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Sample records for hemodynamic stress region

  1. A Shape Memory Polymer Dialysis Needle Adapter for the Reduction of Hemodynamic Stress within Arteriovenous Grafts

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    Ortega, J M; Small, W; Wilson, T S; Benett, W; Loge, J; Maitland, D J

    2006-08-16

    A deployable, shape memory polymer adapter is investigated for reducing the hemodynamic stress caused by a dialysis needle flow within an arteriovenous graft. Computational fluid dynamics simulations of dialysis sessions with and without the adapter demonstrate that the adapter provides a significant decrease in the wall shear stress. In vitro flow visualization measurements are made within a graft model following delivery and actuation of a prototype shape memory polymer adapter. Vascular access complications resulting from arteriovenous (AV) graft failures account for over $1 billion per year in the health care costs of dialysis patients in the U.S.[1] The primary mode of failure of arteriovenous fistulas (AVF's) and polytetrafluoroethylene (PTFE) grafts is the development of intimal hyperplasia (IH) and the subsequent formation of stenotic lesions, resulting in a graft flow decline. The hemodynamic stresses arising within AVF's and PTFE grafts play an important role in the pathogenesis of IH. Studies have shown that vascular damage can occur in regions where there is flow separation, oscillation, or extreme values of wall shear stress (WSS).[2] Nevaril et al.[3] show that exposure of red blood cells to WSS's on the order of 1500 dynes/cm2 can result in hemolysis. Hemodynamic stress from dialysis needle flow has recently been investigated for the role it plays in graft failure. Using laser Doppler velocimetry measurements, Unnikrishnan et al.[4] show that turbulence intensities are 5-6 times greater in the AV flow when the needle flow is present and that increased levels of turbulence exist for approximately 7-8cm downstream of the needle. Since the AVF or PTFE graft is exposed to these high levels of hemodynamic stress several hours each week during dialysis sessions, it is quite possible that needle flow is an important contributor to vascular access occlusion.[4] We present a method for reducing the hemodynamic stress in an AV graft by tailoring

  2. Central and regional hemodynamics in prolonged space flights

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    Gazenko, O. G.; Shulzhenko, E. B.; Turchaninova, V. F.; Egorov, A. D.

    This paper presents the results of measuring central and regional (head, forearm, calf) hemodynamics at rest and during provocative tests by the method of tetrapolar rheography in the course of Salyut-6-Soyuz and Salyut-7-Soyuz missions. The measurements were carried out during short-term (19 man-flights of 7 days in duration) and long-term (21 man-flights of 65-237 days in duration) manned missions. At rest, stroke volume (SV) and cardiac output (CO) as well as heart rate (HR) decreased insignificantly (in short-term flights) or remained essentially unchanged (in long-term flights). In prolonged flights CO increased significantly in response to exercise tests due to an increase in HR and the lack of changes in SV. After exercise tests SV and CO decreased as compared to the preflight level. During lower body negative pressure (LBNP) tests HR and CO were slightly higher than preflight. Changes in regional hemodynamics included a distinct decrease of pulse blood filling (PBF) of the calf, a reduction of the tone of large vessels of the calf and small vessels of the forearm. Head examination (in the region of the internal carotid artery) showed a decrease of PBF of the left hemisphere (during flight months 2-8) and a distinct decline of the tone of small vessels, mainly, in the right hemisphere. During LBNP tests the tone of pre- and postcapillary vessels of the brain returned to normal while PBF of the right and left hemisphere vessels declined. It has been shown that regional circulation variations depend on the area examined and are induced by a rearrangement of total hemodynamics of the human body in microgravity. This paper reviews the data concerning changes in central and regional circulation of men in space flights of different duration.

  3. Endovascular Treatment of Thoracic Aortic Dissection: Hemodynamic Shear Stress Study

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    Tang, Yik Sau; Lai, Siu Kai; Cheng, Stephen Wing Keung; Chow, Kwok Wing

    2012-11-01

    Thoracic Aortic Dissection (TAD), a life threatening cardiovascular disease, occurs when blood intrudes into the layers of the aortic wall, creating a new artificial channel (the false lumen) beside the original true lumen. The weakened false lumen wall may expand, enhancing the risk of rupture and resulting in high mortality. Endovascular treatment involves the deployment of a stent graft into the aorta, thus blocking blood from entering the false lumen. Due to the irregular geometry of the aorta, the stent graft, however, may fail to conform to the vessel curvature, and would create a ``bird-beak'' configuration, a wedge-shaped domain between the graft and the vessel wall. Computational fluid dynamics analysis is employed to study the hemodynamics of this pathological condition. With the `beaking' configuration, the local hemodynamic shear stress will drop below the threshold of safety reported earlier in the literature. The oscillating behavior of the shear stress might lead to local inflammation, atherosclerosis and other undesirable consequences. Supported by the Innovation and Technology Fund of the Hong Kong Government.

  4. Gender affects sympathetic and hemodynamic response to postural stress

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    Shoemaker, J. K.; Hogeman, C. S.; Khan, M.; Kimmerly, D. S.; Sinoway, L. I.

    2001-01-01

    We tested the hypothesis that differences in sympathetic reflex responses to head-up tilt (HUT) between males (n = 9) and females (n = 8) were associated with decrements in postural vasomotor responses in women. Muscle sympathetic nerve activity (MSNA; microneurography), heart rate, stroke volume (SV; Doppler), and blood pressure (Finapres) were measured during a progressive HUT protocol (5 min at each of supine, 20 degrees, 40 degrees, and 60 degrees ). MSNA and hemodynamic responses were also measured during the cold pressor test (CPT) to examine nonbaroreflex neurovascular control. SV was normalized to body surface area (SV(i)) to calculate the index of cardiac output (Q(i)), and total peripheral resistance (TPR). During HUT, heart rate increased more in females versus males (P gender-specific autonomic responses to cardiovascular stress. The different MSNA response to postural stress between genders may contribute importantly to decrements in blood pressure control during HUT in females.

  5. Effect of arotinolol on hemodynamics and plasma atrial natriuretic peptide at rest and during stress in spontaneously hypertensive rats.

    Science.gov (United States)

    Yamamoto, J; Matsubara, H; Nakai, M

    1989-01-01

    We investigated the effects of chronic treatment with arotinolol, a beta-blocker with weak alpha-blocking potency, on hemodynamics and plasma levels of catecholamines and atrial natriuretic peptide (ANP) at rest and during stress in spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. At rest, arotinolol treatment decreased mean arterial pressure (MAP), cardiac index (CI) and heart rate (HR), with no changes in total peripheral resistance index or regional hemodynamics in SHR. Acute stress caused more remarkable hemodynamic changes in SHR. During stress, arotinolol decreased MAP, CI and HR, and reduced myocardial and skeletal muscle flow and splanchnic, renal, cerebral and cutaneous vascular resistance in SHR. Arotinolol's effects were much less in WKY. Stress also increased the plasma catecholamine and ANP levels in SHR. Arotinolol raised these hormones in both strains at rest and in SHR during stress. Thus, arotinolol treatment exerted greater suppressive effects on the resting and stressed hemodynamics in SHR, with associated increases in the plasma catecholamine and ANP levels.

  6. Use of lignocaine or nitroglycerine for blunting of hemodynamic stress response during electroconvulsive therapy

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    Muhammad Umar Zahoor

    2014-01-01

    Conclusion: NTG provided more hemodynamic stability in post-ECT period as compared to lignocaine which only prevented a surge in HR without any effect on MAP. We conclude that NTG can safely be instituted for anaesthesia in ECT patients for prevention of hemodynamic stress response.

  7. Hemodynamic stress response during laparoscopic cholecystectomy: Effect of two different doses of intravenous clonidine premedication

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    Deepshikha C Tripathi

    2011-01-01

    Full Text Available Background : Clonidine has emerged as an attractive premedication desirable in laparoscopic surgery wherein significant hemodynamic stress response is seen. The minimum safe and effective dose of intravenous clonidine to attenuate the hemodynamic stress response during laparoscopic surgery has however not yet been determined. Materials and Methods : This prospective, randomized, double-blind controlled study was conducted on 90 adults of ASA physical status I and II, scheduled for laparoscopic cholecystectomy under general anesthesia. Patients were randomized to one of the three groups (n= 30. Group I received 100 ml of normal saline, while groups II and III received 1 μg/ kg and 2 μg/ kg of clonidine respectively, intravenous, in 100 ml of normal saline along. All patients received glycopyrrolate 0.004 mg/kg and tramadol 1.5 mg/kg intravenously, 30 min before induction. Hemodynamic variables (heart rate, systolic, diastolic, mean arterial pressure, SpO2, and sedation score were recorded at specific timings. MAP above 20% from baseline was considered significant and treated with nitroglycerine. Results : In group I, there was a significant increase in hemodynamic variables during intubation pneumoperitoneum and extubation (P<0.001. Clonidine given 1 μg/kg intravenous attenuated hemodynamic stress response to pneumoperitoneum (P<0.05, but not that associated with intubation and extubation. Clonidine 2 μg/kg intravenous prevented hemodynamic stress response to pneumoperitoneum and that associated with intubation and extubation (P<0.05. As against 14 and 2 patients in groups I and II respectively, no patient required nitroglycerine infusion in group III. Conclusions : Clonidine, 2 μg/ kg intravenously, 30 min before induction is safe and effective in preventing the hemodynamic stress response during laparoscopic cholecystectomy.

  8. Hemodynamic responses to mental stress during salt loading

    DEFF Research Database (Denmark)

    Goyal, Maria Gefke; Christensen, Niels Juel; Bech, Per

    2017-01-01

    ) during preparation for a medical exam (prolonged stress) and (ii) outside the exam period (low stress). All subjects consumed a controlled diet for 3 days with low- or high-salt content in randomized order. The subjective stress was measured by Spielberger's State-Trait Anxiety Inventory-Scale, SCL...

  9. Hemodynamic responses to mental stress during salt loading.

    Science.gov (United States)

    Gefke, Maria; Christensen, Niels Juel; Bech, Per; Frandsen, Erik; Damgaard, Morten; Asmar, Ali; Norsk, Peter

    2017-11-01

    The purpose was to examine whether prolonged moderate stress associated with a student exam would increase the blood pressure response to a salt load in young healthy normotensive individuals. Ten healthy young subjects were examined at two different occasions in random order (i) during preparation for a medical exam (prolonged stress) and (ii) outside the exam period (low stress). All subjects consumed a controlled diet for 3 days with low- or high-salt content in randomized order. The subjective stress was measured by Spielberger's State-Trait Anxiety Inventory-Scale, SCL Symptom Checklist for stress and the Visual Analogue Scale. On each level of stress, 24-h ambulatory blood pressure and cardiac output (CO) were measured. Furthermore, plasma norepinephrine (NE), epinephrine (E) and plasma renin activity (PRA) were measured. Twenty-four-hour ABP, 24-h heart rate, CO as well as plasma levels of NE, E and PRA remained unchanged by changes in stress level. Day-night reduction in SAP was significantly larger during moderate stress and high-salt intake; however, no significant difference was observed during daytime and night-time. Individual increase in mental stress correlated significantly with an individual decrease in PRA (SCL-17, r = -0·80, Pstress over a period of time in young healthy normotensive individuals does not lead to changes in 24-h ABP. However, the augmented reduction in day-to-night systolic blood pressure during high-salt intake and moderate stress may indicate that stress affects blood pressure regulation. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  10. Regional and systemic hemodynamic responses following the creation of a murine arteriovenous fistula

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    Kang, Lu; Yamada, Satsuki; Hernandez, Melissa C.; Croatt, Anthony J.; Grande, Joseph P.; Juncos, Julio P.; Vercellotti, Gregory M.; Hebbel, Robert P.; Katusic, Zvonimir S.; Terzic, Andre

    2011-01-01

    The study of hemodynamic alterations following the creation of an arteriovenous fistula (AVF) is relevant to vascular adaptive responses and hemodialysis access dysfunction. This study examined such alterations in a murine AVF created by anastomosing the carotid artery to the jugular vein. AVF blood flow was markedly increased due to reduced AVF vascular resistance. Despite such markedly increased basal blood flow, AVF blood flow further increased in response to acetylcholine. This AVF model exhibited increased cardiac output and decreased systemic vascular resistance; the kidney, in contrast, exhibited decreased blood flow and increased vascular resistance. Augmentation in AVF blood flow was attended by increased arterial heme oxygenase-1 (HO-1) mRNA and protein expression, the latter localized to smooth muscle cells of the AVF artery; AVF blood flow was substantially reduced in HO-1−/− mice compared with HO-1+/+ mice. Finally, in a murine model of a representative disease known to exhibit impaired hemodynamic responses (sickle cell disease), the creation of an AVF was attended by decreased AVF flow and impaired AVF function. We conclude that this AVF model exhibits markedly increased AVF blood flow, a vasodilatory reserve capacity, increased cardiac output, decreased renal blood flow, and a dependency on intact hemodynamic responses, in general, and HO-1 expression, in particular, in achieving and maintaining AVF blood flow. We suggest that these findings support the utility of this model in investigating the basis for and the consequences of hemodynamic stress, including shear stress, and the pathobiology of hemodialysis AVF dysfunction. PMID:21697243

  11. Systemic hemodynamic and regional circulatory effects of centrally administered endothelin-1 are mediated through ETA receptors

    NARCIS (Netherlands)

    S. Rebello (Sam); S. Roy (Santanu); P.R. Saxena (Pramod Ranjan); A. Gulati (Anil)

    1995-01-01

    textabstractCentral endothelin (ET) has been implicated in the regulation of the cardiovascular system. The effect of intracerebroventricular (i.c.v.) administration of ET-1 or IRL 1620 (5, 15 and 45 ng) on the systemic hemodynamics and regional circulation was studied in anesthetized rats using a

  12. Protective Effects of Methylsulfonylmethane on Hemodynamics and Oxidative Stress in Monocrotaline-Induced Pulmonary Hypertensive Rats

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    Sadollah Mohammadi

    2012-01-01

    Full Text Available Methylsulfonylmethane (MSM is naturally occurring organic sulfur that is known as a potent antioxidant/anti-inflammatory compound. The aim of this study was to investigate the effect of MSM on hemodynamics functions and oxidative stress in rats with monocrotaline- (MCT- induced pulmonary arterial hypertension (PAH. Wistar rats were randomly assigned to 38-days treatment. MSM was administered to rats at 100, 200, and 400 mg/kg/day doses 10 days before a single dose of 60 mg/kg, IP, MCT. Hemodynamics of ventricles were determined by Powerlab AD instrument. Blood samples were obtained to evaluate changes in the antioxidative system including activities of catalase (CAT, superoxide dismutase (SOD, glutathione peroxidase (GPx, and the level of reduced glutathione (GSH and malondialdehyde (MDA. Improvements in cardiopulmonary hemodynamics were observed in the MSM-treated pulmonary arterial hypertensive rats, with a significant reduction in right ventricular systolic pressure (RSVP and an increase in the mean arterial pressure (MAP. The values of CAT, SOD, GSH-px activities, and GSH were significantly lower in MCT-induced PAH (P<0.01, but they were recovered to control levels of MSM-treated groups. Our present results suggest that long-term administration of the MSM attenuates MCT-induced PAH in rats through modulation of oxidative stress and antioxidant defense.

  13. WEB downloadable software for training in cardiovascular hemodynamics in the (3-D stress echo lab

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    Arpesella Giorgio

    2010-11-01

    Full Text Available Abstract When a physiological (exercise stress echo is scheduled, interest focuses on wall motion segmental contraction abnormalities to diagnose ischemic response to stress, and on left ventricular ejection fraction to assess contractile reserve. Echocardiographic evaluation of volumes (plus standard assessment of heart rate and blood pressure is ideally suited for the quantitative and accurate calculation of a set of parameters allowing a complete characterization of cardiovascular hemodynamics (including cardiac output and systemic vascular resistance, left ventricular elastance (mirroring left ventricular contractility, theoretically independent of preload and afterload changes heavily affecting the ejection fraction, arterial elastance, ventricular arterial coupling (a central determinant of net cardiovascular performance in normal and pathological conditions, and diastolic function (through the diastolic mean filling rate. All these parameters were previously inaccessible, inaccurate or labor-intensive and now become, at least in principle, available in the stress echocardiography laboratory since all of them need an accurate estimation of left ventricular volumes and stroke volume, easily derived from 3 D echo. Aims of this paper are: 1 to propose a simple method to assess a set of parameters allowing a complete characterization of cardiovascular hemodynamics in the stress echo lab, from basic measurements to calculations 2 to propose a simple, web-based software program, to learn and training calculations as a phantom of the everyday activity in the busy stress echo lab 3 to show examples of software testing in a way that proves its value. The informatics infrastructure is available on the web, linking to http://cctrainer.ifc.cnr.it

  14. Coupled simulation of vascular growth and remodeling, hemodynamics and stress-mediated mechanotransduction

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    Wu, Jiacheng; Shadden, Shawn C.

    2015-11-01

    A computational framework to couple vascular G&R, blood flow simulation and stress-mediated mechanotransduction is derived for patient specific geometry. A hyperelastic constitutive relation is considered for vascular material and vessel wall is modeled via constrained mixture theory. The coupled simulation is divided into three time scales - G&R (weeks-years), hemodynamics (seconds) and stress-mediated mechanotransduction (much less than 1 second). G&R is simulated and vessel wall deformation (and tension) is computed to obtain the current vessel geometry, which defines the new boundary for blood flow. Hemodynamics are then simulated in the updated domain to calculate WSS field. A system of ODE's is derived based on conservation law and phenomenological models to describe the signaling pathways from mechanical stimuli (WSS, wall tension) to mass production rate of vascular constituents, which, in turn, changes the kinetics of G&R. To reduce computation cost, blood flow is only simulated when G&R causes significant change to geometry, and steady state response of the ODE system for mechanotransduction is used to characterize the influence of WSS and wall tension on G&R, due to separation of three time scales.

  15. Mechanisms underlying hemodynamic and neuroendocrine stress reactivity at different phases of the menstrual cycle.

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    Gordon, Jennifer L; Girdler, Susan S

    2014-04-01

    This study examined the association of menstrual cycle phase with stress reactivity as well as the hormonal and neuroendocrine mechanisms contributing to cycle effects. Fifty-seven women underwent a modified Trier Social Stress Test during the early follicular, late follicular, and luteal phases of the menstrual cycle. Greater increases in cardiac index (CI) and greater decreases in vascular resistance index (VRI) during speech were observed in the luteal phase relative to other phases, while greater increases in epinephrine (EPI) was observed during the late follicular and luteal phases compared to the early follicular phase. Luteal phase estradiol predicted luteal EPI reactivity but not CI or VRI reactivity, while luteal phase EPI reactivity predicted luteal phase CI and VRI reactivity. Thus, cycle-related changes in EPI reactivity may be a stronger determinant of cycle effects on hemodynamic reactivity than sex hormones per se. Copyright © 2014 Society for Psychophysiological Research.

  16. Hemodynamic shear stress stimulates migration and extravasation of tumor cells by elevating cellular oxidative level.

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    Ma, Shijun; Fu, Afu; Chiew, Geraldine Giap Ying; Luo, Kathy Qian

    2017-03-01

    Cancer cells are shed into the blood stream and are exposed to hemodynamic shear stress during metastasis. It has been shown that shear stress can destroy circulating tumor cells (CTCs) both in vitro and in vivo. However, it remains unclear whether shear stress can modulate the properties and functions of tumor cells in a manner that might help CTCs to exit circulation. In this study, we established a microfluidic circulatory system to apply physiological fluid shear stress on breast cancer cells and demonstrated that an arterial level of shear stress significantly enhanced tumor cell migration in transwell and wound healing assays, and enhanced extravasation in a transendothelial assay. Circulatory treatment elevated the intracellular levels of reactive oxygen species (ROS), which is an early and indispensable event for activating the extracellular signal-regulated kinases (ERK1/2). Subsequently, ERK1/2 activation promoted the migration of tumor cells and enhanced their extravasation. Finally, reducing cellular ROS production suppressed tumor cell extravasation in both a transendothelial assay and a zebrafish model. This new understanding of how fluid shear stress promotes tumor cell migration has important implications in cancer treatment and can help us to identify potential therapeutic targets for inhibiting tumor progression. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Impaired cardiac contractility response to hemodynamic stress in S100A1-deficient mice.

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    Du, Xiao-Jun; Cole, Timothy J; Tenis, Nora; Gao, Xiao-Ming; Köntgen, Frank; Kemp, Bruce E; Heierhorst, Jörg

    2002-04-01

    Ca(2+) signaling plays a central role in cardiac contractility and adaptation to increased hemodynamic demand. We have generated mice with a targeted deletion of the S100A1 gene coding for the major cardiac isoform of the large multigenic S100 family of EF hand Ca(2+)-binding proteins. S100A1(-/-) mice have normal cardiac function under baseline conditions but have significantly reduced contraction rate and relaxation rate responses to beta-adrenergic stimulation that are associated with a reduced Ca(2+) sensitivity. In S100A1(-/-) mice, basal left-ventricular contractility deteriorated following 3-week pressure overload by thoracic aorta constriction despite a normal adaptive hypertrophy. Surprisingly, heterozygotes also had an impaired response to acute beta-adrenergic stimulation but maintained normal contractility in response to chronic pressure overload that coincided with S100A1 upregulation to wild-type levels. In contrast to other genetic models with impaired cardiac contractility, loss of S100A1 did not lead to cardiac hypertrophy or dilation in aged mice. The data demonstrate that high S100A1 protein levels are essential for the cardiac reserve and adaptation to acute and chronic hemodynamic stress in vivo.

  18. [Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery].

    Science.gov (United States)

    García-Hernández, J A; Aldemira-Liz, A; Martínez-López, A I; Cayuela, A; Charlo-Molina, M T; Cano-Franco, J; Loscertales-Abril, M

    2013-10-01

    Regional cerebral oxygen saturation (rSO₂) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO₂ correlated significantly with the other parameters. The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO₂ correlated positively with both central venous oxygen saturation (r=0.73, P 0.4) between the rSO₂ and central venous oxygen saturation, and between the rSO₂ and oxygen extraction ratio. Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  19. Effects of different levels of end-expiratory pressure on hemodynamic, respiratory mechanics and systemic stress response during laparoscopic cholecystectomy.

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    Sen, Oznur; Erdogan Doventas, Yasemin

    General anesthesia causes reduction of functional residual capacity. And this decrease can lead to atelectasis and intrapulmonary shunting in the lung. In this study we want to evaluate the effects of 5 and 10cmH2O PEEP levels on gas exchange, hemodynamic, respiratory mechanics and systemic stress response in laparoscopic cholecystectomy. American Society of Anesthesiologist I-II physical status 43 patients scheduled for laparoscopic cholecystectomy were randomly selected to receive external PEEP of 5cmH2O (PEEP 5 group) or 10cmH2O PEEP (PEEP 10 group) during pneumoperitoneum. Basal hemodynamic parameters were recorded, and arterial blood gases (ABG) and blood sampling were done for cortisol, insulin and glucose level estimations to assess the systemic stress response before induction of anesthesia. Thirty minutes after the pneumoperitoneum, the respiratory and hemodynamic parameters were recorded again and ABG and sampling for cortisol, insulin, and glucose levels were repeated. Lastly hemodynamic parameters were recorded; ABG analysis and sampling for stress response levels were taken after 60minutes from extubation. There were no statistical differences between the two groups about hemodynamic and respiratory parameters except mean airway pressure (Pmean). Pmean, compliance and PaO2; pH values were higher in 'PEEP 10 group'. Also, PaCO2 values were lower in 'PEEP 10 group'. No differences were observed between insulin and lactic acid levels in the two groups. But postoperative cortisol level was significantly lower in 'PEEP 10 group'. Ventilation with 10cmH2O PEEP increases compliance and oxygenation, does not cause hemodynamic and respiratory complications and reduces the postoperative stress response. Copyright © 2016 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  20. [Effects of different levels of end-expiratory pressure on hemodynamic, respiratory mechanics and systemic stress response during laparoscopic cholecystectomy].

    Science.gov (United States)

    Sen, Oznur; Erdogan Doventas, Yasemin

    General anesthesia causes reduction of functional residual capacity. And this decrease can lead to atelectasis and intrapulmonary shunting in the lung. In this study we want to evaluate the effects of 5 and 10cmH2O PEEP levels on gas exchange, hemodynamic, respiratory mechanics and systemic stress response in laparoscopic cholecystectomy. American Society of Anesthesiologist I-II physical status 43 patients scheduled for laparoscopic cholecystectomy were randomly selected to receive external PEEP of 5cmH2O (PEEP 5 group) or 10cmH2O PEEP (PEEP 10 group) during pneumoperitoneum. Basal hemodynamic parameters were recorded, and arterial blood gases (ABG) and blood sampling were done for cortisol, insulin and glucose level estimations to assess the systemic stress response before induction of anesthesia. Thirty minutes after the pneumoperitoneum, the respiratory and hemodynamic parameters were recorded again and ABG and sampling for cortisol, insulin, and glucose levels were repeated. Lastly hemodynamic parameters were recorded; ABG analysis and sampling for stress response levels were taken after 60minutes from extubation. There were no statistical differences between the two groups about hemodynamic and respiratory parameters except mean airway pressure (Pmean). Pmean, compliance and PaO2; pH values were higher in 'PEEP 10 group'. Also, PaCO2 values were lower in 'PEEP 10 group'. No differences were observed between insulin and lactic acid levels in the two groups. But postoperative cortisol level was significantly lower in 'PEEP 10 group'. Ventilation with 10cmH2O PEEP increases compliance and oxygenation, does not cause hemodynamic and respiratory complications and reduces the postoperative stress response. Copyright © 2016 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  1. Systemic and regional hemodynamic effects of enalaprilat infusion in experimental normotensive sepsis

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    L. Rahal

    Full Text Available Angiotensin-converting enzyme inhibitors have been shown to improve splanchnic perfusion in distinct shock states. We hypothesized that enalaprilat potentiates the benefits of early fluid resuscitation in severe experimental sepsis, particularly in the splanchnic region. Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over a period of 30 min. Thereafter, two interventions were performed: fluid infusion (normal saline, 32 mL/kg over 30 min and enalaprilat infusion (0.02 mg kg-1 min-1 for 60 min in randomized groups. The following groups were studied: controls (fluid infusion, N = 4, E1 (enalaprilat infusion followed by fluid infusion, N = 5 and E2 (fluid infusion followed by enalaprilat infusion, N = 5. All animals were observed for a 120 min after bacterial infusion. Mean arterial pressure, cardiac output (CO, portal vein blood flow (PVBF, systemic and regional oxygen-derived variables, and lactate levels were measured. Rapid and progressive reductions in CO and PVBF were induced by the infusion of live bacteria, while minor changes were observed in mean arterial pressure. Systemic and regional territories showed a significant increase in oxygen extraction and lactate levels. Widening venous-arterial and portal-arterial pCO2 gradients were also detected. Fluid replacement promoted transient benefits in CO and PVBF. Enalaprilat after fluid resuscitation did not affect systemic or regional hemodynamic variables. We conclude that in this model of normotensive sepsis inhibition of angiotensin-converting enzyme did not interfere with the course of systemic or regional hemodynamic and oxygen-derived variables.

  2. Systemic and regional hemodynamic effects of enalaprilat infusion in experimental normotensive sepsis

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    L. Rahal

    2006-09-01

    Full Text Available Angiotensin-converting enzyme inhibitors have been shown to improve splanchnic perfusion in distinct shock states. We hypothesized that enalaprilat potentiates the benefits of early fluid resuscitation in severe experimental sepsis, particularly in the splanchnic region. Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over a period of 30 min. Thereafter, two interventions were performed: fluid infusion (normal saline, 32 mL/kg over 30 min and enalaprilat infusion (0.02 mg kg-1 min-1 for 60 min in randomized groups. The following groups were studied: controls (fluid infusion, N = 4, E1 (enalaprilat infusion followed by fluid infusion, N = 5 and E2 (fluid infusion followed by enalaprilat infusion, N = 5. All animals were observed for a 120 min after bacterial infusion. Mean arterial pressure, cardiac output (CO, portal vein blood flow (PVBF, systemic and regional oxygen-derived variables, and lactate levels were measured. Rapid and progressive reductions in CO and PVBF were induced by the infusion of live bacteria, while minor changes were observed in mean arterial pressure. Systemic and regional territories showed a significant increase in oxygen extraction and lactate levels. Widening venous-arterial and portal-arterial pCO2 gradients were also detected. Fluid replacement promoted transient benefits in CO and PVBF. Enalaprilat after fluid resuscitation did not affect systemic or regional hemodynamic variables. We conclude that in this model of normotensive sepsis inhibition of angiotensin-converting enzyme did not interfere with the course of systemic or regional hemodynamic and oxygen-derived variables.

  3. GATA4 mediates activation of the B-type natriuretic peptide gene expression in response to hemodynamic stress.

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    Marttila, M; Hautala, N; Paradis, P; Toth, M; Vuolteenaho, O; Nemer, M; Ruskoaho, H

    2001-11-01

    To identify the mechanisms that couple hemodynamic stress to alterations in cardiac gene expression, DNA constructs containing the rat B-type natriuretic peptide (BNP) promoter were injected into the myocardium of rats, which underwent bilateral nephrectomy or were sham-operated. Ventricular BNP mRNA levels were induced about 4-fold; and the BNP reporter construct containing the proximal 2200 bp, 5-fold, in response to 1-d nephrectomy. Deletion of sequences between bp -2200 and -114 did not affect basal or inducible activity of the BNP promoter. An activator protein-1-like site and two tandem GATA elements are located within this 114-bp sequence. Both deletion and mutation of the AP-1-like motif decreased basal activity but did not abolish the response to nephrectomy. In contrast, mutation or deletion of -90 bp GATA-sites abrogated the response to hemodynamic stress. The importance of these GATA elements to BNP promoter activation was further confirmed by the corresponding 38-bp oligonucleotide conferring hemodynamic stress responsiveness to a minimal BNP promoter. In gel mobility shift assays, nephrectomy increased left ventricular BNP GATA4 binding activity significantly. In conclusion, GATA elements are necessary and sufficient to confer transcriptional activation of BNP gene in response to hemodynamic stress.

