boris; Nedele, Johanna; Guske, Katrin; Maase, Martina; Lenders, Malte; Schelleckes, Michael; Kusche-Vihrog, Kristina; Brand, Stefan-Martin; Brand, Eva

    2014-04-01

    The Ca(2+)- and bicarbonate-activated soluble adenylyl cyclase (sAC) has been identified recently as an important mediator of aldosterone signaling in the kidney. Nuclear sAC has been reported to stimulate cAMP response element-binding protein 1 phosphorylation via protein kinase A, suggesting an alternative cAMP pathway in the nucleus. In this study, we analyzed the sAC as a potential modulator of endothelial stiffness in the vascular endothelium. We determined the contribution of sAC to cAMP response element-mediated transcriptional activation in vascular endothelial cells and kidney collecting duct cells. Inhibition of sAC by the specific inhibitor KH7 significantly reduced cAMP response element-mediated promoter activity and affected cAMP response element-binding protein 1 phosphorylation. Furthermore, KH7 and anti-sAC small interfering RNA significantly decreased mRNA and protein levels of epithelial sodium channel-α and Na(+)/K(+)-ATPase-α. Using atomic force microscopy, a nano-technique that measures stiffness and deformability of living cells, we detected significant endothelial cell softening after sAC inhibition. Our results suggest that the sAC is a regulator of gene expression involved in aldosterone signaling and an important regulator of endothelial stiffness. Additional studies are warranted to investigate the protective action of sAC inhibitors in humans for potential clinical use.

  19. Chronic deficit in nitric oxide elicits oxidative stress and augments T-type calcium-channel contribution to vascular tone of rodent arteries and arterioles

    DEFF Research Database (Denmark)

    Howitt, Lauren; Kuo, Ivana Y; Ellis, Anthie

    2013-01-01

    arteries in vitro and skeletal muscle arterioles in vivo to study the contribution of L-type (1 µmol/L nifedipine) and T-type (1 µmol/L mibefradil, 3 µmol/L NNC 55-0396) calcium channels to vascular tone, following acute or chronic inhibition of nitric oxide. Acute inhibition with l-NAME (10 µmol...... was reversed by acute scavenging of superoxide with tempol (1 mmol/L), or inhibition of NADPH oxidase with apocynin (500 µmol/L) or DPI (5 µmol/L). CONCLUSION: We conclude that nitric oxide deficit produces a significant increase in the contribution of Cav3.1 and Cav3.2 T-type calcium channels to vascular tone......, by regulating the bioavailability of reactive oxygen species produced by NADPH oxidase. Our data provide evidence for a novel causal link between nitric oxide deficit, oxidative stress, and T-type calcium channel function....

  20. Episodic vertigo resulting from vascular risk factors, cervical spondylosis and head rotation: Two case reports.

    Science.gov (United States)

    Owolabi, Mayowa O; Ogah, Okechukwu S; Ogunniyi, Adesola

    2007-01-01

    Vascular risk factors predispose to vertebrobasilar ischemia. Cervical osteophytes can impinge on the vertebral artery causing mechanical occlusion during head turning. Presentation with vertigo in such instances is a common finding. A patient with obesity, hyperlipidemia, hypertension, cervical spondylosis, and vertigo triggered by head rotation is presented. She responded to antihypertensive and lipid-lowering drugs, vestibular sedative and application of cervical collar. The second patient also exhibited similar features and responded to conservative treatment. Rotational vertebral artery occlusion resulting from cervical spondylosis in the presence of atherosclerosed collateral vessels is a cause of posterior circulation insufficiency manifesting as vertigo. The tetrad of vertigo resulting from vascular risk factors, cervical spondylosis, and head rotation is proposed for further research.

  1. Clinical results of stereotactic heavy-charged-particle radiosurgery for intracranial angiographically occult vascular malformations

    International Nuclear Information System (INIS)

    Levy, R.P.; Fabrikant, J.I.; Phillips, M.H.; Frankel, K.A.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.; Lyman, J.T.

    1989-12-01

    Angiographically occult vascular malformations (AOVMs) of the brain have been recognized for many years to cause neurologic morbidity and mortality. They generally become symptomatic due to intracranial hemorrhage, focal mass effect, seizures or headaches. The true incidence of AOVMs is unknown, but autopsy studies suggest that they are more common than high-flow angiographically demonstrable arteriovenous malformations (AVMs). We have developed stereotactic heavy-charged-particle Bragg peak radiosurgery for the treatment of inoperable intracranial vascular malformations, using the helium ion beams at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron and Bevatron. This report describes the protocol for patient selection, radiosurgical treatment planning method, clinical and neuroradiologic results and complications encountered, and discusses the strengths and limitations of the method. 10 refs., 1 fig

  2. Clinical results of stereotactic heavy-charged-particle radiosurgery for intracranial angiographically occult vascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.; Fabrikant, J.I.; Phillips, M.H.; Frankel, K.A.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.; Lyman, J.T.

    1989-12-01

    Angiographically occult vascular malformations (AOVMs) of the brain have been recognized for many years to cause neurologic morbidity and mortality. They generally become symptomatic due to intracranial hemorrhage, focal mass effect, seizures or headaches. The true incidence of AOVMs is unknown, but autopsy studies suggest that they are more common than high-flow angiographically demonstrable arteriovenous malformations (AVMs). We have developed stereotactic heavy-charged-particle Bragg peak radiosurgery for the treatment of inoperable intracranial vascular malformations, using the helium ion beams at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron and Bevatron. This report describes the protocol for patient selection, radiosurgical treatment planning method, clinical and neuroradiologic results and complications encountered, and discusses the strengths and limitations of the method. 10 refs., 1 fig.

  3. Whole-body MRI: comprehensive evaluation on a 48-channel 3T MRI system in less than 40 minutes. Preliminary results

    Directory of Open Access Journals (Sweden)

    Mateus de Andrade Hernandes

    2012-12-01

    Full Text Available OBJECTIVE: To evaluate a comprehensive MRI protocol that investigates for cancer, vascular disease, and degenerative/inflammatory disease from the head to the pelvis in less than 40 minutes on a new generation 48-channel 3T system. MATERIALS AND METHODS: All MR studies were performed on a 48-channel 3T MR scanner. A 20-channel head/neck coil, two 18-channel body arrays, and a 32-channel spine array were employed. A total of 4 healthy individuals were studied. The designed protocol included a combination of single-shot T2-weighted sequences, T1-weighted 3D gradient-echo pre- and post-gadolinium. All images were retrospectively evaluated by two radiologists independently for overall image quality. RESULTS: The image quality for cancer was rated as excellent in the liver, pancreas, kidneys, lungs, pelvic organs, and brain, and rated as fair in the colon and breast. For vascular diseases ratings were excellent in the aorta, major branch vessel origins, inferior vena cava, portal and hepatic veins, rated as good in pulmonary arteries, and as poor in the coronary arteries. For degenerative/inflammatory diseases ratings were excellent in the brain, liver and pancreas. The inter-observer agreement was excellent. CONCLUSION: A comprehensive and time efficient screening for important categories of disease processes may be achieved with high quality imaging in a new generation 48-channel 3T system.

  4. Whole-body MRI: comprehensive evaluation on a 48-channel 3T MRI system in less than 40 minutes. Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Hernandes, Mateus de Andrade; Semelka, Richard C.; Bamrungchart, Saraporn; Stallings, Clifton, E-mail: richsem@med.unc.edu [Department of Radiology, University of North Carolina, Chapel Hill, NC (United States); Elias Junior, Jorge [Imaging and Medical Physics Center, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP (Brazil); Dale, Brian M. [Siemens Medical Solutions USA, Inc., Cary, NC (United States)

    2012-11-15

    Objective: To evaluate a comprehensive MRI protocol that investigates for cancer, vascular disease, and degenerative/inflammatory disease from the head to the pelvis in less than 40 minutes on a new generation 48-channel 3T system. Materials and Methods: All MR studies were performed on a 48-channel 3T MR scanner. A 20-channel head/neck coil, two 18-channel body arrays, and a 32-channel spine array were employed. A total of 4 healthy individuals were studied. The designed protocol included a combination of single-shot T2-weighted sequences, T1-weighted 3D gradient echo pre- and post-gadolinium. All images were retrospectively evaluated by two radiologists independently for overall image quality. Results: The image quality for cancer was rated as excellent in the liver, pancreas, kidneys, lungs, pelvic organs, and brain, and rated as fair in the colon and breast. For vascular diseases ratings were excellent in the aorta, major branch vessel origins, inferior vena cava, portal and hepatic veins, rated as good in pulmonary arteries, and as poor in the coronary arteries. For degenerative/inflammatory diseases ratings were excellent in the brain, liver and pancreas. The inter-observer agreement was excellent. Conclusion: A comprehensive and time efficient screening for important categories of disease processes may be achieved with high quality imaging in a new generation 48-channel 3T system. (author)

  5. The Utility of 64 Channel Multidetector CT Angiography for Evaluating the Renal Vascular Anatomy and Possible Variations: a Pictorial Essay

    International Nuclear Information System (INIS)

    Kumar, Sheo; Neyaz, Zafar; Gupta, Archna

    2010-01-01

    The increased use of laparoscopic nephrectomy and nephron-sparing surgery has prompted the need for a more detailed radiological evaluation of the renal vascular anatomy. Multidetector CT angiography is a fast and accurate modality for assessing the precise anatomy of the renal vessels. In this pictorial review, we present the multidetector CT angiography appearances of the normal renal vascular anatomy and a spectrum of various anomalies that require accurate vascular depiction before undergoing surgical treatment

  6. The Utility of 64 Channel Multidetector CT Angiography for Evaluating the Renal Vascular Anatomy and Possible Variations: a Pictorial Essay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sheo; Neyaz, Zafar; Gupta, Archna [Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India)

    2010-06-15

    The increased use of laparoscopic nephrectomy and nephron-sparing surgery has prompted the need for a more detailed radiological evaluation of the renal vascular anatomy. Multidetector CT angiography is a fast and accurate modality for assessing the precise anatomy of the renal vessels. In this pictorial review, we present the multidetector CT angiography appearances of the normal renal vascular anatomy and a spectrum of various anomalies that require accurate vascular depiction before undergoing surgical treatment.

  7. The utility of 64 channel multidetector CT angiography for evaluating the renal vascular anatomy and possible variations: a pictorial essay.

    Science.gov (United States)

    Kumar, Sheo; Neyaz, Zafar; Gupta, Archna

    2010-01-01

    The increased use of laparoscopic nephrectomy and nephron-sparing surgery has prompted the need for a more detailed radiological evaluation of the renal vascular anatomy. Multidetector CT angiography is a fast and accurate modality for assessing the precise anatomy of the renal vessels. In this pictorial review, we present the multidetector CT angiography appearances of the normal renal vascular anatomy and a spectrum of various anomalies that require accurate vascular depiction before undergoing surgical treatment.

  8. Modulation of CaV1.2 calcium channel by neuropeptide W regulates vascular myogenic tone via G protein-coupled receptor 7.

    Science.gov (United States)

    Ji, Li; Zhu, Huayuan; Chen, Hong; Fan, Wenyong; Chen, Junjie; Chen, Jing; Zhu, Guoqing; Wang, Juejin

    2015-12-01

    Neuropeptide W (NPW), an endogenous ligand for the G protein-coupled receptor 7 (GPR7), was first found to make important roles in central nerve system. In periphery, NPW was also present and regulated intracellular calcium homeostasis by L-type calcium channels. This study was designed to discover the effects of NPW-GPR7 on the function of CaV1.2 calcium channels in the vascular smooth muscle cells (VSMCs) and vasotone of arterial vessels. By whole-cell patch clamp, we studied the effects of NPW-23, the active form of NPW, on the CaV1.2 channels in the heterologously transfected human embryonic kidney 293 cells and VSMCs isolated from rat. Living system was used to explore the physiological function of NPW-23 in arterial myogenic tone. To investigate the pathological relevance, NPW mRNA level of mesenteric arteries was measured in the hypertensive and normotensive rats. NPW's receptor GPR7 was coexpressed with CaV1.2 channels in arterial smooth muscle. NPW-23 increased the ICa,L in transfected human embryonic kidney 293 cells and VSMCs via GPR7, which could be abrogated by phospholipase C (PLC)/protein kinase C (PKC) inhibitors, not protein kinase A or protein kinase G inhibitor. After NPW-23 application, the expression of pan phospho-PKC was increased; moreover, intracellular diacylglycerol level, the second messenger catalyzed by PLC, was increased 1.5-2-fold. Application with NPW-23 increased pressure-induced vasotone of the rat mesenteric arteries. Importantly, the expression of NPW was decreased in the hypertensive rats. NPW-23 regulates ICa,L via GPR7, which is mediated by PLC/PKC signaling, and such a mechanism plays a role in modulating vascular myogenic tone, which may involve in the development of vascular hypertension.

  9. Novel asymptotic results on the high-order statistics of the channel capacity over generalized fading channels

    KAUST Repository

    Yilmaz, Ferkan

    2012-06-01

    The exact analysis of the higher-order statistics of the channel capacity (i.e., higher-order ergodic capacity) often leads to complicated expressions involving advanced special functions. In this paper, we provide a generic framework for the computation of the higher-order statistics of the channel capacity over generalized fading channels. As such, this novel framework for the higher-order statistics results in simple, closed-form expressions which are shown to be asymptotically tight bounds in the high signal-to-noise ratio (SNR) regime of a variety of fading environment. In addition, it reveals the existence of differences (i.e., constant capacity gaps in log-domain) among different fading environments. By asymptotically tight bound we mean that the high SNR limit of the difference between the actual higher-order statistics of the channel capacity and its asymptotic bound (i.e., lower bound) tends to zero. The mathematical formalism is illustrated with some selected numerical examples that validate the correctness of our newly derived results. © 2012 IEEE.

  10. Closure of multiple types of K+ channels is necessar to induce changes in renal vascular resistance in vivo in rats

    DEFF Research Database (Denmark)

    Sørensen, Charlotte Mehlin; Giese, Isaiah; Braunstein, Thomas Hartig

    2011-01-01

    Inhibition of K(+) channels might mediate renal vasoconstriction. As inhibition of a single type of K(+) channel caused minor or no renal vasoconstriction in vivo in rats, we hypothesized that several classes of K(+) channels must be blocked to elicit renal vasoconstriction. We measured renal blo...

  11. [Groin abscesses and vascular catastrophes in intravenous drug users--strategy and results].

    Science.gov (United States)

    Scheuerlein, H; Ruff, S; Haage, P; Zirngibl, H; Fraunhofer, S; Settmacher, U

    2008-02-01

    Drug addiction is a global medical and public health-care problem. Infections of the groin and fossa cubitalis are a common clinical problem in these patients. Severe vascular complications are rare but if they occur, therapy is difficult and requires emergency management and surgery because of bleeding problems. In a retrospective case series, we report on patients treated within an emergency setting in our hospital because of groin abscesses with vascular involvement between 2003 and 2006. The therapeutic concepts and results are reported and discussed in the context of a review of the international literature. We report on 4 patients with a long-standing history of i. v. drug abuse (average age 33, range 29-36 years). All were hepatitis C Ag positive and HIV negative. The general health and nutritional status were not compromised, all patients had one or more DVT in their medical history. In two cases, emergency surgery with revascularisation was necessary (after 2 days in one case and 4 weeks in the other) because of septic bleeding subsequent to abscess incision. Two patients underwent primary revascularisation because of pseudoaneurysms. The grafts were a saphenous vein patch and a superficial femoral artery patch in one and deep vein segments in two cases. In two cases, a sartorius muscle flap and VAC therapy were used to cover the defect. All patients survived, minor amputation became necessary in one case. Abscess excision and debridement have to be as complete as possible and primary revascularisation is the procedure of choice in cases of severe groin infection. In the case of large vessel involvement, abscess incision alone without revision of the vascular structures is dangerous because of subsequent complications like secondary ruptures. For this reason, these patients require intensive care and close monitoring. Successful treatment exclusively based on ligation is described in literature with regard to isolated lesions of the superficial or deep

  12. FPGA based, DSP integrated, 8-channel SIMCON, ver. 3.0. Initial results for 8-channel algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Giergusiewicz, W.; Koprek, W.; Jalmuzna, W.; Pozniak, K.T.; Romaniuk, R.S. [Warsaw Univ. of Technology (Poland). Inst. of Electronic Systems

    2005-07-01

    The paper describes design, construction and initial measurements of an eight channel electronic LLRF device predicted for building of the control system for the VUV-FEL accelerator at DESY (Hamburg). The device, referred in the paper to as the SIMCON 3.0 (from the SC cavity simulator and controller) consists of a 16 layer, VME size, PCB, a large FPGA chip (VirtexII-4000 by Xilinx), eight fast ADCs and four DACs (by Analog Devices). To our knowledge, the proposed device is the first of this kind for the accelerator technology in which there was achieved (the FPGA based) DSP latency below 200 ns. With the optimized data transmission system, the overall LLRF system latency can be as low as 500 ns. The SIMCON 3.0 sub-system was applied for initial tests with the ACC1 module of the VUV FEL accelerator (eight channels) and with the CHECHIA test stand (single channel), both at the DESY. The promising results with the SIMCON 3.0. encouraged us to enter the design of SIMCON 3.1. possessing 10 measurement and control channels and some additional features to be reported in the next technical note. SIMCON 3.0. is a modular solution, while SIMCON 3.1. will be an integrated board of the all-in-one type. Two design approaches - modular and all-in-one, after branching off in this version of the Simcon, will be continued. (orig.)

  13. Portal vein embolization using the Amplatzer vascular plug II. Preliminary results

    International Nuclear Information System (INIS)

    Libicher, Martin; Herbrik, M.; Poggenborg, J.; Bovenschulte, H.; Schwabe, H.; Stippel, D.

    2010-01-01

    Purpose: In this study we examined the feasibility of portal vein embolization (PVE) by using the Amplatzer Vascular Plug (AVP-II). We measured the time of vessel occlusion after plug deployment and changes in plug length and diameter within 4 weeks of PVE. Materials and Methods: in 10 consecutive patients (4 women, age 64 ± 10 yrs, 48 - 82 yrs) an ipsilateral PVE of the right portal vein was performed prior to intended hemihepatectomy. After embolization with microparticles, the right portal vein was occluded using an AVP-II. We measured the time of complete vessel occlusion by angiography. Follow-up with computed tomography (CT) was performed within 72h and after 4 weeks. Results: PVE was performed in all 10 patients without acute complications. Complete vessel occlusion was achieved in 9.7 ± 5.1 min (range 1 - 21 min). On follow-up CT we found enhanced arterial vascularization of the embolized liver segments in 5/5 patients within 72 hours and in 6/10 patients after 4 weeks. The plug showed a contraction of 20 ± 9% and a dilatation of 23 ± 13%. Thus, the AVP-II dilated to 94 ± 8% (78 - 100%) of its nominal diameter. The plug diameter was significantly larger in men compared to women (17 ± 1.7 mm vs. 14 ± 1.4 mm, p < 0.02). We did not observe any recanalization or migration of the device. The volume of the left liver lobe increased significantly by 27% (p < 0.001) after 4 weeks. Conclusion: PVE with the AVP-II is a feasible and effective method. The AVP-II can dilate within 4 weeks up to its nominal diameter dependent on the grade of oversizing. Dilatation of the diameter is associated with a shortening in length. (orig.)

  14. Coexpression of voltage-dependent calcium channels Cav1.2, 2.1a, and 2.1b in vascular myocytes

    DEFF Research Database (Denmark)

    Andreasen, Ditte; Friis, Ulla G; Uhrenholt, Torben R

    2006-01-01

    Voltage-dependent Ca2+ channels Cav1.2 (L type) and Cav2.1 (P/Q type) are expressed in vascular smooth muscle cells (VSMCs) and are important for the contraction of renal resistance vessels. In the present study we examined whether native renal VSMCs coexpress L-, P-, and Q-type Ca2+ currents...... microscopy revealed expression of both channels in all of the smooth muscle cells. Whole-cell patch clamp on single preglomerular VSMCs from mice showed L-, P-, and Q-type currents. Blockade of the L-type currents by calciseptine (20 nmol/L) inhibited 35.6+/-3.9% of the voltage-dependent Ca2+ current......-type and P-type channels inhibited 58.0+/-11.8%, and simultaneous inhibition of L-, P-, and Q-type channels led to blockade (88.7+/-5.6%) of the Ca2+ current. We conclude that aortic and renal preglomerular smooth muscle cells express L-, P-, and Q-type voltage-dependent Ca2+ channels in the rat and mouse....

  15. Channels Coordination Game Model Based on Result Fairness Preference and Reciprocal Fairness Preference: A Behavior Game Forecasting and Analysis Method

    OpenAIRE

    Ding, Chuan; Wang, Kaihong; Huang, Xiaoying

    2014-01-01

    In a distribution channel, channel members are not always self-interested, but altruistic in some conditions. Based on this assumption, this paper adopts a behavior game method to analyze and forecast channel members’ decision behavior based on result fairness preference and reciprocal fairness preference by embedding a fair preference theory in channel research of coordination. The behavior game forecasts that a channel can achieve coordination if channel members consider behavior elemen...

  16. Experimental test results of multi-channel test rig of T1 test section, 5

    International Nuclear Information System (INIS)

    Hino, Ryutaro; Takase, Kazuyuki; Miyamoto, Yoshiaki

    1990-09-01

    Channel blockage test on a fuel column of the high temperature engineering test reactor (HTTR) has been performed under the helium gas atmosphere at a high temperature and a high pressure in order to obtain safety data on flow rate and temperature distributions in the fuel column with the multi-channel test rig of the fuel stack test section (T 1 ) in HENDEL. In the test, one of 12 fuel channels was blockaded to 90% of flow area at the channel inlet. Experimental results showed that the helium gas flow rate in the blockaded channel was 28%∼33% lower than the average flow rate for Reynolds number from 2300 to 14000 in isothermal flow. When simulated fuel rods were heated, the flow rate in the blockaded channel did not decrease down in comparison with the isothermal flow. This is due to that the heat generated in the fuel rods conducts to the other fuel channels in graphite fuel blocks, so that accelerated pressure losses in the fuel channels change with helium gas temperatures. (author)

  17. Experimental studies in a single-phase parallel channel natural circulation system. Preliminary results

    International Nuclear Information System (INIS)

    Bodkha, Kapil; Pilkhwal, D.S.; Jana, S.S.; Vijayan, P.K.

    2016-01-01

    Natural circulation systems find extensive applications in industrial engineering systems. One of the applications is in nuclear reactor where the decay heat is removed by natural circulation of the fluid under off-normal conditions. The upcoming reactor designs make use of natural circulation in order to remove the heat from core under normal operating conditions also. These reactors employ multiple vertical fuel channels with provision of on-power refueling/defueling. Natural circulation systems are relatively simple, safe and reliable when compared to forced circulation systems. However, natural circulation systems are prone to encounter flow instabilities which are highly undesirable for various reasons. Presence of parallel channels under natural circulation makes the system more complicated. To examine the behavior of parallel channel system, studies were carried out for single-phase natural circulation flow in a multiple vertical channel system. The objective of the present work is to study the flow behavior of the parallel heated channel system under natural circulation for different operating conditions. Steady state and transient studies have been carried out in a parallel channel natural circulation system with three heated channels. The paper brings out the details of the system considered, different cases analyzed and preliminary results of studies carried out on a single-phase parallel channel system.

  18. Mid-term clinical results of tissue-engineered vascular autografts

    International Nuclear Information System (INIS)

    Matsumura, Goki; Shin'oka, Toshiharu; Hibino, Narutoshi; Saito, Satoshi; Sakamoto, Takahiko; Ichihara, Yuki; Hobo, Kyoko; Miyamoto, Shin'ka; Kurosawa, Hiromi

    2007-01-01

    Prosthetic and bioprosthetic materials currently in use lack growth potential and therefore must be repeatedly replaced in pediatric patients as they grow. Tissue engineering is a new discipline that offers the potential for creating replacement structures from autologous cells and biodegradable polymer scaffolds. In May 2000, we initiated clinical application of tissue-engineered vascular grafts seeded with cultured cells. However, cell culturing is time-consuming, and xenoserum must be used. To overcome these disadvantages, we began to use bone marrow cells, readily available on the day of surgery, as a cell source. Since September 2001, tissue-engineered grafts seeded with autologous bone marrow cells have been implanted in 44 patients. The patients or their parents were fully informed and had given consent to the procedure. A 3 to 10 ml/kg specimen of bone marrow was aspirated with the patient under general anesthesia before the skin incision. The polymer tube serving as a scaffold for the cells was composed of a copolymer of lactide and ε-caprolactone (50:50) which degrades by hydrolysis. Polyglycolic or poly-l-lactic acid woven fabric was used for reinforcement. Twenty-six tissue-engineered conduits and 19 tissue-engineered patches were used for the repair of congenital heart defects. The patients' ages ranged from 1 to 24 years (median 7.4 years). All patients underwent a catheterization study, CT scan, or both, for evaluation after the operation. There were 4 late deaths due to heart failure with or without multiple organ failure or brain bleeding in this series; these were unrelated to the tissue-engineered graft function. One patient required percutaneous balloon angioplasty for tubular graft-stenosis and 4 patients for the stenosis of the patch-shaped tissue engineered material. Two patients required re-do operation; one for recurrent pulmonary stenosis and another for a resulting R-L shunt after the lateral tunnel method. Kaplan-Meier analysis in

  19. Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

    KAUST Repository

    Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

  20. Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

    KAUST Repository

    Chaaban, Anas

    2016-10-26

    Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

  1. Injuries as a result of sports and vacation activities: Fractures with concomitant vascular injuries. Diagnosis and treatment concept

    International Nuclear Information System (INIS)

    Schlickewei, W.; Kuner, E.H.; Goetze, B.; Spillner, G.

    1989-01-01

    Extremity fractures with concomitant vascular injuries are surgical emergencies. Especially injuries of the upper extremities require a preoperative angiographic examination for the localization of the vascular lesion. In vascular lesions of the lower extremities a primary angiography is not necessary, if there is an opportunity for an intraoperative radiologic evaluation. In our traumatological department 104 patients were treated over the last 15 years with that combined injury. The concept of immediate stabilization of the fracture with simultaneous or postponed arterial repair has been proved to be appropriate. The fasziotomy as prophylactic procedure of a postischemic compartment syndrome is also a part of our concept during the last years. The late results in our mostly young patients depended on the degree of soft tissue damage and the time of ischemia. The often untreatable nerve lesions contributed to a loss of use of about 30% in the late courses. (orig.) [de

  2. Angiotensin Converting-Enzyme Inhibitors, Angiotensin Receptor Blockers, and Calcium Channel Blockers Are Associated with Prolonged Vascular Access Patency in Uremic Patients Undergoing Hemodialysis.

    Directory of Open Access Journals (Sweden)

    Fu-An Chen

    Full Text Available Vascular access failure is a huge burden for patients undergoing hemodialysis. Many efforts have been made to maintain vascular access patency, including pharmacotherapy. Angiotensin converting enzyme inhibitor (ACE-I, angiotensin receptor blocker (ARB, and calcium channel blocker (CCB are known for their antihypertensive and cardio-protective effects, however, their effects on long-term vascular access patency are still inconclusive.We retrospectively enrolled patients commencing maintenance hemodialysis between January 1, 2000, and December 31, 2006 by using National Health Insurance Research Database in Taiwan. Primary patency was defined as the date of first arteriovenous fistula (AVF or arteriovenous graft (AVG creation to the time of access thrombosis or any intervention aimed to maintain or re-establish vascular access patency. Cox proportional hazards models were used to adjust the influences of patient characteristics, co-morbidities and medications.Total 42244 patients were enrolled in this study, 37771 (89.4% used AVF, 4473 (10.6% used AVG as their first long term dialysis access. ACE-I, ARB, and CCB use were all associated with prolonged primary patency of AVF [hazard ratio (HR 0.586, 95% confidence interval (CI 0.557-0.616 for ACE-I use; HR 0.532, CI 0.508-0.556 for ARB use; HR 0.485, CI 0.470-0.501 for CCB use] and AVG (HR 0.557, CI 0.482-0.643 for ACE-I use, HR 0.536, CI 0.467-0.614 for ARB use, HR 0.482, CI 0.442-0.526 for CCB use.In our analysis, ACE-I, ARB, and CCB were strongly associated with prolonged primary patency of both AVF and AVG. Further prospective randomized studies are still warranted to prove the causality.

  3. Channel flow and trichloroethylene treatment in a partly iron-filled fracture: Experimental and model results

    Science.gov (United States)

    Cai, Zuansi; Merly, Corrine; Thomson, Neil R.; Wilson, Ryan D.; Lerner, David N.

    2007-08-01

    Technical developments have now made it possible to emplace granular zero-valent iron (Fe 0) in fractured media to create a Fe 0 fracture reactive barrier (Fe 0 FRB) for the treatment of contaminated groundwater. To evaluate this concept, we conducted a laboratory experiment in which trichloroethylene (TCE) contaminated water was flushed through a single uniform fracture created between two sandstone blocks. This fracture was partly filled with what was intended to be a uniform thickness of iron. Partial treatment of TCE by iron demonstrated that the concept of a Fe 0 FRB is practical, but was less than anticipated for an iron layer of uniform thickness. When the experiment was disassembled, evidence of discrete channelised flow was noted and attributed to imperfect placement of the iron. To evaluate the effect of the channel flow, an explicit Channel Model was developed that simplifies this complex flow regime into a conceptualised set of uniform and parallel channels. The mathematical representation of this conceptualisation directly accounts for (i) flow channels and immobile fluid arising from the non-uniform iron placement, (ii) mass transfer from the open fracture to iron and immobile fluid regions, and (iii) degradation in the iron regions. A favourable comparison between laboratory data and the results from the developed mathematical model suggests that the model is capable of representing TCE degradation in fractures with non-uniform iron placement. In order to apply this Channel Model concept to a Fe 0 FRB system, a simplified, or implicit, Lumped Channel Model was developed where the physical and chemical processes in the iron layer and immobile fluid regions are captured by a first-order lumped rate parameter. The performance of this Lumped Channel Model was compared to laboratory data, and benchmarked against the Channel Model. The advantages of the Lumped Channel Model are that the degradation of TCE in the system is represented by a first

  4. PRELIMINARY CLINICAL RESULTS WITH LIPOASPIRATE STROMAL VASCULAR CELL FRACTION IN TREATMENT OF PATIENTS WITH KNEE OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    E. Ya. Shevela

    2017-01-01

    Full Text Available The paper presents results of clinical application of autologous stromal-vascular fraction (SVF cells in patients with degenerative osteoarthritis (OA of the knee, grade II and III (Kellgren–Lawrence scale.We recruited six patients with knee OA (3 men and 3 women; median age 64 years with mean disease duration of 7 years. All the patients were administered a single intra-articular injection of autologous nucleated SVF cells at an average dose of 16.8±0.9 × 106 per joint (a total of 11 joints. The patients did not experience any serious side effects (allergic, toxic or inflammatory related to the knee injection. Patient surveys at 1 month after SVF administration revealed a decrease in the severity of pain, as measured by a visual analog scale (VAS and a specialized 100-point scale KOOS (subscale "pain" (p < 0.05 on both scales. Moreover, the patients reported improvement in the joint functions and quality of life related to affected joints on a KOOS scale (p < 0.05. These positive clinical changes persisted during 6 month follow up. Significant improvements were noted in ultrasound findings, with increased thickness of the cartilage layer at 3 months (in 73% of cases and at 6 months (in 82%. Our pilot study demonstrated the safety and tolerability of intra-articular injection of autologous SVF cells in patients with moderate to severe OA. The results obtained also indicate a significant antiinflammatory effect of autologous adipose tissue SVF cells, which is manifested at the early stages of cell therapy. Our further investigations will be focused on exploring the SVF stimulatory effects on regeneration of damaged joints.

  5. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar

    2005-04-01

    Full Text Available Background: Calcium channel blockers act at L-type calcium channels in cardiac and vascular smooth muscles by preventing calcium influx into cells with resultant decrease in vascular tone and cardiac inotropy, chronotropy and dromotropy. Poisoning with calcium channel blockers results in reduced cardiac output, bradycardia, atrioventricular block, hypotension and shock. The findings of hypotension and bradycardia should suggest poisoning with calcium channel blockers.Conclusions: Treatment includes immediate gastric lavage and whole-bowel irrigation in case of ingestion of sustainedrelease products. All patients should receive an activated charcoal orally. Specific treatment includes calcium, glucagone and insulin, which proved especially useful in shocked patients. Supportive care including the use of catecholamines is not always effective. In the setting of failure of pharmacological therapy transvenous pacing, balloon pump and cardiopulmonary by-pass may be necessary.

  6. Strain-free polished channel-cut crystal monochromators: a new approach and results

    Science.gov (United States)

    Kasman, Elina; Montgomery, Jonathan; Huang, XianRong; Lerch, Jason; Assoufid, Lahsen

    2017-08-01

    The use of channel-cut crystal monochromators has been traditionally limited to applications that can tolerate the rough surface quality from wet etching without polishing. We have previously presented and discussed the motivation for producing channel cut crystals with strain-free polished surfaces [1]. Afterwards, we have undertaken an effort to design and implement an automated machine for polishing channel-cut crystals. The initial effort led to inefficient results. Since then, we conceptualized, designed, and implemented a new version of the channel-cut polishing machine, now called C-CHiRP (Channel-Cut High Resolution Polisher), also known as CCPM V2.0. The new machine design no longer utilizes Figure-8 motion that mimics manual polishing. Instead, the polishing is achieved by a combination of rotary and linear functions of two coordinated motion systems. Here we present the new design of C-CHiRP, its capabilities and features. Multiple channel-cut crystals polished using the C-CHiRP have been deployed into several beamlines at the Advanced Photon Source (APS). We present the measurements of surface finish, flatness, as well as topography results obtained at 1-BM of APS, as compared with results typically achieved when polishing flat-surface monochromator crystals using conventional polishing processes. Limitations of the current machine design, capabilities and considerations for strain-free polishing of highly complex crystals are also discussed, together with an outlook for future developments and improvements.

  7. Response of Vascular Plant Communities to Harvest in Southern Appalachian Mixed-Oak Forests: Two-Year Results

    Science.gov (United States)

    Bryan W. Wender; Sharon M. Hood; David W. Smith; Shepard M. Zedaker; David L. Loftis

    1999-01-01

    A long-term study has been established to monitor the effects of seven silvicultural prescriptions on vascular flora community attributes. Treatments include a control, understory vegetation control, group selection, two levels of shelterwoods, leave-tree, and clearcut. Second growing season. post-treatment results are compared to pre-harvest values for residual~...

  8. The Effect of Vascular Neuropathology on Late-life Cognition: Results from the SMART Project.

    Science.gov (United States)

    Kryscio, R J; Abner, E L; Nelson, P T; Bennett, D; Schneider, J; Yu, L; Hemmy, L S; Lim, K O; Masaki, K; Cairns, N; Xiong, C; Woltjer, R; Dodge, H H; Tyas, S; Fardo, D W; Lou, W; Wan, L; Schmitt, F A

    2016-06-01

    Cerebral vascular pathology may contribute to cognitive decline experienced by some elderly near death. Given evidence for mixed neuropathologies in advanced age, preventing or reducing cerebrovascular burden in late life may be beneficial. To correlate measures of cerebral vascular pathology with cognitive trajectories. Observational study. A cohort of 2,274 individuals who came to autopsy at a mean age of 89.3 years and 82 percent of whom had at least two cognitive assessments within the last six years of life was compiled from six centers conducting longitudinal studies. For each cognitive domain: immediate and delayed memory, language, and naming, three trajectories were examined: good, intermediate, and poor cognition. The probability of a participant belonging to each trajectory was associated with measures of cerebral vascular pathology after adjustment for demographics, APOE, and Alzheimer neuropathology. A large proportion of the cohort (72-94%) experienced good or intermediate cognition in the four domains examined. The presence of arteriolosclerosis and the presence of lacunar infarcts doubled the odds of belonging to the poor cognitive trajectory for language when compared to the good trajectory. The presence of lacunar infarcts increased the odds of an intermediate or poor trajectory for immediate and delayed recall while the presence of large artery infarcts increased the odds of poor trajectories for all four cognitive domains examined. Microinfarcts and cerebral amyloid angiopathy had little effect on the trajectories. Indicators of cerebral vascular pathology act differently on late life cognition.

  9. Brain Perivascular Spaces as Biomarkers of Vascular Risk: Results from the Northern Manhattan Study.

    Science.gov (United States)

    Gutierrez, J; Elkind, M S V; Dong, C; Di Tullio, M; Rundek, T; Sacco, R L; Wright, C B

    2017-05-01

    Dilated perivascular spaces in the brain are associated with greater arterial pulsatility. We hypothesized that perivascular spaces identify individuals at higher risk for systemic and cerebral vascular events. Stroke-free participants in the population-based Northern Manhattan Study had brain MR imaging performed and were followed for myocardial infarction, any stroke, and death. Imaging analyses distinguished perivascular spaces from lesions presumably ischemic. Perivascular spaces were further subdivided into lesions with diameters of ≤3 mm (small perivascular spaces) and >3 mm (large perivascular spaces). We calculated relative rates of events with Poisson models and hazard ratios with Cox proportional models. The Northern Manhattan Study participants who had MR imaging data available for review ( n = 1228; 59% women, 65% Hispanic; mean age, 71 ± 9 years) were followed for an average of 9 ± 2 years. Participants in the highest tertile of the small perivascular space score had a higher relative rate of all deaths (relative rate, 1.38; 95% CI, 1.01-1.91), vascular death (relative rate, 1.87; 95% CI, 1.12-3.14), myocardial infarction (relative rate, 2.08; 95% CI, 1.01-4.31), any stroke (relative rate, 1.79; 95% CI, 1.03-3.11), and any vascular event (relative rate, 1.74; 95% CI, 1.18-2.56). After we adjusted for confounders, there was a higher risk of vascular death (hazard ratio, 1.06; 95% CI, 1.01-1.11), myocardial infarction (hazard ratio, 2.22; 95% CI, 1.12-4.42), and any vascular event (hazard ratio, 1.04; 95% CI, 1.01-1.08) with higher small perivascular space scores. In this multiethnic, population-based study, participants with a high burden of small perivascular spaces had increased risk of vascular events. By gaining pathophysiologic insight into the mechanism of perivascular space dilation, we may be able to propose novel therapies to better prevent vascular disorders in the population. © 2017 by American Journal of Neuroradiology.

  10. Comparison of the effects of the K(+)-channel openers cromakalim and minoxidil sulphate on vascular smooth muscle.

    Science.gov (United States)

    Wickenden, A. D.; Grimwood, S.; Grant, T. L.; Todd, M. H.

    1991-01-01

    1 The actions of the potassium channel openers, cromakalim and minoxidil sulphate, were compared in a range of isolated blood vessel preparations. 2 Cromakalim and minoxidil sulphate inhibited spontaneous mechanical activity of the guinea-pig portal vein and relaxed the noradrenaline precontracted rat aorta with similar potency. In contrast, minoxidil sulphate was less potent than cromakalim in inhibiting spontaneous activity in the rat portal vein and was essentially inactive in the noradrenaline precontracted rat mesenteric artery and rabbit aorta. 3 Minoxidil sulphate did not antagonize the effects of cromakalim in the rabbit aorta indicating it was not acting as a partial 'agonist'. 4 Charybdotoxin, noxiustoxin and rubidium failed to discriminate between cromakalim and minoxidil sulphate indicating that the apparently selective effects of minoxidil sulphate were not mediated by either Ca(2+)-activated potassium channels, delayed rectifiers or rubidium impermeable potassium channels. 5 Glibenclamide antagonized the effects of cromakalim in an apparently competitive manner whereas the effects of minoxidil sulphate were antagonized in a non-competitive manner. The involvement of subtypes of ATP-sensitive potassium channels is discussed. PMID:1878752

  11. Jellyfish Envenomation Resulting In Vascular Insufficiency And Neurogenic Injury of Upper Limb

    Directory of Open Access Journals (Sweden)

    Choong CYL

    2015-11-01

    Full Text Available Following a week after a jellyfish sting, a young man presented with regional cyanosis and threat of distal gangrene secondary to vascular spasm in the forearm. The patient also suffered from transient paresis and numbness of the affected upper limb. Contrasted imaging revealed unopacified vessels in the distal forearm and worsening swelling warranted emergency surgical fasciotomy for impending compartment syndrome. This case highlights the occurrence of jellyfish envenomation and the need for early treatment.

  12. Episodic vertigo resulting from vascular risk factors, cervical spondylosis and head rotation: Two case reports

    OpenAIRE

    Owolabi, Mayowa O; Ogah, Okechukwu S; Ogunniyi, Adesola

    2007-01-01

    Background Vascular risk factors predispose to vertebrobasilar ischemia. Cervical osteophytes can impinge on the vertebral artery causing mechanical occlusion during head turning. Presentation with vertigo in such instances is a common finding. Case presentation A patient with obesity, hyperlipidemia, hypertension, cervical spondylosis, and vertigo triggered by head rotation is presented. She responded to antihypertensive and lipid-lowering drugs, vestibular sedative and application of cervic...

  13. Cells exposed to a huntingtin fragment containing an expanded polyglutamine tract show no sign of ion channel formation: results arguing against the ion channel hypothesis

    DEFF Research Database (Denmark)

    Nørremølle, Anne; Grunnet, Morten; Hasholt, Lis

    2003-01-01

    Ion channels formed by expanded polyglutamine tracts have been proposed to play an important role in the pathological processes leading to neurodegeneration in Huntington's disease and other CAG repeat diseases. We tested the capacity of a huntingtin fragment containing an expanded polyglutamine...... in the currents recorded in any of the two expression systems, indicating no changes in ion channel activity. The results therefore argue against the proposed hypothesis of expanded polyglutamines forming ion channels....

  14. Geomorphic changes resulting from floods in reconfigured gravel-bed river channels in Colorado, USA

    Science.gov (United States)

    Elliott, J.G.; Capesius, J.P.

    2009-01-01

    Geomorphic changes in reconfi gured reaches of three Colorado rivers in response to floods in 2005 provide a benchmark for "restoration" assessment. Sedimententrainment potential is expressed as the ratio of the shear stress from the 2 yr, 5 yr, 10 yr, and 2005 floods to the critical shear stress for sediment. Some observed response was explained by the excess of flood shear stress relative to the resisting force of the sediment. Bed-load entrainment in the Uncompahgre River and the North Fork Gunnison River, during 4 and 6 yr floods respectively, resulted in streambed scour, streambed deposition, lateral-bar accretion, and channel migration at various locations. Some constructed boulder and log structures failed because of high rates of bank erosion or bed-material deposition. The Lake Fork showed little or no net change after the 2005 flood; however, this channel had not conveyed floods greater than the 2.5 yr flood since reconfi guration. Channel slope and the 2 yr flood, a surrogate for bankfull discharge, from all three reconfi gured reaches plotted above the Leopold and Wolman channel-pattern threshold in the "braided channel" region, indicating that braiding, rather than a single-thread meandering channel, and midchannel bar formation may be the natural tendency of these gravel-bed reaches. When plotted against a total stream-power and median-sediment-size threshold for the 2 yr flood, however, the Lake Fork plotted in the "single-thread channel" region, the North Fork Gunnison plotted in the " multiplethread" region, and the Uncompahgre River plotted on the threshold. All three rivers plotted in the multiple-thread region for floods of 5 yr recurrence or greater. ?? 2009 Geological Society of America.

  15. The importance of complete follow-up for results after femoro-infrapopliteal vascular surgery

    DEFF Research Database (Denmark)

    Jensen, L P; Nielsen, O M; Schroeder, T V

    1996-01-01

    intervals and all data have been recorded prospectively in a vascular registry. As part of a randomised trial on adjuvant medication in femorocrural bypass surgery, 102 patients, operated on between 1990 and 1992 were independently and simultaneously monitored. This subgroup was examined at 3 and 12 months...... is lost to follow-up, since failure to examine the patient for any reason may be related to the patients health. In addition to the number of patients at risk, it is suggested, that life-table plots should be supplemented with information on the number of patients lost to follow-up....

  16. Novel asymptotic results on the high-order statistics of the channel capacity over generalized fading channels

    KAUST Repository

    Yilmaz, Ferkan; Alouini, Mohamed-Slim

    2012-01-01

    The exact analysis of the higher-order statistics of the channel capacity (i.e., higher-order ergodic capacity) often leads to complicated expressions involving advanced special functions. In this paper, we provide a generic framework

  17. Results and technical problems of therapeutic vascular embolization with special reference to the use of spirals

    International Nuclear Information System (INIS)

    Grosse-Vorholt, R.; Zeitler, E.

    1980-01-01

    31 therapeutic vascular embolizations were performed: 4 for osteolytic lesions; 24 for renal tumors and 3 for malignant hypertension in 3 patients with chronic pyelonephritis and corresponding bilateral kidney shrinkage with the kidneys left in the patients (-one patient being put on chronic dialysis and 2 having undergone renal transplantation). Opacifying chemical substances (Ethibloc) and nonopacifying chemical substances (Fibrospum, Butyl-2-Cyanoacrylat) were sometimes used for embolization; but most of the time, metal spiral (licenced by Cianturco) were taken, because of the following advantages: Their insertion is simple and easily controlled by fluoroscopy; they cause less pain, and they induce progressive thrombosis in the embolised artery. In cases, however, where catheterisation is difficult or impossible (narrow lumen/collaterals), embolization with chemical substances has to be done in addition to that by spiral. (orig.) [de

  18. The shallow-water Asellota (Crustacea: Isopoda from the Beagle Channel: Preliminary taxonomic and zoogeographical results

    Directory of Open Access Journals (Sweden)

    Brenda Lía Doti

    2005-12-01

    Full Text Available The shallow-water Asellota from the Beagle Channel were investigated, based on material collected at four localities in 2001-2002. A total of 3,124 asellotes were sorted, and three new species and 12 new records of distribution were reported. The Paramunnidae showed the highest species diversity and abundance (11 species and 1,463 specimens. The present research raises the number of species known from the Beagle Channel to 23; of these, 16 were previously reported from the Magellan Straits, representing 69% of similarity. Based on the present results and published data, the faunistic affinities for the shallow-water Asellota was 30% between the Magellan region and the Scotia Arc, and 26% between the Magellan region and the Antarctic Peninsula.

  19. Quality of life after TIA and stroke: ten-year results of the Oxford Vascular Study.

    Science.gov (United States)

    Luengo-Fernandez, Ramon; Gray, Alastair M; Bull, Linda; Welch, Sarah; Cuthbertson, Fiona; Rothwell, Peter M

    2013-10-29

    To evaluate the 5-year impact of stroke and TIA on utility and quality-adjusted survival. TIA and stroke patients from a UK population-based study (Oxford Vascular Study) were recruited from 2002 to 2007, and followed up until 2012. Quality of life was assessed over 5 years using the EQ-5D (EuroQol-5 Dimensions), with responses converted into utilities ranging from -0.59 (worse than death) to 1 (perfect health), using UK population valuations. Utilities for stroke and TIA patients were compared with those in matched controls obtained from the 2006 Health Survey for England. Five-year quality-adjusted life years were estimated by combining utility and survival information. Four hundred forty TIA and 748 stroke patients were ascertained and included. Utility remained constant at approximately 0.78 over the 5 years after TIA. Utility improved from 0.64 one month after stroke to 0.70 at 6 months (p = 0.006), remaining at approximately 0.70 thereafter. Matched controls had considerably higher utility levels than stroke/TIA patients (0.85, p TIA and 2.21 (2.15-2.37) after stroke, varying considerably by severity (minor: 2.94; moderate: 1.65; and severe: 0.70). Quality-adjusted survival is low over the 5 years after stroke and TIA, with severity and recurrent stroke being major predictors. There remains considerable scope for improvements in acute treatment and secondary prevention to improve the quality of life after TIA and stroke.

  20. Effectiveness of quantitative MAA SPECT/CT for the definition of vascularized hepatic volume and dosimetric approach: phantom validation and clinical preliminary results in patients with complex hepatic vascularization treated with yttrium-90-labeled microspheres.

    Science.gov (United States)

    Garin, Etienne; Lenoir, Laurence; Rolland, Yan; Laffont, Sophie; Pracht, Marc; Mesbah, Habiba; Porée, Philippe; Ardisson, Valérie; Bourguet, Patrick; Clement, Bruno; Boucher, Eveline

    2011-12-01

    The goal of this study was to assess the use of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) analysis for vascularized volume measurements in the use of the yttrium-90-radiolabeled microspheres (TheraSphere). A phantom study was conducted for the validation of SPECT/CT volume measurement. SPECT/CT quantitative analysis was used for the measurement of the volume of distribution of the albumin macroaggregates (MAA; i.e., the vascularized volume) in the liver and the tumor, and the total activity contained in the liver and the tumor in four consecutive patients presenting with a complex liver vascularization referred for a treatment with TheraSphere. SPECT/CT volume measurement proved to be accurate (mean error <7%) and reproducible (interobserver concordance 0.99). For eight treatments, in cases of complex hepatic vascularization, the hepatic volumes based on angiography and CT led to a relative overestimation or underestimation of the vascularized hepatic volume by 43.2 ± 32.7% (5-87%) compared with SPECT/CT analyses. The vascularized liver volume taken into account calculated from SPECT/CT data, instead of angiography and CT data, results in modifying the activity injected for three treatments of eight. Moreover, quantitative analysis of SPECT/CT allows us to calculate the absorbed dose in the tumor and in the healthy liver, leading to doubling of the injected activity for one treatment of eight. MAA SPECT/CT is accurate for volume measurements. It provides a valuable contribution to the therapeutic planning of patients presenting with complex hepatic vascularization, in particular for calculating the vascularized liver volume, the activity to be injected and the absorbed doses. Studies should be conducted to assess the role of quantitative MAA/SPECT CT in therapeutic planning.

  1. In situ replacement of infected vascular prosthesis with fresh arterial homograft: Early and long-term results in 18 patients

    Directory of Open Access Journals (Sweden)

    Pejkić Siniša

    2013-01-01

    Full Text Available Introduction. Graft infection is rightly considered one of the severest complications of vascular reconstruction. Treatment is non­standardized and associated with high mortality and morbidity rates. The choice of therapeutic modality depends upon variety of factors. One increasingly used option is in situ replacement of the infected prosthesis with the arterial allograft. Objective. The aim of this prospective nonrandomized study was to evaluate the effectiveness and durability of fresh arterial allograft as in situ substitute for the infected vascular prosthesis. Methods. During period of 2002-2005, 18 patients with the synthetic vascular graft infection underwent partial or complete prosthesis removal and secondary in situ reconstruction using the fresh arterial allograft, preserved under hypothermic conditions in buffered saline solution with an addition of antibiotics. Results. In 14 male and 4 female patients, meanaged 62 years, 8 aortic and 10 peripheral arterial infected prostheses were partially or completely replaced with the allograft. Operative mortality was 27.8% and amputation rate was 22.2%. Systemic sepsis at initial presentation and highly virulent nature of causative microorganisms were identified as significant negative prognostic factors (χ² test, p<0.05. During the long­term follow­up (mean 47 months, allograft aneurysm developed in three patients, requiring allograft explantation, followed in two cases by tertiary prosthetic reconstruction. Conclusion. Substitution of the infected prosthesis with the arterial allograft could be successful if used selectively - for less virulent and localized infections of extracavitary grafts. Close follow­up is mandatory for timely diagnosis of late homograft lesions and its eventual replacement with more durable prosthetic material.

  2. Prediction of Thorough QT study results using action potential simulations based on ion channel screens.

    Science.gov (United States)

    Mirams, Gary R; Davies, Mark R; Brough, Stephen J; Bridgland-Taylor, Matthew H; Cui, Yi; Gavaghan, David J; Abi-Gerges, Najah

    2014-01-01

    Detection of drug-induced pro-arrhythmic risk is a primary concern for pharmaceutical companies and regulators. Increased risk is linked to prolongation of the QT interval on the body surface ECG. Recent studies have shown that multiple ion channel interactions can be required to predict changes in ventricular repolarisation and therefore QT intervals. In this study we attempt to predict the result of the human clinical Thorough QT (TQT) study, using multiple ion channel screening which is available early in drug development. Ion current reduction was measured, in the presence of marketed drugs which have had a TQT study, for channels encoded by hERG, CaV1.2, NaV1.5, KCNQ1/MinK, and Kv4.3/KChIP2.2. The screen was performed on two platforms - IonWorks Quattro (all 5 channels, 34 compounds), and IonWorks Barracuda (hERG & CaV1.2, 26 compounds). Concentration-effect curves were fitted to the resulting data, and used to calculate a percentage reduction in each current at a given concentration. Action potential simulations were then performed using the ten Tusscher and Panfilov (2006), Grandi et al. (2010) and O'Hara et al. (2011) human ventricular action potential models, pacing at 1Hz and running to steady state, for a range of concentrations. We compared simulated action potential duration predictions with the QT prolongation observed in the TQT studies. At the estimated concentrations, simulations tended to underestimate any observed QT prolongation. When considering a wider range of concentrations, and conventional patch clamp rather than screening data for hERG, prolongation of ≥5ms was predicted with up to 79% sensitivity and 100% specificity. This study provides a proof-of-principle for the prediction of human TQT study results using data available early in drug development. We highlight a number of areas that need refinement to improve the method's predictive power, but the results suggest that such approaches will provide a useful tool in cardiac safety

  3. Backscattering study and theoretical investigation of planar channeling processes. I. Experimental results

    International Nuclear Information System (INIS)

    Abel, F.; Amsel, G.; Bruneaux, M.; Cohen, C.; L'Hoir, A.

    1975-01-01

    Backscattering experiments in planar channeling have been performed on iron single crystals with 1.9-MeV 4 He beams; these conditions having been chosen for optimal study of the structure of the spectra. Both for the (110) and (100) planes five equally spaced yield maxima are clearly resolved, the maxima damping out at lower energies. Spectra were also registered at various angles of incidence phi 0 with respect to the planes. Yield maxima are observed up to values of phi 0 twice the half-width at half-minimum psi 1 / 2 of an angular scan across the plane psi 1 / 2 =18' for the (110) plane. Except for the first two peaks, these maxima have the same spacing as in the aligned spectrum. They appear to be due to particles belonging to a well-defined transverse energy interval. The mean stopping power for these particles is close to the random stopping power and the mean half-wavelength of their oscillating trajectories in the planar channels calculated from the results is lambda=380 A for the (110) plane and lambda=320 A for the (100) plane. For phi 0 >1.2psi 1 / 2 , the yield on the first maximum is greater than the random yield, reaching approx.1.6 times the latter for 1.4psi 1 / 2 0 1 / 2 . The shoulder effect in the angular scans, as observed for various depths, is clearly related to the yield maxima and hence depends strongly on the position and width of the depth interval chosen. The meaning and validity of the assumption of statistical equilibrium for planar channeled particles are discussed in light of the results

  4. Channel Bow in Boiling Water Reactors - Hot Cell Examination Results and Correlation to Measured Bow

    International Nuclear Information System (INIS)

    Mahmood, S.T.; Lin, Y.P.; Dubecky, M.A.; Edsinger, K.; Mader, E.V.

    2007-01-01

    An increase in frequency of fuel channel-control blade interference has been observed in Boiling Water Reactors (BWR) in recent years. Many of the channels leading to interference were found to bow towards the control blade in a manner that was inconsistent with the expected bow due to other effects. The pattern of bow appeared to indicate a new channel bow mechanism that differed from the predominant bow mechanism caused by differential growth due to fast-fluence gradients. In order to investigate this new type of channel bow, coupons from several channels with varying degrees of bow were returned to the GE Vallecitos Nuclear Center (VNC) for Post-Irradiation Examination (PIE). This paper describes the characteristics of channel corrosion and hydrogen pickup observed, and relates the observations to the channel exposure level, control history, and measured channel bow. The channels selected for PIE had exposures in the range of 36-48 GWd/MTU and covered a wide range of measured bow. The coupons were obtained at 4 elevations from opposing channel sides adjacent and away from the control blade. The PIE performed on these coupons included visual examination, metallography, and hydrogen concentration measurements. A new mechanism of control-blade shadow corrosion-induced channel bow was found to correlate with differences in the extent of corrosion and corresponding differences in the hydrogen concentration between opposite sides of the channels. The increased corrosion on the control blade sides was found to be dependent on the level of control early in the life of the channel. The contributions of other potential factors leading to increased channel bow and channel-control blade interference are also discussed in this paper. (authors)

  5. New Results on Single-Channel Speech Separation Using Sinusoidal Modeling

    DEFF Research Database (Denmark)

    Mowlaee, Pejman; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2011-01-01

    We present new results on single-channel speech separation and suggest a new separation approach to improve the speech quality of separated signals from an observed mix- ture. The key idea is to derive a mixture estimator based on sinusoidal parameters. The proposed estimator is aimed at finding...... mixture estimator used in binary masks and the Wiener filtering approach, it is observed that the proposed method achieves an acceptable perceptual speech quality with less cross- talk at different signal-to-signal ratios. Moreover, the method is independent of pitch estimates and reduces the computational...... complexity of the separation by replacing the short-time Fourier transform (STFT) feature vectors of high dimensionality with sinusoidal feature vectors. We report separation results for the proposed method and compare them with respect to other benchmark methods. The improvements made by applying...

  6. Results of a Peripheral Cutting Balloon Prospective Multicenter European Registry in Hemodialysis Vascular Access

    International Nuclear Information System (INIS)

    Peregrin, Jan H.; Rocek, Miloslav

    2007-01-01

    Purpose. To report initial experience with the Peripheral Cutting Balloon (PCB) in treatment of failing hemodialysis shunts. Methods. A total of 190 patients (95 men, 95 women; average age 64.4 ± 11.9 years, range 32-87 years) who were treated with the PCB for pressure-resistant stenosis, restenosis or failed percutaneous transluminal angioplasty (PTA) in the venous limb of an arteriovenous shunt were followed in seven European centers using a simple registry. The group consisted of 109 de novo lesions (57%) and 79 restenotic lesions (43%). Results. Technical success was achieved in 88.9% of cases. Primary patency was as follows (the results for whole group and simultaneous results for de novo lesions and restenoses are presented): 1 month (140 patients followed): 94%, 98%, and 93%; 3 months (116 patients followed): 93%, 98%, and 92%; 6 months (40 patients followed): 85%, 92%, and 79%; 12 months (27 patients followed): 74%, 87%, and 48%. No complication occurred. Patients experienced an equal or lower level of pain during the procedure compared with conventional PTA. Conclusion. The PCB proved to be successful in dilating pressure-resistant stenoses. We cannot conclude whether PCB angioplasty can lower the restenosis rate in hemodialysis access lesions, but the long-term patency for de novo lesions is high. A further randomized study is advisable

  7. Occult CSF flow disturbance of patients with Alzheimer type dementia and vascular dementia; Results from Iotrolan CT-cisternography

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Kazuhiko; Sugita, Yasuko; Funaki, Chiaki [Nagoya Univ. (Japan). Faculty of Medicine; and others

    1994-04-01

    We report results of Iotrolan CT-cisternography on 41 demented patients (13 males and 28 females) to find 'occult normal pressure hydrocephalus'. These patients were suspected to have CSF flow disturbance from clinical symptoms and simple brain CT scan findings. Their average age, duration of dementia, and score of Hasegawa's dementia scale (HDS) were 76.2 years, 5.9 years, 9.5/32.5,respectively. Before performing CT-cisternography, clinical diagnosis for their dementia were vascular dementia in 18 patients. Alzheimer type dementia in 12, suspect of NPH in 5, and other diagnoses in 6. From the results of cisternography, we found 13 patients with CSF flow disturbance (contrast material remained in the ventricle more than 48 hours after injection), and 17 patients with normal CSF flow. The former showed lower scores of HDS, higher urinary incontinence scores and smaller areas of the interhemispheric fissure on CT scan than the latter. But the former showed no significant difference from the latter in the average age, duration of dementia and width of the ventricles. (author).

  8. Anti-vascular endothelial growth factors for choroidal neovascularization secondary to choroidal osteoma: Long-term results

    Directory of Open Access Journals (Sweden)

    T Lekha

    2015-01-01

    Full Text Available Choroidal osteoma is an uncommon benign osseous intraocular tumor typically seen unilaterally in young women. Visual loss can occur due to choroidal neovascularization (CNV complicating osteoma. We report a rare case of bilateral choroidal osteoma with secondary CNV in a young male and the long-term results following anti-vascular endothelial growth factor (VEGF therapy. A 30-year-old male with history of defective vision in both eyes since several years and recent worsening in the right eye (RE since 2 months was found to have bilateral macular osteoma with CNV in the RE based on clinical evaluation, fluorescein angiography, optical coherence tomography, and ultrasonography. Intravitreal injection of ranibizumab at monthly intervals for three doses resulted in resolution of CNV and remained stable for 5 years. Recurrent CNV detected 6 years later responded to an injection of intravitreal bevacizumab and has remained stable till date. Anti-VEGF therapy stabilized the secondary CNV in our patient for 7 years with satisfactory structural and functional outcome, demonstrating the long-term efficacy of this modality of treatment.

  9. Long-term results of repeated anti-vascular endothelial growth factor therapy in eyes with retinal pigment epithelial tears.

    Science.gov (United States)

    Moreira, Carlos A; Arana, Luis A; Zago, Rommel J

    2013-02-01

    To evaluate the long-term results of retinal pigment epithelium tears in eyes treated with repeated anti-vascular endothelial growth factor (VEGF) therapy. Five patients with retinal pigment epithelial tears (without foveal center involvement) after anti-VEGF injection were studied retrospectively. Mean follow-up time was 52 months, with measurements of visual acuity and evaluation of macular findings by angiography and optical coherence tomography during this period. All eyes had a persistent submacular neovascular membrane 30 days after the tear. An anti-VEGF drug was reinjected until the membranes stopped leaking. The mean initial visual acuity immediately after the tear was 20/160, and the mean final visual acuity was 20/60. The number of anti-VEGF reinjections varied from two to eight during the follow-up period. Long-term optical coherence tomography analysis showed reduced fluid and remodeling of the torn retinal pigment epithelium. Long-term visual results with repeated anti-VEGF therapy are not as devastating as suggested previously. Visual acuity and metamorphopsia improve with time as long as the neovascular membrane is inactive. Optical coherence tomography changes in the macular area reflect the visual acuity improvement.

  10. Retinal vascular pathology risk development in the irradiated at different ages as a result if Chornobyl NPP accident

    International Nuclear Information System (INIS)

    Fedyirko, P.A.; Babenko, T.F.; Doryichevs'ka, R.Yu.; Gar'kava, N.A.

    2015-01-01

    The object of the study was the state of the retinal vessels in 2,531 persons (1,948 evacuated from the city of Pripyat under the age of 20 and 583 exposed to radiation in utero as a result of the Chornobyl NPP disaster. The results of standardized ophthalmic examination conducted from 1993 to 2000 within the framework of Clinical and epidemiological registry are used for the analysis. The evacuees were subdivided into different age groups of the exposed to radiation. The cohort of control group formed corresponding age groups of the unirradiated control. Statistical analysis of the survey results was carried out using the free trial version of ''Open Epi 2.2.1'' software package. The results obtained revealed a significant prevalence of retinal vessels pathology in all groups. The difference in angiopathy prevalence in exposed in utero persons was significant compared to age control. The prevalence of retinal vascular pathology was also significantly higher in all groups of evacuees. Angiopathy prevalence was higher in the group exposed in utero and at the age of 8-12 years, and in the group of people who were exposed at the age of 4-7 years, the risk of angiopathy was lower. It is proved that the occurrence of distant radiation effects mainly depends on the age at which a person has undergone irradiation. It should be noted that all the other conditions were approximately the same. If working conditions of the persons who were exposed in utero or were aged 8 to 20 years when the Chornobyl disaster happened are connected with occupational radiation exposure it is necessary to take additional preventive measures

  11. RETINAL VASCULAR PATHOLOGY RISK DEVELOPMENT IN THE IRRADIATED AT DIFFERENT AGES AS A RESULT OF CHERNOBYL NPP ACCIDENT.

    Science.gov (United States)

    Fedirko, P A; Babenko, T F; Dorichevska, R Yu; Garkava, N A

    2015-12-01

    To assess the relationship between the age at which a person undergoes radiation exposure and risk of developing eye lesions (case study of the retinal angiopathy prevalence). The object of the study was the state of the retinal vessels in 2,531 persons (1,948 evacuated from the city of Pripyat under the age of 20 and 583 exposed to radiation in utero as a result of the Chernobyl NPP disaster. The results of standardized ophthalmic examination conducted from 1993 to 2000 within the framework of Clinical and epidemiological registry are used for the analysis. The evacuees were subdivided into different age groups of the exposed to radiation. The cohort of control group formed corresponding age groups of the unirradiated control. Statistical analysis of the survey results was carried out using the free trial version of «Open Epi 2.2.1» software package. The results obtained revealed a significant prevalence of retinal vessels pathology in all groups. The difference in angiopathy prevalence in exposed in utero persons was significant compared to age-control. The prevalence of retinal vascular pathology was also significantly higher in all groups of evacuees. Angiopathy prevalence was higher in the group exposed in utero and at the age of 8-12 years, and in the group of people who were exposed at the age of 4-7 years, the risk of angiopathy was lower. It is proved that the occurrence of distant radiation effects mainly depends on the age at which a person has undergone irradiation. It should be noted that all the other conditions were approximately the same. If working conditions of the persons who were exposed in utero or were aged 8 to 20 years when the Chernobyl disaster happened are connected with occupational radiation exposure it is necessary to take additional preventive measures. P. А. Fedirko, T. F. Babenko, R. Yu. Dorichevska, N. А. Garkava.

  12. Vascular smooth muscle cells express the alpha(1A) subunit of a P-/Q-type voltage-dependent Ca(2+)Channel, and It is functionally important in renal afferent arterioles

    DEFF Research Database (Denmark)

    Hansen, Pernille B. Lærkegaard; Jensen, Boye L.; Andreasen, D

    2000-01-01

    In the present study, we tested whether the alpha(1A) subunit, which encodes a neuronal isoform of voltage-dependent Ca(2+) channels (VDCCs) (P-/Q-type), was present and functional in vascular smooth muscle and renal resistance vessels. By reverse transcription-polymerase chain reaction...... preglomerular resistance vessels and aorta, as well as mesangial cells, and that P-type VDCCs contribute to Ca(2+) influx in aortic and renal VSMCs and are involved in depolarization-mediated contraction in renal afferent arterioles....

  13. The effect of signal variability on the histograms of anthropomorphic channel outputs: factors resulting in non-normally distributed data

    Science.gov (United States)

    Elshahaby, Fatma E. A.; Ghaly, Michael; Jha, Abhinav K.; Frey, Eric C.

    2015-03-01

    Model Observers are widely used in medical imaging for the optimization and evaluation of instrumentation, acquisition parameters and image reconstruction and processing methods. The channelized Hotelling observer (CHO) is a commonly used model observer in nuclear medicine and has seen increasing use in other modalities. An anthropmorphic CHO consists of a set of channels that model some aspects of the human visual system and the Hotelling Observer, which is the optimal linear discriminant. The optimality of the CHO is based on the assumption that the channel outputs for data with and without the signal present have a multivariate normal distribution with equal class covariance matrices. The channel outputs result from the dot product of channel templates with input images and are thus the sum of a large number of random variables. The central limit theorem is thus often used to justify the assumption that the channel outputs are normally distributed. In this work, we aim to examine this assumption for realistically simulated nuclear medicine images when various types of signal variability are present.

  14. Rapid diagnosis and treatment of TIA results in low rates of stroke, myocardial infarction and vascular death.

    Science.gov (United States)

    Cocho, D; Monell, J; Planells, G; Ricciardi, A C; Pons, J; Boltes, A; Espinosa, J; Ayats, M; Garcia, N; Otermin, P

    2016-01-01

    The 90-day risk of cerebral infarction in patients with transient ischaemic attack (TIA) is estimated at between 8% and 20%. There is little consensus as to which diagnostic strategy is most effective. This study evaluates the benefits of early transthoracic echocardiography (TTE) with carotid and transcranial Doppler ultrasound in patients with TIA. Prospective study of patients with TIA in an emergency department setting. Demographic data, vascular risk factors, and ABCD(2) score were analysed. TIA aetiology was classified according to TOAST criteria. All patients underwent early vascular studies (TIA, myocardial infarction (MI), or vascular death during the first year. We evaluated 92 patients enrolled over 24 months. Mean age was 68.3±13 years and 61% were male. The mean ABCD(2) score was 3 points (≥5 in 30%). The distribution of TIA subtypes was as follows: 12% large-artery atherosclerosis; 30% cardioembolism; 10% small-vessel occlusion; 40% undetermined cause; and 8% rare causes. Findings from the early TTE led to a change in treatment strategy in 6 patients (6.5%) who displayed normal physical examination and ECG findings. At one year of follow-up, 3 patients had experienced stroke (3.2%) and 1 patient experienced MI (1%); no vascular deaths were identified. In our TIA patients, early vascular study and detecting patients with silent cardiomyopathy may have contributed to the low rate of vascular disease recurrence. Copyright © 2014 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

  15. The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice

    DEFF Research Database (Denmark)

    Wintmo, P.; Johansen, S. H.; Hansen, P. B. L.

    2017-01-01

    Aim: The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. Methods: AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic...... minipumps for 4 weeks. Results: In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P ... increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes. Conclusion: AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse...

  16. Preliminary results on 3D channel modeling: From theory to standardization

    KAUST Repository

    Kammoun, Abla

    2014-06-01

    Three dimensional (3D) beamforming (also elevation beamforming) is now gaining interest among researchers in wireless communication. The reason can be attributed to its potential for enabling a variety of strategies such as sector or user specific elevation beamforming and cell-splitting. Since these techniques cannot be directly supported by current LTE releases, the 3GPP is now working on defining the required technical specifications. In particular, a large effort is currently being made to get accurate 3D channel models that support the elevation dimension. This step is necessary as it will evaluate the potential of 3D and full dimensional (FD) beamforming techniques to benefit from the richness of real channels. This work aims at presenting the on-going 3GPP study item \\'study on 3D-channel model for elevation beamforming and FD-MIMO studies for LTE\\' and positioning it with respect to previous standardization works. © 2014 IEEE.

  17. Preliminary results on 3D channel modeling: From theory to standardization

    KAUST Repository

    Kammoun, Abla; Khanfir, Hajer; Altman, Zwi; Debbah, Mé roú ane; Kamoun, Mohamed Amine

    2014-01-01

    Three dimensional (3D) beamforming (also elevation beamforming) is now gaining interest among researchers in wireless communication. The reason can be attributed to its potential for enabling a variety of strategies such as sector or user specific elevation beamforming and cell-splitting. Since these techniques cannot be directly supported by current LTE releases, the 3GPP is now working on defining the required technical specifications. In particular, a large effort is currently being made to get accurate 3D channel models that support the elevation dimension. This step is necessary as it will evaluate the potential of 3D and full dimensional (FD) beamforming techniques to benefit from the richness of real channels. This work aims at presenting the on-going 3GPP study item 'study on 3D-channel model for elevation beamforming and FD-MIMO studies for LTE' and positioning it with respect to previous standardization works. © 2014 IEEE.

  18. Mechanisms of vegetation-induced channel narrowing of an unregulated canyon river: Results from a natural field-scale experiment

    Science.gov (United States)

    Manners, Rebecca B.; Schmidt, John C.; Scott, Michael L.

    2014-04-01

    The lower Yampa River in Yampa Canyon, western Colorado serves as a natural, field-scale experiment, initiated when the invasive riparian plant, tamarisk (Tamarix spp.), colonized an unregulated river. In response to tamarisk's rapid invasion, the channel narrowed by 6% in the widest reaches since 1961. Taking advantage of this unique setting, we reconstructed the geomorphic and vegetation history in order to identify the key mechanisms for which, in the absence of other environmental perturbations, vegetation alters fluvial processes that result in a narrower channel. From our reconstruction, we identified a distinct similarity in the timing and magnitude of tamarisk encroachment and channel change, albeit with a lag in the channel response, thus suggesting tamarisk as the driving force. Within a decade of establishment, tamarisk effectively trapped sediment and, as a result, increased floodplain construction rates. Increasing tamarisk coverage over time also reduced the occurrence of floodplain stripping. Tamarisk recruitment was driven by both hydrologic and hydraulic variables, and the majority of tamarisk plants (84%) established below the stage of the 2-year flood. Thus, upon establishment nearly all plants regularly interact with the flow and sediment transport field. Our analyses were predicated on the hypothesis that the flow regime of the Yampa River was stationary, and that only the riparian vegetation community had changed. While not heavily impacted by water development, we determined that some aspects of the flow regime have shifted. However, this shift, which involved the clustering in time of extremely wet and dry years, did not influence fluvial processes directly. Instead these changes directly impacted riparian vegetation and changes in vegetation cover, in turn, altered fluvial processes. Today, the rate of channel change and new tamarisk recruitment is small. We believe that the rapid expansion of tamarisk and related floodplain construction

  19. Micro Vascular Plug (MVP)-assisted vessel occlusion in neurovascular pathologies: technical results and initial clinical experience.

    Science.gov (United States)

    Beaty, Narlin B; Jindal, Gaurav; Gandhi, Dheeraj

    2015-10-01

    Deconstructive approaches may be necessary to treat a variety of neurovascular pathologies. Recently, a new device has become available for endovascular arterial occlusion that may have unique applications in neurovascular disease. The Micro Vascular Plug (MVP, Reverse Medical, Irvine, California, USA) has been designed for vessel occlusion through targeted embolization. To report the results from our initial experience with eight consecutive patients in whom the MVP was used to achieve endovascular occlusion of an artery in the head and neck. Eight consecutive patients treated over a nine-month period were included. The patients' radiographic and electronic medical records were retrospectively reviewed. Specifically demographic information, clinical indication, site of arterial occlusion, size of MVP, time to vessel occlusion, clinical complications, use of other secondary embolic agents, and clinical outcome were recorded. Follow-up information when available is presented. The MVP was used in eight patients for the treatment of neurovascular disease. Indications for treatment included post-traumatic head/neck bleeding (n=3), carotid-cavernous fistula (1), vertebral-vertebral fistula (1), giant fusiform vertebral aneurysm (1), stump-emboli after carotid dissection (1), and iatrogenic vertebral artery penetrating injury (1). One device was used in five patients, two in two patients, and one patient with extensive vertebral-vertebral venous fistula required three plugs to effectively trap the fistula from proximal and distal aspects. Vessel occlusion was obtained in MVP in neurovascular disease. Use of this device may be associated with shorter procedural times and cost savings in comparison with the use of microcoils for vessel occlusion. Our experience shows that MVP can have unique applications in neurovascular pathologies and it complements other occlusive devices. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted

  20. Inactivation of the Sema5a gene results in embryonic lethality and defective remodeling of the cranial vascular system

    NARCIS (Netherlands)

    Fiore, Roberto; Rahim, Belquis; Christoffels, Vincent M.; Moorman, Antoon F. M.; Püschel, Andreas W.

    2005-01-01

    The semaphorins are a large family of proteins involved in the patterning of both the vascular and the nervous systems. In order to analyze the function of the membrane-bound semaphorin 5A (Sema5A), we generated mice homozygous for a null mutation in the Sema5a gene. Homozygous null mutants die

  1. Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Timothy L. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2005-12-01

    As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive interference suppression, and DBPSK, this method can communicate data as fast as 5 kbps. A third technique, dubbed the ''reflected-power'' configuration, communicates digital data by modulating a pulsed carrier by varying the acoustic impedance at the internal transducer-wall interface. The paradigms of the latter two configurations are believed to be unique. All modulation methods are based on the premise that the wall cannot be breached in any way and can therefore be viably implemented with power delivered wirelessly through the acoustic channel using ultrasound. Methods

  2. Amiloride blocks lithium entry through the sodium channel thereby attenuating the resultant nephrogenic diabetes insipidus.

    NARCIS (Netherlands)

    Kortenoeven, M.L.A.; Li, Y.; Shaw, S.M.; Gaeggeler, H.P.; Rossier, B.C.; Wetzels, J.F.M.; Deen, P.M.T.

    2009-01-01

    Lithium therapy frequently induces nephrogenic diabetes insipidus; amiloride appears to prevent its occurrence in some clinical cases. Amiloride blocks the epithelial sodium channel (ENaC) located in the apical membrane of principal cells; hence one possibility is that ENaC is the main entry site

  3. In vivo evidence for long-term vascular remodeling resulting from chronic cerebral hypoperfusion in mice

    OpenAIRE

    Struys, Tom; Govaerts, Kristof; Oosterlinck, Wouter; Casteels, Cindy; Bronckaers, Annelies; Koole, Michel; Van Laere, Koen; Herijgers, Paul; Lambrichts, Ivo; Himmelreich, Uwe; Dresselaers, Tom

    2016-01-01

    We have characterized both acute and long-term vascular and metabolic effects of unilateral common carotid artery occlusion in mice by in vivo magnetic resonance imaging and positron emission tomography. This common carotid artery occlusion model induces chronic cerebral hypoperfusion and is therefore relevant to both preclinical stroke studies, where it serves as a control condition for a commonly used mouse model of ischemic stroke, and neurodegeneration, as chronic hypoperfusion is causati...

  4. Some experimental results on flow in a diverging 2D channel

    Czech Academy of Sciences Publication Activity Database

    Antoš, Pavel; Hladík, Ondřej; Jonáš, Pavel; Uruba, Václav

    2013-01-01

    Roč. 13, č. 1 (2013), s. 297-298 ISSN 1617-7061. [Annual Meeting of the International Association of Applied Mathematics and Mechanics /84./. Novi Sad, 18.03.2013-22.03.2013] R&D Projects: GA ČR GAP101/12/1271 Institutional support: RVO:61388998 Keywords : free stream turbulence * negative pressure gradient * diverging 2D channel Subject RIV: BK - Fluid Dynamics http://onlinelibrary.wiley.com/doi/10.1002/pamm.201310144/pdf

  5. Initial Results of Image-Guided Percutaneous Ablation as Second-Line Treatment for Symptomatic Vascular Anomalies

    International Nuclear Information System (INIS)

    Thompson, Scott M.; Callstrom, Matthew R.; McKusick, Michael A.; Woodrum, David A.

    2015-01-01

    PurposeThe purpose of this study was to determine the feasibility, safety, and early effectiveness of percutaneous image-guided ablation as second-line treatment for symptomatic soft-tissue vascular anomalies (VA).Materials and MethodsAn IRB-approved retrospective review was undertaken of all patients who underwent percutaneous image-guided ablation as second-line therapy for treatment of symptomatic soft-tissue VA during the period from 1/1/2008 to 5/20/2014. US/CT- or MRI-guided and monitored cryoablation or MRI-guided and monitored laser ablation was performed. Clinical follow-up began at one-month post-ablation.ResultsEight patients with nine torso or lower extremity VA were treated with US/CT (N = 4) or MRI-guided (N = 2) cryoablation or MRI-guided laser ablation (N = 5) for moderate to severe pain (N = 7) or diffuse bleeding secondary to hemangioma–thrombocytopenia syndrome (N = 1). The median maximal diameter was 9.0 cm (6.5–11.1 cm) and 2.5 cm (2.3–5.3 cm) for VA undergoing cryoablation and laser ablation, respectively. Seven VA were ablated in one session, one VA initially treated with MRI-guided cryoablation for severe pain was re-treated with MRI-guided laser ablation due to persistent moderate pain, and one VA was treated in a planned two-stage session due to large VA size. At an average follow-up of 19.8 months (range 2–62 months), 7 of 7 patients with painful VA reported symptomatic pain relief. There was no recurrence of bleeding at five-year post-ablation in the patient with hemangioma–thrombocytopenia syndrome. There were two minor complications and no major complications.ConclusionImage-guided percutaneous ablation is a feasible, safe, and effective second-line treatment option for symptomatic VA

  6. Initial Results of Image-Guided Percutaneous Ablation as Second-Line Treatment for Symptomatic Vascular Anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Scott M., E-mail: Thompson.scott@mayo.edu [Mayo Clinic, Mayo Graduate School, Mayo Medical School and the Mayo Clinic Medical Scientist Training Program, College of Medicine (United States); Callstrom, Matthew R., E-mail: callstrom.matthew@mayo.edu; McKusick, Michael A., E-mail: mckusick.michael@mayo.edu; Woodrum, David A., E-mail: woodrum.david@mayo.edu [Mayo Clinic, Department of Radiology, College of Medicine (United States)

    2015-10-15

    PurposeThe purpose of this study was to determine the feasibility, safety, and early effectiveness of percutaneous image-guided ablation as second-line treatment for symptomatic soft-tissue vascular anomalies (VA).Materials and MethodsAn IRB-approved retrospective review was undertaken of all patients who underwent percutaneous image-guided ablation as second-line therapy for treatment of symptomatic soft-tissue VA during the period from 1/1/2008 to 5/20/2014. US/CT- or MRI-guided and monitored cryoablation or MRI-guided and monitored laser ablation was performed. Clinical follow-up began at one-month post-ablation.ResultsEight patients with nine torso or lower extremity VA were treated with US/CT (N = 4) or MRI-guided (N = 2) cryoablation or MRI-guided laser ablation (N = 5) for moderate to severe pain (N = 7) or diffuse bleeding secondary to hemangioma–thrombocytopenia syndrome (N = 1). The median maximal diameter was 9.0 cm (6.5–11.1 cm) and 2.5 cm (2.3–5.3 cm) for VA undergoing cryoablation and laser ablation, respectively. Seven VA were ablated in one session, one VA initially treated with MRI-guided cryoablation for severe pain was re-treated with MRI-guided laser ablation due to persistent moderate pain, and one VA was treated in a planned two-stage session due to large VA size. At an average follow-up of 19.8 months (range 2–62 months), 7 of 7 patients with painful VA reported symptomatic pain relief. There was no recurrence of bleeding at five-year post-ablation in the patient with hemangioma–thrombocytopenia syndrome. There were two minor complications and no major complications.ConclusionImage-guided percutaneous ablation is a feasible, safe, and effective second-line treatment option for symptomatic VA.

  7. Experimental Results and Issues on Equalization for Nonlinear Memory Channel: Pre-Cursor Enhanced Ram-DFE Canceler

    Science.gov (United States)

    Yuan, Lu; LeBlanc, James

    1998-01-01

    This thesis investigates the effects of the High Power Amplifier (HPA) and the filters over a satellite or telemetry channel. The Volterra series expression is presented for the nonlinear channel with memory, and the algorithm is based on the finite-state machine model. A RAM-based algorithm operating on the receiver side, Pre-cursor Enhanced RAM-FSE Canceler (PERC) is developed. A high order modulation scheme , 16-QAM is used for simulation, the results show that PERC provides an efficient and reliable method to transmit data on the bandlimited nonlinear channel. The contribution of PERC algorithm is that it includes both pre-cursors and post-cursors as the RAM address lines, and suggests a new way to make decision on the pre-addresses. Compared with the RAM-DFE structure that only includes post- addresses, the BER versus Eb/NO performance of PERC is substantially enhanced. Experiments are performed for PERC algorithms with different parameters on AWGN channels, and the results are compared and analyzed. The investigation of this thesis includes software simulation and hardware verification. Hardware is setup to collect actual TWT data. Simulation on both the software-generated data and the real-world data are performed. Practical limitations are considered for the hardware collected data. Simulation results verified the reliability of the PERC algorithm. This work was conducted at NMSU in the Center for Space Telemetering and Telecommunications Systems in the Klipsch School of Electrical and Computer Engineering Department.

  8. S100A4 and BMP-2 Co-Dependently Induce Vascular Smooth Muscle Cell Migration via pERK and Chloride Intracellular Channel 4 (CLIC4)

    Science.gov (United States)

    Spiekerkoetter, Edda; Guignabert, Christophe; de Jesus Perez, Vinicio; Alastalo, Tero-Pekka; Powers, Janine M; Wang, Lingli; Lawrie, Allan; Ambartsumian, Noona; Schmidt, Ann-Marie; Berryman, Mark; Ashley, Richard H; Rabinovitch, Marlene

    2009-01-01

    Rationale S100A4/Mts1 is implicated in motility of human pulmonary artery smooth muscle cells (hPASMC), through an interaction with the receptor for advanced glycation end products (RAGE). Objective We hypothesized that S100A4/Mts1-mediated hPASMC motility might be enhanced by loss of function of bone morphogenetic protein (BMP) receptor (R) II, observed in pulmonary arterial hypertension (PAH). Methods and Results Both S100A4/Mts1 (500ng/ml) and BMP-2 (10ng/ml) induce migration of hPASMCS in a novel co-dependent manner, in that the response to either ligand is lost with anti-RAGE or BMPRII siRNA. Phosphorylation of ERK is induced by both ligands and is required for motility by inducing MMP2 activity, but phosphoERK1/2 is blocked by anti-RAGE and not by BMPRII siRNA. In contrast, BMPRII siRNA, but not anti-RAGE, reduces expression of intracellular chloride channel 4 (CLIC4), a scaffolding molecule necessary for motility in response to S100A4/Mts1 or BMP-2. Reduced CLIC4 expression does not interfere with S100A4/Mts1 internalization or its interaction with myosin heavy chain IIA (MHCIIA), but does alter alignment of MHCIIA and actin filaments creating the appearance of vacuoles. This abnormality is associated with reduced peripheral distribution and/or delayed activation of RhoA and Rac1, small GTPases required for retraction and extension of lamellipodiae in motile cells. Conclusions Our studies demonstrate how a single ligand (BMP-2 or S100A4/Mts1) can recruit multiple cell surface receptors to relay signals that coordinate events culminating in a functional response, i.e., cell motility. We speculate that this carefully controlled process limits signals from multiple ligands, but could be subverted in disease. PMID:19713532

  9. Results of laboratory tests of the information-measurement system of the five-channel spectrophotometer

    International Nuclear Information System (INIS)

    Bukach, A.B.

    1979-01-01

    The study of technical characteristics of the five-channel spectrophotometer detecting star spectra in the 3125-8570 A range was carried out. The optimal conditions of photomultipliers and amplifiers allow to count statistically distributed pulses with the time resolution up to 50 ns. Detection, with printing and perforation, of the pulses rate has the absolute error of about +- 1 pulse, when the counting rate changes from 100 to 10 4 s -1 . The step-motor system and the scanning mechanism give the spectral line position with an accuracy of +- 0.2 step (+- 2 Mcm, i.e. 0.03 A for the first order of grating). Instrumental profile effect on the line position is investigated and the dispersion curves are obtained

  10. Seismarmara experiment: results from reprocessing of selected multi-channel seismic reflection profiles

    Science.gov (United States)

    Cetin, S.; Voogd, B.; Carton, H.; Laigle, M.; Becel, A.; Saatcilar, R.; Singh, S.; Hirn, A.

    2003-04-01

    The North Anatolian Fault (NAF) has been responsible for the earthquakes of Izmit and Duzce in 1999. The occurrence of these earthquakes has drawn scientific attention into the Sea of Marmara since the NAF enters into the Sea of Marmara where the latest Izmit earthquake rupture stopped. The SEISMARMARA-2001 survey is a combined seismic reflection, refraction and earthquake experiment carried out in 2001 in the Marmara Region in Turkey by French-Turkish scientific cooperation. The objectives of this survey were to image the various branches of the NAF and related other fault systems. R/V Le Nadir was equipped with a 4.5 km long streamer with 360 channels and a large airgun source. During Leg 1, a grid of large regional lines encompassing the whole Marmara trough was shot. For part of them a strong 8100 cu.in. source for deepest penetration was used, with a 150 m shot interval giving a 15-fold coverage. Another part was shot for a higher resolution with a 2900 cu. in. array at a 50m or 38 m interval to give a 45 or 60-fold coverage. The latter acquisition parameters were used for Leg 2 that was devoted to a very dense grid of lines in the Cinarcik Basin Reprocessing of the multi-channel seismic data is currently being undertaken in several Institutions using different seismic processing softwares (GeoVecteur, ProMAX, Focus), to take advantage of the diverse acquisitions and cope with their limitations, for instance high fold-order for Leg 2 and strength of signal but loose spatial sampling for the bigger source. The main objectives of the reprocessing of the selected profiles are to do a detailed velocity analysis and stacking after deconvolution, filtering to remove or suppress deep sea bottom multiples and out of plane reflections, and time-migration and depth conversion and thus reveal both the shallow and deeper reflection image of the crust in the Sea of Marmara. We show that choosing an appropriate processing sequence for different sources and acquisition

  11. Expanded Stem Cells, Stromal-Vascular Fraction, and Platelet-Rich Plasma Enriched Fat: Comparing Results of Different Facial Rejuvenation Approaches in a Clinical Trial.

    Science.gov (United States)

    Rigotti, Gino; Charles-de-Sá, Luiz; Gontijo-de-Amorim, Natale Ferreira; Takiya, Christina Maeda; Amable, Paola Romina; Borojevic, Radovan; Benati, Donatella; Bernardi, Paolo; Sbarbati, Andrea

    2016-03-01

    In a previous study, the authors demonstrated that treatment with expanded adipose-derived stem cells or stromal vascular fraction (SVF)-enriched fat modify the pattern of the dermis in human beings, representing a skin rejuvenation effect. Considering that expanded stem cells require a cell factor, the authors wanted to assess similar results by replacing them with platelet-rich plasma (PRP), which is easier to obtain and for which an empirical regenerative effect has been already described. To determine if PRP injection could replace the cutaneous regenerative effect of adipose-derived stem cells. This study was performed in 13 patients who were candidates for facelift. The patients underwent sampling of fat by liposuction from the abdomen and submitted to one of three protocols: injection of SVF-enriched fat or expanded adipose-derived stem cells or fat plus PRP in the preauricular areas. Fragments of skin were removed before and 3 months after treatment and analyzed by optical and electron microscopy. The use of fat plus PRP led to the presence of more pronounced inflammatory infiltrates and a greater vascular reactivity, increasing in vascular permeability and a certain reactivity of the nervous component. The addition of PRP did not improve the regenerative effect. The use of PRP did not have significant advantages in skin rejuvenation over the use of expanded adipose-derived stem cells or SVF-enriched fat. The effect of increased vascular reactivity may be useful in pathological situations in which an intense angiogenesis is desirable, such as tissular ischemia. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  12. Bone marrow mononuclear cell implantation in myocardial laser channels in the ischemic heart disease surgery. Long-term results

    Science.gov (United States)

    Chernyavskiy, Alexander; Fomichev, Alexey; Minin, Stanislav; Nikitin, Nikita

    2017-10-01

    Background: The problem of incomplete myocardial revascularization for diffuse and distal lesions of the myocardium is still relevant. We assessed the clinical and instrumental long-term results of autologous bone marrow cell (BMC) implantation in laser channels in ischemic heart disease with diffuse and distal coronary disease. 35 coronary heart disease (CHD) patients with diffuse and distal coronary disease during coronary artery bypass grafting (CABG) underwent BMC implantation in laser channels. The control group consisted of 29 patients. All patients in this group underwent only CABG. Clinical and instrumental assessment of the method's effect was carried out at two weeks, six months, and six years after surgery. Indirect revascularization showed more significant decreasing of the functional class (FC) New York Heart Association (NYHA), myocardial perfusion and contractility improvement. Autologous BMC implantation in laser channels is an effective method of CHD surgical treatment if it is impossible to perform direct myocardial revascularization. The indirect revascularization effect is formed in the first six months after surgery and remains at the same level for six years.

  13. Dose-reduced 16-slice multidetector-row spiral computed tomography in children with bronchoscopically suspected vascular tracheal stenosis - initial results

    International Nuclear Information System (INIS)

    Honnef, D.; Wildberger, J.E.; Das, M.; Hohl, C.; Mahnken, A.; Guenther, R.W.; Staatz, G.; Schnoering, H.; Vazquez-Jimenez, J.

    2006-01-01

    Purpose: To evaluate the diagnostic accuracy of contrast-enhanced dose-reduced 16-slice multidetector-row CT (MDCT) in newborns and infants with fiberoptic bronchoscopically suspected vascular-induced tracheal stenosis. Materials and Methods: 12 children (4 days to 3 years, 1.2-13.5 kg body weight) were examined using i.v. contrast-enhanced 16-slice MDCT (SOMATOM Sensation 16, Forchheim, Germany) without breath-hold and under sedation (11/12). All MDCTs were performed with a dose reduction. The beam collimation was 16 x 0.75 mm, except in the case of one child. MPRs along the tracheal axis in the x-, y- and z-directions and volume-rendering-reconstructions (VRTs) were calculated based on a secondary raw data set in addition to conventional axial slices. 2 radiologists used a three-point grade scale to evaluate the image quality, motion, and contrast media artifacts as well as the usefulness of the 2D- and 3D-reconstructions for determining the diagnosis. Statistical analysis was performed on the basis of a Kappa test. Results: In all cases the cause of the fiberoptic bronchoscopically suspected tracheal stenosis was revealed: compression due to the brachiocephalic trunk (n=7), double aortic arch (n=2), lusorian artery (n=1), vascular compression of the left main bronchus (n=2). In 3 patients further thoracic anomalies, such as tracheobronchial (n=2), and vascular (n=2) and vertebral (n=1) anomalies were found. The attenuation in the anomalous vessels was 307±140 HU. The image noise was 9.8±1.9 HU. The mean dose reduction was 82.7±3.2% compared to a standard adult thoracic CT. All examinations were rated as diagnostically good (median 1, range 1, k=1). 3D images did not show any stair artifacts (median 2, range 1-2, k=1). The image noise was minor to moderate and hardly any motion artifacts were seen (median 1, range 1-2, k=0.8). Contrast media artifacts were rated zero to minor (median 1.5, range 1-2, k=0.676). MPRs (median 1, range 1, k=1) and VRTs (median 1

  14. Endothelial Cell Migration and Vascular Endothelial Growth Factor Expression Are the Result of Loss of Breast Tissue Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Amy; Cuevas, Ileana; Kenny, Paraic A; Miyake, Hiroshi; Mace, Kimberley; Ghajar, Cyrus; Boudreau, Aaron; Bissell, Mina; Boudreau, Nancy

    2009-05-26

    Recruiting a new blood supply is a rate-limiting step in tumor progression. In a three-dimensional model of breast carcinogenesis, disorganized, proliferative transformed breast epithelial cells express significantly higher expression of angiogenic genes compared with their polarized, growth-arrested nonmalignant counterparts. Elevated vascular endothelial growth factor (VEGF) secretion by malignant cells enhanced recruitment of endothelial cells (EC) in heterotypic cocultures. Significantly, phenotypic reversion of malignant cells via reexpression of HoxD10, which is lost in malignant progression, significantly attenuated VEGF expression in a hypoxia-inducible factor 1{alpha}-independent fashion and reduced EC migration. This was due primarily to restoring polarity: forced proliferation of polarized, nonmalignant cells did not induce VEGF expression and EC recruitment, whereas disrupting the architecture of growth-arrested, reverted cells did. These data show that disrupting cytostructure activates the angiogenic switch even in the absence of proliferation and/or hypoxia and restoring organization of malignant clusters reduces VEGF expression and EC activation to levels found in quiescent nonmalignant epithelium. These data confirm the importance of tissue architecture and polarity in malignant progression.

  15. PDGF-induced migration of synthetic vascular smooth muscle cells through c-Src-activated L-type Ca2+ channels with full-length CaV1.2 C-terminus.

    Science.gov (United States)

    Guo, Xiaoguang; Kashihara, Toshihide; Nakada, Tsutomu; Aoyama, Toshifumi; Yamada, Mitsuhiko

    2018-06-01

    In atherosclerosis, vascular smooth muscle cells (VSMC) migrate from the media toward the intima of the arteries in response to cytokines, such as platelet-derived growth factor (PDGF). However, molecular mechanism underlying the PDGF-induced migration of VSMCs remains unclear. The migration of rat aorta-derived synthetic VSMCs, A7r5, in response to PDGF was potently inhibited by a Ca V 1.2 channel inhibitor, nifedipine, and a Src family tyrosine kinase (SFK)/Abl inhibitor, bosutinib, in a less-than-additive manner. PDGF significantly increased Ca V 1.2 channel currents without altering Ca V 1.2 protein expression levels in A7r5 cells. This reaction was inhibited by C-terminal Src kinase, a selective inhibitor of SFKs. In contractile VSMCs, the C-terminus of Ca V 1.2 is proteolytically cleaved into proximal and distal C-termini (PCT and DCT, respectively). Clipped DCT is noncovalently reassociated with PCT to autoinhibit the channel activity. Conversely, in synthetic A7r5 cells, full-length Ca V 1.2 (Ca V 1.2FL) is expressed much more abundantly than truncated Ca V 1.2. In a heterologous expression system, c-Src activated Ca V 1.2 channels composed of Ca V 1.2FL but not truncated Ca V 1.2 (Ca V 1.2Δ1763) or Ca V 1.2Δ1763 plus clipped DCT. Further, c-Src enhanced the coupling efficiency between the voltage-sensing domain and activation gate of Ca V 1.2FL channels by phosphorylating Tyr1709 and Tyr1758 in PCT. Compared with Ca V 1.2Δ1763, c-Src could more efficiently bind to and phosphorylate Ca V 1.2FL irrespective of the presence or absence of clipped DCT. Therefore, in atherosclerotic lesions, phenotypic switching of VSMCs may facilitate pro-migratory effects of PDGF on VSMCs by suppressing posttranslational Ca V 1.2 modifications.

  16. Channel Power in Multi-Channel Environments

    NARCIS (Netherlands)

    M.G. Dekimpe (Marnik); B. Skiera (Bernd)

    2004-01-01

    textabstractIn the literature, little attention has been paid to instances where companies add an Internet channel to their direct channel portfolio. However, actively managing multiple sales channels requires knowing the customers’ channel preferences and the resulting channel power. Two key

  17. Experimental results on one-pion neutral current reaction in all channels induced by antineutrinos at CERN PS

    CERN Document Server

    Erriquez, O; Bullock, F W; Cavalli, D; Engel, J P; Fogli-Muciaccia, M T; Gamba, D; Guyonnet, J L; Halsteinslid, A; Henderson, R C W; Huss, D; Jones, T W; Marzari-Chiesa, A; Myklebost, K; Natali, S; Nuzzo, S; Paty, M; Pullia, A; Riccati, L; Riester, J L; Rognebakke, A; Rollier, M; Romero, A

    1980-01-01

    Single pion production, in antineutrino-nucleon interactions via the neutral current, has been studied in the bubble chamber Gargamelle, filled with propane. Complete analysis of the secondaries, including pi /sup 0/'s, has allowed a detailed study of all channels. After background and nuclear corrections, results are obtained which can be interpreted in terms of isospin structure of the neutral weak current and of the Salam-Weinberg angle. Agreement is found with the currently accepted value of sin/sup 2/ theta /sub w/ and the data suggest an important contribution of I=/sup 3///sub 2/ final states. (11 refs).

  18. New Exact and Asymptotic Results of Dual-Branch MRC over Correlated Nakagami-m Fading Channels

    KAUST Repository

    Al-Quwaiee, Hessa

    2015-05-01

    We present in this paper a new performance analysis results of dual-branch maximal-ratio combining over correlated Nakagami-m fading channels with arbitrary fading parameter. In particular, we derive exact closed-form expressions of the outage probability, the average bit error rate, and the ergodic capacity in terms of the extended generalized bivariate Meijer G- function. Moreover, we also provide simple closed- form asymptotic expressions in the high signal-to- noise ratio regime of these three fundamental performance measures. © 2015 IEEE.

  19. New Exact and Asymptotic Results of Dual-Branch MRC over Correlated Nakagami-m Fading Channels

    KAUST Repository

    Al-Quwaiee, Hessa; Alouini, Mohamed-Slim

    2015-01-01

    We present in this paper a new performance analysis results of dual-branch maximal-ratio combining over correlated Nakagami-m fading channels with arbitrary fading parameter. In particular, we derive exact closed-form expressions of the outage probability, the average bit error rate, and the ergodic capacity in terms of the extended generalized bivariate Meijer G- function. Moreover, we also provide simple closed- form asymptotic expressions in the high signal-to- noise ratio regime of these three fundamental performance measures. © 2015 IEEE.

  20. Chronic exposure to KATP channel openers results in attenuated glucose sensing in hypothalamic GT1-7 neurons.

    Science.gov (United States)

    Haythorne, Elizabeth; Hamilton, D Lee; Findlay, John A; Beall, Craig; McCrimmon, Rory J; Ashford, Michael L J

    2016-12-01

    Individuals with Type 1 diabetes (T1D) are often exposed to recurrent episodes of hypoglycaemia. This reduces hormonal and behavioural responses that normally counteract low glucose in order to maintain glucose homeostasis, with altered responsiveness of glucose sensing hypothalamic neurons implicated. Although the molecular mechanisms are unknown, pharmacological studies implicate hypothalamic ATP-sensitive potassium channel (K ATP ) activity, with K ATP openers (KCOs) amplifying, through cell hyperpolarization, the response to hypoglycaemia. Although initial findings, using acute hypothalamic KCO delivery, in rats were promising, chronic exposure to the KCO NN414 worsened the responses to subsequent hypoglycaemic challenge. To investigate this further we used GT1-7 cells to explore how NN414 affected glucose-sensing behaviour, the metabolic response of cells to hypoglycaemia and K ATP activity. GT1-7 cells exposed to 3 or 24 h NN414 exhibited an attenuated hyperpolarization to subsequent hypoglycaemic challenge or NN414, which correlated with diminished K ATP activity. The reduced sensitivity to hypoglycaemia was apparent 24 h after NN414 removal, even though intrinsic K ATP activity recovered. The NN414-modified glucose responsiveness was not associated with adaptations in glucose uptake, metabolism or oxidation. K ATP inactivation by NN414 was prevented by the concurrent presence of tolbutamide, which maintains K ATP closure. Single channel recordings indicate that NN414 alters K ATP intrinsic gating inducing a stable closed or inactivated state. These data indicate that exposure of hypothalamic glucose sensing cells to chronic NN414 drives a sustained conformational change to K ATP , probably by binding to SUR1, that results in loss of channel sensitivity to intrinsic metabolic factors such as MgADP and small molecule agonists. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Channels Coordination Game Model Based on Result Fairness Preference and Reciprocal Fairness Preference: A Behavior Game Forecasting and Analysis Method

    Directory of Open Access Journals (Sweden)

    Chuan Ding

    2014-01-01

    preference and they are not jealous of manufacturers’ benefit, manufacturers will be more friendly to retailers. In such case, the total utility of the channel is higher compared with that of self-interest channel, and the utility of channel members is Pareto improved. If both manufactures and retailers consider reciprocal fairness preference, the manufacturers will give a lower wholesale price to the retailers. In return, the retailers will also reduce retail prices. Therefore, the total utility of the channels will not be less than the total utility of the channel coordination, as long as the reciprocity wholesale prices meet certain conditions.

  2. An Underlay Communication Channel for 5G Cognitive Mesh Networks: Packet Design, Implementation, Analysis, and Experimental Results

    Energy Technology Data Exchange (ETDEWEB)

    Tarek Haddadin; Stephen Andrew Laraway; Arslan Majid; Taylor Sibbett; Daryl Leon Wasden; Brandon F Lo; Lloyd Landon; David Couch; Hussein Moradi; Behrouz Farhang-Boroujeny

    2016-04-01

    This paper proposes and presents the design and implementation of an underlay communication channel (UCC) for 5G cognitive mesh networks. The UCC builds its waveform based on filter bank multicarrier spread spectrum (FB-MCSS) signaling. The use of this novel spread spectrum signaling allows the device-to-device (D2D) user equipments (UEs) to communicate at a level well below noise temperature and hence, minimize taxation on macro-cell/small-cell base stations and their UEs in 5G wireless systems. Moreover, the use of filter banks allows us to avoid those portions of the spectrum that are in use by macro-cell and small-cell users. Hence, both D2D-to-cellular and cellular-to-D2D interference will be very close to none. We propose a specific packet for UCC and develop algorithms for packet detection, timing acquisition and tracking, as well as channel estimation and equalization. We also present the detail of an implementation of the proposed transceiver on a software radio platform and compare our experimental results with those from a theoretical analysis of our packet detection algorithm.

  3. Chronic Prenatal Hypoxia Down-Regulated BK Channel Β1 Subunits in Mesenteric Artery Smooth Muscle Cells of the Offspring

    Directory of Open Access Journals (Sweden)

    Bailin Liu

    2018-02-01

    Full Text Available Background/Aims: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK channels in offspring mesenteric arteries following prenatal hypoxia. Methods: Pregnant rats were exposed to normoxic control (21% O2, Con or hypoxic (10.5% O2, Hy conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR. Results: Prenatal hypoxia increased pressor responses and vasoconstrictions to phenylephrine in the offspring. Whole-cell currents density of BK channels and amplitude of spontaneous transient outward currents (STOCs, not the frequency, were significantly reduced in Hy vascular myocytes. The sensitivity of BK channels to voltage, Ca2+, and tamoxifen were reduced in Hy myocytes, whereas the number of channels per patch and the single-channel conductance were unchanged. Prenatal hypoxia impaired NS1102- and tamoxifen-mediated relaxation in mesenteric arteries precontracted with phenylephrine in the presence of Nω-nitro-L-arginine methyl ester. The mRNA and protein expression of BK channel β1, not the α-subunit, was decreased in Hy mesenteric arteries. Conclusions: Impaired BK channel β1-subunits in vascular smooth muscle cells contributed to vascular dysfunction in the offspring exposed to prenatal hypoxia.

  4. Potassium channels as drugs targets in therapy of cardiovascular diseases: 25 years later

    Directory of Open Access Journals (Sweden)

    Protić Dragana

    2013-03-01

    Full Text Available Potassium channels are the most variable ion channel group. They participate in numerous cardiovascular functions, for example regulation of vascular tone, maintenance of resting cardiac membrane potential and excitability of cardiac conduction tissue. Both drugs and endogenous ligands could modulate potassium channel function, belonging to the potassium channel blockers or openers. Modulation of potassium channels could be a therapeutic or adverse drug action. Class III antiarrhythmic agents block the potassium channels, thereby prolonging repolarization phase of action potential with resulting prolongation of effective refractory period. Their effectiveness against supraventricular and ventricular arrhythmias should be weighted against their proarrhythmogenic potential. In addition, numerous other antiarrhythmic agents could modulate potassium channels as well. Diazoxide, minoxidil and nicorandil (well known arterial vasodilators, as well as numerous newly synthesized substances with still unknown therapeutic potential, belong to the potassium channel activators/openers. Therapeutic use of such vasodilators may involve treatment of hypertension (diazoxide, minoxidil and stable angina (nicorandil. Their use might be accompanied with side effects, such as vasodilation, edema, hypotension and reflex tachycardia. Potassium channel openers have also an important role in the treatment of peripheral vascular disease and pulmonary hypertension. In the future, drugs with selective effects on the vascular or cardiac potassium channels could be useful therapeutic agents.

  5. POTASSIUM CHANNELS AS DRUGS TARGETS IN THERAPY OF CARDIOVASCULAR DESEASES: 25 YEARS LATER

    Directory of Open Access Journals (Sweden)

    Protić Dragana

    2013-01-01

    Full Text Available Potassium channels are the most variable ion channel group. They participate in numerous cardiovascular functions, for example regulation of vascular tone, maintenance of resting cardiac membrane potential and excitability of cardiac conduction tissue. Both drugs and endogenous ligands could modulate potassium channel function, belonging to the potassium channel blockers or openers. Modulation of potassium channels could be a therapeutic or adverse drug action. Class III antiarrhythmic agents block the potassium channels, thereby prolonging repolarization phase of action potential with resulting prolongation of effective refractory period. Their effectiveness against supraventricular and ventricular arrhythmias should be weighted against their proarrhythmogenic potential. In addition, numerous other antiarrhythmic agents could modulate potassium channels as well. Diazoxide, minoxidil and nicorandil (well known arterial vasodilators, as well as numerous newly synthesized substances with still unknown therapeutic potential, belong to the potassium channel activators/ openers. Therapeutic use of such vasodilators may involve treatment of hypertension (diazoxide, minoxidil and stable angina (nicorandil. Their use might be accompanied with side effects, such as vasodilation, edema, hypotension and reflex tachycardia. Potassium channel openers have also an important role in the treatment of peripheral vascular disease and pulmonary hypertension. In the future, drugs with selective effects on the vascular or cardiac potassium channels could be useful therapeutic agents.

  6. Percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease using a transluminal endatherectomy catheter (TEC): Initial results and angiographic follow-up

    International Nuclear Information System (INIS)

    Rilinger, Norbert; Goerich, Johannes; Scharrer-Pamler, Reinhard; Vogel, Jochen; Tomczak, Reinhard; Merkle, Elmar; Sokiranski, Roman; Brambs, Hans-Juergen

    1997-01-01

    Purpose. To evaluate the clinical results of percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease. Methods. Rotational atherectomy was performed in 39 patients aged 39-87 years (mean 66.6 years). A total of 71 lesions (43 stenoses and 28 occlusions) were treated in 40 limbs. Additional balloon angioplasty was required in 54% of lesions. Fifteen patients (37.5%) presented in Fontaine stage II, 10 patients (25%) in Fontaine stage III and 15 patients (37.5%) in Fontaine stage IV. Rotational atherectomy at 750 rpm was carried out over a 0.014-inch guidewire with continuous aspiration into a vacuum, bottle. Follow-up angiography and color flow Doppler examinations were performed in 22 patients (23 limbs) after a mean period of 6 months (range 2-14 months). Results. There was one primary technical failure. In 36 of 40 lesions there was a good angiographic result with residual stenoses in less than 30%. In 70 lesions treated by rotational atherectomy, however, 54% showed residual stenoses of 30%-50% and these cases required additional balloon angioplasty. The mean ankle-brachial index improved significantly (p<0.001), from 0.49 before the procedure to 1.01 after the procedure. A single distal embolus, related to primary recanalization, occurred and there were two large inguinal hematomas. Cumulative clinical patency after 6 months was 83.8% and cumulative angiographic patency after 6 months was 79.1%. Conclusion. Percutaneous rotational atherectomy is a promising approach for the treatment of chronic peripheral vascular disease. Further prospective, randomized studies are necessary to compare percutaneous transluminal angioplasty with this new technical approach

  7. Indian television channels become vehicle for tobacco advertisement, promotion and sponsorship (TAPS violations in India - results of a sub-national survey in a northern Indian city

    Directory of Open Access Journals (Sweden)

    Ramesh Chand

    2018-03-01

    Full Text Available Background Indian tobacco control legislation (Section 5, subsequent rules dated October 2 nd , 2012 of COTPA, 2003 puts complete ban on Tobacco Advertisement Promotion and Sponsorships (TAPS, but industry is circumventing the law to carry the bussiness. Rules also mandate that, if there are tobacco use scenes in a movie or television program, a health spot, an audio visual disclaimer and health warning must be displayed during the telecast. However, there are gaps in the implementation. It is important for law enforcers to understand the nature and types of TAPS violations being carried out through television channel to better prepared for taking action. Methods Total 32 television channels telecasted between January-March 2017 in Shimla city in Northern India selected through stratified random sampling were observed during prime time (19:00 PM-22:00 PM for their compliance to the provisions of Indian cinema and television rules, 2012. The TV programs including serials and movies and the advertisements in between the programs were assessed as per the pre-tested checklist. Results Direct advertisements were not found in any of the channel. In near one fourth of television channels, TAPS was carried out as surrogate advertisements in the form of mouth freshners and paan masala and brand stretching/trademark diversification. Atleast one smoking scene was found in 9 television channels playing the movie, however, specified health spot, audio-video disclaimer and health warning could be observed in eight channels. News channels and regional channels had comparatively more surrogate advertisments and smoking violations as compared to other channels. Conclusions Cinema and television rules under Section 5 of COTPA are not strictly implemented in Indian television channels. TAPS are being carried out as surrogate advertisments, brand stretching and trademark diversification. Statuary requirements recommended under the rules for scenes showing tobacco

  8. VASCULAR SURGERY

    African Journals Online (AJOL)

    2016-06-02

    Jun 2, 2016 ... with the literature from South Africa over the last four decades, and reflects the high rate of interpersonal violence in the country.14,15 As expected, cervical ... via the intact circle of Willis in young patients is the most likely explanation for the lack of strokes. Five patients were referred to the Durban vascular ...

  9. Vascular Disorders

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Vascular Disorders Email to a friend * required fields ...

  10. Ion channeling

    International Nuclear Information System (INIS)

    Erramli, H.; Blondiaux, G.

    1994-01-01

    Channeling phenomenon was predicted, many years ago, by stark. The first channeling experiments were performed in 1963 by Davies and his coworkers. Parallely Robinson and Oen have investigated this process by simulating trajectories of ions in monocrystals. This technique has been combined with many methods like Rutherford Backscattering Spectrometry (R.B.S.), Particles Induced X-rays Emission (P.I.X.E) and online Nuclear Reaction (N.R.A.) to localize trace elements in the crystal or to determine crystalline quality. To use channeling for material characterization we need data about the stopping power of the incident particle in the channeled direction. The ratios of channeled to random stopping powers of silicon for irradiation in the direction have been investigated and compared to the available theoretical results. We describe few applications of ion channeling in the field of materials characterization. Special attention is given to ion channeling combined with Charged Particle Activation Analysis (C.P.A.A.) for studying the behaviour of oxygen atoms in Czochralski silicon lattices under the influence of internal gettering and in different gaseous atmospheres. Association between ion channeling and C.P.A.A was also utilised for studying the influence of the growing conditions on concentration and position of carbon atoms at trace levels in the MOVPE Ga sub (1-x) Al sub x lattice. 6 figs., 1 tab., 32 refs. (author)

  11. Initial Results of Accelerated Stress Testing on Single-Channel and Multichannel Drivers: Solid-State Lighting Technology Area

    Energy Technology Data Exchange (ETDEWEB)

    None

    2018-02-28

    This report is the first in a series of studies on accelerated stress testing (AST) of drivers used for SSL luminaires, such as downlights, troffers, and streetlights. A representative group of two-stage commercial driver products was exposed to an AST environment consisting of 75°C and 75% relative humidity (7575). These drivers were a mix of single-channel drivers (i.e., a single output current for one LED primary) and multichannel drivers (i.e., separate output currents for multiple LED primaries). This AST environment was chosen because previous testing on downlights with integrated drivers demonstrated that 38% of the sample population failed in less than 2,500 hours of testing using this method. In addition to AST test results, the performance of an SSL downlight product incorporating an integrated, multichannel driver during extended room temperature operational life (RTOL) testing is also reported. A battery of measurements was used to evaluate these products during accelerated testing, including full electrical characterization (i.e., power consumption, PF, total harmonic distortion [THD], and inrush current) and photometric characterization of external LED loads attached to the drivers (i.e., flicker performance and lumen maintenance).

  12. TPC2 polymorphisms associated with a hair pigmentation phenotype in humans result in gain of channel function by independent mechanisms.

    Science.gov (United States)

    Chao, Yu-Kai; Schludi, Verena; Chen, Cheng-Chang; Butz, Elisabeth; Nguyen, O N Phuong; Müller, Martin; Krüger, Jens; Kammerbauer, Claudia; Ben-Johny, Manu; Vollmar, Angelika M; Berking, Carola; Biel, Martin; Wahl-Schott, Christian A; Grimm, Christian

    2017-10-10

    Two-pore channels (TPCs) are endolysosomal cation channels. Two members exist in humans, TPC1 and TPC2. Functional roles associated with the ubiquitously expressed TPCs include VEGF-induced neoangiogenesis, LDL-cholesterol trafficking and degradation, physical endurance under fasting conditions, autophagy regulation, the acrosome reaction in sperm, cancer cell migration, and intracellular trafficking of pathogens such as Ebola virus or bacterial toxins (e.g., cholera toxin). In a genome-wide association study for variants associated with human pigmentation characteristics two coding variants of TPC2, rs35264875 (encoding M484L) and rs3829241 (encoding G734E), have been found to be associated with a shift from brown to blond hair color. In two recent follow-up studies a role for TPC2 in pigmentation has been further confirmed. However, these human polymorphic variants have not been functionally characterized until now. The development of endolysosomal patch-clamp techniques has made it possible to investigate directly ion channel activities and characteristics in isolated endolysosomal organelles. We applied this technique here to scrutinize channel characteristics of the polymorphic TPC2 variants in direct comparison with WT. We found that both polymorphisms lead to a gain of channel function by independent mechanisms. We next conducted a clinical study with more than 100 blond- and brown/black-haired individuals. We performed a genotype/phenotype analysis and subsequently isolated fibroblasts from WT and polymorphic variant carriers for endolysosomal patch-clamp experimentation to confirm key in vitro findings.

  13. Cytotoxicity of VEGF121/rGel on vascular endothelial cells resulting in inhibition of angiogenesis is mediated via VEGFR-2

    Directory of Open Access Journals (Sweden)

    Hittelman Walter N

    2011-08-01

    Full Text Available Abstract Background The fusion protein VEGF121/rGel composed of the growth factor VEGF121 and the plant toxin gelonin targets the tumor neovasculature and exerts impressive anti-vascular effects. We have previously shown that VEGF121/rGel is cytotoxic to endothelial cells overexpressing VEGFR-2 but not to endothelial cells overexpressing VEGFR-1. In this study, we examined the basis for the specific toxicity of this construct and assessed its intracellular effects in vitro and in vivo. Methods We investigated the binding, cytotoxicity and internalization profile of VEGF121/rGel on endothelial cells expressing VEGFR-1 or VEGFR-2, identified its effects on angiogenesis models in vitro and ex vivo, and explored its intracellular effects on a number of molecular pathways using microarray analysis. Results Incubation of PAE/VEGFR-2 and PAE/VEGFR-1 cells with 125I-VEGF121/rGel demonstrated binding specificity that was competed with unlabeled VEGF121/rGel but not with unlabeled gelonin. Assessment of the effect of VEGF121/rGel on blocking tube formation in vitro revealed a 100-fold difference in IC50 levels between PAE/VEGFR-2 (1 nM and PAE/VEGFR-1 (100 nM cells. VEGF121/rGel entered PAE/VEGFR-2 cells within one hour of treatment but was not detected in PAE/VEGFR-1 cells up to 24 hours after treatment. In vascularization studies using chicken chorioallantoic membranes, 1 nM VEGF121/rGel completely inhibited bFGF-stimulated neovascular growth. The cytotoxic effects of VEGF121/rGel were not apoptotic since treated cells were TUNEL-negative with no evidence of PARP cleavage or alteration in the protein levels of select apoptotic markers. Microarray analysis of VEGF121/rGel-treated HUVECs revealed the upregulation of a unique "fingerprint" profile of 22 genes that control cell adhesion, apoptosis, transcription regulation, chemotaxis, and inflammatory response. Conclusions Taken together, these data confirm the selectivity of VEGF121/rGel for VEGFR-2

  14. Long-Term Blocking of Calcium Channels in mdx Mice Results in Differential Effects on Heart and Skeletal Muscle

    DEFF Research Database (Denmark)

    Jørgensen, Louise Helskov; Blain, Alison; Greally, Elizabeth

    2011-01-01

    in older mice. However, streptomycin treatment did not show positive effects in diaphragm or heart muscle, and heart pathology was worsened. Thus, blocking calcium channels even before disease onset does not prevent dystrophy, making this an unlikely treatment for DMD. These findings highlight......The disease mechanisms underlying dystrophin-deficient muscular dystrophy are complex, involving not only muscle membrane fragility, but also dysregulated calcium homeostasis. Specifically, it has been proposed that calcium channels directly initiate a cascade of pathological events by allowing...... calcium ions to enter the cell. The objective of this study was to investigate the effect of chronically blocking calcium channels with the aminoglycoside antibiotic streptomycin from onset of disease in the mdx mouse model of Duchenne muscular dystrophy (DMD). Treatment in utero onwards delayed onset...

  15. Vascular ultrasound.

    Science.gov (United States)

    Pilcher, D B; Ricci, M A

    1998-04-01

    Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

  16. Overview of vascular disease

    International Nuclear Information System (INIS)

    Bisset, G.S. III

    1998-01-01

    Vascular disease in the pediatric population is a poorly understood process which is often underestimated in its incidence. The common beginnings of such ubiquitous diseases as atherosclerosis manifest themselves at a cellular level shortly after birth. Other common systemic disorders, including congestive heart failure and sepsis, are also intricately associated with dysfunctional vasculature. Progress in the understanding of normal and pathophysiologic processes within the vascular system begins with the 'control center' - the endothelial cell. The purpose of this review is to consolidate a body of knowledge on the processes that occur at the cellular level within the blood vessel wall, and to simplify the understanding of how imbalances in these physiologic parameters result in vascular disease. (orig.)

  17. Loss of insulin-induced activation of TRPM6 magnesium channels results in impaired glucose tolerance during pregnancy.

    NARCIS (Netherlands)

    Nair, A.V.; Hocher, B.; Verkaart, S.A.J.; Zeeland, F. van; Pfab, T.; Slowinski, T.; Chen, Y.P.; Schlingmann, K.P.; Schaller, A.; Gallati, S.; Bindels, R.J.M.; Konrad, M.; Hoenderop, J.G.J.

    2012-01-01

    Hypomagnesemia affects insulin resistance and is a risk factor for diabetes mellitus type 2 (DM2) and gestational diabetes mellitus (GDM). Two single nucleotide polymorphisms (SNPs) in the epithelial magnesium channel TRPM6 (V(1393)I, K(1584)E) were predicted to confer susceptibility for DM2. Here,

  18. Man-made secondary channels along the river Rhine (The Netherlands); results of post-project monitoring

    NARCIS (Netherlands)

    Simons, J.H.E.J.; Bakker, C.; Schropp, M.H.I.; Jans, L.H.; Kok, F.R.; Grift, R.E.

    2001-01-01

    Owing to river regulation in the past and intensive farming, the ecological value of the floodplains of the River Rhine in The Netherlands has decreased dramatically. One way to restore riverine biotopes is to create permanently flowing channels in the floodplain. Along the River Waal, the main

  19. Synergistic activation of vascular TRPC6 channel by receptor and mechanical stimulation via phospholipase C/diacylglycerol and phospholipase A2/¿-hydroxylase/20-HETE pathways

    DEFF Research Database (Denmark)

    Inoue, Ryuji; Jensen, Lars Jørn; Jian, Zhong

    2009-01-01

    ). Single TRPC6 channel activity evoked by carbachol was also enhanced by a negative pressure added in the patch pipette. Mechanical potentiation of carbachol- or OAG-induced I(TRPC6) was abolished by small interfering RNA knockdown of cytosolic phospholipase A(2) or pharmacological inhibition of omega...... or Arg8 vasopressin was greatly enhanced by mechanical stimuli via 20-HETE production. Furthermore, myogenic response of pressurized mesenteric artery was significantly enhanced by weak receptor stimulation dependently on 20-HETE production. These results collectively suggest that simultaneous operation...

  20. Effects of ethanol on voltage-sensitive Na-channels in cultured skeletal muscle: Up-regulation as a result of chronic treatment

    International Nuclear Information System (INIS)

    Brodie, C.; Sampson, S.R.

    1990-01-01

    The effects of acute and chronic treatment with ethanol were studied on the number and activity of tetrodotoxin-sensitive Na-channels in cultured rat skeletal muscle. The number of channels was determined by measurements of specific binding of [3H] saxitoxin (STX) in whole cell preparations. Measurements were also made of the frequency and rate of rise of spontaneously occurring action potentials, which are the physiologic expression of Na-channel density. Acute ethanol (37.5-150 mM), while causing depolarization of membrane potential and blockade of electrical activity, was without effect on specific STX binding. Neither methanol, acetaldehyde nor ethylene glycol had significant effects on these properties when given acutely in the same concentrations as ethanol. Chronic ethanol caused dose-related increases in STX binding and action potential properties with maximal levels being attained after 3 days of treatment at a concentration of 150 mM. On removal of ethanol from the culture medium all properties returned to control levels after 48 hr. Both increased external K+ and tetrodotoxin, which up-regulate Na-channels by reducing cytosolic Ca++, potentiated the ethanol-induced increase in Na-channel density. The increase in STX binding was not associated with changes in affinity of the binding sites for the ligand but was completely prevented by treatment with cycloheximide and actinomycin D. The results demonstrate that ethanol interacts with the cell membrane to induce synthesis of STX-binding sites

  1. A study of various types of electronics for drift chambers: development of a test bench and results for 1500 channels

    International Nuclear Information System (INIS)

    Kostarakis, Panayotis.

    1976-01-01

    An electronic chain to be connected with drift chambers is studied for use in High Energy Physics. Studies have been made to define the best components to be put into the elements (amplifiers, cables, TDC...). Measurements have been done to determine the characteristics of the chosen elements. A test apparatus has been built to control each channel (about 1550). Finally all chain elements have been tested [fr

  2. Intermittent injections of osteocalcin reverse autophagic dysfunction and endoplasmic reticulum stress resulting from diet-induced obesity in the vascular tissue via the NFκB-p65-dependent mechanism.

    Science.gov (United States)

    Zhou, Bo; Li, Huixia; Liu, Jiali; Xu, Lin; Zang, Weijin; Wu, Shufang; Sun, Hongzhi

    2013-06-15

    The osteoblast-specific secreted molecule osteocalcin behaves as a hormone-regulating glucose and lipid metabolism, but the role of osteocalcin in cardiovascular disease (CVD) is not fully understood. In the present study, we investigated the effect of osteocalcin on autophagy and endoplasmic reticulum (ER) stress secondary to diet-induced obesity in the vascular tissue of mice and in vascular cell models and clarified the intracellular events responsible for osteocalcin-mediated effects. The evidences showed that intermittent injections of osteocalcin in mice fed the high-fat diet were associated with a reduced body weight gain, decreased blood glucose and improved insulin sensitivity compared with mice fed the high-fat diet receiving vehicle. Simultaneously, the administration of osteocalcin not only attenuated autophagy and ER stress but also rescued impaired insulin signaling in vascular tissues of mice fed a high-fat diet. Consistent with these results in vivo, the addition of osteocalcin reversed autophagy and ER stress and restored defective insulin sensitivity in vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) in the presence of tunicamycin or in knockout XBP-1 (a transcription factor which mediates ER stress response) cells or in Atg7(-/-) cells. The protective effects of osteocalcin were nullified by suppression of Akt, mammalian target of rapamycin (mTOR) or nuclear factor kappa B (NFκB), suggesting that osteocalcin inhibits autophagy, ER stress and improves insulin signaling in the vascular tissue and cells under insulin resistance in a NFκB-dependent manner, which may be a promising therapeutic strategies of cardiovascular dysfunction secondary to obesity.

  3. First results from car-to-car and car-to-infrastructure radio channel measurements at 5.2GHZ

    OpenAIRE

    Paier, Alexander; Kåredal, Johan; Czink, Nicolai; Hofstetter, Helmut; Dumard, Charlotte; Zemen, Thomas; Tufvesson, Fredrik; Mecklenbräuker, Christoph; Molisch, Andreas

    2007-01-01

    Car-to-car and car-to-infrastructure (henceforth called C2X) communications are constantly gaining importance for road-safety and other applications. In order to design efficient C2X systems, an understanding of realistic C2X propagation channels is required, but currently, only few measurements have been published. This paper presents a description of an extensive measurement campaign recently conducted in an urban scenario, a rural scenario, and on a highway. We focused on 4 ÿ 4 multiple-in...