  4. [Effect of Oral Rehydration Therapy before General Anesthesia on Satisfaction, Stress Response, and Hemodynamics in Surgical Patients for Laparoscopic Colectomy].

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    Inoda, Ayako; Nagata, Hirofumi; Otsuka, Koki; Suzuki, Kenji

    2015-03-01

    The recommended intake of clear liquids until 2 hours before surgery is reportedly safe and effective. We investigated whether oral rehydration therapy before surgery had improved satisfaction, stress response, and hemodynamics in patients during perioperative period. Patients scheduled to undergo laparoscopic colectomy were enrolled and randomly divided into 2 groups. The oral rehydration therapy (ORT) group (29 cases) was allowed to drink clear liquids until 2 hours before anesthesia induction and the control group (29 cases) fasted from 21 : 00 the night before surgery. All patients entered the operating room at 8: 40. Patient satisfaction was examined after admission to the operating room. The volume and pH of gastric fluid were measured after anesthetic induction. The serum concentrations of cortisol and catecholamine were measured as stress response indicators after anesthetic induction and at the completion of surgery. Intraoperative hemodynamics was also recorded. There were no differences in patient satisfaction, stress response, and hemodynamics between the 2 groups. Intraoperative urine volume was significantly larger in the ORT group. Vomiting and aspiration were not observed in any patient Oral rehydration therapy until 2 hours before surgery seemed safe but did not improve satisfaction, stress response, and hemodynamics in perioperative patients.

  5. Influence of different anesthesia methods on stress reaction and hemodynamics for elderly orthopedics patients during operations

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    Lin Li

    2017-07-01

    Full Text Available Objective: To study the influence of general anesthesia, epidural anesthesia and combined spinal and epidural anesthesia method on stress reaction and hemodynamics for elderly orthopedics patients during operations. Methods: A total of 90 cases of elder patients who received orthopedic operations were randomly divided to group A, B and C, with 30 cases per group. Three groups of patients were separately given by general anesthesia, epidural anesthesia and combined spinal and epidural anesthesia for operations; The variations of adrenocorticotrophic hormone (ACTH, Cortisol (Cor, β-endorphin (β-EP, Angiotensin- Ⅱ(Ang-Ⅱ, heart rate (HR and blood pressure (SBP, DBP on patients in three groups before anesthesia (T0, during skin incision (T1, after skin incision (T2 and extubation after operation (T3 were compared and analyzed. Results: During T1, T2, ACTH, Cor, β-EP and Ang-Ⅱlevels in 3 groups of patients were significantly higher than those during T0; SBP and DBP were significantly lower than that during T0; HR during T2 was significantly lower than that during T0; During T3, every index in 3 groups were recovered to levels close to that during T0; During T1, T2, ACTH, Cor, β-EP, Ang-Ⅱ levels in group B and C were significantly lower than that in group A. And levels in C was lower than that in B; SBP and DBP in group B and C were significantly higher than A. No HR statistical significance appeared between each group. Conclusions: During clinical anesthesia, we should choose suitable anesthesia method combined with actual situations of patients. Combined spinal and epidural anesthesia had a slight influence on hemodynamics of elder orthopedics patients during operation, and it could effectively alleviate stress reaction during operation.

  6. [Effect of cupping on hemodynamic levels in the regional sucked tissues in patients with lumbago].

    Science.gov (United States)

    Tang, Xiao; Xiao, Xue-Hua; Zhang, Guo-Qing

    2012-10-01

    To observe hemodynamic changes in the local sucked tissue of lower back undergoing negative pressure after cupping in patients with lumbago. Twenty-two lumbago outpatients were recruited in the present study and 32 sucked tissues accepted measurements. The cupping was applied to the tenderpoint of the patients' lower back for 10 min by using a glass-mug (5 cm in diameter). Hemodynamic indexes [peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI)] of the sucked skin and subcutaneous tissues at the lower back were detected before and after cupping by using a color Doppler flow imaging. After cupping intervention at the lower back, the PSV [(14.2 +/- 1.8) cm/s] and EDV [(5.5 +/- 0.7) cm/s] levels were increased significantly in comparison with those [(5.9 +/- 0.9) and (1.9 +/- 0.3) cm/s] before cupping (P cupping (0.61 +/- 0.05 vs 0.68 +/- 0.06, P Cupping therapy can increase the peak systolic velocity and end-diastolic velocity and lower vascular resistance of the subcutaneous arterioles in the regional tissue, which may contribute to its effect in relieving lumbago.

  7. Assessment of turbulent viscous stress using ICOSA 4D Flow MRI for prediction of hemodynamic blood damage

    Science.gov (United States)

    Ha, Hojin; Lantz, Jonas; Haraldsson, Henrik; Casas, Belen; Ziegler, Magnus; Karlsson, Matts; Saloner, David; Dyverfeldt, Petter; Ebbers, Tino

    2016-12-01

    Flow-induced blood damage plays an important role in determining the hemodynamic impact of abnormal blood flow, but quantifying of these effects, which are dominated by shear stresses in highly fluctuating turbulent flow, has not been feasible. This study evaluated the novel application of turbulence tensor measurements using simulated 4D Flow MRI data with six-directional velocity encoding for assessing hemodynamic stresses and corresponding blood damage index (BDI) in stenotic turbulent blood flow. The results showed that 4D Flow MRI underestimates the maximum principal shear stress of laminar viscous stress (PLVS), and overestimates the maximum principal shear stress of Reynolds stress (PRSS) with increasing voxel size. PLVS and PRSS were also overestimated by about 1.2 and 4.6 times at medium signal to noise ratio (SNR) = 20. In contrast, the square sum of the turbulent viscous shear stress (TVSS), which is used for blood damage index (BDI) estimation, was not severely affected by SNR and voxel size. The square sum of TVSS and the BDI at SNR >20 were underestimated by less than 1% and 10%, respectively. In conclusion, this study demonstrated the feasibility of 4D Flow MRI based quantification of TVSS and BDI which are closely linked to blood damage.

  8. Hemodynamic stress distribution reflects ischemic clinical symptoms of patients with moyamoya disease.

    Science.gov (United States)

    Takahashi, Satoshi; Tanizaki, Yoshio; Kimura, Hiroaki; Akaji, Kazunori; Nakazawa, Masaki; Yoshida, Kazunari; Mihara, Ban

    2015-11-01

    Currently, the probability of diagnosing asymptomatic moyamoya disease is increasing. In this study, we consider a less invasive method for predicting future ischemic symptoms in patients with moyamoya disease. We reviewed cerebral blood flow (CBF)-related data obtained by xenon CT imaging (XeCT) in six patients with ischemic-type or asymptomatic moyamoya disease. The data were obtained as volume data using a 320-row CT, and applied to the automated region-of-interest-determining software (3DSRT) and converted to standardized images. Eight CBF-related parameters, including CBF value, cerebrovascular reserve capacity (CVRC), and hemodynamic distribution (hdSD), were compared between asymptomatic hemispheres and ischemic symptomatic hemispheres. A significant difference was determined by a two-sample t test. A difference with pmoyamoya disease. Thus, these parameters could be used as ischemic symptom markers for following patients with moyamoya disease. hdSD at rest is important because it is less invasive and can be performed without acetazolamide loading. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. The efficacy of labetalol vs dexmedetomidine for attenuation of hemodynamic stress response to laryngoscopy and endotracheal intubation.

    Science.gov (United States)

    El-Shmaa, Nagat S; El-Baradey, Ghada F

    2016-06-01

    To assess the effectiveness of labetalol vs dexmedetomidine for attenuation of hemodynamic stress response to laryngoscopy and endotracheal intubation. Prospective, randomized, controlled, observer-blinded study. This study was carried out in Tanta University Hospital. Ninety patients of both sexes; American Society of Anesthesiologists physical status I and II; age range from 20 to 60 years; scheduled for elective surgery under general anesthesia. Patients were divided into 3 groups (30 each). Group A received 1 μg/kg of dexmedetomidine as intravenous (IV) infusion, group B received labetalol 0.25mg/kg IV, and group C received 10mL saline IV. The groups were compared for heart rate (HR), mean arterial pressure (MAP), and rate pressure product (RPP). Hemodynamic parameters were recorded during the preinduction; after induction; at intubation; and at 1, 3, 5, 10, and 15minutes. The primary outcomes were hemodynamic changes (HR, MBP, and RPP), and the secondary outcome was propofol dose requirement for induction of general anaesthesia. Significant decrease (P labetalol without any deleterious effects. Furthermore, dexmedetomidine decreases dose of propofol for induction of anesthesia as guided by bispectral index. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Monitoring Local Regional Hemodynamic Signal Changes during Motor Execution and Motor Imagery Using Near-Infrared Spectroscopy

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    Naoki eIso

    2016-01-01

    Full Text Available The aim of this study was to clarify the topographical localization of motor-related regional hemodynamic signal changes during motor execution (ME and motor imagery (MI by using near-infrared spectroscopy (NIRS, as this technique is more clinically expedient than established methods (e.g. fMRI. Twenty right-handed healthy subjects participated in this study. The experimental protocol was a blocked design consisting of 3 cycles of 20 s of task performance and 30 s of rest. The tapping sequence task was performed with their fingers under 4 conditions: ME and MI with the right or left hand. Hemodynamic brain activity was measured with NIRS to monitor changes in oxygenated hemoglobin (oxy-Hb concentration. Oxy-Hb in the somatosensory motor cortex (SMC increased significantly only during contralateral ME and showed a significant interaction between task and hand. There was a main effect of hand in the left SMC. Although there were no significant main effects or interactions in the supplemental motor area (SMA and premotor area (PMA, oxy-Hb increased substantially under all conditions. These results clarified the topographical localization by motor-related regional hemodynamic signal changes during ME and MI by using NIRS.

  11. Comparison of hemodynamic and metabolic stress responses caused by endotracheal tube and Proseal laryngeal mask airway in laparoscopic cholecystectomy

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    Handan Güleç

    2012-01-01

    Full Text Available Background: We aimed to compare hemodynamic and endocrine alterations caused by stress response due to Proseal laryngeal mask airway and endotracheal tube usage in laparoscopic cholecystectomy. Materials and Methods: Sixty-three ASA I-II patients scheduled for elective laparoscopic cholecystectomy were included in the study. Patients were randomly allocated into two groups of endotracheal tube and Proseal laryngeal mask airway. Standard general anaesthesia was performed in both groups with the same drugs in induction and maintenance of anaesthesia. After anaesthesia induction and 20 minutes after CO 2 insufflations, venous blood samples were obtained for measuring adrenalin, noradrenalin, dopamine and cortisol levels. Hemodynamic and respiratory parameters were recorded at the 1 st , 5 th , 15 th , 30 th and 45 th minutes after the insertion of airway devices. Results: No statistically significant differences in age, body mass index, gender, ASA physical status, and operation time were found between the groups (p > 0.05. Changes in hemodynamic and respiratory parameters were not statistically significant when compared between and within groups (p > 0.05. Although no statistically significant differences were observed between and within groups when adrenalin, noradrenalin and dopamine values were compared, serum cortisol levels after CO 2 insufflation in PLMA group were significantly lower than the ETT group (p = 0.024. When serum cortisol levels were compared within groups, cortisol levels 20 minutes after CO 2 insufflation were significantly higher (46.1 (9.5-175.7 and 27.0 (8.3-119.4 in the ETT and PLMA groups, respectively than cortisol levels after anaesthesia induction (11.3 (2.8-92.5 and 16.6 (4.4-45.4 in the ETT and PLMA groups, respectively in both groups (p = 0.001. Conclusion: PLMA usage is a suitable, effective and safe alternative to ETT in laparoscopic cholecystectomy patients with lower metabolic stress.

  12. Immediate effects of chest physiotherapy on hemodynamic, metabolic, and oxidative stress parameters in subjects with septic shock.

    Science.gov (United States)

    dos Santos, Rafael S; Donadio, Márcio V F; da Silva, Gabriela V; Blattner, Clarissa N; Melo, Denizar A S; Nunes, Fernanda B; Dias, Fernando S; Squizani, Eamim D; Pedrazza, Leonardo; Gadegast, Isabella; de Oliveira, Jarbas R

    2014-09-01

    Septic shock presents as a continuum of infectious events, generating tissue hypoxia and hypovolemia, and increased oxidative stress. Chest physiotherapy helps reduce secretion, improving dynamic and static compliance, as well as improving secretion clearance and preventing pulmonary complications. The purpose of this study was to evaluate the immediate effect of chest physiotherapy on hemodynamic, metabolic, inflammatory, and oxidative stress parameters in subjects in septic shock. We conducted a quasi-experimental study in 30 subjects in septic shock, who underwent chest physiotherapy, without associated heart diseases and with vasopressors physiotherapy. Thirty subjects with a mean age of 61.8 ± 15.9 y and Sequential Organ Failure Assessment of 8 (range 6-10) were included. Chest physiotherapy caused a normalization of pH (P = .046) and P(aCO2) (P = .008); reduction of lactate (P = .001); and an increase in P(aO2) (P = .03), arterial oxygen saturation (P = .02), and P(aO2)/F(IO2) (P = .034), 15 min after it was applied. The results indicate that chest physiotherapy has immediate effects, improving oxygenation and reducing lactate and oxidative damage in subjects in septic shock. However, it does not cause alterations in the inflammatory and hemodynamic parameters. Copyright © 2014 by Daedalus Enterprises.

  13. [Peculiarities of face regional hemodynamics in treatment of acute purulent jaw odontogenic periostitis].

    Science.gov (United States)

    Fedotov, S N; Sukhanov, A E; Konkina, M A; Iakovlev, V E

    2010-01-01

    53 patients were under observation with acute purulent jaw odontogenic periostitis. In 27 out of them after operation as drainage material strips of napkin were used, containing as the active components metronidazol, dimexide and sodium alginate. Curative process efficacy evaluation was done according to the data of hemodynamic study (determination of the artery's diameter, maximal systolic speed and index of circulatory resistance) of the magistral face arteries. It was established that in the group of patients with rational treatment blood circulation in face arterial vessels was restored most actively than in the control group with the use of traditional treatment scheme.

  14. Comparison of hemodynamic and stress testing variables in patients undergoing regadenoson stress myocardial perfusion imaging to regadenoson with adjunctive low-level exercise myocardial perfusion imaging.

    Science.gov (United States)

    Cabrera, Rafael; Husain, Zehra; Palani, Gurunanthan; Karthikeyan, Aarthee S; Choudhry, Zain; Dhanalakota, Sunita; Peterson, Ed; Ananthasubramaniam, Karthik

    2013-06-01

    Regadenoson (REG), a selective adenosine A2a receptor agonist, is becoming the preferred pharmacologic agent for stress myocardial perfusion imaging (MPI). Hemodynamic and stress variables, immediate safety and use of aminophylline when using REG combined with low-level exercise (REG WALK MPI) compared with REG MPI, have not been well studied and formed the basis of our study. Retrospective evaluation of patients who underwent REG MPI (n = 887) was compared to patients undergoing REG WALK MPI (n = 485) from January to November 2009. Patient demographics, hemodynamic parameters, REG MPI data, side effects, immediate major clinical events, and use of aminophylline were evaluated. Patients in REG WALK MPI group tended to be younger, male and obese compared to patients in REG MPI group. REG WALK MPI patients had higher stress heart rate (103 ± 20.5 vs 84 ± 19 bpm, P = .001), higher heart rate reserve (36.3 ± 19 vs 14.7 ± 15.5 bpm, P < .001), and greater systolic blood pressure rise (4.8 ± 21.3 vs -8.9 ± 19.8 mm Hg, P < .001), compared to REG MPI patients. No major adverse events were reported immediately after REG WALK MPI. There were no differences in drug-related side effects in between the two groups; however, the use of aminophylline was lower in REG WALK MPI Group (5.6% vs 11.4%, P = .001). REG WALK MPI gives more favorable hemodynamic response with lesser use of aminophylline and no increase in adverse events when compared with REG MPI.

  15. Effect of stellate ganglion block on hemodynamics and stress responses during CO2-pneumoperitoneum in elderly patients.

    Science.gov (United States)

    Chen, Yong-Quan; Xie, Yu-Yizi; Wang, Bin; Jin, Xiao-Ju

    2017-02-01

    Elderly patients undergoing elective laparoscopic cholecystectomy (LC) were given right stellate ganglion block (RSGB) to observe its effects on the hemodynamics and stress response during carbon dioxide (CO2)-pneumoperitoneum. A randomized, single-blinded, and placebo-controlled study. University-affiliated teaching hospital. Sixty patients (aged 65-78years; weight, 45-75kg; American Society of Anesthesiologists (ASA) physical status classification, class I or II) undergoing elective LC. Right stellate ganglion block was performed via C7 access using 10mL of 1% lidocaine in all patients. The patients' heart rate (HR) and mean arterial pressure (MAP) were recorded before the block (T0), 5min following pneumoperitoneum (T1), 30min following pneumoperitoneum (T2), 5min following the deflation of pneumoperitoneum (T3), and upon completion of the surgery (T4). Additionally, the concentrations of epinephrine (E), norepinephrine (NE) and cortisol (COR) were detected in arterial blood at each time point by enzyme-linked immunosorbent assay. For control group, the MAP and RPP (RPP=SBP×HR) were significantly elevated at T1~3 (Pblock can reduce blood catecholamines during CO2-pneumoperitoneum to maintain perioperative hemodynamic stability and prevent adverse cardiovascular events in elderly patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models.

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    Jared C Weddell

    Full Text Available Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.

  17. REGIONAL HEMODYNAMICS IN DIFFERENT TYPES OF SURGICAL TREATMENT OF DIAPHYSEAL FRACTURES OF THE SHIN BONE

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    V. V. Pisarev

    2012-01-01

    Full Text Available 82 patients were examined with the tibia fractures. Osteosynthesis with the help of plates was executed by 40 patients, osteosynthesis with the help of hinges with blocking was executed by 42 patients. The methods of duplex scanning of vessels and reovazografic inspection were used for studying of the blood circulation in tibia. Researches were conducted on the 5th and the 10th days in 1, 2, 3 and 4 months after the operation. It was established that the surgical treatment of the tibia fractures without any difference in using various methods of the broken fragments fixation in the early postoperative period (first 10 days leads to a decrease in the level of arterial blood flow as a result of the vessels hypotonia. The absence of postoperative immobilization and early loading lead to the more rapid restoration of the initial indices of hemodynamics. Blood flow changes are least expressed and more rapidly restored during the closed reposition osteosynthesis with the help of hinges. The reaction of the vascular system of periosteum in the process of the regeneration of the tibia tissues does not depend on the method of the surgical treatment.

  18. B-Type Natriuretic Peptide Reactivity to Mental Stress and Exercise: Role of Obesity and Hemodynamics

    Science.gov (United States)

    2009-08-25

    little known regarding the effects of mental or emotional stress on BNP levels. However, there is evidence in the human and animal literature that...1 h (for BNP) and 3 h (for ANP) following the onset of immobilization stress (90). This study provides evidence in an animal model for a possible...open circuit spirometry (Oxycon Mobile, VIASYS Healthcare Inc.). With open circuit spirometry , the participant wears a mask that allows them to

  19. Assessment of Cerebral Hemodynamic Changes in Pediatric Patients with Moyamoya Disease Using Probabilistic Maps on Analysis of Basal/Acetazolamide Stress Brain Perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Young; Lee, Jae Sung; Kim, Seung Ki; Wang, Kyu Chang; Cho, Byung Kyu; Chung, June Key; Lee, Myung Chul; Lee, Dong Soo [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Total fifty six (M:F=33:24, age 6.7{+-}3.2 years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was 33{+-}21 months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal

  20. The Effects of Hemodynamic Shear Stress on Stemness of Acute Myelogenous Leukemia (AML)

    Science.gov (United States)

    Raddatz, Andrew; Triantafillu, Ursula; Kim, Yonghyun (John)

    2015-11-01

    Cancer stem cells (CSCs) have recently been identified as the root cause of tumors generated from cancer cell populations. This is because these CSCs are drug-resistant and have the ability to self-renew and differentiate. Current methods of culturing CSCs require much time and money, so cancer cell culture protocols, which maximize yield of CSCs are needed. It was hypothesized that the quantity of Acute myelogenous leukemia stem cells (LSCs) would increase after applying shear stress to the leukemia cells based on previous studies with breast cancer in bioreactors. The shear stress was applied by pumping the cells through narrow tubing to mimic the in vivo bloodstream environment. In support of the hypothesis, shear stress was found to increase the amount of LSCs in a given leukemia population. This work was supported by NSF REU Site Award 1358991.

  1. Comparison of arbutamine stress and treadmill exercise thallium-201 SPECT: Hemodynamics, safety profile and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kiat, H.; Berman, D.S. [Cedars-Sinai Medical Centre, Los Angeles, California, LA (United States)

    1998-02-01

    Full text: Arbutamine (ARB), a new pharmacologic stress agent with enhanced chronotropic property compared to dobutamine, was compared with treadmill (TM) exercise testing (Ex) in a multicenter study using thallium-201 (Tl) SPECT. Of the total of 184 patients who underwent ARB, 69 also had TM stress and quantitative coronary angiography. Fifty-eight patients with a low pretest likelihood of CAD also underwent ARB study for evaluation of test specificity (normalcy rate). Tl scans were scored by a central laboratory using a 20 segment (seg)/scan visual analysis (5 point system: 0=normal, 4-absent uptake). Maximum heart rate (HR) by ARB and Ex was 122 vs 141 bpm (p<0.05). Mean %HR change from baseline was similar (79% vs 82%, respectively, p=ns). Maximum systolic BP for ARB and Ex was 173 vs 175 mmHg, and mean % change from baseline was 24% vs 28% (p=ns). Sensitivity for detecting CAD (270% stenosis) by ARB Tl was 94% and 97% by Ex Tl (p=ns). Stress Tl SPECT segmental agreement for presence of defect between ARB and Ex was 92% (kappa=0.8, p<0.001). Exact segmental stress Tl score (0-4 grading) agreement was 83 % (kappa=0.7, p<0.001). Among 346 segs with stress defects by both ARB and Ex defect reversibility agreement was 86% (kappa=0.7, p<0.001). The normalcy rate for ARB TI-SPECT among patients with a low likelihood of CAD was 90%. Adverse events were mostly mild (tremor: 23%, flushing: 10%, headache: 10%, paraesthesia: 8%, dizziness: 8%, hot flushes: 4%). Arrhythimia of clinical concern occurred in 8% (10/122) of ARB patients who had cardiac catheterisation and in 1.4% (1/69) of patients who had stress Tl. Of all 184 patients with ARB stress, ARB was discontinued due to arrhythmia in 7(5%) and 1 patient had IV Metoprolol for frequent ventricular couplets. Sustained arrhythmias were not observed

  2. Effects of age-associated regional changes in aortic stiffness on human hemodynamics revealed by computational modeling.

    Directory of Open Access Journals (Sweden)

    Federica Cuomo

    Full Text Available Although considered by many as the gold standard clinical measure of arterial stiffness, carotid-to-femoral pulse wave velocity (cf-PWV averages material and geometric properties over a large portion of the central arterial tree. Given that such properties may evolve differentially as a function of region in cases of hypertension and aging, among other conditions, there is a need to evaluate the potential utility of cf-PWV as an early diagnostic of progressive vascular stiffening. In this paper, we introduce a data-driven fluid-solid-interaction computational model of the human aorta to simulate effects of aging-related changes in regional wall properties (e.g., biaxial material stiffness and wall thickness and conduit geometry (e.g., vessel caliber, length, and tortuosity on several metrics of arterial stiffness, including distensibility, augmented pulse pressure, and cyclic changes in stored elastic energy. Using the best available biomechanical data, our results for PWV compare well to findings reported for large population studies while rendering a higher resolution description of evolving local and global metrics of aortic stiffening. Our results reveal similar spatio-temporal trends between stiffness and its surrogate metrics, except PWV, thus indicating a complex dependency of the latter on geometry. Lastly, our analysis highlights the importance of the tethering exerted by external tissues, which was iteratively estimated until hemodynamic simulations recovered typical values of tissue properties, pulse pressure, and PWV for each age group.

  3. Numerical model of total artificial heart hemodynamics and the effect of its size on stress accumulation.

    Science.gov (United States)

    Marom, Gil; Chiu, Wei-Che; Slepian, Marvin J; Bluestein, Danny

    2014-01-01

    The total artificial heart (TAH) is a bi-ventricular mechanical circulatory support device that replaces the heart in patients with end-stage congestive heart failure. The device acts as blood pump via pneumatic activation of diaphragms altering the volume of the ventricular chambers. Flow in and out of the ventricles is controlled by mechanical heart valves. The aim of this study is to evaluate the flow regime in the TAH and to estimate the thrombogenic potential during systole. Toward that goal, three numerical models of TAHs of differing sizes, that include the deforming diaphragm and the blood flow from the left chamber to the aorta, are introduced. A multiphase model with injection of platelet particles is employed to calculate their trajectories. The shear stress accumulation in the three models are calculated along the platelets trajectories and their probability density functions, which represent the `thrombogenic footprint' of the device are compared. The calculated flow regime successfully captures the mitral regurgitation and the flows that open and close the aortic valve during systole. Physiological velocity magnitudes are found in all three models, with higher velocities and increased stress accumulation predicted for smaller devices.

  4. Hemodynamic mechanisms of the attenuated blood pressure response to mental stress after a single bout of maximal dynamic exercise in healthy subjects

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    F.J. Neves

    2012-07-01

    Full Text Available To determine the hemodynamic mechanisms responsible for the attenuated blood pressure response to mental stress after exercise, 26 healthy sedentary individuals (age 29 ± 8 years underwent the Stroop color-word test before and 60 min after a bout of maximal dynamic exercise on a treadmill. A subgroup (N = 11 underwent a time-control experiment without exercise. Blood pressure was continuously and noninvasively recorded by infrared finger photoplethysmography. Stroke volume was derived from pressure signals, and cardiac output and peripheral vascular resistance were calculated. Perceived mental stress scores were comparable between mental stress tests both in the exercise (P = 0.96 and control (P = 0.24 experiments. After exercise, the blood pressure response to mental stress was attenuated (pre: 10 ± 13 vs post: 6 ± 7 mmHg; P 0.05. In conclusion, a single bout of maximal dynamic exercise attenuates the blood pressure response to mental stress in healthy subjects, along with lower stroke volume and cardiac output, denoting an acute modulatory action of exercise on the central hemodynamic response to mental stress.

  5. Hemodynamic responses of eye movement desensitization and reprocessing in posttraumatic stress disorder.

    Science.gov (United States)

    Ohtani, Toshiyuki; Ohta ni, Toshiyuki; Matsuo, Koji; Kasai, Kiyoto; Kato, Tadafumi; Kato, Nobumasa

    2009-12-01

    Eye movement desensitization and reprocessing (EMDR) is an effective psychological intervention for posttraumatic stress disorder (PTSD). Trauma-related recall (Recall) with eye movements (EMs) is thought to reduce distress. However, the neural mechanisms underlying this process remain unknown. Thirteen patients with PTSD received EMDR treatment over the course of 2-10 weeks. We assessed the change in hemoglobin concentration in the lateral prefrontal cortex (PFC) during Recall with and without EM using multi-channel near-infrared spectroscopy (NIRS). Clinical diagnosis and improvement were evaluated using the Clinician-Administered PTSD Scale. Recall with EM was associated with a significant decrease in oxygenated hemoglobin concentration ([oxy-Hb]) in the lateral PFC as compared with Recall without EM. Longitudinally, [oxy-Hb] during Recall significantly decreased and the amount of decrease was significantly correlated with clinical improvement when the post-treatment data was compared with that of the pre-treatment. Our results suggest that performing EM during Recall reduces the over-activity of the lateral PFC, which may be part of the biological basis for the efficacy of EMDR in PTSD. NIRS may be a useful tool for objective assessment of psychological intervention in PTSD.

  6. Asiatic Acid Alleviates Hemodynamic and Metabolic Alterations via Restoring eNOS/iNOS Expression, Oxidative Stress, and Inflammation in Diet-Induced Metabolic Syndrome Rats

    Directory of Open Access Journals (Sweden)

    Poungrat Pakdeechote

    2014-01-01

    Full Text Available Asiatic acid is a triterpenoid isolated from Centella asiatica. The present study aimed to investigate whether asiatic acid could lessen the metabolic, cardiovascular complications in rats with metabolic syndrome (MS induced by a high-carbohydrate, high-fat (HCHF diet. Male Sprague-Dawley rats were fed with HCHF diet with 15% fructose in drinking water for 12 weeks to induce MS. MS rats were treated with asiatic acid (10 or 20 mg/kg/day or vehicle for a further three weeks. MS rats had an impairment of oral glucose tolerance, increases in fasting blood glucose, serum insulin, total cholesterol, triglycerides, mean arterial blood pressure, heart rate, and hindlimb vascular resistance; these were related to the augmentation of vascular superoxide anion production, plasma malondialdehyde and tumor necrosis factor-alpha (TNF-α levels (p < 0.05. Plasma nitrate and nitrite (NOx were markedly high with upregulation of inducible nitric oxide synthase (iNOS expression, but dowregulation of endothelial nitric oxide synthase (eNOS expression (p < 0.05. Asiatic acid significantly improved insulin sensitivity, lipid profiles, hemodynamic parameters, oxidative stress markers, plasma TNF-α, NOx, and recovered abnormality of eNOS/iNOS expressions in MS rats (p < 0.05. In conclusion, asiatic acid improved metabolic, hemodynamic abnormalities in MS rats that could be associated with its antioxidant, anti-inflammatory effects and recovering regulation of eNOS/iNOS expression.

  7. Ex vivo evidence for the contribution of hemodynamic shear stress abnormalities to the early pathogenesis of calcific bicuspid aortic valve disease.

    Directory of Open Access Journals (Sweden)

    Ling Sun

    Full Text Available The bicuspid aortic valve (BAV is the most common congenital cardiac anomaly and is frequently associated with calcific aortic valve disease (CAVD. The most prevalent type-I morphology, which results from left-/right-coronary cusp fusion, generates different hemodynamics than a tricuspid aortic valve (TAV. While valvular calcification has been linked to genetic and atherogenic predispositions, hemodynamic abnormalities are increasingly pointed as potential pathogenic contributors. In particular, the wall shear stress (WSS produced by blood flow on the leaflets regulates homeostasis in the TAV. In contrast, WSS alterations cause valve dysfunction and disease. While such observations support the existence of synergies between valvular hemodynamics and biology, the role played by BAV WSS in valvular calcification remains unknown. The objective of this study was to isolate the acute effects of native BAV WSS abnormalities on CAVD pathogenesis. Porcine aortic valve leaflets were subjected ex vivo to the native WSS experienced by TAV and type-I BAV leaflets for 48 hours. Immunostaining, immunoblotting and zymography were performed to characterize endothelial activation, pro-inflammatory paracrine signaling, extracellular matrix remodeling and markers involved in valvular interstitial cell activation and osteogenesis. While TAV and non-coronary BAV leaflet WSS essentially maintained valvular homeostasis, fused BAV leaflet WSS promoted fibrosa endothelial activation, paracrine signaling (2.4-fold and 3.7-fold increase in BMP-4 and TGF-β1, respectively, relative to fresh controls, catabolic enzyme secretion (6.3-fold, 16.8-fold, 11.7-fold, 16.7-fold and 5.5-fold increase in MMP-2, MMP-9, cathepsin L, cathepsin S and TIMP-2, respectively and activity (1.7-fold and 2.4-fold increase in MMP-2 and MMP-9 activity, respectively, and bone matrix synthesis (5-fold increase in osteocalcin. In contrast, BAV WSS did not significantly affect α-SMA and Runx2

  8. Fitter Women Did Not Have Attenuated Hemodynamic Responses to Psychological Stress Compared with Age-Matched Women with Lower Levels of Fitness.

    Directory of Open Access Journals (Sweden)

    Sisitha U Jayasinghe

    Full Text Available According to the 'cross stressor adaptation hypothesis', regular exercise acts as a buffer against the detrimental effects of stress. Nevertheless, evidence that higher levels of cardiorespiratory fitness moderate hemodynamic responses to acute psychological stress is inconclusive, especially in women. Women aged 30-50 years (in the mid-follicular phase of the menstrual cycle with higher (n = 17 and lower (n = 17 levels of fitness were subjected to a Trier Social Stress Test (TSST. Continuous, non-invasive measurements were made of beat-to-beat, systolic blood pressure (SBP, diastolic blood pressure (DBP, mean arterial pressure (MAP, heart rate (HR, stroke volume (SV, cardiac output (CO, left ventricular ejection time (LVET, maximum slope, pulse interval (PI and total peripheral resistance (TPR. Maximal oxygen consumption was significantly (p<0.001 higher in the 'higher fit' women. Lower fit women had higher fasting glucose, resting heart rate, waist to hip ratios and elevated serum triglyceride and cholesterol/ HDL ratios compared with higher fit women (p<0.05 for all. While all measured parameters (for both groupsdisplayed significant (p<0.001 responses to the TSST, only HR, PI and LVET differed significantly between higher and lower fit women (p<0.001 for all with the higher fit women having the larger response in each case. It was also found that higher fit women had significantly shorter time to recovery for maximum slope compared with the lower fit women. These findings provide little support for the notion that higher levels of cardiorespiratory fitness result in lower cardiovascular responsivity to psychological stress in women but may indicate that lower fit women have blunted responses to stress.

  9. The Sub-Crustal Stress Field in the Taiwan Region

    Directory of Open Access Journals (Sweden)

    Robert Tenzer and Mehdi Eshagh

    2015-01-01

    Full Text Available We investigate the sub-crustal stress in the Taiwan region. A tectonic configuration in this region is dominated by a collision between the Philippine oceanic plate and the Eurasian continental margin. The horizontal components of the sub-crustal stress are computed based on the modified _ formulae in terms of the stress function with a subsequent numerical differentiation. This modification increases the (degree-dependent convergence domain of the asymptotically-convergent series and consequently allows evaluating the stress components to a spectral resolution, which is compatible with currently available global crustal models. Moreover, the solution to the Vening _ (VMM inverse isostasy problem is explicitly incorporated in the stress function definition. The sub-crustal stress is then computed for a variable Moho geometry, instead of assuming only a constant Moho depth. The regional results reveal that the Philippine plate subduction underneath the Eurasian continental margin generates the shear sub-crustal stress along the Ryukyu Trench. Some stress anomalies associated with this subduction are also detected along both sides of the Okinawa Trough. A tensional stress along this divergent tectonic plate boundary is attributed to a back-arc rifting. The sub-crustal stress, which is generated by a (reverse subduction of the Eurasian plate under the Philippine plate, propagates along both sides of the Luzon (volcanic Arc. This stress field has a prevailing compressional pattern.

  10. Angiotensin II type 1 receptors and systemic hemodynamic and renal responses to stress and altered blood volume in conscious rabbits

    Directory of Open Access Journals (Sweden)

    Tony B. Xu

    2011-07-01

    Full Text Available We examined how systemic blockade of type 1 angiotensin (AT1- receptors affects reflex control of the circulation and the kidney. In conscious rabbits, the effects of candesartan on responses of systemic and renal hemodynamics and renal excretory function to acute hypoxia, mild hemorrhage and plasma volume expansion were tested. Candesartan reduced resting mean arterial pressure (MAP, -8 ± 2% without significantly altering cardiac output (CO, increased renal blood flow (RBF, +38 ± 9% and reduced renal vascular resistance (RVR, -32 ± 6%. Glomerular filtration rate (GFR was not significantly altered but sodium excretion (UNa+V increased four-fold. After vehicle treatment, hypoxia (10% inspired O2 for 30 min did not significantly alter MAP or CO, but reduced HR (-17 ± 6%, increased RVR (+33 ± 16% and reduced GFR (-46 ± 16% and UNa+V (-41 ± 17%. Candesartan did not significantly alter these responses. After vehicle treatment, plasma volume expansion increased CO (+35 ± 7%, reduced total peripheral resistance (TPR, -26 ± 5%, increased RBF (+62 ± 23% and reduced RVR (-32 ± 9%, but did not significantly alter MAP or HR. It also increased UNa+V (803 ± 184% yet reduced GFR (-47 ± 9%. Candesartan did not significantly alter these responses. After vehicle treatment, mild hemorrhage did not significantly alter MAP but increased HR (+16 ± 3%, reduced CO (-16 ± 4% and RBF (-18 ± 6%, increased TPR (+18 ± 4% and tended to increase RVR (+18 ± 9%, P = 0.1, but had little effect on GFR or UNa+V. But after candesartan treatment MAP fell during hemorrhage (-19 ± 1%, while neither TPR nor RVR increased, and GFR (-64 ± 18% and UNa+V (-83 ± 10% fell. AT1-receptor activation supports MAP and GFR during hypovolemia. But AT1-receptors appear to play little role in the renal vasoconstriction, hypofiltration and antinatriuresis accompanying hypoxia, or the systemic and renal vasodilatation and natriuresis accompanying plasma volume expansion.

  11. Hemodynamic Changes After Static and Dynamic Exercises and Treadmill Stress Test; Different Patterns in Patients with Primary Benign Exertional Headache?

    Directory of Open Access Journals (Sweden)

    Mohsen Rostami

    2012-06-01

    Full Text Available The pathophysiology of primary benign exertional headache (EH is not still clearly defined. Some researchers have suggested an impaired vascular response as the etiology of this disorder. In this study we investigated whether there are any differences in blood pressure (BP and heart rate (HR of the subjects in course of the static and dynamic exercises and the treadmill stress test between those with and without EH. From university students, 22 patients with EH (mean age: 19.8 ± 2.10, Female to Male: 7:15 and 20 normal subjects (mean age: 19.3 ± 1.97, Female: Male: 8:12 were recruited. All the subjects performed the static and dynamic exercises at 30 and 20 percent of the maximal voluntary contraction (MVC and Bruce treadmill stress test according to the standard protocols. HR and BP of all the cases at the baseline and during and immediately after each test were measured. No significant difference was found between the mean rise of HR, systolic and diastolic BP of the subjects with and without EH in static and dynamic exercises and also treadmill stress test. It seems that between those with and without EH, there is no significant difference in rise of HR and BP response to static and dynamic exercises and treadmill stress test. Further studies are required to find the pathophysiology and risk factors of EH.

  12. Hemodynamic change in wall shear stress in patients with coronary bifurcation lesions treated by double kissing crush or single-stent technique.

    Science.gov (United States)

    Chen, Shao-Liang; Kan, Jing; Zhang, Jun-Jie; Hu, Zuo-Ying; Xu, Tian

    2012-05-01

    Fluid dynamic mechanisms attributed to coronary bifurcation lesions remain a subject of study. The present study aimed at investigating the hemodynamic change of wall shear stress (WSS) in patients with coronary bifurcation lesions treated by double kissing (DK) crush or one-stent with final kissing balloon inflation (FKBI). Eighty-one patients with bifurcation lesions treated by stenting who had 3-D model reconstruction were studied. The bifurcation vessels were divided into main vessel (MV), main branch (MB), side branch (SB), and polygon of confluence (POC). MB and SB were classified by internal- and lateral-subsegments, respectively. The baseline magnitude of WSS in proximal MV, POC-MV, POC-MB, POC-SB and MB-internal segments increased significantly, compared to MB-lateral, SB-internal and SB-lateral. DK crush had the potential of uniformly reducing WSS, turbulent index and the WSS gradient. The WSS value at the POC-SB and SB in the one-stent group remained higher. The turbulent index and WSS gradient between the POC-SB minus the SB-lateral had equal predictive values for in-stent restenosis (ISR). Fluid dynamic results favor the use of DK crush over the one-stent technique.

  13. Heart Rate Variability, Catecholamine and Hemodynamic Responses During Rest and Stress in Coronary Artery Disease Patients: The PIMI Study

    Science.gov (United States)

    2007-01-31

    system carries mostly vasoconstrictor fibers and only a few vasodilator fibers into the systemic vessels. Under normal conditions, all vessels are... vasoconstrictor nerves and excite the vagal innervations of the heart (Spallone & Menzinger, 1997). This, in return, causes vasodilation, and decrease in BP, HR...adaptation syndrome, and the role of stress and of the adaptive hormones in dental medicine. Oral Surg Oral Med Oral Pathol, 7(4), 355-367. Selye, H. (1975a

  14. Post-Treatment Hemodynamics of a Basilar Aneurysm and Bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J; Hartman, J; Rodriguez, J; Maitland, D

    2008-01-16

    Aneurysm re-growth and rupture can sometimes unexpectedly occur following treatment procedures that were initially considered to be successful at the time of treatment and post-operative angiography. In some cases, this can be attributed to surgical clip slippage or endovascular coil compaction. However, there are other cases in which the treatment devices function properly. In these instances, the subsequent complications are due to other factors, perhaps one of which is the post-treatment hemodynamic stress. To investigate whether or not a treatment procedure can subject the parent artery to harmful hemodynamic stresses, computational fluid dynamics simulations are performed on a patient-specific basilar aneurysm and bifurcation before and after a virtual endovascular treatment. The simulations demonstrate that the treatment procedure produces a substantial increase in the wall shear stress. Analysis of the post-treatment flow field indicates that the increase in wall shear stress is due to the impingement of the basilar artery flow upon the aneurysm filling material and to the close proximity of a vortex tube to the artery wall. Calculation of the time-averaged wall shear stress shows that there is a region of the artery exposed to a level of wall shear stress that can cause severe damage to endothelial cells. The results of this study demonstrate that it is possible for a treatment procedure, which successfully excludes the aneurysm from the vascular system and leaves no aneurysm neck remnant, to elevate the hemodynamic stresses to levels that are injurious to the immediately adjacent vessel wall.

  15. Computational fluid dynamics assisted characterization of parafoveal hemodynamics in normal and diabetic eyes using adaptive optics scanning laser ophthalmoscopy.

    Science.gov (United States)

    Lu, Yang; Bernabeu, Miguel O; Lammer, Jan; Cai, Charles C; Jones, Martin L; Franco, Claudio A; Aiello, Lloyd Paul; Sun, Jennifer K

    2016-12-01

    Diabetic retinopathy (DR) is the leading cause of visual loss in working-age adults worldwide. Previous studies have found hemodynamic changes in the diabetic eyes, which precede clinically evident pathological alterations of the retinal microvasculature. There is a pressing need for new methods to allow greater understanding of these early hemodynamic changes that occur in DR. In this study, we propose a noninvasive method for the assessment of hemodynamics around the fovea (a region of the eye of paramount importance for vision). The proposed methodology combines adaptive optics scanning laser ophthalmoscopy and computational fluid dynamics modeling. We compare results obtained with this technique with in vivo measurements of blood flow based on blood cell aggregation tracking. Our results suggest that parafoveal hemodynamics, such as capillary velocity, wall shear stress, and capillary perfusion pressure can be noninvasively and reliably characterized with this method in both healthy and diabetic retinopathy patients.

  16. Genome-Wide Linkage Analysis of Hemodynamic Parameters Under Mental and Physical Stress in Extended Omani Arab Pedigrees : The Oman Family Study

    NARCIS (Netherlands)

    Hassan, Mohammed O.; Jaju, Deepali; Voruganti, V. Saroja; Bayoumi, Riad A.; Albarwani, Sulayma; Al-Yahyaee, Saeed; Aslani, Afshin; Snieder, Harold; Lopez-Alvarenga, Juan C.; Al-Anqoudi, Zahir M.; Alizadeh, Behrooz Z.; Comuzzie, Anthony G.

    Background: We performed a genome-wide scan in a homogeneous Arab population to identify genomic regions linked to blood pressure (BP) and its intermediate phenotypes during mental and physical stress tests. Methods: The Oman Family Study subjects (N = 1277) were recruited from five extended

  17. Hemodynamic features and recurrence risk analysis of subtotally embolized ophthalmic aneurysms

    Directory of Open Access Journals (Sweden)

    Chuan-hui LI

    2011-12-01

    Full Text Available Objective The present study investigates the hemodynamic features in the residual necks of subtotally embolized ophthalmic aneurysms and their influence on the recurrence after operation.Methods Four ophthalmic aneurysm cases from January 2007 to July 2008 were studied.The aneurysms of the patients had residual necks after being embolized.Three-dimensional cerebral angiography images were taken before and after embolization,and the aneurysm modes were determined based on these images.The hemodynamic features in the residual neck before and after operation and during recurrence were analyzed by using a hydrodynamic software program and the finite-element method.Results The hemodynamic analysis shows that the residual neck had high shear stress and blood flow velocity regions after embolization in all four cases.Out of the four patients,three experienced recurrence,where blood flowed into the tumor cavity coinciding with the high shear stress regions.Conclusions High shear stress and blood flow velocity in the residual neck of embolized ophthalmic aneurysms manifested in the location of recurrence.Thus,hemodynamic factors may have an important role in the recurrence of ophthalmic aneurysms after embolization.

  18. Regional cerebral hemodynamics during re-build up phenomenon. Analysis by using {sup 99m}Tc-HMPAO SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kazumata, Ken; Kuroda, Satoshi; Houkin, Kiyohiro; Abe, Hiroshi [Hokkaido Univ., Sapporo (Japan). School of Medicine; Mitsumori, Kenji

    1994-12-01

    The re-build up phenomenon is the characteristic EEG finding following hyperventilation in childhood moyamoya disease. This study evaluated the role of cerebral blood flow (CBF) associated with this phenomenon using single photon emission CT (SPECT) with Tc-99m hexamethyl propylene amine oxime (Tc-99m HMPAO). The subjects were each two adult and pediatric patients. Tc-99m HMPAO (10 mCi) was injected immediately after 4-min hyperventilation. After the initial scanning, an additional 20 mCi of Tc-99m HMPAO was iv injected for the second scanning. Xe-133 SPECT was also performed for the evaluation of resting CBF. The re-build up phenomenon was observed preoperatively in one patient, which originated from the bilateral parieto-occipital area one min after hyperventilation and extended to the entire hemisphere 30 sec later. SPECT did not reveal severe ischemia in the entire hemisphere after hyperventilation, but revealed a marked CBF decrease in the bilateral parieto-occipital lobe. The patient underwent bilateral STA-MCA anastomosis combined with encephalo-duro-arterio-myo-synangiosis. Postoperative examination revealed no evidence of build-up phenomenon on EEG or abnormal perfusion reserve on Xe-133 SPECT. Nor was marked CBF decrease observed after hyperventilation on Tc-99m SPECT. These findings suggest that regional CBF decrease may play a critical role in the appearance of the re-build up phenomenon on EEG, as well as hypoxic hypoxia after hyperventilation. (N.K.).

  19. Region-specific vulnerability to endoplasmic reticulum stress ...

    Indian Academy of Sciences (India)

    2013-11-06

    Nov 6, 2013 ... Region-specific vulnerability to endoplasmic reticulum stress-induced neuronal death in rat brain after status epilepticus. JING CHEN. †,*. , HU GUO. †. , GUO ZHENG and ZHONG-NAN SHI. Department of Neurology, Nanjing Children's Hospital Affiliated to Nanjing Medical. University, No. 72, Guangzhou ...

  20. Time evolution and hemodynamics of cerebral aneurysms

    Science.gov (United States)

    Sforza, Daniel M.; Putman, Christopher; Tateshima, Satoshi; Viñuela, Fernando; Cebral, Juan

    2011-03-01

    Cerebral aneurysm rupture is a leading cause of hemorrhagic strokes. Because they are being more frequently diagnosed before rupture and the prognosis of subarachnoid hemorrhage is poor, clinicians are often required to judge which aneurysms are prone to progression and rupture. Unfortunately, the processes of aneurysm initiation, growth and rupture are not well understood. Multiple factors associated to these processes have been identified. Our goal is to investigate two of them, arterial hemodynamics (using computational fluid dynamics) and the peri-aneurysmal environment, by studying a group of growing cerebral aneurysms that are followed longitudinally in time. Six patients with unruptured untreated brain aneurysms which exhibited growth during the observation period were selected for the study. Vascular models of each aneurysm at each observation time were constructed from the corresponding computed tomography angiography (CTA) images. Subsequently, models were aligned, and geometrical differences quantified. Blood flow was modeled with the 3D unsteady incompressible Navier-Stokes equation for a Newtonian fluid, and wall shear stress distribution and flow patterns were calculated and visualized. Analysis of the simulations and changes in geometry revealed asymmetric growth patterns and suggests that areas subject to vigorous flows, i.e. relative high wall shear stress and concentrated streamlines patterns; correspond to regions of aneurysm growth. Furthermore, in some cases the geometrical evolution of aneurysms is clearly affected by contacts with bone structures and calcifications in the wall, and as a consequence the hemodynamics is greatly modified. Thus, in these cases the peri-aneurysmal environment must be considered when analyzing aneurysm evolution.

  1. Hemodynamic measurement using four-dimensional phase-contrast MRI: Quantification of hemodynamic parameters and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ho Jin; Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Guk Bae; Kweon, Ji Hoon; Kim, Young Hak; Lee, Deok Hee; Yang, Dong Hyun; KIm, Nam Kug [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-07-15

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  2. Hemodynamic Measurement Using Four-Dimensional Phase-Contrast MRI: Quantification of Hemodynamic Parameters and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Hojin [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Guk Bae [Asan Institute of Life Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kweon, Jihoon [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Young-Hak [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Deok Hee; Yang, Dong Hyun [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kim, Namkug [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of)

    2016-11-01

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  3. Nitric oxide transport in normal human thoracic aorta: effects of hemodynamics and nitric oxide scavengers.

    Directory of Open Access Journals (Sweden)

    Xiao Liu

    Full Text Available Despite the crucial role of nitric oxide (NO in the homeostasis of the vasculature, little quantitative information exists concerning NO transport and distribution in medium and large-sized arteries where atherosclerosis and aneurysm occur and hemodynamics is complex. We hypothesized that local hemodynamics in arteries may govern NO transport and affect the distribution of NO in the arteries, hence playing an important role in the localization of vascular diseases. To substantiate this hypothesis, we presented a lumen/wall model of the human aorta based on its MRI images to simulate the production, transport and consumption of NO in the arterial lumen and within the aortic wall. The results demonstrated that the distribution of NO in the aorta was quite uneven with remarkably reduced NO bioavailability in regions of disturbed flow, and local hemodynamics could affect NO distribution mainly via flow dependent NO production rate of endothelium. In addition, erythrocytes in the blood could moderately modulate NO concentration in the aorta, especially at the endothelial surface. However, the reaction of NO within the wall could only slightly affect NO concentration on the luminal surface, but strongly reduce NO concentration within the aortic wall. A strong positive correlation was revealed between wall shear stress and NO concentration, which was affected by local hemodynamics and NO reaction rate. In conclusion, the distribution of NO in the aorta may be determined by local hemodynamics and modulated differently by NO scavengers in the lumen and within the wall.

  4. Stressed Watersheds in a Rainfall-Rich Region

    Science.gov (United States)

    Kastrinos, J. R.; Miles, O.; Pickering, N. B.

    2016-12-01

    Southern New England has ample rainfall and, in some years, snowmelt, to sustain reservoirs and aquifers that are used primarily for municipal water supplies and secondarily for industrial and agricultural needs. Despite the humid climate, however, many watersheds are considered stressed, particularly during the summer and early fall growing-season months due to the combined effect of evapotranspiration and increased demand for lawn irrigation and other seasonal, warm-weather uses. While per capita consumption is frequently the focus of water-conservation efforts, most high-stress areas are in population centers where concentrated demand exceeds recharge (to aquifers) or runoff (to surface water supplies) within the region's small watersheds (commonly 200 mi2 or less). The parameter depletion intensity, described by Konikow (2015) in a review of groundwater-depletion trends across the United States, is used to compare seasonal stress and changes in stress level in several watersheds in Massachusetts. Areas of stress follow patterns of high depletion intensity during the summer months when demand is high. This seasonal stress is exacerbated by inter-basin transfer of water or wastewater from a watershed. Examples will be presented of projects where streamflow impacts have been offset using tools including well optimization, water conservation, storm water recharge, and reductions of infiltration/inflow to utilities, pursuant to the state's Sustainable Water Management Initiative.

  5. Untranslated regions (UTRs) orchestrate translation reprogramming in cellular stress responses.

    Science.gov (United States)

    Sajjanar, Basavaraj; Deb, Rajib; Raina, Susheel Kumar; Pawar, Sachin; Brahmane, Manoj P; Nirmale, Avinash V; Kurade, Nitin P; Manjunathareddy, Gundallahalli B; Bal, Santanu Kumar; Singh, Narendra Pratap

    2017-04-01

    Stress is the result of an organism's interaction with environmental challenges. Regulations of gene expression including translation modulations are critical for adaptation and survival under stress. Untranslated regions (UTRs) of the transcripts play significant roles in translation regulation and continue to raise many intriguing questions in our understanding of cellular stress physiology. IRES (Internal ribosome entry site) and uORF (upstream open reading frame) mediated alternative translation initiations are emerging as unique mechanisms. Recent studies have revealed novel means of mRNAs stabilization in stress granules and their reversible modifications. Differential regulation of select transcripts is possible by the interplay between the adenine/uridine-rich elements (AREs) in 3'UTR with their binding proteins (AUBP) and by microRNA-mediated effects. Coordination of these various mechanisms control translation and thereby enables appropriate responses to environmental stress. In this review, we focus on the role of sequence signatures both at 5' and 3'UTRs in translation reprogramming during cellular stress responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. [Stress reduction through listening to music: effects on stress hormones, hemodynamics and mental state in patients with arterial hypertension and in healthy persons].

    Science.gov (United States)

    Möckel, M; Störk, T; Vollert, J; Röcker, L; Danne, O; Hochrein, H; Eichstädt, H; Frei, U

    1995-05-26

    Stress hormones, tissue-plasminogen activator (t-PA) antigen, left-ventricular diastolic function and mood immediately before and after listening to three different kinds of music (a waltz by J. Strauss, a piece of modern classic by H. W. Henze, and meditative music by R. Shankar) were measured in 20 healthy persons (10 women, 10 men; mean age 25 [20-33] years) and 20 hypertensives (8 women, 12 men; mean age 57.5 [25-72] years). To recognise haemodynamic effects, mitral flow by Doppler ultrasound was used as a measure of left-ventricular diastolic function. Atrial filling pressure (AFF) was calculated from the flow integral (VTI) of the early E and the late A waves. The Zerssen scale was used to estimate the immediate mood of the subjects. In hypertensives the levels of cortisol (74 vs 78 ng/ml; P music, VTI-E fell (69 vs 73 mm; P < 0.05, while natriuretic peptide rose (63 vs 60 pg/ml; P < 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Numerical modeling of regional stress distributions for geothermal exploration

    Science.gov (United States)

    Guillon, Theophile; Peter-Borie, Mariane; Gentier, Sylvie; Blaisonneau, Arnold

    2017-04-01

    Any high-enthalpy unconventional geothermal projectcan be jeopardized by the uncertainty on the presence of the geothermal resource at depth. Indeed, for the majority of such projects the geothermal resource is deeply seated and, with the drilling costs increasing accordingly, must be located as precisely as possible to increase the chance of their economic viability. In order to reduce the "geological risk", i.e., the chance to poorly locate the geothermal resource, a maximum amount of information must be gathered prior to any drilling of exploration and/or operational well. Cross-interpretation from multiple disciplines (e.g., geophysics, hydrology, geomechanics …) should improve locating the geothermal resource and so the position of exploration wells ; this is the objective of the European project IMAGE (grant agreement No. 608553), under which the work presented here was carried out. As far as geomechanics is concerned, in situ stresses can have a great impact on the presence of a geothermal resource since they condition both the regime within the rock mass, and the state of the major fault zones (and hence, the possible flow paths). In this work, we propose a geomechanical model to assess the stress distribution at the regional scale (characteristic length of 100 kilometers). Since they have a substantial impact on the stress distributions and on the possible creation of regional flow paths, the major fault zones are explicitly taken into account. The Distinct Element Method is used, where the medium is modeled as fully deformable blocks representing the rock mass interacting through mechanically active joints depicting the fault zones. The first step of the study is to build the model geometry based on geological and geophysical evidences. Geophysical and structural geology results help positioning the major fault zones in the first place. Then, outcrop observations, structural models and site-specific geological knowledge give information on the fault

  8. Complex regional pain syndrome as a stress response.

    Science.gov (United States)

    Grande, Lucinda A; Loeser, John D; Ozuna, Judy; Ashleigh, Alexandra; Samii, Ali

    2004-07-01

    A man in his 50's with a prior traumatic brain injury and multiple psychiatric disorders developed acute pain and swelling in his left leg distal to the mid shin. These symptoms arose during an exacerbation of his post-traumatic stress disorder (PTSD). Among his traumatic memories, he reported having witnessed the combat injury and death of a friend who had lost his left leg distal to the mid shin. A diagnosis of conversion disorder was technically excluded because the findings met criteria for Complex Regional Pain Syndrome (CRPS) type I. Based on recent research into the neurobiology of CRPS, PTSD and conversion disorder, we propose a supraspinal mechanism which could explain how emotional stress can produce both symptoms and signs.

  9. Computational study of anterior communicating artery hemodynamics before aneurysm formation

    Science.gov (United States)

    Castro, Marcelo A.; Putman, Christopher M.; Cebral, Juan R.

    2012-03-01

    It is widely accepted that complexity in the flow pattern at the anterior communicating artery (AComA) is associated with the high rate of aneurysm formation in that location observed in large studies. A previous computational hemodynamic study showed a possible association between high maximum intraaneurysmal wall shear stress (WSS) at the systolic peak with rupture in a cohort of AComA aneurysms. In another study it was observed a connection between location of aneurysm blebs and regions of high WSS in models where blebs were virtually removed. However, others reported associations between low WSS and either rupture or blister formation. The purpose of this work is to study associations between hemodynamic patterns and AComA aneurysm initiation by comparing hemodynamics in the aneurysm and the normal model where the aneurysm was computationally removed. Vascular models of both right and left circulation were independently reconstructed from three-dimensional rotational angiography images using deformable models, and fused using a surface merging algorithm. The geometric models were then used to generate high-quality volumetric finite element grids of tetrahedra with an advancing front technique. For each patient, the second anatomical model was created by digitally removing the aneurysm. It was iteratively achieved by applying a Laplacian smoothing filter and remeshing the surface. Finite element blood flow numerical simulations were performed. It was observed that aneurysms initiated in regions of high and moderate WSS in the counterpart normal models. Adjacent or close to those regions, low WSS portions of the arterial wall were not affected by the disease.