  4. Renal posttransplant's vascular complications

    Directory of Open Access Journals (Sweden)

    Bašić Dragoslav

    2003-01-01

    Full Text Available INTRODUCTION Despite high graft and recipient survival figures worldwide today, a variety of technical complications can threaten the transplant in the postoperative period. Vascular complications are commonly related to technical problems in establishing vascular continuity or to damage that occurs during donor nephrectomy or preservation [13]. AIM The aim of the presenting study is to evaluate counts and rates of vascular complications after renal transplantation and to compare the outcome by donor type. MATERIAL AND METHODS A total of 463 kidneys (319 from living related donor LD and 144 from cadaveric donor - CD were transplanted during the period between June 1975 and December 1998 at the Urology & Nephrology Institute of Clinical Centre of Serbia in Belgrade. Average recipients' age was 33.7 years (15-54 in LD group and 39.8 (19-62 in CD group. Retrospectively, we analyzed medical records of all recipients. Statistical analysis is estimated using Hi-squared test and Fischer's test of exact probability. RESULTS Major vascular complications including vascular anastomosis thrombosis, internal iliac artery stenosis, internal iliac artery rupture obliterant vasculitis and external iliac vein rupture were analyzed. In 25 recipients (5.4% some of major vascular complications were detected. Among these cases, 22 of them were from CD group vs. three from LD group. Relative rate of these complications was higher in CD group vs. LD group (p<0.0001. Among these complications dominant one was vascular anastomosis thrombosis which occurred in 18 recipients (17 from CD vs. one from LD. Of these recipients 16 from CD lost the graft, while the rest of two (one from each group had lethal outcome. DISCUSSION Thrombosis of renal allograft vascular anastomosis site is the most severe complication following renal transplantation. In the literature, renal allograft thrombosis is reported with different incidence rates, from 0.5-4% [14, 15, 16]. Data from the

  5. Evaluation of femoral head vascularization in slipped capital femoral epiphysis before and after cannulated screw fixation with use of contrast-enhanced MRI: initial results

    International Nuclear Information System (INIS)

    Staatz, G.; Honnef, D.; Hohl, C.; Schmidt, T.; Guenther, R.W.; Kochs, A.; Roehrig, H.

    2007-01-01

    In this study we used contrast-enhanced magnetic resonance imaging (MRI) to evaluate the vascularization of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after cannulated screw fixation. Eleven consecutive children with SCFE, seven boys and four girls, aged 10-15 years were included in the study. There were no preslips; four children had acute, three acute-on-chronic, and four chronic SCFE. The MRI examinations were performed in a 1.5 Tesla MR scanner with use of a coronal STIR sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence, and a sagittal three-dimensional gradient-echo sequence. Morphology, signal intensities, and contrast-enhancement of the femoral head were assessed by two radiologists in consensus. Morphologic distortion of the physis, bone marrow edema within the metaphysis and epiphysis, and joint effusion were the preoperative MRI findings of SCFE in each child. In nine children, the vascularization of the femoral head before and after surgery was normal. In one child, a preoperative avascular zone in the superolateral aspect of the epiphysis revascularized completely after surgery. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction of the slip. We conclude that MRI allows for accurate evaluation of the femoral head vascularization before and after surgery in children with SCFE. (orig.)

  6. Evaluation of femoral head vascularization in slipped capital femoral epiphysis before and after cannulated screw fixation with use of contrast-enhanced MRI: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Staatz, G. [Friedrich-Alexander-University Erlangen-Nuernberg, Department of Radiology, Division of Pediatric Radiology, Erlangen (Germany); University Hospital of the RWTH Aachen, Department of Diagnostic Radiology, Aachen (Germany); Honnef, D.; Hohl, C.; Schmidt, T.; Guenther, R.W. [University Hospital of the RWTH Aachen, Department of Diagnostic Radiology, Aachen (Germany); Kochs, A.; Roehrig, H. [University Hospital of the RWTH Aachen, Department of Orthopaedic Surgery, Aachen (Germany)

    2007-01-15

    In this study we used contrast-enhanced magnetic resonance imaging (MRI) to evaluate the vascularization of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after cannulated screw fixation. Eleven consecutive children with SCFE, seven boys and four girls, aged 10-15 years were included in the study. There were no preslips; four children had acute, three acute-on-chronic, and four chronic SCFE. The MRI examinations were performed in a 1.5 Tesla MR scanner with use of a coronal STIR sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence, and a sagittal three-dimensional gradient-echo sequence. Morphology, signal intensities, and contrast-enhancement of the femoral head were assessed by two radiologists in consensus. Morphologic distortion of the physis, bone marrow edema within the metaphysis and epiphysis, and joint effusion were the preoperative MRI findings of SCFE in each child. In nine children, the vascularization of the femoral head before and after surgery was normal. In one child, a preoperative avascular zone in the superolateral aspect of the epiphysis revascularized completely after surgery. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction of the slip. We conclude that MRI allows for accurate evaluation of the femoral head vascularization before and after surgery in children with SCFE. (orig.)

  7. Bioresorbable Everolimus-Eluting Vascular Scaffold for Patients With Peripheral Artery Disease (ESPRIT I): 2-Year Clinical and Imaging Results.

    Science.gov (United States)

    Lammer, Johannes; Bosiers, Marc; Deloose, Koen; Schmidt, Andrej; Zeller, Thomas; Wolf, Florian; Lansink, Wouter; Sauguet, Antoine; Vermassen, Frank; Lauwers, Geert; Scheinert, Dierk; Popma, Jeffrey J; McGreevy, Robert; Rapoza, Richard; Schwartz, Lewis B; Jaff, Michael R

    2016-06-13

    This is the first-in-human study of a drug-eluting bioresorbable vascular scaffold (BVS) for treatment of peripheral artery disease (PAD) involving the external iliac artery (EIA) and superficial femoral artery (SFA). Drug-eluting BVS has shown promise in coronary arteries. The ESPRIT BVS system is a device-drug combination consisting of an everolimus-eluting poly-l-lactide scaffold. Safety and performance were evaluated in 35 subjects with symptomatic claudication. Lesions were located in the SFA (88.6%) and EIA (11.4%). Mean lesion length was 35.7 ± 16.0 mm. The study device was successfully deployed in 100% of cases, without recoil. Procedure-related minor complications were observed in 3 patients (groin hematoma, dissection). Within 2 years there was 1 unrelated death, but no patients in this cohort had an amputation. At 1 and 2 years, the binary restenosis rates were 12.1% and 16.1%, respectively, and target lesion revascularization was performed in 3 of 34 patients (8.8%) and 4 of 32 patients (11.8%), respectively. The ankle brachial index 0.75 ± 0.14 improved from pre-procedure to 0.96 ± 0.16 at 2 years' follow-up. At 2 years, 71.0% of the patients were Rutherford-Becker 0, and 93.5% achieved a maximum walking distance of 1,500 feet. The safety of the ESPRIT BVS was demonstrated with no procedure or device-related deaths or amputations within 2 years. The low occurrence of revascularizations was consistent with duplex-ultrasonography showing sustained patency at 2-years. (A Clinical Evaluation of the Abbott Vascular ESPRIT BVS [Bioresorbable Vascular Scaffold] System [ESPRIT I]; NCT01468974). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  8. Diabetes and Retinal Vascular Dysfunction

    Directory of Open Access Journals (Sweden)

    Eui Seok Shin

    2014-01-01

    Full Text Available Diabetes predominantly affects the microvascular circulation of the retina resulting in a range of structural changes unique to this tissue. These changes ultimately lead to altered permeability, hyperproliferation of endothelial cells and edema, and abnormal vascularization of the retina with resulting loss of vision. Enhanced production of inflammatory mediators and oxidative stress are primary insults with significant contribution to the pathogenesis of diabetic retinopathy (DR. We have determined the identity of the retinal vascular cells affected by hyperglycemia, and have delineated the cell autonomous impact of high glucose on function of these cells. We discuss some of the high glucose specific changes in retinal vascular cells and their contribution to retinal vascular dysfunction. This knowledge provides novel insight into the molecular and cellular defects contributing to the development and progression of diabetic retinopathy, and will aid in the development of innovative, as well as target specific therapeutic approaches for prevention and treatment of DR.

  9. Loss of insulin-induced activation of TRPM6 magnesium channels results in impaired glucose tolerance during pregnancy

    Science.gov (United States)

    Nair, Anil V.; Hocher, Berthold; Verkaart, Sjoerd; van Zeeland, Femke; Pfab, Thiemo; Slowinski, Torsten; Chen, You-Peng; Schlingmann, Karl Peter; Schaller, André; Gallati, Sabina; Bindels, René J.; Konrad, Martin; Hoenderop, Joost G.

    2012-01-01

    Hypomagnesemia affects insulin resistance and is a risk factor for diabetes mellitus type 2 (DM2) and gestational diabetes mellitus (GDM). Two single nucleotide polymorphisms (SNPs) in the epithelial magnesium channel TRPM6 (V1393I, K1584E) were predicted to confer susceptibility for DM2. Here, we show using patch clamp analysis and total internal reflection fluorescence microscopy, that insulin stimulates TRPM6 activity via a phosphoinositide 3-kinase and Rac1-mediated elevation of cell surface expression of TRPM6. Interestingly, insulin failed to activate the genetic variants TRPM6(V1393I) and TRPM6(K1584E), which is likely due to the inability of the insulin signaling pathway to phosphorylate TRPM6(T1391) and TRPM6(S1583). Moreover, by measuring total glycosylated hemoglobin (TGH) in 997 pregnant women as a measure of glucose control, we demonstrate that TRPM6(V1393I) and TRPM6(K1584E) are associated with higher TGH and confer a higher likelihood of developing GDM. The impaired response of TRPM6(V1393I) and TRPM6(K1584E) to insulin represents a unique molecular pathway leading to GDM where the defect is located in TRPM6. PMID:22733750

  10. The impact of level of education on vascular events and mortality in patients with type 2 diabetes mellitus: Results from the ADVANCE study.

    Science.gov (United States)

    Blomster, J I; Zoungas, S; Woodward, M; Neal, B; Harrap, S; Poulter, N; Marre, M; Williams, B; Chalmers, J; Hillis, G S

    2017-05-01

    The relationship between educational level and the risk of all-cause mortality is well established, whereas the association with vascular events in individuals with type 2 diabetes is not well described. Any association may reflect a link with common cardiovascular or lifestyle-based risk factors. The relationships between the highest level of educational attainment and major cardiovascular events, microvascular complications and all-cause mortality were explored in a cohort of 11,140 individuals with type 2 diabetes. Completion of formal education before the age of 16 was categorized as a low level of education. Regional differences between Asia, East Europe and Established Market Economies were also assessed. During a median of 5years of follow up, 1031 (9%) patients died, 1147 (10%) experienced a major cardiovascular event and 1136 (10%) a microvascular event. After adjustment for baseline characteristics and risk factors, individuals with lower education had an increased risk of cardiovascular events (hazard ratio (HR) 1.31, 95% CI 1.16-1.48, peducation was weakest in Established Market Economies and strongest in East Europe. A low level of education is associated with an increased risk of vascular events and death in patients with type 2 diabetes, independently of common lifestyle associated cardiovascular risk factors. The effect size varies between geographical regions. Copyright © 2017. Published by Elsevier B.V.

  11. 3D bioprinting for vascularized tissue fabrication

    Science.gov (United States)

    Richards, Dylan; Jia, Jia; Yost, Michael; Markwald, Roger; Mei, Ying

    2016-01-01

    3D bioprinting holds remarkable promise for rapid fabrication of 3D tissue engineering constructs. Given its scalability, reproducibility, and precise multi-dimensional control that traditional fabrication methods do not provide, 3D bioprinting provides a powerful means to address one of the major challenges in tissue engineering: vascularization. Moderate success of current tissue engineering strategies have been attributed to the current inability to fabricate thick tissue engineering constructs that contain endogenous, engineered vasculature or nutrient channels that can integrate with the host tissue. Successful fabrication of a vascularized tissue construct requires synergy between high throughput, high-resolution bioprinting of larger perfusable channels and instructive bioink that promotes angiogenic sprouting and neovascularization. This review aims to cover the recent progress in the field of 3D bioprinting of vascularized tissues. It will cover the methods of bioprinting vascularized constructs, bioink for vascularization, and perspectives on recent innovations in 3D printing and biomaterials for the next generation of 3D bioprinting for vascularized tissue fabrication. PMID:27230253

  12. Bioprinting for vascular and vascularized tissue biofabrication.

    Science.gov (United States)

    Datta, Pallab; Ayan, Bugra; Ozbolat, Ibrahim T

    2017-03-15

    Bioprinting is a promising technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision. Bioprinting enables the deposition of various biologics including growth factors, cells, genes, neo-tissues and extra-cellular matrix-like hydrogels. Benefits of bioprinting have started to make a mark in the fields of tissue engineering, regenerative medicine and pharmaceutics. Specifically, in the field of tissue engineering, the creation of vascularized tissue constructs has remained a principal challenge till date. However, given the myriad advantages over other biofabrication methods, it becomes organic to expect that bioprinting can provide a viable solution for the vascularization problem, and facilitate the clinical translation of tissue engineered constructs. This article provides a comprehensive account of bioprinting of vascular and vascularized tissue constructs. The review is structured as introducing the scope of bioprinting in tissue engineering applications, key vascular anatomical features and then a thorough coverage of 3D bioprinting using extrusion-, droplet- and laser-based bioprinting for fabrication of vascular tissue constructs. The review then provides the reader with the use of bioprinting for obtaining thick vascularized tissues using sacrificial bioink materials. Current challenges are discussed, a comparative evaluation of different bioprinting modalities is presented and future prospects are provided to the reader. Biofabrication of living tissues and organs at the clinically-relevant volumes vitally depends on the integration of vascular network. Despite the great progress in traditional biofabrication approaches, building perfusable hierarchical vascular network is a major challenge. Bioprinting is an emerging technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision

  13. Field Trial Results of a 14-channel GPR Integrated with a U.S. Program for 3-D Utility Mapping

    Science.gov (United States)

    Anspach, James H.

    2013-04-01

    Existing underground utilities continue to be a leading cause of highway construction delay claims in the United States. Although 80-90% of existing utilities can typically be discovered and mapped using a wide range of geophysical tools, there is a recognizable need to improve the process. Existing shortcomings to the utility mapping process include a lack of viable depth attributes, long field occupation times, low experience level of the field technicians, and separate survey / geophysics functions. The U.S. National Academies and its Transportation Research Board recently concluded a project on alleviating the existing utility mapping shortcomings through the development of enhanced GPR. An existing commercial 400MHz 14-channel towed array was enhanced with positioning and interpretation hardware and software over a 3-year US 2M program. Field trials for effectiveness were conducted in a city suburb commercialized environment where the relative permittivity values averaged 9.4. The effectiveness of enhanced GPR was compared to traditional utility mapping techniques (Single Channel GPR, FDEM, Acoustic, Sondes, Gradiometric Magnetometers) during the project. The project area utilities included natural gas, water, electric, telephone, cable, storm, sanitary, traffic control, and several unknown function lines. Depths for these utilities were mostly unknown. 81% of known (from records and field appurtenance visual observation) utilities were detected via traditional geophysical means. These traditional geophysical means also detected 14% additional and previously "unknown" utilities. The enhanced GPR detected approximately 40% of the known and unknown utilities, and found an additional 6% of utilities that were previously undetected. These additional utilities were subsequently determined to be small diameter abandoned water and gas systems in very poor and broken condition. Although it did well with metallic water and gas lines, communication and electric

  14. MRI of the wrist at 7 tesla using an eight-channel array coil combined with parallel imaging: preliminary results.

    Science.gov (United States)

    Chang, Gregory; Friedrich, Klaus M; Wang, Ligong; Vieira, Renata L R; Schweitzer, Mark E; Recht, Michael P; Wiggins, Graham C; Regatte, Ravinder R

    2010-03-01

    To determine the feasibility of performing MRI of the wrist at 7 Tesla (T) with parallel imaging and to evaluate how acceleration factors (AF) affect signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image quality. This study had institutional review board approval. A four-transmit eight-receive channel array coil was constructed in-house. Nine healthy subjects were scanned on a 7T whole-body MR scanner. Coronal and axial images of cartilage and trabecular bone micro-architecture (3D-Fast Low Angle Shot (FLASH) with and without fat suppression, repetition time/echo time = 20 ms/4.5 ms, flip angle = 10 degrees , 0.169-0.195 x 0.169-0.195 mm, 0.5-1 mm slice thickness) were obtained with AF 1, 2, 3, 4. T1-weighted fast spin-echo (FSE), proton density-weighted FSE, and multiple-echo data image combination (MEDIC) sequences were also performed. SNR and CNR were measured. Three musculoskeletal radiologists rated image quality. Linear correlation analysis and paired t-tests were performed. At higher AF, SNR and CNR decreased linearly for cartilage, muscle, and trabecular bone (r < -0.98). At AF 4, reductions in SNR/CNR were:52%/60% (cartilage), 72%/63% (muscle), 45%/50% (trabecular bone). Radiologists scored images with AF 1 and 2 as near-excellent, AF 3 as good-to-excellent (P = 0.075), and AF 4 as average-to-good (P = 0.11). It is feasible to perform high resolution 7T MRI of the wrist with parallel imaging. SNR and CNR decrease with higher AF, but image quality remains above-average.

  15. Vascularization of liver tumors - preliminary results with Coded Harmonic Angio (CHA), phase inversion imaging, 3D power Doppler and contrast medium-enhanced B-flow with second generation contrast agent (Optison).

    Science.gov (United States)

    Jung, E M; Kubale, R; Jungius, K-P; Jung, W; Lenhart, M; Clevert, D-A

    2006-01-01

    To investigate the dynamic value of contrast medium-enhanced ultrasonography with Optison for appraisal of the vascularization of hepatic tumors using harmonic imaging, 3D-/power Doppler and B-flow. 60 patients with a mean age of 56 years (range 35-76 years) with 93 liver tumors, including histopathologically proven hepatocellular carcinoma (HCC) [15 cases with 20 lesions], liver metastases of colorectal tumors [17 cases with 33 lesions], metastases of breast cancer [10 cases with 21 lesions] and hemangiomas [10 cases with 19 lesions] were prospectively investigated by means of multislice CT as well as native and contrast medium-enhanced ultrasound using a multifrequency transducer (2.5-4 MHz, Logig 9, GE). B scan was performed with additional color and power Doppler, followed by a bolus injection of 0.5 ml Optison. Tumor vascularization was evaluated with coded harmonic angio (CHA), pulse inversion imaging with power Doppler, 3D power Doppler and in the late phase (>5 min) with B-flow. In 15 cases with HCC, i.a. DSA was performed in addition. The results were also correlated with MRT and histological findings. Compared to spiral-CT/MRT, only 72/93 (77%) of the lesions could be detected in the B scan, 75/93 (81%) with CHA and 93/93 (100%) in the pulse inversion mode. Tumor vascularization was detectable in 43/93 (46%) of lesions with native power Doppler, in 75/93 (81%) of lesions after administering contrast medium in the CHA mode, in 81/93 (87%) of lesions in the pulse inversion mode with power Doppler and in 77/93 (83%) of lesions with contrast-enhanced B-flow. Early arterial and capillary perfusion was best detected with CHA, particularly in 20/20 (100%) of the HCC lesions, allowing a 3D reconstruction. 3D power Doppler was especially useful in investigating the tumor margins. Up to 20 min after contrast medium injection, B-flow was capable of detecting increased metastatic tumor vascularization in 42/54 (78%) of cases and intratumoral perfusion in 17/20 (85

  16. Lung irradiation induces pulmonary vascular remodelling resembling pulmonary arterial hypertension

    NARCIS (Netherlands)

    Ghobadi, G.; Bartelds, B.; van der Veen, S. J.; Dickinson, M. G.; Brandenburg, S.; Berger, R. M. F.; Langendijk, J. A.; Coppes, R. P.; van Luijk, P.

    Background Pulmonary arterial hypertension (PAH) is a commonly fatal pulmonary vascular disease that is often diagnosed late and is characterised by a progressive rise in pulmonary vascular resistance resulting from typical vascular remodelling. Recent data suggest that vascular damage plays an

  17. Eight channel fast scalar

    Energy Technology Data Exchange (ETDEWEB)

    Waddoup, W D; Stubbs, R J [Durham Univ. (UK)

    1977-11-01

    An eight channel 64-bit scaler has been constructed with a static CMOS memory. Scaling frequencies are independently variable, at each channel, as are the number of bits/channel. The scaler, when used in conjunction with a multichannel charge to time converter results in a very flexible, gated multichannel ADC.

  18. KV7 potassium channels

    DEFF Research Database (Denmark)

    Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

    2014-01-01

    Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

  19. Functional high-resolution computed tomography of pulmonary vascular and airway reactions. Experimental results. Funktionelle HR-CT der Lunge. Experimentelle Untersuchungen pulmonaler Gefaess- und Atemwegsreaktionen

    Energy Technology Data Exchange (ETDEWEB)

    Herold, C.J. (Universitaetsklinik fuer Radiodiagnostik, Vienna (Austria) Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Radiology); Brown, R.H. (Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Radiology Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Anesthesiology and Intensive Care Medicine Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Physiology); Wetzel, R.C.; Herold, S.M. (Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Anesthesiology and Intensive Care Medicine); Zeerhouni, E.A. (Johns Hopkins Medical Institutions, Baltimore, MD (United States). Dept. of Radiology)

    1993-03-01

    We describe the use of high-resolution computed tomography (HRCT) for assessment of the function of pulmonary vessels and airways. With its excellent spatial resolution, HRCT is able to demonstrate pulmonary structures as small as 300 [mu]m and can be used to monitor changes following various stimuli. HRCT also provides information about structures smaller than 300 [mu]m through measurement of parenchymal background density. To date, sequential, spiral and ultrafast HRCT techniques have been used in a variety of challenges to gather information about the anatomical correlates of traditional physiological measurements, thus making anatomical-physiological correlation possible. HRCT of bronchial reactivity can demonstrate the location and time course of aerosol-induced broncho-constriction and may show changes not apparent on spirometry. HRCT of the pulmonary vascular system visualized adaptations of vessels during hypoxia and intravascular volume loading and elucidates cardiorespiratory interactions. Experimental studies provide a basis for potential clinical applications of this method. (orig.).

  20. Coronary arterial BK channel dysfunction exacerbates ischemia/reperfusion-induced myocardial injury in diabetic mice.

    Science.gov (United States)

    Lu, Tong; Jiang, Bin; Wang, Xiao-Li; Lee, Hon-Chi

    2016-09-01

    The large conductance Ca(2+)-activated K(+) (BK) channels, abundantly expressed in coronary artery smooth muscle cells (SMCs), play a pivotal role in regulating coronary circulation. A large body of evidence indicates that coronary arterial BK channel function is diminished in both type 1 and type 2 diabetes. However, the consequence of coronary BK channel dysfunction in diabetes is not clear. We hypothesized that impaired coronary BK channel function exacerbates myocardial ischemia/reperfusion (I/R) injury in streptozotocin-induced diabetic mice. Combining patch-clamp techniques and cellular biological approaches, we found that diabetes facilitated the colocalization of angiotensin II (Ang II) type 1 receptors and BK channel α-subunits (BK-α), but not BK channel β1-subunits (BK-β1), in the caveolae of coronary SMCs. This caveolar compartmentation in vascular SMCs not only enhanced Ang II-mediated inhibition of BK-α but also produced a physical disassociation between BK-α and BK-β1, leading to increased infarct size in diabetic hearts. Most importantly, genetic ablation of caveolae integrity or pharmacological activation of coronary BK channels protected the cardiac function of diabetic mice from experimental I/R injury in both in vivo and ex vivo preparations. Our results demonstrate a vascular ionic mechanism underlying the poor outcome of myocardial injury in diabetes. Hence, activation of coronary BK channels may serve as a therapeutic target for cardiovascular complications of diabetes.

  1. Angiogenesis, Cancer, and Vascular Aging

    Directory of Open Access Journals (Sweden)

    Junji Moriya

    2017-10-01

    Full Text Available Several lines of evidence have revealed that the angiogenic response to ischemic injury declines with age, which might account for the increased morbidity and mortality of cardiovascular disease (CVD among the elderly. While impairment of angiogenesis with aging leads to delayed wound healing or exacerbation of atherosclerotic ischemic diseases, it also inhibits the progression of cancer. Age-related changes of angiogenesis have been considered to at least partly result from vascular aging or endothelial cell senescence. There is considerable evidence supporting the hypothesis that vascular cell senescence contributes to the pathogenesis of age-related CVD, suggesting that vascular aging could be an important therapeutic target. Since therapeutic angiogenesis is now regarded as a promising concept for patients with ischemic CVD, it has become even more important to understand the detailed molecular mechanisms underlying impairment of angiogenesis in older patients. To improve the usefulness of therapeutic angiogenesis, approaches are needed that can compensate for impaired angiogenic capacity in the elderly while not promoting the development or progression of malignancy. In this review, we briefly outline the mechanisms of angiogenesis and vascular aging, followed by a description of how vascular aging leads to impairment of angiogenesis. We also examine potential therapeutic approaches that could enhance angiogenesis and/or vascular function in the elderly, as well as discussing the possibility of anti-senescence therapy or reversal of endothelial cell senescence.

  2. Diclofenac distinguishes among homomeric and heteromeric potassium channels composed of KCNQ4 and KCNQ5 subunits.

    Science.gov (United States)

    Brueggemann, Lioubov I; Mackie, Alexander R; Martin, Jody L; Cribbs, Leanne L; Byron, Kenneth L

    2011-01-01

    KCNQ4 and KCNQ5 potassium channel subunits are expressed in vascular smooth muscle cells, although it remains uncertain how these subunits assemble to form functional channels. Using patch-clamp techniques, we compared the electrophysiological characteristics and effects of diclofenac, a known KCNQ channel activator, on human KCNQ4 and KCNQ5 channels expressed individually or together in A7r5 rat aortic smooth muscle cells. The conductance curves of the overexpressed channels were fitted by a single Boltzmann function in each case (V(0.5) values: -31, -44, and -38 mV for KCNQ4, KCNQ5, and KCNQ4/5, respectively). Diclofenac (100 μM) inhibited KCNQ5 channels, reducing maximum conductance by 53%, but increased maximum conductance of KCNQ4 channels by 38%. The opposite effects of diclofenac on KCNQ4 and KCNQ5 could not be attributed to the presence of a basic residue (lysine) in the voltage-sensing domain of KCNQ5, because mutation of this residue to neutral glycine (the residue present in KCNQ4) resulted in a more effective block of the channel. Differences in deactivation rates and distinct voltage-dependent effects of diclofenac on channel activation and deactivation observed with each of the subunit combinations (KCNQ4, KCNQ5, and KCNQ4/5) were used as diagnostic tools to evaluate native KCNQ currents in vascular smooth muscle cells. A7r5 cells express only KCNQ5 channels endogenously, and their responses to diclofenac closely resembled those of the overexpressed KCNQ5 currents. In contrast, mesenteric artery myocytes, which express both KCNQ4 and KCNQ5 channels, displayed whole-cell KCNQ currents with properties and diclofenac responses characteristic of overexpressed heteromeric KCNQ4/5 channels.

  3. Understanding the direction of the relationship between white matter hyperintensities of vascular origin, sleep quality, and chronic kidney disease-Results from the Atahualpa Project.

    Science.gov (United States)

    Del Brutto, Oscar H; Mera, Robertino M

    2018-02-01

    The burden of cerebral small vessel disease, sleep disorders, and chronic kidney disease is on the rise in remote rural settings. However, information on potential links between these conditions is limited. We aimed to assess the relationships between these conditions in community-dwelling older adults living in rural Ecuador. Atahualpa residents aged ≥60 years were offered a brain MRI. A venous blood sample was obtained for serum creatinine determination. Baseline interviews and procedures were directed to assess demographics, cardiovascular risk factors, and sleep quality. Using generalized structural equation modeling (GSEM), we assessed the associations between white matter hyperintensities (WMH) of vascular origin, sleep quality and kidney function, as well as the directions of the relationships between these variables. Of 423 candidates, 314 (74%) were enrolled. Moderate-to-severe WMH were noticed in 74 (24%) individuals, poor sleep quality in 101 (31%), and moderate-to-severe chronic kidney disease in 28 (9%). GSEM showed that the direction of the effect was from kidney function to WMH and from the latter to sleep quality. Of independent variables investigated, worse kidney function was associated with age, high glucose levels and male sex. WMH was associated with cholesterol blood levels, blood pressure, level of education and severe edentulism. Poor sleep quality was associated with poor physical activity. This population based study shows that chronic kidney disease is associated with increased severity of WMH, which, in turn, is associated with a poor sleep quality. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. International Benchmark on Pressurised Water Reactor Sub-channel and Bundle Tests. Volume II: Benchmark Results of Phase I: Void Distribution

    International Nuclear Information System (INIS)

    Rubin, Adam; Avramova, Maria; Velazquez-Lozada, Alexander

    2016-03-01

    This report summarised the first phase of the Nuclear Energy Agency (NEA) and the US Nuclear Regulatory Commission Benchmark based on NUPEC PWR Sub-channel and Bundle Tests (PSBT), which was intended to provide data for the verification of void distribution models in participants' codes. This phase was composed of four exercises; Exercise 1: steady-state single sub-channel benchmark, Exercise 2: steady-state rod bundle benchmark, Exercise 3: transient rod bundle benchmark and Exercise 4: a pressure drop benchmark. The experimental data provided to the participants of this benchmark is from a series of void measurement tests using full-size mock-up tests for both Boiling Water Reactors (BWRs) and Pressurised Water Reactors (PWRs). These tests were performed from 1987 to 1995 by the Nuclear Power Engineering Corporation (NUPEC) in Japan and made available by the Japan Nuclear Energy Safety Organisation (JNES) for the purposes of this benchmark, which was organised by Pennsylvania State University. Twenty-one institutions from nine countries participated in this benchmark. Seventeen different computer codes were used in Exercises 1, 2, 3 and 4. Among the computer codes were porous media, sub-channel, systems thermal-hydraulic code and Computational Fluid Dynamics (CFD) codes. It was observed that the codes tended to overpredict the thermal equilibrium quality at lower elevations and under predict it at higher elevations. There was also a tendency to overpredict void fraction at lower elevations and underpredict it at high elevations for the bundle test cases. The overprediction of void fraction at low elevations is likely caused by the x-ray densitometer measurement method used. Under sub-cooled boiling conditions, the voids accumulate at heated surfaces (and are therefore not seen in the centre of the sub-channel, where the measurements are being taken), so the experimentally-determined void fractions will be lower than the actual void fraction. Some of the best

  5. Fine Channel Networks

    Science.gov (United States)

    1997-01-01

    A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

  6. Results of tests and studies of American materials in the channel of the MHD facility U-02 (Phase III)

    International Nuclear Information System (INIS)

    Burenkov, D.K.; Borodina, T.I.; Vysotsky, D.A.; Zalkind, V.I.; Kirillov, V.V.; Romanov, A.I.; Telegin, G.P.; Strekalov, N.V.

    1978-10-01

    In accordance with the US--USSR Cooperative Program in MHD joint US--USSR tests were conducted in May 1978 at the U-02 facility of an MHD generator section consisting of U.S.-built electrode blocks and USSR-built insulating walls. The main purpose of the experiment was to conduct continuous 100-hour duration tests of materials and structures of electrode blocks; in particular, to study the behavior of ceramic electrodes and insulators in operating conditions of an MHD generator, the electro-physical and thermal characteristics of the working section as a whole and electrodes in particular, and to analyze the change in the phase composition and structure of materials during the test. The main thrust of the experiment was a study of electrode material behavior. Six varieties of electrodes based on doped lanthanum chromite were tested and investigated. The electrodes were made of fine grained, hot-pressed mass (the porosity of the ceramic was 2 to 3%). The interelectrode insulators were made of magnesial and magnesial-spinel ceramic also manufactured by the hot pressing method. Results are presented and discussed

  7. A mutation in the gene encoding mitochondrial Mg²+ channel MRS2 results in demyelination in the rat.

    Directory of Open Access Journals (Sweden)

    Takashi Kuramoto

    2011-01-01

    Full Text Available The rat demyelination (dmy mutation serves as a unique model system to investigate the maintenance of myelin, because it provokes severe myelin breakdown in the central nervous system (CNS after normal postnatal completion of myelination. Here, we report the molecular characterization of this mutation and discuss the possible pathomechanisms underlying demyelination. By positional cloning, we found that a G-to-A transition, 177 bp downstream of exon 3 of the Mrs2 (MRS2 magnesium homeostasis factor (Saccharomyces cerevisiae gene, generated a novel splice acceptor site which resulted in functional inactivation of the mutant allele. Transgenic rescue with wild-type Mrs2-cDNA validated our findings. Mrs2 encodes an essential component of the major Mg²+ influx system in mitochondria of yeast as well as human cells. We showed that the dmy/dmy rats have major mitochondrial deficits with a markedly elevated lactic acid concentration in the cerebrospinal fluid, a 60% reduction in ATP, and increased numbers of mitochondria in the swollen cytoplasm of oligodendrocytes. MRS2-GFP recombinant BAC transgenic rats showed that MRS2 was dominantly expressed in neurons rather than oligodendrocytes and was ultrastructurally observed in the inner membrane of mitochondria. Our observations led to the conclusion that dmy/dmy rats suffer from a mitochondrial disease and that the maintenance of myelin has a different mechanism from its initial production. They also established that Mg²+ homeostasis in CNS mitochondria is essential for the maintenance of myelin.

  8. Vascular dysfunction in preeclampsia.

    Science.gov (United States)

    Brennan, Lesley J; Morton, Jude S; Davidge, Sandra T

    2014-01-01

    Preeclampsia is a complex disorder which affects an estimated 5% of all pregnancies worldwide. It is diagnosed by hypertension in the presence of proteinuria after the 20th week of pregnancy and is a prominent cause of maternal morbidity and mortality. As delivery is currently the only known treatment, preeclampsia is also a leading cause of preterm delivery. Preeclampsia is associated with maternal vascular dysfunction, leading to serious cardiovascular risk both during and following pregnancy. Endothelial dysfunction, resulting in increased peripheral resistance, is an integral part of the maternal syndrome. While the cause of preeclampsia remains unknown, placental ischemia resulting from aberrant placentation is a fundamental characteristic of the disorder. Poor placentation is believed to stimulate the release of a number of factors including pro- and antiangiogenic factors and inflammatory activators into the maternal systemic circulation. These factors are critical mediators of vascular function and impact the endothelium in distinctive ways, including enhanced endothelial oxidative stress. The mechanisms of action and the consequences on the maternal vasculature will be discussed in this review. © 2013 John Wiley & Sons Ltd.

  9. The KATP channel in migraine pathophysiology

    DEFF Research Database (Denmark)

    Al-Karagholi, Mohammad Al-Mahdi; Hansen, Jakob Møller; Severinsen, Johanne

    2017-01-01

    BACKGROUND: To review the distribution and function of KATP channels, describe the use of KATP channels openers in clinical trials and make the case that these channels may play a role in headache and migraine. DISCUSSION: KATP channels are widely present in the trigeminovascular system and play...... an important role in the regulation of tone in cerebral and meningeal arteries. Clinical trials using synthetic KATP channel openers report headache as a prevalent-side effect in non-migraine sufferers, indicating that KATP channel opening may cause headache, possibly due to vascular mechanisms. Whether KATP...... channel openers can provoke migraine in migraine sufferers is not known. CONCLUSION: We suggest that KATP channels may play an important role in migraine pathogenesis and could be a potential novel therapeutic anti-migraine target....

  10. Vascular dementia | Connor | African Journal of Psychiatry

    African Journals Online (AJOL)

    Vascular dementia (VaD) is a common but heterogeneous condition in which there is a clear temporal relationship between the dementia and vascular disease. It may result from multiple large or small vessel strokes or a single strategic stroke. Subcortical ischaemic VaD includes multiple lacunes and subcortical ...

  11. Vascular Gene Expression: A Hypothesis

    Directory of Open Access Journals (Sweden)

    Angélica Concepción eMartínez-Navarro

    2013-07-01

    Full Text Available The phloem is the conduit through which photoassimilates are distributed from autotrophic to heterotrophic tissues and is involved in the distribution of signaling molecules that coordinate plant growth and responses to the environment. Phloem function depends on the coordinate expression of a large array of genes. We have previously identified conserved motifs in upstream regions of the Arabidopsis genes, encoding the homologs of pumpkin phloem sap mRNAs, displaying expression in vascular tissues. This tissue-specific expression in Arabidopsis is predicted by the overrepresentation of GA/CT-rich motifs in gene promoters. In this work we have searched for common motifs in upstream regions of the homologous genes from plants considered to possess a primitive vascular tissue (a lycophyte, as well as from others that lack a true vascular tissue (a bryophyte, and finally from chlorophytes. Both lycophyte and bryophyte display motifs similar to those found in Arabidopsis with a significantly low E-value, while the chlorophytes showed either a different conserved motif or no conserved motif at all. These results suggest that these same genes are expressed coordinately in non- vascular plants; this coordinate expression may have been one of the prerequisites for the development of conducting tissues in plants. We have also analyzed the phylogeny of conserved proteins that may be involved in phloem function and development. The presence of CmPP16, APL, FT and YDA in chlorophytes suggests the recruitment of ancient regulatory networks for the development of the vascular tissue during evolution while OPS is a novel protein specific to vascular plants.

  12. Diclofenac Distinguishes among Homomeric and Heteromeric Potassium Channels Composed of KCNQ4 and KCNQ5 SubunitsS⃞

    Science.gov (United States)

    Brueggemann, Lioubov I.; Mackie, Alexander R.; Martin, Jody L.; Cribbs, Leanne L.

    2011-01-01

    KCNQ4 and KCNQ5 potassium channel subunits are expressed in vascular smooth muscle cells, although it remains uncertain how these subunits assemble to form functional channels. Using patch-clamp techniques, we compared the electrophysiological characteristics and effects of diclofenac, a known KCNQ channel activator, on human KCNQ4 and KCNQ5 channels expressed individually or together in A7r5 rat aortic smooth muscle cells. The conductance curves of the overexpressed channels were fitted by a single Boltzmann function in each case (V0.5 values: −31, −44, and −38 mV for KCNQ4, KCNQ5, and KCNQ4/5, respectively). Diclofenac (100 μM) inhibited KCNQ5 channels, reducing maximum conductance by 53%, but increased maximum conductance of KCNQ4 channels by 38%. The opposite effects of diclofenac on KCNQ4 and KCNQ5 could not be attributed to the presence of a basic residue (lysine) in the voltage-sensing domain of KCNQ5, because mutation of this residue to neutral glycine (the residue present in KCNQ4) resulted in a more effective block of the channel. Differences in deactivation rates and distinct voltage-dependent effects of diclofenac on channel activation and deactivation observed with each of the subunit combinations (KCNQ4, KCNQ5, and KCNQ4/5) were used as diagnostic tools to evaluate native KCNQ currents in vascular smooth muscle cells. A7r5 cells express only KCNQ5 channels endogenously, and their responses to diclofenac closely resembled those of the overexpressed KCNQ5 currents. In contrast, mesenteric artery myocytes, which express both KCNQ4 and KCNQ5 channels, displayed whole-cell KCNQ currents with properties and diclofenac responses characteristic of overexpressed heteromeric KCNQ4/5 channels. PMID:20876743

  13. Vascular grading of angiogenesis

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Sørensen, Flemming Brandt

    2000-01-01

    The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer....

  14. Vascular grading of angiogenesis

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Sørensen, Flemming Brandt

    2000-01-01

    The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... impact for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer....

  15. Inward rectifier potassium (Kir2.1) channels as end-stage boosters of endothelium-dependent vasodilators.

    Science.gov (United States)

    Sonkusare, Swapnil K; Dalsgaard, Thomas; Bonev, Adrian D; Nelson, Mark T

    2016-06-15

    Increase in endothelial cell (EC) calcium activates calcium-sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium-dependent vasodilatation. Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium-dependent vasodilatation is not clear. In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform. Endothelium-dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown. These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Endothelium-dependent vasodilators, such as acetylcholine, increase intracellular Ca(2+) through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca(2+) -sensitive intermediate and small conductance K(+) (IK and SK, respectively) channels. Although strong inward rectifier K(+) (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC-dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC-dependent vasodilatation of resistance-sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC-specific Kir2.1 knockdown (EC-Kir2.1(-/-) ) mice. Elevation of extracellular K(+) to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial denudation and Kir channel

  16. Effect of gamma rays on electrically evoked contractions of non-vascular smooth muscles (rat vas deferens)

    International Nuclear Information System (INIS)

    Azroony, R.; Ksies, F.; Alya, G.

    2002-10-01

    We have tried, in this experiment, to study the modifications of non-vascular smooth muscles contraction induced via gamma rays. Smooth muscular fibers were isolated from the vas deferens of an adult rat and contractions were electrically evoked. Our results show that irradiation activates the VOC (Voltage Operated Channel) type of ionic channels which causes an increasing in the inward flux of Ca 2+ and then causes an increasing in the inner calcium concentration [Ca 2] i, the matter which means an increasing in the force of muscular contraction. Concerning to the response of vas deferens smooth muscles to the activation of membrane receptors, we have tried to study the effects of gamma rays on activating adrenergic and cholinergic receptors, also, we have tried to show the effects of different doses of gamma rays (1, 3, 5, 7 Gy) on regulating the contractile response of this type of smooth muscles. And results show that: - Irradiation increases contraction force, mediated by adrenergic and cholinergic receptors, in a dose dependent manner, with E m ax 1 Gy m axc 3 Gy m ax 5 Gy m ax 7 Gy. There is an important shift on irradiated rats (3, 5, 7 Gy) where the maximum effect of Acetylcholine (E m ax) can be obtained in lower concentrations of Acetylcholine. These results mean that irradiation activates the inward flux of Ca 2+ through the ROC (Receptors Operated Channels) type of ionic channels, which rely, in their activation, on activating the membrane receptors. By comparing these results with the effects of gamma rays on activating vascular adrenergic and cholinergic receptors, we concluded that: Non-vascular smooth muscles (vas deferens) are less sensitive to irradiation in comparing with vascular smooth muscles (venae portal hepatica), and irradiation increases the sensitivity of cholinergic receptors to acetylcholine in the smooth muscular fibers of vas deferens while; if decreases this sensitivity in the smooth muscular fibers of venae portal hepatica

  17. Punctuated sediment record resulting from channel migration in a shallow sand-dominated micro-tidal lagoon, Northern Wadden Sea, Denmark

    DEFF Research Database (Denmark)

    Fruergaard, M.; Andersen, T.J.; Nielsen, L.H.

    2011-01-01

    depositional environment, but tidal channel sediments dominate in the five sediment cores, making up 56% of the 15 mof sediment core. Sedimentation in the lagoon alternated between slow vertical aggradation of sand flats (1.5–2 mm yr-1) and very fast lateral progradation of point bars in tidal channels, which...... caused the formation of a punctuated lagoonal fill. Frequent and comprehensive reworking of the sand flat sediments by tidal channel migration entails loss of sedimentary structures and bioturbation related to sand flat deposits, and old sand flat sediments are only very sparsely preserved. We further...... conclude that long-term (millennial timescale) sediment accumulation in the lagoon was controlled by rising sea-level, whereas short-term (centurial timescale) sediment accumulation was controlled by local erosion and depositional events caused by lateral migration of channels. Records of short-term sea...

  18. Channeling experiment

    International Nuclear Information System (INIS)

    Abelin, H.; Birgersson, L.; Widen, H.; Aagren, T.; Moreno, L.; Neretnieks, I.

    1990-07-01

    Channeling of water flow and tracer transport in real fractures in a granite body at Stripa have been investigated experimentally. The experimental site was located 360 m below the ground level. Two kinds of experiments were performed. In the single hole experiments, 20 cm diameter holes were drilled about 2.5 m into the rock in the plane of the fracture. Specially designed packers were used to inject water into the fracture in 5 cm intervals all along the fracture trace in the hole. The variation of the injection flowrates along the fracture were used to determine the transmissivity variations in the fracture plane. Detailed photographs were taken from inside the hole and the visual fracture aperture was compared with the injection flowrates in the same locations. Geostatistical methods were used to evaluate the results. Five holes were measured in great detail. In addition 7 holes were drilled and scanned by simpler packer systems. A double hole experiment was performed where two parallel holes were drilled in the same fracture plane at nearly 2 m distance. Pressure pulse tests were made between the holes in both directions. Tracers were injected in 5 locations in one hole and monitored for in many locations in the other hole. The single hole experiment and the double hole experiment show that most of the fracture planes are tight but that there are open sections which form connected channels over distances of at least 2 meters. It was also found in the double hole experiment that the investigated fracture was intersected by at least one fracture between the two holes which diverted a large amount of the injected tracers to several distant locations at the tunnel wall. (authours)

  19. Image Quality in Vascular Radiology

    International Nuclear Information System (INIS)

    Vanhavere, F.; Struelens, L.

    2005-01-01

    In vascular radiology, the radiologists use the radiological image to diagnose or treat a specific vascular structure. From literature, we know that related doses are high and that large dose variability exists between different hospitals. The application of the optimization principle is therefore necessary and is obliged by the new legislation. So far, very little fieldwork has been performed and no practical instructions are available to do the necessary work. It's indisputable that obtaining quantitative data is of great interest for optimization purposes. In order to gain insight into these doses and the possible measures for dose reduction, we performed a comparative study in 7 hospitals. Patient doses will be measured and calculated for specific procedures in vascular radiology and evaluated against their most influencing parameters. In view of optimization purposes, a protocol for dose audit will be set-up. From the results and conclusions in this study, experimentally based guidelines will be proposed, in order to improve clinical practice in vascular radiology

  20. The evolution of development of vascular cambia and secondary growth

    Science.gov (United States)

    Andrew Groover; Rachel Spicer

    2010-01-01

    Secondary growth from vascular cambia results in radial, woody growth of stems. The innovation of secondary vascular development during plant evolution allowed the production of novel plant forms ranging from massive forest trees to flexible, woody lianas. We present examples of the extensive phylogenetic variation in secondary vascular growth and discuss current...

  1. Vascular Access in Children

    International Nuclear Information System (INIS)

    Krishnamurthy, Ganesh; Keller, Marc S.

    2011-01-01

    Establishment of stable vascular access is one of the essential and most challenging procedures in a pediatric hospital. Many clinical specialties provide vascular service in a pediatric hospital. At the top of the “expert procedural pyramid” is the pediatric interventional radiologist, who is best suited and trained to deliver this service. Growing awareness regarding the safety and high success rate of vascular access using image guidance has led to increased demand from clinicians to provide around-the-clock vascular access service by pediatric interventional radiologists. Hence, the success of a vascular access program, with the pediatric interventional radiologist as the key provider, is challenging, and a coordinated multidisciplinary team effort is essential for success. However, there are few dedicated pediatric interventional radiologists across the globe, and also only a couple of training programs exist for pediatric interventions. This article gives an overview of the technical aspects of pediatric vascular access and provides useful tips for obtaining vascular access in children safely and successfully using image guidance.

  2. Pediatric vascular access

    International Nuclear Information System (INIS)

    Donaldson, James S.

    2006-01-01

    Pediatric interventional radiologists are ideally suited to provide vascular access services to children because of inherent safety advantages and higher success from using image-guided techniques. The performance of vascular access procedures has become routine at many adult interventional radiology practices, but this service is not as widely developed at pediatric institutions. Although interventional radiologists at some children's hospitals offer full-service vascular access, there is little or none at others. Developing and maintaining a pediatric vascular access service is a challenge. Interventionalists skilled in performing such procedures are limited at pediatric institutions, and institutional support from clerical staff, nursing staff, and technologists might not be sufficiently available to fulfill the needs of such a service. There must also be a strong commitment by all members of the team to support such a demanding service. There is a slippery slope of expected services that becomes steeper and steeper as the vascular access service grows. This review is intended primarily as general education for pediatric radiologists learning vascular access techniques. Additionally, the pediatric or adult interventional radiologist seeking to expand services might find helpful tips. The article also provides education for the diagnostic radiologist who routinely interprets radiographs containing vascular access devices. (orig.)

  3. The vascular flora of a section of the transformed Piwonia River channel - the surrounding ditch on Lake Bikcze (Łęczna-Włodawa Lakeland - in relation to habitat conditions

    Directory of Open Access Journals (Sweden)

    Magdalena Pogorzelec

    2012-12-01

    Full Text Available In the period 2007-2009, floristic, habitat and physico- chemical analysis was made of the hydraulically improved surrounding ditch of Lake Bikcze in the Łęczna-Włodawa Lakeland. Hemicryptophytes, with a large proportion of geophytes as well as hydrophytes and helophytes, were the main component of the flora of the studied section of the transformed Piwonia River channel. In terms of historical-geographical classification, spontaneophytes were predominant, and apophytes among them, whereas anthropophytes were poorly represented, which was confirmed by the correspondingly high values of the synanthropization and apophytization indices (> 50% as well as the low value of the anthropophytization index (approx. 2%. In the aspect of the range of occurrence, Euro-Siberian and cosmopolitan species were predominant, which are classified in terms of the indicator values as hygrophilous plants, neutral to continentality, living in moderately cool or moderately warm climatic conditions, characterized by a wide range of tolerance to the trophic state index and to soil acidity. An analysis of the values of the basic physico-chemical factors of the stagnant water in the surrounding ditch showed variations in the value of pH, electrolytic conductivity and the value of the concentration of organic and ammonium nitrogen as well as of organic phosphorus and phosphates. In spite of the anthropogenic nature of the studied watercourse, the qualitative and quantitative proportions of the flora species indicated the natural state of the flora based on the native vegetation, characteristic of the study area.

  4. Vascular malformations in pediatrics

    International Nuclear Information System (INIS)

    Reith, W.; Shamdeen, M.G.

    2003-01-01

    Vascular malformations are the cause of nearly all non-traumatic intracranial hemorrhage in children beyond the neonatal stage. Therefore, any child presenting with spontaneous intracranial hemorrhage should be evaluated for child abuse and for vascular malformations. Intracerebral malformations of the cerebral vasculature include vein of Galen malformations, arteriovenous malformation (AVM), cavernomas, dural arteriovenous fistulas, venous anomalies (DVA), and capillary teleangiectasies. Although a few familial vascular malformation have been reported, the majority are sporadic. Clinical symptoms, diagnostic and therapeutic options are discussed. (orig.) [de

  5. Evaluation of Effectiveness of Embolization in Pelvic Congestion Syndrome with the New Vascular Occlusion Device (ArtVentive EOS™): Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Pyra, Krzysztof, E-mail: k.pyra@poczta.fm [Medical University of Lublin, Department of Interventional Radiology and Neuroradiology (Poland); Woźniak, Sławomir, E-mail: slavwo7572@gmail.com [Medical University of Lublin, III Gynecology Clinic (Poland); Drelich-Zbroja, Anna, E-mail: zbroanna@interia.pl; Wolski, Andrzej, E-mail: andrzej.s.wolski@gmail.com; Jargiełło, Tomasz, E-mail: tojarg@interia.pl [Medical University of Lublin, Department of Interventional Radiology and Neuroradiology (Poland)

    2016-08-15

    PurposeThis study aimed to collect confirmatory data in support of the safety and efficiency of the ArtVentive EOS™ for the treatment of the pelvic congestion syndrome (PCS). This study was based on the OCCLUDE 1 Study Protocol approved by the Local Ethics Committee.Materials and MethodsA prospective study carried out in June and July 2014 included 12 women aged 21–48 years (mean 31 years) scheduled for PCS embolization using the ArtVentive EOS™. The inclusion criteria were clinical symptoms of PCS documented by transvaginal Doppler ultrasound and pelvic MRI. The pelvic pain was assessed by VAS score from 0 to 10 (0 represents lack of pain and 10 unbearable pain). A decrease in pelvic pain intensity based on the VAS was considered a clinical success.ResultsSuccessful embolization procedures with ArtVentive EOS™ were performed in 11 out of 12 patients. Nine patients underwent unilateral embolization of the left ovarian vein, and two had bilateral embolization of the ovarian veins. Complete ovarian vein occlusion confirmed by post deployment venography was achieved in all 11 patients. Procedures lasted from 19 to 45 min (average 28 min). Pain intensity decrease was observed in all 11 patients—a decrease of 5.6 points—from 7.3 pre-procedure to 1.6 post-embolization (standard deviation: 0.67). In one case, the left ovarian vein was injured by guide wire manipulation with contrast extravasation—not clinically significant.ConclusionsThe use of ArtVentive EOS™ for occlusion of the ovarian veins in PCS patients is safe and effective.

  6. Constitutive expression of DaCBF7, an Antarctic vascular plant Deschampsia antarctica CBF homolog, resulted in improved cold tolerance in transgenic rice plants.

    Science.gov (United States)

    Byun, Mi Young; Lee, Jungeun; Cui, Li Hua; Kang, Yoonjee; Oh, Tae Kyung; Park, Hyun; Lee, Hyoungseok; Kim, Woo Taek

    2015-07-01

    Deschampsia antarctica is an Antarctic hairgrass that grows on the west coast of the Antarctic peninsula. In this report, we have identified and characterized a transcription factor, D. antarctica C-repeat binding factor 7 (DaCBF7), that is a member of the monocot group V CBF homologs. The protein contains a single AP2 domain, a putative nuclear localization signal, and the typical CBF signature. DaCBF7, like other monocot group V homologs, contains a distinct polypeptide stretch composed of 43 amino acids in front of the AP2 motif. DaCBF7 was predominantly localized to nuclei and interacted with the C-repeat/dehydration responsive element (CRT/DRE) core sequence (ACCGAC) in vitro. DaCBF7 was induced by abiotic stresses, including drought, cold, and salinity. To investigate its possible cellular role in cold tolerance, a transgenic rice system was employed. DaCBF7-overexpressing transgenic rice plants (Ubi:DaCBF7) exhibited markedly increased tolerance to cold stress compared to wild-type plants without growth defects; however, overexpression of DaCBF7 exerted little effect on tolerance to drought or salt stress. Transcriptome analysis of a Ubi:DaCBF7 transgenic line revealed 13 genes that were up-regulated in DaCBF7-overexpressing plants compared to wild-type plants in the absence of cold stress and in short- or long-term cold stress. Five of these genes, dehydrin, remorin, Os03g63870, Os11g34790, and Os10g22630, contained putative CRT/DRE or low-temperature responsive elements in their promoter regions. These results suggest that overexpression of DaCBF7 directly and indirectly induces diverse genes in transgenic rice plants and confers enhanced tolerance to cold stress. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Evaluation of Effectiveness of Embolization in Pelvic Congestion Syndrome with the New Vascular Occlusion Device (ArtVentive EOS™): Preliminary Results

    International Nuclear Information System (INIS)

    Pyra, Krzysztof; Woźniak, Sławomir; Drelich-Zbroja, Anna; Wolski, Andrzej; Jargiełło, Tomasz

    2016-01-01

    PurposeThis study aimed to collect confirmatory data in support of the safety and efficiency of the ArtVentive EOS™ for the treatment of the pelvic congestion syndrome (PCS). This study was based on the OCCLUDE 1 Study Protocol approved by the Local Ethics Committee.Materials and MethodsA prospective study carried out in June and July 2014 included 12 women aged 21–48 years (mean 31 years) scheduled for PCS embolization using the ArtVentive EOS™. The inclusion criteria were clinical symptoms of PCS documented by transvaginal Doppler ultrasound and pelvic MRI. The pelvic pain was assessed by VAS score from 0 to 10 (0 represents lack of pain and 10 unbearable pain). A decrease in pelvic pain intensity based on the VAS was considered a clinical success.ResultsSuccessful embolization procedures with ArtVentive EOS™ were performed in 11 out of 12 patients. Nine patients underwent unilateral embolization of the left ovarian vein, and two had bilateral embolization of the ovarian veins. Complete ovarian vein occlusion confirmed by post deployment venography was achieved in all 11 patients. Procedures lasted from 19 to 45 min (average 28 min). Pain intensity decrease was observed in all 11 patients—a decrease of 5.6 points—from 7.3 pre-procedure to 1.6 post-embolization (standard deviation: 0.67). In one case, the left ovarian vein was injured by guide wire manipulation with contrast extravasation—not clinically significant.ConclusionsThe use of ArtVentive EOS™ for occlusion of the ovarian veins in PCS patients is safe and effective.

  8. Homocysteine-Lowering and Cardiovascular Disease Outcomes in Kidney Transplant Recipients: Primary Results from the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial

    Science.gov (United States)

    Bostom, Andrew G.; Carpenter, Myra A.; Kusek, John W.; Levey, Andrew S.; Hunsicker, Lawrence; Pfeffer, Marc A.; Selhub, Jacob; Jacques, Paul F.; Cole, Edward; Gravens-Mueller, Lisa; House, Andrew A.; Kew, Clifton; McKenney, Joyce L.; Pacheco-Silva, Alvaro; Pesavento, Todd; Pirsch, John; Smith, Stephen; Solomon, Scott; Weir, Matthew

    2015-01-01

    Background Kidney transplant recipients, like other patients with chronic kidney disease (CKD), experience excess risk of cardiovascular disease (CVD) and elevated total homocysteine (tHcy) concentrations. Observational studies of patients with CKD suggest increased homocysteine is a risk factor for CVD. The impact of lowering total homocysteine (tHcy) levels in kidney transplant recipients is unknown. Methods and Results In a double-blind controlled trial, we randomized 4110 stable kidney transplant recipients to a multivitamin that included either a high dose (n=2056) or low dose (n=2054) of folic acid, vitamin B6, and vitamin B12 to determine whether decreasing tHcy concentrations reduced the rate of the primary composite arteriosclerotic CVD outcome (myocardial infarction, stroke, CVD death, resuscitated sudden death, coronary artery or renal artery revascularization, lower extremity arterial disease, carotid endarterectomy or angioplasty, or abdominal aortic aneurysm repair). Mean follow-up was 4.0 years. Treatment with the high dose multivitamin reduced homocysteine but did not reduce the rates of the primary outcome (n= 547 total events; hazards ratio [95% confidence interval] = 0.99 [0.84–1.17]), or secondary outcomes of all-cause mortality (n=431 deaths; 1.04 [0.86–1.26]) or dialysis-dependent kidney failure (n=343 events; 1.15 [0.93–1.43]) compared to the low dose multivitamin. Conclusions Treatment with a high dose folic acid, B6, and B12 multivitamin in kidney transplant recipients did not reduce a composite cardiovascular disease outcome, all-cause mortality, or dialysis-dependent kidney failure despite significant reduction in homocysteine level. PMID:21482964

  9. Channel box

    International Nuclear Information System (INIS)

    Tanabe, Akira.

    1993-01-01

    In a channel box of a BWR type reactor, protruding pads are disposed in axial position on the lateral side of a channel box opposing to a control rod and facing the outer side portion of the control rod in a reactor core loaded state. In the initial loading stage of fuel assemblies, channel fasteners and spacer pads are abutted against each other in the upper portion between the channel boxes sandwiching the control rod therebetween. Further, in the lower portion, a gap as a channel for the movement of the control rod is ensured by the support of fuel support metals. If the channel box is bent toward the control rod along with reactor operation, the pads are abutted against each other to always ensure the gap through which the control rod can move easily. Further, when the pads are brought into contact with each other, the bending deformation of the channel box is corrected by urging to each other. Thus, the control rod can always be moved smoothly to attain reactor safety operation. (N.H.)

  10. Preliminary results of studies on the distribution of invasive alien vascular plant species occurring in semi-natural and natural habitats in NW Poland

    Directory of Open Access Journals (Sweden)

    Popiela Agnieszka

    2015-03-01

    -natural and natural habitats is two times lower, while that of holoagriophytes and hemiagriophytes is 56.3% and 43.7%, respectively. It seems that in the case of some invasive and potentially invasive species, a decrease in the number of their locations may be observed from the west to the east (e.g. for Acer negundo, Bromus carinatus, Clematis vitalba, Helianthus tuberosus, Lycium barbarum, Reynoutria japonica, Rosa rugosa, Vicia grandiflora. Distribution patterns for some species (e.g. for Parthenocytisus inserta or Xanthium albinum are indicative of a likely major role of the Odra River valley in the spreading of invasive species. It should be kept in mind that the area of the North-West Poland is poorly examined in terms of its flora, so the results provided in this paper are tentative. Nevertheless, the maps illustrate colonisation trends and directions and, moreover, have been so far the only attempt to synthesise this problem in NW Poland.

  11. Downregulation of Kv7.4 channel activity in primary and secondary hypertension

    DEFF Research Database (Denmark)

    Jepps, Thomas Andrew; Chadha, Preet S; Davis, Alison J

    2011-01-01

    Voltage-gated potassium (K(+)) channels encoded by KCNQ genes (Kv7 channels) have been identified in various rodent and human blood vessels as key regulators of vascular tone; however, nothing is known about the functional impact of these channels in vascular disease. We ascertained the effect of...... structurally different activators of Kv7.2 through Kv7.5 channels (BMS-204352, S-1, and retigabine) on blood vessels from normotensive and hypertensive animals.......Voltage-gated potassium (K(+)) channels encoded by KCNQ genes (Kv7 channels) have been identified in various rodent and human blood vessels as key regulators of vascular tone; however, nothing is known about the functional impact of these channels in vascular disease. We ascertained the effect of 3...

  12. Uterine Vascular Lesions

    Science.gov (United States)

    Vijayakumar, Abhishek; Srinivas, Amruthashree; Chandrashekar, Babitha Moogali; Vijayakumar, Avinash

    2013-01-01

    Vascular lesions of the uterus are rare; most reported in the literature are arteriovenous malformations (AVMs). Uterine AVMs can be congenital or acquired. In recent years, there has been an increasing number of reports of acquired vascular lesions of the uterus following pregnancy, abortion, cesarean delivery, and curettage. It can be seen from these reports that there is confusion concerning the terminology of uterine vascular lesions. There is also a lack of diagnostic criteria and management guidelines, which has led to an increased number of unnecessary invasive procedures (eg, angiography, uterine artery embolization, hysterectomy for abnormal vaginal bleeding). This article familiarizes readers with various vascular lesions of the uterus and their management. PMID:24340126

  13. Magnetic resonance vascular imaging

    International Nuclear Information System (INIS)

    Axel, L

    1989-01-01

    The basis principles of MRI are reviewed in order to understand how blood flow effects arise in conventional imaging. Then some of the ways these effects have ben used in MRI techniques specifically designed for vascular imaging, are considered. (author)

  14. Surface channeling

    International Nuclear Information System (INIS)

    Sizmann, R.; Varelas, C.

    1976-01-01

    There is experimental evidence that swift light ions incident at small angles towards single crystalline surfaces can lose an appreciable fraction of their kinetic energy during reflection. It is shown that these projectiles penetrate into the bulk surface region of the crystal. They can travel as channeled particles along long paths through the solid (surface channeling). The angular distribution and the depth history of the re-emerged projectiles are investigated by computer simulations. A considerable fraction of the penetrating projectiles re-emerges from the crystal with constant transverse energy if the angle of incidence is smaller than the critical angle for axial channeling. Analytical formulae are derived based on a diffusion model for surface channeling. A comparison with experimental data exhibits the relevance of the analytical solutions. (Auth.)

  15. results

    Directory of Open Access Journals (Sweden)

    Salabura Piotr

    2017-01-01

    Full Text Available HADES experiment at GSI is the only high precision experiment probing nuclear matter in the beam energy range of a few AGeV. Pion, proton and ion beams are used to study rare dielectron and strangeness probes to diagnose properties of strongly interacting matter in this energy regime. Selected results from p + A and A + A collisions are presented and discussed.