  10. Hemodynamic Support in Sepsis

    Directory of Open Access Journals (Sweden)

    Fatih Yildiz

    2014-04-01

    Full Text Available Sepsis is called systemic inflammatory response syndrome due to infection. When added to organs failure and perfusion abnormality is defined in severe sepsis, Hypotension that do not respond to fluid therapy is as defined septic shock. Fluid resuscitation is a most important parts of the treatment in patients with septic shock. Ongoing hypotension that despite of the adequate fluid therapy, vasopressor support initiation is required. Sepsis and septic shock, hemodynamic support is often understood as the hemodynamic support. The different approaches to the development of methods to track and objective comes up. Patients with severe sepsis and septic shock should be follow in the intensive care unit and rapid fluid replacement and effectual hemodynamic support should be provided.

  11. Regional Stress Field in the Maghreb Region From an Updated Focal Mechanism Catalog (1954-2014)

    Science.gov (United States)

    Lamara, Samir; Friederich, Wolfgang

    2015-04-01

    In order to investigate the regional stress field in the Maghreb region we construct a focal mechanism catalog for earthquakes that occurred from 1954 to 2014. To this intent, all available moment tensor solutions of past earthquakes obtained from different sources were checked, compared and corrected. Furthermore, the focal solutions of all recent earthquakes with magnitude down to 4 and for which data is available were calculated using a new method based on waveform fitting of observed seismograms and synthetics calculated for a range of fault angles and hypocenter depths. Observed seismograms of all stations for a given earthquake were thus collected, processed and subject to a rigorous quality control according to the corresponding signal-to-noise ratio. An average 1-D earth model for the Maghreb-western Mediterranean region was also constructed to calculate synthetics. The misfits between these observed seismograms and a set of synthetics calculated for every value of fault angles (strike, dip and rake) and hypocenter depths were calculated after respectively, a phase fitting obtained by shifting the seismograms to the best cross-correlation between data and synthetics, and amplitudes scaling. The best configuration of fault angles and hypocenter depths was then selected according to the smallest average misfit over all stations. If a systematic time shift was noticeable for all stations or most of them, an additional relocation step was done to obtain the most accurate earthquake's epicenter. Most of the earthquakes included in the catalog define several spatial clusters for which the assumption of homogeneous stress can be fulfilled. Hence, a stress inversion for each cluster was performed and a stress ratio indicating the dominance of compressional or tensional stresses as well as the directions and dips of the tensional, intermediate and compressional axis were obtained.

  12. Hemodynamics of Cerebral Aneurysms

    Science.gov (United States)

    Sforza, Daniel M.; Putman, Christopher M.; Cebral, Juan Raul

    2009-01-01

    The initiation and progression of cerebral aneurysms are degenerative processes of the arterial wall driven by a complex interaction of biological and hemodynamic factors. Endothelial cells on the artery wall respond physiologically to blood-flow patterns. In normal conditions, these responses are associated with nonpathological tissue remodeling and adaptation. The combination of abnormal blood patterns and genetics predisposition could lead to the pathological formation of aneurysms. Here, we review recent progress on the basic mechanisms of aneurysm formation and evolution, with a focus on the role of hemodynamic patterns.

  13. Hemodynamic Profiling in Complicated Pregnancies

    NARCIS (Netherlands)

    J.M.J. Cornette (Jérôme)

    2016-01-01

    textabstractIn order to permit a successful pregnancy outcome, the cardiovascular system must undergo substantial changes. This thesis addresses the hemodynamics in several pregnancy complications. A general overview of normal hemodynamic adaptation to pregnancy is provided . Several techniques of

  14. Obesity and renal hemodynamics

    NARCIS (Netherlands)

    Bosma, R. J.; Krikken, J. A.; van der Heide, J. J. Homan; de Jong, P. E.; Navis, G. J.

    2006-01-01

    Obesity is a risk factor for renal damage in native kidney disease and in renal transplant recipients. Obesity is associated with several renal risk factors such as hypertension and diabetes that may convey renal risk, but obesity is also associated with an unfavorable renal hemodynamic profile

  15. Physiology of hemodynamic homeostasis

    NARCIS (Netherlands)

    de Hert, Stefan

    2012-01-01

    Homeostasis of hemodynamics refers to the regulation of the blood circulation to meet the demands of the different organ and tissue systems. This homeostasis involves an intimate interaction between peripheral metabolic needs, vascular adaptations to meet these needs and cardiac adaptation to

  16. Hemodynamic simulations in coronary aneurysms of children with Kawasaki disease

    Science.gov (United States)

    Sengupta, Dibyendu; Burns, Jane; Marsden, Alison

    2009-11-01

    Kawasaki disease (KD) is a serious pediatric illness affecting the cardiovascular system. One of the most serious complications of KD, occurring in about 25% of untreated cases, is the formation of large aneurysms in the coronary arteries, which put patients at risk for myocardial infarction. In this project we performed patient specific computational simulations of blood flow in aneurysmal left and right coronary arteries of a KD patient to gain an understanding about their hemodynamics. Models were constructed from CT data using custom software. Typical pulsatile flow waveforms were applied at the model inlets, while resistance and RCR lumped models were applied and compared at the outlets. Simulated pressure waveforms compared well with typical physiologic data. High wall shear stress values are found in the narrow region at the base of the aneurysm and low shear values occur in regions of recirculation. A Lagrangian approach has been adopted to perform particle tracking and compute particle residence time in the recirculation. Our long-term goal will be to develop links between hemodynamics and the risk for thrombus formation in order to assist in clinical decision-making.

  17. Exercise hemodynamics in patients with and without diastolic dysfunction and preserved ejection fraction after myocardial infarction

    DEFF Research Database (Denmark)

    Andersen, Mads J; Ersbøll, Mads; Bro-Jeppesen, John

    2012-01-01

    Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress.......Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress....

  18. New method for retrospective study of hemodynamic changes before and after aneurysm formation in patients with ruptured or unruptured aneurysms

    Science.gov (United States)

    2013-01-01

    Background Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult. We used a vessel surface repair method to carry out a retrospective hemodynamic study before and after aneurysm formation in a ruptured aneurysm of the posterior communicating artery (RPcomAA) and an unruptured aneurysm of the posterior communicating artery (URPcomAA). Methods Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling. Hemodynamic parameters such as wall shear stress (WSS), blood-flow velocity, streamlines, pressure, and wall shear stress gradient (WSSG) in the aneurysm sac and at the site of aneurysm formation were analyzed in each model. Results At “aneurysm” status, hemodynamic analyses at the neck, body, and dome of the aneurysm revealed the distal aneurysm neck to be subjected to the highest WSS and blood-flow velocity, whereas the aneurysm dome presented the lowest WSS and blood-flow velocity in both model types. More apparent changes in WSSG at the aneurysm dome with an inflow jet and narrowed impaction zone were revealed only in the RPcomAA. At “pre-aneurysm” status, hemodynamic analyses in both models showed that the region of aneurysm formation was subjected to extremely elevated WSS, WSSG, and blood-flow velocity. Conclusions These data suggest that hemodynamic analyses in patients with ruptured or unruptured aneurysms using the vessel surface repair method are feasible, economical, and simple. Our preliminary results indicated that the arterial wall was subjected to elevated WSS, WSSG and blood-flow velocity before aneurysm generation. However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm. PMID:24195732

  19. Individual and regional association between socioeconomic status and uncertainty stress, and life stress: a representative nationwide study of China.

    Science.gov (United States)

    Yang, Tingzhong; Yang, Xiaozhao Y; Yu, Lingwei; Cottrell, Randall R; Jiang, Shuhan

    2017-07-05

    Many studies have examined the association between socioeconomic status (SES) and mental stress. Uncertainty stress is a prominent aspect of mental stress. Yet no research has ever empirically analyzed the impact of SES on uncertainty stress. Students were identified through a multistage survey sampling process including 50 universities. Each student participant completed the Global Health Professions Student Survey (GHPSS) on Tobacco Control in China. Regional variables were retrieved from the National Bureau of Statistics database. Both unadjusted and adjusted methods were considered in the analyses. Among the 11,942 participants, severe uncertainty stress prevalence was 19.6%, while severe life stress prevalence was 8.6%. Multilevel logistic regression showed that most SES variables were associated with uncertainty stress. Students with "operation and commercial work" as mother's occupation and "rural or township" as family location exhibited a higher prevalence of severe uncertainty stress. Lower family income and original region gross domestic products (GDP) were also associated with higher severe uncertainty stress prevalence. However, only father's occupation was correlated with life stress. Based on the literature review, this is the first empirical study examining the impact of SES on uncertainty stress in China and elsewhere in the world. Our research underscores the importance of decreasing socioeconomic inequalities in controlling excessive uncertainty stress.

  20. Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

    Directory of Open Access Journals (Sweden)

    Venkat Keshav Chivukula

    2015-12-01

    Full Text Available We analyzed heart wall motion and blood flow dynamics in chicken embryos using in vivo optical coherence tomography (OCT imaging and computational fluid dynamics (CFD embryo-specific modeling. We focused on the heart outflow tract (OFT region of day 3 embryos, and compared normal (control conditions to conditions after performing an OFT banding intervention, which alters hemodynamics in the embryonic heart and vasculature. We found that hemodynamics and cardiac wall motion in the OFT are affected by banding in ways that might not be intuitive a priori. In addition to the expected increase in ventricular blood pressure, and increase blood flow velocity and, thus, wall shear stress (WSS at the band site, the characteristic peristaltic-like motion of the OFT was altered, further affecting flow and WSS. Myocardial contractility, however, was affected only close to the band site due to the physical restriction on wall motion imposed by the band. WSS were heterogeneously distributed in both normal and banded OFTs. Our results show how banding affects cardiac mechanics and can lead, in the future, to a better understanding of mechanisms by which altered blood flow conditions affect cardiac development leading to congenital heart disease.

  1. Safety, hemodynamic profile, and feasibility of dobutamine stress technetium myocardial perfusion single-photon emission CT imaging for evaluation of coronary artery disease in the elderly

    NARCIS (Netherlands)

    A. Elhendy (Abdou); J.J. Bax (Jeroen); R. Valkema (Roelf); A.E.M. Reijs (Ambroos); E.P. Krenning (Eric); J.R.T.C. Roelandt (Jos); R.T. van Domburg (Ron)

    2000-01-01

    textabstractOBJECTIVES: Cardiovascular disease is the leading cause of morbidity and mortality in the elderly. The evaluation of coronary artery disease by exercise stress testing is frequently limited by the patient's inability to exercise. Although pharmacologic

  2. High WSS or low WSS? Complex interactions of hemodynamics with intracranial aneurysm initiation, growth, and rupture: toward a unifying hypothesis

    National Research Council Canada - National Science Library

    Meng, H; Tutino, V M; Xiang, J; Siddiqui, A

    2014-01-01

    ... of aneurysm rupture risk. Image-based computational fluid dynamics models have suggested associations between hemodynamics and intracranial aneurysm rupture, albeit with conflicting findings regarding wall shear stress...

  3. Competence in Coping with Stress in Adolescents from Three Regions of the World

    Science.gov (United States)

    Persike, Malte; Seiffge-Krenke, Inge

    2012-01-01

    The ways adolescents develop and use strategies to cope with stress vary according to cultural scripts and values. This cross-sectional study tested the impact of region and gender on adolescents' stress perceptions and coping styles. A total sample of 10,941 adolescents (51.3% female) from 20 countries completed questionnaires on stress and…

  4. Hemodynamics Modeling and Simulation of Anterior Communicating Artery Aneurysms

    Directory of Open Access Journals (Sweden)

    Jianjun Li

    2014-07-01

    Full Text Available It is a general agreement that hemodynamics plays very important role in the initiation, growth, and rupture of cerebral aneurysms and hemodynamics in the anterior communicating artery aneurysms is considered the most complex in all cerebral aneurysms and it is difficult to find some reasonable relationship between the hemodynamics parameters and the rupture risk. In this paper, the 3D geometries of four anterior communicating artery aneurysms were generated from the CTA data and the computational models with bilateral feeding arteries for the four aneurysms were constructed. The blood flow was simulated by computational fluid dynamics software and the hemodynamics parameters such as velocity, wall shear stress, and oscillatory shear index were calculated. The following results were observed: one of the four models only needs the left feeding artery; the max normalized wall shear stress locates at the aneurysmal neck of the largest aneurysm; the max oscillatory shear index locates at the aneurysmal sac of the largest aneurysm. The conclusion was drawn that the anterior communicating artery aneurysm has higher rupture risk from the hemodynamics viewpoint if the max wall shear stress locates at the neck and the max oscillatory shear index locates at the dome.

  5. Adapting to Water Stress in the Comahue Region of Argentina ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    , quality, and distribution -generate local and regional climate and hydrological models and scenarios for mid- and long-term water availability -assess current water availability, use, and distribution in sub-regions of the Comahue and provide ...

  6. Hemodynamic analysis of a novel bioresorbable scaffold in porcine coronary artery model

    NARCIS (Netherlands)

    Tenekecioglu, Erhan; Torii, Ryo; Bourantas, Christos V.; Cavalcante, Rafael; Sotomi, Yohei; Zeng, Yaping; Collet, Carlos; Crake, Tom; Abizaid, Alexandre; Onuma, Yoshinobu; Su, Solomon; Santoso, Teguh; Serruys, Patrick W.

    2017-01-01

    The shear stress distribution assessment can provide useful insights for the hemodynamic performance of the implanted stent/scaffold. Our aim was to investigate the effect of a novel bioresorbable scaffold, Mirage on local hemodynamics in animal models. The main epicardial coronary arteries of 7

  7. [Results of Regional Project 'Work related Stress' 2004-2006].

    Science.gov (United States)

    Latocca, R; Fornari, C; Madotto, F; Cesana, G C

    2009-01-01

    The present epidemiological study aimed to investigate prevalence and trends of stress-job-related uneasiness and symptoms on a representative sample of Lombardia's working population. Data on occupational events (absenteeism and accidents at work), psychosomatic symptoms and smoke habit have been collected. Prevalence and trends of stress-job-related uneasiness are similar to those reported by the European Foundation in the Report for Sectorial Profiles (2002). The study confirms higher levels of absenteeism in corporations with high prevalence of women and in low socioeconomic level works.

  8. Hemodynamic Based Coronary Artery Aneurysm Thrombosis Risk Stratification in Kawasaki Disease Patients

    Science.gov (United States)

    Grande Gutierrez, Noelia; Mathew, M.; McCrindle, B.; Kahn, A.; Burns, J.; Marsden, A.

    2017-11-01

    Coronary artery aneurysms (CAA) as a result of Kawasaki Disease (KD) put patients at risk for thrombosis and myocardial infarction. Current AHA guidelines recommend CAA diameter >8 mm or Z-score >10 as the criterion for initiating systemic anticoagulation. Our hypothesis is that hemodynamic data derived from computational blood flow simulations is a better predictor of thrombosis than aneurysm diameter alone. Patient-specific coronary models were constructed from CMRI for a cohort of 10 KD patients (5 confirmed thrombosis cases) and simulations with fluid structure interaction were performed using the stabilized finite element Navier-Stokes solver available in SimVascular. We used a closed-loop lumped parameter network (LPN) to model the heart and vascular boundary conditions coupled numerically to the flow solver. An automated parameter estimation method was used to match LPN values to clinical data for each patient. Hemodynamic data analysis resulted in low correlation between Wall Shear Stress (WSS)/ Particle Residence Time (PRT) and CAA diameter but demonstrates the positive correlation between hemodynamics and adverse patient outcomes. Our results suggest that quantifying WSS and PRT should enable identification of regions at higher risk of thrombosis. We propose a quantitative method to non-invasively assess the abnormal flow in CAA following KD that could potentially improve clinical decision-making regarding anticoagulation therapy.

  9. Hemodynamic simulations in coronary aneurysms of a patient with Kawasaki Disease

    Science.gov (United States)

    Sengupta, Dibyendu; Marsden, Alison; Burns, Jane

    2010-11-01

    Kawasaki Disease is the leading cause of acquired pediatric heart disease, and can cause large coronary artery aneurysms in untreated cases. A simulation case study has been performed for a 10-year-old male patient with coronary aneurysms. Specialized coronary boundary conditions along with a lumped parameter heart model mimic the interactions between the ventricles and the coronary arteries, achieving physiologic pressure and flow waveforms. Results show persistent low shear stress in the aneurismal regions, and abnormally high shear at the aneurysm neck. Correlation functions have been derived to compare wall shear stress and wall shear stress gradients with recirculation time with the idea of localizing zones of calcification and thrombosis. Results are compared with those of an artificially created normal coronary geometry for the same patient. The long-term goal of this work is to develop links between hemodynamics and thrombotic risk to assist in clinical decision-making.

  10. Stress relaxation in the region of microplastic deformation of polycrystals

    Science.gov (United States)

    Pochivalova, G. P.; Dudarev, E. F.; Nikitina, N. V.

    1987-07-01

    Stress relaxation equations are derived to predict the relaxation capacity of a material on the basis of studies of microplastic deformation under static loading. The approach was checked experimentally on spring steels LANKMts, ÉI702, ÉP637, and 50KhFA.

  11. Ex-vivo diffusion MRI reveals microstructural alterations in stress-sensitive brain regions: A chronic mild stress recovery study

    DEFF Research Database (Denmark)

    Khan, Ahmad Raza; Hansen, Brian; Wiborg, Ove

    Depression is a leading cause of disability worldwide and causes significant microstructural alterations in stress-sensitive brain regions. However, the potential recovery of these microstructural alterations has not previously been investigated, which we, therefore, set out to do using diffusion...... MRI (d-MRI) in the chronic mild stress (CMS) rat model of depression. This study reveals significant microstructural alterations after 8 weeks of recovery, in the opposite direction to change induced by stress in the acute phase of the experiment. Such findings may be useful in the prognosis...

  12. Region-specific vulnerability to endoplasmic reticulum stress ...

    Indian Academy of Sciences (India)

    The expression of GRP78 protein was increased at 3, 6 and 12 h after SE and no brain region variability was found. The expression of CHOP protein was also increased, reached its peak at 24 h and remained high at 48 h. CHOP protein expression, however, showed brain region variability with highest expression noted in ...

  13. Adapting to Water Stress in the Comahue Region of Argentina ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Climate change is expected to lead to decreases in annual precipitation for the Comahue region in central-west Argentina. Combined with a projected increase in water demand and use, this will likely result in more frequent and severe water shortages over the coming decades. Water access and distribution in the region is ...

  14. Stressful life events and psychological dysfunction in complex regional pain syndrome type I

    NARCIS (Netherlands)

    Geertzen, JHB; de Bruijn-Kofman, AT; de Bruijn, HP; van de Wiel, HBM; Dijkstra, PU

    Objective: To determine to what extent stressful life events and psychological dysfunction play a role in the pathogenesis of Complex Regional Pain Syndrome type I (CRPS). Design: A comparative study between a CRPS group and a control group. Stressful life events and psychological dysfunction

  15. Clonidine decreases stress response in patients undergoing carotid endarterectomy under regional anesthesia: a prospective, randomized, double-blinded, placebo-controlled study.

    Science.gov (United States)

    Schneemilch, Christine E; Bachmann, Holger; Ulrich, Anke; Elwert, Regine; Halloul, Zuhir; Hachenberg, Thomas

    2006-08-01

    Inadequate analgesia or anxiety may induce an increased stress response in patients undergoing carotid endarterectomy (CEA) under regional anesthesia (RA). Central alpha2 adrenoceptor agonists have significant sedative and analgesic properties, which may attenuate sympathoadrenal activation during CEA and improve the quality of RA. We randomly assigned 80 patients to 2 groups receiving either RA plus placebo (n = 40) or RA plus clonidine 1 microg/kg as the initial loading dose followed by 1 microg.kg(-1).h(-1) (n = 40). RA was performed as combined deep and superficial cervical plexus blockade. Hemodynamic and neurological variables were assessed before, during, and after CEA. Arterial blood samples were collected at defined time points for the determination of plasma concentrations of epinephrine, norepinephrine, cortisol, and creatinine kinase and creatinine kinase-MB. Throughout the study, all patients responded easily to neurological evaluations. Before and during clamping mean arterial blood pressure and heart rate were not different between the groups, but mean arterial blood pressure was lower in the clonidine group (P < 0.01) at skin closure and postoperatively in the intensive care unit. In the placebo group, cortisol, epinephrine, and norepinephrine plasma concentrations were increased significantly (P < 0.05) and more patients required antihypertensive treatment (P < 0.01). Postoperatively the incidence of hypertension (P < 0.001) and development of neurological deficits (P < 0.05) was significantly decreased in the clonidine group. We conclude that 1 microg.kg(-1).h(-1) clonidine suppresses the hyperadrenergic response to CEA without adverse effects on hemodynamics or clinical neurological monitoring.

  16. Stress-induced decreases in local cerebral glucose utilization in specific regions of the mouse brain

    Directory of Open Access Journals (Sweden)

    Warnock Geoff I

    2011-03-01

    Full Text Available Abstract Background Restraint stress in rodents has been reported to activate the hypothalamic-pituitary-adrenocortical (HPA axis and to increase c-fos expression in regions that express components of the corticotropin-releasing factor (CRF system. We have previously reported that acute central administration of CRF increased a measure of relative local cerebral glucose utilization (LCGU, a measure of neuronal activity in specific brain regions, and activated the HPA axis in mice. It was hypothesized that the involvement of the CRF system in the stress response would lead to similar changes in relative LCGU after restraint stress. In the present studies the effect of restraint stress on relative LCGU and on the HPA axis in C57BL/6N mice were examined. Findings Restraint stress activated the HPA axis in a restraint-duration dependent manner, but in contrast to the reported effects of CRF, significantly decreased relative LCGU in frontal cortical, thalamic, hippocampal and temporal dissected regions. These findings support evidence that stressors enforcing limited physical activity reduce relative LCGU, in contrast to high activity stressors such as swim stress. Conclusions In conclusion, the present studies do not support the hypothesis that stress-induced changes in relative LCGU are largely mediated by the CRF system. Further studies will help to delineate the role of the CRF system in the early phases of the relative LCGU response to stress and investigate the role of other neurotransmitter systems in this response.

  17. Stress-induced decreases in local cerebral glucose utilization in specific regions of the mouse brain.

    Science.gov (United States)

    Warnock, Geoff I; Steckler, Thomas

    2011-03-31

    Restraint stress in rodents has been reported to activate the hypothalamic-pituitary-adrenocortical (HPA) axis and to increase c-fos expression in regions that express components of the corticotropin-releasing factor (CRF) system. We have previously reported that acute central administration of CRF increased a measure of relative local cerebral glucose utilization (LCGU), a measure of neuronal activity in specific brain regions, and activated the HPA axis in mice. It was hypothesized that the involvement of the CRF system in the stress response would lead to similar changes in relative LCGU after restraint stress. In the present studies the effect of restraint stress on relative LCGU and on the HPA axis in C57BL/6N mice were examined. Restraint stress activated the HPA axis in a restraint-duration dependent manner, but in contrast to the reported effects of CRF, significantly decreased relative LCGU in frontal cortical, thalamic, hippocampal and temporal dissected regions. These findings support evidence that stressors enforcing limited physical activity reduce relative LCGU, in contrast to high activity stressors such as swim stress. In conclusion, the present studies do not support the hypothesis that stress-induced changes in relative LCGU are largely mediated by the CRF system. Further studies will help to delineate the role of the CRF system in the early phases of the relative LCGU response to stress and investigate the role of other neurotransmitter systems in this response.

  18. Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

    Science.gov (United States)

    Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Cowan, Brett

    2016-02-01

    Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

  19. The stress field of Vrancea region from fault plane solution (FPS

    Directory of Open Access Journals (Sweden)

    L. Telesca

    2011-10-01

    Full Text Available The fault plane solutions (FPS of 247 seismic events were used for stress field investigation of the region. The eigenvectors t, p, b, and moment tensor M components for each FPS were defined and computed numerically. The obtained results confirm the hypothesis of subduction-type intermediate depth earthquakes for the Vrancea seismic region and this may be considered the first approximation of the stress field for the whole of the Vrancea (intermediate depth region.

  20. A geometric scaling model for assessing the impact of aneurysm size ratio on hemodynamic characteristics

    Science.gov (United States)

    2014-01-01

    Background The intracranial aneurysm (IA) size has been proved to have impacts on the hemodynamics and can be applied for the prediction of IA rupture risk. Although the relationship between aspect ratio and hemodynamic parameters was investigated using real patients and virtual models, few studies focused on longitudinal experiments of IAs based on patient-specific aneurysm models. We attempted to do longitudinal simulation experiments of IAs by developing a series of scaled models. Methods In this work, a novel scaling approach was proposed to create IA models with different aneurysm size ratios (ASRs) defined as IA height divided by average neck diameter from a patient-specific aneurysm model and the relationship between the ASR and hemodynamics was explored based on a simulated longitudinal experiment. Wall shear stress, flow patterns and vessel wall displacement were computed from these models. Pearson correlation analysis was performed to elucidate the relationship between the ASR and wall shear stress. The correlation of the ASR and flow velocity was also computed and analyzed. Results The experiment results showed that there was a significant increase in IA area exposed to low WSS once the ASR > 0.7, and the flow became slower and the blood was more difficult to flow into the aneurysm as the ASR increased. Meanwhile, the results also indicated that average blood flow velocity and WSS had strongly negative correlations with the ASR (r = −0.938 and −0.925, respectively). A narrower impingement region and a more concentrated inflow jet appeared as the ASR increased, and the large local deformation at aneurysm apex could be found as the ASR >1.7 or 0.7 aneurysm scaled models applying our proposed IA scaling algorithm. PMID:24528952

  1. Evaluation of cerebral metabolism in patients with unilateral carotid stenosis by proton MR spectroscopy: a correlative study with cerebral hemodynamics by acetazolamide stress brain perfusion SPECT (acz-SPECT)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung; Kim, Geun Eun; Lee, Jeong Hee; Kim, Do Gyun; Kim, Sang Tae; Lee, Hee Kyung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2001-07-01

    Carotid stenosis may lead not only to cerebral hemodynamic compromise but also cerebral metabolic changes without overt infarction. To investigate the brain metabolic changes as a result of hemodynamic compromise in pts with carotid stenosis, we compared the changes in metabolism of the gray and white matter detected by proton MRS with cortical hemodynamics measured by Acz-SPECT. We prospectively studied symptomatic 18 pts (M/F=15/3, mean ages: 64.4y) with unilateral carotid stenosis. All pts underwent Acz-SPECT and MRS with 3 days. rCBF and rCVR of MCA territory were assessed by Acz-SPECT. Hemodynamic compromise was graded as stage 0 (normal rCBF and rCVR), stage 1 (normal rCBF and reduced rCVR), and stage 2( reduced rCBF and rCVR). Brain metabolism was assessed by measuring the peaks of N-acetyl aspartate (NAA), choline (Cho), and the sum of creatine and phosphocreatine (Cr) from noninfarcted white matter in the both centrum semiovales and gray matter in both MCA territories. On Acz-SPECT, 7 pts showed stage 2 were significantly lower than in pts with stage 0 (p<0.01). The asymmetric ratio of NAA/Cr in pts with state 2 was also significantly lower than in pts with stage 1(p<0.05). The asymmetric ratio of Cho/Cr was increased as hemodynamic stage increased but the differences were not statistically significant among 3 stages. In cortical gray matter, the asymmetric ratios of NAA/Cho and NAA/Cr were decreased statistically significant among 3 stages. In cortical gray matter, the asymmetric ratios of NAA/Cho and NAA/Cr were decreased and that of Cho/Cr was increased as hemodynamic stage increased. However, these differences were not statistically significant among 3 stages. The asymmetric ratios of NAA/Cho of centrum semiovale in pts with reduced rCBF and/or reduced rCVR were lower than in pts with normal perfusion. Our results indicate the metabolic changes detected by proton MRS in patients with carotid stenosis reflect a hemodynamic compromised state.

  2. Novel approaches to alcohol rehabilitation: Modification of stress-responsive brain regions through environmental enrichment.

    Science.gov (United States)

    Pang, Terence Y; Hannan, Anthony J; Lawrence, Andrew J

    2018-02-22

    Relapse remains the most prominent hurdle to successful rehabilitation from alcoholism. The neural mechanisms underlying relapse are complex, but our understanding of the brain regions involved, the anatomical circuitry and the modulation of specific nuclei in the context of stress and cue-induced relapse have improved significantly in recent years. In particular, stress is now recognised as a significant trigger for relapse, adding to the well-established impact of chronic stress to escalate alcohol consumption. It is therefore unsurprising that the stress-responsive regions of the brain have also been implicated in alcohol relapse, such as the nucleus accumbens, amygdala and the hypothalamus. Environmental enrichment is a robust experimental paradigm which provides a non-pharmacological tool to alter stress response and, separately, alcohol-seeking behaviour and symptoms of withdrawal. In this review, we examine and consolidate the preclinical evidence that alcohol seeking behaviour and stress-induced relapse are modulated by environmental enrichment, and these are primarily mediated by modification of neural activity within the key nodes of the addiction circuitry. Finally, we discuss the limited clinical evidence that stress-reducing approaches such as mindfulness could potentially serve as adjunctive therapy in the treatment of alcoholism. Copyright © 2018. Published by Elsevier Ltd.