  16. Vascularized osseous graft for scaphoid

    International Nuclear Information System (INIS)

    Mendez Daza, Carlos Hernan; Mathoulin, Cristophe

    2004-01-01

    The most commonly used technique for treatment of pseudo-arthrosis of the scaphoid is osteo-synthesis with Kirschnet wires and cortical sponge grafts. Results reported by different teams using this procedure show no more than 90% osseous consolidation, especially in cases where vascularisation of the proximal fragment of the scaphoid is compromised. Here we present a series of ten cases of pseudo-arthrosis of the scaphoid, treated using a new surgical technique involving a vascularized osseous graft of the distal radius. Using this procedure we obtained 100% consolidation, with no complications either during the procedure or immediately post-operatively. Patients returned to work in week 15 on average. In 4 cases we observed discomfort in the area of the scar, which was successfully treated using local cortisone injection. The results obtained are very similar to those seen in the literature on the different techniques for vascularized osseous grafts for pseudo-arthrosis of the scaphoid

  17. Spark Channels

    Energy Technology Data Exchange (ETDEWEB)

    Haydon, S. C. [Department of Physics, University of New England, Armidale, NSW (Australia)

    1968-04-15

    A brief summary is given of the principal methods used for initiating spark channels and the various highly time-resolved techniques developed recently for studies with nanosecond resolution. The importance of the percentage overvoltage in determining the early history and subsequent development of the various phases of the growth of the spark channel is discussed. An account is then given of the recent photographic, oscillographic and spectroscopic investigations of spark channels initiated by co-axial cable discharges of spark gaps at low [{approx} 1%] overvoltages. The phenomena observed in the development of the immediate post-breakdown phase, the diffuse glow structure, the growth of the luminous filament and the final formation of the spark channel in hydrogen are described. A brief account is also given of the salient features emerging from corresponding studies of highly overvolted spark gaps in which the spark channel develops from single avalanche conditions. The essential differences between the two types of channel formation are summarized and possible explanations of the general features are indicated. (author)

  18. Aluminum exposure for one hour decreases vascular reactivity in conductance and resistance arteries in rats

    International Nuclear Information System (INIS)

    Schmidt, Patrícia Medeiros; Escobar, Alyne Goulart; Torres, João Guilherme Dini; Martinez, Caroline Silveira; Rizzetti, Danize Aparecida; Kunz, Simone Noremberg; Vassallo, Dalton Valentim; Alonso, María Jesús; Peçanha, Franck Maciel; Wiggers, Giulia Alessandra

    2016-01-01

    Aims: Aluminum (Al) is an important environmental contaminant; however, there are not enough evidences of Al-induced cardiovascular dysfunction. We investigated the effects of acute exposure to aluminum chloride (AlCl 3 ) on blood pressure, vascular reactivity and oxidative stress. Methods and results: Male Wistar rats were divided into two groups: Untreated: vehicle (ultrapure water, ip) and AlCl 3 : single dose of AlCl 3 (100 mg/kg,ip). Concentration-response curves to phenylephrine in the absence and presence of endothelium, the nitric oxide synthase inhibitor L-NAME, the potassium channel blocker tetraethylammonium, and the NADPH oxidase inhibitor apocynin were performed in segments from aortic and mesenteric resistance arteries. NO released was assessed in aorta and reactive oxygen species (ROS), malondialdehyde, non-protein thiol levels, antioxidant capacity and enzymatic antioxidant activities were investigated in plasma, aorta and/or mesenteric arteries. After one hour of AlCl 3 exposure serum Al levels attained 147.7 ± 25.0 μg/L. Al treatment: 1) did not affect blood pressure, heart rate and vasodilator responses induced by acetylcholine or sodium nitroprusside; 2) decreased phenylephrine-induced vasoconstrictor responses; 3) increased endothelial modulation of contractile responses, NO release and vascular ROS production from NADPH oxidase; 4) increased plasmatic, aortic and mesenteric malondialdehyde and ROS production, and 5) decreased antioxidant capacity and affected the antioxidant biomarkers non-protein thiol levels, glutathione peroxidase, glutathione-S-transferase, superoxide dismutase and catalase enzymatic activities. Conclusion: AlCl 3 -acute exposure reduces vascular reactivity. This effect is associated with increased NO production, probably acting on K + channels, which seems to occur as a compensatory mechanism against Al-induced oxidative stress. Our results suggest that Al exerts toxic effects to the vascular system. - Highlights:

  19. Aluminum exposure for one hour decreases vascular reactivity in conductance and resistance arteries in rats

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Patrícia Medeiros; Escobar, Alyne Goulart; Torres, João Guilherme Dini; Martinez, Caroline Silveira; Rizzetti, Danize Aparecida; Kunz, Simone Noremberg [Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul (Brazil); Vassallo, Dalton Valentim [Department of Physiological Sciences, Universidade Federal do Espírito Santo, Espirito Santo (Brazil); Alonso, María Jesús [Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón (Spain); Peçanha, Franck Maciel [Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul (Brazil); Wiggers, Giulia Alessandra, E-mail: giuliawp@gmail.com [Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul (Brazil)

    2016-12-15

    Aims: Aluminum (Al) is an important environmental contaminant; however, there are not enough evidences of Al-induced cardiovascular dysfunction. We investigated the effects of acute exposure to aluminum chloride (AlCl{sub 3}) on blood pressure, vascular reactivity and oxidative stress. Methods and results: Male Wistar rats were divided into two groups: Untreated: vehicle (ultrapure water, ip) and AlCl{sub 3}: single dose of AlCl{sub 3} (100 mg/kg,ip). Concentration-response curves to phenylephrine in the absence and presence of endothelium, the nitric oxide synthase inhibitor L-NAME, the potassium channel blocker tetraethylammonium, and the NADPH oxidase inhibitor apocynin were performed in segments from aortic and mesenteric resistance arteries. NO released was assessed in aorta and reactive oxygen species (ROS), malondialdehyde, non-protein thiol levels, antioxidant capacity and enzymatic antioxidant activities were investigated in plasma, aorta and/or mesenteric arteries. After one hour of AlCl{sub 3} exposure serum Al levels attained 147.7 ± 25.0 μg/L. Al treatment: 1) did not affect blood pressure, heart rate and vasodilator responses induced by acetylcholine or sodium nitroprusside; 2) decreased phenylephrine-induced vasoconstrictor responses; 3) increased endothelial modulation of contractile responses, NO release and vascular ROS production from NADPH oxidase; 4) increased plasmatic, aortic and mesenteric malondialdehyde and ROS production, and 5) decreased antioxidant capacity and affected the antioxidant biomarkers non-protein thiol levels, glutathione peroxidase, glutathione-S-transferase, superoxide dismutase and catalase enzymatic activities. Conclusion: AlCl{sub 3}-acute exposure reduces vascular reactivity. This effect is associated with increased NO production, probably acting on K{sup +} channels, which seems to occur as a compensatory mechanism against Al-induced oxidative stress. Our results suggest that Al exerts toxic effects to the vascular

  20. Parallel inter channel interaction mechanisms

    International Nuclear Information System (INIS)

    Jovic, V.; Afgan, N.; Jovic, L.

    1995-01-01

    Parallel channels interactions are examined. For experimental researches of nonstationary regimes flow in three parallel vertical channels results of phenomenon analysis and mechanisms of parallel channel interaction for adiabatic condition of one-phase fluid and two-phase mixture flow are shown. (author)

  1. Gestión clínica en un servicio de angiología y cirugía vascular: Resultados de la aplicación de algoritmos de manejo clínico Clinical management in a vascular surgery unit: Results of the application of a clinical practice protocol

    Directory of Open Access Journals (Sweden)

    J. Juliá

    2003-10-01

    Full Text Available Objetivo: Analizar el impacto de la gestión clínica en los indicadores básicos de calidad en un servicio de cirugía vascular durante un período de 10 años. Métodos: Análisis retrospectivo de los indicadores asistenciales en el período 1990-2001 y la influencia que han tenido una guía de manejo clínico y la elaboración de unos estándares de calidad. Resultados: Los indicadores de calidad analizados mejoran al comparar ambos períodos. El nivel de seguridad asistencial medicoquirúrgico no se afectó por la aplicación de algoritmos de manejo y de guías de cuidados clínicos. Conclusiones: La gestión clínica basada en el binomio coste-calidad puede asegurar la eficiencia de un servicio y optimizar los recursos sin menoscabo de la calidad de los procedimientos asistenciales. Es posible definir el estándar de calidad por grupo de procedimientos, en función de la utilización de recursos hospitalarios y de las tasas de morbimortalidad.Objectives: The aim of this study was to analyze the impact of clinical management on quality indicators in a vascular surgery unit over a 10-year period. Methods: We performed a retrospective analysis of quality indicators from 1990 to 2001 and of the influence of a clinical practice protocol and standards of quality on these indicators. Results: Comparison of both periods revealed improvement in all the quality indicators. The safety of surgical procedures was unaffected by the application of management protocols and clinical pathways. Conclusions: Clinical management based on the cost-quality binomial can ensure the efficiency of a hospital unit without adversely affecting quality of care. Quality standards based on hospital resource use, morbidity and mortality can be defined for groups of procedures.

  2. Inhibition of coronary blood flow by a vascular waterfall mechanism.

    Science.gov (United States)

    Downey, J M; Kirk, E S

    1975-06-01

    The mechanism whereby systole inhibits coronary blood flow was examined. A branch of the left coronary artery was maximally dilated with an adenosine infusion, and the pressure-flow relationship was obtained for beating and arrested states. The pressure-flow curve for the arrested state was shifted toward higher pressures and in the range of pressures above peak ventricular pressure was linear and parallel to that for the arrested state. Below this range the curve for the beating state converged toward that for the arrested state and was convex to the pressure axis. These results were compared with a model of the coronary vasculature that consisted of numerous parallel channels, each responding to local intramyocardial pressure by forming vascular waterfalls. When intramyocardial pressure in the model was assigned values from zero at the epicardium to peak ventricular pressure at the endocardium, pressure-flow curves similar to the experimental ones resulted. Thus, we conclude that systole inhibits coronary perfusion by the formation of vascular waterfalls and that the intramyocardial pressures responsible for this inhibition do not significantly exceed peak ventricular pressure.

  3. Eficácia da fonoterapia em um caso de afasia expressiva decorrente de acidente vascular encefálico Speech therapy effectiveness in a case of expressive aphasia resulting from stroke

    Directory of Open Access Journals (Sweden)

    Letícia Regina Kunst

    2012-01-01

    Full Text Available O objetivo deste estudo de caso foi relatar e analisar o caso de um paciente afásico adulto em tratamento fonoaudiológico na clínica escola do Curso de Fonoaudiologia de uma instituição federal de ensino. O sujeito estudado é um paciente do sexo masculino, com 68 anos de idade, em tratamento na clínica escola desde maio de 2009, sendo que seu processo terapêutico foi analisado até dezembro de 2010. Quanto à história clínica, o paciente sofreu acidente vascular encefálico isquêmico no hemisfério esquerdo, em janeiro de 2009, quando repentinamente apresentou um quadro de mutismo. Após serem realizadas avaliações fonoaudiológicas, concluiu-se que o mesmo apresentava como hipótese diagnóstica "Afasia de expressão, oral e escrita, decorrente de acidente vascular encefálico isquêmico." Diante disto foi elaborado o planejamento terapêutico. Desde o início do processo de terapia foi possível observar evoluções linguísticas no paciente. O fato de o sujeito ter procurado atendimento fonoaudiológico 15 dias após o acometimento pelo acidente vascular encefálico, provavelmente foi um fator fundamental para sua boa recuperação, pois há um grau de recuperação espontânea em pacientes afásicos, porém a melhora é mínima sem o tratamento adequado. Em aproximadamente um mês de terapia fonoaudiológica, o paciente expandiu consideravelmente seu vocabulário. Apesar de a área lesada ser extensa e fundamental para a linguagem, observou-se avanços bastante positivos com a terapia. Deste modo, acredita-se que a intervenção fonoaudiológica precoce contribuiu, em grande parte, para a reorganização da atividade linguística, visto que o paciente comunica-se satisfatoriamente considerando a grande extensão de sua lesão.The purpose of this article was doing a report case of an aphasic client subjected to speech therapy in the clinic of a Speech Pathology and Audiology course of a federal university. The studied subject is

  4. The endothelial αENaC contributes to vascular endothelial function in vivo

    DEFF Research Database (Denmark)

    Tarjus, Antoine; Maase, Martina; Jeggle, Pia

    2017-01-01

    The Epithelial Sodium Channel (ENaC) is a key player in renal sodium homeostasis. The expression of α β γ ENaC subunits has also been described in the endothelium and vascular smooth muscle, suggesting a role in vascular function. We recently demonstrated that endothelial ENaC is involved in aldo......-mediated dilation. Our data suggest that endothelial αENaC contributes to vascular endothelial function in vivo....

  5. Constructal vascularized structures

    Science.gov (United States)

    Cetkin, Erdal

    2015-06-01

    Smart features such as self-healing and selfcooling require bathing the entire volume with a coolant or/and healing agent. Bathing the entire volume is an example of point to area (or volume) flows. Point to area flows cover all the distributing and collecting kinds of flows, i.e. inhaling and exhaling, mining, river deltas, energy distribution, distribution of products on the landscape and so on. The flow resistances of a point to area flow can be decreased by changing the design with the guidance of the constructal law, which is the law of the design evolution in time. In this paper, how the flow resistances (heat, fluid and stress) can be decreased by using the constructal law is shown with examples. First, the validity of two assumptions is surveyed: using temperature independent Hess-Murray rule and using constant diameter ducts where the duct discharges fluid along its edge. Then, point to area types of flows are explained by illustrating the results of two examples: fluid networks and heating an area. Last, how the structures should be vascularized for cooling and mechanical strength is documented. This paper shows that flow resistances can be decreased by morphing the shape freely without any restrictions or generic algorithms.

  6. Magnetic resonance venography of congenital vascular malformations of the extremities

    International Nuclear Information System (INIS)

    Laor, T.; Burrows, P.E.; Hoffer, F.A.

    1996-01-01

    Contrast angiography can demonstrate the vascular components of a vascular malformation, but can be technically challenging in small patients with complex venous anomalies. We reviewed the role of magnetic resonance venography (MRV) in the evaluation of children with predominantly low-flow, vascular malformations of the extremities. MRV (2D time-of-flight technique) and magnetic resonance (MR) imaging examinations were performed in ten young patients with congential predominantly low-flow vascular malformations of the extremities. MR imaging was used to characterize and determine the extent of the malformations, and MRV to evaluate the deep and superficial venous channels. In all patients, MRV studies were reviewed in conjunction with contrast angiograms, considered the gold standard, to confirm the findings. All signficant channel anomalies seen with contrast angiography were identified with MRV. In addition, MRV demonstrated some veins that were not intentionally opacified during contrast studies. MRV demonstrates both the superficial and deep conducting veins, whereas contrast angiography is a more directed study, evaluating only those channels intentionally opacified. Together, MR imaging and MRV data can non-invasively form the basis for determining the prognosis and choosing the individual treatment of congenital vascular malformations of the extremities. (orig.)

  7. Quantum communication under channel uncertainty

    International Nuclear Information System (INIS)

    Noetzel, Janis Christian Gregor

    2012-01-01

    This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

  8. Biomimicry, vascular restenosis and coronary stents.

    Science.gov (United States)

    Schwartz, R S; van der Giessen, W J; Holmes, D R

    1998-01-01

    Biomimicry is in its earliest stages and is being considered in the realm of tissue engineering. If arterial implants are to limit neointimal thickening, purely passive structures cannot succeed. Bioactivity must be present, either by pharmacologic intervention or by fabricating a 'living stent' that contains active cellular material. As tissue engineering evolves, useful solutions will emerge from applying this knowledge directly to vascular biologic problems resulting from angioplasty, stenting, and vascular prosthesis research.

  9. Functional and pharmacological consequences of the distribution of voltage-gated calcium channels in the renal blood vessels

    DEFF Research Database (Denmark)

    Hansen, P B L

    2013-01-01

    Calcium channel blockers are widely used to treat hypertension because they inhibit voltage-gated calcium channels that mediate transmembrane calcium influx in, for example, vascular smooth muscle and cardiomyocytes. The calcium channel family consists of several subfamilies, of which the L......-type is usually associated with vascular contractility. However, the L-, T- and P-/Q-types of calcium channels are present in the renal vasculature and are differentially involved in controlling vascular contractility, thereby contributing to regulation of kidney function and blood pressure. In the preglomerular...... vascular bed, all the three channel families are present. However, the T-type channel is the only channel in cortical efferent arterioles which is in contrast to the juxtamedullary efferent arteriole, and that leads to diverse functional effects of L- and T-type channel inhibition. Furthermore...

  10. Kcne4 Deletion Sex-Dependently Alters Vascular Reactivity

    DEFF Research Database (Denmark)

    Abbott, Geoffrey W; Jepps, Thomas A

    2016-01-01

    transcripts, with no striking sex-specific differences. However, Kv7.4 protein expression in females was twice that in males, and was reduced in both sexes by Kcne4 deletion. Our findings confirm a crucial role for KCNE4 in regulation of Kv7 channel activity to modulate vascular tone, and provide the first......Voltage-gated potassium (Kv) channels formed by Kv7 (KCNQ) α-subunits are recognized as crucial for vascular smooth muscle function, in addition to their established roles in the heart (Kv7.1) and the brain (Kv7.2-5). In vivo, Kv7 α-subunits are often regulated by KCNE subfamily ancillary (β...... known molecular mechanism for sex-specificity of this modulation that has important implications for vascular reactivity and may underlie sex-specific susceptibility to cardiovascular diseases....

  11. Protein Kinase C Inhibitors as Modulators of Vascular Function and Their Application in Vascular Disease

    Directory of Open Access Journals (Sweden)

    Raouf A. Khalil

    2013-03-01

    Full Text Available Blood pressure (BP is regulated by multiple neuronal, hormonal, renal and vascular control mechanisms. Changes in signaling mechanisms in the endothelium, vascular smooth muscle (VSM and extracellular matrix cause alterations in vascular tone and blood vessel remodeling and may lead to persistent increases in vascular resistance and hypertension (HTN. In VSM, activation of surface receptors by vasoconstrictor stimuli causes an increase in intracellular free Ca2+ concentration ([Ca2+]i, which forms a complex with calmodulin, activates myosin light chain (MLC kinase and leads to MLC phosphorylation, actin-myosin interaction and VSM contraction. Vasoconstrictor agonists could also increase the production of diacylglycerol which activates protein kinase C (PKC. PKC is a family of Ca2+-dependent and Ca2+-independent isozymes that have different distributions in various blood vessels, and undergo translocation from the cytosol to the plasma membrane, cytoskeleton or the nucleus during cell activation. In VSM, PKC translocation to the cell surface may trigger a cascade of biochemical events leading to activation of mitogen-activated protein kinase (MAPK and MAPK kinase (MEK, a pathway that ultimately increases the myofilament force sensitivity to [Ca2+]i, and enhances actin-myosin interaction and VSM contraction. PKC translocation to the nucleus may induce transactivation of various genes and promote VSM growth and proliferation. PKC could also affect endothelium-derived relaxing and contracting factors as well as matrix metalloproteinases (MMPs in the extracellular matrix further affecting vascular reactivity and remodeling. In addition to vasoactive factors, reactive oxygen species, inflammatory cytokines and other metabolic factors could affect PKC activity. Increased PKC expression and activity have been observed in vascular disease and in certain forms of experimental and human HTN. Targeting of vascular PKC using PKC inhibitors may function in

  12. The secret life of ion channels: Kv1.3 potassium channels and proliferation.

    Science.gov (United States)

    Pérez-García, M Teresa; Cidad, Pilar; López-López, José R

    2018-01-01

    Kv1.3 channels are involved in the switch to proliferation of normally quiescent cells, being implicated in the control of cell cycle in many different cell types and in many different ways. They modulate membrane potential controlling K + fluxes, sense changes in potential, and interact with many signaling molecules through their intracellular domains. From a mechanistic point of view, we can describe the role of Kv1.3 channels in proliferation with at least three different models. In the "membrane potential model," membrane hyperpolarization resulting from Kv1.3 activation provides the driving force for Ca 2+ influx required to activate Ca 2+ -dependent transcription. This model explains most of the data obtained from several cells from the immune system. In the "voltage sensor model," Kv1.3 channels serve mainly as sensors that transduce electrical signals into biochemical cascades, independently of their effect on membrane potential. Kv1.3-dependent proliferation of vascular smooth muscle cells (VSMCs) could fit this model. Finally, in the "channelosome balance model," the master switch determining proliferation may be related to the control of the Kv1.3 to Kv1.5 ratio, as described in glial cells and also in VSMCs. Since the three mechanisms cannot function independently, these models are obviously not exclusive. Nevertheless, they could be exploited differentially in different cells and tissues. This large functional flexibility of Kv1.3 channels surely gives a new perspective on their functions beyond their elementary role as ion channels, although a conclusive picture of the mechanisms involved in Kv1.3 signaling to proliferation is yet to be reached.

  13. CANDU channel flow verification

    International Nuclear Information System (INIS)

    Mazalu, N.; Negut, Gh.

    1997-01-01

    The purpose of this evaluation was to obtain accurate information on each channel flow that enables us to assess precisely the level of reactor thermal power and, for reasons of safety, to establish which channel is boiling. In order to assess the channel flow parameters, computer simulations were done with the NUCIRC code and the results were checked by measurements. The complete channel flow measurements were made in the zero power cold condition. In hot conditions there were made flow measurements using the Shut Down System 1 (SDS 1) flow devices from 0.1 % F.P. up to 100 % F.P. The NUCIRC prediction for CANDU channel flows and the measurements by Ultrasonic Flow Meter at zero power cold conditions and SDS 1 flow channel measurements at different reactor power levels showed an acceptable agreement. The 100 % F.P. average errors for channel flow of R, shows that suitable NUCIRC flow assessment can be made. So, it can be done a fair prediction of the reactor power distribution. NUCIRC can predict accurately the onset of boiling and helps to warn at the possible power instabilities at high powers or it can detect the flow blockages. The thermal hydraulic analyst has in NUCIRC a suitable tool to do accurate predictions for the thermal hydraulic parameters for different steady state power levels which subsequently leads to an optimal CANDU reactor operation. (authors)

  14. Complex Membrane Channel Blockade: A Unifying Hypothesis for the Prodromal and Acute Neuropsychiatric Sequelae Resulting from Exposure to the Antimalarial Drug Mefloquine

    Directory of Open Access Journals (Sweden)

    Jane C. Quinn

    2015-01-01

    Full Text Available The alkaloid toxin quinine and its derivative compounds have been used for many centuries as effective medications for the prevention and treatment of malaria. More recently, synthetic derivatives, such as the quinoline derivative mefloquine (bis(trifluoromethyl-(2-piperidyl-4-quinolinemethanol, have been widely used to combat disease caused by chloroquine-resistant strains of the malaria parasite, Plasmodium falciparum. However, the parent compound quinine, as well as its more recent counterparts, suffers from an incidence of adverse neuropsychiatric side effects ranging from mild mood disturbances and anxiety to hallucinations, seizures, and psychosis. This review considers how the pharmacology, cellular neurobiology, and membrane channel kinetics of mefloquine could lead to the significant and sometimes life-threatening neurotoxicity associated with mefloquine exposure. A key role for mefloquine blockade of ATP-sensitive potassium channels and connexins in the substantia nigra is considered as a unifying hypothesis for the pathogenesis of severe neuropsychiatric events after mefloquine exposure in humans.

  15. Preparation and features of polycaprolactone vascular grafts with the incorporated vascular endothelial growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Sevostyanova, V. V., E-mail: sevostyanova.victoria@gmail.com; Khodyrevskaya, Y. I.; Glushkova, T. V.; Antonova, L. V.; Kudryavtseva, Y. A.; Barbarash, O. L.; Barbarash, L. S. [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo (Russian Federation)

    2015-10-27

    The development of tissue-engineered small-diameter vascular grafts is an urgent issue in cardiovascular surgery. In this study, we assessed how the incorporation of the vascular endothelial growth factor (VEGF) affects morphological and mechanical properties of polycaprolactone (PCL) vascular grafts along with its release kinetics. Vascular grafts were prepared using two-phase electrospinning. In pursuing our aims, we performed scanning electron microscopy, mechanical testing, and enzyme-linked immunosorbent assay. Our results demonstrated the preservation of a highly porous structure and improvement of PCL/VEGF scaffold mechanical properties as compared to PCL grafts. A prolonged VEGF release testifies the use of this construct as a scaffold for tissue-engineered vascular grafts.

  16. MARKETING CHANNELS

    Directory of Open Access Journals (Sweden)

    Ljiljana Stošić Mihajlović

    2014-07-01

    Full Text Available Marketing channel is a set of entities and institutions, completion of distribution and marketing activities, attend the efficient and effective networking of producers and consumers. Marketing channels include the total flows of goods, money and information taking place between the institutions in the system of marketing, establishing a connection between them. The functions of the exchange, the physical supply and service activities, inherent in the system of marketing and trade. They represent paths which products and services are moving after the production, which will ultimately end up buying and eating by the user.

  17. Audit of the Danish national vascular database

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Jensen, L P; Schroeder, T V

    1996-01-01

    The accuracy of data contained in the Danish vascular database was compared with the case notes. A total of 100 case notes were reviewed for 11 pertinent variables in the database. A high error rate ranging from 2 to 34% was found. Also, approximately 10% of patients had never been entered into t...... into the vascular database. Further improvement of the Danish vascular database is necessary for its use as basis for reporting results.......The accuracy of data contained in the Danish vascular database was compared with the case notes. A total of 100 case notes were reviewed for 11 pertinent variables in the database. A high error rate ranging from 2 to 34% was found. Also, approximately 10% of patients had never been entered...

  18. Lipidomics in vascular health: current perspectives.

    Science.gov (United States)

    Kolovou, Genovefa; Kolovou, Vana; Mavrogeni, Sophie

    2015-01-01

    Identifying the mechanisms that convert a healthy vascular wall to an atherosclerotic wall is of major importance since the consequences may lead to a shortened lifespan. Classical risk factors (age, smoking, obesity, diabetes mellitus, hypertension, and dyslipidemia) may result in the progression of atherosclerotic lesions by processes including inflammation and lipid accumulation. Thus, the evaluation of blood lipids and the full lipid complement produced by cells, organisms, or tissues (lipidomics) is an issue of importance. In this review, we shall describe the recent progress in vascular health research using lipidomic advances. We will begin with an overview of vascular wall biology and lipids, followed by a short analysis of lipidomics. Finally, we shall focus on the clinical implications of lipidomics and studies that have examined lipidomic approaches and vascular health.

  19. The diaphragms of fenestrated endothelia: gatekeepers of vascular permeability and blood composition.

    Science.gov (United States)

    Stan, Radu V; Tse, Dan; Deharvengt, Sophie J; Smits, Nicole C; Xu, Yan; Luciano, Marcus R; McGarry, Caitlin L; Buitendijk, Maarten; Nemani, Krishnamurthy V; Elgueta, Raul; Kobayashi, Takashi; Shipman, Samantha L; Moodie, Karen L; Daghlian, Charles P; Ernst, Patricia A; Lee, Hong-Kee; Suriawinata, Arief A; Schned, Alan R; Longnecker, Daniel S; Fiering, Steven N; Noelle, Randolph J; Gimi, Barjor; Shworak, Nicholas W; Carrière, Catherine

    2012-12-11

    Fenestral and stomatal diaphragms are endothelial subcellular structures of unknown function that form on organelles implicated in vascular permeability: fenestrae, transendothelial channels, and caveolae. PV1 protein is required for diaphragm formation in vitro. Here, we report that deletion of the PV1-encoding Plvap gene in mice results in the absence of diaphragms and decreased survival. Loss of diaphragms did not affect the fenestrae and transendothelial channels formation but disrupted the barrier function of fenestrated capillaries, causing a major leak of plasma proteins. This disruption results in early death of animals due to severe noninflammatory protein-losing enteropathy. Deletion of PV1 in endothelium, but not in the hematopoietic compartment, recapitulates the phenotype of global PV1 deletion, whereas endothelial reconstitution of PV1 rescues the phenotype. Taken together, these data provide genetic evidence for the critical role of the diaphragms in fenestrated capillaries in the maintenance of blood composition. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Effects of ouabain on vascular reactivity

    Directory of Open Access Journals (Sweden)

    Vassallo D.V.

    1997-04-01

    Full Text Available Ouabain is an endogenous substance occurring in the plasma in the nanomolar range, that has been proposed to increase vascular resistance and induce hypertension. This substance acts on the a-subunit of Na+,K+-ATPase inhibiting the Na+-pump activity. In the vascular smooth muscle this effect leads to intracellular Na+ accumulation that reduces the activity of the Na+/Ca2+ exchanger and to an increased vascular tone. It was also suggested that circulating ouabain, even in the nanomolar range, sensitizes the vascular smooth muscle to vasopressor substances. We tested the latter hypothesis by studying the effects of ouabain in the micromolar and nanomolar range on phenylephrine (PE-evoked pressor responses. The experiments were performed in normotensive and hypertensive rats in vivo, under anesthesia, and in perfused rat tail vascular beds. The results showed that ouabain pretreatment increased the vasopressor responses to PE in vitro and in vivo. This sensitization after ouabain treatment was also observed in hypertensive animals which presented an enhanced vasopressor response to PE in comparison to normotensive animals. It is suggested that ouabain at nanomolar concentrations can sensitize vascular smooth muscle to vasopressor stimuli possibly contributing to increased tone in hypertension

  1. Vascular Adventitia Calcification and Its Underlying Mechanism.

    Directory of Open Access Journals (Sweden)

    Na Li

    Full Text Available Previous research on vascular calcification has mainly focused on the vascular intima and media. However, we show here that vascular calcification may also occur in the adventitia. The purpose of this work is to help elucidate the pathogenic mechanisms underlying vascular calcification. The calcified lesions were examined by Von Kossa staining in ApoE-/- mice which were fed high fat diets (HFD for 48 weeks and human subjects aged 60 years and older that had died of coronary heart disease, heart failure or acute renal failure. Explant cultured fibroblasts and smooth muscle cells (SMCswere obtained from rat adventitia and media, respectively. After calcification induction, cells were collected for Alizarin Red S staining. Calcified lesions were observed in the aorta adventitia and coronary artery adventitia of ApoE-/-mice, as well as in the aorta adventitia of human subjects examined. Explant culture of fibroblasts, the primary cell type comprising the adventitia, was successfully induced for calcification after incubation with TGF-β1 (20 ng/ml + mineralization media for 4 days, and the phenotype conversion vascular adventitia fibroblasts into myofibroblasts was identified. Culture of SMCs, which comprise only a small percentage of all cells in the adventitia, in calcifying medium for 14 days resulted in significant calcification.Vascular calcification can occur in the adventitia. Adventitia calcification may arise from the fibroblasts which were transformed into myofibroblasts or smooth muscle cells.

  2. Vasculo-Neuronal Coupling: Retrograde Vascular Communication to Brain Neurons.

    Science.gov (United States)

    Kim, Ki Jung; Ramiro Diaz, Juan; Iddings, Jennifer A; Filosa, Jessica A

    2016-12-14

    Continuous cerebral blood flow is essential for neuronal survival, but whether vascular tone influences resting neuronal function is not known. Using a multidisciplinary approach in both rat and mice brain slices, we determined whether flow/pressure-evoked increases or decreases in parenchymal arteriole vascular tone, which result in arteriole constriction and dilation, respectively, altered resting cortical pyramidal neuron activity. We present evidence for intercellular communication in the brain involving a flow of information from vessel to astrocyte to neuron, a direction opposite to that of classic neurovascular coupling and referred to here as vasculo-neuronal coupling (VNC). Flow/pressure increases within parenchymal arterioles increased vascular tone and simultaneously decreased resting pyramidal neuron firing activity. On the other hand, flow/pressure decreases evoke parenchymal arteriole dilation and increased resting pyramidal neuron firing activity. In GLAST-CreERT2; R26-lsl-GCaMP3 mice, we demonstrate that increased parenchymal arteriole tone significantly increased intracellular calcium in perivascular astrocyte processes, the onset of astrocyte calcium changes preceded the inhibition of cortical pyramidal neuronal firing activity. During increases in parenchymal arteriole tone, the pyramidal neuron response was unaffected by blockers of nitric oxide, GABA A , glutamate, or ecto-ATPase. However, VNC was abrogated by TRPV4 channel, GABA B , as well as an adenosine A 1 receptor blocker. Differently to pyramidal neuron responses, increases in flow/pressure within parenchymal arterioles increased the firing activity of a subtype of interneuron. Together, these data suggest that VNC is a complex constitutive active process that enables neurons to efficiently adjust their resting activity according to brain perfusion levels, thus safeguarding cellular homeostasis by preventing mismatches between energy supply and demand. We present evidence for vessel

  3. The redox protein thioredoxin-1 (Trx-1) increases hypoxia-inducible factor 1alpha protein expression: Trx-1 overexpression results in increased vascular endothelial growth factor production and enhanced tumor angiogenesis.

    Science.gov (United States)

    Welsh, Sarah J; Bellamy, William T; Briehl, Margaret M; Powis, Garth

    2002-09-01

    Hypoxia-inducible factor 1 (HIF-1), a heterodimer of HIF-1alpha and HIF-1beta subunits, is a transcriptional activator central to the cellular response to low oxygen that includes metabolic adaptation, angiogenesis, metastasis, and inhibited apoptosis. Thioredoxin-1 (Trx-1) is a small redox protein overexpressed in a number of human primary tumors. We have examined the effects of Trx-1 on HIF activity and the activation of downstream genes. Stable transfection of human breast carcinoma MCF-7 cells with human Trx-1 caused a significant increase in HIF-1alpha protein levels under both normoxic (20% oxygen) and hypoxic (1% oxygen) conditions. Trx-1 increased hypoxia-induced HIF-1 transactivation activity measured using a luciferase reporter under the control of the hypoxia response element. Changes in HIF-1alpha mRNA levels did not account for the changes observed at the protein level, and HIF-1beta protein levels did not change. Trx-1 transfection also caused a significant increase in the protein products of hypoxia-responsive genes, including vascular endothelial growth factor (VEGF) and nitric oxide synthase 2 in a number of different cell lines (MCF-7 human breast and HT29 human colon carcinomas and WEHI7.2 mouse lymphoma cells) under both normoxic and hypoxic conditions. The pattern of expression of the different isoforms of VEGF was not changed by Trx-1. Transfection of a redox-inactive Trx-1 (C32S/C35S) markedly decreased levels of HIF-1alpha protein, HIF-1 transactivating activity, and VEGF protein in MCF-7 cells compared with empty vector controls. In vivo studies using WEHI7.2 cells transfected with Trx-1 showed significantly increased tumor VEGF and angiogenesis. The results suggest that Trx-1 increases HIF-1alpha protein levels in cancer cells and increases VEGF production and tumor angiogenesis.

  4. Heritability of Retinal Vascular Fractals

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    2017-01-01

    , the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation. Results: The mean...... fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, P = 0.06), supporting that the study population was suitable for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, P = 0...

  5. Major Vascular Neurocognitive Disorder: A Reappraisal to Vascular Dementia

    Directory of Open Access Journals (Sweden)

    Emre Kumral

    2017-03-01

    Full Text Available Major vascular neurocognitive disorder (NCD is the second leading form of dementia after Alzheimer’s disease, accounting for 17-20% of all dementias. Vascular NCD is a progressive disease caused by reduced cerebral blood flow related to multiple large volume or lacunar infarcts that induce a sudden onset and stepwise decline in cognitive abilities. Despite its prevalence and clinical importance, there is still controversy in the terminology of vascular NCD. Only after the release of Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5 (2013 did the American Psychiatric Association define vascular dementia as “major vascular NCD”. This review includes an overview of risk factors, pathophysiology, types, diagnostic and clinical features of major vascular NCD, and current treatment options of vascular NCD regarding to DSM-5 criteria

  6. Ion channelling in diamond

    International Nuclear Information System (INIS)

    Derry, T.E.

    1978-06-01

    Diamond is one of the most extreme cases from a channelling point of view, having the smallest thermal vibration amplitude and the lowest atomic number of commonly-encountered crystals. These are the two parameters most important for determining channelling behaviour. It is of consiberable interest therefore to see how well the theories explaining and predicting the channeling properties of other substance, succeed with diamond. Natural diamond, although the best available form for these experiments, is rather variable in its physical properties. Part of the project was devoted to considering and solving the problem of obtaining reproducible results representative of the ideal crystal. Channelling studies were performed on several good crystals, using the Rutherford backscattering method. Critical angles for proton channelling were measured for incident energies from 0.6 to 4.5 MeV, in the three most open axes and three most open planes of the diamond structure, and for α-particle channelling at 0.7 and 1.0 MeV (He + ) in the same axes and planes. For 1.0 MeV protons, the crystal temperature was varied from 20 degrees Celsius to 700 degrees Celsius. The results are presented as curves of backscattered yield versus angle in the region of each axis or plane, and summarised in the form of tables and graphs. Generally the critical angles, axial minimum yields, and temperature dependence are well predicted by the accepted theories. The most valuable overall conclusion is that the mean thermal vibration amplitude of the atoms in a crytical determines the critical approach distance to the channel walls at which an ion can remain channelled, even when this distance is much smaller than the Thomas-Fermi screening distance of the atomic potential, as is the case in diamond. A brief study was made of the radiation damage caused by α-particle bombardment, via its effect on the channelling phenomenon. It was possible to hold damage down to negligible levels during the

  7. Chaos in quantum channels

    Energy Technology Data Exchange (ETDEWEB)

    Hosur, Pavan; Qi, Xiao-Liang [Department of Physics, Stanford University,476 Lomita Mall, Stanford, California 94305 (United States); Roberts, Daniel A. [Center for Theoretical Physics and Department of Physics, Massachusetts Institute of Technology,77 Massachusetts Ave, Cambridge, Massachusetts 02139 (United States); Yoshida, Beni [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada); Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena CA 91125 (United States)

    2016-02-01

    We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back up our results with numerics in two non-integrable models and analytic results in a perfect tensor network model of chaotic time evolution. These results show that the butterfly effect in quantum systems implies the information-theoretic definition of scrambling.

  8. T-type Ca(2+) channels and Autoregulation of Local Blood Flow

    DEFF Research Database (Denmark)

    Jensen, Lars Jørn; Nielsen, Morten Schak; Salomonsson, Max

    2017-01-01

    L-type voltage gated Ca(2+) channels are considered to be the primary source of calcium influx during the myogenic response. However, many vascular beds also express T-type voltage gated Ca(2+) channels. Recent studies suggest that these channels may also play a role in autoregulation. At low pre...

  9. 5,6-EET potently inhibits T-type calcium channels

    DEFF Research Database (Denmark)

    Cazade, M.; Bidaud, I.; Hansen, Pernille B. Lærkegaard

    2014-01-01

    T-type calcium channels (T-channels) are important actors in neuronal pacemaking, in heart rhythm, and in the control of the vascular tone. T-channels are regulated by several endogenous lipids including the primary eicosanoid arachidonic acid (AA), which display an important role in vasodilation...

  10. Plant Vascular Biology 2010

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Biao

    2014-11-17

    This grant supported the Second International Conference on Plant Vascular Biology (PVB 2010) held July 24-28, 2010 on the campus of Ohio State University, Columbus, Ohio. Biao Ding (Ohio State University; OSU) and David Hannapel (Iowa State University; ISU) served as co-chairs of this conference. Biao Ding served as the local organizer. PVB is defined broadly here to include studies on the biogenesis, structure and function of transport systems in plants, under conditions of normal plant growth and development as well as of plant interactions with pathogens. The transport systems cover broadly the xylem, phloem, plasmodesmata and vascular cell membranes. The PVB concept has emerged in recent years to emphasize the integrative nature of the transport systems and approaches to investigate them.

  11. Vascular cognitive impairment

    Directory of Open Access Journals (Sweden)

    N.V. Vakhnina

    2014-01-01

    Full Text Available Vascular pathology of the brain is the second most common cause of cognitive impairment after Alzheimer's disease. The article describes the modern concepts of etiology, pathogenetic mechanisms, clinical features and approaches to diagnosis and therapy of vascular cognitive impairment (VCI. Cerebrovascular accident, chronic cerebral circulatory insufficiency and their combination, sometimes in combination with a concomitant neurodegenerative process, are shown to be the major types of brain lesions leading to VCI. The clinical presentation of VCI is characterized by the neuropsychological status dominated by impairment of the executive frontal functions (planning, control, attention in combination with focal neurological symptoms. The diagnosis is based on comparing of the revealed neuropsychological and neurological features with neuroimaging data. Neurometabolic, acetylcholinergic, glutamatergic, and other vasoactive drugs and non-pharmacological methods are widely used to treat VCI. 

  12. Vascular Surgery and Robotics

    Directory of Open Access Journals (Sweden)

    Indrani Sen

    2016-01-01

    Full Text Available The application of robotics to Vascular surgery has not progressed as rapidly as of endovascular technology, but this is changing with the amalgamation of these two fields. The advent of Endovascular robotics is an exciting field which overcomes many of the limitations of endovascular therapy like vessel tortuosity and operator fatigue. This has much clinical appeal for the surgeon and hold significant promise of better patient outcomes. As with most newer technological advances, it is still limited by cost and availability. However, this field has seen some rapid progress in the last decade with the technology moving into the clinical realm. This review details the development of robotics, applications, outcomes, advantages, disadvantages and current advances focussing on Vascular and Endovascular robotics

  13. New Role of P/Q-type Voltage-gated Calcium Channels

    DEFF Research Database (Denmark)

    Hansen, Pernille B L

    2015-01-01

    Voltage-gated calcium channels are important for the depolarization-evoked contraction of vascular smooth muscle cells (SMCs), with L-type channels being the classical channel involved in this mechanism. However, it has been demonstrated that the CaV2.1 subunit, which encodes a neuronal isoform...... of the voltage-gated calcium channels (P/Q-type), is also expressed and contributes functionally to contraction of renal blood vessels in both mice and humans. Furthermore, preglomerular vascular SMCs and aortic SMCs coexpress L-, P-, and Q-type calcium channels within the same cell. Calcium channel blockers...... are widely used as pharmacological treatments. However, calcium channel antagonists vary in their selectivity for the various calcium channel subtypes, and the functional contribution from P/Q-type channels as compared with L-type should be considered. Confirming the presence of P/Q-type voltage...

  14. Ghrelin improves vascular autophagy in rats with vascular calcification.

    Science.gov (United States)

    Xu, Mingming; Liu, Lin; Song, Chenfang; Chen, Wei; Gui, Shuyan

    2017-06-15

    This study aimed to investigate whether ghrelin ameliorated vascular calcification (VC) through improving autophagy. VC model was induced by nicotine plus vitamin D 3 in rats and β-glycerophosphate in vascular smooth muscle cell (VSMC). Calcium deposition was detected by von Kossa staining or alizarin red S staining. ALP activity was also detected. Western blot was used to assess the protein expression. Ghrelin treatment attenuated the elevation of calcium deposition and ALP activity in VC model both in vivo and in vitro. Interesting, the protein levels of autophagy markers, LC3 and beclin1 were significantly upregulated by ghrelin in VC model. An autophagy inhibitor, 3-methyladenine blocks the ameliorative effect of ghrelin on VC. Furthermore, protein expressions of phosphate-AMPK were increased by ghrelin treatment both in calcified aorta and VSMC. The effect of ghrelin on autophagy induction and VC attenuation was prevented by AMPK inhibitor, compound C. Our results suggested that ghrelin improved autophagy through AMPK activation, which was resulted in VC amelioration. These data maybe throw light on prevention and therapy of VC. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Vascular lesions following radiation

    International Nuclear Information System (INIS)

    Fajardo, L.F.; Berthrong, M.

    1988-01-01

    The special radiation sensitivity of the vascular system is mainly linked to that of endothelial cells, which are perhaps the most radiation-vulnerable elements of mesenchymal tissues. Within the vascular tree, radiation injures most often capillaries, sinusoids, and small arteries, in that order. Lesions of veins are observed less often, but in certain tissues the veins are regularly damaged (e.g., intestine) or are the most affected structures (i.e., liver). Large arteries do suffer the least; however, when significant damage does occur in an elastic artery (e.g., thrombosis or rupture), it tends to be clinically significant and even fatal. Although not always demonstrable in human tissues, radiation vasculopathy generally is dose and time dependent. Like other radiation-induced lesions, the morphology in the vessels is not specific, but it is characteristic enough to be often recognizable. Vascular injury, especially by therapeutic radiation is not just a morphologic marker. It is a mediator of tissue damage; perhaps the most consistent pathogenetic mechanism in delayed radiation injury

  16. Vascular lumen formation.

    Science.gov (United States)

    Lammert, Eckhard; Axnick, Jennifer

    2012-04-01

    The vascular system developed early in evolution. It is required in large multicellular organisms for the transport of nutrients, oxygen, and waste products to and from tissues. The vascular system is composed of hollow tubes, which have a high level of complexity in vertebrates. Vasculogenesis describes the de novo formation of blood vessels, e.g., aorta formation in vertebrate embryogenesis. In contrast, angiogenesis is the formation of blood vessels from preexisting ones, e.g., sprouting of intersomitic blood vessels from the aorta. Importantly, the lumen of all blood vessels in vertebrates is lined and formed by endothelial cells. In both vasculogenesis and angiogenesis, lumen formation takes place in a cord of endothelial cells. It involves a complex molecular mechanism composed of endothelial cell repulsion at the cell-cell contacts within the endothelial cell cords, junctional rearrangement, and endothelial cell shape change. As the vascular system also participates in the course of many diseases, such as cancer, stroke, and myocardial infarction, it is important to understand and make use of the molecular mechanisms of blood vessel formation to better understand and manipulate the pathomechanisms involved.

  17. Pulmonary vascular imaging

    International Nuclear Information System (INIS)

    Fedullo, P.F.; Shure, D.

    1987-01-01

    A wide range of pulmonary vascular imaging techniques are available for the diagnostic evaluation of patients with suspected pulmonary vascular disease. The characteristics of any ideal technique would include high sensitivity and specificity, safety, simplicity, and sequential applicability. To date, no single technique meets these ideal characteristics. Conventional pulmonary angiography remains the gold standard for the diagnosis of acute thromboembolic disease despite the introduction of newer techniques such as digital subtraction angiography and magnetic resonance imaging. Improved noninvasive lower extremity venous testing methods, particularly impedance plethysmography, and ventilation-perfusion scanning can play significant roles in the noninvasive diagnosis of acute pulmonary emboli when properly applied. Ventilation-perfusion scanning may also be useful as a screening test to differentiate possible primary pulmonary hypertension from chronic thromboembolic pulmonary hypertension. And, finally, angioscopy may be a useful adjunctive technique to detect chronic thromboembolic disease and determine operability. Optimal clinical decision-making, however, will continue to require the proper interpretation of adjunctive information obtained from the less-invasive techniques, applied with an understanding of the natural history of the various forms of pulmonary vascular disease and with a knowledge of the capabilities and shortcomings of the individual techniques

  18. Pathophysiology of Headaches with a Prominent Vascular Component

    Directory of Open Access Journals (Sweden)

    Juan A Pareja

    1996-01-01

    Full Text Available Vascular changes, whether preliminary or secondary, seem to accompany most headaches. The literature concerning pathophysiological mechanisms in headaches where vascular phenomena are a major, integral part, ie, migraine and cluster headache syndrome, is reviewed and the most common forms of headache associated with cerebrovascular disease are discussed. Emphasis is placed on the vascular phenomena and on the abundant hypotheses and theories regarding headache mechanisms. This review also presents alternative explanatory models, and compares the available anatomical, physiological and biochemical results.

  19. Lymphangioma circumscriptum, angiokeratoma, or superficial vascular ectasia with epithelial hyperplasia?

    Science.gov (United States)

    Katsoulas, Nikolaos; Tosios, Konstantinos I; Argyris, Prokopios; Koutlas, Ioannis G; Sklavounou, Alexandra

    2014-08-01

    We report a case of lymphangioma circumscriptum (cavernous lymphangioma with epithelial hyperplasia) in a 12-year-old girl, presenting as a papillary tumor on the right dorsal side of her tongue. Microscopic examination found cavernous vascular channels lined by a single layer of CD31(+), podoplanin-positive, CD34(-) endothelial cells that occupied the papillary lamina propria and were accompanied by epithelial hyperplasia. A review of the literature on oral vascular tumors with epithelial hyperplasia, namely, lymphangioma circumscriptum and angiokeratoma, provided information that draws into question the use of these terms. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Channel Identification Machines

    Directory of Open Access Journals (Sweden)

    Aurel A. Lazar

    2012-01-01

    Full Text Available We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

  1. Channel identification machines.

    Science.gov (United States)

    Lazar, Aurel A; Slutskiy, Yevgeniy B

    2012-01-01

    We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s) onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS) with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

  2. Congenital vascular malformations in scintigraphic evaluation

    International Nuclear Information System (INIS)

    Pilecki, Stanisław; Gierach, Marcin; Gierach, Joanna; Świętaszczyk, Cyprian; Junik, Roman; Lasek, Władysław

    2014-01-01

    Congenital vascular malformations are tumour-like, non-neoplastic lesions caused by disorders of vascular tissue morphogenesis. They are characterised by a normal cell replacement cycle throughout all growth phases and do not undergo spontaneous involution. Here we present a scintigraphic image of familial congenital vascular malformations in two sisters. A 17-years-old young woman with a history of multiple hospitalisations for foci of vascular anomalies appearing progressively in the upper and lower right limbs, chest wall and spleen. A Parkes Weber syndrome was diagnosed based on the clinical picture. Due to the occurrence of new foci of malformations, a whole-body scintigraphic examination was performed. A 12-years-old girl reported a lump in the right lower limb present for approximately 2 years, which was clinically identified as a vascular lesion in the area of calcaneus and talus. Phleboscintigraphy visualized normal radiomarker outflow from the feet via the deep venous system, also observed in the superficial venous system once the tourniquets were released. In static and whole-body examinations vascular malformations were visualised in the area of the medial cuneiform, navicular and talus bones of the left foot, as well as in the projection of right calcaneus and above the right talocrural joint. People with undiagnosed disorders related to the presence of vascular malformations should undergo periodic follow-up to identify lesions that may be the cause of potentially serious complications and to assess the results of treatment. Presented scintigraphic methods may be used for both diagnosing and monitoring of disease progression

  3. Structural and functional imaging for vascular targeted photodynamic therapy

    Science.gov (United States)

    Li, Buhong; Gu, Ying; Wilson, Brian C.

    2017-02-01

    Vascular targeted photodynamic therapy (V-PDT) has been widely used for the prevention or treatment of vascular-related diseases, such as localized prostate cancer, wet age-related macular degeneration, port wine stains, esophageal varices and bleeding gastrointestinal mucosal lesions. In this study, the fundamental mechanisms of vascular responses during and after V-PDT will be introduced. Based on the V-PDT treatment of blood vessels in dorsal skinfold window chamber model, the structural and functional imaging, which including white light microscopy, laser speckle imaging, singlet oxygen luminescence imaging, and fluorescence imaging for evaluating vascular damage will be presented, respectively. The results indicate that vessel constriction and blood flow dynamics could be considered as the crucial biomarkers for quantitative evaluation of vascular damage. In addition, future perspectives of non-invasive optical imaging for evaluating vascular damage of V-PDT will be discussed.

  4. Upgrading a marketing channels role

    Directory of Open Access Journals (Sweden)

    Tišma-Borota Ankica

    2002-01-01

    Full Text Available As one of the marketing mix instruments, marketing channels were usually behind other instruments (product, price and promotion. Many companies regarded marketing channels as something that was 'left' after more important strategies of price, product and promotion were created. In recent past, things have changed and marketing channels became more interesting for research. This change came as a result of change in global market functioning especially in competitive advantage, distributors' strength and increasing technology.

  5. Channelling and electromagnetic radiation of channelling particles

    International Nuclear Information System (INIS)

    Kalashnikov, N.

    1983-01-01

    A brief description is presented of the channelling of charged particles between atoms in the crystal lattice. The specificities are discussed of the transverse motion of channelling particles as are the origin and properties of quasi-characteristic radiation of channelling particles which accompany transfers from one band of permissible energies of the transverse motion of channelling particles to the other. (B.S.)

  6. Arteriographic evaluation, in the perispheric vascular trauma

    International Nuclear Information System (INIS)

    Patino, Jairo Hernando; Granados, Ana Maria; Lopera B, Jorge; Prada W, Angela Maria

    1993-01-01

    136 patients were angiographically studied under the suspicion of perispheric vascular lesion submitted to the radiology department of the San Vicente de Paul University Hospital (H.U.S.VP.) Medellin Colombia. The majority of the patients were young with wounds caused by gunshots (79.4%). the must frequent angiographic indication was the proximity of the wound to a vascular path (44.5%). 63% of the patients with angiography indicative of abnormality needed surgery from which 21% were because of the proximity of the wound to a vascular path and 76% because of the mayor findings when admitted to the hospital. the possible complications as a result of the angiographic procedure were revised only find inc two mayor reactions to the contrast media. there were no late complications. Angiography is highlighting sensitive (100%) specific (98.5%) and secure in the evaluation of patients with perispheric vascular trauma. Due to the high number of false negatives when the physical examination is performed, every patient with a wound near a vascular path must be evaluated angiographically

  7. Fuel channel refilling

    International Nuclear Information System (INIS)

    Shoukri, M.; Abdul-Razzak, A.

    1992-11-01

    This report extends the work reported in document INFO-0370 on fuel channel refilling by providing analysis of the refilling tests conducted using the RD-14 and RD-14M test facilities. The analysis focuses on the general thermal-hydraulic characteristics of the facilities following various small and large inlet and outlet header breaks with emergency coolant injection. The two-fluid model thermal-hydraulic computer code CATHENA was tested against results obtained from selected experiments carried out in the two facilities. Conclusions related to the effect of break size, mode of emergency core injection, primary pump operation and parallel channels are presented. (Author) (116 figs., 17 tabs., 53 refs.)

  8. Fuel channel refilling

    International Nuclear Information System (INIS)

    Shoukri, M.; Abdul-Razzak, A.

    1990-04-01

    Analysis of existing data on fuel channel refilling is presented. The analysis focuses on the data obtained using the Stern Laboratories Cold Water Injection Test (CWIT) Facility. The two-fluid model thermal-hydraulics computer code CATHENA is also used to simulate experimental results on fuel channel refilling from both the CWIT and RD-14 facilities. Conclusions related to single and double break tests, including the effect of non-condensible gases, are presented. A set of recommendations is given for further analysis and separate effect experiments. (67 figs., 5 tabs., 24 refs.)

  9. Cryogenic microwave channelized receiver

    International Nuclear Information System (INIS)

    Rauscher, C.; Pond, J.M.; Tait, G.B.

    1996-01-01

    The channelized receiver being presented demonstrates the use of high temperature superconductor technology in a microwave system setting where superconductor, microwave-monolithic-integrated-circuit, and hybrid-integrated-circuit components are united in one package and cooled to liquid-nitrogen temperatures. The receiver consists of a superconducting X-band four-channel demultiplexer with 100-MHz-wide channels, four commercial monolithically integrated mixers, and four custom-designed hybrid-circuit detectors containing heterostructure ramp diodes. The composite receiver unit has been integrated into the payload of the second-phase NRL high temperature superconductor space experiment (HTSSE-II). Prior to payload assembly, the response characteristics of the receiver were measured as functions of frequency, temperature, and drive levels. The article describes the circuitry, discusses the key issues related to design and implementation, and summarizes the experimental results

  10. CIRSE Vascular Closure Device Registry

    International Nuclear Information System (INIS)

    Reekers, Jim A.; Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

    2011-01-01

    Purpose: Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods: The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results: Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0–14.5] for antegrade access and 1.8% (95% CI 1.1–2.9) for retrograde access (P = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only 5.9 cm, and two vessel occlusions. Conclusion: The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters.

  11. Neuroradiological findings in vascular dementia

    Energy Technology Data Exchange (ETDEWEB)

    Guermazi, Ali; Miaux, Yves; Suhy, Joyce; Pauls, Jon; Lopez, Ria [Synarc, Inc., Department of Radiology Services, San Francisco, CA (United States); Rovira-Canellas, Alex [Hospital General Universitari Vall d' Hebron, Unita de Resonancia Magnetica, Barcelona (Spain); Posner, Holly [Eisai, Inc., Teaneck, NJ (United States)

    2007-01-15

    There are multiple diagnostic criteria for vascular dementia (VaD) that may define different populations. Utilizing the criteria of the National Institute of Neurological Disorders and Stroke and Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) has provided improved consistency in the diagnosis of VaD. The criteria include a table listing brain imaging lesions associated with VaD. The different neuroradiological aspects of the criteria are reviewed based on the imaging data from an ongoing large-scale clinical trial testing a new treatment for VaD. The NINDS-AIREN criteria were applied by a centralized imaging rater to determine eligibility for enrollment in 1,202 patients using brain CT or MRI. Based on the above data set, the neuroradiological features that are associated with VaD and that can result from cerebral small-vessel disease with extensive leukoencephalopathy or lacunae (basal ganglia or frontal white matter), or may be the consequence of single strategically located infarcts or multiple infarcts in large-vessel territories, are illustrated. These features may also be the consequence of global cerebral hypoperfusion, intracerebral hemorrhage, or other mechanisms such as genetically determined arteriopathies. Neuroimaging confirmation of cerebrovascular disease in VaD provides information about the topography and severity of vascular lesions. Neuroimaging may also assist with the differential diagnosis of dementia associated with normal pressure hydrocephalus, chronic subdural hematoma, arteriovenous malformation or tumoral diseases. (orig.)

  12. CIRSE Vascular Closure Device Registry

    Science.gov (United States)

    Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

    2010-01-01

    Purpose Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0–14.5] for antegrade access and 1.8% (95% CI 1.1–2.9) for retrograde access (P = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only 5.9 cm, and two vessel occlusions. Conclusion The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters. PMID:20981425

  13. Vascular remodeling and mineralocorticoids.

    Science.gov (United States)

    Weber, K T; Sun, Y; Campbell, S E; Slight, S H; Ganjam, V K

    1995-01-01

    Circulating mineralocorticoid hormones are so named because of their important homeostatic properties that regulate salt and water balance via their action on epithelial cells. A broader range of functions in nonclassic target cellular sites has been proposed for these steroids and includes their contribution to wound healing following injury. A chronic, inappropriate (relative to intravascular volume and dietary sodium intake) elevation of these circulating hormones evokes a wound healing response in the absence of tissue injury--a wound healing response gone awry. The adverse remodeling of vascularized tissues seen in association with chronic mineralocorticoid excess is the focus of this review.

  14. Channel Modeling

    Science.gov (United States)

    Schmitz, Arne; Schinnenburg, Marc; Gross, James; Aguiar, Ana

    For any communication system the Signal-to-Interference-plus-Noise-Ratio of the link is a fundamental metric. Recall (cf. Chapter 9) that the SINR is defined as the ratio between the received power of the signal of interest and the sum of all "disturbing" power sources (i.e. interference and noise). From information theory it is known that a higher SINR increases the maximum possible error-free transmission rate (referred to as Shannon capacity [417] of any communication system and vice versa). Conversely, the higher the SINR, the lower will be the bit error rate in practical systems. While one aspect of the SINR is the sum of all distracting power sources, another issue is the received power. This depends on the transmitted power, the used antennas, possibly on signal processing techniques and ultimately on the channel gain between transmitter and receiver.

  15. A Microfluidic Approach for Studying Piezo Channels.

    Science.gov (United States)

    Maneshi, M M; Gottlieb, P A; Hua, S Z

    2017-01-01

    Microfluidics is an interdisciplinary field intersecting many areas in engineering. Utilizing a combination of physics, chemistry, biology, and biotechnology, along with practical applications for designing devices that use low volumes of fluids to achieve high-throughput screening, is a major goal in microfluidics. Microfluidic approaches allow the study of cells growth and differentiation using a variety of conditions including control of fluid flow that generates shear stress. Recently, Piezo1 channels were shown to respond to fluid shear stress and are crucial for vascular development. This channel is ideal for studying fluid shear stress applied to cells using microfluidic devices. We have developed an approach that allows us to analyze the role of Piezo channels on any given cell and serves as a high-throughput screen for drug discovery. We show that this approach can provide detailed information about the inhibitors of Piezo channels. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Vascular training and endovascular practice in Europe

    DEFF Research Database (Denmark)

    Liapis, C.D.; Avgerinos, E.D.; Sillesen, H.

    2009-01-01

    specialties was distributed to a VS educator within 14 European countries. European Vascular and Endovascular Monitor (EVEM) data also were processed to correlate endovascular practice with training models. RESULTS: Fourteen questionnaires were gathered. Vascular training in Europe appears in 3 models: 1....... Mono-specialty (independence): 7 countries, 2. Subspecialty: 5 countries, 3. An existing specialty within general surgery: 2 countries. Independent compared to non-independent certification shortens overall training length (5.9 vs 7.9 years, p=0.006), while increasing overall training devoted......% respectively. Countries with independent vascular certification, despite their lower average endovascular index (procedures per 100,000 population), reported a higher growth rate of aortic endovascular procedures (VS independent 132% vs VS non-independent 87%), within a four-year period (2003-2007). Peripheral...

  17. Intraoperative digital angiography: Peripheral vascular applications

    International Nuclear Information System (INIS)

    Bell, K.; Reifsteck, J.E.; Binet, E.F.; Fleisher, H.J.

    1986-01-01

    Intraoperative digital angiography is the procedure of choice for the peripheral vascular surgeon who wishes to evaluate his results before terminating anesthesia. Two operating suites at the John L. McClellan Memorial Veterans Hospital are equipped with permanent ceiling-mounted Philips C-arm fluoroscopes and share an ADAC 4100 digital angiographic system. In the last 18 months, 40 peripheral vascular intraoperative digital angiographic procedures have been performed, in all but two cases using direct arterial puncture. In 65% of cases, the intraoperative study showed no significant abnormality. In 12.5%, minor abnormalities not requiring reoperation were seen. In 22.5% of cases, the intraoperative digital angiogram revealed a significant abnormality requiring immediate operative revision. None of the patients who underwent reoperation experienced postoperative sequelae. Intraoperative digital angiography is useful in identifying complications of peripheral vascular operations

  18. Development of a Two-Channel Simultaneous Photoplethysmography Recording System

    Directory of Open Access Journals (Sweden)

    Kim Soon Chong

    2013-09-01

    Full Text Available Multi-site photoplethysmograph  (PPG recording enables researchers to study the vascular and hemodynamic  properties of human subjects. Currently, there  is  no  commercial  system  available  in  the  market  to  perform  either  one channel or multi-channel PPG recording. PPG is an optoelectronic technique that measures  changes  in  blood  volume  associated  with  cardiac  contraction.  The measurements  can  be  obtained  from  fingertips,  ear  lobes  and toes  due  to  their low absorption and high degree of vasculature. The main objective of this project is to develop a two-channel simultaneous PPG recording system to acquire PPG signals  from  two  different  physiological  sites  using  a  Nellcor  equivalent  PPG probe.  MATLAB  software  was  used  during  the  development  phase  to  ensure rapid prototyping. The experiment results show that there was no inter -channel delay in the developed two-channel PPG system. Our preliminary results show that the delays between the left and the right arm were from 4 to 12 ms in three healthy random subjects. The system is portable, powered by universal serial bus (USB and allows the user to do the PPG data acquisition in a clinical setting.

  19. Management of vascular anomalies: Review of institutional management algorithm

    Directory of Open Access Journals (Sweden)

    Lalit K Makhija

    2017-01-01

    Full Text Available Introduction: Vascular anomalies are congenital lesions broadly categorised into vascular tumour (haemangiomas and vascular dysmorphogenesis (vascular malformation. The management of these difficult problems has lately been simplified by the biological classification and multidisciplinary approach. To standardise the treatment protocol, an algorithm has been devised. The study aims to validate the algorithm in terms of its utility and presents our experience in managing vascular anomalies. Materials and Methods: The biological classification of Mulliken and Glowacki was followed. A detailed algorithm for management of vascular anomalies has been devised in the department. The protocol is being practiced by us since the past two decades. The data regarding the types of lesions and treatment modality used were maintained. Results and Conclusion: This study was conducted from 2002 to 2012. A total of 784 cases of vascular anomalies were included in the study of which 196 were haemangiomas and 588 were vascular malformations. The algorithmic approach has brought an element of much-needed objectivity in the management of vascular anomalies. This has helped us to define the management of particular lesion considering its pathology, extent and aesthetic and functional consequences of ablation to a certain extent.