  3. Childhood moyamoya disease: hemodynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tzika, A.A. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Robertson, R.L. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Barnes, P.D. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Vajapeyam, S. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Burrows, P.E. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Treves, S.T. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Scott, R.M. l [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States)

    1997-09-01

    Background. Childhood moyamoya disease is a rare progressive cerebrovascular disease. Objective. To evaluate cerebral hemodynamics using dynamic Gd-DTPA-enhanced imaging in children with moyamoya disease. Materials and methods. Eight children (2-11 years of age) with the clinical and angiographic findings typical of moyamoya disease, before and/or after surgical intervention (pial synangiosis), underwent conventional MR imaging (MRI) and hemodynamic MR imaging (HMRI). HMRI used a spoiled gradient-echo with low flip angle (10 deg) and long TE (TR/TE = 24/15 ms) to minimize T 1 effects and emphasize T 2{sup *} weighting. Raw and calculated hemodynamic images were reviewed. Three-dimensional time-of-flight MR angiography (MRA) and perfusion brain single photon emission computed tomography (SPECT) were also performed. Results. Abnormal hemodynamic maps resulting from vascular stenosis or occlusion and basal collaterals were observed in six patient studies. HMRI depicted perfusion dynamics of affected cerebrovascular territories, detected cortical perfusion deficits, and complemented conventional MRI and MRA. HMRI findings were consistent with those of catheter angiography and perfusion SPECT. Conclusion. Our preliminary experience suggests that HMRI may be of value in the preoperative and postoperative evaluation of surgical interventions in moyamoya disease. (orig.). With 4 figs., 3 tabs.

  4. [Hemodynamic changes in hypoglycemic shock].

    Science.gov (United States)

    Gutiérrez, C; Piza, R; Chousleb, A; Hidalgo, M A; Ortigosa, J L

    1977-01-01

    Severe hypoglycemia may be present in seriously ill patients; if it is not corrected opportunely a series of neuroendocrinal mechanisms take place aimed at correcting metabolic alterations. These mechanisms can produce hemodynamic alterations as well. Nine mongrel dogs were studied with continuous registration of: blood pressure, central venous pressure, cardiac frequency, respiratory frequency, electrocardiogram and first derivative (Dp/Dt). Six dogs received crystalline (fast acting) insuline intravenously (group 1). After hemodynamic changes were registered hypoglycemia was corrected with 50 per cent glucose solution. Complementary insuline doses were administered to three dogs (group 2); in this group hypoglycemia was not corrected. In group 1 during hypoglycemia there was an increase in blood pressure, central venous pressure, cardiac frequency, respiratory frequency and Dp/Dt, and changes in QT and T wave on the EKG; these changes were partially reversible after hypoglycemia was corrected. The above mentioned alterations persisted in group 2, breathing became irregular irregular and respiratory arrest supervened. It can be inferred that the hemodynamic response to hypoglycemia is predominantly adrenergic. The role of catecolamines, glucocorticoides, glucagon, insuline, cyclic AMP in metabolic and hemodynamic alterations consecutive to hypoglycemia are discussed.

  5. Hemodynamic characteristics of hyperplastic remodeling lesions in cerebral aneurysms.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Furukawa

    Full Text Available Hyperplastic remodeling (HR lesions are sometimes found on cerebral aneurysm walls. Atherosclerosis is the results of HR, which may cause an adverse effect on surgical treatment for cerebral aneurysms. Previous studies have demonstrated that atherosclerotic changes had a correlation with certain hemodynamic characteristics. Therefore, we investigated local hemodynamic characteristics of HR lesions of cerebral aneurysms using computational fluid dynamics (CFD.Twenty-four cerebral aneurysms were investigated using CFD and intraoperative video recordings. HR lesions and red walls were confirmed on the intraoperative images, and the qualification points were determined on the center of the HR lesions and the red walls. The qualification points were set on the virtual operative images for evaluation of wall shear stress (WSS, normalized WSS (NWSS, oscillatory shear index (OSI, relative residence time (RRT, and aneurysm formation indicator (AFI. These hemodynamic parameters at the qualification points were compared between HR lesions and red walls.HR lesions had lower NWSS, lower AFI, higher OSI and prolonged RRT compared with red walls. From analysis of the receiver-operating characteristic curve for hemodynamic parameters, OSI was the most optimal hemodynamic parameter to predict HR lesions (area under the curve, 0.745; 95% confidence interval, 0.603-0.887; cutoff value, 0.00917; sensitivity, 0.643; specificity, 0.893; P<0.01. With multivariate logistic regression analyses using stepwise method, NWSS was significantly associated with the HR lesions.Although low NWSS was independently associated with HR lesions, OSI is the most valuable hemodynamic parameter to distinguish HR lesions from red walls.

  6. Long-term occupational stress is associated with regional reductions in brain tissue volumes.

    Directory of Open Access Journals (Sweden)

    Eva Blix

    Full Text Available There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM and white matter (WM volumes, and the volumes of hippocampus, caudate, and putamen - structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment.

  7. Assessment of Cracks in Stress Concentration Regions with Localized Plastic Zones

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, E.

    1998-11-25

    Marty brittle fracture evaluation procedures include plasticity corrections to elastically computed stress intensity factors. These corrections, which are based on the existence of a plastic zone in the vicinity of the crack tip, can overestimate the plasticity effect for a crack embedded in a stress concentration region in which the elastically computed stress exceeds the yield strength of the material in a localized zone. The interactions between the crack, which acts to relieve the high stresses driving the crack, plasticity effects in the stress concentration region, and the nature and source of the loading are examined by formulating explicit flaw finite element models for a crack emanating from the root of a notch located in a panel subject to an applied tensile stress. The results of these calculations provide conditions under which a crack-tip plasticity correction based on the Irwin plastic zone size overestimates the plasticity effect. A failure assessment diagram (FAD) curve is used to characterize the effect of plasticity on the crack driving force and to define a less restrictive plasticity correction for cracks at notch roots when load-controlled boundary conditions are imposed. The explicit flaw finite element results also demonstrate that stress intensity factors associated with load-controlled boundary conditions, such as those inherent in the ASME Boiler and Pressure Vessel Code as well as in most handbooks of stress intensity factors, can be much higher than those associated with displacement-controlled conditions, such as those that produce residual or thermal stresses. Under certain conditions, the inclusion of plasticity effects for cracks loaded by displacement-controlled boundary conditions reduces the crack driving force thus justifying the elimination of a plasticity correction for such loadings. The results of this study form the basis for removing unnecessary conservatism from flaw evaluation procedures that utilize plasticity

  8. Postural effects on hemodynamic response to interpersonal interaction.

    Science.gov (United States)

    Waldstein, S R; Neumann, S A; Merrill, J A

    1998-05-01

    Laboratory studies of stress-induced cardiovascular reactivity have been conducted predominantly with participants in a seated posture. This procedure may contribute to limited laboratory-field generalization of cardiovascular response. The present study examined hemodynamic adjustments underlying pressor responses, in addition to heart rate and systolic time intervals, during seated and standing role-played, interpersonal interaction in 60 young adults. Irrespective of gender or race, blood pressure responses to the seated and standing interactions were comparable. However, seated interactions yielded a significantly greater increase in heart rate, shortened preejection period and decreased stroke index as compared to standing. Alternatively, interacting while standing yielded a significantly increased left ventricular ejection time and total peripheral resistance in comparison to sitting. These results suggest that hemodynamic adjustments during stressful interpersonal interaction vary as a function of posture, with somewhat greater cardiac influences apparent while seated and a more pronounced vascular response while standing.

  9. Review: hemodynamic response to carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Penney, D.G.

    1988-04-01

    Historically, and at present, carbon monoxide is a major gaseous poison responsible for widespread morbidity and mortality. From threshold to maximal nonlethal levels, a variety of cardiovascular changes occur, both immediately and in the long term, whose homeostatic function it is to renormalize tissue oxygen delivery. However, notwithstanding numerous studies over the past century, the literature remains equivocal regarding the hemodynamic responses in animals and humans, although CO hypoxia is clearly different in several respects from hypoxic hypoxia. Factors complicating interpretation of experimental findings include species, CO dose level and rate, route of CO delivery, duration, level of exertion, state of consciousness, and anesthetic agent used. Augmented cardiac output usually observed with moderate COHb may be compromised in more sever poisoning for the same reasons, such that regional or global ischemia result. The hypotension usually seen in most animal studies is thought to be a primary cause of CNS damage resulting from acute CO poisoning, yet the exact mechanism(s) remains unproven in both animals and humans, as does the way in which CO produces hypotension. This review briefly summarizes the literature relevant to the short- and long-term hemodynamic responses reported in animals and humans. It concludes by presenting an overview using data from a single species in which the most complete work has been done to date.

  10. Crustal stress field in the Greek region inferred from inversion of moment tensor solutions

    Science.gov (United States)

    Konstantinou, Konstantinos; Mouslopoulou, Vasiliki; Liang, Wen-Tzong; Heidbach, Oliver; Oncken, Onno; Suppe, John

    2016-04-01

    The Hellenic region is the seismically most active area in Europe, having experienced numerous large magnitude catastrophic earthquakes and associated devastating tsunamis. A means of mitigating these potential hazards is by better understanding the patterns of spatial and temporal deformation of the crust across the Hellenic orogenic system, over timescales that range from individual earthquakes to several tens of years. In this study for the first time we make collective use of the Global CMT (GCMT), Regional CMT (RCMT) and National Observatory of Athens (NOA) moment tensor databases in order to extract focal mechanism solutions that will be used to infer crustal stresses in the Greek region at an unprecedented resolution. We focus on the shallow seismicity within the upper plate (down to 42 km) and select solutions with good waveform fits and well-resolved hypocentral depths. In this way we obtained 1,614 focal mechanism solutions covering western Greece up to southern Albania, central and southern Greece, northern Aegean as well as the subduction trench west and east of Crete. These solutions are used as input to a regional-scale damped stress inversion over a grid whose node spacing is 0.35 degrees for the purpose of recovering the three principal stress axes and the stress ratio R for each node. Several sensitivity tests are performed where parameters such as damping, hypocentral depth, magnitude range are varied, in order to ascertain the robustness of our results. The final stress field model is then compared to the GPS-derived strain field revealing an excellent agreement between the two datasets. Additionally, maximum and minimum stress axes orientations are correlated with the strike and dip of known faults in order to improve our understanding of future fault rupture and corresponding seismic hazard.

  11. Socioeconomic inequalities and mental stress in individual and regional level: a twenty one cities study in China.

    Science.gov (United States)

    Wang, Hongmei; Yang, Xiaozhao Y; Yang, Tingzhong; Cottrell, Randall R; Yu, Lingwei; Feng, Xueying; Jiang, Shuhan

    2015-03-07

    This study will examine explanatory variables including socioeconomic inequalities related to mental stress at both the individual and regional level. A cross-sectional multistage sampling process was used to obtain participants. Data on mental stress and individual socioeconomic status were gathered via face to face interview. Regional variables were retrieved from a national database. Multilevel logistic regression analysis was used to assess socioeconomic variances in mental stress. Among the 16,866 participants, 27.2% reported severe levels of mental stress (95% CI: 19.4%-35.1%). Multilevel regression analysis indicated that lower individual educational attainment and income, and lower regional Per Capita GDP was associated with mental stress. The results also indicated that managers, clerks, and professional workers manifested higher stress levels than those in other occupations. Based on the results of this study individual and regional socioeconomic inequalities in China are associated with mental stress.

  12. Vascular remodeling of the mouse yolk sac requires hemodynamic force

    OpenAIRE

    Lucitti, Jennifer L.; Jones, Elizabeth; Huang, Chengqun; Chen, Ju; Fraser, Scott E.; Dickinson, Mary E.

    2007-01-01

    The embryonic heart and vessels are dynamic and form and remodel while functional. Much has been learned about the genetic mechanisms underlying the development of the cardiovascular system, but we are just beginning to understand how changes in heart and vessel structure are influenced by hemodynamic forces such as shear stress. Recent work has shown that vessel remodeling in the mouse yolk sac is secondarily effected when cardiac function is reduced or absent. These findings indicate that p...

  13. Pharmacological Modulation of Hemodynamics in Adult Zebrafish In Vivo.

    Directory of Open Access Journals (Sweden)

    Daniel Brönnimann

    Full Text Available Hemodynamic parameters in zebrafish receive increasing attention because of their important role in cardiovascular processes such as atherosclerosis, hematopoiesis, sprouting and intussusceptive angiogenesis. To study underlying mechanisms, the precise modulation of parameters like blood flow velocity or shear stress is centrally important. Questions related to blood flow have been addressed in the past in either embryonic or ex vivo-zebrafish models but little information is available for adult animals. Here we describe a pharmacological approach to modulate cardiac and hemodynamic parameters in adult zebrafish in vivo.Adult zebrafish were paralyzed and orally perfused with salt water. The drugs isoprenaline and sodium nitroprusside were directly applied with the perfusate, thus closely resembling the preferred method for drug delivery in zebrafish, namely within the water. Drug effects on the heart and on blood flow in the submental vein were studied using electrocardiograms, in vivo-microscopy and mathematical flow simulations.Under control conditions, heart rate, blood flow velocity and shear stress varied less than ± 5%. Maximal chronotropic effects of isoprenaline were achieved at a concentration of 50 μmol/L, where it increased the heart rate by 22.6 ± 1.3% (n = 4; p < 0.0001. Blood flow velocity and shear stress in the submental vein were not significantly increased. Sodium nitroprusside at 1 mmol/L did not alter the heart rate but increased blood flow velocity by 110.46 ± 19.64% (p = 0.01 and shear stress by 117.96 ± 23.65% (n = 9; p = 0.03.In this study, we demonstrate that cardiac and hemodynamic parameters in adult zebrafish can be efficiently modulated by isoprenaline and sodium nitroprusside. Together with the suitability of the zebrafish for in vivo-microscopy and genetic modifications, the methodology described permits studying biological processes that are dependent on hemodynamic alterations.

  14. Assessment of the hemodynamic changes after EDAS combined with bifrontal EGS in pediatric patients with moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yoo Sung; Kim, Yu Kyeong; Lee, Jae Sung; Kim, Seung Ki; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    To assess the effect of encephaloduroarteriosynangiosis (EDAS) with or without bifrontal encephalogaleosynangiosis (EGS) in children with moyamoya disease, we evaluated cerebral hemodynamic changes using brain Tc-99m HMPAO SPECT. Total 34 pediatric patients (M: F=12:22, mean age;93 yrs) enrolled. Bypass surgery for both hemispheres (EDAS with EGS on one side, and EDAS on the other side) in 25 patients, unilateral EDAS with EGS in 7, and unilateral EDAS only in 2 were underwent. Perfusion SPECT before surgery, and 4 to 18 months after final surgery were done. The vascular territories for ICA, MCA and the brain regions for the frontal, parietal, temporal, and the occipital cortices were determined using standard ROls based on K-SPAM. Additionally, medial frontal cortex was selected to assess the effect of EGS. Basal/acetazolamide challenged cerebral blood flow (CBF), and cerebral vascular index (CVRI) were determined using normalized regional brain uptake to the cerebellum. 24 patients became symptom free, and 6 were improved but having some residual symptoms at the last follow up period. The other 3 were worsened after operation. Overall basal/acetazolamide stress CBF and CVRI for each brain region after surgery were increased, however, only the changes of CVRI were significant. Meanwhile, the improvement of CBF or CVRI in the brain regions ipsilateral to the hemisphere having EDAS with EGS was not significantly different when compared with those for the brain regions with EDAS only. Also, the hemodynamic improvement for the mesial frontal cortex in patients after EDAS with EGS was not significant, and showed no difference with those in patient with EDAS only. Quantitative perfusion SPECT demonstrated the hemodynamic improvement after EDAS with or without EGS in pediatric moyamoya disease. Cerebrovascular reserve showed meaningful improvement after surgery, implicating the effect of vascular anastomosis in ischemic areas.

  15. Multiphase hemodynamic simulation of pulsatile flow in a coronary artery.

    Science.gov (United States)

    Jung, Jonghwun; Lyczkowski, Robert W; Panchal, Chandrakant B; Hassanein, Ahmed

    2006-01-01

    A multiphase transient non-Newtonian three-dimensional (3-D) computational fluid dynamics (CFD) simulation has been performed for pulsatile hemodynamics in an idealized curved section of a human coronary artery. We present the first prediction, to the authors' knowledge, of particulate buildup on the inside curvature using the multiphase theory of dense suspension hemodynamics. In this study, the particulates are red blood cells (RBCs). The location of RBC buildup on the inside curvature correlates with lower wall shear stress (WSS) relative to the outside curvature. These predictions provide insight into how blood-borne particulates interact with artery walls and hence, have relevance for understanding atherogenesis since clinical observations show that atherosclerotic plaques generally form on the inside curvatures of arteries. The buildup of RBCs on the inside curvature is driven by the secondary flow and higher residence times. The higher viscosity in the central portion of the curved vessel tends to block their flow, causing them to migrate preferentially through the boundary layer. The reason for this is the nearly neutrally buoyant nature of the dense two-phase hemodynamic flow. The two-phase non-Newtonian viscosity model predicts greater shear thinning than the single-phase non-Newtonian model. Consequently, the secondary flow induced in the curvature is weaker. The waveforms for computed hemodynamic parameters, such as hematocrit, WSS, and viscosity, follow the prescribed inlet velocity waveforms. The lower oscillatory WSS produced on the inside curvature has implications for understanding thickening of the intimal layer.

  16. Microarray analysis of regional cellular responses to local mechanical stress in acute lung injury.

    Science.gov (United States)

    Simon, Brett A; Easley, R Blaine; Grigoryev, Dmitry N; Ma, Shwu-Fan; Ye, Shui Q; Lavoie, Tera; Tuder, Rubin M; Garcia, Joe G N

    2006-11-01

    Human acute lung injury is characterized by heterogeneous tissue involvement, leading to the potential for extremes of mechanical stress and tissue injury when mechanical ventilation, required to support critically ill patients, is employed. Our goal was to establish whether regional cellular responses to these disparate local mechanical conditions could be determined as a novel approach toward understanding the mechanism of development of ventilator-associated lung injury. We utilized cross-species genomic microarrays in a unilateral model of ventilator-associated lung injury in anesthetized dogs to assess regional cellular responses to local mechanical conditions that potentially contribute pathogenic mechanisms of injury. Highly significant regional differences in gene expression were observed between lung apex/base regions as well as between gravitationally dependent/nondependent regions of the base, with 367 and 1,544 genes differentially regulated between these regions, respectively. Major functional groupings of differentially regulated genes included inflammation and immune responses, cell proliferation, adhesion, signaling, and apoptosis. Expression of genes encoding both acute lung injury-associated inflammatory cytokines and protective acute response genes were markedly different in the nondependent compared with the dependent regions of the lung base. We conclude that there are significant differences in the local responses to stress within the lung, and consequently, insights into the cellular responses that contribute to ventilator-associated lung injury development must be sought in the context of the mechanical heterogeneity that characterizes this syndrome.

  17. Dissociation of dorsal hippocampal regional activation under the influence of stress in freely behaving rats

    Directory of Open Access Journals (Sweden)

    Johannes ePassecker

    2011-10-01

    Full Text Available Stress has deleterious effects on brain, body and behaviour in humans and animals alike. The present work investigated how 30-minute acute photic stress exposure impacts on spatial information processing in the main subregions of the dorsal hippocampal formation (CA1, CA3 and Dentate Gyrus, a brain structure prominently implicated in memory and spatial representation. Recordings were performed from spatially tuned hippocampal and dentate gyrus cells in rats while animals foraged in a square arena for food. The stress procedure induced a decrease in firing frequencies in CA1 and CA3 place cells while sparing locational characteristics. In contrast to the CA1-CA3 network, acute stress failed to induce major changes in the DG neuronal population. These data demonstrate a clear dissociation of the effects of stress on the main hippocampal sub-regions. Our findings further support the notion of decreased hippocampal excitability arising from stress in areas CA1 and CA3, but not in dentate gyrus.

  18. Estimating ecological water stress caused by anthropogenic uses in the US Great Lakes region

    Science.gov (United States)

    Alian, S.; Mayer, A. S.; Maclean, A.; Watkins, D. W., Jr.; Gyawali, R.; Mirchi, A.

    2016-12-01

    Anthropocentric water resources management that prioritizes socio-economic growth can cause harmful ecological water stress by depriving aquatic ecosystems of the water needed to sustain habitats. It is important to better understand the impacts of water withdrawal by different economic sectors (e.g., agriculture, power utilities, manufacturing, etc.), withdrawal sources, and extent of return flow (i.e., return of water to river system) at different spatial and temporal scales in order to characterize potentially harmful streamflow disturbances, and to inform water management. Herein, GIS technology is used to characterize and map ecological water stress in the Great Lakes region by compiling and analyzing water withdrawal data for different use categories. An integrative geospatial method is developed to quantify catchment scale streamflow disturbance as the sum of flow depletion and return flow, and propagate it along the stream network in order to calculate water stress index as function of consumptive use and impacted streamflow. Results for the Kalamazoo River Watershed, Michigan, illustrate that although average annual and July water stress is generally relatively low, protective management actions may be necessary in a significant number of catchments, especially in urban catchments with very high water stress. Water stress is significantly higher under low flow conditions, indicating the need to adjust withdrawals to reduce adverse resource impacts on sensitive streams.

  19. Increased moth herbivory associated with environmental stress of pinyon pine at local and regional levels.

    Science.gov (United States)

    Cobb, N S; Mopper, S; Gehring, Catherine A; Caouette, Matt; Christensen, Kerry M; Whitham, Thomas G

    1997-02-01

     Using 6 years of observational and experimental data, we examined the hypothesis that water and nutrient stress increase the susceptibility of pinyon pine (Pinus edulis) to the stem- and cone-boring moth (Dioryctria albovittella). At two geographic levels, a local scale of 550 km2 and a regional scale of 10,000 km2, moth herbivory was strongly correlated with an edaphic stress gradient. At a local scale, from the cinder soils of Sunset Crater to nearby sandy-loam soils, nine of ten soil macro- and micronutrients, and soil water content were lowest in cinder-dominated soils. Herbivore damage was six times greater on trees growing in the most water and nutrient deficient site at Sunset Crater compared to sites with well-developed soils. Percentage silt-clay content of soil, which was highly positively correlated with soil nutrient and soil moisture at a local scale, accounted for 56% of the variation in herbivory at a regional scale among 22 sites. Within and across sites, increased stem resin flow was positively associated with reduced moth attack. On the basis of moth distribution across a stress gradient, we predicted that pinyons growing in highly stressful environments would show increased resistance to herbivores if supplemented with water and/or nutrients. We conducted a 6-year experiment at a high-stress site where individual trees received water only, fertilizer only, and water + fertilizer. Relative to control trees, stem growth and resin flow increased in all three treatments, but only significantly in the water + fertilizer treatment. Although there was no significant difference in herbivore damage among these three treatments, there was an overall reduction in herbivore damage on all treatment trees combined, compared to control trees. This experiment suggests that release from stress leads to increased resistance to insect attack and is consistent with our observational data. While other studies have predicted that short-term stress will result in

  20. Groundwater development stress: Global-scale indices compared to regional modeling

    Science.gov (United States)

    Alley, William; Clark, Brian R.; Ely, Matt; Faunt, Claudia

    2018-01-01

    The increased availability of global datasets and technologies such as global hydrologic models and the Gravity Recovery and Climate Experiment (GRACE) satellites have resulted in a growing number of global-scale assessments of water availability using simple indices of water stress. Developed initially for surface water, such indices are increasingly used to evaluate global groundwater resources. We compare indices of groundwater development stress for three major agricultural areas of the United States to information available from regional water budgets developed from detailed groundwater modeling. These comparisons illustrate the potential value of regional-scale analyses to supplement global hydrological models and GRACE analyses of groundwater depletion. Regional-scale analyses allow assessments of water stress that better account for scale effects, the dynamics of groundwater flow systems, the complexities of irrigated agricultural systems, and the laws, regulations, engineering, and socioeconomic factors that govern groundwater use. Strategic use of regional-scale models with global-scale analyses would greatly enhance knowledge of the global groundwater depletion problem.

  1. Active stress field and seismotectonic features in Intra-Carpathian region of Romania

    Science.gov (United States)

    Oros, Eugen; Popa, Mihaela; Diaconescu, Mihai; Radulian, Mircea

    2017-04-01

    The Romanian Intra-Carpathian Region is located on the eastern half of Tisa-Dacia geodynamic block from the Neogene Carpathian-Pannonian Basin. The distribution of seismicity displays clear clusters and narrower zones with seismogenic potential confirmed by the damaging earthquakes recoded in the region, e.g. July 01, 1829 (Mw=6.2), October 10, 1834 (Mw=5.6), January 26, 1916 (Mw=6.4), July 12, 1991 (Mw=5.7), December 2, 1991 (Mw=5.5). The state of recent stress and deformation appears to be controlled by the interaction of plate-boundary and intraplate forces, which include the counterclockwise rotation and N-NE-directed indentation of the Adria microplate and buoyancy forces associated with differential topography and lithospheric heterogeneities. The stress field and tectonic regime are investigated at regional and local scales by the formal inversion of focal mechamisms. There can be observed short-scale lateral changes of i) tectonic regimes from compressive (reverse and strike-slip faultings) to pure extensive (normal faultings) and ii) variation of stress directions (SHmax) from NE-SW to EW and WNW-ESE towards Southern Carpathians and NS within Easter Carpathians. The changes in stress directions occur over a distance that is comparable to or smaller than the thickness of the lithosphere. A comparative analysis of stress tensor with GPS velocity/displacememt vectors shows variations from paralellism to orthogonality, suggesting different mechanisms of crustal deformations.The major seismic activity (Mw≥5.0) appears to be generally concentrated along the faults systems bordering de Tisa-Dacia Block, intersections of faults of different ages, internal shear zones and with the border of the former structural terrains, old rifts and neostructures.

  2. Psychological distress and stressful life events in pediatric complex regional pain syndrome

    OpenAIRE

    Julia Wager; Hannah Brehmer; Gerrit Hirschfeld; Boris Zernikow

    2015-01-01

    BACKGROUND: There is little knowledge regarding the association between psychological factors and complex regional pain syndrome (CRPS) in children. Specifically, it is not known which factors precipitate CRPS and which result from the ongoing painful disease. OBJECTIVES: To examine symptoms of depression and anxiety as well as the experience of stressful life events in children with CRPS compared with children with chronic primary headaches and functional abdominal pain. METHODS: A retrospec...

  3. Significant correlation between autonomic nervous activity and cerebral hemodynamics during thermotherapy on the neck.

    Science.gov (United States)

    Yasui, Hiroshi; Takamoto, Kouich; Hori, Etsuro; Urakawa, Susumu; Nagashima, Yoshinao; Yada, Yukihiro; Ono, Taketoshi; Nishijo, Hisao

    2010-08-25

    Although local thermotherapy reduces mental stress and neck stiffness, its physiological mechanisms are still not fully understood. We speculated that local thermotherapy exerts its effect, in addition to its direct peripheral effects, through the central nervous system that is involved in controlling stress responses. In the present study, we investigated the effects of a heat- and steam-generating (HSG) sheet on cerebral hemodynamics and autonomic nervous activity using near-infrared spectroscopy (NIRS) and the electrocardiograms (ECGs). Thirteen healthy young female subjects participated in this study. HSG or simple (control) sheets were repeatedly applied to the neck for 120 s with 180 s intervals of rest between applications. During the experiment, brain hemodynamic responses (changes in Oxy-Hb, Deoxy-Hb, and Total-Hb) and autonomic nervous activity based on heart rate variability (HRV) were monitored. Subjective perception of neck stiffness and fatigue was significantly improved after application of the HSG sheet. NIRS findings indicated that the application of HSG sheets decreased Oxy-Hb concentration in the anterior-dorsal region of the medial prefrontal cortex (adMPFC), while increasing parasympathetic nervous activity and decreasing sympathetic nervous activity. Furthermore, changes in Oxy-Hb in the adMPFC were significantly and negatively correlated with those in parasympathetic nervous activity during application of the HSG sheet. These findings suggest that application of the HSG sheet to the neck region induced mental relaxation and ameliorated neck stiffness by modifying activity of the adMPFC. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Regional left ventricular myocardial contractility and stress in a finite element model of posterobasal myocardial infarction.

    Science.gov (United States)

    Wenk, Jonathan F; Sun, Kay; Zhang, Zhihong; Soleimani, Mehrdad; Ge, Liang; Saloner, David; Wallace, Arthur W; Ratcliffe, Mark B; Guccione, Julius M

    2011-04-01

    Recently, a noninvasive method for determining regional myocardial contractility, using an animal-specific finite element (FE) model-based optimization, was developed to study a sheep with anteroapical infarction (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001). Using the methodology developed in the previous study (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001), which incorporates tagged magnetic resonance images, three-dimensional myocardial strains, left ventricular (LV) volumes, and LV cardiac catheterization pressures, the regional myocardial contractility and stress distribution of a sheep with posterobasal infarction were investigated. Active material parameters in the noninfarcted border zone (BZ) myocardium adjacent to the infarct (T(max_B)), in the myocardium remote from the infarct (T(max_R)), and in the infarct (T(max_I)) were estimated by minimizing the errors between FE model-predicted and experimentally measured systolic strains and LV volumes using the previously developed optimization scheme. The optimized T(max_B) was found to be significantly depressed relative to T(max_R), while T(max_I) was found to be zero. The myofiber stress in the BZ was found to be elevated, relative to the remote region. This could cause further damage to the contracting myocytes, leading to heart failure.

  5. Clarifications on Continuous Renal Replacement Therapy and Hemodynamics

    Directory of Open Access Journals (Sweden)

    Xiao-Ting Wang

    2017-01-01

    Conclusions: CRRT is not only a replacement for organ function, but an important form of hemodynamic therapy. Improved hemodynamic management of critically ill patients can be achieved by establishing specific therapeutic hemodynamic targets and maintaining circulatory stability during CRRT. Over the long term, observation of renal hemodynamics will provide greater opportunities for the progression of CRRT hemodynamic therapy.

  6. Psychological distress and stressful life events in pediatric complex regional pain syndrome

    Science.gov (United States)

    Wager, Julia; Brehmer, Hannah; Hirschfeld, Gerrit; Zernikow, Boris

    2015-01-01

    BACKGROUND: There is little knowledge regarding the association between psychological factors and complex regional pain syndrome (CRPS) in children. Specifically, it is not known which factors precipitate CRPS and which result from the ongoing painful disease. OBJECTIVES: To examine symptoms of depression and anxiety as well as the experience of stressful life events in children with CRPS compared with children with chronic primary headaches and functional abdominal pain. METHODS: A retrospective chart study examined children with CRPS (n=37) who received intensive inpatient pain treatment between 2004 and 2010. They were compared with two control groups (chronic primary headaches and functional abdominal pain; each n=37), who also received intensive inpatient pain treatment. Control groups were matched with the CRPS group with regard to admission date, age and sex. Groups were compared on symptoms of depression and anxiety as well as stressful life events. RESULTS: Children with CRPS reported lower anxiety and depression scores compared with children with abdominal pain. A higher number of stressful life events before and after the onset of the pain condition was observed for children with CRPS. CONCLUSIONS: Children with CRPS are not particularly prone to symptoms of anxiety or depression. Importantly, children with CRPS experienced more stressful life events than children with chronic headaches or abdominal pain. Prospective long-term studies are needed to further explore the potential role of stressful life events in the etiology of CRPS. PMID:26035287

  7. Stressful life events and psychological dysfunction in Complex Regional Pain Syndrome type I.

    Science.gov (United States)

    Geertzen, J H; de Bruijn-Kofman, A T; de Bruijn, H P; van de Wiel, H B; Dijkstra, P U

    1998-06-01

    To determine to what extent stressful life events and psychological dysfunction play a role in the pathogenesis of Complex Regional Pain Syndrome type I (CRPS). A comparative study between a CRPS group and a control group. Stressful life events and psychological dysfunction evaluation was performed with a life event rating list and the Symptom Checklist-90 (SCL-90). A university hospital. The CRPS group consisted of 24 patients with a history of upper extremity CRPS of less than 3 months. The control group consisted of 42 hand pathology patients waiting for elective hand surgery within the next 24 hours. Stressful life event rating was measured using the Social Readjustment Rating Scale. Psychological dysfunction was measured using the SCL-90. Stressful life events were experienced by 19 patients (79.2%) in the CRPS group and by 9 patients (21.4%) in the control group. This difference was significant. Testing of psychological dysfunction (SCL-90) in CRPS patients and the control group demonstrated some significant differences: male patients were more anxious than male controls; female patients were statistically more depressed, had feelings of inadequacy, and were emotionally less stable than female controls. In multivariate analysis, no significant differences were found across gender, age, or gender x group interactions. Of the SCL-90 dimensions, only insomnia correlated with the experienced stressful life events. Stressful life events are more common in the CRPS group, which indicates that there may be a multiconditional model of CRPS. The experience of stressful life events besides trauma or surgery are risk factors, not causes, in such a model.

  8. Lack of evidence for an association between hemodynamic variables and hematoma growth in spontaneous intracerebral hemorrhage.

    Science.gov (United States)

    Jauch, Edward C; Lindsell, Christopher J; Adeoye, Opeolu; Khoury, Jane; Barsan, William; Broderick, Joseph; Pancioli, Arthur; Brott, Thomas

    2006-08-01

    Early hematoma expansion in spontaneous intracerebral hemorrhage (ICH) is associated with worse clinical outcome. We hypothesized that hemodynamic parameters are associated with the increase in hematoma volume owing to their relationship to blood vessel wall stresses. We performed a post hoc analysis of clinical and computed tomography (CT) data from patients enrolled in a prospective observational study of ICH patients presenting within 3 hours from symptom onset. Hematoma volumes were measured at hospital arrival and at 1 and 20 hours from presentation. Blood pressure and heart rate, recorded at 19 time points between presentation and 20 hours, were used to derive hemodynamic variables. Multivariable logistic-regression models were constructed to assess the relation between hemodynamic parameters and hematoma growth, adjusted for clinical covariates. From the original study, 98 patients underwent baseline and 1-hour CT scans; of these, 65 had 20-hour CT scans. Substantial hematoma growth was observed in 28% within the first hour. Of the 65 patients not undergoing surgery within 20 hours, 37% experienced hematoma growth by 20 hours. Neither baseline or peak hemodynamic parameters nor changes in hemodynamic parameters were significantly associated with hematoma growth at either 1 or 20 hours. We found no blood pressure or heart rate parameters, individually or in combination, that were associated with hematoma growth. Our data suggest the influence of hemodynamic parameters on vessel wall stress to be an unlikely target for intervention in reducing the risk of early hematoma growth in ICH.

  9. Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Jiren Xu

    2009-01-01

    Full Text Available Various earthquake fault types, mechanism solutions and stress fields, as well as GPS and geothermal data are analyzed for the study of the crustal movements on the Tibetan plateau and their tectonic implications. The results show that a lot of the normal faulting type-event concentrated at altitudes greater than 4000 m on the central Tibetan plateau. The altitudes concentrating normal faulting type-events can be zoned two parts: the western part, the Lhasa block, and the eastern part, the Qiangtang-Changdu region. The azimuths of T-axes are in a general E-W direction in the Lhasa block and NW-SE or NNW-SSE in the Qiangtang-Changdu region at the altitudes of the Tibetan plateau. The tensional stresses in E-W direction and NW-SE direction predominate normal faulting earthquake occurrence in the Lhasa block and the Qiangtang-Changdu region, respectively. The slipping displacements of the normal-faulting-type events have great components in near E-W direction and NW-SE direction in the Lhasa block and the Qiangtang-Changdu region, respectively. The extensions are probably an eastward or southeastward extensional motion, being mainly tectonic activity phenomena in the plateau altitudes. The extensional motions due to normal-fault earthquakes are important tectonic activity regimes on the high altitudes of the plateau. The easterly crustal extensions on the plateau are attributable to the gravitational collapse of the high plateau and eastward extrusion of hotter mantle materials beneath the eastern boundary of the plateau. Numbers of thrust-fault and strike-slip-fault earthquakes with strong compressive stress in a general NNE-SSW direction occur on the edges of the plateau.

  10. Micro-buckling of periodically layered composites in regions of stress concentration

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Niordson, Christian Frithiof

    2016-01-01

    -buckling related failure in regions of stress concentrations. A series of parametric studies show the effect of non-uniform stress distributions due to bending loads and the presence of geometrical features such as notches and holes on the initiation of micro-buckling. The contribution of the bending stiffness...... of the reinforcing layers on the resistance against micro-buckling introduces a dependence on the layer thickness, resulting in size-scale dependent strength limits. Therefore, both the shape and dimensions of the considered geometrical features and the layering thickness of the micro-structure are varied as part...... of the parametric studies. Moreover, the impact of imperfections in the composite micro-structure on the strength of the considered specimens is investigated....

  11. Hemodynamics Influences Vascular Peroxynitrite Formation: Implication for LDL Apo B-100 Nitration

    OpenAIRE

    Hsiai, Tzung K.; Hwang, Juliana; Barr, Mark L.; Correa, Adria; Hamilton, Ryan; Alavi, Mohammad; Rouhanizadeh, Mahsa; Cadenas, Enrique; Hazen, Stanley L

    2006-01-01

    Hemodynamics, specifically, fluid shear stress, modulates the focal nature of atherogenesis. Superoxide anion (O2−.) reacts with nitric oxide (.NO) at a rapid diffusion-limited rate to form peroxynitrite (O2−. +.NO → ONOO−). Immunohistostaining of human coronary arterial bifurcations or curvatures, where oscillatory shear stress (OSS) develops, revealed presence of nitrotyrosine staining, a fingerprint of peroxynitrite; whereas in straight segments, where pulsatile shear stress (PSS) occurs, ...

  12. Preliminary study of hemodynamic distribution in patient-specific stenotic carotid bifurcation by image-based computational fluid dynamics.

    Science.gov (United States)

    Xue, Y-J; Gao, P-Y; Duan, Q; Lin, Y; Dai, C-B

    2008-06-01

    Regions prone to atherosclerosis, such as bends and bifurcations, tend to exhibit a certain degree of non-planarity or curvature, and these geometric features are known to strongly influence local flow patterns. Recently, computational fluid dynamics (CFD) has been used as a means of enhancing understanding of the mechanisms involved in atherosclerotic plaque formation and development. To analyze flow patterns and hemodynamic distribution in stenotic carotid bifurcation in vivo by combining CFD with magnetic resonance angiography (MRA). Twenty-one patients with carotid atherosclerosis proved by digital subtraction angiography (DSA) and/or Doppler ultrasound underwent contrast-enhanced MR angiography of the carotid bifurcation by a 3.0T MR scanner. Hemodynamic variables and flow patterns of the carotid bifurcation were calculated and visualized by combining vascular imaging postprocessing with CFD. In mild stenotic cases, there was much more streamlined flow in the bulbs, with reduced or disappeared areas of weakly turbulent flow. Also, the corresponding areas of low wall shear stress (WSS) were reduced or even disappeared. As the extent of stenosis increased, stronger blood jets formed at the portion of narrowing, and more prominent eddy flows and slow back flows were noted in the lee of the stenosis. Regions of elevated WSS were predicted at the portion of stenosis and in the path of the downstream jet. Areas of low WSS were predicted on the leeward side of the stenosis, corresponding with the location of slowly turbulent flows. CFD combined with MRA can simulate flow patterns and calculate hemodynamic variables in stenotic carotid bifurcations as well as normal ones. It provides a new method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.

  13. College crisis intervention: an initiative to develop regional campus Critical Incident Stress Management teams.

    Science.gov (United States)

    Wiesen, F Elizabeth; Lischer, David K

    2006-01-01

    This article presents a statewide initiative that was undertaken to develop regional Critical Incident Stress Management (CISM) teams among colleges and universities within a northeastern state. In light of the unique needs and culture of institutions of higher education, this initiative was intended to improve each member college or university's capacity to respond comprehensively and effectively to critical incidents that affect its community. A step-by-step description of the implementation of the initiative is presented as well as discussion of what was learned through the process and future directions.

  14. The professional stress of nurses employed in medical institutions in the Lublin Region

    OpenAIRE

    Michalik, Joanna; Zawadka, Magdalena; Wolski, Dariusz; Stanisławek, Andrzej; Węgorowski, Paweł

    2017-01-01

    Michalik Joanna, Zawadka Magdalena, Wolski Dariusz, Stanisławek Andrzej, Węgorowski Paweł. The professional stress of nurses employed in medical institutions in the Lublin Region. Journal of Education, Health and Sport. 2017;7(8):296-308. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.847992 http://ojs.ukw.edu.pl/index.php/johs/article/view/4732 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 12...

  15. Cerebrovascular hemodynamics during pranayama techniques

    Directory of Open Access Journals (Sweden)

    L Nivethitha

    2017-01-01

    Full Text Available Background: Pranayama techniques are known to produce variable physiological effects on the body. We evaluated the effect of the two commonly practiced Pranayama techniques on cerebral hemodynamics. Materials and Methods: Fifteen healthy male volunteers, trained in Yoga and Pranayama, were included in the study. Mean age was 24 years (range 22–32 years. Study participants performed 2 Pranayamas in 2 different orders. Order 1 (n = 7 performed Bhastrika (bellows breaths followed by Kumbhaka (breath retention while order 2 (n = 8 performed Kumbhaka followed by Bhastrika. Both breathing techniques were performed for 1 min each. Continuous transcranial Doppler (TCD monitoring was performed during the breathing techniques. TCD parameters that were recorded included peak systolic velocity (PSV, end-diastolic velocity (EDV, mean flow velocity (MFV, and pulsatility index (PI of the right middle cerebral artery at baseline, 15, 30, 45, and 60 s. Results: Significant reductions in EDV (3.67 ± 6.48; P< 0.001 and MFV (22.00 ± 7.30; P< 0.001 with a significant increase in PI (2.43 ± 0.76; P< 0.001 were observed during Bhastrika. On the contrary, a significant increase in PSV (65.27 ± 13.75; P< 0.001, EDV (28.67 ± 12.03; P< 0.001, and MFV (43.67 ± 12.85; P< 0.001 with a significant reduction in PI (0.89 ± 0.28; P< 0.01 was observed only during Kumbhaka. Conclusion: Bhastrika and Kumbhaka practices of Pranayama produce considerable and opposing effects on cerebral hemodynamic parameters. Our findings may play a potential role in designing the Pranayama techniques according to patients' requirements.

  16. Hemodynamic effects of ventricular defibrillation

    Science.gov (United States)

    Pansegrau, Donald G.; Abboud, François M.

    1970-01-01

    Hemodynamic responses to ventricular defibrillation were studied in anesthetized dogs. Observations were made on arterial, right atrial and left ventricular end-diastolic pressures, on cardiac output (dye dilution), heart rate, and right atrial electrocardiogram. Ventricular fibrillation was induced electrically with a bipolar electrode catheter placed in the right ventricle. Fibrillation was maintained for 15 or 30 sec and terminated with a 400 w sec capacitor discharge across the thoracic cage. Responses lasted 1-10 min after conversion and included a cholinergic and an adrenergic component. The cholinergic component was characterized by sinus bradycardia, periods of sinus arrest, atrioventricular block, and ventricular premature beats. The adrenergic component included increases in arterial pressure, in cardiac output, and in left ventricular stroke work at a time when left ventricular end-diastolic pressure was normal; there was no change in total peripheral resistance. The pH of arterial blood decreased slightly and pCO2 increased but pO2 and the concentration of lactate were unchanged. Bilateral vagotomy and intravenous administration of atropine blocked the cholinergic component, unmasked a sinus tachycardia, and accentuated the adrenergic component of the response. The latter was blocked by intravenous administration of propranolol and phenoxybenzamine. These responses were related primarily to conversion of ventricular fibrillation rather than to the electrical discharge of countershock because countershock without ventricular fibrillation caused more transient and smaller responses than those observed with defibrillation: furthermore, the hemodynamic effects of defibrillation were augmented by prolongation of the duration of fibrillation. The results suggest that the cholinergic component of the response may be detrimental in that it favors spontaneous recurrence of fibrillation; on the other hand, the adrenergic component may be essential for conversion

  17. Investigating the Influence of Regional Stress on Fault and Fracture Permeability at Pahute Mesa, Nevada National Security Site

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Donald M. [Desert Research Inst. (DRI), Reno, NV (United States); Smith, Kenneth D. [Univ. of Nevada, Reno, NV (United States); Parashar, Rishi [Desert Research Inst. (DRI), Reno, NV (United States); Collins, Cheryl [Desert Research Inst. (DRI), Las Vegas, NV (United States); Heintz, Kevin M. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2017-05-24

    Regional stress may exert considerable control on the permeability and hydraulic function (i.e., barrier to and/or conduit for fluid flow) of faults and fractures at Pahute Mesa, Nevada National Security Site (NNSS). In-situ measurements of the stress field are sparse in this area, and short period earthquake focal mechanisms are used to delineate principal horizontal stress orientations. Stress field inversion solutions to earthquake focal mechanisms indicate that Pahute Mesa is located within a transtensional faulting regime, represented by oblique slip on steeply dipping normal fault structures, with maximum horizontal stress ranging from N29°E to N63°E and average of N42°E. Average horizontal stress directions are in general agreement with large diameter borehole breakouts from Pahute Mesa analyzed in this study and with stress measurements from other locations on the NNSS.

  18. Morphological and hemodynamic analysis of mirror posterior communicating artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Jinyu Xu

    Full Text Available BACKGROUND AND PURPOSE: Hemodynamic factors are commonly believed to play an important role in the pathogenesis, progression, and rupture of cerebral aneurysms. In this study, we aimed to identify significant hemodynamic and morphological parameters that discriminate intracranial aneurysm rupture status using 3-dimensional-angiography and computational fluid dynamics technology. MATERIALS AND METHODS: 3D-DSA was performed in 8 patients with mirror posterior communicating artery aneurysms (Pcom-MANs. Each pair was divided into ruptured and unruptured groups. Five morphological and three hemodynamic parameters were evaluated for significance with respect to rupture. RESULTS: The normalized mean wall shear stress (WSS of the aneurysm sac in the ruptured group was significantly lower than that in the unruptured group (0.52±0.20 versus 0.81±0.21, P = .012. The percentage of the low WSS area in the ruptured group was higher than that in the unruptured group (4.11±4.66% versus 0.02±0.06%, P = .018. The AR was 1.04±0.21 in the ruptured group, which was significantly higher than 0.70±0.17 in the unruptured group (P = .012. By contrast, parameters that had no significant differences between the two groups were OSI (P = .674, aneurysm size (P = .327, size ratio (P = .779, vessel angle (P = 1.000 and aneurysm inclination angle (P = 1.000. CONCLUSIONS: Pcom-MANs may be a useful disease model to investigate possible causes of aneurysm rupture. The ruptured aneurysms manifested lower WSS, higher percentage of low WSS area, and higher AR, compared with the unruptured one. And hemodynamics is as important as morphology in discriminating aneurysm rupture status.

  19. Evaluation of hemodynamic significance of coronary fistulae. Diagnostic integration between coronary angiography and stress/rest myocardial scintigraphy; Valutazione del significato emodinamico di fistole coronariche artero-venose. Integrazione diagnostica tra angiografia coronarica e scintigrafia miocardica a riposo e sotto sforzo

    Energy Technology Data Exchange (ETDEWEB)

    Rubini, G.; Sebastiani, M. [Bari Univ., Bari (Italy). Cattedra di Medicina Nucleare; Ettorre, G. C. [Foggia Univ., Foggia (Italy). Cattedra di Radiologia; Bovenzi, F. [Ospedale Policlinico, Unita' Operativa di Cardiologia, Bari (Italy)

    2000-12-01

    It is here reported on the importance of the integration of data obtained from digital coronary angiography and stress/rest {sup 99m}Tc sestamibi myocardial perfusion single photon emission tomography in evaluationing the hemodynamic significance of coronary arteriovenous fistulae. Coronary fistulae were detected with coronary angiography in 9 patients. All patients underwent clinical examination, trans thoracic echocardiography, stress electrocardiogram and stress/rest {sup 99m}Tc sestamibi myocardial perfusion single photon emission tomography. Stress/rest {sup 99m}Tc sestamibi myocardial perfusion single photon tomography and stress electrocardiogram showed stress-induced myocardial ischemia in 2 patients. The first patient with familial predisposition and risk factors for ischemic heart disease presented a mesocardic heart murmur on clinical examination. At stress ECG (125 Watt, 153 b/m max frequency 93%, arterial pressure 230 mmHg, max frequency pressure product 35200) ischemic alterations were recorded at the first minute of the second stage of the Bruce protocol. Coronary angiography detected a circumflex artery fistula in the coronary sinus. Stress/rest {sup 99m}Tc sestamibi myocardial perfusion single photon emission tomography for the evaluation of stress/rest perfusion detected a reversible perfusion defect of the proximal portion of the posterolateral and lateral walls, thus confirming the hemodynamic importance of the flow through the fistula during stress cycloergometric testing. In the second patient familial predisposition to ischemic heart disease and previous inferior wall myocardial infarction and non-significant stress ECG, coronary angiography identified a suocclusive stenosis of the right coronary artery and anomaly between the anterior interventricular artery and the left pulmonary artery. The presence of the contrast medium in the left pulmonary artery identified a flow from the left ventricle to the left pulmonary artery. Good angiographic

  20. Estresse de enfermeiros em unidade de hemodinâmica no Rio Grande do Sul, Brasil Estrés de enfermeros en una unidad de hemodinámica en Rio Grande do Sul, Brasil Stress in nurses at a hemodynamics ward in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Graciele Fernanda da Costa Linch

    2011-03-01

    Full Text Available A pesquisa teve como objetivo avaliar a relação entre estresse e sintomas apresentados pelos enfermeiros que atuam em unidades de hemodinâmica. Os dados foram coletados por questionário. Para análise, os resultados foram considerados estatisticamente significativos se pLa investigación objetivó evaluar la relación entre el estrés y los síntomas presentados por los enfermeros que actúan en unidades de hemodinámica. Los datos fueron recogidos a través de un cuestionario. Para el análisis, los resultados fueron considerados estadísticamente significativos (pThis study aimed to evaluate the relationship between stress and symptoms reported by nurses working in units hemodynamics. Data were collected by questionnaire. For analysis, the results were considered statistically significant if p<0.05, with an interval of 95% confidence. The population consisted of 63 nurses with a predominance of females (90.5% and average age of 35.24 (± 8.21 years. Most was attended postgraduate (77.8% and did not have another job (77.8%. The stress, 52.4% of nurses had an average between 1.11 and 1.97, classified as medium stress, and the field was critical situations of the highest score (1.63 ± 0.29. Regarding symptoms, the domain skeletal muscle had a higher average (1.39 ± 0.94. In this study, there was high significant positive correlation between stress and symptoms (r=0.629, p<0.001, thus it is concluded that stress is directly related to the symptoms presented by the nurses.

  1. Early cerebral hemodynamic, metabolic and histological changes in hypoxic-ischemic fetal lambs during postnatal life

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    Carmen eRey-Santano

    2011-09-01

    Full Text Available The hemodynamic, metabolic and biochemical changes produce during transition from fetal to neonatal life could be aggravated if asphyctic event occur during fetal life. The aim of the study was to examine the regional cerebral blood flow (RCBF, histological changes, and cerebral brain metabolism in preterm lambs, and to analyze the role of oxidative stress for the first hours of postnatal life following severe fetal asphyxia. 18 chronically instrumented fetal lambs were assigned to: hypoxic-ischemic group, following fetal asphyxia animals were delivered and maintained on intermittent-positive-pressure-ventilation for 3 hours, and non-injured animals that were managed similarly to the previous group and used as control group. During hypoxic-ischemic insult, injured group developed acidosis, hypoxia, hypercapnia, latacidaemia and tachycardia in comparison to control group, without hypotension. Intermittent-positive-pressure-ventilation transiently improved gas exchange and cardiovascular parameters. After HI injury and during ventilation-support, the increased RCBF in inner zones was maintained for hypoxic-ischemic group, but cortical flow did not exhibit differences compared to the control group. Also, the increase of TUNEL positive cells (apoptosis and antioxidant enzymes, and decrease of ATP reserves was significantly higher in the brain regions where the RCBF were not increased.In conclusion, early metabolic, histological and hemodynamic changes involved in brain damage have been intensively investigated and reported in premature asphyctic lambs for the first 3 hours of postnatal life. Those changes have been described in human neonates, so our model could be useful to test the security and the effectiveness of different neuroprotective or ventilatory strategies when are applied in the first hours after fetal hypoxic-ischemic injury.

  2. Stress Field in Brazil with Focal Mechanism: Regional and Local Patterns

    Science.gov (United States)

    Dias, F.; Assumpcao, M.

    2013-05-01

    The knowledge of stress field is fundamental not only to understand driving forces and plate deformation but also in the study of intraplate seismicity. The stress field in Brazil has been determined mainly using focal mechanisms and a few breakout data and in-situ measurements. However the stress field still is poorly known in Brazil. The focal mechanisms of recent earthquakes (magnitude lower than 5 mb) were studied using waveform modeling. We stacked the record of several teleseismic stations ( delta > 30°) stacked groups of stations separated according to distance and azimuth. Every record was visually inspected and those with a good signal/noise ratio (SNR) were grouped in windows of ten degrees distance and stacked. The teleseismic P-wave of the stacked signals was modeled using the hudson96 program of Herrmann seismology package (Herrmann, 2002) and the consistency of focal mechanism with the first-motion was checked. Some events in central Brazil were recorded by closer stations (~ 1000 km) and the moment tensor was determined with the ISOLA code (Sokos & Zahradnik, 2008). With the focal mechanisms available in literature and those obtained in this work, we were able to identify some patterns: the central region shows a purely compressional pattern (E-W SHmax), which is predicted by regional theoretical models (Richardson & Coblentz, 1996 and the TD0 model of Lithgow & Bertelloni, 2004). Meanwhile in the Amazon we find an indication of SHmax oriented in the SE-NW direction, probably caused by the Caribbean plate interaction (Meijer, 1995). In northern coastal region, the compression rotates following the coastline, which indicates an important local component related to spreading effects at the continental/oceanic transition (Assumpção, 1998) and flexural stresses caused by sedimentary load in Amazon Fan. We determine the focal mechanism of several events in Brazil using different techniques according to the available data. The major difficulty is to

  3. Effects of Nuclear Factor-E2-related factor 2/Heme Oxygenase 1 on splanchnic hemodynamics in experimental cirrhosis with portal hypertension.

    Science.gov (United States)

    Qin, Jun; He, Yue; Duan, Ming; Luo, Meng

    2017-05-01

    We explored the effects of Nuclear Factor-E2-related factor 2 (Nrf2) and Heme Oxygenase 1 (HO-1) on splanchnic hemodynamics in portal hypertensive rats. Experimental cirrhosis with portal hypertension was induced by intraperitoneal injection of carbon tetrachloride. The expression of proteins was examined by immunoblotting. Hemodynamic studies were performed by radioactive microspheres. The vascular perfusion system was used to measure the contractile response of mesentery arterioles in rats. Nrf2 expression in the nucleus and HO-1 expression in cytoplasm was significantly enhanced in portal hypertensive rats. Portal pressure, as well as regional blood flow, increased significantly in portal hypertension and can be blocked by tin protoporphyrin IX. The expression of endogenous nitric oxide synthase and vascular endothelial growth factors increased significantly compared to normal rats, while HO-1 inhibition decreased the expression of these proteins significantly. The contractile response of mesenteric arteries decreased in portal hypertension, but can be partially recovered through tin protoporphyrin IX treatment. The expression of Nrf2/HO-1 increased in mesenteric arteries of portal hypertensive rats, which was related to oxidative stress. HO-1was involved in increased portal pressure and anomaly splanchnic hemodynamics in portal hypertensive rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Do mesoscale faults near the tip of an active strike-slip fault indicate regional or local stress?

    Science.gov (United States)

    Yamaji, Atsushi

    2017-04-01

    Fault-slip analysis is used in Japan after the Great Tohoku Earthquake (2011) to judge the stability of fractures in the foundations of nuclear power plants. In case a fault-slip datum from a fracture surface is explained by the present stress condition, the fracture is thought to have a risk to be activated as a fault. So, it is important to understand the relative significance of regional and local stresses. To answer the question whether mesoscale faults indicate regional or local stress, fault-slip data were collected from the walls of a trenching site of the Nojima Fault in central Japan—an active, dextral, strike-slip fault. The fault gave rise to the 1995 Kobe earthquake, which killed more than 6000 people. The trench was placed near the fault tip, which produced compressional and extensional local stress conditions on the sides of the fault near the tip. A segment of the fault, which ruptured the surface in 1995, bounded Cretaceous granite and latest Pliocene sediments in the trench. As a result, the stress inversion of the data from the mesoscale faults observed in the trench showed both the local stresses. The present WNW-ESE regional compression was found from the compressive side, but was not in the extensional side, probably because local extension surpassed the regional compression. Instead, the regional N-S compression of the Early Pleistocene was found from the extensional side. From this project, we got the lesson that fault-slip analysis reveals regional and local stresses, and that local stress sometimes masks regional one. This work was supported by a science project of "Drilling into Fault Damage Zone" (awarded to A. Lin) of the Secretariat of Nuclear Regulation Authority (Japan).

  5. Regional mechanical properties and stress analysis of the human anterior lens capsule.

    Science.gov (United States)

    Pedrigi, R M; David, G; Dziezyc, J; Humphrey, J D

    2007-06-01

    The lens capsule of the eye functions, in part, as a deformable support through which the ciliary body applies tractions that can alter lens curvature and corresponding refractive power during the process of accommodation. Although it has long been recognized that characterization of the mechanical properties of the lens capsule is fundamental to understanding this physiologic process as well as clinical interventions, prior data have been limited by one-dimensional testing of excised specimens despite the existence of multiaxial loading in vivo. In this paper, we employ a novel experimental approach to study in situ the regional, multiaxial mechanical behavior of both normal and diabetic human anterior lens capsules. Furthermore, we use these data to calculate material parameters in a nonlinear stress-strain relation via a custom sub-domain inverse finite element method (FEM). These parameters are then used to predict capsular stresses in response to imposed loads using a forward FEM model. Our results for both normal and diabetic human eyes show that the anterior lens capsule exhibits a nonlinear pseudoelastic behavior over finite strains that is typical of soft tissues, and that strains are principal relative to meridional and circumferential directions. Experimental data and parameter estimation suggest further that the capsule is regionally anisotropic, with the circumferential direction becoming increasingly stiffer than the meridional direction towards the equator. Although both normal and diabetic lens capsules exhibited these general characteristic behaviors, diabetic capsules were significantly stiffer at each distension. Finally, the forward FEM model predicted a nearly uniform, equibiaxial stress field during normalcy that will be perturbed by cataract surgery. Such mechanical perturbations may be an underlying modulator of the sustained errant epithelial cell behavior that is observed well after cataract surgery and may ultimately contribute to

  6. Social support modulates stress-related gene expression in various brain regions of piglets

    Directory of Open Access Journals (Sweden)

    Ellen Kanitz

    2016-11-01

    Full Text Available The presence of an affiliative conspecific may alleviate an individual's stress response in threatening conditions. However, the mechanisms and neural circuitry underlying the process of social buffering have not yet been elucidated. Using the domestic pig as an animal model, we examined the effect of a 4-h maternal and littermate deprivation on stress hormones and on mRNA expression of the glucocorticoid receptor (GR, mineralocorticoid receptor (MR, 11ß-hydroxysteroid dehydrogenase (11ß-HSD types 1 and 2 and the immediate early gene c-fos in various brain regions of 7-, 21- and 35-day old piglets. The deprivation occurred either alone or with a familiar or unfamiliar age-matched piglet. Compared to piglets deprived alone, the presence of a conspecific animal significantly reduced free plasma cortisol concentrations and altered the MR/GR balance and 11ß-HSD2 and c-fos mRNA expression in the prefrontal cortex (PFC, amygdala and hypothalamus, but not in the hippocampus. The alterations in brain mRNA expression were particularly found in 21- or 35-day old piglets, which may reflect the species-specific postnatal ontogeny of the investigated brain regions. The buffering effects of social support were most pronounced in the amygdala, indicating its significance both for the assessment of social conspecifics as biologically relevant stimuli and for the processing of emotional states. In conclusion, the present findings provide further evidence for the importance of the cortico-limbic network underlying the abilities of individuals to cope with social stress and strongly emphasize the benefits of social partners in livestock with respect to positive welfare and health.