  20. Evaluating Peripheral Vascular Injuries: Is Color Doppler Enough for Diagnosis?

    Directory of Open Access Journals (Sweden)

    Mohd Lateef Wani

    2014-03-01

    Full Text Available Background:: Vascular injury poses a serious threat to limb and life. Thus, diagnosis should be made immediately with minimally invasive methods. Doppler is a good aid in diagnosis of vascular injury. Methods:: The present prospective study was conducted on 150 patients who presented with soft signs (the signs which are suggestive but not confirmatory of vascular injury. They were subjected to color Doppler examination before exploration. The patients with the features of vascular injury on color Doppler were subjected to exploration. On the other hand, those who had normal Doppler were subjected to CT- angiography. Then, the findings of the exploration were matched with those of color Doppler. The data were analyzed using the SPSS statistical software. Results:: Out of the 150 Doppler examinations, 110 (73.33% were reported as positive, while 40 were reported as negative for vascular injury. These were subjected to CT-angiography and seven of them had the features of vascular injury on CT-angiography. All the patients with positive Doppler or CT angiography findings were subjected to exploration. Doppler had a sensitivity of 94% and specificity of 82.5% in diagnosis of vascular injury using Binary classification test. Conclusions:: Color Doppler is an easily available, reliable, and handy method of diagnosing a vascular injury. It has a very high sensitivity and specificity in diagnosis of vascular injuries.

  1. Early vascular plants in the Czech Republic

    OpenAIRE

    Uhlířová, Monika

    2017-01-01

    Vascular plants are characterized as a group of plants, which are already fully adapted to live on the land. Their evolution is a result of a set of adaptations that have required the necessary changes at anatomical and morphological level. Some evidences about the rise of vascular plants appear in the fossil record from the Middle Ordovician in the form of spores and later also from the Early Silurian in the form of megafossils. The aim of the thesis is to briefly describe and discuss the mo...

  2. Pacinian channel mediated vasoconstriction in the fingers during vibration exposure

    OpenAIRE

    Ye, Ying

    2013-01-01

    A review of the literature showed that acute vascular responses to hand-transmitted vibration depend on the magnitude, the frequency, and the duration of the vibration but the mechanisms involved in the immediate vasoconstriction on exposure to vibration are not clear. This research was designed to advance understanding of the relation between the characteristics of vibration and changes in vascular circulation on exposed hands, and to develop a model of the mechanoreceptor channel involved i...

  3. Interventional vascular radiology

    International Nuclear Information System (INIS)

    Yune, H.Y.

    1984-01-01

    The papers published during this past year in the area of interventional vascular radiology presented some useful modifications and further experiences both in the area of thromboembolic therapy and in dilation and thrombolysis, but no new techniques. As an introductory subject, an excellent monograph reviewing the current spectrum of pharmacoangiography was presented in Radiographics. Although the presented material is primarily in diagnostic application of various pharmacologic agents used today to facilitate demonstration of certain diagnostic criteria of various disease processes, both vasodilatory and vasoconstrictive reaction to these agents are widely used in various therapeutic vascular procedures. This monograph should be reviewed by every angiographer whether or not he or she performs interventional procedures, and it would be very convenient to have this table available in the angiography suite. In a related subject, Bookstein and co-workers have written an excellent review concerning pharmacologic manipulations of various blood coagulative parameters during angiography. Understanding the proper method of manipulation of the bloodclotting factors during angiography, and especially during interventional angiography, is extremely important. Particularly, the method of manipulating the coagulation with the use of heparin and protamine and modification of the platelet activity by using aspirin and dipyridamole are succinctly reviewed. The systemic and selective thrombolytic activities of streptokianse are also discussed

  4. Risk and timing of clinical events according to diabetic status of patients treated with everolimus-eluting bioresorbable vascular scaffolds versus everolimus-eluting stent: 2-year results from a propensity score matched comparison of ABSORB EXTEND and SPIRIT trials.

    Science.gov (United States)

    Campos, Carlos M; Caixeta, Adriano; Franken, Marcelo; Bartorelli, Antonio L; Whitbourn, Robert J; Wu, Chiung-Jen; Li Paul Kao, Hsien; Rosli, Mohd Ali; Carrie, Didier; De Bruyne, Bernard; Stone, Gregg W; Serruys, Patrick W; Abizaid, Alexandre

    2018-02-15

    to compare the occurrence of clinical events in diabetics treated with the Absorb bioresorbable vascular scaffold (Absorb BVS; Abbott Vascular, Santa Clara, CA) versus everolimus-eluting metal stents (EES; XIENCE V; Abbott Vascular, Santa Clara, CA) BACKGROUND: There are limited data dedicated to clinical outcomes of diabetic patients treated with bioresorbable scaffolds (BRS) at 2-year horizon. The present study included 812 patients in the ABSORB EXTEND study in which a total of 215 diabetic patients were treated with Absorb BVS. In addition, 882 diabetic patients treated with EES in pooled data from the SPIRIT clinical program (SPIRIT II, SPIRIT III and SPIRIT IV trials) were used for comparison by applying propensity score matching using 29 different variables. The primary endpoint was ischemia driven major adverse cardiac events (ID-MACE), including cardiac death, myocardial infarction (MI), and ischemia driven target lesion revascularization (ID-TLR). After 2 years, the ID-MACE rate was 6.5% in the Absorb BVS vs. 8.9% in the Xience group (P = 0.40). There was no difference for MACE components or definite/probable device thrombosis (HR: 1.43 [0.24,8.58]; P = 0.69). The occurrence of MACE was not different for both diabetic status (insulin- and non-insulin-requiring diabetes) in all time points up to the 2-year follow-up for the Absorb and Xience groups. In this largest ever patient-level pooled comparison on the treatment of diabetic patients with BRS out to two years, individuals with diabetes treated with the Absorb BVS had a similar rate of MACE as compared with diabetics treated with the Xience EES. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Vascular Remodeling in Experimental Hypertension

    Directory of Open Access Journals (Sweden)

    Norma R. Risler

    2005-01-01

    Full Text Available The basic hemodynamic abnormality in hypertension is an increased peripheral resistance that is due mainly to a decreased vascular lumen derived from structural changes in the small arteries wall, named (as a whole vascular remodeling. The vascular wall is an active, flexible, and integrated organ made up of cellular (endothelial cells, smooth muscle cells, adventitia cells, and fibroblasts and noncellular (extracellular matrix components, which in a dynamic way change shape or number, or reorganize in response to physiological and pathological stimuli, maintaining the integrity of the vessel wall in physiological conditions or participating in the vascular changes in cardiovascular diseases such as hypertension. Research focused on new signaling pathways and molecules that can participate in the mechanisms of vascular remodeling has provided evidence showing that vascular structure is not only affected by blood pressure, but also by mechanisms that are independent of the increased pressure. This review will provide an overview of the evidence, explaining some of the pathophysiologic mechanisms participating in the development of the vascular remodeling, in experimental models of hypertension, with special reference to the findings in spontaneously hypertensive rats as a model of essential hypertension, and in fructose-fed rats as a model of secondary hypertension, in the context of the metabolic syndrome. The understanding of the mechanisms producing the vascular alterations will allow the development of novel pharmacological tools for vascular protection in hypertensive disease.

  6. Vascular pattern formation in plants.

    Science.gov (United States)

    Scarpella, Enrico; Helariutta, Ykä

    2010-01-01

    Reticulate tissue systems exist in most multicellular organisms, and the principles underlying the formation of cellular networks have fascinated philosophers, mathematicians, and biologists for centuries. In particular, the beautiful and varied arrangements of vascular tissues in plants have intrigued mankind since antiquity, yet the organizing signals have remained elusive. Plant vascular tissues form systems of interconnected cell files throughout the plant body. Vascular cells are aligned with one another along continuous lines, and vascular tissues differentiate at reproducible positions within organ environments. However, neither the precise path of vascular differentiation nor the exact geometry of vascular networks is fixed or immutable. Several recent advances converge to reconcile the seemingly conflicting predictability and plasticity of vascular tissue patterns. A control mechanism in which an apical-basal flow of signal establishes a basic coordinate system for body axis formation and vascular strand differentiation, and in which a superimposed level of radial organizing cues elaborates cell patterns, would generate a reproducible tissue configuration in the context of an underlying robust, self-organizing structure, and account for the simultaneous regularity and flexibility of vascular tissue patterns. Copyright 2010 Elsevier Inc. All rights reserved.

  7. B vitamins influence vascular cognitive impairment

    Science.gov (United States)

    As the number of elderly in the USA and globally continues to increase, age-related neurological disorders, such as Alzheimer's disease and vascular dementia, are a growing concern. The loss of memory, emotional changes, and impairments in general cognitive functioning frequently result in social is...

  8. Identifying developmental vascular disruptor compounds using a predictive signature and alternative toxicity models

    Science.gov (United States)

    Identifying Developmental Vascular Disruptor Compounds Using a Predictive Signature and Alternative Toxicity Models Presenting Author: Tamara Tal Affiliation: U.S. EPA/ORD/ISTD, RTP, NC, USA Chemically induced vascular toxicity during embryonic development can result in a wide...

  9. Additive Manufacturing of Vascular Grafts and Vascularized Tissue Constructs.

    Science.gov (United States)

    Elomaa, Laura; Yang, Yunzhi Peter

    2017-10-01

    There is a great need for engineered vascular grafts among patients with cardiovascular diseases who are in need of bypass therapy and lack autologous healthy blood vessels. In addition, because of the severe worldwide shortage of organ donors, there is an increasing need for engineered vascularized tissue constructs as an alternative to organ transplants. Additive manufacturing (AM) offers great advantages and flexibility of fabrication of cell-laden, multimaterial, and anatomically shaped vascular grafts and vascularized tissue constructs. Various inkjet-, extrusion-, and photocrosslinking-based AM techniques have been applied to the fabrication of both self-standing vascular grafts and porous, vascularized tissue constructs. This review discusses the state-of-the-art research on the use of AM for vascular applications and the key criteria for biomaterials in the AM of both acellular and cellular constructs. We envision that new smart printing materials that can adapt to their environment and encourage rapid endothelialization and remodeling will be the key factor in the future for the successful AM of personalized and dynamic vascular tissue applications.

  10. Vascularized bone transplant chimerism mediated by vascular endothelial growth factor.

    Science.gov (United States)

    Willems, Wouter F; Larsen, Mikko; Friedrich, Patricia F; Bishop, Allen T

    2015-01-01

    Vascular endothelial growth factor (VEGF) induces angiogenesis and osteogenesis in bone allotransplants. We aim to determine whether bone remodeling in VEGF-treated bone allotransplants results from repopulation with circulation-derived autogenous cells or survival of allogenic transplant-derived cells. Vascularized femoral bone transplants were transplanted from female Dark Agouti rats (DA;RT1(a) ) to male Piebald Viral Glaxo (PVG;RT1(c) ). Arteriovenous bundle implantation and short-term immunosuppression were used to maintain cellular viability. VEGF was encapsulated in biodegradable microspheres and delivered intramedullary in the experimental group (n = 22). In the control group (n = 22), no VEGF was delivered. Rats were sacrificed at 4 or 18 weeks. Laser capture microdissection of bone remodeling areas was performed at the inner and outer cortex. Sex-mismatched genes were quantified with reverse transcription-polymerase chain reaction to determine the amount of male cells to total cells, defined as the relative expression ratio (rER). At 4 weeks, rER was significantly higher at the inner cortex in VEGF-treated transplants as compared to untreated transplants (0.622 ± 0.225 vs. 0.362 ± 0.081, P = 0.043). At 4 weeks, the outer cortex in the control group had a significantly higher rER (P = 0.038), whereas in the VEGF group, the inner cortex had a higher rER (P = 0.015). Over time, in the outer cortex the rER significantly increased to 0.634 ± 0.106 at 18 weeks in VEGF-treated rats (P = 0.049). At 18 weeks, the rER was >0.5 at all cortical areas in both groups. These in vivo findings suggest a chemotactic effect of intramedullary applied VEGF on recipient-derived bone and could imply that more rapid angiogenesis of vascularized allotransplants can be established with microencapsulated VEGF. © 2014 Wiley Periodicals, Inc.

  11. The pathology and pathophysiology of vascular dementia.

    Science.gov (United States)

    Kalaria, Raj N

    2017-12-19

    Vascular dementia (VaD) is widely recognised as the second most common type of dementia. Consensus and accurate diagnosis of clinically suspected VaD relies on wide-ranging clinical, neuropsychological and neuroimaging measures in life but more importantly pathological confirmation. Factors defining subtypes of VaD include the nature and extent of vascular pathologies, degree of involvement of extra and intracranial vessels and the anatomical location of tissue changes as well as time after the initial vascular event. Atherosclerotic and cardioembolic diseases combined appear the most common subtypes of vascular brain injury. In recent years, cerebral small vessel disease (SVD) has gained prominence worldwide as an important substrate of cognitive impairment. SVD is characterised by arteriolosclerosis, lacunar infarcts and cortical and subcortical microinfarcts and diffuse white matter changes, which involve myelin loss and axonal abnormalities. Global brain atrophy and focal degeneration of the cerebrum including medial temporal lobe atrophy are also features of VaD similar to Alzheimer's disease. Hereditary arteriopathies have provided insights into the mechanisms of dementia particularly how arteriolosclerosis, a major contributor of SVD promotes cognitive impairment. Recently developed and validated neuropathology guidelines indicated that the best predictors of vascular cognitive impairment were small or lacunar infarcts, microinfarcts, perivascular space dilation, myelin loss, arteriolosclerosis and leptomeningeal cerebral amyloid angiopathy. While these substrates do not suggest high specificity, VaD is likely defined by key neuronal and dendro-synaptic changes resulting in executive dysfunction and related cognitive deficits. Greater understanding of the molecular pathology is needed to clearly define microvascular disease and vascular substrates of dementia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effects of river restoration on riparian biodiversity in secondary channels of the Pite River, Sweden.

    Science.gov (United States)

    Helfield, James M; Engström, Johanna; Michel, James T; Nilsson, Christer; Jansson, Roland

    2012-01-01

    Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers. In this study, we examined the effects of restoration on riparian plant communities at previously disconnected secondary channels of the Pite River. We detected no increase in riparian diversity at restored sites relative to unrestored (i.e., disconnected) sites, but we did observe significant differences in species composition of both vascular plant and bryophyte communities. Disconnected sites featured greater zonation, with mesic-hydric floodplain species represented in plots closest to the stream and mesic-xeric upland species represented in plots farthest from the stream. In contrast, restored sites were most strongly represented by upland species at all distances relative to the stream. These patterns likely result from the increased water levels in reconnected channels where, prior to restoration, upland plants had expanded toward the stream. Nonetheless, the restored fluvial regime has not brought about the development of characteristic flood-adapted plant communities, probably due to the short time interval (ca. 5 years) since restoration. Previous studies have demonstrated relatively quick responses to similar restoration in single-channel tributaries, but secondary channels may respond differently due to the more buffered hydrologic regimes typically seen in anabranching systems. These findings illustrate how restoration outcomes can vary according to hydrologic, climatic and ecological factors, reinforcing the need for site-specific restoration strategies.

  13. SIFlore, a dataset of geographical distribution of vascular plants covering five centuries of knowledge in France: Results of a collaborative project coordinated by the Federation of the National Botanical Conservatories.

    Science.gov (United States)

    Just, Anaïs; Gourvil, Johan; Millet, Jérôme; Boullet, Vincent; Milon, Thomas; Mandon, Isabelle; Dutrève, Bruno

    2015-01-01

    More than 20 years ago, the French Muséum National d'Histoire Naturelle (MNHN, Secretariat of the Fauna and Flora) published the first part of an atlas of the flora of France at a 20km spatial resolution, accounting for 645 taxa (Dupont 1990). Since then, at the national level, there has not been any work on this scale relating to flora distribution, despite the obvious need for a better understanding. In 2011, in response to this need, the Federation des Conservatoires Botaniques Nationaux (FCBN, http://www.fcbn.fr) launched an ambitious collaborative project involving eleven national botanical conservatories of France. The project aims to establish a formal procedure and standardized system for data hosting, aggregation and publication for four areas: flora, fungi, vegetation and habitats. In 2014, the first phase of the project led to the development of the national flora dataset: SIFlore. As it includes about 21 million records of flora occurrences, this is currently the most comprehensive dataset on the distribution of vascular plants (Tracheophyta) in the French territory. SIFlore contains information for about 15'454 plant taxa occurrences (indigenous and alien taxa) in metropolitan France and Reunion Island, from 1545 until 2014. The data records were originally collated from inventories, checklists, literature and herbarium records. SIFlore was developed by assembling flora datasets from the regional to the national level. At the regional level, source records are managed by the national botanical conservatories that are responsible for flora data collection and validation. In order to present our results, a geoportal was developed by the Fédération des conservatoires botaniques nationaux that allows the SIFlore dataset to be publically viewed. This portal is available at: http://siflore.fcbn.fr. As the FCBN belongs to the Information System for Nature and Landscapes' (SINP), a governmental program, the dataset is also accessible through the websites of

  14. Channelling of flow through fractures in rock

    International Nuclear Information System (INIS)

    Bourke, P.J.

    1987-05-01

    A method of mapping the channelling of flow in rock fractures formed by contacts between rock faces and of measuring the effective apertures of channels has been developed. Some typical results are given. (author)

  15. Cardiac and vascular malformations

    International Nuclear Information System (INIS)

    Ley, S.; Ley-Zaporozhan, J.

    2015-01-01

    Malformations of the heart and great vessels show a high degree of variation. There are numerous variants and defects with only few clinical manifestations and are only detected by chance, such as a persistent left superior vena cava or a partial anomalous pulmonary venous connection. Other cardiovascular malformations are manifested directly after birth and need prompt mostly surgical interventions. At this point in time echocardiography is the diagnostic modality of choice for morphological and functional characterization of malformations. Additional imaging using computed tomography (CT) or magnetic resonance imaging (MRI) is only required in a minority of cases. If so, the small anatomical structures, the physiological tachycardia and tachypnea are a challenge for imaging modalities and strategies. This review article presents the most frequent vascular, cardiac and complex cardiovascular malformations independent of the first line diagnostic imaging modality. (orig.) [de

  16. Macrophage migration inhibitory factor induces vascular leakage via autophagy

    Directory of Open Access Journals (Sweden)

    Hong-Ru Chen

    2015-01-01

    Full Text Available Vascular leakage is an important feature of acute inflammatory shock, which currently has no effective treatment. Macrophage migration inhibitory factor (MIF is a pro-inflammatory cytokine that can induce vascular leakage and plays an important role in the pathogenesis of shock. However, the mechanism of MIF-induced vascular leakage is still unclear. In this study, using recombinant MIF (rMIF, we demonstrated that MIF induced disorganization and degradation of junction proteins and increased the permeability of human endothelial cells in vitro. Western blotting analysis showed that rMIF treatment induced LC3 conversion and p62 degradation. Inhibition of autophagy with a PI3K inhibitor (3-MA, a ROS scavenger (NAC or autophagosomal-lysosomal fusion inhibitors (bafilomycin A1 and chloroquine rescued rMIF-induced vascular leakage, suggesting that autophagy mediates MIF-induced vascular leakage. The potential involvement of other signaling pathways was also studied using different inhibitors, and the results suggested that MIF-induced vascular leakage may occur through the ERK pathway. In conclusion, we showed that MIF triggered autophagic degradation of endothelial cells, resulting in vascular leakage. Inhibition of MIF-induced autophagy may provide therapeutic targets against vascular leakage in inflammatory shock.

  17. FPGA controlled artificial vascular system

    Directory of Open Access Journals (Sweden)

    Laqua D.

    2015-09-01

    Full Text Available Monitoring the oxygen saturation of an unborn child is an invasive procedure, so far. Transabdominal fetal pulse oximetry is a promising method under research, used to estimate the oxygen saturation of a fetus noninvasively. Due to the nature of the method, the fetal information needs to be extracted from a mixed signal. To properly evaluate signal processing algorithms, a phantom modeling fetal and maternal blood circuits and tissue layers is necessary. This paper presents an improved hardware concept for an artificial vascular system, utilizing an FPGA based CompactRIO System from National Instruments. The experimental model to simulate the maternal and fetal blood pressure curve consists of two identical hydraulic circuits. Each of these circuits consists of a pre-pressure system and an artificial vascular system. Pulse curves are generated by proportional valves, separating these two systems. The dilation of the fetal and maternal artificial vessels in tissue substitutes is measured by transmissive and reflective photoplethysmography. The measurement results from the pressure sensors and the transmissive optical sensors are visualized to show the functionality of the pulse generating systems. The trigger frequency for the maternal valve was set to 1 per second, the fetal valve was actuated at 0.7 per second for validation. The reflective curve, capturing pulsations of the fetal and maternal circuit, was obtained with a high power LED (905 nm as light source. The results show that the system generates pulse curves, similar to its physiological equivalent. Further, the acquired reflective optical signal is modulated by the alternating diameter of the tubes of both circuits, allowing for tests of signal processing algorithms.

  18. CIRSE Vascular Closure Device Registry

    NARCIS (Netherlands)

    Reekers, Jim A.; Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

    2011-01-01

    Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. The CIRSE registry of closure devices

  19. Dynamic adaption of vascular morphology

    DEFF Research Database (Denmark)

    Okkels, Fridolin; Jacobsen, Jens Christian Brings

    2012-01-01

    The structure of vascular networks adapts continuously to meet changes in demand of the surrounding tissue. Most of the known vascular adaptation mechanisms are based on local reactions to local stimuli such as pressure and flow, which in turn reflects influence from the surrounding tissue. Here ...

  20. Diagnostic criteria for vascular dementia

    NARCIS (Netherlands)

    Scheltens, P.; Hijdra, A. H.

    1998-01-01

    The term vascular dementia implies the presence of a clinical syndrome (dementia) caused by, or at least assumed to be caused by, a specific disorder (cerebrovascular disease). In this review, the various sets of criteria used to define vascular dementia are outlined. The various sets of criteria

  1. The vascular secret of Klotho

    DEFF Research Database (Denmark)

    Lewin, Ewa; Olgaard, Klaus

    2015-01-01

    Klotho is an evolutionarily highly conserved protein related to longevity. Increasing evidence of a vascular protecting effect of the Klotho protein has emerged and might be important for future treatments of uremic vascular calcification. It is still disputed whether Klotho is locally expressed ...

  2. Social media in vascular surgery.

    Science.gov (United States)

    Indes, Jeffrey E; Gates, Lindsay; Mitchell, Erica L; Muhs, Bart E

    2013-04-01

    There has been a tremendous growth in the use of social media to expand the visibility of various specialties in medicine. The purpose of this paper is to describe the latest updates on some current applications of social media in the practice of vascular surgery as well as existing limitations of use. This investigation demonstrates that the use of social networking sites appears to have a positive impact on vascular practice, as is evident through the incorporation of this technology at the Cleveland Clinic and by the Society for Vascular Surgery into their approach to patient care and physician communication. Overall, integration of social networking technology has current and future potential to be used to promote goals, patient awareness, recruitment for clinical trials, and professionalism within the specialty of vascular surgery. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  3. Impaired vascular function after exposure to diesel exhaust generated at urban transient running conditions

    Directory of Open Access Journals (Sweden)

    Westerholm Roger

    2010-07-01

    Full Text Available Abstract Background Traffic emissions including diesel engine exhaust are associated with increased respiratory and cardiovascular morbidity and mortality. Controlled human exposure studies have demonstrated impaired vascular function after inhalation of exhaust generated by a diesel engine under idling conditions. Objectives To assess the vascular and fibrinolytic effects of exposure to diesel exhaust generated during urban-cycle running conditions that mimic ambient 'real-world' exposures. Methods In a randomised double-blind crossover study, eighteen healthy male volunteers were exposed to diesel exhaust (approximately 250 μg/m3 or filtered air for one hour during intermittent exercise. Diesel exhaust was generated during the urban part of the standardized European Transient Cycle. Six hours post-exposure, vascular vasomotor and fibrinolytic function was assessed during venous occlusion plethysmography with intra-arterial agonist infusions. Measurements and Main Results Forearm blood flow increased in a dose-dependent manner with both endothelial-dependent (acetylcholine and bradykinin and endothelial-independent (sodium nitroprusside and verapamil vasodilators. Diesel exhaust exposure attenuated the vasodilatation to acetylcholine (P Conclusion Exposure to diesel exhaust generated under transient running conditions, as a relevant model of urban air pollution, impairs vasomotor function and endogenous fibrinolysis in a similar way as exposure to diesel exhaust generated at idling. This indicates that adverse vascular effects of diesel exhaust inhalation occur over different running conditions with varying exhaust composition and concentrations as well as physicochemical particle properties. Importantly, exposure to diesel exhaust under ETC conditions was also associated with a novel finding of impaired of calcium channel-dependent vasomotor function. This implies that certain cardiovascular endpoints seem to be related to general diesel

  4. Multi-channel software defined radio experimental evaluation and analysis

    CSIR Research Space (South Africa)

    Van der Merwe, JR

    2014-09-01

    Full Text Available Multi-channel software-defined radios (SDRs) can be utilised as inexpensive prototyping platforms for transceiver arrays. The application for multi-channel prototyping is discussed and measured results of coherent channels for both receiver...

  5. The roles of KCa, KATP, and KV channels in regulating cutaneous vasodilation and sweating during exercise in the heat.

    Science.gov (United States)

    Louie, Jeffrey C; Fujii, Naoto; Meade, Robert D; McNeely, Brendan D; Kenny, Glen P

    2017-05-01

    We recently showed the varying roles of Ca 2+ -activated (K Ca ), ATP-sensitive (K ATP ), and voltage-gated (K V ) K + channels in regulating cholinergic cutaneous vasodilation and sweating in normothermic conditions. However, it is unclear whether the respective contributions of these K + channels remain intact during dynamic exercise in the heat. Eleven young (23 ± 4 yr) men completed a 30-min exercise bout at a fixed rate of metabolic heat production (400 W) followed by a 40-min recovery period in the heat (35°C, 20% relative humidity). Cutaneous vascular conductance (CVC) and local sweat rate were assessed at four forearm skin sites perfused via intradermal microdialysis with: 1 ) lactated Ringer solution (control); 2 ) 50 mM tetraethylammonium (nonspecific K Ca channel blocker); 3 ) 5 mM glybenclamide (selective K ATP channel blocker); or 4 ) 10 mM 4-aminopyridine (nonspecific K V channel blocker). Responses were compared at baseline and at 10-min intervals during and following exercise. K Ca channel inhibition resulted in greater CVC versus control at end exercise ( P = 0.04) and 10 and 20 min into recovery (both P exercise (all P ≤ 0.04), and 10 min into recovery ( P = 0.02). No differences in CVC were observed with K V channel inhibition during baseline ( P = 0.15), exercise (all P ≥ 0.06), or recovery (all P ≥ 0.14). With the exception of K V channel inhibition augmenting sweating during baseline ( P = 0.04), responses were similar to control with all K + channel blockers during each time period (all P ≥ 0.07). We demonstrated that K Ca and K ATP channels contribute to the regulation of cutaneous vasodilation during rest and/or exercise and recovery in the heat. Copyright © 2017 the American Physiological Society.

  6. T cells in vascular inflammatory diseases

    Directory of Open Access Journals (Sweden)

    Lucas L Lintermans

    2014-10-01

    Full Text Available Inflammation of the human vasculature is a manifestation of many different diseases ranging from systemic autoimmune diseases to chronic inflammatory diseases, in which multiple types of immune cells are involved. For both autoimmune diseases and chronic inflammatory diseases several observations support a key role for T lymphocytes in these disease pathologies, but the underlying mechanisms are poorly understood. Previous studies in several autoimmune diseases have demonstrated a significant role for a specific subset of CD4+ T cells termed effector memory T cells. This expanded population of effector memory T cells may contribute to tissue injury and disease progression. These cells exert multiple pro-inflammatory functions through the release of effector cytokines. Many of these cytokines have been detected in the inflammatory lesions and participate in the vasculitic reaction, contributing to recruitment of macrophages, neutrophils, dendritic cells, NK cells, B cells and T cells. In addition, functional impairment of regulatory T cells paralyzes anti-inflammatory effects in vasculitic disorders. Interestingly, activation of effector memory T cells in uniquely dependent on the voltage-gated Kv1.3 potassium channel providing an anchor for specific drug targeting. In this review, we focus on the CD4+ T cells in the context of vascular inflammation and describe the evidence supporting the role of different T cell subsets in vascular inflammation. Selective targeting of pathogenic effector memory T cells might enable a more tailored therapeutic approach that avoids unwanted adverse side effects of generalized immunosuppression by modulating the effector functions of T cell responses to inhibit the development of vascular inflammation.

  7. Decreasing vortex flux in channels

    International Nuclear Information System (INIS)

    Migaj, V.K.; Nosova, I.S.

    1979-01-01

    A new method for reducing vortex flow losses in power plant channels is suggested. The method is based on vortex splitting in vortex flow areas with transverse barriers placed on the channel walls. The upper barrier ends are at the level of the upper boundary of the vortex area and don't protrude to the active flow beyond this boundary. The effectiveness of the method suggested is illustrated taking as an example the investigation of square and flat channels with abrupt widening in one plane, diffusers with widening in one plane, or a rectangualr bend. It is shown that splitting the vortex areas with transverse barriers in the channels results in reduction of hydraulic losses by 10-25%. The above method is characteristic of an extreme simplicity, its application doesn't require changes in the channel shape nor installation of any devices in the flow

  8. Double-filter identification of vascular-expressed genes using Arabidopsis plants with vascular hypertrophy and hypotrophy.

    Science.gov (United States)

    Ckurshumova, Wenzislava; Scarpella, Enrico; Goldstein, Rochelle S; Berleth, Thomas

    2011-08-01

    Genes expressed in vascular tissues have been identified by several strategies, usually with a focus on mature vascular cells. In this study, we explored the possibility of using two opposite types of altered tissue compositions in combination with a double-filter selection to identify genes with a high probability of vascular expression in early organ primordia. Specifically, we generated full-transcriptome microarray profiles of plants with (a) genetically strongly reduced and (b) pharmacologically vastly increased vascular tissues and identified a reproducible cohort of 158 transcripts that fulfilled the dual requirement of being underrepresented in (a) and overrepresented in (b). In order to assess the predictive value of our identification scheme for vascular gene expression, we determined the expression patterns of genes in two unbiased subsamples. First, we assessed the expression patterns of all twenty annotated transcription factor genes from the cohort of 158 genes and found that seventeen of the twenty genes were preferentially expressed in leaf vascular cells. Remarkably, fifteen of these seventeen vascular genes were clearly expressed already very early in leaf vein development. Twelve genes with published leaf expression patterns served as a second subsample to monitor the representation of vascular genes in our cohort. Of those twelve genes, eleven were preferentially expressed in leaf vascular tissues. Based on these results we propose that our compendium of 158 genes represents a sample that is highly enriched for genes expressed in vascular tissues and that our approach is particularly suited to detect genes expressed in vascular cell lineages at early stages of their inception. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Quantum communication under channel uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Noetzel, Janis Christian Gregor

    2012-09-06

    This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

  10. Vascular injuries after bear attacks: Incidence, surgical challenges and outcome.

    Science.gov (United States)

    Wani, Mohd Lateef; Ahangar, Abdul Gani; Lone, Gh Nabi; Lone, Reyaz Ahmad; Ashraf, Hakeem Zubair; Dar, Abdul Majeed; Bhat, M A; Singh, Shyam; Bijli, Akram Hussain; Irshad, Ifat

    2011-01-01

    Bear mauling is rarely reported in medical literature due to its rare occurrence. Present study was undertaken to describe the pattern and management of bear maul vascular injuries in Kashmir. Study of patients with bear maul vascular injury from 1(st) Jan 2004 to 31(st) Dec. 2008. Fifteen patients with bear maul vascular injury were studied. All patients of bear maul without vascular injury were excluded from the study. Most of the patients were treated by reverse saphenous vein graft or end to end anastomosis. Most common complication was wound infection (20%) followed by graft occlusion (13.33%). There was no operative death. Bear attacks are very common in Kashmir. Vascular injury due to bear maul needs prompt resuscitation and revascularization. Results are very good provided timely intervention for revascularization is done.

  11. Cartilage oligomeric matrix protein enhances the vascularization of acellular nerves

    Directory of Open Access Journals (Sweden)

    Wei-ling Cui

    2016-01-01

    Full Text Available Vascularization of acellular nerves has been shown to contribute to nerve bridging. In this study, we used a 10-mm sciatic nerve defect model in rats to determine whether cartilage oligomeric matrix protein enhances the vascularization of injured acellular nerves. The rat nerve defects were treated with acellular nerve grafting (control group alone or acellular nerve grafting combined with intraperitoneal injection of cartilage oligomeric matrix protein (experimental group. As shown through two-dimensional imaging, the vessels began to invade into the acellular nerve graft from both anastomotic ends at day 7 post-operation, and gradually covered the entire graft at day 21. The vascular density, vascular area, and the velocity of revascularization in the experimental group were all higher than those in the control group. These results indicate that cartilage oligomeric matrix protein enhances the vascularization of acellular nerves.

  12. Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells.

    Directory of Open Access Journals (Sweden)

    Yun-Yun Ma

    Full Text Available Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification.

  13. Improved vascularization of planar membrane diffusion devices following continuous infusion of vascular endothelial growth factor.

    Science.gov (United States)

    Trivedi, N; Steil, G M; Colton, C K; Bonner-Weir, S; Weir, G C

    2000-01-01

    Improving blood vessel formation around an immunobarrier device should improve the survival of the encapsulated tissue. In the present study we investigated the formation of new blood vessels around a planar membrane diffusion device (the Baxter Theracyte System) undergoing a continuous infusion of vascular endothelial growth factor through the membranes and into the surrounding tissue. Each device (20 microl) had both an inner immunoisolation membrane and an outer vascularizing membrane. Human recombinant vascular endothelial growth factor-165 was infused at 100 ng/day (low dose: n = 6) and 500 ng/day (high dose: n = 7) for 10 days into devices implanted s.c. in Sprague-Dawley rats; noninfused devices transplanted for an identical period were used as controls (n = 5). Two days following the termination of VEGF infusion, devices were loaded with 20 microl of Lispro insulin (1 U/kg) and the kinetics of insulin release from the lumen of the device was assessed. Devices were then explanted and the number of blood vessels (capillary and noncapillary) was quantified using morphometry. High-dose vascular endothelial growth factor infusion resulted in two- to threefold more blood vessels around the device than that obtained with the noninfused devices and devices infused with low-dose vascular endothelial growth factor. This increase in the number of blood vessels was accompanied by a modest increase in insulin diffusion from the device in the high-dose vascular endothelial growth factor infusion group. We conclude that vascular endothelial growth factor can be used to improve blood vessel formation adjacent to planar membrane diffusion devices.

  14. Vascular risk factors, cognitve decline, and dementia

    Directory of Open Access Journals (Sweden)

    E Duron

    2008-04-01

    Full Text Available E Duron, Olivier HanonBroca Hospital, Paris, FranceAbstract: Dementia is one of the most important neurological disorders in the elderly. Aging is associated with a large increase in the prevalence and incidence of degenerative (Alzheimer’s disease and vascular dementia, leading to a devastating loss of autonomy. In view of the increasing longevity of populations worldwide, prevention of dementia has turned into a major public health challenge. In the past decade, several vascular risk factors have been found to be associated with vascular dementia but also Alzheimer’s disease. Some longitudinal studies, have found significant associations between hypertension, diabetus mellitus, and metabolic syndrome, assessed at middle age, and dementia. Studies assessing the link between hypercholesterolemia, atrial fibrillation, smoking, and dementia have given more conflicting results. Furthermore, some studies have highlighted the possible protective effect of antihypertensive therapy on cognition and some trials are evaluating the effects of statins and treatments for insulin resistance. Vascular risk factors and their treatments are a promising avenue of research for prevention of dementia, and further long-term, placebo-controlled, randomized studies, need to be performed.Keywords: dementia, hypertension, diabetus mellitus, hypercholesterolemia, metabolic syndrome

  15. Absorb bioresorbable vascular scaffold versus everolimus-eluting metallic stent in ST-segment elevation myocardial infarction: 1-year results of a propensity score matching comparison: the BVS-EXAMINATION Study (bioresorbable vascular scaffold-a clinical evaluation of everolimus eluting coronary stents in the treatment of patients with ST-segment elevation myocardial infarction).

    Science.gov (United States)

    Brugaletta, Salvatore; Gori, Tommaso; Low, Adrian F; Tousek, Petr; Pinar, Eduardo; Gomez-Lara, Josep; Scalone, Giancarla; Schulz, Eberhard; Chan, Mark Y; Kocka, Viktor; Hurtado, Jose; Gomez-Hospital, Juan Antoni; Münzel, Thomas; Lee, Chi-Hang; Cequier, Angel; Valdés, Mariano; Widimsky, Petr; Serruys, Patrick W; Sabaté, Manel

    2015-01-01

    The purpose of this study was to compare the 1-year outcome between bioresorbable vascular scaffold (BVS) and everolimus-eluting metallic stent (EES) in ST-segment elevation myocardial infarction (STEMI) patients. The Absorb BVS (Abbott Vascular, Santa Clara, California) is a polymeric scaffold approved for treatment of stable coronary lesions. Limited and not randomized data are available on its use in ST-segment elevation myocardial infarction (STEMI) patients. This study included 290 consecutive STEMI patients treated by BVS, compared with either 290 STEMI patients treated with EES or 290 STEMI patients treated with bare-metal stents (BMS) from the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-segment Elevation Myocardial Infarction) trial, by applying propensity score matching. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization, at 1-year follow-up. Device thrombosis, according to the Academic Research Consortium criteria, was also evaluated. The cumulative incidence of DOCE did not differ between the BVS and EES or BMS groups either at 30 days (3.1% vs. 2.4%, hazard ratio [HR]: 1.31 [95% confidence interval (CI): 0.48 to 3.52], p = 0.593; vs. 2.8%, HR: 1.15 [95% CI: 0.44 to 2.30], p = 0.776, respectively) or at 1 year (4.1% vs. 4.1%, HR: 0.99 [95% CI: 0.23 to 4.32], p = 0.994; vs. 5.9%, HR: 0.50 [95% CI: 0.13 to 1.88], p = 0.306, respectively). Definite/probable BVS thrombosis rate was numerically higher either at 30 days (2.1% vs. 0.3%, p = 0.059; vs. 1.0%, p = 0.324, respectively) or at 1 year (2.4% vs. 1.4%, p = 0.948; vs. 1.7%, p = 0.825, respectively), as compared with EES or BMS. At 1-year follow-up, STEMI patients treated with BVS showed similar rates of DOCE compared with STEMI patients treated with EES or BMS, although rate of scaffolds thrombosis, mostly clustered in the early phase

  16. Information geometry of Gaussian channels

    International Nuclear Information System (INIS)

    Monras, Alex; Illuminati, Fabrizio

    2010-01-01

    We define a local Riemannian metric tensor in the manifold of Gaussian channels and the distance that it induces. We adopt an information-geometric approach and define a metric derived from the Bures-Fisher metric for quantum states. The resulting metric inherits several desirable properties from the Bures-Fisher metric and is operationally motivated by distinguishability considerations: It serves as an upper bound to the attainable quantum Fisher information for the channel parameters using Gaussian states, under generic constraints on the physically available resources. Our approach naturally includes the use of entangled Gaussian probe states. We prove that the metric enjoys some desirable properties like stability and covariance. As a by-product, we also obtain some general results in Gaussian channel estimation that are the continuous-variable analogs of previously known results in finite dimensions. We prove that optimal probe states are always pure and bounded in the number of ancillary modes, even in the presence of constraints on the reduced state input in the channel. This has experimental and computational implications. It limits the complexity of optimal experimental setups for channel estimation and reduces the computational requirements for the evaluation of the metric: Indeed, we construct a converging algorithm for its computation. We provide explicit formulas for computing the multiparametric quantum Fisher information for dissipative channels probed with arbitrary Gaussian states and provide the optimal observables for the estimation of the channel parameters (e.g., bath couplings, squeezing, and temperature).

  17. LASER TREATMENT OF BENIGN CUTANEOUS VASCULAR LESIONS

    Directory of Open Access Journals (Sweden)

    Uroš Ahčan

    2004-07-01

    Full Text Available Background. Congenital and acquired vascular lesions of the skin and subcutis are a common health problem from aesthetic and also from psycho-social point of view. However, recent advances in laser technology have enabled an efficient and safe treatment. This study presents our experience with treatment of cutaneous vascular lesions using modern laser systems. Most common benign cutaneous vascular lesions are described.Patients and methods. In years 2002 and 2003, 109 patients, 4 to 80 (mean 39 years old, Fitzpatrick skin type 1–4, with 210 benign cutaneous vascular lesions were treated using the Dualis VP® laser system (Fotona, Slovenia which incorporates the KTP and Nd:YAG lasers. Vascular lesions in the upper layers of the skin with diameter up to 1 mm were treated with the KTP laser (wavelength 532 nm. For larger vessels in deeper layer we used the Nd:YAG laser (wavelength 1064 nm. Patients graded the pain during treatment on a scale of 1–10. Clinical outcomes were evaluated 1–3 months after the last treatment: according to the percentage of clearance of the lesion compared to the adjacent normal skin and for the presence of adverse effects. According to these criteria each lesion was assigned a score: poor (0–25%, fair (26–50%, good (51–75%, excellent (76–100%.Results. Immediate response after application of a laser beam with proper characteristics was whitish-grey discoloration of treated area. Treatment results after 1–3 months were excellent in 48.1%, good 40.9%, fair in 8.6% and poor in 2.4%. Patients without prior anaesthesia graded pain during treatment from 1 to 8 (mean 4.0 and patients with EMLA® anaesthesia from 1 to 6 (mean 2.6. Side effects were frequent but minimal and transient. Erythema disappeared in several days after treatment while crusting persisted for 14 days. 3 permanent hyperpigmentations, 2 permanent hypopigmentations, 2 hypertrophic scars and 1 beam sized atrophic scar were detected at last follow

  18. Experimentation with PEC channel prototype

    International Nuclear Information System (INIS)

    Caponetti, R.; Iacovelli, M.

    1984-01-01

    Experimentation on prototypes of PEC components is presently being carried out at Casaccia CRE. This report shows the results of the first cycle of experimentation of the central channel, concerning the aspects of sodium removal after experimentation

  19. A biodegradable vascularizing membrane: a feasibility study.

    Science.gov (United States)

    Kaushiva, Anchal; Turzhitsky, Vladimir M; Darmoc, Marissa; Backman, Vadim; Ameer, Guillermo A

    2007-09-01

    Regenerative medicine and in vivo biosensor applications require the formation of mature vascular networks for long-term success. This study investigated whether biodegradable porous membranes could induce the formation of a vascularized fibrous capsule and, if so, the effect of degradation kinetics on neovascularization. Poly(l-lactic acid) (PLLA) and poly(dl-lactic-co-glycolic) acid (PLGA) membranes were created by a solvent casting/salt leaching method. Specifically, PLLA, PLGA 75:25 and PLGA 50:50 polymers were used to vary degradation kinetics. The membranes were designed to have an average 60mum pore diameter, as this pore size has been shown to be optimal for inducing blood vessel formation around nondegradable polymer materials. Membrane samples were imaged by scanning electron microscopy at several time points during in vitro degradation to assess any changes in pore structure. The in vivo performance of the membranes was assessed in Sprague-Dawley rats by measuring vascularization within the fibrous capsule that forms adjacent to implants. The vascular density within 100microm of the membranes was compared with that seen in normal tissue, and to that surrounding the commercially available vascularizing membrane TheraCyte. The hemoglobin content of tissue containing the membranes was measured by four-dimensional elastic light scattering as a novel method to assess tissue perfusion. Results from this study show that slow-degrading membranes induce greater amounts of neovascularization and a thinner fibrous capsule relative to fast degrading membranes. These results may be due both to an initially increased number of macrophages surrounding the slower degrading membranes and to the maintenance of their initial pore structure.

  20. Vascular disease in cocaine addiction.

    Science.gov (United States)

    Bachi, Keren; Mani, Venkatesh; Jeyachandran, Devi; Fayad, Zahi A; Goldstein, Rita Z; Alia-Klein, Nelly

    2017-07-01

    Cocaine, a powerful vasoconstrictor, induces immune responses including cytokine elevations. Chronic cocaine use is associated with functional brain impairments potentially mediated by vascular pathology. Although the Crack-Cocaine epidemic has declined, its vascular consequences are increasingly becoming evident among individuals with cocaine use disorder of that period, now aging. Paradoxically, during the period when prevention efforts could make a difference, this population receives psychosocial treatment at best. We review major postmortem and in vitro studies documenting cocaine-induced vascular toxicity. PubMed and Academic Search Complete were used with relevant terms. Findings consist of the major mechanisms of cocaine-induced vasoconstriction, endothelial dysfunction, and accelerated atherosclerosis, emphasizing acute, chronic, and secondary effects of cocaine. The etiology underlying cocaine's acute and chronic vascular effects is multifactorial, spanning hypertension, impaired homeostasis and platelet function, thrombosis, thromboembolism, and alterations in blood flow. Early detection of vascular disease in cocaine addiction by multimodality imaging is discussed. Treatment may be similar to indications in patients with traditional risk-factors, with few exceptions such as enhanced supportive care and use of benzodiazepines and phentolamine for sedation, and avoiding β-blockers. Given the vascular toxicity cocaine induces, further compounded by smoking and alcohol comorbidity, and interacting with aging of the crack generation, there is a public health imperative to identify pre-symptomatic markers of vascular impairments in cocaine addiction and employ preventive treatment to reduce silent disease progression. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. [The future of vascular medicine].

    Science.gov (United States)

    Kroeger, K; Luther, B

    2014-10-01

    In the future vascular medicine will still have a great impact on health of people. It should be noted that the aging of the population does not lead to a dramatic increase in patient numbers, but will be associated with a changing spectrum of co-morbidities. In addition, vascular medical research has to include the intensive care special features of vascular patients, the involvement of vascular medicine in a holistic concept of fast-track surgery, a geriatric-oriented intensive monitoring and early geriatric rehabilitation. For the future acceptance of vascular medicine as a separate subject area under delimitation of cardiology and radiology is important. On the other hand, the subject is so complex and will become more complex in future specialisations that mixing of surgery and angiology is desirable, with the aim to preserve the vascular surgical knowledge and skills on par with the medical and interventional measures and further develop them. Only large, interdisciplinary guided vascular centres will be able to provide timely diagnosis and therapy, to deal with the growing multi-morbidity of the patient, to perform complex therapies even in an acute emergency and due to sufficient number of cases to present with well-trained and experienced teams. These requirements are mandatory to decrease patients' mortality step by step. Georg Thieme Verlag KG Stuttgart · New York.

  2. Contemporary vascular smartphone medical applications.

    Science.gov (United States)

    Carter, Thomas; O'Neill, Stephen; Johns, Neil; Brady, Richard R W

    2013-08-01

    Use of smartphones and medical mHealth applications (apps) within the clinical environment provides a potential means for delivering elements of vascular care. This article reviews the contemporary availability of apps specifically themed to major vascular diseases and the opportunities and concerns regarding their integration into practice. Smartphone apps relating to major vascular diseases were identified from the app stores for the 6 most popular smartphone platforms, including iPhone, Android, Blackberry, Nokia, Windows, and Samsung. Search terms included peripheral artery (arterial) disease, varicose veins, aortic aneurysm, carotid artery disease, amputation, ulcers, hyperhydrosis, thoracic outlet syndrome, vascular malformation, and lymphatic disorders. Forty-nine vascular-themed apps were identified. Sixteen (33%) were free of charge. Fifteen apps (31%) had customer satisfaction ratings, but only 3 (6%) had greater than 100. Only 13 apps (27%) had documented medical professional involvement in their design or content. The integration of apps into the delivery of care has the potential to benefit vascular health care workers and patients. However, high-quality apps designed by clinicians with vascular expertise are currently lacking and represent an area of concern in the mHealth market. Improvement in the quality and reliability of these apps will require the development of robust regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Results of tests and studies of American materials in the channel of the MHD facility U-02 (Phase III). [LaCrO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Burenkov, D.K.; Borodina, T.I.; Vysotsky, D.A.; Zalkind, V.I.; Kirillov, V.V.; Romanov, A.I.; Telegin, G.P.; Strekalov, N.V.

    1978-10-01

    In accordance with the US--USSR Cooperative Program in MHD joint US--USSR tests were conducted in May 1978 at the U-02 facility of an MHD generator section consisting of U.S.-built electrode blocks and USSR-built insulating walls. The main purpose of the experiment was to conduct continuous 100-hour duration tests of materials and structures of electrode blocks; in particular, to study the behavior of ceramic electrodes and insulators in operating conditions of an MHD generator, the electro-physical and thermal characteristics of the working section as a whole and electrodes in particular, and to analyze the change in the phase composition and structure of materials during the test. The main thrust of the experiment was a study of electrode material behavior. Six varieties of electrodes based on doped lanthanum chromite were tested and investigated. The electrodes were made of fine grained, hot-pressed mass (the porosity of the ceramic was 2 to 3%). The interelectrode insulators were made of magnesial and magnesial-spinel ceramic also manufactured by the hot pressing method. Results are presented and discussed.

  4. Economic Outcomes of Bioresorbable Vascular Scaffolds Versus Everolimus-Eluting Stents in Patients Undergoing Percutaneous Coronary Intervention: 1-Year Results From the ABSORB III Trial.

    Science.gov (United States)

    Baron, Suzanne J; Lei, Yang; Chinnakondepalli, Khaja; Vilain, Katherine; Magnuson, Elizabeth A; Kereiakes, Dean J; Ellis, Stephen G; Stone, Gregg W; Cohen, David J

    2017-04-24

    The purpose of this study was to evaluate the economic impact of the Absorb bioresorbable vascular scaffold compared with the Xience everolimus-eluting stent in patients undergoing percutaneous coronary intervention. The ABSORB III trial (Everolimus-Eluting Bioresorbable Scaffolds for Coronary Artery Disease) demonstrated that the Absorb scaffold was noninferior to the Xience stent with respect to target lesion failure at 1 year. Whether health care costs differ between the Absorb scaffold and the Xience stent is unknown. We performed a prospective health economic study alongside the ABSORB III trial, in which patients undergoing percutaneous coronary intervention for stable or unstable angina were randomized to receive the Absorb scaffold (n = 1,322) or Xience stent (n = 686). Resource use data were collected through 1 year of follow-up. Costs were assessed using resource-based accounting (for procedures), MedPAR data (for other index hospitalization costs), and Medicare reimbursements (for follow-up costs and physician fees). Initial procedural costs were higher with the Absorb scaffold than the Xience stent ($6,316 ± 1,892 vs. $6,103 ± 1,895; p = 0.02), driven mainly by greater balloon catheter use and the higher cost of the scaffold in the Absorb group. Nonetheless, index hospitalization costs ($15,035 ± 2,992 for Absorb vs. $14,903 ± 3,449 for Xience; p = 0.37) and total 1-year costs ($17,848 ± 6,110 for Absorb vs. $17,498 ± 7,411 for Xience; p = 0.29) were similar between the 2 groups. Although initial procedural costs were higher with the Absorb scaffold, there were no differences in total 1-year health care costs between the 2 cohorts. Longer term follow-up is needed to determine whether meaningful cost savings emerge after scaffold resorption. (A Clinical Evaluation of Absorb™ BVS, the Everolimus-Eluting Bioresorbable Vascular Scaffold in the Treatment of Subjects With de Novo Native Coronary Artery Lesions; NCT01751906). Copyright © 2017

  5. Coexistence of pheochromocytoma with uncommon vascular lesions

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Kota

    2012-01-01

    Full Text Available Background: Pheochromocytoma/paragangliomas have been described to be associated with rare vascular abnormalities like renal artery stenosis. Coexistence of physiologically significant renal artery lesions is a compounding factor that alters management and prognosis of pheochromocytoma patients. Apart from individual case reports, data on such association in Indian population is not available. The aim of this study is to find the nature and prevalence of associated vascular abnormalities. Materials and Methods: From 1990 to 2010, a total of 50 patients were diagnosed with pheochromocytoma/paragangliomas. Hospital charts of these patients were reviewed retrospectively to identify those with unusual vascular abnormalities. Available literature was also reviewed. Results: Of the 50 patients with pheochromocytoma, 7 (14% had coexisting vascular lesions including renal artery stenosis in 4, aortoarteritis in 1, aortic aneurysm in 1 and inferior vena cava thrombosis in 1. Pheochromocytoma was adrenal in 42 and extra adrenal in 8. Laparoscopic adrenalectomy was done in the patients. One patient with renal artery stenosis due to intimal fibrosis was subjected to percutaneous balloon angioplasty; the other three improved after adrenalectomy and lysis of fibrous adhesive bands. The patient with aortoarteritos was treated with oral steroids. Inferior vena cava thrombosis was reversed with anticoagulants. The patient with abdominal aortic aneurysm was advised for annual follow-up on account of its size of 4.5 cm and asymptomatic presentation. Conclusion: There are multiple mechanisms that can lead to renal artery stenosis and other vascular abnormalities in a case of pheochromocytoma. A high index of suspicion is necessary to enable both entities to be diagnosed preoperatively and allow proper planning of surgical therapy. Incomplete diagnosis may lead to persistent hypertension postoperatively in a case of associated renal artery stenosis.

  6. The making of indigenous vascular prosthesis

    Directory of Open Access Journals (Sweden)

    Madathipat Unnikrishnan

    2016-01-01

    Full Text Available Background & objectives: Vascular illnesses are on the rise in India, due to increase in lifestyle diseases and demographic transition, requiring intervention to save life, organ or limbs using vascular prosthesis. The aim of this study was to develop indigenous large diameter vascular graft for treatment of patients with vascular pathologies. Methods: The South India Textile Research Association, at Coimbatore, Tamil Nadu, India, developed seamless woven polyester (Polyethylene terephthalate graft at its research wing. Further characterization and testing followed by clinical trials were conducted at Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. Fifteen in vivo experiments were carried out in 1992-1994 in pigs as animal model. Controlled (phase I clinical trial in ten patients was performed along with control graft. Thereafter, phase II trial involved 22 patients who underwent multi-centre clinical trial in four centres across India. Results: Laboratory testing showed that polyester graft was non-toxic, non-leeching and non-haemolytic with preserved long-term quality, further confirming in pigs by implanting in thoracic aorta, comparable to control Dacron grafts. Perigraft incorporation and smooth neointima formation which are prime features of excellent healing characteristics, were noted at explantation at planned intervals. Subsequently in the phase I and II clinical trials, all patients had excellent recovery without mortality or device-related adverse events. Patients receiving the test graft were followed up for 10 and 5 years, respectively. Serial clinical, duplex scans and CT angiograms performed periodically confirmed excellent graft performance. Interpretation & conclusions: Indigenously developed Chitra vascular graft was comparable to commercially available Dacron graft, ready for clinical use at affordable cost to patients as against costly imported grafts.

  7. Inward rectifier potassium (Kir2.1) channels as end‐stage boosters of endothelium‐dependent vasodilators

    Science.gov (United States)

    Dalsgaard, Thomas; Bonev, Adrian D.; Nelson, Mark T.

    2016-01-01

    Key points Increase in endothelial cell (EC) calcium activates calcium‐sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium‐dependent vasodilatation.Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium‐dependent vasodilatation is not clear.In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform.Endothelium‐dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown.These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Abstract Endothelium‐dependent vasodilators, such as acetylcholine, increase intracellular Ca2+ through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca2+‐sensitive intermediate and small conductance K+ (IK and SK, respectively) channels. Although strong inward rectifier K+ (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC‐dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC‐dependent vasodilatation of resistance‐sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC‐specific Kir2.1 knockdown (EC‐Kir2.1 −/−) mice. Elevation of extracellular K+ to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial

  8. Quantum Correlations Evolution Asymmetry in Quantum Channels

    International Nuclear Information System (INIS)

    Li Meng; Huang Yun-Feng; Guo Guang-Can

    2017-01-01

    It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entanglement and quantum discord, evolution asymmetry to various quantum channels. We found that the asymmetry of entanglement and quantum discord only occurs in some special quantum channels, and the behavior of the entanglement evolution may be quite different from the behavior of the quantum discord evolution. To quantum entanglement, in some channels it decreases monotonously with the increase of the quantum channel intensity. In some other channels, when we increase the intensity of the quantum channel, it decreases at first, then keeps zero for some time, and then rises up. To quantum discord, the evolution becomes more complex and you may find that it evolutes unsmoothly at some points. These results illustrate the strong dependence of the quantum correlations evolution on the property of the quantum channels. (paper)

  9. Channel Estimation in DCT-Based OFDM

    Science.gov (United States)

    Wang, Yulin; Zhang, Gengxin; Xie, Zhidong; Hu, Jing

    2014-01-01

    This paper derives the channel estimation of a discrete cosine transform- (DCT-) based orthogonal frequency-division multiplexing (OFDM) system over a frequency-selective multipath fading channel. Channel estimation has been proved to improve system throughput and performance by allowing for coherent demodulation. Pilot-aided methods are traditionally used to learn the channel response. Least square (LS) and mean square error estimators (MMSE) are investigated. We also study a compressed sensing (CS) based channel estimation, which takes the sparse property of wireless channel into account. Simulation results have shown that the CS based channel estimation is expected to have better performance than LS. However MMSE can achieve optimal performance because of prior knowledge of the channel statistic. PMID:24757439

  10. Geysering in boiling channels

    Energy Technology Data Exchange (ETDEWEB)

    Aritomi, Masanori; Takemoto, Takatoshi [Tokyo Institute of Technology, Tokyo (Japan); Chiang, Jing-Hsien [Japan NUS Corp. Ltd., Toyko (Japan)] [and others

    1995-09-01

    A concept of natural circulation BWRs such as the SBWR has been proposed and seems to be promising in that the primary cooling system can be simplified. The authors have been investigating thermo-hydraulic instabilities which may appear during the start-up in natural circulation BWRs. In our previous works, geysering was investigated in parallel boiling channels for both natural and forced circulations, and its driving mechanism and the effect of system pressure on geysering occurrence were made clear. In this paper, geysering is investigated in a vertical column and a U-shaped vertical column heated in the lower parts. It is clarified from the results that the occurrence mechanism of geysering and the dependence of system pressure on geysering occurrence coincide between parallel boiling channels in circulation systems and vertical columns in non-circulation systems.

  11. Coolant channel module CCM

    International Nuclear Information System (INIS)

    Hoeld, Alois

    2007-01-01

    A complete and detailed description of the theoretical background of an '(1D) thermal-hydraulic drift-flux based mixture-fluid' coolant channel model and its resulting module CCM will be presented. The objective of this module is to simulate as universally as possible the steady state and transient behaviour of the key characteristic parameters of a single- or two-phase fluid flowing within any type of heated or non-heated coolant channel. Due to the possibility that different flow regimes can appear along any channel, such a 'basic (BC)' 1D channel is assumed to be subdivided into a number of corresponding sub-channels (SC-s). Each SC can belong to only two types of flow regime, an SC with just a single-phase fluid, containing exclusively either sub-cooled water or superheated steam, or an SC with a two-phase mixture flow. After an appropriate nodalisation of such a BC (and therefore also its SC-s) a 'modified finite volume method' has been applied for the spatial discretisation of the partial differential equations (PDE-s) which represent the basic conservation equations of thermal-hydraulics. Special attention had to be given to the possibility of variable SC entrance or outlet positions (which describe boiling boundaries or mixture levels) and thus the fact that an SC can even disappear or be created anew. The procedure yields for each SC type (and thus the entire BC), a set of non-linear ordinary 1st order differential equations (ODE-s). To link the resulting mean nodal with the nodal boundary function values, both of which are present in the discretised differential equations, a special quadratic polygon approximation procedure (PAX) had to be constructed. Together with the very thoroughly tested packages for drift-flux, heat transfer and single- and two-phase friction factors this procedure represents the central part of the here presented 'Separate-Region' approach, a theoretical model which provides the basis to the very effective working code package CCM

  12. Vascular Contributions to Cognitive Impairment and Dementia

    Science.gov (United States)

    Gorelick, Philip B.; Scuteri, Angelo; Black, Sandra E.; DeCarli, Charles; Greenberg, Steven M.; Iadecola, Costantino; Launer, Lenore J.; Laurent, Stephane; Lopez, Oscar L.; Nyenhuis, David; Petersen, Ronald C.; Schneider, Julie A.; Tzourio, Christophe; Arnett, Donna K.; Bennett, David A.; Chui, Helena C.; Higashida, Randall T.; Lindquist, Ruth; Nilsson, Peter M.; Roman, Gustavo C.; Sellke, Frank W.; Seshadri, Sudha

    2013-01-01

    Background and Purpose This scientific statement provides an overview of the evidence on vascular contributions to cognitive impairment and dementia. Vascular contributions to cognitive impairment and dementia of later life are common. Definitions of vascular cognitive impairment (VCI), neuropathology, basic science and pathophysiological aspects, role of neuroimaging and vascular and other associated risk factors, and potential opportunities for prevention and treatment are reviewed. This statement serves as an overall guide for practitioners to gain a better understanding of VCI and dementia, prevention, and treatment. Methods Writing group members were nominated by the writing group co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council Scientific Statement Oversight Committee, the Council on Epidemiology and Prevention, and the Manuscript Oversight Committee. The writing group used systematic literature reviews (primarily covering publications from 1990 to May 1, 2010), previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. After peer review by the American Heart Association, as well as review by the Stroke Council leadership, Council on Epidemiology and Prevention Council, and Scientific Statements Oversight Committee, the statement was approved by the American Heart Association Science Advisory and Coordinating Committee. Results The construct of VCI has been introduced to capture the entire spectrum of cognitive disorders associated with all forms of cerebral vascular brain injury—not solely stroke—ranging from mild cognitive impairment through fully developed

  13. In vivo endothelization of tubular vascular grafts through in situ recruitment of endothelial and endothelial progenitor cells by RGD-fused mussel adhesive proteins

    International Nuclear Information System (INIS)

    Kang, Tae-Yun; Lee, Jung Ho; Kang, Jo-A; Rhie, Jong-Won; Kim, Bum Jin; Cha, Hyung Joon; Hong, Jung Min; Kim, Byoung Soo; Cho, Dong-Woo

    2015-01-01

    The use of tissue mimics in vivo, including patterned vascular networks, is expected to facilitate the regeneration of functional tissues and organs with large volumes. Maintaining patency of channels in contact with blood is an important issue in the development of a functional vascular network. Endothelium is the only known completely non-thrombogenic material; however, results from treatments to induce endothelialization are inconclusive. The present study was designed to evaluate the clinical applicability of in situ recruitment of endothelial cells/endothelial progenitor cells (EC/EPC) and pre-endothelization using a recombinant mussel adhesive protein fused with arginine–glycine–aspartic acid peptide (MAP-RGD) coating in a model of vascular graft implantation. Microporous polycaprolactone (PCL) scaffolds were fabricated with salt leaching methods and their surfaces were modified with collagen and MAP-RGD. We then evaluated their anti-thrombogenicity with an in vitro hemocompatibility assessment and a 4-week implantation in the rabbit carotid artery. We observed that MAP-RGD coating reduced the possibility of early in vivo graft failure and enhanced re-endothelization by in situ recruitment of EC/EPC (patency rate: 2/3), while endothelization prior to implantation aggravated the formation of thrombosis and/or IH (patency rate: 0/3). The results demonstrated that in situ recruitment of EC/EPC by MAP-RGD could be a promising strategy for vascular applications. In addition, it rules out several issues associated with pre-endothelization, such as cell source, purity, functional modulation and contamination. Further evaluation of long term performance and angiogenesis from the luminal surface may lead to the clinical use of MAP-RGD for tubular vascular grafts and regeneration of large-volume tissues with functional vascular networks. (paper)

  14. Citizens and service channels: channel choice and channel management implications

    NARCIS (Netherlands)

    Pieterson, Willem Jan

    2010-01-01

    The arrival of electronic channels in the 1990s has had a huge impact on governmental service delivery. The new channels have led to many new opportunities to improve public service delivery, not only in terms of citizen satisfaction, but also in cost reduction for governmental agencies. However,

  15. Vascular graft infections with Mycoplasma

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Skov Jensen, J; Prag, J

    1995-01-01

    laboratory techniques, the percentage of culture-negative yet grossly infected vascular grafts seems to be increasing and is not adequately explained by the prior use of antibiotics. We have recently reported the first case of aortic graft infection with Mycoplasma. We therefore suggest the hypothesis...... that the large number of culture-negative yet grossly infected vascular grafts may be due to Mycoplasma infection not detected with conventional laboratory technique....