  7. Hemodynamic Monitorization of the Burn Patient

    Directory of Open Access Journals (Sweden)

    Ahmet Coşar

    2011-07-01

    Full Text Available Hemodynamic monitorization is the basic component of the medical care of the burn patients. It provides valuable information of the cardiopulmonary performance which is essential in the rapid diagnosis and treatment in the case of hemodynamic disturbance. The clinical importance of any monitorization parameter, associated risks – benefits, cost effectivity, and also assessment and management skills of the health care providers should be taken into consideration in the selection process of the monitorization method. This paper reviews the methods of the hemodynamic monitorization for the clinical care of the burn patients. (Journal of the Turkish Society Intensive Care 2011; 9 Suppl: 11-20

  8. Chronic stress and moderate physical exercise prompt widespread common activation and limited differential activation in specific brain regions.

    Science.gov (United States)

    Kim, Tae-Kyung; Han, Pyung-Lim

    2016-10-01

    Chronic stress in rodents produces depressive behaviors, whereas moderate physical exercise counteracts stress-induced depressive behaviors. Chronic stress and physical exercise appear to produce such opposing effects by changing the neural activity of specific brain regions. However, the detailed mechanisms through which the two different types of stimuli regulate brain function in opposite directions are not clearly understood. In the present study, we attempted to explore the neuroanatomical substrates mediating stress-induced behavioral changes and anti-depressant effects of exercise by examining stimulus-dependent c-Fos induction in the brains of mice that were exposed to repeated stress or exercise in a scheduled manner. Systematic and integrated analyses of c-Fos expression profiles indicated that various brain areas, including the prelimbic cortex, lateral septal area, and paraventricular nuclei of hypothalamus were commonly and strongly activated by both stress and exercise, while the lateral habenula and hippocampus were identified as being preferentially activated by stress and exercise, respectively. Exercise-dependent c-Fos expression in all regions examined in the brain occurred in both glutamatergic and GABAergic neurons. These results suggest that chronic stress and moderate exercise produce counteractive effects on mood behaviors, along with prompting widespread common activation and limited differential activation in specific brain regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Determining the Potential Role of Regional Stress on Preferential Flow and Transport at Pahute Mesa, Nevada National Security Site

    Science.gov (United States)

    Reeves, D. M.; Smith, K. D.; Parashar, R.; Kevin, H. M.

    2016-12-01

    Pahute Mesa is a structurally complex region on the Nevada National Security Site consisting of multiple calderas and faults associated with Basin and Range tectonics. Ground water flows primarily through fractured volcanic rocks in a northeast to southwest direction. Kilometer-scale tritium and plutonium migration from the Benham underground test suggests ground water velocities on the order of 50 m/yr. Regional stress may exert considerable control on the hydraulic properties of large faults and smaller fractures at Pahute Mesa. In-situ measurements of the stress field are sparse, and short period earthquake focal mechanisms are used in this study to delineate principal horizontal stress orientations. Overall, event depths and short period mechanisms in the Pahute Mesa area are often poorly constrained. Stress field inversion solutions from the earthquake focal mechanism data indicate that Pahute Mesa is within a transtensional faulting regime with a maximum horizontal stress direction ranging from N29°E to N63°E with an average of N42°E. This maximum horizontal stress trend is supported by breakout data from large diameter boreholes. A computer code that incorporates stress field inversion solutions is used to compute dilation and slip tendency metrics for digitized fault and caldera structural margin segments according to both average and space-varying horizontal stress directions. Faults with the highest dilation trend NE-SW for both average and space-varying stress field solutions, and are lowest for NW-SE structures. The distribution of slip tendency is similar with maximum values below that required for a critically stressed designation. This implies that the resolution of normal stress acting on fault planes in Pahute Mesa may play a larger role on fault permeability than shear stress within the modern stress field. Inflow locations along boreholes and a series of large-scale aquifer tests are currently being analyzed to investigate potential

  10. Regional Stress-Induced Ischemia in Non-fibrotic Hypertrophied Myocardium in Young HCM Patients.

    Science.gov (United States)

    Jablonowski, Robert; Fernlund, Eva; Aletras, Anthony H; Engblom, Henrik; Heiberg, Einar; Liuba, Petru; Arheden, Håkan; Carlsson, Marcus

    2015-12-01

    The relationship between hypertrophy, perfusion abnormalities and fibrosis is unknown in young patients with hypertrophic cardiomyopathy (HCM). Since mounting evidence suggests causal relationship between myocardial ischemia and major adverse cardiac events, we sought to investigate whether (1) regional myocardial perfusion is decreased in young HCM patients and in individuals at risk of HCM, and (2) hypoperfused areas are larger than areas with fibrosis. HCM patients (n = 12), HCM-risk subjects (n = 15) and controls (n = 9) were imaged on a 1.5 T MRI scanner. Myocardial hypertrophy was assessed on cine images. Perfusion images were acquired during adenosine hyperemia and at rest. Maximum upslope ratios of perfusion (stress/rest) were used for semiquantitative analysis. Fibrosis was assessed by late gadolinium enhancement (LGE). Results are presented as median and range. Perfusion in HCM-risk subjects and in non-hypertrophied segments in HCM patients showed no difference compared to controls (P = ns). Hypertrophic segments in HCM patients without LGE showed decreased perfusion compared to segments without hypertrophy [1.5 (1.1-2.3) vs. 2.0 (1.8-2.6), P myocardium in HCM patients during adenosine exceeded the extent of fibrosis on LGE [20 (0-48) vs. 4 (0-7) % slice area, P myocardium and is lowest in fibrotic myocardium in young HCM patients but does not discriminate HCM-risk subjects from controls. The stress-induced hypoperfused regions exceed regions with LGE, indicating that hypoperfusion precedes fibrosis and may be a more sensitive marker of diseased myocardium in HCM.

  11. The Stressed Female Brain: Neuronal activity in the prelimbic but not infralimbic region of the medial prefrontal cortex suppresses learning after acute stress

    Directory of Open Access Journals (Sweden)

    Lisa Y. Maeng

    2013-12-01

    Full Text Available Women are nearly twice as likely as men to suffer from anxiety and post-traumatic stress disorder (PTSD, indicating that many females are especially vulnerable to stressful life experience. A profound sex difference in the response to stress is also observed in laboratory animals. Acute exposure to an uncontrollable stressful event disrupts associative learning during classical eyeblink conditioning in female rats but enhances this same type of learning process in males. These sex differences in response to stress are dependent on neuronal activity in similar but also different brain regions. Neuronal activity in the basolateral nucleus of the amygdala (BLA is necessary in both males and females. However, neuronal activity in the medial prefrontal cortex (mPFC during the stressor is necessary to modify learning in females but not in males. The mPFC is often divided into its prelimbic (PL and infralimbic (IL subregions, which differ both in structure and function. Through its connections to the BLA, we hypothesized that neuronal activity within the PL, but not IL, during the stressor is necessary to suppress learning in females. To test this hypothesis, either the PL or IL of adult female rats was bilaterally inactivated with GABAA agonist muscimol during acute inescapable swim stress. 24h later, all subjects were trained with classical eyeblink conditioning. Though stressed, females without neuronal activity in the PL learned well. In contrast, females with IL inactivation during the stressor did not learn well, behaving similar to stressed vehicle-treated females. These data suggest that exposure to a stressful event critically engages the PL, but not IL, to disrupt associative learning in females. Together with previous studies, these data indicate that the PL communicates with the BLA to suppress learning after a stressful experience in females. This circuit may be similarly engaged in women who become cognitively impaired after stressful

  12. The stressed female brain: neuronal activity in the prelimbic but not infralimbic region of the medial prefrontal cortex suppresses learning after acute stress.

    Science.gov (United States)

    Maeng, Lisa Y; Shors, Tracey J

    2013-01-01

    Women are nearly twice as likely as men to suffer from anxiety and post-traumatic stress disorder (PTSD), indicating that many females are especially vulnerable to stressful life experience. A profound sex difference in the response to stress is also observed in laboratory animals. Acute exposure to an uncontrollable stressful event disrupts associative learning during classical eyeblink conditioning in female rats but enhances this same type of learning process in males. These sex differences in response to stress are dependent on neuronal activity in similar but also different brain regions. Neuronal activity in the basolateral nucleus of the amygdala (BLA) is necessary in both males and females. However, neuronal activity in the medial prefrontal cortex (mPFC) during the stressor is necessary to modify learning in females but not in males. The mPFC is often divided into its prelimbic (PL) and infralimbic (IL) subregions, which differ both in structure and function. Through its connections to the BLA, we hypothesized that neuronal activity within the PL, but not IL, during the stressor is necessary to suppress learning in females. To test this hypothesis, either the PL or IL of adult female rats was bilaterally inactivated with GABAA agonist muscimol during acute inescapable swim stress. About 24 h later, all subjects were trained with classical eyeblink conditioning. Though stressed, females without neuronal activity in the PL learned well. In contrast, females with IL inactivation during the stressor did not learn well, behaving similarly to stressed vehicle-treated females. These data suggest that exposure to a stressful event critically engages the PL, but not IL, to disrupt associative learning in females. Together with previous studies, these data indicate that the PL communicates with the BLA to suppress learning after a stressful experience in females. This circuit may be similarly engaged in women who become cognitively impaired after stressful life

  13. Coherent hemodynamics spectroscopy: initial applications in the neurocritical care unit

    Science.gov (United States)

    Tgavalekos, Kristen T.; Sassaroli, Angelo; Cai, Xuemei; Kornbluth, Joshua; Fantini, Sergio

    2017-02-01

    We used coherent hemodynamics spectroscopy (CHS) and near-infrared spectroscopy (NIRS) to measure the absolute cerebral blood flow (CBF) and cerebral autoregulation efficiency of a patient with intraventricular hemorrhage in the neurocritical care unit. Mean arterial pressure oscillations were induced with cyclic thigh cuff inflations at a super-systolic pressure. The oscillations in oxyhemoglobin ([HbO2]) and deoxyhemoglobin ([Hb]) cerebral concentrations were used to compute CHS amplitude and phase spectra that were fit with the frequency-domain equations of our hemodynamic model. From the fitted parameters, we obtained measures of local autoregulation efficiency (cutoff frequency: 0.07 +/- 0.02 Hz) and absolute regional CBF (33 +/- 9 ml/100g/min). We introduce a new approach for computing CHS spectra using coherence criteria and time-varying transfer function analysis. We show that with this approach we can maximize the number of frequency points in the CHS spectra for more effective fitting with our hemodynamic model. Finally, we show how absolute measurements of the cerebral concentrations of [HbO2] and [Hb] at baseline can be used to further enhance the fitting procedure.

  14. Fetal brain activity and hemodynamic response to a vibroacoustic stimulus.

    Science.gov (United States)

    Fulford, Jonathan; Vadeyar, Shantala H; Dodampahala, Sanani H; Ong, Stephen; Moore, Rachel J; Baker, Philip N; James, David K; Gowland, Penny

    2004-06-01

    Previous studies have demonstrated the practicality of using functional magnetic resonance imaging (fMRI) techniques to assess fetal brain activity. The purpose of this study was to compare the fetal hemodynamic response to that of the adult. Seventeen pregnant subjects, all of whom were at more than 36 weeks gestation were scanned while the fetus was exposed to a vibroacoustic stimulus. Thirteen adult subjects were scanned with an equivalent acoustic stimulus. Of the fetal subjects, two could not be analyzed due to technical problems, eight did not show significant activation, and seven showed significant activation. In all cases, activation was localized within the temporal region. Measures of fetal hemodynamic responses revealed an average time to peak (ttp) of 7.36 +/- 0.94 sec and an average percentage change of 2.67 +/- 0.93%. In contrast, activation was detected in 5 of 13 adults with an average ttp of 6.54 +/- 0.54 sec and an average percentage change of 1.02 +/- 0.40%. The measurement of changes in the fetal hemodynamic response may be important in assessing compromised pregnancies. Copyright 2004 Wiley-Liss, Inc.

  15. Hemodynamic Monitorization of the Burn Patient

    OpenAIRE

    Ahmet Coşar; Burak Eşkin

    2011-01-01

    Hemodynamic monitorization is the basic component of the medical care of the burn patients. It provides valuable information of the cardiopulmonary performance which is essential in the rapid diagnosis and treatment in the case of hemodynamic disturbance. The clinical importance of any monitorization parameter, associated risks – benefits, cost effectivity, and also assessment and management skills of the health care providers should be taken into consideration in the selection process of ...

  16. Methodology for Computer-aided, Interactive Rapid Assessment of Local or Regional Stress Fields on Mars

    Science.gov (United States)

    Colton, S. L.; Ferrill, D. A.; Sims, D. W.; Wyrick, D. Y.; Franklin, N. M.

    2003-03-01

    We present a method for rapid assessment of stress fields on Mars: (i) mapping geologic structures, (ii) calculating stress fields, and (iii) determining resolved stresses on faults. Preliminary results are presented for northern Utopia Planitia.

  17. Stress

    Science.gov (United States)

    ... natural disaster. This type of stress can cause post-traumatic stress disorder (PTSD). Different people may feel stress in different ways. Some people experience digestive symptoms. Others may have headaches, sleeplessness, depressed mood, anger, ...

  18. Hemodynamics of a hydrodynamic injection

    Directory of Open Access Journals (Sweden)

    Tsutomu Kanefuji

    2014-01-01

    Full Text Available The hemodynamics during a hydrodynamic injection were evaluated using cone beam computed tomography (CBCT and fluoroscopic imaging. The impacts of hydrodynamic (5 seconds and slow (60 seconds injections into the tail veins of mice were compared using 9% body weight of a phase-contrast medium. Hydrodynamically injected solution traveled to the heart and drew back to the hepatic veins (HV, which led to liver expansion and a trace amount of spillover into the portal vein (PV. The liver volumes peaked at 165.6 ± 13.3% and 165.5 ± 11.9% of the original liver volumes in the hydrodynamic and slow injections, respectively. Judging by the intensity of the CBCT images at the PV, HV, right atrium, liver parenchyma (LP, and the inferior vena cava (IVC distal to the HV conjunction, the slow injection resulted in the higher intensity at PV than at LP. In contrast, a significantly higher intensity was observed in LP after hydrodynamic injection in comparison with that of PV, suggesting that the liver took up the iodine from the blood flow. These results suggest that the enlargement speed of the liver, rather than the expanded volume, primarily determines the efficiency of hydrodynamic delivery to the liver.

  19. Hemodynamics driven cardiac valve morphogenesis.

    Science.gov (United States)

    Steed, Emily; Boselli, Francesco; Vermot, Julien

    2016-07-01

    Mechanical forces are instrumental to cardiovascular development and physiology. The heart beats approximately 2.6 billion times in a human lifetime and heart valves ensure that these contractions result in an efficient, unidirectional flow of the blood. Composed of endocardial cells (EdCs) and extracellular matrix (ECM), cardiac valves are among the most mechanically challenged structures of the body both during and after their development. Understanding how hemodynamic forces modulate cardiovascular function and morphogenesis is key to unraveling the relationship between normal and pathological cardiovascular development and physiology. Most valve diseases have their origins in embryogenesis, either as signs of abnormal developmental processes or the aberrant re-expression of fetal gene programs normally quiescent in adulthood. Here we review recent discoveries in the mechanobiology of cardiac valve development and introduce the latest technologies being developed in the zebrafish, including live cell imaging and optical technologies, as well as modeling approaches that are currently transforming this field. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. Copyright © 2015. Published by Elsevier B.V.

  20. Central Hemodynamics and Microcirculation in Critical Conditions

    Directory of Open Access Journals (Sweden)

    A. A. Kosovskikh

    2013-01-01

    Full Text Available Objective: to compare central hemodynamic and microcirculatory changes in critical conditions caused by different factors and to reveal their possible differences for a further differentiated approach to intensive therapy. Subjects and methods. The study covered 16 subjects with severe concomitant injury (mean age 41.96±2.83 years and 19 patients with general purulent peritonitis (mean age 45.34±2.16 years. Their follow-up was 7 days. The central hemodynamics was estimated by transpulmonary thermodilution using a Pulsion PiCCO Plus system (Pulsion Medical Systems, Germany. The microcirculatory bed was evaluated by cutaneous laser Doppler flowmetry using a LAKK-02 capillary blood flow laser analyzer (LAZMA Research-and-Production Association, Russian Federation. Results. The pattern of central hemodynamic and microcirculatory disorders varies with the trigger that has led to a critical condition. Central hemodynamics should be stabilized to ensure the average level of tissue perfusion in victims with severe concomitant injury. In general purulent peritonitis, microcirculatory disorders may persist even if the macrohemodynamic parameters are normal. Conclusion. The macrohemodynamic and microcirculatory differences obtained during the study suggest that a complex of intensive therapy should be differentiated and, if the latter is used, it is necessary not only to be based on the central hemodynamics, but also to take into consideration functional changes in microcirculation. Key words: severe concomitant injury, general purulent peritonitis, micro-circulation, central hemodynamics, type of circulation.

  1. Investigation of hemodynamics in the development of dissecting aneurysm within patient-specific dissecting aneurismal aortas using computational fluid dynamics (CFD) simulations.

    Science.gov (United States)

    Tse, Kwong Ming; Chiu, Peixuan; Lee, Heow Pueh; Ho, Pei

    2011-03-15

    Aortic dissecting aneurysm is one of the most catastrophic cardiovascular emergencies that carries high mortality. It was pointed out from clinical observations that the aneurysm development is likely to be related to the hemodynamics condition of the dissected aorta. In order to gain more insight on the formation and progression of dissecting aneurysm, hemodynamic parameters including flow pattern, velocity distribution, aortic wall pressure and shear stress, which are difficult to measure in vivo, are evaluated using numerical simulations. Pulsatile blood flow in patient-specific dissecting aneurismal aortas before and after the formation of lumenal aneurysm (pre-aneurysm and post-aneurysm) is investigated by computational fluid dynamics (CFD) simulations. Realistic time-dependent boundary conditions are prescribed at various arteries of the complete aorta models. This study suggests the helical development of false lumen around true lumen may be related to the helical nature of hemodynamic flow in aorta. Narrowing of the aorta is responsible for the massive recirculation in the poststenosis region in the lumenal aneurysm development. High pressure difference of 0.21 kPa between true and false lumens in the pre-aneurismal aorta infers the possible lumenal aneurysm site in the descending aorta. It is also found that relatively high time-averaged wall shear stress (in the range of 4-8 kPa) may be associated with tear initiation and propagation. CFD modeling assists in medical planning by providing blood flow patterns, wall pressure and wall shear stress. This helps to understand various phenomena in the development of dissecting aneurysm. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Influence of high deformation rate, brain region, transverse compression, and specimen size on rat brain shear stress morphology and magnitude.

    Science.gov (United States)

    Haslach, Henry W; Gipple, Jenna M; Leahy, Lauren N

    2017-04-01

    An external mechanical insult to the brain, such as a blast, may create internal stress and deformation waves, which have shear and longitudinal components that can induce combined shear and compression of the brain tissue. To isolate the consequences of such interactions for the shear stress and to investigate the role of the extracellular fluid in the mechanical response, translational shear stretch at 10/s, 60/s, and 100/s translational shear rates under either 0% or 33% fixed transverse compression is applied without preconditioning to rat brain specimens. The specimens from the cerebrum, the cerebellum grey matter, and the brainstem white matter are nearly the full length of their respective regions. The translational shear stress response to translational shear deformation is characterized by the effect that each of four factors, high deformation rate, brain region, transverse compression, and specimen size, have on the shear stress magnitude averaged over ten specimens for each combination of factors. Increasing the deformation rate increases the magnitude of the shear stress at a given translational shear stretch, and as tested by ANOVAs so does applying transverse fixed compression of 33% of the thickness. The stress magnitude differs by the region that is the specimen source: cerebrum, cerebellum or brainstem. The magnitude of the shear stress response at a given deformation rate and stretch depends on the specimen length, called a specimen size effect. Surprisingly, under no compression a shorter length specimen requires more shear stress, but under 33% compression a shorter length specimen requires less shear stress, to meet a required shear deformation rate. The shear specimen size effect calls into question the applicability of the classical shear stress definition to hydrated soft biological tissue. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Stress Analysis of Boom of Special Mobile Crane for Plain Region in Transmission Line

    Science.gov (United States)

    Qin, Jian; Shao, Tao; Chen, Jun; Wan, Jiancheng; Li, Zhonghuan; Jiang, Ming

    2017-10-01

    Basis of the boom force analysis of special mobile crane for plain region in transmission line, the load type of boom design is confirmed. According to the different combinations of boom sections, the composite pattern of the different boom length is obtained to suit the actual conditions of boom overlapping. The large deformation model is employed with FEM to simulate the stress distribution of boom, and the calculation results are checked. The performance curves of rated load with different arm length and different working range are obtained, which ensures the lifting capacity of special mobile crane meeting the requirement of tower erection of transmission line. The proposed FEM of boom of mobile crane would provide certain guiding and reference to the boom design.

  4. Heat stress in cows at pasture and benefit of shade in a temperate climate region

    Science.gov (United States)

    Veissier, Isabelle; Van laer, Eva; Palme, Rupert; Moons, Christel P. H.; Ampe, Bart; Sonck, Bart; Andanson, Stéphane; Tuyttens, Frank A. M.

    2017-11-01

    Under temperate climates, cattle are often at pasture in summer and are not necessarily provided with shade. We aimed at evaluating in a temperate region (Belgium) to what extent cattle may suffer from heat stress (measured through body temperature, respiration rate and panting score, cortisol or its metabolites in milk, and feces on hot days) and at assessing the potential benefits of shade. During the summer of 2012, 20 cows were kept on pasture without access to shade. During the summer of 2011, ten cows had access to shade (young trees with shade cloth hung between them), whereas ten cows had no access. Climatic conditions were quantified by the Heat Load Index (HLI). In animals without access to shade respiration rates, panting scores, rectal temperatures, and milk cortisol concentrations increased as HLI increased in both 2011 and 2012. Fecal cortisol metabolites varied with HLI in 2011 only. When cattle had access to shade, their use of shade increased as the HLI increased. This effect was more pronounced during the last part of the summer, possibly due to better acquaintance with the shade construction. In this case, shade use increased to 65% at the highest HLI (79). Shade tempered the effects on respiration, rectal temperature, and fecal cortisol metabolites. Milk cortisol was not influenced by HLI for cows using shade for > 10% of the day. Therefore, even in temperate areas, cattle may suffer from heat when they are at pasture in summer and providing shade can reduce such stress.

  5. Clarifications on Continuous Renal Replacement Therapy and Hemodynamics.

    Science.gov (United States)

    Wang, Xiao-Ting; Wang, Cui; Zhang, Hong-Min; Liu, Da-Wei

    2017-05-20

    Continuous renal replacement therapy (CRRT) is a continuous process of bedside blood purification which is widely used in the treatment of acute kidney injury (AKI) and for fluid management. However, since AKI and fluid overload are often found to be associated with hemodynamic abnormalities, determining the relationship between CRRT and hemodynamics remains a challenge in the treatment of critically ill patients. The aim of this review was to summarize key points in the relationship between CRRT and hemodynamics and to understand and monitor renal hemodynamics in critically ill patients, especially those with AKI. This review was based on data in articles published in the PubMed databases up to January 30, 2017, with the following keywords: "continuous renal replacement therapy," "Hemodynamics," and "Acute kidney injury." Original articles and critical reviews on CRRT were selected for this review. CRRT might treat AKI by hemodynamic therapy, and it was an important form of hemodynamic therapy. The targets of hemodynamic therapy should be established when using CRRT. Therefore, hemodynamic management and stability were very important during CRRT. Most studies suggested that renal hemodynamics should be clearly identified. CRRT is not only a replacement for organ function, but an important form of hemodynamic therapy. Improved hemodynamic management of critically ill patients can be achieved by establishing specific therapeutic hemodynamic targets and maintaining circulatory stability during CRRT. Over the long term, observation of renal hemodynamics will provide greater opportunities for the progression of CRRT hemodynamic therapy.

  6. Stress- and structure-controlled anisotropy in a region of complex faulting—Yuha Desert, California

    Science.gov (United States)

    Cochran, Elizabeth S.; Kroll, Kayla A.

    2015-01-01

    We examine shear velocity anisotropy in the Yuha Desert, California using aftershocks of the 2010 M7.2 El Mayor-Cucapah earthquake. The Yuha Desert is underlain by a complex network of right- and left-lateral conjugate faults, some of which experienced triggered slip during the El Mayor-Cucapah earthquake. An automated method that implements multiple measurement windows and a range of bandpass filters is used to estimate the fast direction (ϕ) and delay time (δt) of the split shear waves. We find an average ϕ oriented approximately north–south suggesting it is primarily controlled by the regional maximum compressive stress direction. However, the spatial variability in ϕ reveals that the fault structures that underlie the Yuha Desert also influence the measured splitting parameters. We infer that the northeast- and northwest-oriented ϕ reflect shear fabric subparallel to the conjugate fault structures. We do not observe a simple correlation between δt and hypocentral distance. Instead, the observed spatial variation in δt suggests that near-source variation in anisotropic strength may be equal to or more important than effects local to the station. No temporal variation in splitting parameters is observed during the 70-day period following the main shock. In this region of complex faulting, we observe a spatially variable pattern of anisotropy that is both stress- and structure-controlled. This study suggests that shear fabric can form even along short, discontinuous fault strands with minimal offset.                   

  7. Region-Specific Vulnerability to Oxidative Stress, Neuroinflammation, and Tau Hyperphosphorylation in Experimental Diabetes Mellitus Mice.

    Science.gov (United States)

    Elahi, Montasir; Hasan, Zafrul; Motoi, Yumiko; Matsumoto, Shin-Ei; Ishiguro, Koichi; Hattori, Nobutaka

    2016-01-01

    Recent epidemiological evidence suggests that diabetes mellitus (DM) is a risk factor for Alzheimer's disease (AD). One of the pathological hallmarks of AD is hyperphosphorylated tau protein, which forms neurofibrillary tangles. Oxidative stress and the activation of inflammatory pathways are features that are associated with both DM and AD. However, the brain region specificity of AD-related neurodegeneration, which mainly occurs in the hippocampus while the cerebellum is relatively unaffected, has not yet been clarified. Therefore, we used experimental DM mice (caused by an intraperitoneal injection of streptozotocin [STZ]) to determine whether these neurodegeneration-associated mechanisms were associated with region-specific selective vulnerability or tau phosphorylation. The hippocampus, midbrain, and cerebellum of aged (14 to 18 months old) non-transgenic (NTg) and transgenic mice overexpressing wild-type human tau (Tg601 mice) were evaluated after a treatment with STZ. The STZ injection increased reactive oxygen species, lipid peroxidation markers such as 4-hydroxynonenal and malondialdehyde in the hippocampus, but not in the midbrain or cerebellum. The STZ treatment also increased the number of Iba-1-positive and CD68-positive microglial cells, astrocytes, and IL-1β, IL-6, IL-10, and IL-18 levels in the hippocampus, but not in the midbrain or cerebellum. Tau hyperphosphorylation was also enhanced in the hippocampus, but not in the midbrain or cerebellum. When the effects of STZ were compared between Tg601 and NTg mice, microglial proliferation and elevations in IL-6 and phosphorylated tau were higher in Tg601 mice. These results suggest that neuroinflammation and oxidative stress in STZ-treated mice are associated with tau hyperphosphorylation, which may contribute to selective neurodegeneration in human AD.

  8. Is stress perceived differently in relationships with parents and peers? Inter- and intra-regional comparisons on adolescents from 21 nations.