  16. Limb vascular function in women

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Gliemann, Lasse

    2018-01-01

    Throughout life, women are subjected to both acute fluctuations in sex hormones, associated with the menstrual cycle, and chronic changes following the onset of menopause. Female sex hormones, and in particular estrogen, strongly influence cardiovascular function such as the regulation of vascular...... studies. Physical activity should be recommended for women of all ages, but the most essential timing for maintenance of vascular health may be from menopause and onwards....

  17. Facial vascular malformations in children

    International Nuclear Information System (INIS)

    Brunelle, F.O.; Lallemand, D.; Chaumont, P.; Teillac, D.; Manach, Y.

    1988-01-01

    The authors present their experience with conventional and digital angiography of vascular malformations of the head and neck in children. 22 hemangioendotheliomas, 8 venous angiomas, and 3 arteriovenous fistula were studied. 22 patients were embolised. DSA offers many advantages during the diagnostic as well as during the therapeutic phase of angiography. Embolization appears to have a major role in treatment of such vascular malformations. (orig.)

  18. Retinal vascular segmentation using superpixel-based line operator and its application to vascular topology estimation.

    Science.gov (United States)

    Na, Tong; Xie, Jianyang; Zhao, Yitian; Zhao, Yifan; Liu, Yue; Wang, Yongtian; Liu, Jiang

    2018-05-09

    Automatic methods of analyzing of retinal vascular networks, such as retinal blood vessel detection, vascular network topology estimation, and arteries/veins classification are of great assistance to the ophthalmologist in terms of diagnosis and treatment of a wide spectrum of diseases. We propose a new framework for precisely segmenting retinal vasculatures, constructing retinal vascular network topology, and separating the arteries and veins. A nonlocal total variation inspired Retinex model is employed to remove the image intensity inhomogeneities and relatively poor contrast. For better generalizability and segmentation performance, a superpixel-based line operator is proposed as to distinguish between lines and the edges, thus allowing more tolerance in the position of the respective contours. The concept of dominant sets clustering is adopted to estimate retinal vessel topology and classify the vessel network into arteries and veins. The proposed segmentation method yields competitive results on three public data sets (STARE, DRIVE, and IOSTAR), and it has superior performance when compared with unsupervised segmentation methods, with accuracy of 0.954, 0.957, and 0.964, respectively. The topology estimation approach has been applied to five public databases (DRIVE,STARE, INSPIRE, IOSTAR, and VICAVR) and achieved high accuracy of 0.830, 0.910, 0.915, 0.928, and 0.889, respectively. The accuracies of arteries/veins classification based on the estimated vascular topology on three public databases (INSPIRE, DRIVE and VICAVR) are 0.90.9, 0.910, and 0.907, respectively. The experimental results show that the proposed framework has effectively addressed crossover problem, a bottleneck issue in segmentation and vascular topology reconstruction. The vascular topology information significantly improves the accuracy on arteries/veins classification. © 2018 American Association of Physicists in Medicine.

  19. Reduction in renal blood flow following administration of norepinephrine and phenylephrine in septic rats treated with Kir6.1 ATP-sensitive and KCa1.1 calcium-activated K+ channel blockers.

    Science.gov (United States)

    da Rosa Maggi Sant'Helena, Bruna; Guarido, Karla L; de Souza, Priscila; Crestani, Sandra; da Silva-Santos, J Eduardo

    2015-10-15

    We evaluated the effects of K+ channel blockers in the vascular reactivity of in vitro perfused kidneys, as well as on the influence of vasoactive agents in the renal blood flow of rats subjected to the cecal ligation and puncture (CLP) model of sepsis. Both norepinephrine and phenylephrine had the ability to increase the vascular perfusion pressure reduced in kidneys of rats subjected to CLP at 18 h and 36 h before the experiments. The non-selective K+ channel blocker tetraethylammonium, but not the Kir6.1 blocker glibenclamide, normalized the effects of phenylephrine in kidneys from the CLP 18 h group. Systemic administration of tetraethylammonium, glibenclamide, or the KCa1.1 blocker iberiotoxin, did not change the renal blood flow in control or septic rats. Norepinephrine or phenylephrine also had no influence on the renal blood flow of septic animals, but its injection in rats from the CLP 18 h group previously treated with either glibenclamide or iberiotoxin resulted in an exacerbated reduction in the renal blood flow. These results suggest an abnormal functionality of K+ channels in the renal vascular bed in sepsis, and that the blockage of different subtypes of K+ channels may be deleterious for blood perfusion in kidneys, mainly when associated with vasoactive drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Channel Simulation in Quantum Metrology

    Directory of Open Access Journals (Sweden)

    Laurenza Riccardo

    2018-04-01

    Full Text Available In this review we discuss how channel simulation can be used to simplify the most general protocols of quantum parameter estimation, where unlimited entanglement and adaptive joint operations may be employed. Whenever the unknown parameter encoded in a quantum channel is completely transferred in an environmental program state simulating the channel, the optimal adaptive estimation cannot beat the standard quantum limit. In this setting, we elucidate the crucial role of quantum teleportation as a primitive operation which allows one to completely reduce adaptive protocols over suitable teleportation-covariant channels and derive matching upper and lower bounds for parameter estimation. For these channels,wemay express the quantum Cramér Rao bound directly in terms of their Choi matrices. Our review considers both discrete- and continuous-variable systems, also presenting some new results for bosonic Gaussian channels using an alternative sub-optimal simulation. It is an open problem to design simulations for quantum channels that achieve the Heisenberg limit.

  1. Vascular Complications of Pancreatitis: Role of Interventional Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Barge, Jaideep U.; Lopera, Jorge E. [University of Texas Health Science Center, San Antonio (United States)

    2012-02-15

    Major vascular complications related to pancreatitis can cause life-threatening hemorrhage and have to be dealt with as an emergency, utilizing a multidisciplinary approach of angiography, endoscopy or surgery. These may occur secondary to direct vascular injuries, which result in the formation of splanchnic pseudoaneurysms, gastrointestinal etiologies such as peptic ulcer disease and gastroesophageal varices, and post-operative bleeding related to pancreatic surgery. In this review article, we discuss the pathophysiologic mechanisms, diagnostic modalities, and treatment of pancreatic vascular complications, with a focus on the role of minimally-invasive interventional therapies such as angioembolization, endovascular stenting, and ultrasound-guided percutaneous thrombin injection in their management.

  2. Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

    Directory of Open Access Journals (Sweden)

    Darryl W Hondorp

    Full Text Available Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens into commercial navigation channels, potentially increasing their exposure to ship strikes. To address this question, we quantified and compared Lake Sturgeon selection for navigation channels vs. alternative pathways in two multi-channel rivers differentially affected by channelization, but free of barriers to sturgeon movement. Acoustic telemetry was used to quantify Lake Sturgeon movements. Under the assumption that Lake Sturgeon navigate by following primary flow paths, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River were expected to choose navigation channels over alternative pathways and to exhibit greater selection for navigation channels than conspecifics in the less-channelized lower St. Clair River. Consistent with these predictions, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River selected the higher-flow and deeper navigation channels over alternative migration pathways, whereas in the less-channelized lower St. Clair River, individuals primarily used pathways alternative to navigation channels. Lake Sturgeon selection for navigation channels as migratory pathways also was significantly higher in the more-channelized lower Detroit River than in the less-channelized lower St. Clair River. We speculated that use of navigation channels over alternative pathways would increase the spatial overlap of commercial vessels and migrating Lake Sturgeon, potentially enhancing their vulnerability to ship strikes. Results of our study thus demonstrated an association between channelization and the path use of migrating Lake Sturgeon that could prove

  3. Calcium dynamics in vascular smooth muscle

    OpenAIRE

    Amberg, Gregory C.; Navedo, Manuel F.

    2013-01-01

    Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

  4. The Vascular Factor Plays the Main Role in the Cause of Pain in Men with Chronic Prostatitis and Chronic Pelvic Pain Syndrome: The Results of Clinical Trial on Thermobalancing Therapy

    Directory of Open Access Journals (Sweden)

    Simon Allen

    2017-11-01

    Full Text Available Chronic pain in patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS, NIH category III is difficult to treat without understanding its cause. The main symptom of chronic prostatitis is pain. In this study, we would like to explain the origin of pain in men with CP/CPPS and its therapy. Forty-five patients with CP/CPPS have received thermobalancing therapy (TT enabled by Dr Allen’s therapeutic device (DATD for six months as mono-therapy. The control group comprised 45 men with CP/CPPS did not receive TT. Before and after six months the National Institute of Health Chronic Prostatitis Symptom Index (NIH-CPSI scores, prostatic volume (PV by ultrasound measurement and uroflowmetry (Qmax were compared between the groups. Baseline characteristics have shown no difference. After TT, significant improvements in pain score (p < 0.001, quality of life index (QoL (p < 0.001, decrease of PV (p < 0.001, and increase Qmax (p < 0.001 were determined. There were not noteworthy changes in the control group. Chronic pain due to CP/CPPS happens as a consequence and challenges at the capillary level, namely pathological capillary activity. In response to initial triggers—such as inflammation, cold, psychological and other factors—constriction and spontaneous expansion of capillaries follows, creating a continuous secondary trigger—i.e., the micro-focus of hypothermia—which in turn provokes expansion of capillaries. The additional tissue due to vascular changes into the prostate increases pressure on nociceptors causing pain. TT relieves chronic pelvic pain by eliminating the lasting focus of hypothermia in the affected prostate tissue.

  5. Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels

    Science.gov (United States)

    Li, Husheng; Betz, Sharon M.; Poor, H. Vincent

    2007-05-01

    This paper examines the performance of decision feedback based iterative channel estimation and multiuser detection in channel coded aperiodic DS-CDMA systems operating over multipath fading channels. First, explicit expressions describing the performance of channel estimation and parallel interference cancellation based multiuser detection are developed. These results are then combined to characterize the evolution of the performance of a system that iterates among channel estimation, multiuser detection and channel decoding. Sufficient conditions for convergence of this system to a unique fixed point are developed.

  6. Injuries to the vascular endothelium: vascular wall and endothelial dysfunction.

    Science.gov (United States)

    Fisher, Mark

    2008-01-01

    Vascular endothelial injury has multiple elements, and this article focuses on ischemia-related processes that have particular relevance to ischemic stroke. Distinctions between necrotic and apoptotic cell death provide a basic science context in which to better understand the significance of classical core and penumbra concepts of acute stroke, with apoptotic processes particularly prominent in the penumbra. The mitochondria are understood to serve as a reservoir of proteins that mediate apoptosis. Oxidative stress pathways generating reactive oxygen species (ROS) are prominent in endothelial injury, both ischemic and nonischemic, with prominent roles of enzyme- and nonenzymemediated pathways; mitochondria once again have a critical role, particularly in the nonenzymatic pathways generating ROS. Inflammation also contributes to vascular endothelial injury, and endothelial cells have the capacity to rapidly increase expression of inflammatory mediators following ischemic challenge; this leads to enhanced leukocyte-endothelial interactions mediated by selectins and adhesion molecules. Preconditioning consists of a minor version of an injurious event, which in turn may protect vascular endothelium from injury following a more substantial event. Presence of the blood-brain barrier creates unique responses to endothelial injury, with permeability changes due to impairment of endothelial-matrix interactions compounding altered vasomotor tone and tissue perfusion mediated by nitric oxide. Pharmacological protection against vascular endothelial injury can be provided by several of the phosphodiesterases (cilostazol and dipyridamole), along with statins. Optimal clinical responses for protection of brain vascular endothelium may use preconditioning as a model, and will likely require combined protection against apoptosis, ROS, and inflammation.

  7. Non-invasive vascular imaging: assessing tumour vascularity

    International Nuclear Information System (INIS)

    Delorme, S.; Knopp, M.V.

    1998-01-01

    Non-invasive assessment of vascularity is a new diagnostic approach to characterise tumours. Vascular assessment is based on the pathophysiology of tumour angiogenesis and its diagnostic implications for tumour biology, prognosis and therapy response. Two current techniques investigating vascular features in addition to morphology are Doppler ultrasonography and contrast-enhanced MRI. Diagnostic differentiation has been shown to be possible with Doppler, and a high degree of observed vascularity could be linked to an aggressive course of the disease. Dynamic MRI using gadolinium chelates is already used clinically to detect and differentiate tumours. The histological correlation shows that capillary permeability is increased in malignant tumours and is the best criterion for differentiation from benign processes. Permeability and perfusion factors seem to be more diagnostic than overall vessel density. New clinical applications are currently being established for therapy monitoring. Further instrumental developments will bring harmonic imaging in Doppler, and faster imaging techniques, higher spatial resolution and novel pharmacokinetic concepts in MRI. Upcoming contrast agents for both Doppler and MRI will further improve estimation of intratumoural blood volume and vascular permeability. (orig.)

  8. Sensing of Vascular Permeability in Inflamed Vessel of Live Animal

    Directory of Open Access Journals (Sweden)

    Sang A Park

    2018-01-01

    Full Text Available Increase in vascular permeability is a conclusive response in the progress of inflammation. Under controlled conditions, leukocytes are known to migrate across the vascular barriers to the sites of inflammation without severe vascular rupture. However, when inflammatory state becomes excessive, the leakage of blood components may occur and can be lethal. Basically, vascular permeability can be analyzed based on the intensity of blood outflow. To evaluate the amount and rate of leakage in live mice, we performed cremaster muscle exteriorization to visualize blood flow and neutrophil migration. Using two-photon intravital microscopy of the exteriorized cremaster muscle venules, we found that vascular barrier function is transiently and locally disrupted in the early stage of inflammatory condition induced by N-formylmethionyl-leucyl-phenylalanine (fMLP. Measurement of the concentration of intravenously (i.v. injected Texas Red dextran inside and outside the vessels resulted in clear visualization of real-time increases in transient and local vascular permeability increase in real-time manner. We successfully demonstrated repeated leakage from a target site on a blood vessel in association with increasing severity of inflammation. Therefore, compared to other methods, two-photon intravital microscopy more accurately visualizes and quantifies vascular permeability even in a small part of blood vessels in live animals in real time.

  9. Vascular Neurology Nurse Practitioner Provision of Telemedicine Consultations

    Directory of Open Access Journals (Sweden)

    Bart M. Demaerschalk

    2010-01-01

    Full Text Available Objective. The objective was to define and evaluate a role for the Vascular Neurology-Nurse Practitioner (VN-NP in the delivery of telemedicine consultations in partnership with a vascular neurologist. Methods. Prospective stroke alert patients at participating hospitals underwent a two-way audio video telemedicine consultation with a VN-NP at a remotely located stroke center in partnership with a vascular neurologist. Demographic information, National Institutes of Health Stroke Scale (NIHSS scores, diagnoses, CT contraindications to thrombolysis, thrombolysis eligibility, and time interval data were collected. The inter-rater agreement between VN-NP and vascular neurologist assessments was calculated. Results. Ten patients were evaluated. Four were determined to have ischemic stroke, one had a transient ischemic attack, two had intracerebral hemorrhages, and three were stroke mimics. Overall, three patients received thrombolysis. The inter-rater agreement between VN-NP and vascular neurologist assessments were excellent, ranging from 0.9 to 1.0. The duration of VN-NP consultation was 53.2±9.0 minutes, which included the vascular neurologist supervisory evaluation time of 12.0±9.6 minutes. Conclusion. This study illustrated that a stroke center VN-NP, in partnership with a vascular neurologist, could deliver timely telemedicine consultations, accurate diagnoses, and correct treatments in acute stroke patients who presented to remotely located rural emergency departments within a hub and spoke network. VN-NPs may fulfill the role of a telestroke provider.

  10. Vascular neurology nurse practitioner provision of telemedicine consultations.

    Science.gov (United States)

    Demaerschalk, Bart M; Kiernan, Terri-Ellen J; Investigators, Starr

    2010-01-01

    Objective. The objective was to define and evaluate a role for the Vascular Neurology-Nurse Practitioner (VN-NP) in the delivery of telemedicine consultations in partnership with a vascular neurologist. Methods. Prospective stroke alert patients at participating hospitals underwent a two-way audio video telemedicine consultation with a VN-NP at a remotely located stroke center in partnership with a vascular neurologist. Demographic information, National Institutes of Health Stroke Scale (NIHSS) scores, diagnoses, CT contraindications to thrombolysis, thrombolysis eligibility, and time interval data were collected. The inter-rater agreement between VN-NP and vascular neurologist assessments was calculated. Results. Ten patients were evaluated. Four were determined to have ischemic stroke, one had a transient ischemic attack, two had intracerebral hemorrhages, and three were stroke mimics. Overall, three patients received thrombolysis. The inter-rater agreement between VN-NP and vascular neurologist assessments were excellent, ranging from 0.9 to 1.0. The duration of VN-NP consultation was 53.2 +/- 9.0 minutes, which included the vascular neurologist supervisory evaluation time of 12.0 +/- 9.6 minutes. Conclusion. This study illustrated that a stroke center VN-NP, in partnership with a vascular neurologist, could deliver timely telemedicine consultations, accurate diagnoses, and correct treatments in acute stroke patients who presented to remotely located rural emergency departments within a hub and spoke network. VN-NPs may fulfill the role of a telestroke provider.

  11. Luteolin Ameliorates Hypertensive Vascular Remodeling through Inhibiting the Proliferation and Migration of Vascular Smooth Muscle Cells

    Directory of Open Access Journals (Sweden)

    Jie Su

    2015-01-01

    Full Text Available Objectives. Preliminary researches showed that luteolin was used to treat hypertension. However, it is still unclear whether luteolin has effect on the hypertensive complication such as vascular remodeling. The present study was designed to investigate the effect of luteolin on the hypertensive vascular remodeling and its molecular mechanism. Method and Results. We evaluated the effect of luteolin on aorta thickening of hypertension in spontaneous hypertensive rats (SHRs and found that luteolin could significantly decrease the blood pressure and media thickness of aorta in vivo. Luteolin could inhibit angiotensin II- (Ang II- induced proliferation and migration of vascular smooth muscle cells (VSMCs. Dichlorofluorescein diacetate (DCFH-DA staining result showed that luteolin reduced Ang II-stimulated ROS production in VSMCs. Furthermore, western blot and gelatin zymography results showed that luteolin treatment leaded to a decrease in ERK1/2, p-ERK1/2, p-p38, MMP2, and proliferating cell nuclear antigen (PCNA protein level. Conclusion. These data support that luteolin can ameliorate hypertensive vascular remodeling by inhibiting the proliferation and migration of Ang II-induced VSMCs. Its mechanism is mediated by the regulation of MAPK signaling pathway and the production of ROS.

  12. Role of endovascular treatment in vascular injuries

    International Nuclear Information System (INIS)

    Tahir, M.M.; Haq, T.U.

    2012-01-01

    Objective: To evaluate retrospectively the results, complications and follow-up of patients after endovascular treatment of vascular injuries. Methods: Fifty transcatheter embolisation procedures (TCE) were performed in 46 patients between 1999 and 2008 at the Aga Khan University Hospital, Karachi. Injuries in 14 (30.4%) patients were due to road traffic accident; iatrogenic in 13 (28%); accidental in 6 (13%). Firearms, bomb blasts and earthquake contributed to injuries in 8(17%), 4(8.8%) and 1(2.2%) patients respectively. All patients underwent angiography and had evidence of either active haemorrhage, pseudo-aneurysm, abnormal vascularity or arteriovenous fistula. Follow-up ranged from 1 day to 6 years with mean of 10.5 months. Medical record files, lab results and imaging reports were utilised for the study. Procedure was declared as technically successful when there was cessation of extravasation, occlusion of fistula or exclusion of pseudo-aneurysm in the post-embolisation angiograms. Treatment was deemed clinically successful if there was resolution of the indication for which the procedure was done. Results: Transcatheter embolisation was technically successful in occluding vascular lesions in all 46 (100%) patients. Lesions recurred in 4 (9%) patients who underwent initially successful TCE. These patients were treated effectively with repeated TCE. Three patients died during the same hospital stay and 3 patients died after being discharged from the hospital. All these patients were treated successfully with TCE and had factors other then TCE contributing to their mortality. Conclusion: Transcatheter embolisation for vascular injuries was found to be a satisfactory procedure, with low morbidity and mortality rates. (author)

  13. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance a2+-activated K+ channels

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-01-01

    Background and Purpose Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. Experimental Approach The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). Key Results At a concentration without direct effect on vascular tone, kaempferol (3 × 10−6 M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by Nω-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10−4 M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10−6 M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10−3 M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa1.1; 10−7 M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. Conclusions and Implications The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa1.1 channels. PMID:25652142

  14. Multinephron dynamics on the renal vascular network

    DEFF Research Database (Denmark)

    Marsh, Donald J; Wexler, Anthony S; Brazhe, Alexey

    2012-01-01

    Tubuloglomerular feedback (TGF) and the myogenic mechanism combine in each nephron to regulate blood flow and glomerular filtration rate. Both mechanisms are non-linear, generate self-sustained oscillations, and interact as their signals converge on arteriolar smooth muscle, forming a regulatory...... clusters. In-phase synchronization predominated among nephrons separated by 1 or 3 vascular nodes, and anti-phase synchronization for 5 or 7 nodes of separation. Nephron dynamics were irregular and contained low frequency fluctuations. Results are consistent with simultaneous blood flow measurements...... of both mechanisms in the regulatory ensemble, to examine the effects of network structure on nephron synchronization. Symmetry, as a property of a network, facilitates synchronization. Nephrons received blood from a symmetric electrically conductive vascular tree. Symmetry was created by using identical...

  15. Vascular lesions of the vocal fold.

    Science.gov (United States)

    Gökcan, Kürşat Mustafa; Dursun, Gürsel

    2009-04-01

    The aim of the study was to present symptoms, laryngological findings, clinical course, management modalities, and consequences of vascular lesions of vocal fold. This study examined 162 patients, the majority professional voice users, with vascular lesions regarding their presenting symptoms, laryngological findings, clinical courses and treatment results. The most common complaint was sudden hoarseness with hemorrhagic polyp. Microlaryngoscopic surgery was performed in 108 cases and the main indication of surgery was the presence of vocal fold mass or development of vocal polyp during clinical course. Cold microsurgery was utilized for removal of vocal fold masses and feeding vessels cauterized using low power, pulsed CO(2) laser. Acoustic analysis of patients revealed a significant improvement of jitter, shimmer and harmonics/noise ratio values after treatment. Depending on our clinical findings, we propose treatment algorithm where voice rest and behavioral therapy is the integral part and indications of surgery are individualized for each patient.

  16. Clinical applications of robotic technology in vascular and endovascular surgery.

    Science.gov (United States)

    Antoniou, George A; Riga, Celia V; Mayer, Erik K; Cheshire, Nicholas J W; Bicknell, Colin D

    2011-02-01

    Emerging robotic technologies are increasingly being used by surgical disciplines to facilitate and improve performance of minimally invasive surgery. Robot-assisted intervention has recently been introduced into the field of vascular surgery to potentially enhance laparoscopic vascular and endovascular capabilities. The objective of this study was to review the current status of clinical robotic applications in vascular surgery. A systematic literature search was performed in order to identify all published clinical studies related to robotic implementation in vascular intervention. Web-based search engines were searched using the keywords "surgical robotics," "robotic surgery," "robotics," "computer assisted surgery," and "vascular surgery" or "endovascular" for articles published between January 1990 and November 2009. An evaluation and critical overview of these studies is reported. In addition, an analysis and discussion of supporting evidence for robotic computer-enhanced telemanipulation systems in relation to their applications in laparoscopic vascular and endovascular surgery was undertaken. Seventeen articles reporting on clinical applications of robotics in laparoscopic vascular and endovascular surgery were detected. They were either case reports or retrospective patient series and prospective studies reporting laparoscopic vascular and endovascular treatments for patients using robotic technology. Minimal comparative clinical evidence to evaluate the advantages of robot-assisted vascular procedures was identified. Robot-assisted laparoscopic aortic procedures have been reported by several studies with satisfactory results. Furthermore, the use of robotic technology as a sole modality for abdominal aortic aneurysm repair and expansion of its applications to splenic and renal artery aneurysm reconstruction have been described. Robotically steerable endovascular catheter systems have potential advantages over conventional catheterization systems

  17. Pancreatic transplantation: Radiologic evaluation of vascular complications

    International Nuclear Information System (INIS)

    Snider, J.F.; Hunter, D.W.; Kuni, C.C.; Castaneda-Zuniga, W.R.; Letourneau, J.G.

    1991-01-01

    Transplantation of the pancreas is an increasingly common therapeutic option for preventing or delaying complications of type I diabetes mellitus. The authors studied the relative roles of various radiologic examinations in diagnosing vascular complications in these grafts including arterial and venous thrombosis, stenosis, and anastomotic leak (the most common vascular factors that necessitate pancreatectomy of the transplant), as defined with pathologic or arteriographic data. The results of 78 scintigraphic flow studies, 40 abdominal and pelvic computed tomographic (CT) scans, 27 sonograms, and eight color Doppler studies were evaluated in 52 patients who received a total of 27 cadaveric and 26 living-donor grafts over a 12-year period. These results were correlated with the data from 45 gross and microscopic pathologic studies and 37 arteriograms to determine their relative value in enabling detection of graft thrombosis and other vascular complications. Scintigraphy, CT, sonography, and color Doppler were all sensitive in detection of generalized graft abnormalities but lacked specificity in defining the underlying etiologic factors

  18. Pancreatic transplantation: Radiologic evaluation of vascular complications

    Energy Technology Data Exchange (ETDEWEB)

    Snider, J.F.; Hunter, D.W.; Kuni, C.C.; Castaneda-Zuniga, W.R.; Letourneau, J.G. (Univ. of Minnesota Hospital and Clinic, Minneapolis (USA))

    1991-03-01

    Transplantation of the pancreas is an increasingly common therapeutic option for preventing or delaying complications of type I diabetes mellitus. The authors studied the relative roles of various radiologic examinations in diagnosing vascular complications in these grafts including arterial and venous thrombosis, stenosis, and anastomotic leak (the most common vascular factors that necessitate pancreatectomy of the transplant), as defined with pathologic or arteriographic data. The results of 78 scintigraphic flow studies, 40 abdominal and pelvic computed tomographic (CT) scans, 27 sonograms, and eight color Doppler studies were evaluated in 52 patients who received a total of 27 cadaveric and 26 living-donor grafts over a 12-year period. These results were correlated with the data from 45 gross and microscopic pathologic studies and 37 arteriograms to determine their relative value in enabling detection of graft thrombosis and other vascular complications. Scintigraphy, CT, sonography, and color Doppler were all sensitive in detection of generalized graft abnormalities but lacked specificity in defining the underlying etiologic factors.

  19. A microfluidic device for study of the effect of tumor vascular structures on the flow field and HepG2 cellular flow behaviors.

    Science.gov (United States)

    Ke, Ming; Cai, Shaoxi; Zou, Misha; Zhao, Yi; Li, Bo; Chen, Sijia; Chen, Longcong

    2018-01-29

    To build a microfluidic device with various morphological features of the tumor vasculature for study of the effects of tumor vascular structures on the flow field and tumor cellular flow behaviors. The designed microfluidic device was able to approximatively simulate the in vivo structures of tumor vessels and the flow within it. In this models, the influences of the angle of bifurcation, the number of branches, and the narrow channels on the flow field and the influence of vorticity on the retention of HepG2 cells were significant. Additionally, shear stress below physiological conditions of blood circulation has considerable effect on the formation of the lumen-like structures (LLSs) of HepG2 cells. These results can provide some data and reference in the understanding of the interaction between hemorheological properties and tumor vascular structures in solid tumors. Copyright © 2018. Published by Elsevier Inc.

  20. Plasma channels for electron beam transport

    International Nuclear Information System (INIS)

    Schneider, R.F.; Smith, J.R.; Moffatt, M.E.; Nguyen, K.T.; Uhm, H.S.

    1988-01-01

    In recent years, there has been much interest in transport of intense relativistic electron beams using plasma channels. These channels are formed by either: ionization of an organic gas by UV photoionization or electron impact ionization of a low pressure gas utilizing a low energy (typically several hundred volts) electron gun. The second method is discussed here. As their electron gun, the authors used a 12 volt lightbulb filament which is biased to -400 volts with respect to the grounded 15 cm diameter drift tube. The electrons emitted from the filament are confined by an axial magnetic field of --100 Gauss to create a plasma channel which is less than 1 cm in radius. The channel density has been determined with Langmuir probes and the resulting line densities were found to be 10 11 to 10 12 per cm. When a multi-kiloamp electron beam is injected onto this channel, the beam space charge will eject the plasma electrons leaving the ions behind to charge neutralize the electron beam, hence allowing the beam to propagate. In this work, the authors performed experimental studies on the dynamics of the plasma channel. These include Langmuir probe measurements of a steady state (DC) channel, as well as time-resolved Langmuir probe studies of pulsed channels. In addition they performed experimental studies of beam propagation in these plasma channels. Specifically, they observed the behavior of current transport in these channels. Detailed results of beam transport and channel studies are presented

  1. Role of vascular physiology in hyperthermia

    International Nuclear Information System (INIS)

    Song, C.W.

    1987-01-01

    The rate of blood supply to tumors significantly varies depending on the tumor type, site of tumor growth, and the stage of tumor growth. Even in the same tumor, blood flow is rather heterogeneous. The peripheral area of the tumors where the tissue pressure is relatively low is usually well perfused. Blood flow in the tumors may or may not be greater than that in the adjacent normal tissues. The response of newly formed tumor blood vessels to external stress, such as heat, it different from that in the normal tissues. Blood flow in the experimental rodent tumors initially increases up to twofold of control when heated at relatively low temperatures but tends to decrease when heated at temperatures above 42 0 -43 0 C. On the contrary, blood flow in the skin and muscle of rodents increases up to 20-fold before vascular damage occurs on heating at 43 0 -45 0 C. It thus appears that the vascular beds in tumors are more vulnerable to heat than those in normal tissues. Because of the large increase in blood flow in normal tissue on heating, heat dissipation by blood flow is usually greater in normal tissues than that in tumors during heating. Consequently, the temperature of tumors may rise higher than that in normal tissues. Preferential heating of tumors, however, may not be achieved all the time because the relative blood perfusion in some tumors or in parts of a tumor remains greater than that in the surrounding normal tissues. The intrinsically acidic intratumor environment becomes further acidic on heating owing to an increase in the synthesis of acidic metabolites and retarded removal of them as a result of heat-induced vascular damage. The intratumor environment also becomes hypoxic as a result of retardation of blood flow and vascular damage after heating

  2. Pediatric interventional radiology: vascular interventions

    International Nuclear Information System (INIS)

    Kandasamy, Devasenathipathy; Gamanagatti, Shivanand; Gupta, Arun Kumar

    2016-01-01

    Pediatric interventional radiology (PIR) comprises a range of minimally invasive diagnostic and therapeutic procedures that are performed using image guidance. PIR has emerged as an essential adjunct to various surgical and medical conditions. Over the years, technology has undergone dramatic and continuous evolution, making this speciality grow. In this review, the authors will discuss various vascular interventional procedures undertaken in pediatric patients. It is challenging for the interventional radiologist to accomplish a successful interventional procedure. There are many vascular interventional radiology procedures which are being performed and have changed the way the diseases are managed. Some of the procedures are life saving and have become the treatment of choice in those patients. The future is indeed bright for the practice and practitioners of pediatric vascular and non-vascular interventions. As more and more of the procedures that are currently being performed in adults get gradually adapted for use in the pediatric population, it may be possible to perform safe and successful interventions in many of the pediatric vascular lesions that are otherwise being referred for surgery. (author)

  3. An information-guided channel-hopping scheme for block-fading channels with estimation errors

    KAUST Repository

    Yang, Yuli

    2010-12-01

    Information-guided channel-hopping technique employing multiple transmit antennas was previously proposed for supporting high data rate transmission over fading channels. This scheme achieves higher data rates than some mature schemes, such as the well-known cyclic transmit antenna selection and space-time block coding, by exploiting the independence character of multiple channels, which effectively results in having an additional information transmitting channel. Moreover, maximum likelihood decoding may be performed by simply decoupling the signals conveyed by the different mapping methods. In this paper, we investigate the achievable spectral efficiency of this scheme in the case of having channel estimation errors, with optimum pilot overhead for minimum meansquare error channel estimation, when transmitting over blockfading channels. Our numerical results further substantiate the robustness of the presented scheme, even with imperfect channel state information. ©2010 IEEE.

  4. The diabetic foot - modern possibilities of vascular reconstruction

    International Nuclear Information System (INIS)

    Arlart, I.P.

    1992-01-01

    Arterial vascular disease in diabetic patients includes both microangiopathy and macroangiopathy. Macroangiopathy, i.e. stenoses of occlusions of the ilio-femoro-popliteal arteries and crural arteries, can be treated by surgical vascular reconstructions and radiological procedures such as recanalisation via catheter and CT-guided lumbar sympathetic trunk, neurolysis. In this paper the different therapeutic techniques are presented in respect of indications and results particularly in the diabetic patients. (orig.) [de

  5. Brain Arterial Diameters as a Risk Factor for Vascular Events

    OpenAIRE

    Gutierrez, Jose; Cheung, Ken; Bagci, Ahmet; Rundek, Tatjana; Alperin, Noam; Sacco, Ralph L; Wright, Clinton B; Elkind, Mitchell S V

    2015-01-01

    Background Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events. Methods and Results Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, ca...

  6. Vascular Function at Baseline in the Hemodialysis Fistula Maturation Study

    OpenAIRE

    Dember, Laura M.; Imrey, Peter B.; Duess, Mai?Ann; Hamburg, Naomi M.; Larive, Brett; Radeva, Milena; Himmelfarb, Jonathan; Kraiss, Larry W.; Kusek, John W.; Roy?Chaudhury, Prabir; Terry, Christi M.; Vazquez, Miguel A.; Vongpatanasin, Wanpen; Beck, Gerald J.; Vita, Joseph A.

    2016-01-01

    Background End?stage renal disease is accompanied by functional and structural vascular abnormalities. The objective of this study was to characterize vascular function in a large cohort of patients with end?stage renal disease, using noninvasive physiological measurements, and to correlate function with demographic and clinical factors. Methods and Results We analyzed cross?sectional baseline data from the Hemodialysis Fistula Maturation Study, a multicenter prospective observational cohort ...

  7. Ruthenium Complexes as NO Donors for Vascular Relaxation Induction

    Directory of Open Access Journals (Sweden)

    Renata Galvão de Lima

    2014-07-01

    Full Text Available Nitric oxide (NO donors are substances that can release NO. Vascular relaxation induction is among the several functions of NO, and the administration of NO donors is a pharmacological alternative to treat hypertension. This review will focus on the physicochemical description of ruthenium-derived NO donor complexes that release NO via reduction and light stimulation. In particular, we will discuss the complexes synthesized by our research group over the last ten years, and we will focus on the vasodilation and arterial pressure control elicited by these complexes. Soluble guanylyl cyclase (sGC and potassium channels are the main targets of the NO species released from the inorganic compounds. We will consider the importance of the chemical structure of the ruthenium complexes and their vascular effects.

  8. Secure Broadcasting with Uncertain Channel State Information

    KAUST Repository

    Hyadi, Amal; Rezki, Zouheir; Khisti, Ashish; Alouini, Mohamed-Slim

    2017-01-01

    -main CSI are also analyzed. Analytical derivations and numerical results are presented to illustrate the obtained expressions for the case of independent and identically distributed Rayleigh fading channels.

  9. Secure Broadcasting with Uncertain Channel State Information

    KAUST Repository

    Hyadi, Amal; Rezki, Zouheir; Khisti, Ashish; Alouini, Mohamed-Slim

    2016-01-01

    -main CSI are also analyzed. Analytical derivations and numerical results are presented to illustrate the obtained expressions for the case of independent and identically distributed Rayleigh fading channels.

  10. Channel selection for automatic seizure detection

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas; Kjaer, Troels Wesenberg; Madsen, Rasmus Elsborg

    2012-01-01

    Objective: To investigate the performance of epileptic seizure detection using only a few of the recorded EEG channels and the ability of software to select these channels compared with a neurophysiologist. Methods: Fifty-nine seizures and 1419 h of interictal EEG are used for training and testing...... of an automatic channel selection method. The characteristics of the seizures are extracted by the use of a wavelet analysis and classified by a support vector machine. The best channel selection method is based upon maximum variance during the seizure. Results: Using only three channels, a seizure detection...... sensitivity of 96% and a false detection rate of 0.14/h were obtained. This corresponds to the performance obtained when channels are selected through visual inspection by a clinical neurophysiologist, and constitutes a 4% improvement in sensitivity compared to seizure detection using channels recorded...

  11. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

  12. On the Capacity of the Dirty Paper Channel with Fast Fading and Discrete Channel States

    OpenAIRE

    Rini, Stefano; Shitz, Shlomo Shamai

    2016-01-01

    The "writing dirty paper" capacity result crucially dependents on the perfect channel knowledge at the transmitter as the presence of even a small uncertainty in the channel realization gravely hampers the ability of the transmitter to pre-code its transmission against the channel state. This is particularly disappointing as it implies that interference pre-coding in practical systems is effective only when the channel estimates at the users have very high precision, a condition which is gene...

  13. Fetal origin of vascular aging

    Directory of Open Access Journals (Sweden)

    Shailesh Pitale

    2011-01-01

    Full Text Available Aging is increasingly regarded as an independent risk factor for development of cardiovascular diseases such as atherosclerosis and hypertension and their complications (e.g. MI and Stroke. It is well known that vascular disease evolve over decades with progressive accumulation of cellular and extracellular materials and many inflammatory processes. Metabolic syndrome, obesity and diabetes are conventionally recognized as risk factors for development of coronary vascular disease (CVD. These conditions are known to accelerate ageing process in general and vascular ageing in particular. Adverse events during intrauterine life may programme organ growth and favour disease later in life, popularly known as, ′Barker′s Hypothesis′. The notion of fetal programming implies that during critical periods of prenatal growth, changes in the hormonal and nutritional milieu of the conceptus may alter the full expression of the fetal genome, leading to permanent effects on a range of physiological.

  14. Imaging after vascular gene therapy

    International Nuclear Information System (INIS)

    Manninen, Hannu I.; Yang, Xiaoming

    2005-01-01

    Targets for cardiovascular gene therapy currently include limiting restenosis after balloon angioplasty and stent placement, inhibiting vein bypass graft intimal hyperplasia/stenosis, therapeutic angiogenesis for cardiac and lower-limb ischemia, and prevention of thrombus formation. While catheter angiography is still standard method to follow-up vascular gene transfer, other modern imaging techniques, especially intravascular ultrasound (IVUS), magnetic resonance (MR), and positron emission tomography (PET) imaging provide complementary information about the therapeutic effect of vascular gene transfer in humans. Although molecular imaging of therapeutic gene expression in the vasculatures is still in its technical development phase, it has already offered basic medical science an extremely useful in vivo evaluation tool for non- or minimally invasive imaging of vascular gene therapy

  15. USACE Navigation Channels 2012

    Data.gov (United States)

    California Natural Resource Agency — This dataset represents both San Francisco and Los Angeles District navigation channel lines. All San Francisco District channel lines were digitized from CAD files...

  16. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium-channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium-channel blockers are a type of medicine used ...

  17. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance Ca(2+) -activated K(+) channels.

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-06-01

    Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). At a concentration without direct effect on vascular tone, kaempferol (3 × 10(-6) M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by N(ω)-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10(-4) M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10(-6) M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10(-3) M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa 1.1; 10(-7) M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa 1.1 channels. © 2015 The British Pharmacological Society.

  18. Vascular Dysfunction in Horses with Endocrinopathic Laminitis.

    Directory of Open Access Journals (Sweden)

    Ruth A Morgan

    Full Text Available Endocrinopathic laminitis (EL is a vascular condition of the equine hoof resulting in severe lameness with both welfare and economic implications. EL occurs in association with equine metabolic syndrome and equine Cushing's disease. Vascular dysfunction, most commonly due to endothelial dysfunction, is associated with cardiovascular risk in people with metabolic syndrome and Cushing's syndrome. We tested the hypothesis that horses with EL have vascular, specifically endothelial, dysfunction. Healthy horses (n = 6 and horses with EL (n = 6 destined for euthanasia were recruited. We studied vessels from the hooves (laminar artery, laminar vein and the facial skin (facial skin arteries by small vessel wire myography. The response to vasoconstrictors phenylephrine (10-9-10-5M and 5-hydroxytryptamine (5HT; 10-9-10-5M and the vasodilator acetylcholine (10-9-10-5M was determined. In comparison with healthy controls, acetylcholine-induced relaxation was dramatically reduced in all intact vessels from horses with EL (% relaxation of healthy laminar arteries 323.5 ± 94.1% v EL 90.8 ± 4.4%, P = 0.01, laminar veins 129.4 ± 14.8% v EL 71.2 ± 4.1%, P = 0.005 and facial skin arteries 182.0 ± 40.7% v EL 91.4 ± 4.5%, P = 0.01. In addition, contractile responses to phenylephrine and 5HT were increased in intact laminar veins from horses with EL compared with healthy horses; these differences were endothelium-independent. Sensitivity to phenylephrine was reduced in intact laminar arteries (P = 0.006 and veins (P = 0.009 from horses with EL. Horses with EL exhibit significant vascular dysfunction in laminar vessels and in facial skin arteries. The systemic nature of the abnormalities suggest this dysfunction is associated with the underlying endocrinopathy and not local changes to the hoof.

  19. VASCULAR REMODELING IN HYPERTENSION: ANGIOGENESIS FEATURES

    Directory of Open Access Journals (Sweden)

    L. A. Haisheva

    2014-07-01

    Full Text Available Aim — cross-sectional study of changes in various segments of the vascular bed in arterial hypertension (AH, defining the role of inducers and inhibitors of angiogenesis in these processes.Materials and methods. The study included 99 patients with arterial hypertension of I–II degree, average age of 63.2 ± 2.6 years, diseaseduration 9.2 ± 7.2 years.Results. It was found that patients with arterial hypertension have disorders in all segments of vascular bed: endothelial dysfunction (highvWF, microcirculatory disorders, and increased pulse wave velocity (PWV of elastic-type vessels. The level of angioginesis factors doesnot depend on such parameters as gender, age, body mass index. Smoking and duration of hypertension influence on vascular endothelialgrowth factor raise and endostatin levels are higher in patients with family history of cardiovascular diseases. Duration of disease is directlycorrelated with microcirculatory disorders and the PWV, correlation between microcirculatory disorders and pulse wave velocity indicatetheir common processes.

  20. Amplatzer vascular plugs in congenital cardiovascular malformations

    International Nuclear Information System (INIS)

    Barwad, Parag; Ramakrishnan, Sivasubramanian; Kothari, Shyam S; Saxena, Anita; Gupta, Saurabh K; Juneja, Rajnish; Gulati, Gurpreet Singh; Jagia, Priya; Sharma, Sanjiv

    2013-01-01

    Amplatzer vascular plugs (AVPs) are devices ideally suited to close medium-to-large vascular communications. There is limited published literature regarding the utility of AVPs in congenital cardiovascular malformations (CCVMs). To describe the use of AVPs in different CCVMs and to evaluate their safety and efficacy. All patients who required an AVP for the closure of CCVM were included in this retrospective review of our catheterization laboratory data. The efficacy and safety of AVPs are reported. A total of 39 AVPs were implanted in 31 patients. Thirteen (33%) were AVP type I and 23 (59%) were AVP type II. AVP type III were implanted in two patients and type IV in one patient. The major indications for their use included closure of pulmonary arteriovenous malformation (AVM) (n = 7), aortopulmonary collaterals (n = 7), closure of a patent Blalock-Taussig shunt (n = 5), systemic AVM (n = 5), coronary AVM (n = 4), patent ductus arteriosus (PDA) (n = 3), pulmonary artery aneurysms (n = 3), and venovenous collaterals (n = 2). Deployment of the AVP was done predominantly via the 5 – 7F Judkin's right coronary guide catheter. Overall 92% of the AVPs could be successfully deployed and resulted in occlusion of the target vessel in all cases, within 10 minutes. No procedure-related or access site complication occurred. AVPs are versatile, easy to use, and effective devices to occlude the vascular communications in a variety of settings. AVP II is especially useful in the closure of tubular structures with a high flow

  1. Vascular development in the vertebrate pancreas

    Science.gov (United States)

    Azizoglu, D. Berfin; Chong, Diana C.; Villasenor, Alethia; Magenheim, Judith; Barry, David M.; Lee, Simon; Marty-Santos, Leilani; Fu, Stephen; Dor, Yuval; Cleaver, Ondine

    2016-01-01

    The vertebrate pancreas is comprised of a highly branched tubular epithelium, which is intimately associated with an extensive and specialized vasculature. While we know a great deal about basic vascular anatomy of the adult pancreas, as well as islet capillaries, surprisingly little is known about the ontogeny of its blood vessels. Here, we analyze development of the pancreatic vasculature in the mouse embryo. We show that pancreatic epithelial branches intercalate with the fine capillary plexus of the surrounding pancreatic mesenchyme. Endothelial cells (ECs) within this mesenchyme are heterogeneous from the onset of organogenesis. Pancreatic arteries take shape before veins, in a manner analogous to early embryonic vessels. The main central artery forms during mid-gestation, as a result of vessel coalescence and remodeling of a vascular plexus. In addition, we show that vessels in the forming pancreas display a predictable architecture that is dependent on VEGF signaling. Over-expression of VEGF disrupts vascular patterning and arteriovenous differentiation within the developing pancreas. This study constitutes a first-time cellular and molecular characterization of pancreatic blood vessels, as they coordinately grow along with the pancreatic epithelium. PMID:27789228

  2. Vascularized nerve grafts: an experimental study.

    Science.gov (United States)

    Donzelli, Renato; Capone, Crescenzo; Sgulò, Francesco Giovanni; Mariniello, Giuseppe; Maiuri, Francesco

    2016-08-01

    The aim of this study is to define an experimental model in order to promote the functional recovery of the nerves using grafts with vascular support (Vascular Nerve Grafts - VNG). The aim of this study is to define, on an experimental model in normal recipient bed, whether the functional recovery with VNG is superior to that obtained non-vascularized graft (NNG). Twenty male rabbits, which underwent dissection of sciatic nerve, were later treated by reinnervation through an autograft. In 10 animals the reconstruction of sciatic nerve was realized with VNG; in 10 control animals the reconstruction of sciatic nerve was realized with NNG. The VNG group showed a better axonal organization and a significantly higher number of regenerated axons in the early phases (after 30 days) than the NNG group, whereas the difference in the axonal number at day 90 was less significant; besides, the axon diameter and the myelin thickness were not significantly improved by VNG group. Our data suggests that the use of VNG leads to a faster regeneration process and a better functional recovery, although the final results are comparable to those of the NNG. VNG improve the quality of the axonal regeneration (axonal diameter and Schwann cells), although the increase in the axonal number is not significant and does not improve the long-term functional outcome.

  3. Vascular development in the vertebrate pancreas.

    Science.gov (United States)

    Azizoglu, D Berfin; Chong, Diana C; Villasenor, Alethia; Magenheim, Judith; Barry, David M; Lee, Simon; Marty-Santos, Leilani; Fu, Stephen; Dor, Yuval; Cleaver, Ondine

    2016-12-01

    The vertebrate pancreas is comprised of a highly branched tubular epithelium, which is intimately associated with an extensive and specialized vasculature. While we know a great deal about basic vascular anatomy of the adult pancreas, as well as islet capillaries, surprisingly little is known about the ontogeny of its blood vessels. Here, we analyze development of the pancreatic vasculature in the mouse embryo. We show that pancreatic epithelial branches intercalate with the fine capillary plexus of the surrounding pancreatic mesenchyme. Endothelial cells (ECs) within this mesenchyme are heterogeneous from the onset of organogenesis. Pancreatic arteries take shape before veins, in a manner analogous to early embryonic vessels. The main central artery forms during mid-gestation, as a result of vessel coalescence and remodeling of a vascular plexus. In addition, we show that vessels in the forming pancreas display a predictable architecture that is dependent on VEGF signaling. Over-expression of VEGF disrupts vascular patterning and arteriovenous differentiation within the developing pancreas. This study constitutes a first-time in-depth cellular and molecular characterization of pancreatic blood vessels, as they coordinately grow along with the pancreatic epithelium. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Le cône sous-marin du Nil et son réseau de chenaux profonds : nouveaux résultats (campagne Fanil)The Nile Cone and its channel system: new results after the Fanil cruise

    Science.gov (United States)

    Bellaiche, Gilbert; Loncke, Lies; Gaullier, Virginie; Mascle, Jean; Courp, Thierry; Moreau, Alain; Radan, Silviu; Sardou, Olivier

    2001-10-01

    The meandrous leveed channels of the Nile Cone show clear evidence of avulsions. Their sedimentary architecture is founded on numerous stacked lens-shaped acoustic units. In the areas of the distal fan, lobe deposits are apparent from multichannel imagery. Huge debris flow deposits, sometimes associated with pockmarks, are recognized. Mud volcanoes and gas seeping are closely associated with faulting. In the East, a very long north-trending channel, originating from the Egyptian coast, merges with a network of channels, very probably originating from the Levantine coasts. Both networks outlet in the sedimentary basin located south of Cyprus.

  5. Bone Marrow Vascular Niche: Home for Hematopoietic Stem Cells

    Directory of Open Access Journals (Sweden)

    Ningning He

    2014-01-01

    Full Text Available Though discovered later than osteoblastic niche, vascular niche has been regarded as an alternative indispensable niche operating regulation on hematopoietic stem cells (HSCs. As significant progresses gained on this type niche, it is gradually clear that the main work of vascular niche is undertaking to support hematopoiesis. However, compared to what have been defined in the mechanisms through which the osteoblastic niche regulates hematopoiesis, we know less in vascular niche. In this review, based on research data hitherto we will focus on component foundation and various functions of vascular niche that guarantee the normal hematopoiesis process within bone marrow microenvironments. And the possible pathways raised by various research results through which this environment undergoes its function will be discussed as well.

  6. Nitric oxide signaling and the cross talk with prostanoids pathways in vascular system.

    Science.gov (United States)

    Silva, Bruno R; Paula, Tiago D; Paulo, Michele; Bendhack, Lusiane M

    2016-12-28

    This review provides an overview of the cellular signaling of nitric oxide (NO) and prostanoids in vascular cells and the possible cross talk between their pathways, mainly in hypertension, since the imbalance of these two systems has been attributed to development of some cardiovascular diseases. It also deals with the modulation of vasodilation induced by NO donors. NO is a well-known second messenger involved in many cellular functions. In the vascular system, the NO produced by endothelial NO-synthase (eNOS) or released by NO donors acts in vascular smooth muscle cells, the binding of NO to Fe2+-heme of soluble guanylyl-cyclase (sGC) activates sGC and the production of cyclic guanosine-3-5-monophosphate (cGMP). The second messenger (cGMP) activates protein kinase G and the signaling cascade, including K+ channels. Activation of K+ channels leads to cell membrane hyperpolarization and Ca2+ channels blockade, which induce vascular relaxation. Moreover, the enzyme cyclooxygenase (COX) is also an important regulator of the vascular function by prostanoids production such as thromboxane A2 (TXA2) and prostacyclin (PGI2), which classically induce contraction and relaxation, respectively. Additionaly, studies indicate that the activity of both enzymes can be modulated by their products and reactive oxygen species (ROS) in cardiovascular diseases such as hypertension. The interaction of NO with cellular molecules, particularly the reaction of NO with ROS, determines the biological mechanisms of action and short half-life of NO. We have been working on the vascular effects of ruthenium-derived complexes that release NO. Our research group has published works on the vasodilating effects of ruthenium-derived NO donors and the mechanisms of vascular cells involved in the relaxation of the vascular smooth muscle in health and hypertensive rats. In our previous studies, we have compared the new NO donors synthesized by our group to SNP. It shows the cellular signaling of NO

  7. In vivo quantitative evaluation of vascular parameters for angiogenesis based on sparse principal component analysis and aggregated boosted trees

    International Nuclear Information System (INIS)

    Zhao, Fengjun; Liu, Junting; Qu, Xiaochao; Xu, Xianhui; Chen, Xueli; Yang, Xiang; Liang, Jimin; Tian, Jie; Cao, Feng

    2014-01-01

    To solve the multicollinearity issue and unequal contribution of vascular parameters for the quantification of angiogenesis, we developed a quantification evaluation method of vascular parameters for angiogenesis based on in vivo micro-CT imaging of hindlimb ischemic model mice. Taking vascular volume as the ground truth parameter, nine vascular parameters were first assembled into sparse principal components (PCs) to reduce the multicolinearity issue. Aggregated boosted trees (ABTs) were then employed to analyze the importance of vascular parameters for the quantification of angiogenesis via the loadings of sparse PCs. The results demonstrated that vascular volume was mainly characterized by vascular area, vascular junction, connectivity density, segment number and vascular length, which indicated they were the key vascular parameters for the quantification of angiogenesis. The proposed quantitative evaluation method was compared with both the ABTs directly using the nine vascular parameters and Pearson correlation, which were consistent. In contrast to the ABTs directly using the vascular parameters, the proposed method can select all the key vascular parameters simultaneously, because all the key vascular parameters were assembled into the sparse PCs with the highest relative importance. (paper)

  8. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Role of vascular smooth muscle cells in vascular calcification].

    Science.gov (United States)

    Kurabayashi, Masahiko

    2015-05-01

    Vascular calcification is commonly seen with aging, chronic kidney disese (CKD), diabetes, and atherosclerosis, and is closely associated with cardiovascular morbidity and mortality. Vascular calcification has long been regarded as the final stage of degeneration and necrosis of arterial wall and a passive, unregulated process. However, it is now known to be an active and tightly regulated process involved with phenotypic transition of vascular smooth muscle cells (VSMC) that resembles bone mineralization. Briefly, calcium deposits of atherosclerotic plaque consist of hydroxyapatite and may appear identical to fully formed lamellar bone. By using a genetic fate mapping strategy, VSMC of the vascular media give rise to the majority of the osteochondrogenic precursor- and chondrocyte-like cells observed in the calcified arterial media of MGP (- / -) mice. Osteogenic differentiation of VSMC is characterized by the expression of bone-related molecules including bone morphogenetic protein (BMP) -2, Msx2 and osteopontin, which are produced by osteoblasts and chondrocytes. Our recent findings are that (i) Runx2 and Notch1 induce osteogenic differentiation, and (ii) advanced glycation end-product (AGE) /receptor for AGE (RAGE) and palmitic acid promote osteogenic differentiation of VSMC. To understand of the molecular mechanisms of vascular calcification is now under intensive research area.

  9. Channel perceptions and usage: beyond media richness factors

    NARCIS (Netherlands)

    Pieterson, Willem Jan; Teerling, Marije; Ebbers, Wolfgang E.; Wimmer, Maria A.; Scholl, Hans J.; Ferro, Enrico

    2008-01-01

    In this paper, we asses how service channel perceptions affect channel choice and channel usage. Building on communication theories, such as the Media Richness Theory, we explore how different channel characteristics are perceived by citizens in a Dutch governmental service chain. The results of our

  10. Vascular malforma- tions part 1 — normal and abnormal vascular ...

    African Journals Online (AJOL)

    Enrique

    to form the primitive vascular plexus. Angiogenesis is the formation of new vessels by sprouting or splitting of ... The differentiation of primitive vessels into arteries, veins or capillaries is determined by flow patterns .... identify, but it is probable that as time progresses further specific genetic defects related to the development ...

  11. Genetic Regulation of Vascular Development: Building the Zebrafish Vascular Tree

    NARCIS (Netherlands)

    R.L.J.M. Herpers (Robert)

    2010-01-01

    textabstractThe extensive networks of blood and lymphatic vessels within the vertebrate body are essential for the transport and delivery of fluids, gases, macromolecules and cells, and play important roles in facilitating immune responses. The development of the vascular tree requires a highly

  12. Quantum Channels With Memory

    International Nuclear Information System (INIS)

    Rybar, T.

    2012-01-01

    Quantum memory channels represent a very general, yet simple and comprehensible model for causal processes. As such they have attracted considerable research interest, mostly aimed on their transfer capabilities and structure properties. Most notably it was shown that memory channels can be implemented via physically naturally motivated collision models. We also define the concept of repeatable channels and show that only unital channels can be implemented repeat ably with pure memory channels. In the special case of qubit channels we also show that every unital qubit channel has a repeatable implementation. We also briefly explore the possibilities of stroboscopical simulation of channels and show that all random unitary channels can be stroboscopically simulated. Particularly in qubit case, all indivisible qubit channels are also random unitary, hence for qubit all indivisible channels can be stroboscopically simulated. Memory channels also naturally capture the framework of correlated experiments. We develop methods to gather and interpret data obtained in such setting and in detail examine the two qubit case. We also show that for control unitary interactions the measured data will never contradict a simple unitary evolution. Thus no memory effects can be spotted then. (author)

  13. Hsc70 regulates cell surface ASIC2 expression and vascular smooth muscle cell migration.

    Science.gov (United States)

    Grifoni, Samira C; McKey, Susan E; Drummond, Heather A

    2008-05-01

    Recent studies suggest members of the degenerin (DEG)/epithelial Na(+) channel (ENaC)/acid-sensing ion channel (ASIC) protein family play an important role in vascular smooth muscle cell (VSMC) migration. In a previous investigation, we found suppression of a certain DEG/ENaC/ASIC member, ASIC2, increased VSMC chemotactic migration, raising the possibility that ASIC2 may play an inhibitory role. Because ASIC2 protein was retained in the cytoplasm, we reasoned increasing surface expression of ASIC2 might unmask the inhibitory role of ASIC2 in VSMC migration so we could test the hypothesis that ASIC2 inhibits VSMC migration. Therefore, we used the chemical chaperone glycerol to enhance ASIC2 expression. Glycerol 1) increased cytoplasm ASIC2 expression, 2) permitted detection of ASIC2 at the cell surface, and 3) inhibited platelet-derived growth factor (PDGF)-bb mediated VSMC migration. Furthermore, ASIC2 silencing completely abolished the inhibitory effect of glycerol on migration, suggesting upregulation of ASIC2 is responsible for glycerol-induced inhibition of VSMC migration. Because other investigators have shown that glycerol regulates ENaC/ASIC via interactions with a certain heat shock protein, heat shock protein 70 (Hsc70), we wanted to determine the importance of Hsc70 on ASIC2 expression in VSMCs. We found that Hsc70 silencing increases ASIC2 cell surface expression and inhibits VSMC migration, which is abolished by cosilencing ASIC2. These data demonstrate that Hsc70 inhibits ASIC2 expression, and, when the inhibitory effect of Hsc70 is removed, ASIC2 expression increases, resulting in reduced VSMC migration. Because VSMC migration contributes to vasculogenesis and remodeling following vascular injury, our findings raise the possibility that ASIC2-Hsc70 interactions may play a role in these processes.

  14. [Synopsis about the hypothesis of "information channel" of channel-collateral system].

    Science.gov (United States)

    Chang, Xi-Lang

    2008-10-01

    The author of the present paper founded a theorem about the "incompleteness of single channel structure" (nerve, blood vessel, lymphatic, interspace, aperture, etc.) through quantitative and qualitative analysis about the economic information channel in the human body, which eliminates the probability of single channel structure in the information channel of channel (meridian)-collateral system. After comprehensive analysis on the current researches, the author puts forward a neodoxy, i.e., the body "information channel" structure of the channel-collateral system, mainly follows the distribution regularity of systemic statistics, and is not a single specific entity; various layers of the information channel in the main stems of the channel-collaterals are composed of optimized structure tissues. Hence, the structure of this information channel of channel-collateral system is an overall-optimized, sequential and compatible systemic structure. From this neodoxy, the author brings forward a working principle of channel-collaterals, which is supported theoretically by bio-auxology. The longitudinal distribution of the main stems of meridian-collaterals is considered to result from that in the process of the animal evolution, in the animals moving forward, the microscopic complicated movement of intracorporeal information and energy molecules is related to the forward macroscopic and non-uniform movement of organism in trans-measure. Its impulse and kinetic momentum forms a main vector in the longitudinal direction of the body (the direction of the main stem of channel-collaterals). In order to adapt to and utilize natural regularities, the main stems of the channel-collaterals gradually differentiate and evolve in the living organism, forming a whole system. The "hypothesis of biological origin of channel-collateral system" and "that of information channel of the channel-collaterals in the body" constitute a relatively complete theoretical system framework.

  15. Channel characteristics and coordination in three-echelon dual-channel supply chain

    Science.gov (United States)

    Saha, Subrata

    2016-02-01

    We explore the impact of channel structure on the manufacturer, the distributer, the retailer and the entire supply chain by considering three different channel structures in radiance of with and without coordination. These structures include a traditional retail channel and two manufacturer direct channels with and without consistent pricing. By comparing the performance of the manufacturer, the distributer and the retailer, and the entire supply chain in three different supply chain structures, it is established analytically that, under some conditions, a dual channel can outperform a single retail channel; as a consequence, a coordination mechanism is developed that not only coordinates the dual channel but also outperforms the non-cooperative single retail channel. All the analytical results are further analysed through numerical examples.

  16. Relational databases for rare disease study: application to vascular anomalies.

    Science.gov (United States)

    Perkins, Jonathan A; Coltrera, Marc D

    2008-01-01

    To design a relational database integrating clinical and basic science data needed for multidisciplinary treatment and research in the field of vascular anomalies. Based on data points agreed on by the American Society of Pediatric Otolaryngology (ASPO) Vascular Anomalies Task Force. The database design enables sharing of data subsets in a Health Insurance Portability and Accountability Act (HIPAA)-compliant manner for multisite collaborative trials. Vascular anomalies pose diagnostic and therapeutic challenges. Our understanding of these lesions and treatment improvement is limited by nonstandard terminology, severity assessment, and measures of treatment efficacy. The rarity of these lesions places a premium on coordinated studies among multiple participant sites. The relational database design is conceptually centered on subjects having 1 or more lesions. Each anomaly can be tracked individually along with their treatment outcomes. This design allows for differentiation between treatment responses and untreated lesions' natural course. The relational database design eliminates data entry redundancy and results in extremely flexible search and data export functionality. Vascular anomaly programs in the United States. A relational database correlating clinical findings and photographic, radiologic, histologic, and treatment data for vascular anomalies was created for stand-alone and multiuser networked systems. Proof of concept for independent site data gathering and HIPAA-compliant sharing of data subsets was demonstrated. The collaborative effort by the ASPO Vascular Anomalies Task Force to create the database helped define a common vascular anomaly data set. The resulting relational database software is a powerful tool to further the study of vascular anomalies and the development of evidence-based treatment innovation.

  17. Cell proliferation along vascular islands during microvascular network growth

    Directory of Open Access Journals (Sweden)

    Kelly-Goss Molly R

    2012-06-01

    Full Text Available Abstract Background Observations in our laboratory provide evidence of vascular islands, defined as disconnected endothelial cell segments, in the adult microcirculation. The objective of this study was to determine if vascular islands are involved in angiogenesis during microvascular network growth. Results Mesenteric tissues, which allow visualization of entire microvascular networks at a single cell level, were harvested from unstimulated adult male Wistar rats and Wistar rats 3 and 10 days post angiogenesis stimulation by mast cell degranulation with compound 48/80. Tissues were immunolabeled for PECAM and BRDU. Identification of vessel lumens via injection of FITC-dextran confirmed that endothelial cell segments were disconnected from nearby patent networks. Stimulated networks displayed increases in vascular area, length density, and capillary sprouting. On day 3, the percentage of islands with at least one BRDU-positive cell increased compared to the unstimulated level and was equal to the percentage of capillary sprouts with at least one BRDU-positive cell. At day 10, the number of vascular islands per vascular area dramatically decreased compared to unstimulated and day 3 levels. Conclusions These results show that vascular islands have the ability to proliferate and suggest that they are able to incorporate into the microcirculation during the initial stages of microvascular network growth.

  18. Functional Importance of L- and P/Q-Type Voltage-Gated Calcium Channels in Human Renal Vasculature

    DEFF Research Database (Denmark)

    Hansen, Pernille B; Poulsen, Christian B; Walter, Steen

    2011-01-01

    Calcium channel blockers are widely used for treatment of hypertension, because they decrease peripheral vascular resistance through inhibition of voltage-gated calcium channels. Animal studies of renal vasculature have shown expression of several types of calcium channels that are involved......-type subtype (Ca(v) 3.1 and Ca(v) 3.2) voltage-gated calcium channels (Ca(v)s), and quantitative PCR showed highest expression of L-type channels in renal arteries and variable expression between patients of subtypes of calcium channels in intrarenal vessels. Immunohistochemical labeling of kidney sections...

  19. A Perspective on the MIMO Wiretap Channel

    KAUST Repository

    Oggier, Frederique; Hassibi, Babak

    2015-01-01

    A wiretap channel is a communication channel between a transmitter Alice and a legitimate receiver Bob, in the presence of an eavesdropper Eve. The goal of communication is to achieve reliability between Alice and Bob, but also confidentiality despite Eve’s presence. Wiretap channels are declined in all kinds of flavors, depending on the underlying channels used by the three players: discrete memoryless channels, additive Gaussian noise channels, or fading channels, to name a few. In this survey, we focus on the case where the three players use multiple-antenna channels with Gaussian noise to communicate. After summarizing known results for multiple-input–multiple-output (MIMO) channels, both in terms of achievable reliable data rate (capacity) and code design, we introduce the MIMO wiretap channel. We then state the MIMO wiretap capacity, summarize the idea of the proof(s) behind this result, and comment on the insights given by the proofs on the physical meaning of the secrecy capacity. We finally discuss design criteria for MIMO wiretap codes.

  20. A Perspective on the MIMO Wiretap Channel

    KAUST Repository

    Oggier, Frederique

    2015-10-01

    A wiretap channel is a communication channel between a transmitter Alice and a legitimate receiver Bob, in the presence of an eavesdropper Eve. The goal of communication is to achieve reliability between Alice and Bob, but also confidentiality despite Eve’s presence. Wiretap channels are declined in all kinds of flavors, depending on the underlying channels used by the three players: discrete memoryless channels, additive Gaussian noise channels, or fading channels, to name a few. In this survey, we focus on the case where the three players use multiple-antenna channels with Gaussian noise to communicate. After summarizing known results for multiple-input–multiple-output (MIMO) channels, both in terms of achievable reliable data rate (capacity) and code design, we introduce the MIMO wiretap channel. We then state the MIMO wiretap capacity, summarize the idea of the proof(s) behind this result, and comment on the insights given by the proofs on the physical meaning of the secrecy capacity. We finally discuss design criteria for MIMO wiretap codes.

  1. Uncertainty analysis for hot channel

    International Nuclear Information System (INIS)

    Panka, I.; Kereszturi, A.

    2006-01-01

    The fulfillment of the safety analysis acceptance criteria is usually evaluated by separate hot channel calculations using the results of neutronic or/and thermo hydraulic system calculations. In case of an ATWS event (inadvertent withdrawal of control assembly), according to the analysis, a number of fuel rods are experiencing DNB for a longer time and must be regarded as failed. Their number must be determined for a further evaluation of the radiological consequences. In the deterministic approach, the global power history must be multiplied by different hot channel factors (kx) taking into account the radial power peaking factors for each fuel pin. If DNB occurs it is necessary to perform a few number of hot channel calculations to determine the limiting kx leading just to DNB and fuel failure (the conservative DNBR limit is 1.33). Knowing the pin power distribution from the core design calculation, the number of failed fuel pins can be calculated. The above procedure can be performed by conservative assumptions (e.g. conservative input parameters in the hot channel calculations), as well. In case of hot channel uncertainty analysis, the relevant input parameters (k x, mass flow, inlet temperature of the coolant, pin average burnup, initial gap size, selection of power history influencing the gap conductance value) of hot channel calculations and the DNBR limit are varied considering the respective uncertainties. An uncertainty analysis methodology was elaborated combining the response surface method with the one sided tolerance limit method of Wilks. The results of deterministic and uncertainty hot channel calculations are compared regarding to the number of failed fuel rods, max. temperature of the clad surface and max. temperature of the fuel (Authors)

  2. Laser-assisted vascular anastomosis

    Science.gov (United States)

    Kao, Race L.; Tsao-Wu, George; Magovern, George J.

    1990-06-01

    The milliwatt CO2 laser and a thermal activated binding compound (20% serum albumin) were used for microvascular anastomoses. Under general anesthesia, the femoral arteries (0.7 to 1.0 mm diameter) of 6 rats were isolated. After the left femoral artery in each rat was clamped and transected, the vessel was held together with 3 equidistant 10-0 Xomed sutures. The cut edges were coated 3 to 4 times with the albumin solution and sealed with the CO2 laser (power density = 120 W/cm2). The binding compound solidified to a translucent tensile substance which supported the anastomosis until self healing and repair were achieved. The right femoral artery was used as sham operated control. Complete hemostasis and patency were observed in every case immediately and at 1, 3, and 6 months following surgery. The binding compound absorbed most of the laser energy thus minimizing thermal injury to the underlying tissue. Mongrel dogs weighing 28 to 33 kg were anesthetized and prepared for sterile surgical procedures. In 5 dogs, the femoral and jugular veins were exposed, transected, and anastomosed using a CO2 laser (Sharplan 1040) with the binding compound. In another 12 dogs, cephalic veins were isolated and used for aortocoronary artery bypass procedures. The Sharplan 1040 CO2 laser and 20% albumin solution were utilized to complete the coronary anastomoses in 6 dogs, and 6 dogs were used as controls by suturing the vessels. Again, hemostasis, patency, and minimal tissue damage were observed immediately and 6 weeks after the procedures. Improved surgical results, reduced operating time, minimized tissue damage, and enhanced anastomotic integrity are the advantages of laser assisted vascular anastomosis with a thermal activated binding compound.

  3. [Vascular access guidelines for hemodialysis].

    Science.gov (United States)

    Rodríguez Hernández, J A; González Parra, E; Julián Gutiérrez, J M; Segarra Medrano, A; Almirante, B; Martínez, M T; Arrieta, J; Fernández Rivera, C; Galera, A; Gallego Beuter, J; Górriz, J L; Herrero, J A; López Menchero, R; Ochando, A; Pérez Bañasco, V; Polo, J R; Pueyo, J; Ruiz, Camps I; Segura Iglesias, R

    2005-01-01

    Quality of vascular access (VA) has a remarkable influence in hemodialysis patients outcomes. Dysfunction of VA represents a capital cause of morbi-mortality of these patients as well an increase in economical. Spanish Society of Neprhology, aware of the problem, has decided to carry out a revision of the issue with the aim of providing help in comprehensión and treatment related with VA problems, and achieving an homogenization of practices in three mayor aspects: to increase arteriovenous fistula utilization as first vascular access, to increment vascular access monitoring practice and rationalise central catheters use. We present a consensus document elaborated by a multidisciplinar group composed by nephrologists, vascular surgeons, interventional radiologysts, infectious diseases specialists and nephrological nurses. Along six chapters that cover patient education, creation of VA, care, monitoring, complications and central catheters, we present the state of the art and propose guidelines for the best practice, according different evidence based degrees, with the intention to provide help at the professionals in order to make aproppiate decissions. Several quality standars are also included.

  4. Vascular aspects of multiple sclerosis

    NARCIS (Netherlands)

    D'haeseleer, Miguel; Cambron, Melissa; Vanopdenbosch, Ludo; De Keyser, Jacques

    Three types of vascular dysfunction have been described in multiple sclerosis (MS). First, findings from epidemiological studies suggest that patients with MS have a higher risk for ischaemic stroke than people who do not have MS. The underlying mechanism is unknown, but might involve endothelial

  5. Inactivation of Mechanically Activated Piezo1 Ion Channels Is Determined by the C-Terminal Extracellular Domain and the Inner Pore Helix

    Directory of Open Access Journals (Sweden)

    Jason Wu

    2017-11-01

    Full Text Available Piezo proteins form mechanically activated ion channels that are responsible for our sense of light touch, proprioception, and vascular blood flow. Upon activation by mechanical stimuli, Piezo channels rapidly inactivate in a voltage-dependent manner through an unknown mechanism. Inactivation of Piezo channels is physiologically important, as it modulates overall mechanical sensitivity, gives rise to frequency filtering of repetitive mechanical stimuli, and is itself the target of numerous human disease-related channelopathies that are not well understood mechanistically. Here, we identify the globular C-terminal extracellular domain as a structure that is sufficient to confer the time course of inactivation and a single positively charged lysine residue at the adjacent inner pore helix as being required for its voltage dependence. Our results are consistent with a mechanism for inactivation that is mediated through voltage-dependent conformations of the inner pore helix and allosteric coupling with the C-terminal extracellular domain.

  6. The KATP channel in migraine pathophysiology: a novel therapeutic target for migraine.

    Science.gov (United States)

    Al-Karagholi, Mohammad Al-Mahdi; Hansen, Jakob Møller; Severinsen, Johanne; Jansen-Olesen, Inger; Ashina, Messoud

    2017-08-23

    To review the distribution and function of K ATP channels, describe the use of K ATP channels openers in clinical trials and make the case that these channels may play a role in headache and migraine. K ATP channels are widely present in the trigeminovascular system and play an important role in the regulation of tone in cerebral and meningeal arteries. Clinical trials using synthetic K ATP channel openers report headache as a prevalent-side effect in non-migraine sufferers, indicating that K ATP channel opening may cause headache, possibly due to vascular mechanisms. Whether K ATP channel openers can provoke migraine in migraine sufferers is not known. We suggest that K ATP channels may play an important role in migraine pathogenesis and could be a potential novel therapeutic anti-migraine target.

  7. Sales promotions and channel coordination

    NARCIS (Netherlands)

    B. Wierenga (Berend); H. Soethoudt (Han)

    2009-01-01

    textabstractConsumer sales promotions are usually the result of the decisions of two marketing channel parties, the manufacturer and the retailer. In making these decisions, each party normally follows its own interest: i.e. maximizes its own profit. Unfortunately, this results in a suboptimal

  8. Sales promotion and channel coordination

    NARCIS (Netherlands)

    Wierenga, B.; Soethoudt, J.M.

    2010-01-01

    Consumer sales promotions are usually the result of the decisions of two marketing channel parties, the manufacturer and the retailer. In making these decisions, each party normally follows its own interest: i.e. maximizes its own profit. Unfortunately, this results in a suboptimal outcome for the

  9. Lifestyle and metabolic approaches to maximizing erectile and vascular health.

    Science.gov (United States)

    Meldrum, D R; Gambone, J C; Morris, M A; Esposito, K; Giugliano, D; Ignarro, L J

    2012-01-01

    Oxidative stress and inflammation, which disrupt nitric oxide (NO) production directly or by causing resistance to insulin, are central determinants of vascular diseases including ED. Decreased vascular NO has been linked to abdominal obesity, smoking and high intakes of fat and sugar, which all cause oxidative stress. Men with ED have decreased vascular NO and circulating and cellular antioxidants. Oxidative stress and inflammatory markers are increased in men with ED, and all increase with age. Exercise increases vascular NO, and more frequent erections are correlated with decreased ED, both in part due to stimulation of endothelial NO production by shear stress. Exercise and weight loss increase insulin sensitivity and endothelial NO production. Potent antioxidants or high doses of weaker antioxidants increase vascular NO and improve vascular and erectile function. Antioxidants may be particularly important in men with ED who smoke, are obese or have diabetes. Omega-3 fatty acids reduce inflammatory markers, decrease cardiac death and increase endothelial NO production, and are therefore critical for men with ED who are under age 60 years, and/or have diabetes, hypertension or coronary artery disease, who are at increased risk of serious or even fatal cardiac events. Phosphodiesterase inhibitors have recently been shown to improve antioxidant status and NO production and allow more frequent and sustained penile exercise. Some angiotensin II receptor blockers decrease oxidative stress and improve vascular and erectile function and are therefore preferred choices for lowering blood pressure in men with ED. Lifestyle modifications, including physical and penile-specific exercise, weight loss, omega-3 and folic acid supplements, reduced intakes of fat and sugar, and improved antioxidant status through diet and/or supplements should be integrated into any comprehensive approach to maximizing erectile function, resulting in greater overall success and patient

  10. Vascular Trauma Operative Experience is Inadequate in General Surgery Programs.

    Science.gov (United States)

    Yan, Huan; Maximus, Steven; Koopmann, Matthew; Keeley, Jessica; Smith, Brian; Virgilio, Christian de; Kim, Dennis Y

    2016-05-01

    Vascular injuries may be challenging, particularly for surgeons who have not received formal vascular surgery fellowship training. Lack of experience and improper technique can result in significant complications. The objective of this study was to examine changes in resident experience with operative vascular trauma over time. A retrospective review was performed using Accreditation Council for Graduate Medical Education (ACGME) case logs of general surgery residents graduating between 2004 and 2014 at 2 academic, university-affiliated institutions associated with level 1 trauma centers. The primary outcome was number of reported vascular trauma operations, stratified by year of graduation and institution. A total of 112 residents graduated in the study period with a median 7 (interquartile range 4.5-13.5) vascular trauma cases per resident. Fasciotomy and exposure and/or repair of peripheral vessels constituted the bulk of the operative volume. Linear regression showed no significant trend in cases with respect to year of graduation (P = 0.266). Residents from program A (n = 53) reported a significantly higher number of vascular trauma cases when compared with program B (n = 59): 12.0 vs. 5.0 cases, respectively (P < 0.001). Level 1 trauma center verification does not guarantee sufficient exposure to vascular trauma. The operative exposure in program B is reflective of the national average of 4.0 cases per resident as reported by the ACGME, and this trend is unlikely to change in the near future. Fellowship training may be critical for surgeons who plan to work in a trauma setting, particularly in areas lacking vascular surgeons. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. TRPV6 channels.

    Science.gov (United States)

    Fecher-Trost, Claudia; Weissgerber, Petra; Wissenbach, Ulrich

    2014-01-01

    TRPV6 (former synonyms ECAC2, CaT1, CaT-like) displays several specific features which makes it unique among the members of the mammalian Trp gene family (1) TRPV6 (and its closest relative, TRPV5) are the only highly Ca(2+)-selective channels of the entire TRP superfamily (Peng et al. 1999; Wissenbach et al. 2001; Voets et al. 2004). (2) Translation of Trpv6 initiates at a non-AUG codon, at ACG, located upstream of the annotated AUG, which is not used for initiation (Fecher-Trost et al. 2013). The ACG codon is nevertheless decoded by methionine. Not only a very rare event in eukaryotic biology, the full-length TRPV6 protein existing in vivo comprises an amino terminus extended by 40 amino acid residues compared to the annotated truncated TRPV6 protein which has been used in most studies on TRPV6 channel activity so far. (In the following numbering occurs according to this full-length protein, with the numbers of the so far annotated truncated protein in brackets). (3) Only in humans a coupled polymorphism of Trpv6 exists causing three amino acid exchanges and resulting in an ancestral Trpv6 haplotype and a so-called derived Trpv6 haplotype (Wissenbach et al. 2001). The ancestral allele encodes the amino acid residues C197(157), M418(378) and M721(681) and the derived alleles R197(157), V418(378) and T721(681). The ancestral haplotype is found in all species, the derived Trpv6 haplotype has only been identified in humans, and its frequency increases with the distance to the African continent. Apparently the Trpv6 gene has been a strong target for selection in humans, and its derived variant is one of the few examples showing consistently differences to the orthologues genes of other primates (Akey et al. 2004, 2006; Stajich and Hahn 2005; Hughes et al. 2008). (4) The Trpv6 gene expression is significantly upregulated in several human malignancies including the most common cancers, prostate and breast cancer (Wissenbach et al. 2001; Zhuang et al. 2002; Fixemer et al

  12. Ion channels in plants.

    Science.gov (United States)

    Hedrich, Rainer

    2012-10-01

    Since the first recordings of single potassium channel activities in the plasma membrane of guard cells more than 25 years ago, patch-clamp studies discovered a variety of ion channels in all cell types and plant species under inspection. Their properties differed in a cell type- and cell membrane-dependent manner. Guard cells, for which the existence of plant potassium channels was initially documented, advanced to a versatile model system for studying plant ion channel structure, function, and physiology. Interestingly, one of the first identified potassium-channel genes encoding the Shaker-type channel KAT1 was shown to be highly expressed in guard cells. KAT1-type channels from Arabidopsis thaliana and its homologs from other species were found to encode the K(+)-selective inward rectifiers that had already been recorded in early patch-clamp studies with guard cells. Within the genome era, additional Arabidopsis Shaker-type channels appeared. All nine members of the Arabidopsis Shaker family are localized at the plasma membrane, where they either operate as inward rectifiers, outward rectifiers, weak voltage-dependent channels, or electrically silent, but modulatory subunits. The vacuole membrane, in contrast, harbors a set of two-pore K(+) channels. Just very recently, two plant anion channel families of the SLAC/SLAH and ALMT/QUAC type were identified. SLAC1/SLAH3 and QUAC1 are expressed in guard cells and mediate Slow- and Rapid-type anion currents, respectively, that are involved in volume and turgor regulation. Anion channels in guard cells and other plant cells are key targets within often complex signaling networks. Here, the present knowledge is reviewed for the plant ion channel biology. Special emphasis is drawn to the molecular mechanisms of channel regulation, in the context of model systems and in the light of evolution.

  13. The impact of various scaffold components on vascularized bone constructs.

    Science.gov (United States)

    Eweida, Ahmad; Schulte, Matthias; Frisch, Oliver; Kneser, Ulrich; Harhaus, Leila

    2017-06-01

    . Collagen matrix and a smaller particle size provided more favorable results in terms of vascularization and tissue formation than diluted fibrin and larger Nanobone particles. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  14. A multifaceted approach to maximize erectile function and vascular health.

    Science.gov (United States)

    Meldrum, David R; Gambone, Joseph C; Morris, Marge A; Ignarro, Louis J

    2010-12-01

    To review the role of various factors influencing vascular nitric oxide (NO) and cyclic GMP, and consequently, erectile function and vascular health. Pertinent publications are reviewed. Daily moderate exercise stimulates vascular NO production. Maintenance of normal body weight and waist/hip ratio allows NO stimulation by insulin. Decreased intake of fat, sugar, and simple carbohydrates rapidly converted to sugar reduces the adverse effects of fatty acids and sugar on endothelial NO production. Omega-3 fatty acids stimulate endothelial NO release. Antioxidants boost NO production and prevent NO breakdown. Folic acid, calcium, vitamin C, and vitamin E support the biochemical pathways leading to NO release. Cessation of smoking and avoidance of excessive alcohol preserve normal endothelial function. Moderate use of alcohol and certain proprietary supplements may favorably influence erectile and vascular function. Treatment of any remaining testosterone deficit will both increase erectile function and reduce any associated metabolic syndrome. After production of NO and cyclic GMP are improved, use of phosphodiesterase-5 inhibitors should result in greater success in treating remaining erectile dysfunction. Recent studies have also suggested positive effects of phosphodiesterase-5 inhibitors on vascular function. A multifaceted approach will maximize both erectile function and vascular health. Copyright © 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Vascular and valvular calcifications in chronic hemodialysis patients

    Directory of Open Access Journals (Sweden)

    María Elena Bruzzone

    2014-12-01

    Full Text Available Introduction: Vascular and valvular calcifications are a frequent complication in dialyzed patients and are connected to an increased morbi-mortality. Many radiological methods (TAC multiple slices and with electrons emission have been used to investigate the presence of vascular calcifications in this population, but only few works have been focused on simple radiology. Objectives: The objectives of this work are to evaluate vascular calcifications by means of Kauppila index in hemodialysis prevalent patients, identify linked risk factors and determine their association with heart valves calcification. Methods: 95 stable patients under hemodialysis were surveyed during a period of 6 months longer. Abdominal Rx simple profile were performed on all patients to evaluate calcification of abdominal aorta by Kauppila index and twodimensional echocardiogram to detect valvular calcifications. Data were collected about sex, age, diabetes, Hypertension, tabaquism, dislipemia and bone-mineral metabolism. Results: 64.5% of the patients showed vascular calcifications. Average Kauppila index was 6.25. Age and time on dialysis correlated with vascular calcifications. In 31.6 % of individuals valvular calcifications were found, which presented significant association with diabetes and Kauppila Index. Conclusions: Vascular and valvular calcifications were frequent in the surveyed population. Kauppila index correlated with age, time on dialysis and valvular calcifications. Heart valves calcification was associated with diabetes.

  16. Arterial complications of vascular Ehlers-Danlos syndrome.

    Science.gov (United States)

    Eagleton, Matthew J

    2016-12-01

    Vascular Ehlers-Danlos syndrome (EDS) is a relatively rare genetic syndrome that occurs owing to disorders in the metabolism of fibrillary collagen. These defects affect the soft connective tissues resulting in abnormalities in the skin, joints, hollow organs, and blood vessels. Patients with these defects frequently present at a young age with spontaneous arterial complications involving the medium-sized arteries. Complications involving the hollow organs, such as spontaneous colonic perforation, are observed as well. Given the fragility of the soft tissue, open and endovascular intervention on patients with vascular EDS is fraught with high complication rates. A PubMed search was performed to identify manuscripts published related to vascular EDS. This search included more than 747 articles. These findings were cross-referenced using key terms, including endovascular, embolization, surgery, genetics, pathophysiology, connective tissue disorders, vascular complications, systematic review, type III collagen, and COL3A1. The references in key articles and review articles were evaluated for additional resources not identified in the PubMed search. Care must be taken to balance the risk of intervention vs the risk of continued observation. Life-threatening hemorrhage, however, mandates intervention. With careful, altered approaches to tissue handling, endovascular approaches may provide a safer option for managing the arterial complications observed in patients with vascular EDS. Additional hope may also be found in the use of pharmacologic agents that reduce the incidence and severity of the arterial complications. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  17. Vascular Risk Factors and Clinical Progression in Spinocerebellar Ataxias

    Directory of Open Access Journals (Sweden)

    Raymond Y. Lo

    2015-02-01

    Full Text Available Background: The contributions of vascular risk factors to spinocerebellar ataxia (SCA are not known.Methods: We studied 319 participants with SCA 1, 2, 3, and 6 and repeatedly measured clinical severity using the Scale for Assessment and Rating of Ataxia (SARA for 2 years. Vascular risk factors were summarized by CHA2DS2-VASc scores as the vascular risk factor index. We employed regression models to study the effects of vascular risk factors on ataxia onset and progression after adjusting for age, sex, and pathological CAG repeats. Our secondary analyses took hyperlipidemia into account.Results: Nearly 60% of SCA participants were at low vascular risks with CHA2DS2-VASc = 0, and 31% scored 2 or greater. Higher CHA2DS2-VASc scores were not associated with either earlier onset or faster progression of ataxia. These findings were not altered after accounting for hyperlipidemia. Discussion: Vascular risks are not common in SCAs and are not associated with earlier onset or faster ataxia progression.

  18. FGF-dependent metabolic control of vascular development

    Science.gov (United States)

    Yu, Pengchun; Alves, Tiago C.; Fang, Jennifer S.; Xie, Yi; Zhu, Jie; Chen, Zehua; De Smet, Frederik; Zhang, Jiasheng; Jin, Suk-Won; Sun, Lele; Sun, Hongye; Kibbey, Richard G.; Hirschi, Karen K.; Hay, Nissim; Carmeliet, Peter; Chittenden, Thomas W.; Eichmann, Anne; Potente, Michael; Simons, Michael

    2017-01-01

    Blood and lymphatic vasculatures are intimately involved in tissue oxygenation and fluid homeostasis maintenance. Assembly of these vascular networks involves sprouting, migration and proliferation of endothelial cells. Recent studies have suggested that changes in cellular metabolism are of importance to these processes1. While much is known about vascular endothelial growth factor (VEGF)-dependent regulation of vascular development and metabolism2,3, little is understood about the role of fibroblast growth factors (FGFs) in this context4. Here we identify FGF receptor (FGFR) signaling as a critical regulator of vascular development. This is achieved by FGF-dependent control of c-MYC (MYC) expression that, in turn, regulates expression of the glycolytic enzyme hexokinase 2 (HK2). A decrease in HK2 levels in the absence of FGF signaling inputs results in decreased glycolysis leading to impaired endothelial cell proliferation and migration. Pan-endothelial- and lymphatic-specific Hk2 knockouts phenocopy blood and/or lymphatic vascular defects seen in Fgfr1/r3 double mutant mice while HK2 overexpression partially rescues the defects caused by suppression of FGF signaling. Thus, FGF-dependent regulation of endothelial glycolysis is a pivotal process in developmental and adult vascular growth and development. PMID:28467822

  19. The minimum yield in channeling

    International Nuclear Information System (INIS)

    Uguzzoni, A.; Gaertner, K.; Lulli, G.; Andersen, J.U.

    2000-01-01

    A first estimate of the minimum yield was obtained from Lindhard's theory, with the assumption of a statistical equilibrium in the transverse phase-space of channeled particles guided by a continuum axial potential. However, computer simulations have shown that this estimate should be corrected by a fairly large factor, C (approximately equal to 2.5), called the Barrett factor. We have shown earlier that the concept of a statistical equilibrium can be applied to understand this result, with the introduction of a constraint in phase-space due to planar channeling of axially channeled particles. Here we present an extended test of these ideas on the basis of computer simulation of the trajectories of 2 MeV α particles in Si. In particular, the gradual trend towards a full statistical equilibrium is studied. We also discuss the introduction of this modification of standard channeling theory into descriptions of the multiple scattering of channeled particles (dechanneling) by a master equation and show that the calculated minimum yields are in very good agreement with the results of a full computer simulation

  20. Subclinical hypothyroidism after vascular complicated pregnancy

    NARCIS (Netherlands)

    Zanden, M. van der; Hop-de Groot, R.J.; Sweep, F.C.; Ross, H.A.; Heijer, M. den; Spaanderman, M.E.A.

    2013-01-01

    OBJECTIVE: Women with a history of vascular complicated pregnancy are at risk for developing remote cardiovascular disease. It is associated with underlying cardiovascular risk factors both jeopardizing trophoblast and vascular function. Subclinical hypothyroidism may relate to both conditions.

  1. Pediatric central nervous system vascular malformations

    International Nuclear Information System (INIS)

    Burch, Ezra A.; Orbach, Darren B.

    2015-01-01

    Pediatric central nervous system (CNS) vascular anomalies include lesions found only in the pediatric population and also the full gamut of vascular lesions found in adults. Pediatric-specific lesions discussed here include infantile hemangioma, vein of Galen malformation and dural sinus malformation. Some CNS vascular lesions that occur in adults, such as arteriovenous malformation, have somewhat distinct manifestations in children, and those are also discussed. Additionally, children with CNS vascular malformations often have associated broader vascular conditions, e.g., PHACES (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac anomalies, eye anomalies and sternal anomalies), hereditary hemorrhagic telangiectasia, and capillary malformation-arteriovenous malformation syndrome (related to the RASA1 mutation). The treatment of pediatric CNS vascular malformations has greatly benefited from advances in endovascular therapy, including technical advances in adult interventional neuroradiology. Dramatic advances in therapy are expected to stem from increased understanding of the genetics and vascular biology that underlie pediatric CNS vascular malformations. (orig.)

  2. Pediatric central nervous system vascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Burch, Ezra A. [Brigham and Women' s Hospital, Department of Radiology, Boston, MA (United States); Orbach, Darren B. [Boston Children' s Hospital, Neurointerventional Radiology, Boston, MA (United States)

    2015-09-15

    Pediatric central nervous system (CNS) vascular anomalies include lesions found only in the pediatric population and also the full gamut of vascular lesions found in adults. Pediatric-specific lesions discussed here include infantile hemangioma, vein of Galen malformation and dural sinus malformation. Some CNS vascular lesions that occur in adults, such as arteriovenous malformation, have somewhat distinct manifestations in children, and those are also discussed. Additionally, children with CNS vascular malformations often have associated broader vascular conditions, e.g., PHACES (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac anomalies, eye anomalies and sternal anomalies), hereditary hemorrhagic telangiectasia, and capillary malformation-arteriovenous malformation syndrome (related to the RASA1 mutation). The treatment of pediatric CNS vascular malformations has greatly benefited from advances in endovascular therapy, including technical advances in adult interventional neuroradiology. Dramatic advances in therapy are expected to stem from increased understanding of the genetics and vascular biology that underlie pediatric CNS vascular malformations. (orig.)

  3. ESRD QIP - Vascular Access - Payment Year 2018

    Data.gov (United States)

    U.S. Department of Health & Human Services — This dataset includes facility details, performance rates, vascular access topic measure score, and the state and national average measure scores for the vascular...

  4. Functional and pharmacological consequences of the distribution of voltage-gated calcium channels in the renal blood vessels.

    Science.gov (United States)

    Hansen, P B L

    2013-04-01

    Calcium channel blockers are widely used to treat hypertension because they inhibit voltage-gated calcium channels that mediate transmembrane calcium influx in, for example, vascular smooth muscle and cardiomyocytes. The calcium channel family consists of several subfamilies, of which the L-type is usually associated with vascular contractility. However, the L-, T- and P-/Q-types of calcium channels are present in the renal vasculature and are differentially involved in controlling vascular contractility, thereby contributing to regulation of kidney function and blood pressure. In the preglomerular vascular bed, all the three channel families are present. However, the T-type channel is the only channel in cortical efferent arterioles which is in contrast to the juxtamedullary efferent arteriole, and that leads to diverse functional effects of L- and T-type channel inhibition. Furthermore, by different mechanisms, T-type channels may contribute to both constriction and dilation of the arterioles. Finally, P-/Q-type channels are involved in the regulation of human intrarenal arterial contractility. The calcium blockers used in the clinic affect not only L-type but also P-/Q- and T-type channels. Therefore, the distinct effect obtained by inhibiting a given subtype or set of channels under experimental settings should be considered when choosing a calcium blocker for treatment. T-type channels seem to be crucial for regulating the GFR and the filtration fraction. Use of blockers is expected to lead to preferential efferent vasodilation, reduction of glomerular pressure and proteinuria. Therefore, renovascular T-type channels might provide novel therapeutic targets, and may have superior renoprotective effects compared to conventional calcium blockers. Acta Physiologica © 2013 Scandinavian Physiological Society.

  5. Protein kinase A and C regulate leak potassium currents in freshly isolated vascular myocytes from the aorta.

    Directory of Open Access Journals (Sweden)

    Sébastien Hayoz

    Full Text Available We tested the hypothesis that protein kinase A (PKA inhibits K2P currents activated by protein kinase C (PKC in freshly isolated aortic myocytes. PDBu, the PKC agonist, applied extracellularly, increased the amplitude of the K2P currents in the presence of the "cocktail" of K(+ channel blockers. Gö 6976 significantly reduced the increase of the K2P currents by PDBu suggesting the involvement of either α or β isoenzymes of PKC. We found that forskolin, or membrane permeable cAMP, did not inhibit K2P currents activated by the PKC. However, when PKA agonists were added prior to PDBu, they produced a strong decrease in the K2P current amplitudes activated by PKC. Inhibition of PDBu-elicited K2P currents by cAMP agonists was not prevented by the treatment of vascular smooth muscle cells with PKA antagonists (H-89 and Rp-cAMPs. Zn(2+ and Hg(2+ inhibited K2P currents in one population of cells, produced biphasic responses in another population, and increased the amplitude of the PDBu-elicited K(+ currents in a third population of myocytes, suggesting expression of several K2P channel types. We found that cAMP agonists inhibited biphasic responses and increase of amplitude of the PDBu-elicited K2P currents produced by Zn(2+ and Hg(2. 6-Bnz-cAMp produced a significantly altered pH sensitivity of PDBu-elicited K2P-currents, suggesting the inhibition of alkaline-activated K2P-currents. These results indicate that 6-Bnz-cAMP and other cAMP analogs may inhibit K2P currents through a PKA-independent mechanism. cAMP analogs may interact with unidentified proteins involved in K2P channel regulation. This novel cellular mechanism could provide insights into the interplay between PKC and PKA pathways that regulate vascular tone.

  6. Export channel pricing management for integrated solutions

    OpenAIRE

    Roine, Henna; Sainio, Liisa-Maija; Saarenketo, Sami

    2012-01-01

    This article studies systems integrators' export channel pricing management for integrated solutions. We find support from our empirical case study for the notion that a systems integrator's export channel pricing strategy is multidimensional and dependent on international pricing environment and partner characteristics and that export partnerships have unique implications on a systems integrator's pricing process. The results show that giving up pricing control in export channel context may ...

  7. Quantum privacy and Schur product channels

    Science.gov (United States)

    Levick, Jeremy; Kribs, David W.; Pereira, Rajesh

    2017-12-01

    We investigate the quantum privacy properties of an important class of quantum channels, by making use of a connection with Schur product matrix operations and associated correlation matrix structures. For channels implemented by mutually commuting unitaries, which cannot privatise qubits encoded directly into subspaces, we nevertheless identify private algebras and subsystems that can be privatised by the channels. We also obtain further results by combining our analysis with tools from the theory of quasi-orthogonal operator algebras and graph theory.

  8. Planar channeling in superlattices: Theory

    International Nuclear Information System (INIS)

    Ellison, J.A.; Picraux, S.T.; Allen, W.R.; Chu, W.K.

    1988-01-01

    The well-known continuum model theory for planar channeled energetic particles in perfect crystals is extended to layered crystalline structures and applied to superlattices. In a strained-layer structure, the planar channels with normals which are not perpendicular to the growth direction change their direction at each interface, and this dramatically influences the channeling behavior. The governing equation of motion for a planar channeled ion in a strained-layer superlattice with equal layer thicknesses is a one degree of freedom nonlinear oscillator which is periodically forced with a sequence of δ functions. These δ functions, which are of equal spacing and amplitude with alternating sign, represent the tilts at each of the interfaces. Thus upon matching an effective channeled particle wavelength, corresponding to a natural period of the nonlinear oscillator, to the period of the strained-layer superlattice, corresponding to the periodic forcing, strong resonance effects are expected. The condition of one effective wavelength per period corresponds to a rapid dechanneling at a well-defined depth (catastrophic dechanneling), whereas two wavelengths per period corresponds to no enhanced dechanneling after the first one or two layers (resonance channeling). A phase plane analysis is used to characterize the channeled particle motion. Detailed calculations using the Moliere continuum potential are compared with our previously described modified harmonic model, and new results are presented for the phase plane evolution, as well as the dechanneling as a function of depth, incident angle, energy, and layer thickness. General scaling laws are developed and nearly universal curves are obtained for the dechanneling versus depth under catastrophic dechanneling

  9. Peripheral Vascular Disease

    Science.gov (United States)

    ... smokers aged 20 to 40. Smoking causes the blood vessels to tighten in everyone who smokes. But in people with Buerger’s disease, there is so much tightening in the vessels that a lack of oxygen to the cells (ischemia) or tissue death (necrosis) may result. The symptoms may be different for ...

  10. A Micromechanical RF Channelizer

    Science.gov (United States)

    Akgul, Mehmet

    applications that must be stable against environmental perturbations, such as acceleration or power supply variations. Measurements on fabricated devices in fact confirm predictions by the new model of up to 4x improvement in frequency stability against DC-bias voltage variations for contour-mode disk resonators as the resistance loading their ports increases. By enhancing circuit visualization, this circuit model makes more obvious the circuit design procedures and topologies most beneficial for certain mechanical circuits, e.g., filters and oscillators. The second method enables simultaneous low motional resistance ( Rx 70,000) at 61 MHz using an improved ALD-partial electrode-to-resonator gap filling technique that reduces the Q-limiting surface losses of previous renditions by adding an alumina pre-coating before ALD of the gap-filling high-k dielectric. This effort increases the Q over the ˜10,000 of previous renditions by more than 6x towards demonstration of the first VHF micromechanical resonators in any material, piezoelectric or not, to meet the simultaneous high Q (>50,000) and low motional resistance Rx (gap spacing. Finally, the experimental results introduce a 39nm-gap capacitive transducer, voltage-controlled frequency tuning, and a stress relieving coupled array design that enable a 0.09% bandwidth 223.4 MHz channel-select filter with only 2.7dB of in-band insertion loss and 50dB rejection of out-of-band interferers. This amount of rejection is more than 23dB better than previous capacitive-gap transduced filter designs that did not benefit from sub-50nm gaps. It also comes in tandem with a 20dB shape factor of 2.7 realized by a hierarchical mechanical circuit design utilizing 206 micromechanical circuit elements, all contained in an area footprint of only 600mumx420mum. The key to such low insertion loss for this tiny percent bandwidth is Q's>8,800 supplied by polysilicon disk resonators employing for the first time capacitive transducer gaps small enough to

  11. Laser therapy and sclerotherapy in the treatment of oral and maxillofacial hemangioma and vascular malformations

    Science.gov (United States)

    Crişan, Bogdan; BǎciuÅ£, Mihaela; BǎciuÅ£, Grigore; Crişan, Liana; Bran, Simion; Rotar, Horatiu; Moldovan, Iuliu; Vǎcǎraş, Sergiu; Mitre, Ileana; Barbur, Ioan; Magdaş, Andreea; Dinu, Cristian

    2016-03-01

    Hemangioma and vascular malformations in the field of oral and maxillofacial surgery is a pathology more often found in recent years in patients. The aim of this study was to evaluate the efficacy of the laser photocoagulation performed with a diode laser (Ga-Al-As) 980 nm wavelength in the treatment of vascular lesions which are located on the oral and maxillofacial areas, using color Doppler ultrasonography for evaluation of the results. We also made a comparison between laser therapy and sclerotherapy in order to establish treatment protocols and recommendations associated with this pathology. We conducted a controlled study on a group of 92 patients (38 male and 54 female patients, with an average age of 36 years) having low flow hemangioma and vascular malformations. Patients in this trial received one of the methods of treatment for vascular lesions such as hemangioma and vascular malformations: laser therapy or sclerotherapy. After laser therapy we have achieved a reduction in size of hemangioma and vascular malformations treated with such a procedure, and the aesthetic results were favorable. No reperfusion or recanalization of laser treated vascular lesions was observed after an average follow-up of 6 to 12 months. In case of sclerotherapy a reduction in the size of vascular lesions was also obtained. The 980 nm diode laser has been proved to be an effective tool in the treatment of hemangioma and vascular malformations in oral and maxillofacial area. Laser therapy in the treatment of vascular lesions was more effective than the sclerotherapy procedure.

  12. Intramuscular vascular malformations of an extremity: findings on MR imaging and pathologic correlation

    International Nuclear Information System (INIS)

    Kim, E.Y.; Ahn, J.M.; Yoon, H.K.; Do, Y.S.; Kim, S.H.; Choo, S.W.; Choo, I.W.; Suh, Y.L.; Kim, S.M.; Kang, H.S.

    1999-01-01

    Objective. To analyze the findings of intramuscular vascular malformations of an extremity on MR imaging and to correlate these findings with histopathologic examination.Design and patients. The findings on MR imaging and the medical records of 14 patients with an intramuscular vascular malformation of the extremity were retrospectively studied. All patients underwent surgical excision. Diagnoses were based on the results of pathologic examination. Findings on MR imaging were noted and correlated with the histopathologic findings.Results. Intramuscular vascular malformations of an extremity showed multi-septate, honeycomb, or mixed appearance on MR imaging. Multi-septate areas correlated with dilated and communicating vascular spaces with flattened endothelium. Honeycomb areas corresponded to vascular spaces with inconspicuous small lumina and thickened vascular walls. Areas of increased signal intensity on T2-weighted images were found in all intramuscular vascular malformations. Infiltrative margins were more commonly seen in intramuscular lymphaticovenous malformations. Adherence to neurovascular structures and orientation of the lesion along the long axis of the affected muscle were more commonly seen in intramuscular venous malformations.Conclusions. Intramuscular vascular malformations showed either a multi-septate, honeycomb, or mixed appearance, reflecting the size of the vascular spaces and the thickness of the smooth muscles of the vessel walls. Prediction of the subtype of an intramuscular vascular malformation of an extremity on MR imaging seems to be difficult, although there are associated findings that may be helpful in the differential diagnosis of each subtype. (orig.)

  13. Compound Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Shlomo Shamai (Shitz

    2009-01-01

    Full Text Available This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom (s.d.o.f. are derived for the degraded case with one receiver. Schemes to achieve the s.d.o.f. for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable s.d.o.f. is given for the general case.

  14. Compound Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Kramer Gerhard

    2009-01-01

    Full Text Available Abstract This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom ( are derived for the degraded case with one receiver. Schemes to achieve the for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable is given for the general case.

  15. ATP Release Channels

    Directory of Open Access Journals (Sweden)

    Akiyuki Taruno

    2018-03-01

    Full Text Available Adenosine triphosphate (ATP has been well established as an important extracellular ligand of autocrine signaling, intercellular communication, and neurotransmission with numerous physiological and pathophysiological roles. In addition to the classical exocytosis, non-vesicular mechanisms of cellular ATP release have been demonstrated in many cell types. Although large and negatively charged ATP molecules cannot diffuse across the lipid bilayer of the plasma membrane, conductive ATP release from the cytosol into the extracellular space is possible through ATP-permeable channels. Such channels must possess two minimum qualifications for ATP permeation: anion permeability and a large ion-conducting pore. Currently, five groups of channels are acknowledged as ATP-release channels: connexin hemichannels, pannexin 1, calcium homeostasis modulator 1 (CALHM1, volume-regulated anion channels (VRACs, also known as volume-sensitive outwardly rectifying (VSOR anion channels, and maxi-anion channels (MACs. Recently, major breakthroughs have been made in the field by molecular identification of CALHM1 as the action potential-dependent ATP-release channel in taste bud cells, LRRC8s as components of VRACs, and SLCO2A1 as a core subunit of MACs. Here, the function and physiological roles of these five groups of ATP-release channels are summarized, along with a discussion on the future implications of understanding these channels.

  16. Clinical application of the amplatzer vascular plug in the embolization of vascular malformations associated with congenital heart diseasee

    International Nuclear Information System (INIS)

    Pan Xin; Wang Cheng; Lu Jing; Wu Weihua; Fang Weiyi

    2009-01-01

    Objective: To evaluate the clinical efficacy of percutaneous transcatheter embolization by using Amplatzer vascular plug (AVP) for the treatment of vascular malformations associated with congenital heart diseases. Methods: During the period of June 2006-June 2008, 12 patients with congenital heart disease accompanied by vascular malformations received transcatheter occlusion of the anomalous vessels with AVP. The vascular malformations included solitary or multiple saccular pulmonary arteriovenous malformation (n = 7), coronary artery fistula (n = 2) and major aortopulmonary collaterals concomitant with severe Fallot' s tetralogy (n = 3). All patients were screened with transthoracic echocardiography (TTE) and thoracic CT angiography (CTA), and all the diagnoses were confirmed by routine cardioangiography. Results: Transcatheter occlusion of vascular malformations with AVP was successfully accomplished in all 12 patients. An angiographic check immediately after the procedure showed that complete occlusion was obtained in all patients and no embolism,migration or residual shunt were seen. Sixteen anomalous vessels were occluded. The mean internal diameter of these vessels was (5.2 ± 1.9) mm,while the mean diameter of AVP used was (9.2 ± 2.4) mm. After the operation (mean 3 months), the follow-up echocardiography and/or thoracic CT angiography showed that in all patients the occlusion remained in satisfactory condition and no residual shunt was found. Conclusions: Percutaneous transcatheter closure of congenital vascular malformations with AVP is technically feasible and clinically effective, this treatment can markedly improve patient's living quality and it is well worth extending its clinical application. (authors)

  17. Information transfer through quantum channels

    International Nuclear Information System (INIS)

    Kretschmann, D.

    2007-01-01

    This PhD thesis represents work done between Aug. 2003 and Dec. 2006 in Reinhard F. Werner's quantum information theory group at Technische Universitaet Braunschweig, and Artur Ekert's Centre for Quantum Computation at the University of Cambridge. My thesis falls into the field of abstract quantum information theory. This work investigates both fundamental properties of quantum channels and their asymptotic capacities for classical as well as quantum information transfer. Stinespring's theorem is the basic structure theorem for quantum channels. It implies that every quantum channel can be represented as a unitary evolution on an enlarged system. In Ch. 3 we present a continuity theorem for Stinespring's representation: two quantum channels are similar if and only if it is possible to find unitary implementations that are likewise similar, with dimension-independent norm bounds. The continuity theorem allows to derive a formulation of the information-disturbance tradeoff in terms of quantum channels, and a continuity estimate for the no-broadcasting principle. In Ch. 4 we then apply the continuity theorem to give a strengthened no-go proof for quantum bit commitment, an important cryptographic primitive. This result also provides a natural characterization of those protocols that fall outside the standard setting of unconditional security, and thus may allow secure bit commitment. We present a new such protocol whose security relies on decoherence in the receiver's lab. Ch. 5 reviews the capacities of quantum channels for the transfer of both classical and quantum information, and investigates several variations in the notion of channel capacity. Memory effects are then investigated in detail in Ch. 6. We advertise a model which is sufficiently general to encompass all causal automata: every quantum process in which the outputs up to any given time t do not depend on the inputs at times t'>t can be represented as a concatenated memory channel. We then explain how

  18. Information transfer through quantum channels

    Energy Technology Data Exchange (ETDEWEB)

    Kretschmann, D.

    2007-03-12

    This PhD thesis represents work done between Aug. 2003 and Dec. 2006 in Reinhard F. Werner's quantum information theory group at Technische Universitaet Braunschweig, and Artur Ekert's Centre for Quantum Computation at the University of Cambridge. My thesis falls into the field of abstract quantum information theory. This work investigates both fundamental properties of quantum channels and their asymptotic capacities for classical as well as quantum information transfer. Stinespring's theorem is the basic structure theorem for quantum channels. It implies that every quantum channel can be represented as a unitary evolution on an enlarged system. In Ch. 3 we present a continuity theorem for Stinespring's representation: two quantum channels are similar if and only if it is possible to find unitary implementations that are likewise similar, with dimension-independent norm bounds. The continuity theorem allows to derive a formulation of the information-disturbance tradeoff in terms of quantum channels, and a continuity estimate for the no-broadcasting principle. In Ch. 4 we then apply the continuity theorem to give a strengthened no-go proof for quantum bit commitment, an important cryptographic primitive. This result also provides a natural characterization of those protocols that fall outside the standard setting of unconditional security, and thus may allow secure bit commitment. We present a new such protocol whose security relies on decoherence in the receiver's lab. Ch. 5 reviews the capacities of quantum channels for the transfer of both classical and quantum information, and investigates several variations in the notion of channel capacity. Memory effects are then investigated in detail in Ch. 6. We advertise a model which is sufficiently general to encompass all causal automata: every quantum process in which the outputs up to any given time t do not depend on the inputs at times t'>t can be represented as a concatenated memory

  19. Interventional MR: vascular applications.

    Science.gov (United States)

    Smits, H F; Bos, C; van der Weide, R; Bakker, C J

    1999-01-01

    Three strategies for visualisation of MR-dedicated guidewires and catheters have been proposed, namely active tracking, the technique of locally induced field inhomogeneity and passive susceptibility-based tracking. In this article the pros and cons of these techniques are discussed, including the development of MR-dedicated guidewires and catheters, scan techniques, post-processing tools, and display facilities for MR tracking. Finally, some of the results obtained with MR tracking are discussed.

  20. Vascular neurocognitive disorders and the vascular risk factors

    Directory of Open Access Journals (Sweden)

    Carmen V. Albu

    2018-04-01

    Full Text Available Dementias are clinical neurodegenerative diseases characterized by permanent and progressive transformation of cognitive functions such as memory, learning capacity, attention, thinking, language, passing judgments, calculation or orientation. Dementias represent a relatively frequent pathology, encountered at about 10% of the population of 65-year olds and 20% of the population of 80-year olds. This review presents the main etiological forms of dementia, which include Alzheimer form of dementia, vascular dementia, dementia associated with alpha-synucleionopathies, and mixed forms. Regarding vascular dementia, the risk factors are similar to those for an ischemic or hemorrhagic cerebrovascular accident: arterial hypertension, diabetes mellitus, dyslipidemia, smoking, obesity, age, alcohol consumption, cerebral atherosclerosis/ arteriosclerosis. Several studies show that efficient management of the vascular risk factors can prevent the expression and/ or progression of dementia. Thus, lifestyle changes such as stress reduction, regular physical exercise, decreasing dietary fat, multivitamin supplementation, adequate control of blood pressure and serum cholesterol, and social integration and mental stimulation in the elderly population are important factors in preventing or limiting the symptoms of dementia, a disease with significant individual, social, and economic implications.

  1. Effective IPTV channel management method over heterogeneous environments

    Science.gov (United States)

    Joo, Hyunchul; Lee, Dai-boong; Song, Hwangjun

    2007-09-01

    This paper presents an effective IPTV channel management method using SVC (scalable video coding) that considers concurrently both channel zapping time and network utilization. A broadcasting channel is encoded in two-layered bitstream (base-layer channel and enhancement-layer channel) to supply for heterogeneous environments. The proposed algorithm locates only a limited numbers of base-layer channels close to users to reduce the network delay part of channel zapping time and adjusts the length of GOP (group of picture) into each base-layer channel to decrease the video decoding delay part of channel zapping time, which are performed based on user's channel preference information. Finally, the experimental results are provided to show the performance of the proposed schemes.

  2. Malaria and Vascular Endothelium

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Aristóteles Comte Filho de, E-mail: aristoteles.caf@gmail.com [Universidade Federal do Amazonas, Manaus, AM (Brazil); Lacerda, Marcus Vinícius Guimarães de [Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, AM (Brazil); Okoshi, Katashi; Okoshi, Marina Politi [Faculdade de Medicina de Botucatu (Unesp), Botucatu, SP (Brazil)

    2014-08-15

    Involvement of the cardiovascular system in patients with infectious and parasitic diseases can result from both intrinsic mechanisms of the disease and drug intervention. Malaria is an example, considering that the endothelial injury by Plasmodium-infected erythrocytes can cause circulatory disorders. This is a literature review aimed at discussing the relationship between malaria and endothelial impairment, especially its effects on the cardiovascular system. We discuss the implications of endothelial aggression and the interdisciplinarity that should guide the malaria patient care, whose acute infection can contribute to precipitate or aggravate a preexisting heart disease.

  3. Malaria and Vascular Endothelium

    International Nuclear Information System (INIS)

    Alencar, Aristóteles Comte Filho de; Lacerda, Marcus Vinícius Guimarães de; Okoshi, Katashi; Okoshi, Marina Politi

    2014-01-01

    Involvement of the cardiovascular system in patients with infectious and parasitic diseases can result from both intrinsic mechanisms of the disease and drug intervention. Malaria is an example, considering that the endothelial injury by Plasmodium-infected erythrocytes can cause circulatory disorders. This is a literature review aimed at discussing the relationship between malaria and endothelial impairment, especially its effects on the cardiovascular system. We discuss the implications of endothelial aggression and the interdisciplinarity that should guide the malaria patient care, whose acute infection can contribute to precipitate or aggravate a preexisting heart disease

  4. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume...... but are also essential for a number of physiological processes such as proliferation, controlled cell death, migration and endocrinology. The thesis have been focusing on two Channels, namely the swelling activated Cl- channel (ICl, swell) and the transient receptor potential Vanilloid (TRPV4) channel. I: Cl......- serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...

  5. An Analysis of Responses to Defibrotide in the Pulmonary Vascular Bed of the Cat.

    Science.gov (United States)

    Kaye, Alan D; Skonieczny, Brendan D; Kaye, Aaron J; Harris, Zoey I; Luk, Eric J

    2016-01-01

    Defibrotide is a polydisperse mixture of single-stranded oligonucleotides with many pharmacologic properties and multiple actions on the vascular endothelium. Responses to defibrotide and other vasodepressor agents were evaluated in the pulmonary vascular bed of the cat under conditions of controlled pulmonary blood flow and constant left atrial pressure. Lobar arterial pressure was increased to a high steady level with the thromboxane A2 analog U-46619. Under increased-tone conditions, defibrotide caused dose-dependent decreases in lobar arterial pressure without altering systemic arterial and left atrial pressures. Responses to defibrotide were significantly attenuated after the administration of the cyclooxygenase inhibitor sodium meclofenamate. Responses to defibrotide were also significantly attenuated after the administration of both the adenosine 1 and 2 receptor antagonists 8-cyclopentyl-1,3-dimethylxanthine and 8-(3-chlorostyryl)caffeine. Responses to defibrotide were not altered after the administration of the vascular selective adenosine triphosphate-sensitive potassium channel blocker U-37883A, or after the administration of the nitric oxide synthase inhibitor L-N-(1-iminoethyl)-ornithine. These data show that defibrotide has significant vasodepressor activity in the pulmonary vascular bed of the cat. They also suggest that pulmonary vasodilator responses to defibrotide are partially dependent on both the activation of the cyclooxygenase enzyme and adenosine 1 and 2 receptor pathways and independent of the activation of adenosine triphosphate-sensitive potassium channels or the synthesis of nitric oxide in the pulmonary vascular bed of the cat.

  6. Hematological and vascular disorders

    International Nuclear Information System (INIS)

    Rowe, L.J.; Yochum, T.R.

    1987-01-01

    Numerous blood-related disorders will demonstrate skeletal alterations. These include various anemias, leukemias, lymphomas, and clotting-deficient diseases (hemophilia). Of all the various types of anemias only those that are chronic and severe will result in radiographically visible osseous changes. The skeletal alterations which are observed are invariably related to the direct effects on the bone marrow or are secondary to the inherent complications of the disease. The most notable osseous changes are seen in the congenital hemolytic anemias, especially thalassemia (Cooley's anemia), sickle cell anemia, and hereditary spherocytosis. Chronic iron deficiency anemia produces very minor skeletal changes, usually isolated to the skull. Leukemia demonstrates characteristic changes largely dependent on age. Hemophilia primarily alters joint function due to recurrent intraarticular hemorrhage. This chapter discusses blood-related disorders that affect the bones

  7. Optimal processing of reversible quantum channels

    Energy Technology Data Exchange (ETDEWEB)

    Bisio, Alessandro, E-mail: alessandro.bisio@unipv.it [QUIT Group, Dipartimento di Fisica, INFN Sezione di Pavia, via Bassi 6, 27100 Pavia (Italy); D' Ariano, Giacomo Mauro; Perinotti, Paolo [QUIT Group, Dipartimento di Fisica, INFN Sezione di Pavia, via Bassi 6, 27100 Pavia (Italy); Sedlák, Michal [Department of Optics, Palacký University, 17. Listopadu 1192/12, CZ-771 46 Olomouc (Czech Republic); Institute of Physics, Slovak Academy of Sciences, Dúbravská Cesta 9, 845 11 Bratislava (Slovakia)

    2014-05-01

    We consider the general problem of the optimal transformation of N uses of (possibly different) unitary channels to a single use of another unitary channel in any finite dimension. We show how the optimal transformation can be fully parallelized, consisting in a preprocessing channel followed by a parallel action of all the N unitaries and a final postprocessing channel. Our techniques allow to achieve an exponential reduction in the number of the free parameters of the optimization problem making it amenable to an efficient numerical treatment. Finally, we apply our general results to find the analytical solution for special cases of interest like the cloning of qubit phase gates.

  8. Measuring Balance Across Multiple Radar Receiver Channels.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W.; Bickel, Douglas L.

    2018-03-01

    When radar receivers employ multiple channels, the general intent is for the receive channels to be as alike as possible, if not as ideal as possible. This is usually done via prudent hardware design, supplemented by system calibration. Towards this end, we require a quality metric for ascertaining the goodness of a radar channel, and the degree of match to sibling channels. We propose a relevant and useable metric to do just that. Acknowledgements This report was the result of an unfunded research and development activity.

  9. Electron angular distribution axial channeling

    International Nuclear Information System (INIS)

    Khokonov, A.Kh.; Khokonov, M.Kh.

    1989-01-01

    Angular distributions of ultra-relativistic electrons are calculated in the assumption about presence of statistical equilibrium. Analysis is based on numerical solution of Fokker-Planck type kinetic equation. It is shown that in contrast to case of amorphous medium, the multiple scattering at axial channeling of negative particles results in self-focusing of the initial beam particles and due to it number of electrons moving at an angles to the chain, which are smaller, than critical angle of channeling, may increase by several times as compared to the initial one

  10. Pannexin-1 channels in epilepsy.

    Science.gov (United States)

    Aquilino, Mark S; Whyte-Fagundes, Paige; Zoidl, Georg; Carlen, Peter L

    2017-09-05

    Pannexin-1 (Panx1) expression is raised in several animal seizure models and in resected human epileptic brain tissue, suggesting relevance to epilepsy. Multiple factors that are characteristic of seizures are thought to regulate Panx1 channel opening, including elevated levels of extracellular K + . Panx1, when open, 1) releases ATP, glutamate, and other metabolites into the extracellular medium, and 2) may depolarize the membrane due to a channel reversal potential around 0mV. Resultant ATP release from stimulated Panx1 can activate purinergic receptors, including P2X7 receptors. Glutamate and other signaling molecules released by Panx1 opening may have both excitatory and inhibitory actions on seizure generation. This review examines the critical and complex roles of Panx1 channels in epilepsy, which could provide a basis for future therapeutics. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. HIPPI and Fibre Channel

    International Nuclear Information System (INIS)

    Tolmie, D.E.

    1992-01-01

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background

  12. Nuclear reactor coolant channels

    International Nuclear Information System (INIS)

    Macbeth, R.V.

    1978-01-01

    Reference is made to coolant channels for pressurised water and boiling water reactors and the arrangement described aims to improve heat transfer between the fuel rods and the coolant. Baffle means extending axially within the channel are provided and disposed relative to the fuel rods so as to restrict flow oscillations occurring within the coolant from being propagated transversely to the axis of the channel. (UK)

  13. Amplatzer vascular plugs in congenital cardiovascular malformations

    Directory of Open Access Journals (Sweden)

    Parag Barwad

    2013-01-01

    Full Text Available Background: Amplatzer vascular plugs (AVPs are devices ideally suited to close medium-to-large vascular communications. There is limited published literature regarding the utility of AVPs in congenital cardiovascular malformations (CCVMs. Aims: To describe the use of AVPs in different CCVMs and to evaluate their safety and efficacy. Materials and Methods: All patients who required an AVP for the closure of CCVM were included in this retrospective review of our catheterization laboratory data. The efficacy and safety of AVPs are reported. Results: A total of 39 AVPs were implanted in 31 patients. Thirteen (33% were AVP type I and 23 (59% were AVP type II. AVP type III were implanted in two patients and type IV in one patient. The major indications for their use included closure of pulmonary arteriovenous malformation (AVM (n = 7, aortopulmonary collaterals (n = 7, closure of a patent Blalock-Taussig shunt (n = 5, systemic AVM (n = 5, coronary AVM (n = 4, patent ductus arteriosus (PDA (n = 3, pulmonary artery aneurysms (n = 3, and venovenous collaterals (n = 2. Deployment of the AVP was done predominantly via the 5 - 7F Judkin′s right coronary guide catheter. Overall 92% of the AVPs could be successfully deployed and resulted in occlusion of the target vessel in all cases, within 10 minutes. No procedure-related or access site complication occurred. Conclusions: AVPs are versatile, easy to use, and effective devices to occlude the vascular communications in a variety of settings. AVP II is especially useful in the closure of tubular structures with a high flow.

  14. [Menopause: Hypertension and vascular disease].

    Science.gov (United States)

    Zilberman, J M

    Hypertension is the main cardiovascular risk factor affecting 25% of women. Hormone changes and hypertension after menopause may lead to higher target organ damage and cardiovascular disease such as increased arterial stiffness, coronary diseases, chronic heart failure and stroke. The physiopathological mechanisms involved in the development of hypertension and cardiovascular diseases in menopausal women are controversial. There are pharmacokinetic and pharmacodynamic differences in both sexes, the women have more coughing when using the converting-enzyme inhibitors, more cramps when using thiazide diuretics and more oedema in the inferior limbs when using calcium antagonists. The aim of this review is to analyse possible physiopathological mechanisms involved in hypertension after menopause and to gain a better understanding of the biological effects mediated by vascular ageing in women when the level of oestrogen protective effect decreases over the vascular system. Copyright © 2017 SEH-LELHA. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Quantum incompatibility of channels with general outcome operator algebras

    Science.gov (United States)

    Kuramochi, Yui

    2018-04-01

    A pair of quantum channels is said to be incompatible if they cannot be realized as marginals of a single channel. This paper addresses the general structure of the incompatibility of completely positive channels with a fixed quantum input space and with general outcome operator algebras. We define a compatibility relation for such channels by identifying the composite outcome space as the maximal (projective) C*-tensor product of outcome algebras. We show theorems that characterize this compatibility relation in terms of the concatenation and conjugation of channels, generalizing the recent result for channels with quantum outcome spaces. These results are applied to the positive operator valued measures (POVMs) by identifying each of them with the corresponding quantum-classical (QC) channel. We also give a characterization of the maximality of a POVM with respect to the post-processing preorder in terms of the conjugate channel of the QC channel. We consider another definition of compatibility of normal channels by identifying the composite outcome space with the normal tensor product of the outcome von Neumann algebras. We prove that for a given normal channel, the class of normally compatible channels is upper bounded by a special class of channels called tensor conjugate channels. We show the inequivalence of the C*- and normal compatibility relations for QC channels, which originates from the possibility and impossibility of copying operations for commutative von Neumann algebras in C*- and normal compatibility relations, respectively.

  16. New Channels, New Possibilities

    DEFF Research Database (Denmark)

    Pieterson, Willem; Ebbers, Wolfgang; Østergaard Madsen, Christian

    2017-01-01

    In this contribution we discuss the characteristics of what we call the fourth generation of public sector service channels: social robots. Based on a review of relevant literature we discuss their characteristics and place into multi-channel models of service delivery. We argue that social robots......-channel models of service delivery. This is especially relevant given the current lack of evaluations of such models, the broad range of channels available, and their different stages of deployment at governments around the world. Nevertheless, social robots offer an potentially very relevant addition...

  17. Calcium Channel Blockers

    Science.gov (United States)

    ... Certain calcium channel blockers interact with grapefruit products. Kaplan NM, et al. Treatment of hypertension: Drug therapy. In: Kaplan's Clinical Hypertension. 11th ed. Philadelphia, Pa.: Wolters Kluwer ...

  18. A channel profile analyser

    International Nuclear Information System (INIS)

    Gobbur, S.G.

    1983-01-01

    It is well understood that due to the wide band noise present in a nuclear analog-to-digital converter, events at the boundaries of adjacent channels are shared. It is a difficult and laborious process to exactly find out the shape of the channels at the boundaries. A simple scheme has been developed for the direct display of channel shape of any type of ADC on a cathode ray oscilliscope display. This has been accomplished by sequentially incrementing the reference voltage of a precision pulse generator by a fraction of a channel and storing ADC data in alternative memory locations of a multichannel pulse height analyser. Alternative channels are needed due to the sharing at the boundaries of channels. In the flat region of the profile alternate memory locations are channels with zero counts and channels with the full scale counts. At the boundaries all memory locations will have counts. The shape of this is a direct display of the channel boundaries. (orig.)

  19. Functional transient receptor potential vanilloid 1 and transient receptor potential vanilloid 4 channels along different segments of the renal vasculature

    DEFF Research Database (Denmark)

    Chen, L; Kaßmann, M; Sendeski, M

    2015-01-01

    with functional TRPV1 having a narrow, discrete distribution in the resistance vasculature and TRPV4 having more universal, widespread distribution along different vascular segments. We suggest that TRPV1/4 channels are potent therapeutic targets for site-specific vasodilation in the kidney.......AIM: Transient receptor potential vanilloid 1 (TRPV1) and vanilloid 4 (TRPV4) cation channels have been recently identified to promote endothelium-dependent relaxation of mouse mesenteric arteries. However, the role of TRPV1 and TRPV4 in the renal vasculature is largely unknown. We hypothesized...... that TRPV1/4 plays a role in endothelium-dependent vasodilation of renal blood vessels. METHODS: We studied the distribution of functional TRPV1/4 along different segments of the renal vasculature. Mesenteric arteries were studied as control vessels. RESULTS: The TRPV1 agonist capsaicin relaxed mouse...

  20. Vascular diagnostics for Raynaud's phenomenon

    Directory of Open Access Journals (Sweden)

    Dinsdale G

    2014-10-01

    Full Text Available Graham Dinsdale, Ariane L Herrick Centre for Musculoskeletal Research, Institute of Inflammation and Repair, Salford Royal NHS Foundation Trust, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK Abstract: Raynaud's phenomenon (RP is common, and in most patients is primary (idiopathic when due to reversible vasospasm and does not progress to irreversible tissue injury. However, in those patients for whom RP is secondary to an underlying disease (eg, systemic sclerosis or atherosclerosis, progression to digital ulceration or critical ischemia can occur. Therefore, the key question for the clinician is “Why does this patient have RP?” Vascular diagnostics play a key role in answering this. In this review, we firstly discuss the different vascular investigations relevant to clinical practice: nail fold capillaroscopy (including the different methodologies for examining the nail fold capillaries, and the role of capillaroscopy in helping to differentiate between primary and systemic sclerosis-related RP, thermography (available in specialist centers, and evaluation of large vessel disease (for example, due to atherosclerosis. We then discuss research tools, mainly laser Doppler methods, including laser Doppler imaging and laser speckle contrast imaging. These are commercially available as complete imaging systems and are (relatively easy to use. The main current goal in vascular imaging research is to validate these novel state-of-the-art techniques as outcome measures of digital vascular disease, and then apply them in early and later phase studies of new treatment approaches, thus facilitating drug development programs. Keywords: Raynaud's phenomenon, systemic sclerosis, nail fold capillaroscopy, thermography, laser Doppler, angiography

  1. Sorting out river channel patterns

    NARCIS (Netherlands)

    Kleinhans, M.G.

    2010-01-01

    Rivers self-organize their pattern/planform through feedbacks between bars, channels, floodplain and vegetation, which emerge as a result of the basic spatial sorting process of wash load sediment and bed sediment. The balance between floodplain formation and destruction determines the width and

  2. Rectal and splenic vascular malformation in klippel trenaunay weber syndrome: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ha Youn; Chang, Yun Woo; Lee, Dong Hwan [Soonchunhyang Univ. Hospital, Seoul (Korea, Republic of)

    2012-10-15

    Klippel Trenaunay Weber syndrome (KTWS) is a rare congenital disorder, characterized by a cutaneous vascular nevus of the involved extremity, vascular malformations, bone and soft tissue hypertrophy of the extremity. We present the case of an 18 year old female patient with KTWS, showing a marked rectosigmoid wall thickening and phlebolith, and also variable sized cystic masses in the spleen, as a result of vascular malformations.

  3. Vascular injury is associated with increased mortality in winter sports trauma.

    Science.gov (United States)

    Eun, John C; Bronsert, Michael; Hansen, Kristine; Moulton, Steven L; Jazaeri, Omid; Nehler, Mark; Greenberg, Joshua I

    2015-01-01

    Trauma is the leading cause of injury and death for individuals aged 1-44 years. Up to 8% of the US population participates in winter sports, and although vascular injuries are uncommon in these activities, little is published in this area. We sought to identify the incidence, injury patterns, and outcomes of vascular injuries resulting from winter sports trauma. Patients with winter sports trauma and the subset with vascular injuries were identified by accessing the National Trauma Data Bank querying years 2007-2010. Patients with and without vascular injuries were then compared. Admission variables included transport time, emergency department hypotension (systolic blood pressure Injury Severity Score ≥ 25, fractures, solid organ injury, and vascular injury. Outcomes were analyzed and associations with vascular injuries were determined. A total of 2,298 patients were identified with winter sports-related trauma and 28 (1.2%) had associated vascular injuries. Overall, the top 3 injuries were head trauma (16.7%), thoracic vertebral fractures (5.5%), and lumbar vertebral fractures (5.1%). The most common associated vascular injures were to the popliteal artery (17.7%), splenic artery (14.7%), and brachial blood vessels (14.7%). In the entire cohort, 1 patient (0.04%) suffered an amputation and 15 patients (0.7%) died. There were no amputations in the vascular injury group. Mortality was 0.6% in patients without a vascular injury compared with 7.1% of those with a vascular injury (P = 0.01). Although vascular injury is an uncommon associated finding in winter sports trauma, it is associated with a significant increase in mortality. These findings highlight the need for rapid identification of traumatic vascular injuries, which predicts worse overall outcomes in this patient population. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Vascular injuries of the upper extremity Lesões vasculares de membros superiores

    Directory of Open Access Journals (Sweden)

    Raafat Shalabi

    2006-12-01

    Full Text Available OBJECTIVE: This study analyzes the causes of injuries, presentations, surgical approaches, outcome and complications of vascular trauma of the upper limbs, in spite of limited hospital resources. METHODS: A 5-year retrospective analysis. From 01/01/2001 to 31/12/2005, 165 patients were operated for vascular injuries at King Fahd Hospital, Medina, Saudi Arabia. Of all peripheral vascular trauma patients (115, upper limb trauma was present in 58. Diagnosis was made by physical examination and hand-held Doppler alone or in combination with Doppler scan/angiography. Primary vascular repair was performed whenever possible; otherwise, the interposition vein graft was used. Fasciotomy was considered when required. Patients with unsalvageable lower extremity injury requiring primary amputation were excluded from the study. RESULTS: Fifty patients were male (86% and eight were female (14%, aged between 2.5-55 years (mean 23 years. Mean duration of presentation was 8 h after the injury. The most common etiological factor was road traffic accidents, accounting for 50.5% in the blunt trauma group and 33% among all penetrating and stab wound injuries. Incidence of concomitant orthopedic injuries was very high in our study (51%. The brachial artery was the most affected (51%. Interposition vein grafts were used in 53% of the cases. Limb salvage rate was 100%. CONCLUSION: Patients who suffer vascular injuries of the upper extremities should be transferred to vascular surgery centers as soon as possible. Decisive management of peripheral vascular trauma will maximize patient survival and limb salvage. Priorities must be established in the management of associated injuries, and delay must be avoided when ischemic changes are present.OBJETIVO: Este estudo analisa as causas de lesões, apresentação, abordagens cirúrgicas, desfechos e complicações do trauma vascular de membros superiores, apesar de recursos hospitalares limitados. MÉTODOS: An

  5. Sediment sorting at a side channel bifurcation

    Science.gov (United States)

    van Denderen, Pepijn; Schielen, Ralph; Hulscher, Suzanne

    2017-04-01

    Side channels have been constructed to reduce the flood risk and to increase the ecological value of the river. In various Dutch side channels large aggradation in these channels occurred after construction. Measurements show that the grain size of the deposited sediment in the side channel is smaller than the grain size found on the bed of the main channel. This suggest that sorting occurs at the bifurcation of the side channel. The objective is to reproduce with a 2D morphological model the fining of the bed in the side channel and to study the effect of the sediment sorting on morphodynamic development of the side channel. We use a 2D Delft3D model with two sediment fractions. The first fraction corresponds with the grain size that can be found on the bed of the main channel and the second fraction corresponds with the grain size found in the side channel. With the numerical model we compute several side channel configurations in which we vary the length and the width of the side channel, and the curvature of the upstream channel. From these computations we can derive the equilibrium state and the time scale of the morphodynamic development of the side channel. Preliminary results show that even when a simple sediment transport relation is used, like Engelund & Hansen, more fine sediment enters the side channel than coarse sediment. This is as expected, and is probably related to the bed slope effects which are a function of the Shields parameter. It is expected that by adding a sill at the entrance of the side channel the slope effect increases. This might reduce the amount of coarse sediment which enters the side channel even more. It is unclear whether the model used is able to reproduce the effect of such a sill correctly as modelling a sill and reproducing the correct hydrodynamic and morphodynamic behaviour is not straightforward in a 2D model. Acknowledgements: This research is funded by STW, part of the Dutch Organization for Scientific Research under

  6. Longitudinal visualization of vascular occlusion, reperfusion, and remodeling in a zebrafish model of retinal vascular leakage using OCT angiography

    Science.gov (United States)

    Spitz, Kathleen; Bozic, Ivan; Desai, Vineet; Rao, Gopikrishna M.; Pollock, Lana M.; Anand-Apte, Bela; Tao, Yuankai K.

    2017-02-01

    Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are two of the leading causes of blindness and visual impairment in the world. Neovascularization results in severe vision loss in DR and AMD and, thus, there is an unmet need to identify mechanisms of pathogenesis and novel anti-angiogenic therapies. Zebrafish is a leading model organism for studying human disease pathogenesis, and the highly conserved drug activity between zebrafish and humans and their ability to readily absorb small molecules dissolved in water has benefited pharmaceutical discovery. Here, we use optical coherence tomography (OCT) and OCT angiography (OCT-A) to perform noninvasive, in vivo retinal imaging in a zebrafish model of vascular leakage. Zebrafish were treated with diethylaminobenzaldehyde (DEAB) to induce vascular leakage and imaged with OCT and OCT-A at six time points over two weeks: baseline one day before treatment and one, three, six, eight, and ten days post treatment. Longitudinal functional imaging showed significant vascular response immediately after DEAB treatment. Observed vascular changes included partial or complete vascular occlusion immediately after treatment and reperfusion during a two-week period. Increased vascular tortuosity several days post treatment indicated remodeling, and bifurcations and collateral vessel formation were also observed. In addition, significant treatment response variabilities were observed in the contralateral eye of the same animal. Anatomical and functional normalization was observed in most animals by ten days post treatment. These preliminary results motivate potential applications of OCT-A as a tool for studying pathogenesis and therapeutic screening in zebrafish models of retinal vascular disease.

  7. Endothelial Small- and Intermediate-Conductance KCa Channels

    DEFF Research Database (Denmark)

    Wulff, Heike; Köhler, Ralf

    2013-01-01

    ABSTRACT:: Most cardiovascular researchers are familiar with intermediate-conductance KCa3.1 and small-conductance KCa2.3 channels because of their contribution to endothelium-derived hyperpolarization (EDH). However, to immunologists and neuroscientists these channels are primarily known...... for their role in lymphocyte activation and neuronal excitability. KCa3.1 is involved in the proliferation and migration of T cells, B cell, mast cells, macrophages, fibroblasts and dedifferentiated vascular smooth muscle cells and is, therefore, being pursued as a potential target for use in asthma...

  8. CHANNELING OF B-IONS IN SILICON

    NARCIS (Netherlands)

    VOS, M; MITCHELL, [No Value; SMULDERS, PJM

    We present new results on the channeling of B ions in Si crystals. Standard surface barrier detectors have been used to record energy spectra for B ions backscattered from the near surface (approximately 1500 angstrom) of a silicon crystal, under perfect, and near axial and planar channeling

  9. Channel and Timeslot Co-Scheduling with Minimal Channel Switching for Data Aggregation in MWSNs

    Directory of Open Access Journals (Sweden)

    Sanggil Yeoum

    2017-05-01

    Full Text Available Collision-free transmission and efficient data transfer between nodes can be achieved through a set of channels in multichannel wireless sensor networks (MWSNs. While using multiple channels, we have to carefully consider channel interference, channel and time slot (resources optimization, channel switching delay, and energy consumption. Since sensor nodes operate on low battery power, the energy consumed in channel switching becomes an important challenge. In this paper, we propose channel and time slot scheduling for minimal channel switching in MWSNs, while achieving efficient and collision-free transmission between nodes. The proposed scheme constructs a duty-cycled tree while reducing the amount of channel switching. As a next step, collision-free time slots are assigned to every node based on the minimal data collection delay. The experimental results demonstrate that the validity of our scheme reduces the amount of channel switching by 17.5%, reduces energy consumption for channel switching by 28%, and reduces the schedule length by 46%, as compared to the existing schemes.

  10. A linearization of quantum channels

    Science.gov (United States)

    Crowder, Tanner

    2015-06-01

    Because the quantum channels form a compact, convex set, we can express any quantum channel as a convex combination of extremal channels. We give a Euclidean representation for the channels whose inverses are also valid channels; these are a subset of the extreme points. They form a compact, connected Lie group, and we calculate its Lie algebra. Lastly, we calculate a maximal torus for the group and provide a constructive approach to decomposing any invertible channel into a product of elementary channels.

  11. Experience of vascular trauma in a tertiary care hospital

    International Nuclear Information System (INIS)

    Imtiaz, N.

    2010-01-01

    To highlight the presentation and management of various vascular injuries and their outcome. Thirty nine cases of vascular trauma were referred to vascular surgeon CMH Rawalpindi, in the above mentioned period. These cases were evaluated for mechanism of injury, age, gender and time of presentation. Out of these, only thirty cases were found suitable for surgical intervention. These thirty cases were evaluated for site of vascular injury, associated injuries, type of surgery performed and the outcome. Blunt trauma was the predominant cause of vascular injuries in our study 16/39 (41%). Fourteen cases (35.8%) had gun shot wounds. Only thirty patients (76.9 %) underwent various surgical procedures. Primary end to end anastomosis was possible in only 5/30 cases (16.6%) while reversed venous graft was used in 13/30 cases (43.3%). Wound infection occurred in 2/30(6.6%) cases out of which 1 case (3.3%) ultimately had an amputation. The time period between injury and surgical intervention ranged between 1 to 20 hours for most of the vascular injuries while delayed presentation in the form of traumatic arteriovenous fistula or pseudoaneurysm was between 48 hours to 3 months. There are reasonable numbers of vascular trauma cases being referred to a tertiary care hospital. Most of these cases reach us quite late due to unnecessary investigations, delayed referral and transportation. Early intervention and revascularization definitely reduces amputation and complication rate. All gunshot wounds not only require thorough surrounding soft tissue debridement but also liberal excision of traumatised vessel itself, resulting in interposition graft repair. (author)

  12. Methane dynamics in Northern Wetlands: Significance of vascular plants

    Energy Technology Data Exchange (ETDEWEB)

    Joabsson, Anna

    2001-09-01

    The studies presented illustrate several different aspects of the impact of vascular plants on methane emissions from northern natural wetlands. The subject has been approached on different scales, ranging from the study of microbial substrates in the vicinity of a single plant root, to an attempt to extrapolate some of the results to the entire northern hemisphere north of 50 meridian. The main overall conclusions from the papers are that vascular plants affect net methane emissions 1) by offering an efficient route of transport to the atmosphere so that methane oxidation in oxic surface soils is avoided, and 2) by being sources of methanogenic substrate. The degree to which vascular wetland plants affect methane emissions seems to be dependent on species-specific differences in both the capacity to act as gas conduits and the exudation of labile carbon compounds to the soil. An intimate coupling between vascular plant production and methane emission was found in an Arctic tundra wetland, although other environmental variables (water table, temperature) also contributed significantly to the explained variation in methane exchange. Studies of vascular plant extidation of organic acids suggest that the available pool of methanogenic substrates is both qualitatively and quantitatively correlated to vascular plant production (photosynthetic rate). On global scales, vascular plant production as a single factor does not seem to be sufficient to explain the majority of variation in methane flux patterns. Based on comparable experiments at five different sites in the northwestern Eurasian and Greenlandic North, we suggest that mean seasonal soil temperature is the best predictor of methane exchange on broad spatial and temporal scales.

  13. Neuropsychiatric symptoms in Vascular Cognitive Impairment: A systematic review

    Directory of Open Access Journals (Sweden)

    Chan Tiel

    Full Text Available Neuropsychiatric symptoms or Behavioral and Psychological Symptoms of Dementia (BPSD are common and invariably appear at some point during the course of the disease, mediated both by cerebrovascular disease and neurodegenerative processes. Few studies have compared the profiles of BPSD in Vascular Cognitive Impairment (VCI of different subtypes (subcortical or cortical and clinical stages (Vascular Cognitive Impairment No Dementia [VaCIND] and Vascular Dementia [VaD].Objective:To review the BPSD associated with different subtypes and stages of VCI using the Neuropsychiatric Inventory (NPI.Methods:Medline, Scielo and Lilacs databases were searched for the period January 2000 to December 2014, with the key words: "BPSD AND Vascular Dementia, "NPI AND Vascular Dementia" and "NPI AND VCI. Qualitative analysis was performed on studies evaluating BPSD in VCI, using the Neuropsychiatric Inventory (NPI.Results:A total of 82 studies were retrieved of which 13 were eligible and thus included. Among the articles selected, 4 compared BPSD in Subcortical Vascular Dementia (SVaD versus Cortical-Subcortical Vascular Dementia (CSVaD, 3 involved comparisons between SVaD and VaCIND, 1 study analyzed differences between CSVaD and VaCIND, while 5 studies assessed BPSD in CSVaD. Subcortical and Cortical-Subcortical VaD were associated predominantly with Apathy and Depression. VaCIND may present fewer behavioral symptoms than VaD.Conclusion:The profile of BPSD differs for different stages of VCI. Determining the most prevalent BPSD in VCI subtypes might be helpful for improving early diagnosis and management of these symptoms.

  14. Terror attacks increases the risk of vascular injuries

    Directory of Open Access Journals (Sweden)

    Eitan eHeldenberg

    2014-05-01

    Full Text Available Objectives: Extensive literature exists about military trauma as opposed to the very limited literature regarding terror-related civilian trauma. However, terror-related vascular trauma (VT, as a unique type of injury, is yet to be addressed.Methods: A retrospective analysis of the Israeli National Trauma Registry was performed. All patients in the registry from 09/2000 to 12/2005 were included. The subgroup of patients with documented vascular trauma (VT (N=1,545 was analyzedand further subdivided into those suffering from Terror-related Vascular Trauma (TVT and Non-Terror related Vascular Trauma (NTVT. Both groups were analyzed according to mechanism of trauma, type and severity of injury and treatment.Results: Out of 2,446 terror related trauma admissions 243 sustained TVT (9.9% compared to 1302 VT patients from Non Terror trauma (1.1%. TVT injuries tend to be more complex and most patients were operated on. ICU admissions and hospitallength of stay was higher in the TVT group. Penetrating trauma was the prominent cause of injury among the TVT group. TVT group had a higher proportion of patients with severe injuries (ISS>16 and mortality. Thorax injuries were more frequent in the TVT group. Extremity injuries were the most prevalent vascular injuries in both groups; however NTVT group had more upper extremity injuries, while the TVT group had significantly more lower extremity injuries.Conclusion: Vascular injuries are remarkably more common among terror attack victims than among non-terror trauma victims and the injuries of terror casualties tend to be more complex. The presence of a vascular surgeon will ensure a comprehensive clinical care.

  15. [Mechanism of losartan suppressing vascular calcification in rat aortic artery].

    Science.gov (United States)

    Shao, Juan; Wu, Panfeng; Wu, Jiliang; Li, Mincai

    2016-08-01

    Objective To investigate the effect of the angiotensin II receptor 1 (AT1R) blocker losartan on vascular calcification in rat aortic artery and explore the underlying mechanisms. Methods SD rats were divided randomly into control group, vascular calcification model group and treatment group. Vascular calcification models were made by subcutaneous injection of warfarin plus vitamin K1 for two weeks. Rats in the treatment group were subcutaneously injected with losartan (10 mg/kg) at the end of the first week and consecutively for one week. We observed the morphological changes by HE staining and the calcium deposition by Alizarin red staining in the artery vascular wall. The mRNA expressions of bone morphogenetic protein 2 (BMP2) and Runt-related transcription factor 2 (RUNX2) were analyzed by reverse transcription PCR. The BMP2 and RUNX2 protein expressions were determined by Western blotting. The apoptosis of smooth muscle cells (SMCs) were detected by TUNEL. The AT1R expression was tested by fluorescent immunohistochemistry. Results The aortic vascular calcification was induced by warfarin and vitamin K1. Compared with the vascular calcification model group, the mRNA and protein expressions of BMP2 and RUNX2 were significantly downregulated in the aorta in the losartan treatment group. Furthermore, the apoptosis of SMCs and the AT1R expression obviously decreased. Conclusion AT1R blocker losartan inhibits the apoptosis of SMCs and reduces AT1R expression; it downregulates the BMP2 and RUNX2 expressions in the vascular calcification process.

  16. Design, synthesis and biological evaluation of novel ring-opened cromakalim analogues with relaxant effects on vascular and respiratory smooth muscles and as stimulators of elastin synthesis.

    Science.gov (United States)

    Bouhedja, Mourad; Peres, Basile; Fhayli, Wassim; Ghandour, Zeinab; Boumendjel, Ahcène; Faury, Gilles; Khelili, Smail

    2018-01-20

    Two new series of ring-opened analogues of cromakalim bearing sulfonylurea moieties (series A: with N-unmethylated sulfonylureas, series B: with N-methylated sulfonylureas) were synthesized and tested as relaxants of vascular and respiratory smooth muscles (rat aorta and trachea, respectively). Ex vivo biological evaluations indicated that the most active compounds, belonging to series B, displayed a marked vasorelaxant activity on endothelium-intact aortic rings and the trachea. A majority of series B compounds exhibited a higher vasorelaxant activity (EC 50  stronger relaxant effects on the trachea than the reference compound cromakalim (EC 50  = 124 μM), in particular compounds B4, B7 and B16 (EC 50   57 μM for all, and EC 50  > 200 μM for a majority of them), but some of them showed an interesting relaxing effect on trachea (i.e. A15 and A33, EC 50  = 30 μM). The most potent compounds of both series, i.e. A15, A33 and B16, tested on aortic rings in the presence of glibenclamide or 80 mM KCl, suggested that they acted as voltage-gated Ca 2+ channel blockers, like verapamil, instead of being ATP-potassium channel activators, as is cromakalim, the parent molecule. Further investigations on cultured vascular smooth muscle cells showed a strong stimulating effect on elastin synthesis, especially compound B16, which was more active at 20 μM than diazoxide, a reference ATP-sensitive potassium channel activator. Taken together, our results show that the N-methylation of the sulfonylurea moieties of ring-opened cromakalim analogues led to new compounds blocking calcium-gated channels, which had a major impact on the arterial and tracheal activities as well as selectivity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Benfotiamine counteracts smoking-induced vascular dysfunction in healthy smokers.

    Science.gov (United States)

    Stirban, Alin; Nandrean, Simona; Kirana, Stanley; Götting, Christian; Veresiu, Ioan Andrei; Tschoepe, Diethelm

    2012-01-01

    Background. Smoking induces endothelial dysfunction (ED) mainly by exacerbating oxidative stress (OS) and inflammation. Benfotiamine, a thiamine prodrug with high bioavailability, prevents nicotine-induced vascular dysfunction in rats. It remained unknown whether this effect also occurs in humans. Methods. Therefore, 20 healthy volunteers (mean age: 38 years) were investigated twice, 7-10 days apart in a randomized, cross-over, and investigator-blinded design. Vascular function was assessed by flow-mediated vasodilatation (FMD) of the brachial artery and by measurements of the soluble vascular cell adhesion molecule (sVCAM)-1. Investigations were performed after an overnight fast as well as 20 minutes after one cigarette smoking. On another day, the same procedure was applied following a 3-day oral therapy with benfotiamine (1050 mg/day). Ten patients were randomized to start with smoking alone, and ten started with benfotiamine. Results. Results are expressed as (mean ± SEM). Smoking acutely induced a decrease in FMD by 50% ((∗∗)P benfotiamine treatment to 25%(∗§) ((∗)P benfotiamine. The endothelium-independent vasodilatation remained unaltered between days. Conclusion. In healthy volunteers, smoking blunts vascular function mirrored by a decrease in FMD and an increase in sVCAM-1. Short-term treatment with benfotiamine significantly reduces these effects, showing protective vascular properties.

  18. Our vascular surgery experiences in Syrian civil war

    Directory of Open Access Journals (Sweden)

    İyad Fansa

    2014-12-01

    Full Text Available Objective: Due to the ongoing civil war in Syria, numerous vascular injured patients are admitted to our hospital with gunshot wounds. In this study, patients who admitted our hospital, diagnosed with vascular trauma due to gunshot were evaluated with the respect of injury site, additional injuries, surgical interventions and outcomes. Methods: The study included 58 patients wounded in Syrian war and admitted to our hospital between 01.01.2012 and 01.09.2014. Results= There were 5.1% (n=3 female and 94.9% (n=55 male patients. Age range is 5-75 years and the average of age was identified as 28.61. In 12.1% (n=7 of patients with extensive tissue defects of the muscle-nerve-bone injury has been identified, despite the vascular interventions in these patients, 8.6% (n=5 of patients, the limb has been amputated. Totally 15.5% (n=9 of 58 operated patients died. Two patients died because of major vascular injury with intra-abdominal organ injuries. In one patient; infection induced sepsis and multi organ failure was detected. Six patients were lost due to hypovolemic shock as a result of late arriving. Conclusion: In patients admitted with gunshot vascular injury arrival time, the presence of additional injuries and the location of injury affect mortality rates.

  19. Initial Clinical Experience Using the Amplatzer Vascular Plug

    International Nuclear Information System (INIS)

    Tuite, David J.; Kessel, David O.; Nicholson, Anthony A.; Patel, Jai V.; McPherson, Simon J.; Shaw, David R.

    2007-01-01

    Background and purpose. The Amplatzer Vascular Plug (AVP) is a self-expanding nitinol wire mesh vascular embolization device derived from the Amplatz septal occluder. We assessed the results of vascular embolization obtained using the AVP. Methods. A retrospective review was carried out of 23 consecutive cases of vascular embolization using the AVP in a variety of different clinical settings. The AVP was chosen to have a diameter approximately 30-50% greater than the target vessel. The device was delivered via an appropriately sized guide catheter and was released when satisfactorily positioned. Additional embolic agents were used in some cases. Results. All target vessels were successfully occluded with no device malpositioning or malfunction. In 14 (61%) patients the AVP was the sole embolic material. In the remaining patients additional agents were used, particularly in preoperative embolization of highly vascular renal tumors. The AVP does not cause instantaneous thrombosis and in high-flow situations thrombosis typically takes up to 15 min. Conclusion. The AVP is a safe, effective embolization device that provides a useful adjunct to the therapeutic armamentarium. It is particularly suited to the treatment of short high-flow vessels where coil migration and catheter dislodgment might occur. In the majority of cases no additional embolic agents are necessary but it may take up to 15 min for complete thrombosis to occur

  20. Channel Responses and Hydromodification in Southern California

    Science.gov (United States)

    Hawley, R. J.; Dust, D. W.; Bledsoe, B. P.

    2007-12-01

    Hydromodification (changes in watershed hydrologic characteristics, and the resulting hydraulics and channel forms due to urbanization) is ubiquitous in Southern California. In this region, the effects of hydromodification are driven and compounded by the arid/semiarid climate, high relief, erodible soils, high urbanization rates, and relatively low frequency of retention/detention. We conducted a preliminary survey of over 50 stream reaches along a gradient from least disturbed to fully urbanized. All stages of the Channel Evolution Model (CEM) of Schumm et al. (1984) were observed, from stable to degrading, widening, aggrading, and quasi-equilibrium channels. Several sites have CEM stages II through V in close proximity due to headcutting, hardpoints, and infrastructure. We also observed channels in undeveloped watersheds impacted by downstream urbanization via headcutting. A range of intervention measures was observed, with the frequent evolutionary endpoint as a concrete engineered flood control channel. We also observed multiple channel evolution sequences that deviate from the CEM for single-thread, incising channels. An alternative channel response, particularly on smaller urbanized streams is a stabilized, vegetation encroached low-flow channel with regular baseflow supplied by residential irrigation runoff. The limited cases of unimpacted streams that remain tend to be high gradient, high energy systems that are naturally proximate to the transition between braided and meandering form for a given sediment size.

  1. Vascular anatomy of the pig kidney glomerulus: a qualitative study of corrosion casts.

    Science.gov (United States)

    Moore, B J; Holmes, K R; Xu, L X

    1992-09-01

    Pig kidney glomerular vascular anatomy was studied by scanning electron microscopy of vascular corrosion casts. A generalized vascular architecture is presented to describe the pig kidney glomerulus based upon the observation of 3,800 vascular cast glomeruli. The relative simplicity of the pig glomerular vascular architecture has allowed the characterization of different vascular segments more completely than has been possible in other mammals. Based upon relationships to the afferent arteriole, a nomenclature and definition of primary, secondary, tertiary and anastomotic vessels is proposed for the distributing vessels comprising the glomerular tuft. The existence and formation of a large central hemispheric vessel deep within the confines of a glomerular hemisphere is micrographically documented. Micrographic evidence is presented supporting the formation of the single efferent arteriole by the merging of two central hemispheric vessels within the confines of the glomerular tuft. Failure of the merging of these two vessels may result in multiple efferent arterioles.

  2. Omni channel fashion shopping

    NARCIS (Netherlands)

    Kemperman, A.D.A.M.; van Delft, L.; Borgers, A.W.J.; Pantano, E.

    2015-01-01

    This chapter gives insight into consumers' online and offline fashion shopping behavior, consumers' omni-channel usage during the shopping process, and consumer fashion shopper segments. Based on a literature review, omni-channel shopping behavior during the shopping process was operationalized.

  3. Cardiac and vascular imaging with snapshot FLASH MR imaging

    International Nuclear Information System (INIS)

    Matthaei, D.; Haase, A.; Norris, D.; Leibfritz, D.; Henrich, D.; Duhmke, E.

    1989-01-01

    Acceleration of fast low-angle-shot (FLASH) MR imaging to about 200 msec measuring time on dedicated MR systems is called snapshot FLASH MR imaging. It snaps real-time series of MR images of the MR relaxation and of physiologic motions with nearly absent motion and susceptibility artifacts. Results in animals (4.7T) and human volunteers (2.0T) show plain vascular and cardiac snapshot FLASH MR images obtained as single shot, triggered reconstructed motion, or real-time films. The reduction of artifacts and the high resolution (triggered, three-dimensional moving heart images are possible) result in favorable applications in myocardial and great vascular disease

  4. Maintenance of vascular access patency in pediatrics

    International Nuclear Information System (INIS)

    Hoffer, F.A.; Wyly, J.B.; Fellows, K.E.; Harmon, W.; Levey, R.H.

    1986-01-01

    The patency of vascular access shunts and fistulae has been prolonged by a combined surgical and radiological approach that includes percutaneous transluminal angioplasty (PTA), surgical revision, thrombectomy, and thrombolysis. Over the last 3 years, 35 vascular accesses in 27 patients were found to have angiographic abnormality. PTA was performed 32 times of 19 accesses and 7 PTAs resulted in patent accesses by the end of the study. Surgical revision was performed 9 times on 8 accesses and 2 of the surgical revisions resulted in a patent access by the end of the study. Concerning Thomas femoral shunts, PTA prolonged the patency by 2.2 months and surgical revision by 3.8 months per procedure. Concerning arteriovenous (AV) fistulae, PTA prolonged the patency by 4.3 months and surgical revision by 3.5 months per procedure. A combination of procedures effectively doubles the duration of patency of Thomas femoral shunts and almost triples the duration of patency of AV fistulae in children. Forty-one percent of these accesses remain open 1 year following the initiation of these procedures. (orig.)

  5. Charged and Neutral Particles Channeling Phenomena Channeling 2008

    Science.gov (United States)

    Dabagov, Sultan B.; Palumbo, Luigi

    2010-04-01

    -- Probing channeling radiation influenced by ultrasound / W. Wagner ... [et al.] -- Radiation characteristics under electrons planar channeling and quasichanneling in complex crystals / L. Gevorgian -- Formation of relativistic positron atoms by axially channeled positrons and their decay on [symbol]-rays / A. Gevorkyan, A. R. Mkrtchyan and K. Oganesyan -- New features of diffracted channeling radiation from electrons in Si and LiF Crystals / K. B. Korotchenko, Yu. L. Pivovarov and T. A. Tukhfatullin -- Modulated particle beam in a crystal channel / A. Kostyuk ... [et al.] -- Computer simulations of resonant coherent excitation of heavy hydrogenlike ions under planar channeling / A. A. Babaev and Yu. L. Pivovarov -- Parametric x-ray and diffracted transition radiation of 4.5 GeV electrons in diamond / R. O. Avakian ... [et al.] -- Possible use of small accelerators in student laboratory for engineering education / I. Endo, M. Tanaka and T. Yoshimura.The Status of the SPARC Project / A. Cianchi -- Laser-plasma acceleration: first experimental results from the Plasmon-X Project / L. A. Gizzi ... [et al.] -- The powerful nanosecond duration electron beam effect on the crystalline tungsten target / Y. N. Adischev ... [et al.] -- "Shadowing" of the electromagnetic field of a relativistic electron / G. Naumenko ... [et al.] -- The acceleration of the charged particles in a low temperature acoustoplasma / A. S. Abrahamyan, A. R. Mkrtchyan and R. B. Kostanyan -- The experimental study of the surface current excitation by a relativistic electron electromagnetic field / G. A. Naumenko ... [et al.] -- Synchrotron radiation from a charge moving along helical orbit around a dielectric cylinder / A. A. Saharian and A. S. Kotanjyan -- Particle acceleration in a helical wave guide / X. Artru and C. Ray -- Effect of heavy ion charge fluctuations on Cherenkov radiation / V. S. Malyshevsky -- Hard photons powerful radiation of electron bunch interacting with plasma beat waves / A. Shamamian

  6. Channel electron multipliers

    International Nuclear Information System (INIS)

    Seidman, A.; Avrahami, Z.; Sheinfux, B.; Grinberg, J.

    1976-01-01

    A channel electron multiplier is described having a tubular wall coated with a secondary-electron emitting material and including an electric field for accelerating the electrons, the electric field comprising a plurality of low-resistive conductive rings each alternating with a high-resistive insulating ring. The thickness of the low-resistive rings is many times larger than that of the high-resistive rings, being in the order of tens of microns for the low-resistive rings and at least one order of magnitude lower for the high-resistive rings; and the diameter of the channel tubular walls is also many times larger than the thickness of the high-resistive rings. Both single-channel and multiple-channel electron multipliers are described. A very important advantage, particularly in making multiple-channel multipliers, is the simplicity of the procedure that may be used in constructing such multipliers. Other operational advantages are described

  7. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...... drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate...... that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K(+) channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure...

  8. Cl- channels in apoptosis

    DEFF Research Database (Denmark)

    Wanitchakool, Podchanart; Ousingsawat, Jiraporn; Sirianant, Lalida

    2016-01-01

    A remarkable feature of apoptosis is the initial massive cell shrinkage, which requires opening of ion channels to allow release of K(+), Cl(-), and organic osmolytes to drive osmotic water movement and cell shrinkage. This article focuses on the role of the Cl(-) channels LRRC8, TMEM16/anoctamin......, and cystic fibrosis transmembrane conductance regulator (CFTR) in cellular apoptosis. LRRC8A-E has been identified as a volume-regulated anion channel expressed in many cell types. It was shown to be required for regulatory and apoptotic volume decrease (RVD, AVD) in cultured cell lines. Its presence also......(-) channels or as regulators of other apoptotic Cl(-) channels, such as LRRC8. CFTR has been known for its proapoptotic effects for some time, and this effect may be based on glutathione release from the cell and increase in cytosolic reactive oxygen species (ROS). Although we find that CFTR is activated...

  9. CHANNEL ESTIMATION TECHNIQUE

    DEFF Research Database (Denmark)

    2015-01-01

    A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over the communicat......A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over...... the communication channel. The method further includes determining a sequence of second coefficient estimates of the communication channel based on a decomposition of the first coefficient estimates in a dictionary matrix and a sparse vector of the second coefficient estimates, the dictionary matrix including...... filter characteristics of at least one known transceiver filter arranged in the communication channel....

  10. Current concepts in the classification, diagnosis and treatment of vascular anomalies

    International Nuclear Information System (INIS)

    Ernemann, Ulrike; Kramer, Ulrich; Miller, Stephan; Bisdas, Sotirios; Rebmann, Hans; Breuninger, Helmut; Zwick, Christine; Hoffmann, Juergen

    2010-01-01

    Patients with extended vascular anomalies may suffer from significant aesthetic and functional impairment and represent a challenge to therapeutic planning, which is best met by an interdisciplinary concept. In agreement with the International Society for the Study of Vascular Anomalies (ISSVA), vascular lesions are classified into haemangiomas as proliferating endothelial tumours on the one hand and congenital vascular malformations on the other. According to the preponderant vascular channels and hemodynamic characteristics, malformations are subdivided into low flow (venous, lymphatic and capillary) lesions and high-flow malformations. Diagnostic imaging should be targeted at the specific structural and functional informations required for treatment planning. The imaging modality of choice to provide these informations is magnetic resonance imaging (MRI) supplemented by magnetic resonance angiography (MRA) with high spatial and temporal resolution. Treatment indications for haemangiomas depend on the proliferative behaviour of the lesion and comprise β-blockers in order to induce involution as well as cryotherapy, laser and open surgery. Interventional radiological procedures have evolved as an essential element in an interdisciplinary treatment plan for vascular malformations and include percutaneous sclerotherapy with ethanol and OK-432 for venous and lymphatic malformations and transarterial embolization for high-flow lesions.

  11. Current concepts in the classification, diagnosis and treatment of vascular anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Ernemann, Ulrike, E-mail: ulrike.ernemann@med.uni-tuebingen.d [Department of Diagnostic and Interventional Neuroradiology, Radiological Clinic, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Kramer, Ulrich; Miller, Stephan [Department of Diagnostic and Interventional Radiology, Radiological Clinic, University Hospital Tuebingen (Germany); Bisdas, Sotirios [Department of Diagnostic and Interventional Neuroradiology, Radiological Clinic, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Rebmann, Hans [Department of Paediatrics, Children' s Hospital, University Hospital Tuebingen (Germany); Breuninger, Helmut [Department of Dermatology, University Hospital Tuebingen (Germany); Zwick, Christine [Department of Hand, Plastic, Reconstructive and Burns Surgery, BG Trauma Clinic Tuebingen, University Hospital Tuebingen (Germany); Hoffmann, Juergen [Department of Oral and Maxillofacial Surgery, University Hospital Tuebingen (Germany)

    2010-07-15

    Patients with extended vascular anomalies may suffer from significant aesthetic and functional impairment and represent a challenge to therapeutic planning, which is best met by an interdisciplinary concept. In agreement with the International Society for the Study of Vascular Anomalies (ISSVA), vascular lesions are classified into haemangiomas as proliferating endothelial tumours on the one hand and congenital vascular malformations on the other. According to the preponderant vascular channels and hemodynamic characteristics, malformations are subdivided into low flow (venous, lymphatic and capillary) lesions and high-flow malformations. Diagnostic imaging should be targeted at the specific structural and functional informations required for treatment planning. The imaging modality of choice to provide these informations is magnetic resonance imaging (MRI) supplemented by magnetic resonance angiography (MRA) with high spatial and temporal resolution. Treatment indications for haemangiomas depend on the proliferative behaviour of the lesion and comprise {beta}-blockers in order to induce involution as well as cryotherapy, laser and open surgery. Interventional radiological procedures have evolved as an essential element in an interdisciplinary treatment plan for vascular malformations and include percutaneous sclerotherapy with ethanol and OK-432 for venous and lymphatic malformations and transarterial embolization for high-flow lesions.

  12. MFAP4 Promotes Vascular Smooth Muscle Migration, Proliferation and Accelerates Neointima Formation

    DEFF Research Database (Denmark)

    Schlosser, Anders; Pilecki, Bartosz; Hemstra, Line E.

    2016-01-01

    in the vascular wall. The role of MFAP4 in vascular biology is unknown. We aimed to test the hypothesis that MFAP4 would enhance integrin-dependent VSMC activation. APPROACH AND RESULTS: We produced Mfap4-deficient (Mfap4(-/-)) mice and performed carotid artery ligation to explore the role of MFAP4 in vascular...... kinase and downstream kinases. In addition, we showed that MFAP4 promotes monocyte chemotaxis in integrin αVβ3-dependent manner. CONCLUSIONS: MFAP4 regulates integrin αVβ3-induced VSMC proliferation and migration, as well as monocyte chemotaxis, and accelerates neointimal hyperplasia after vascular...

  13. Pulsatile atheroprone shear stress affects the expression of transient receptor potential channels in human endothelial cells

    DEFF Research Database (Denmark)

    Thilo, Florian; Vorderwülbecke, Bernd J; Marki, Alex

    2012-01-01

    in comparison with endothelial cells grown under static conditions. There was a significant association between the expression of TRPC6 and tumor necrosis factor-α mRNA in human vascular tissue. No-flow and atheroprone flow conditions are equally characterized by an increase in the expression of tumor necrosis......The goal of the study was to assess whether pulsatile atheroprone shear stress modulates the expression of transient receptor potential (TRP) channels, TRPC3, TRPC6, TRPM7, and TRPV1 mRNA, in human umbilical vascular endothelial cells. Exposure of cultured vascular endothelial cells to defined...

  14. Coupling of laser energy into plasma channels

    International Nuclear Information System (INIS)

    Dimitrov, D. A.; Giacone, R. E.; Bruhwiler, D. L.; Busby, R.; Cary, J. R.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2007-01-01

    Diffractive spreading of a laser pulse imposes severe limitations on the acceleration length and maximum electron energy in the laser wake field accelerator (LWFA). Optical guiding of a laser pulse via plasma channels can extend the laser-plasma interaction distance over many Rayleigh lengths. Energy efficient coupling of laser pulses into and through plasma channels is very important for optimal LWFA performance. Results from simulation parameter studies on channel guiding using the particle-in-cell (PIC) code VORPAL [C. Nieter and J. R. Cary, J. Comput. Phys. 196, 448 (2004)] are presented and discussed. The effects that density ramp length and the position of the laser pulse focus have on coupling into channels are considered. Moreover, the effect of laser energy leakage out of the channel domain and the effects of tunneling ionization of a neutral gas on the guided laser pulse are also investigated. Power spectral diagnostics were developed and used to separate pump depletion from energy leakage. The results of these simulations show that increasing the density ramp length decreases the efficiency of coupling a laser pulse to a channel and increases the energy loss when the pulse is vacuum focused at the channel entrance. Then, large spot size oscillations result in increased energy leakage. To further analyze the coupling, a differential equation is derived for the laser spot size evolution in the plasma density ramp and channel profiles are simulated. From the numerical solution of this equation, the optimal spot size and location for coupling into a plasma channel with a density ramp are determined. This result is confirmed by the PIC simulations. They show that specifying a vacuum focus location of the pulse in front of the top of the density ramp leads to an actual focus at the top of the ramp due to plasma focusing, resulting in reduced spot size oscillations. In this case, the leakage is significantly reduced and is negligibly affected by ramp length

  15. Quality assurance of lower limb venous duplex scans performed by vascular surgeons.

    Science.gov (United States)

    Kordowicz, A; Ferguson, G; Salaman, R; Onwudike, M

    2015-02-01

    Duplex scanning is the gold standard for investigating venous reflux; increasingly surgeons perform these scans themselves. There has been no data published analysing the accuracy of Duplex scans performed by vascular surgeons. We aimed to evaluate an objective method of comparing the results of lower limb Duplex scans performed by one consultant vascular surgeon with those performed by a vascular technologist. We assessed 100 legs with symptomatic varicose veins. Each patient underwent two lower limb venous Duplex scans; one performed by a consultant vascular surgeon and one by a vascular technologist. Scan results were randomised and sent to two consultant vascular surgeons blinded to the identity and experience of the sonographer. They were asked to recommend treatment. A k score was calculated in each case to assess the level of agreement between the scans performed by the consultant and the technologist. Eighty-one patients were studied (53 females). The kappa score for assessor 1 was 0.60 (95%CI:0.44-0.75) and for assessor 2 was 0.62 (95%CI:0.48-0.75). k scores >0.60 represent a substantial strength of agreement. Duplex scans performed by this surgeon were comparable to those performed by a vascular technologist. It is possible to quality-assure duplex performed by vascular surgeons without directly observing the scanning process or reviewing digitally recorded images. We propose standardisation of training, assessment and quality assurance for vascular surgeons wishing to perform ultrasound scans.

  16. Reliable quantum communication over a quantum relay channel

    Energy Technology Data Exchange (ETDEWEB)

    Gyongyosi, Laszlo, E-mail: gyongyosi@hit.bme.hu [Quantum Technologies Laboratory, Department of Telecommunications, Budapest University of Technology and Economics, 2 Magyar tudosok krt, Budapest, H-1117, Hungary and Information Systems Research Group, Mathematics and Natural Sciences, Hungarian Ac (Hungary); Imre, Sandor [Quantum Technologies Laboratory, Department of Telecommunications, Budapest University of Technology and Economics, 2 Magyar tudosok krt, Budapest, H-1117 (Hungary)

    2014-12-04

    We show that reliable quantum communication over an unreliable quantum relay channels is possible. The coding scheme combines the results on the superadditivity of quantum channels and the efficient quantum coding approaches.

  17. Radiological findings and interventions for iatrogenic vascular injuries

    International Nuclear Information System (INIS)

    Lee, Kyoung Ho; Chung, Jin Wook; Kim, Tae Kyoung; Han, Sang Wook; Lee, Jong Seog; Park, Jae Hyung; Kim, Jong Hyo; Han, Man Chung

    1998-01-01

    The purpose of this study is to evaluate the radiological findings and effectiveness of radiological interventions in patients with iatrogenic vascular injuries. We analyzed 50 patients with iatrogenic vascular injuries treated with radiological intervention. The causes of injuries were surgery (n=20), cardiovascular intervention (n=15), non-cardiovascular radiological intervention (n=14), and endoscopic intervention (n=1). The injury had resulted in hemorrhage in 35 cases. The iliac and/or femoral, hepatic, and renal vessels were commonly injured. Angiography, ultrasonography with Doppler examination, CT, and CT angiography were performed to diagnose vascular injuries and guide the radiological intervention. The mean follow-up period was 23 months and in 16 cases was more than one year. the major radiological findings were extravasation, pseudoaneurysm, arteriovenous shunt, or vascular obstruction. To control these lesions, radiological interventions such as embolization (n=36), local urokinase administration, stent insertion, foreign body removal, ultrasonography-guided compression, or stent-graft insertion were performed. The clinical problems were immediately controlled by the single trials of radiological interventions and did not recur in 40 cases (80%). Radiological examinations and interventions are useful in cases with iatrogenic vascular injuries. (author). 14 refs., 4 figs

  18. Self-Replenishing Vascularized Fouling-Release Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Howell, C; Vu, TL; Lin, JJ; Kolle, S; Juthani, N; Watson, E; Weaver, JC; Alvarenga, J; Aizenberg, J

    2014-08-13

    Inspired by the long-term effectiveness of living antifouling materials, we have developed a method for the self-replenishment of synthetic biofouling-release surfaces. These surfaces are created by either molding or directly embedding 3D vascular systems into polydimethylsiloxane (PDMS) and filling them with a silicone oil to generate a nontoxic oil-infused material. When replenished with silicone oil from an outside source, these materials are capable of self-lubrication and continuous renewal of the interfacial fouling-release layer. Under accelerated lubricant loss conditions, fully infused vascularized samples retained significantly more lubricant than equivalent nonvascularized controls. Tests of lubricant-infused PDMS in static cultures of the infectious bacteria Staphylococcus aureus and Escherichia coli as well as the green microalgae Botryococcus braunii, Chlamydomonas reinhardtii, Dunaliella sauna, and Nannochloropsis oculata showed a significant reduction in biofilm adhesion compared to PDMS and glass controls containing no lubricant. Further experiments on vascularized versus nonvascularized samples that had been subjected to accelerated lubricant evaporation conditions for up to 48 h showed significantly less biofilm adherence on the vascularized surfaces. These results demonstrate the ability of an embedded lubricant-filled vascular network to improve the longevity of fouling-release surfaces.

  19. Towards the therapeutic use of vascular smooth muscle progenitor cells.

    Science.gov (United States)

    Merkulova-Rainon, Tatyana; Broquères-You, Dong; Kubis, Nathalie; Silvestre, Jean-Sébastien; Lévy, Bernard I

    2012-07-15

    Recent advances in the development of alternative proangiogenic and revascularization processes, including recombinant protein delivery, gene therapy, and cell therapy, hold the promise of greater efficacy in the management of cardiovascular disease in the coming years. In particular, vascular progenitor cell-based strategies have emerged as an efficient treatment approach to promote vessel formation and repair and to improve tissue perfusion. During the past decade, considerable progress has been achieved in understanding therapeutic properties of endothelial progenitor cells, while the therapeutic potential of vascular smooth muscle progenitor cells (SMPC) has only recently been explored; the number of the circulating SMPC being correlated with cardiovascular health. Several endogenous SMPC populations with varying phenotypes have been identified and characterized in the peripheral blood, bone marrow, and vascular wall. While the phenotypic entity of vascular SMPC is not fully defined and remains an evolving area of research, SMPC are increasingly recognized to play a special role in cardiovascular biology. In this review, we describe the current approaches used to define vascular SMPC. We further summarize the data on phenotype and functional properties of SMPC from various sources in adults. Finally, we discuss the role of SMPC in cardiovascular disease, including the contribution of SMPC to intimal proliferation, angiogenesis, and atherosclerotic plaque instability as well as the benefits resulting from the therapeutic use of SMPC.

  20. Hopping control channel MAC protocol for opportunistic spectrum access networks

    Institute of Scientific and Technical Information of China (English)

    FU Jing-tuan; JI Hong; MAO Xu

    2010-01-01

    Opportunistic spectrum access (OSA) is considered as a promising approach to mitigate spectrum scarcity by allowing unlicensed users to exploit spectrum opportunities in licensed frequency bands. Derived from the existing channel-hopping multiple access (CHMA) protocol,we introduce a hopping control channel medium access control (MAC) protocol in the context of OSA networks. In our proposed protocol,all nodes in the network follow a common channel-hopping sequence; every frequency channel can be used as control channel and data channel. Considering primary users' occupancy of the channel,we use a primary user (PU) detection model to calculate the channel availability for unlicensed users' access. Then,a discrete Markov chain analytical model is applied to describe the channel states and deduce the system throughput. Through simulation,we present numerical results to demonstrate the throughput performance of our protocol and thus validate our work.

  1. Vascular dementia: Facts and controversies

    Directory of Open Access Journals (Sweden)

    Pavlović Aleksandra

    2013-01-01

    Full Text Available Vascular dementia (VaD is the second most frequent dementia after Alzheimer’s disease, and is diagnosed during lifetime in 20% of demented patients. Five­year survival rate in VaD is 39%, while it is estimated to be 75% in healthy persons of the same age. It is therefore important to make correct diagnosis of VaD early in the course of the disease. Risk factors for VaD are identical to stroke risk factors, and there are significant possibilities for the prevention of vascular cognitive decline. Cognitive decline develops acutely or step­by­step within three months after stroke, but more gradual progression of intellectual decline is also possible. Neurological examination can reveal pyramidal and extrapyramidal signs, pseudobulbar palsy, gait disturbance and urinary incontinence. Neuropsychological profile comprises the loss of cognitive set shifting, decline in word fluency, verbal learning difficulties, perseverations, difficulties in complex figure copying, and in patients with cortically located lesions also problems with speech and praxia. The basis of the diagnosis is, besides history, neurological examination and neuropsychological assessment, computed tomography and/ or magnetic resonance brain imaging. Vascular risk factors control is the most important measure in VaD prevention. Modern guidelines for the treatment of cognitive decline in VaD emphasize that donepezil can be useful in the improvement of cognitive status at the level of Class IIa recommendation at the level of evidence A, while memantine may be useful in patients with mixed VaD and Alzheimer’s disease dementia. [Projekat Ministarstva nauke Republike Srbije, br. 175022 i br. 175033

  2. Late vascular effects in irradiated mice brain

    International Nuclear Information System (INIS)

    Yoshii, Yoshihiko; Maki, Yutaka; Phillips, T.L.

    1982-01-01

    The whole brains of mice were irradiated with 250 kVp X-ray at 120 rad min -1 (1.6 mm Cu HVL, TSD 50 cm) and a histological study was done. The dose range of X-irradiation was from 1300 to 2500 rads. i.e., 1300, 1500, 1750, 2000, and 2500 rads. In the microscopic examination, the mice were killed at the regular postirradiation intervals of between 15 and 20, 31 and 40, 41 and 50, 51 and 60, 61 and 70, 71 and 80, 81 and 90, 139 and 177 weeks. A histological examination was performed by a morphometric estimation of vascular lesion in which the degree of the damage to the arterial system was scored through whole serial brain sections. Necrosis (encephalomalacia), atrophy, cell infiltration, and telangiectatic vascular change of the brain, caused as a result of the fibrinoid necrosis of the large artery were observed. Incidence of the fibrinoid necrosis increased dose dependently between 41 and 87 weeks after irradiation. Mean score of fibrinoid necrosis increased dose dependently approximately 60 weeks after irradiation. It is suggested that scores of large vessel damage do relate to dose at 41 - 87 weeks and can be used to quantify the vessel injury and a fibrinoid necrosis of the large vessels may relate to the incidence of radionecrosis. (author)

  3. Non-vascular surgical mediastinum

    International Nuclear Information System (INIS)

    Schiavon, S.; Trenaghi, P.; Nardini, S.; Pagan, V.

    1989-01-01

    A review was made of the chest X-ray features of 120 patients who underwent surgical treatment for mediastinal non-vascular pathologies over the past 12 years in the Mestre Hospital. A method of analysis is proposed which takes into account not only the differences between the immediate post-operative period and the follow-up, but also the anatomotopographic partition and the surgical practice. Normal and pathological patterns for both of the above periods are described. The ''dimness'' of the arial tracheogram is emphasized as a usefull and early sign of mediastinal recurrence

  4. Vascular comorbidities in multiple sclerosis

    DEFF Research Database (Denmark)

    Thormann, Anja; Magyari, Melinda; Koch-Henriksen, Nils

    2016-01-01

    To investigate the occurrence of vascular comorbidities before and after the clinical onset of multiple sclerosis. In this combined case-control and cohort study, all Danish born citizens with onset of multiple sclerosis 1980-2005 were identified from the Danish Multiple Sclerosis Registry...... and randomly matched with controls regarding year of birth, gender, and municipality on January 1st in the year of multiple sclerosis (MS) onset (index date). Individual-level information on comorbidities was obtained from several independent nationwide registries and linked to the study population by unique...

  5. Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

    Directory of Open Access Journals (Sweden)

    Cheng-Wei Kuo

    2017-01-01

    Full Text Available Recurrent flood events induced by typhoons are powerful agents to modify channel morphology in Taiwan’s rivers. Frequent channel migrations reflect highly sensitive valley floors and increase the risk to infrastructure and residents along rivers. Therefore, monitoring channel planforms is essential for analyzing channel stability as well as improving river management. This study analyzed annual channel changes along two sediment-rich rivers, the Zhuoshui River and the Gaoping River, from 2008 to 2015 based on satellite images of FORMOSAT-2. Channel areas were digitized from mid-catchment to river mouth (~90 km. Channel stability for reaches was assessed through analyzing the changes of river indices including braid index, active channel width, and channel activity. In general, the valley width plays a key role in braided degree, active channel width, and channel activity. These indices increase as the valley width expands whereas the braid index decreases slightly close to the river mouth due to the change of river types. This downstream pattern in the Zhuoshui River was interrupted by hydraulic construction which resulted in limited changes downstream from the weir, due to the lack of water and sediment supply. A 200-year flood, Typhoon Morakot in 2009, induced significant changes in the two rivers. The highly active landscape in Taiwan results in very sensitive channels compared to other regions. An integrated Sensitivity Index was proposed for identifying unstable reaches, which could be a useful reference for river authorities when making priorities in river regulation strategy. This study shows that satellite image monitoring coupled with river indices analysis could be an effective tool to evaluate spatial and temporal changes in channel stability in highly dynamic river systems.

  6. Evaluation of cell viability and functionality in vessel-like bioprintable cell-laden tubular channels.

    Science.gov (United States)

    Yu, Yin; Zhang, Yahui; Martin, James A; Ozbolat, Ibrahim T

    2013-09-01

    Organ printing is a novel concept recently introduced in developing artificial three-dimensional organs to bridge the gap between transplantation needs and organ shortage. One of the major challenges is inclusion of blood-vessellike channels between layers to support cell viability, postprinting functionality in terms of nutrient transport, and waste removal. In this research, we developed a novel and effective method to print tubular channels encapsulating cells in alginate to mimic the natural vascular system. An experimental investigation into the influence on cartilage progenitor cell (CPCs) survival, and the function of printing parameters during and after the printing process were presented. CPC functionality was evaluated by checking tissue-specific genetic marker expression and extracellular matrix production. Our results demonstrated the capability of direct fabrication of cell-laden tubular channels by our newly designed coaxial nozzle assembly and revealed that the bioprinting process could induce quantifiable cell death due to changes in dispensing pressure, coaxial nozzle geometry, and biomaterial concentration. Cells were able to recover during incubation, as well as to undergo differentiation with high-level cartilage-associated gene expression. These findings may not only help optimize our system but also can be applied to biomanufacturing of 3D functional cellular tissue engineering constructs for various organ systems.

  7. Coherifying quantum channels

    Science.gov (United States)

    Korzekwa, Kamil; Czachórski, Stanisław; Puchała, Zbigniew; Życzkowski, Karol

    2018-04-01

    Is it always possible to explain random stochastic transitions between states of a finite-dimensional system as arising from the deterministic quantum evolution of the system? If not, then what is the minimal amount of randomness required by quantum theory to explain a given stochastic process? Here, we address this problem by studying possible coherifications of a quantum channel Φ, i.e., we look for channels {{{Φ }}}{ \\mathcal C } that induce the same classical transitions T, but are ‘more coherent’. To quantify the coherence of a channel Φ we measure the coherence of the corresponding Jamiołkowski state J Φ. We show that the classical transition matrix T can be coherified to reversible unitary dynamics if and only if T is unistochastic. Otherwise the Jamiołkowski state {J}{{Φ }}{ \\mathcal C } of the optimally coherified channel is mixed, and the dynamics must necessarily be irreversible. To assess the extent to which an optimal process {{{Φ }}}{ \\mathcal C } is indeterministic we find explicit bounds on the entropy and purity of {J}{{Φ }}{ \\mathcal C }, and relate the latter to the unitarity of {{{Φ }}}{ \\mathcal C }. We also find optimal coherifications for several classes of channels, including all one-qubit channels. Finally, we provide a non-optimal coherification procedure that works for an arbitrary channel Φ and reduces its rank (the minimal number of required Kraus operators) from {d}2 to d.

  8. Changes in river channel pattern as a result of the construction, operation and decommissioning of watermills – the case of the middle reach of the River Liswarta near Krzepice, Poland

    OpenAIRE

    Fajer Maria

    2018-01-01

    Changes in river channel pattern in the middle reach of the River Liswarta and in the lower reaches of its tributaries near Krzepice were analysed, and were related to the construction, operation and decommissioning of watermills. For this purpose, old maps which covered the period from the beginning of the 18th century until the 20th century were used alongside written historical sources. Maps from the first half of the 19th century provided valuable source material. Traces of old mill water...

  9. Reconfigurable virtual electrowetting channels.

    Science.gov (United States)

    Banerjee, Ananda; Kreit, Eric; Liu, Yuguang; Heikenfeld, Jason; Papautsky, Ian

    2012-02-21

    Lab-on-a-chip systems rely on several microfluidic paradigms. The first uses a fixed layout of continuous microfluidic channels. Such lab-on-a-chip systems are almost always application specific and far from a true "laboratory." The second involves electrowetting droplet movement (digital microfluidics), and allows two-dimensional computer control of fluidic transport and mixing. The merging of the two paradigms in the form of programmable electrowetting channels takes advantage of both the "continuous" functionality of rigid channels based on which a large number of applications have been developed to date and the "programmable" functionality of digital microfluidics that permits electrical control of on-chip functions. In this work, we demonstrate for the first time programmable formation of virtual microfluidic channels and their continuous operation with pressure driven flows using an electrowetting platform. Experimental, theoretical, and numerical analyses of virtual channel formation with biologically relevant electrolyte solutions and electrically-programmable reconfiguration are presented. We demonstrate that the "wall-less" virtual channels can be formed reliably and rapidly, with propagation rates of 3.5-3.8 mm s(-1). Pressure driven transport in these virtual channels at flow rates up to 100 μL min(-1) is achievable without distortion of the channel shape. We further demonstrate that these virtual channels can be switched on-demand between multiple inputs and outputs. Ultimately, we envision a platform that would provide rapid prototyping of microfluidic concepts and would be capable of a vast library of functions and benefitting applications from clinical diagnostics in resource-limited environments to rapid system prototyping to high throughput pharmaceutical applications.

  10. Evaluation and percutaneous management of atherosclerotic peripheral vascular disease

    International Nuclear Information System (INIS)

    Widlus, D.M.; Osterman, F.A. Jr.

    1989-01-01

    Atherosclerotic peripheral vascular disease (PVD) of the lower extremities deprives a person of the ability to exercise to their satisfaction, later of the ability to perform the activities of their daily life, and finally of their legs themselves. Peripheral vascular disease has long been managed by the vascular surgeon utilizing endarterectomy and peripheral arterial bypass. Patient acceptance of nonsurgical, percutaneous procedures such as percutaneous transluminal balloon angioplasty (PTA) is high. Increased utilization of these procedures has led to improved techniques and adjuncts to therapy, as well as more critical review of long-term results. This article will review the evaluation and nonoperative management of PVD, with an emphasis on the newer modalities of management presently being investigated

  11. Defibrotide modulates prostaglandin production in the rat mesenteric vascular bed.

    Science.gov (United States)

    Peredo, H A

    2002-10-01

    Defibrotide 1 microM, a polydeoxyribonucleotide extracted from mammalian organs, reduced the contractile responses to noradrenaline (NA) in the rat isolated and perfused mesenteric vascular bed, in intact as well as in de-endothelialized preparations. Defibrotide was without effect on the acetylcholine-induced relaxations of U-46619-precontracted mesenteric vascular beds. Moreover, defibrotide increased 6-keto prostaglandin (PG) F(2alpha) (stable metabolite of prostacyclin) release sixfold in the presence, but not in the absence of the endothelium, with no modification on the release of other prostanoids. Defibrotide also inhibited the NA-induced increase in PGF(2alpha) release, in both intact and de-endothelialized mesenteric vascular beds. In conclusion, the present results show that defibrotide modulates PG production in the mesenteric bed and that the observed inhibition of the contractile responses should be due to the impairment of the NA-induced increase in PGF(2alpha) release.

  12. Evaluation channel performance in multichannel environments

    NARCIS (Netherlands)

    Gensler, S.; Dekimpe, M.; Skiera, B.

    2007-01-01

    Evaluating channel performance is crucial for actively managing multiple sales channels, and requires understanding the customers' channel preferences. Two key components of channel performance are (i) the existing customers' intrinsic loyalty to a particular channel and (ii) the channel's ability