    Science.gov (United States)

    Persike, Malte; Seiffge-Krenke, Inge

    2014-06-01

    This study investigated how adolescents (mean age of 15 years) from 21 countries perceived parent- and peer-related stress. Across countries, adolescents perceived parent-related stress at considerably greater levels than peer-related stress. Adolescents assigned to six geographical regions differed significantly in overall stress levels as well as in the disparity between perceived stress levels in the parent and peer domain. Regional comparisons revealed that adolescents from Southern Europe exhibited the highest levels of parent-related stress, followed by adolescents from Latin America, the Middle East, and Asia. The stress levels of adolescents from Central European and North American countries were generally quite low. Correspondence analyses revealed distinctive patterns of perceived stress in close relationships, depending on the region. The discussion focuses on different parental styles and cultural values as potential influential factors for differences in stress perception between regions. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  9. The Serial Change of Cerebral Hemodynamics by Vascular Territory after Extracranial-Intracranial Bypass Surgery in Patients with Atherosclerosis of Cerebral Arteries

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Il Ki; Kim, Jae Seung; Ahn, Jae Sung; Kwon, Sun Uck; Im, Ki Chun; Lee, Jai Hyuen; Moon, Dae Hyuk [Asan Medial Center, Ulsan University School of Medicine, Seoul (Korea, Republic of)

    2008-02-15

    To assess the effect of extracranial-intracranial (EC-IC) bypass surgery on hemodynamic improvement, we evaluated serial regional cerebral hemodynamic change of the middle cerebral artery (MCA) in symptomatic patients with atherosclerotic occlusion of the internal carotid artery (ICA) or MCA using {sup 99m}Tc-ECD acetazolamide stress brain perfusion SPECT (Acetazolamide SPECT). The patients who had suffered a recent stroke with atherosclerotic ICA or MCA occlusion underwent EC-IC bypass surgery and Acetazolamide SPECT at 1 week before and three to six months after surgery. For image analysis, attenuation corrected images were spatially normalized to SPECT templates with SPM2. Anatomical automated labeling was applied to calculate mean counts of each Volume-Of-Interest (VOI). Seven VOIs of bilateral frontal, parietal, temporal regions of the MCA territory and the ipsilateral cerebellum were defined. Using mean counts of 7 VOIs, cerebral perfusion index and perfusion reserve index were calculated. Seventeen patients (M:F=12:5, mean age: 53{+-}2yr) were finally included in the analysis. The cerebral blood flow of the parietal region increased at 1 week (p=0.003) and decreased to the preoperative level at 3-6 months (p=0.003). The cerebrovascular reserve of the frontal and parietal regions increased significantly at 1 week after surgery (p<0.01) and improved further at 3-6 months. Cerebrovascular reserve of the MCA territory was significantly improved at early postoperative period after EC-IC bypass and kept improved state during long-term follow-up, although cerebral blood flow did not significantly improved. Therefore, cerebrovascular reserve may be a good indicator of postoperative hemodynamic improvement resulted from bypass effect.

  10. Hemodynamic characteristics of the vertebrobasilar system analyzed using MRI-based models.

    Science.gov (United States)

    Wake-Buck, Amanda K; Gatenby, J Christopher; Gore, John C

    2012-01-01

    The vertebrobasilar system (VBS) is unique in human anatomy in that two arteries merge into a single vessel, and it is especially important because it supplies the posterior circulation of the brain. Atherosclerosis develops in this region, and atherosclerotic plaques in the vertebrobasilar confluence can progress with catastrophic consequences, including artery occlusion. Quantitative assessments of the flow characteristics in the VBS could elucidate the factors that influence flow patterns in this confluence, and deviations from normal patterns might then be used to predict locations to monitor for potential pathological changes, to detect early signs of disease, and to evaluate treatment options and efficacy. In this study, high-field MRI was used in conjunction with computational fluid dynamics (CFD) modeling to investigate the hemodynamics of subject-specific confluence models (n = 5) and to identify different geometrical classes of vertebrobasilar systems (n = 12) of healthy adult subjects. The curvature of the vessels and their mutual orientation significantly affected flow parameters in the VBS. The basilar artery geometry strongly influenced both skewing of the velocity profiles and the wall shear stress distributions in the VBS. All five subjects modeled possessed varying degrees of vertebral asymmetry, and helical flow was observed in four cases, suggesting that factors other than vertebral asymmetry influence mixing of the vertebral artery flow contributions. These preliminary studies verify that quantitative, MR imaging techniques in conjunction with subject-specific CFD models of healthy adult subjects may be used to characterize VBS hemodynamics and to predict flow features that have been related to the initiation and development of atherosclerosis in large arteries. This work represents an important first step towards applying this approach to study disease initiation and progression in the VBS.

  11. Hemodynamic characteristics of the vertebrobasilar system analyzed using MRI-based models.

    Directory of Open Access Journals (Sweden)

    Amanda K Wake-Buck

    Full Text Available The vertebrobasilar system (VBS is unique in human anatomy in that two arteries merge into a single vessel, and it is especially important because it supplies the posterior circulation of the brain. Atherosclerosis develops in this region, and atherosclerotic plaques in the vertebrobasilar confluence can progress with catastrophic consequences, including artery occlusion. Quantitative assessments of the flow characteristics in the VBS could elucidate the factors that influence flow patterns in this confluence, and deviations from normal patterns might then be used to predict locations to monitor for potential pathological changes, to detect early signs of disease, and to evaluate treatment options and efficacy. In this study, high-field MRI was used in conjunction with computational fluid dynamics (CFD modeling to investigate the hemodynamics of subject-specific confluence models (n = 5 and to identify different geometrical classes of vertebrobasilar systems (n = 12 of healthy adult subjects. The curvature of the vessels and their mutual orientation significantly affected flow parameters in the VBS. The basilar artery geometry strongly influenced both skewing of the velocity profiles and the wall shear stress distributions in the VBS. All five subjects modeled possessed varying degrees of vertebral asymmetry, and helical flow was observed in four cases, suggesting that factors other than vertebral asymmetry influence mixing of the vertebral artery flow contributions. These preliminary studies verify that quantitative, MR imaging techniques in conjunction with subject-specific CFD models of healthy adult subjects may be used to characterize VBS hemodynamics and to predict flow features that have been related to the initiation and development of atherosclerosis in large arteries. This work represents an important first step towards applying this approach to study disease initiation and progression in the VBS.

  12. Stress induced a shift from dorsal hippocampus to prefrontal cortex-dependent memory retrieval: role of regional corticosterone.

    OpenAIRE

    Gaelle eDominguez; Pierre eFaucher; Nadia eHenkous; Ali eKrazem; Christophe ePierard; Daniel eBeracochea

    2014-01-01

    Most of the deleterious effects of stress on memory retrieval are due to a dysfunction of the hippocampo-prefrontal cortex interplay. The role of the stress-induced regional corticosterone increase in such dysfunction remains however unclear, since there is no published study as yet dedicated to measuring corticosterone concentrations simultaneously in both the prefrontal cortex (mPFC) and the hippocampus (dHPC) in relation with memory impairments. To that aim, we first showed in Experiment 1...

  13. Biomechanics of Ergometric Stress Test: regional and local effects on elastic, transitional and muscular human arteries

    Science.gov (United States)

    Valls, G.; Torrado, J.; Farro, I.; Bia, D.; Zócalo, Y.; Lluberas, S.; Craiem, D.; Armentano, Rl

    2011-09-01

    Ergometric exercise stress tests (EST) give important information about the cardiovascular (CV) response to increased demands. The expected EST-related changes in variables like blood pressure and heart rate are known, but those in the arterial biomechanics are controversial and incompletely characterized. In this context, this work aims were to characterize the regional and local arterial biomechanical behaviour in response to EST; to evaluate its temporal profile in the post-EST recovery phase; and to compare the biomechanical response of different to EST. Methods: In 16 non-trained healthy young subjects the carotid-femoral pulse wave velocity and the carotid, femoral and brachial arterial distensibility were non-invasively evaluated before (Rest) and after EST. Main results: The EST resulted in an early increase in the arterial stiffness, evidenced by both, regional and local parameters (pulse wave velocity increase and distensibility reduction). When analyzing conjunctly the different post-EST recovery stages there were quali-quantitative differences among the arterial local stiffness response to EST. The biomechanical changes could not be explained only by blood pressure variations.

  14. The Interaction between Fluid Wall Shear Stress and Solid Circumferential Strain Affects Endothelial Gene Expression

    Science.gov (United States)

    Amaya, Ronny; Pierides, Alexis; Tarbell, John M.

    2015-01-01

    Endothelial cells lining the walls of blood vessels are exposed simultaneously to wall shear stress (WSS) and circumferential stress (CS) that can be characterized by the temporal phase angle between WSS and CS (stress phase angle – SPA). Regions of the circulation with highly asynchronous hemodynamics (SPA close to -180°) such as coronary arteries are associated with the development of pathological conditions such as atherosclerosis and intimal hyperplasia whereas more synchronous regions (SPA closer to 0°) are spared of disease. The present study evaluates endothelial cell gene expression of 42 atherosclerosis-related genes under asynchronous hemodynamics (SPA=-180 °) and synchronous hemodynamics (SPA=0 °). This study used a novel bioreactor to investigate the cellular response of bovine aortic endothelial cells (BAECS) exposed to a combination of pulsatile WSS and CS at SPA=0 or SPA=-180. Using a PCR array of 42 genes, we determined that BAECS exposed to non-reversing sinusoidal WSS (10±10 dyne/cm2) and CS (4 ± 4 %) over a 7 hour testing period displayed 17 genes that were up regulated by SPA = -180 °, most of them pro-atherogenic, including NFκB and other NFκB target genes. The up regulation of NFκB p50/p105 and p65 by SPA =-180° was confirmed by Western blots and immunofluorescence staining demonstrating the nuclear translocation of NFκB p50/p105 and p65. These data suggest that asynchronous hemodynamics (SPA=-180 °) can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA may be an important parameter characterizing arterial susceptibility to disease. PMID:26147292

  15. The Interaction between Fluid Wall Shear Stress and Solid Circumferential Strain Affects Endothelial Gene Expression.

    Directory of Open Access Journals (Sweden)

    Ronny Amaya

    Full Text Available Endothelial cells lining the walls of blood vessels are exposed simultaneously to wall shear stress (WSS and circumferential stress (CS that can be characterized by the temporal phase angle between WSS and CS (stress phase angle - SPA. Regions of the circulation with highly asynchronous hemodynamics (SPA close to -180° such as coronary arteries are associated with the development of pathological conditions such as atherosclerosis and intimal hyperplasia whereas more synchronous regions (SPA closer to 0° are spared of disease. The present study evaluates endothelial cell gene expression of 42 atherosclerosis-related genes under asynchronous hemodynamics (SPA=-180 ° and synchronous hemodynamics (SPA=0 °. This study used a novel bioreactor to investigate the cellular response of bovine aortic endothelial cells (BAECS exposed to a combination of pulsatile WSS and CS at SPA=0 or SPA=-180. Using a PCR array of 42 genes, we determined that BAECS exposed to non-reversing sinusoidal WSS (10±10 dyne/cm2 and CS (4 ± 4% over a 7 hour testing period displayed 17 genes that were up regulated by SPA = -180 °, most of them pro-atherogenic, including NFκB and other NFκB target genes. The up regulation of NFκB p50/p105 and p65 by SPA =-180° was confirmed by Western blots and immunofluorescence staining demonstrating the nuclear translocation of NFκB p50/p105 and p65. These data suggest that asynchronous hemodynamics (SPA=-180 ° can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA may be an important parameter characterizing arterial susceptibility to disease.

  16. Diabetes and stress: an anthropological review for study of modernizing populations in the US-Mexico border region.

    Science.gov (United States)

    Ely, John J; Zavaskis, Tony; Wilson, Susan L

    2011-01-01

    Diabetes is a growing worldwide problem, characterized by considerable ethnic variation and being particularly common in modernizing populations. Modernization is accompanied by a variety of stressful sociocultural changes that are believed to increase the risk of diabetes. Unfortunately, there is little accurate knowledge about impact of stress on the risk of diabetes in the US-Mexico border area. Literature searches were performed in PubMed and Google Scholar to identify anthropological studies on stress and diabetes. Snowball and opportunistic sampling were used to expand the identified literature. In total, 30 anthropological studies were identified concerning the role of stress and modernization on diabetes among Indigenous peoples. This article reviews the available information regarding stress and diabetes in different populations from various anthropological perspectives. Four different concepts of stress were indentified: physiological, psychological, psychosocial and nutritional stress. Unlike physiological and nutritional theories of diabetes, psychological and psychosocial theories of stress and disease lack etiological specificity. No study addressed all four concepts of stress and few studies addressed more than two concepts. Most studies concerned nutritional stress and the developmental origins of diabetes. Most studies were conducted on the Pima Indians of Arizona and Mexico. All four stress concepts have some evidence as determinants of diabetes. These theoretical concepts and ethnographic results can provide the basis for developing comprehensive research protocols and public health intervention targeted at diabetes. A comprehensive view of stress can potentially explain the high prevalence of diabetes in developing countries and among Indigenous peoples. These results can be used to inform public health interventions aimed at reducing diabetes in the US-Mexico border region or similar areas, help identify at-risk individuals, and guide health

  17. Hemodynamics and Mechanobiology of Aortic Valve Inflammation and Calcification

    Directory of Open Access Journals (Sweden)

    Kartik Balachandran

    2011-01-01

    Full Text Available Cardiac valves function in a mechanically complex environment, opening and closing close to a billion times during the average human lifetime, experiencing transvalvular pressures and pulsatile and oscillatory shear stresses, as well as bending and axial stress. Although valves were originally thought to be passive pieces of tissue, recent evidence points to an intimate interplay between the hemodynamic environment and biological response of the valve. Several decades of study have been devoted to understanding these varied mechanical stimuli and how they might induce valve pathology. Here, we review efforts taken in understanding the valvular response to its mechanical milieu and key insights gained from in vitro and ex vivo whole-tissue studies in the mechanobiology of aortic valve remodeling, inflammation, and calcification.

  18. Hemodynamics of Stent Implantation Procedures in Coronary Bifurcations: an in vitro study

    CERN Document Server

    Brindise, Melissa C; Burzotta, Francesco; Migliavacca, Francesco; Vlachos, Pavlos P

    2016-01-01

    Stent implantation in coronary bifurcations presents unique challenges and currently there is no universally accepted stent deployment approach. Despite clinical and computational studies, to date, the effect of each stent implantation method on the coronary artery hemodynamics is not well understood. In this study the hemodynamics of stented coronary bifurcations under pulsatile flow conditions were investigated experimentally. Three implantation methods, provisional side branch (PSB), culotte (CUL), and crush (CRU), were investigated using time-resolved particle image velocimetry (PIV) to measure the velocity fields. Subsequently, hemodynamic parameters including wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated and the pressure field through the vessel was non-invasively quantified. The effects of each stented case were evaluated and compared against an un-stented case. CRU provided the lowest compliance mismatch, but demonstrated detrimental stent in...

  19. CFD Modelling of Local Hemodynamics in Intracranial Aneurysms Harboring Arterial Branches.

    Science.gov (United States)

    Krylov, Vladimir; Grigoryeva, Elena; Dolotova, Daria; Blagosklonova, Evgenia; Gavrilov, Andrey

    2017-01-01

    The main cause of non-traumatic subarachnoid haemorrhage is an intracranial aneurysm's rupture. The choice of treatment approach is exceptionally difficult in cases of aneurysms with additional branches on the aneurysm's dome or neck. The impact of the arterial branches on local hemodynamics is still unclear and controversial question. At the same time, up-to-date methods of image processing and mathematical modeling provide a way to investigate the hemodynamic environment of aneurysms. The paper discusses hemodynamic aspects of aneurysms harboring arterial branch through the use of patient-specific 3D models and computational fluid dynamics (CFD) methods. The analysis showed that the presence of the arterial branches has a great influence on flow streamlines and wall shear stress, particularly for side wall aneurysm.

  20. A sliding mode observer for hemodynamic characterization under modeling uncertainties

    KAUST Repository

    Zayane, Chadia

    2014-06-01

    This paper addresses the case of physiological states reconstruction in a small region of the brain under modeling uncertainties. The misunderstood coupling between the cerebral blood volume and the oxygen extraction fraction has lead to a partial knowledge of the so-called balloon model describing the hemodynamic behavior of the brain. To overcome this difficulty, a High Order Sliding Mode observer is applied to the balloon system, where the unknown coupling is considered as an internal perturbation. The effectiveness of the proposed method is illustrated through a set of synthetic data that mimic fMRI experiments.

  1. Combined Effects of Flow Diverting Strategies and Parent Artery Curvature on Aneurysmal Hemodynamics: A CFD Study.

    Science.gov (United States)

    Xu, Jinyu; Wu, Zhichen; Yu, Ying; Lv, Nan; Wang, Shengzhang; Karmonik, Christof; Liu, Jian-Min; Huang, Qinghai

    2015-01-01

    Flow diverters (FD) are increasingly being considered for treating large or giant wide-neck aneurysms. Clinical outcome is highly variable and depends on the type of aneurysm, the flow diverting device and treatment strategies. The objective of this study was to analyze the effect of different flow diverting strategies together with parent artery curvature variations on altering intra-aneurysmal hemodynamics. Four ideal intracranial aneurysm models with different parent artery curvature were constructed. Computational fluid dynamics (CFD) simulations of the hemodynamics before and after applying five types of flow diverting strategies (single FD, single FD with 5% and 10% packing density of coils, two FDs with 25% and 50% overlapping rate) were performed. Changes in pressure, wall shear stress (WSS), relative residence time (RRT), inflow velocity and inflow volume rate were calculated and compared. Each flow diverting strategy resulted in enhancement of RRT and reduction of normalized mean WSS, inflow volume rate and inflow velocity in various levels. Among them, 50% overlapped FD induced most effective hemodynamic changes in RRT and inflow volume rate. The mean pressure only slightly decreased after treatment. Regardless of the kind of implantation of FD, the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased. Of all flow diverting strategies, overlapping FDs induced most favorable hemodynamic changes. Hemodynamics alterations post treatment were substantially influenced by parent artery curvature. Our results indicate the need of an individualized flow diverting strategy that is tailored for a specific aneurysm.

  2. Large Negative Stress Phase Angle (SPA) attenuates nitric oxide production in bovine aortic endothelial cells.

    Science.gov (United States)

    Dancu, Michael B; Tarbell, John M

    2006-06-01

    Hemodynamics plays an important role in cardiovascular physiology and pathology. Pulsatile flow (Q), pressure (P), and diameter (D) waveforms exert wall shear stress (WSS), normal stress, and circumferential strain (CS) on blood vessels. Most in vitro studies to date have focused on either WSS or CS but not their interaction. Recently, we have shown that concomitant WSS and CS affect EC biochemical response modulated by the temporal phase angle between WSS and CS (stress phase angle, SPA). Large negative SPA has been shown to occur in regions of the circulation where atherosclerosis and intimal hyperplasia are prevalent. Here, we report that nitric oxide (NO) biochemical secretion was significantly decreased in response to a large negative SPA of -180 deg with respect to an SPA of 0 degrees in bovine aortic endothelial cells (BAEC) at 5 h. A new hemodynamic simulator for the study of the physiologic SPA was used to provide the hemodynamic conditions of pro-atherogenic (SPA = -180 deg) and normopathic (SPA = 0 deg) states. The role of complex hemodynamics in vascular remodeling, homeostasis, and pathogenesis can be advanced by further assessment of the hypothesis that a large negative SPA is pro-atherogenic.

  3. Water Stress & Biomass Monitoring and SWAP Modeling of Irrigated Crops in Saratov Region of Russia

    Science.gov (United States)

    Zeyliger, Anatoly; Ermolaeva, Olga

    2016-04-01

    results of analyzing water stress during growing season of 2012 and yielded biomass of crops three types of crops alfalfa, corn and soya irrigated by sprinkling machines at left bank of Volga River at Saratov Region of Russia are presented and analyzed. For that a combination of data received from satellite, local meteorological station and farmers as well as SWAP model was used. Analyze of data sets of monitored water deficit of each crop averaged for irrigation period was done by linear regression with yielded biomass values. Following analyze of effectiveness of irrigation water application was done by SWAP agrohydrological model.

  4. Stress induced a shift from dorsal hippocampus to prefrontal cortex-dependent memory retrieval: role of regional corticosterone.

    Directory of Open Access Journals (Sweden)

    Gaelle eDominguez

    2014-05-01

    Full Text Available Most of the deleterious effects of stress on memory retrieval are due to a dysfunction of the hippocampo-prefrontal cortex interplay. The role of the stress-induced regional corticosterone increase in such dysfunction remains however unclear, since there is no published study as yet dedicated to measuring corticosterone concentrations simultaneously in both the prefrontal cortex (mPFC and the hippocampus (dHPC in relation with memory impairments. To that aim, we first showed in Experiment 1 that an acute stress (3 electric footschocks; 0.9 mA each delivered before memory testing reversed the memory retrieval pattern (MRP in a serial discrimination task in which mice learned two successive discriminations. More precisely, whereas non-stressed animals remembered accurately the first learned discrimination and not the second one, stressed mice remembered more accurately the second discrimination but not the first one. We demonstrated that local inactivation of dHPC or mPFC with the anesthetic lidocaine recruited the dHPC activity in non-stress conditions whereas the stress-induced MRP inversion recruited the mPFC activity. In a second experiment, we showed that acute stress induced a very similar time-course evolution of corticosterone rises within both the mPFC and dHPC. In a 3rd experiment, we found however that in situ injections of corticosterone either within the mPFC or the dHPC before memory testing favored the emergence of the mPFC-dependent MRP but blocked the emergence of the dHPC-dependent one. Overall, our study evidences that the simultaneous increase of corticosterone after stress in both areas induces a shift from dHPC (non stress condition to mPFC-dependent memory retrieval pattern and that corticosterone is critically involved in mediating the deleterious effects of stress on cognitive functions involving the mPFC-HPC interplay.

  5. Stress induced a shift from dorsal hippocampus to prefrontal cortex dependent memory retrieval: role of regional corticosterone.

    Science.gov (United States)

    Dominguez, Gaelle; Faucher, Pierre; Henkous, Nadia; Krazem, Ali; Piérard, Christophe; Béracochéa, Daniel

    2014-01-01

    Most of the deleterious effects of stress on memory retrieval are due to a dysfunction of the hippocampo-prefrontal cortex interplay. The role of the stress-induced regional corticosterone increase in such dysfunction remains however unclear, since there is no published study as yet dedicated to measuring corticosterone concentrations simultaneously in both the prefrontal cortex (mPFC) and the hippocampus (dHPC) in relation with memory impairments. To that aim, we first showed in Experiment 1 that an acute stress (3 electric footschocks; 0.9 mA each) delivered before memory testing reversed the memory retrieval pattern (MRP) in a serial discrimination task in which mice learned two successive discriminations. More precisely, whereas non-stressed animals remembered accurately the first learned discrimination and not the second one, stressed mice remembered more accurately the second discrimination but not the first one. We demonstrated that local inactivation of dHPC or mPFC with the anesthetic lidocaine recruited the dHPC activity in non-stress conditions whereas the stress-induced MRP inversion recruited the mPFC activity. In a second experiment, we showed that acute stress induced a very similar time-course evolution of corticosterone rises within both the mPFC and dHPC. In a 3rd experiment, we found however that in situ injections of corticosterone either within the mPFC or the dHPC before memory testing favored the emergence of the mPFC-dependent MRP but blocked the emergence of the dHPC-dependent one. Overall, our study evidences that the simultaneous increase of corticosterone after stress in both areas induces a shift from dHPC (non-stress condition) to mPFC-dependent MRP and that corticosterone is critically involved in mediating the deleterious effects of stress on cognitive functions involving the mPFC-HPC interplay.

  6. Frost stress evolution and winter pea ideotype in the context of climate warming at a regional scale

    OpenAIRE

    Castel Thierry; Lecomte Christophe; Richard Yves; Lejeune-Hénaut Isabelle; Larmure Annabelle

    2017-01-01

    Pea (Pisum sativum L.) is an important crop in temperate regions for its high seed protein concentration that is particularly sensitive to abiotic stresses. The abrupt temperature increase known as the “1987/1988 temperature regime shift” that occurs over Europe is questioning how winter pea will perform in the changing climate. This study assessed the winter frost damage evolution along from 1961 to 2015 in Burgundy-Franche-Comté by using: (1) daily observed and gridded regional temperature ...

  7. The extent and causes of stress in teachers in the George region ...

    African Journals Online (AJOL)

    Stress is currently a phenomenon that must be recognized and addressed in various professions and the teaching profession is no exception. Stress in the workplace can cause "job compassion fatigue". In the past teachers did not consider stress to be the primary cause when they needed to escape from the school ...

  8. Otoacoustic emissions and biomarkers of oxidative stress in students of a tobacco-producing region.

    Science.gov (United States)

    Kunst, Letícia Regina; Garcia, Michele Vargas; Machado, Alencar Kolinski; Barbisan, Fernanda; Silveira, Aron Ferreira da

    2014-01-01

    To verify the association between the amplitude of distortion-product otoacoustic emissions (DPOAE) and biomarkers of oxidative stress (OS) in resident students of the tobacco-producing region. Participated in the study group (SG) 21 normal-hearing students from the tobacco-producing region, and in the control group (CG) 25 normal-hearing students who did not live in the countryside. The auditory system was assessed by DPOAE and the following biomarkers: dichlorofluorescein diacetate (DCFH-DA) and micronucleus test (MN). Both groups showed DPOAE present in both ears. Significant difference was detected between groups--in the right ear in the frequency of 4.000 Hz and in the left ear in the frequency of 2.000 Hz--with the mean amplitude of the DPOAE of the SG lower than the one found in the CG. Considering both ears, the SG presented lower mean across all frequencies and it was found a significant difference in the frequencies of 2.000 and 4.000 Hz. The overall mean of DPOAE, by ear, no significant differences were observed. In relation to the rate of production of free radicals, the mean of the SG was significantly higher than that of the mean of the CG. For the frequency of abnormal cells in the MN test, the mean of the SG was also considerate significantly higher than the mean of the CG. The SG showed a lower response level of DPOAE at all frequencies and high levels of biomarkers of EO, however there was no association between assessments.

  9. Age and Vascular Burden Determinants of Cortical Hemodynamics Underlying Verbal Fluency.

    Directory of Open Access Journals (Sweden)

    Sebastian Heinzel

    Full Text Available Aging processes and several vascular burden factors have been shown to increase the risk of dementia including Alzheimer's disease. While pathological alterations in dementia precede diagnosis by many years, reorganization of brain processing might temporarily delay cognitive decline. We hypothesized that in healthy elderly individuals both age-related neural and vascular factors known to be related to the development of dementia impact functional cortical hemodynamics during increased cognitive demands.Vascular burden factors and cortical functional hemodynamics during verbal fluency were assessed in 1052 non-demented elderly individuals (51 to 83 years; cross-sectional data of the longitudinal TREND study using functional near-infrared spectroscopy (fNIRS. The prediction of functional hemodynamic responses by age in multiple regressions and the impact of single and cumulative vascular burden factors including hypertension, diabetes, obesity, smoking and atherosclerosis were investigated.Replicating and extending previous findings we could show that increasing age predicted functional hemodynamics to be increased in right prefrontal and bilateral parietal cortex, and decreased in bilateral inferior frontal junction during phonological fluency. Cumulative vascular burden factors, with hypertension in particular, decreased left inferior frontal junction hemodynamic responses during phonological fluency. However, age and vascular burden factors showed no statistical interaction on functional hemodynamics.Based on these findings, one might hypothesize that increased fronto-parietal processing may represent age-related compensatory reorganization during increased cognitive demands. Vascular burden factors, such as hypertension, may contribute to regional cerebral hypoperfusion. These neural and vascular hemodynamic determinants should be investigated longitudinally and combined with other markers to advance the prediction of future cognitive decline

  10. [Hemodynamic evaluation of the patient with microvarices].

    Science.gov (United States)

    Alvarez Sánchez, J A; Vega Gómez, M E; Rodríguez Lacaba, B; Martínez Griñán, M A

    1992-01-01

    The present study included 21 lower limbs with micro varicosities, 56 lower limbs with retrograde flow-varicosities (positive Rivlin) and 35 health lower limbs. Technics used for diagnosis were: Doppler ultrasonography and strain gauge plethysmography. We found a higher incidence of valvular failure on the varicose patients with retrograde flow (showing changes on their viscoelastic features of their venous walls). On the contrary, patient with microvaricosities showed an hemodynamics similar to the healty patient: we did not found any difference on the variables analyzed between the two groups. We conclude that the presence of microvaricosities has no influence on the analyzed hemodynamic parametres.

  11. Learning, Adjustment and Stress Disorders: With Special Reference to Tsunami Affected Regions. Beitrage zur Padagogischen und Rehabilitationspsychologie. Volume 1

    Science.gov (United States)

    Witruk, Evelin, Ed.; Riha, David, Ed.; Teichert, Alexandra, Ed.; Haase, Norman, Ed.; Stueck, Marcus, Ed.

    2010-01-01

    This book contains selected contributions from the international workshop Learning, "Adjustment and Stress Disorders--with special reference to Tsunami affected Regions" organised by Evelin Witruk and the team of Educational and Rehabilitative Psychology at the University of Leipzig in January 2006. The book contains new results and the…

  12. Thinner regions of intracranial aneurysm wall correlate with regions of higher wall shear stress: a 7.0 tesla MRI

    Science.gov (United States)

    Blankena, Roos; Kleinloog, Rachel; Verweij, Bon H.; van Ooij, Pim; ten Haken, Bennie; Luijten, Peter R.; Rinkel, Gabriel J.E.; Zwanenburg, Jaco J.M.

    2016-01-01

    Purpose To develop a method for semi-quantitative wall thickness assessment on in vivo 7.0 tesla (7T) MRI images of intracranial aneurysms for studying the relation between apparent aneurysm wall thickness and wall shear stress. Materials and Methods Wall thickness was analyzed in 11 unruptured aneurysms in 9 patients, who underwent 7T MRI with a TSE based vessel wall sequence (0.8 mm isotropic resolution). A custom analysis program determined the in vivo aneurysm wall intensities, which were normalized to signal of nearby brain tissue and were used as measure for apparent wall thickness (AWT). Spatial wall thickness variation was determined as the interquartile range in AWT (the middle 50% of the AWT range). Wall shear stress was determined using phase contrast MRI (0.5 mm isotropic resolution). We performed visual and statistical comparisons (Pearson’s correlation) to study the relation between wall thickness and wall shear stress. Results 3D colored AWT maps of the aneurysms showed spatial AWT variation, which ranged from 0.07 to 0.53, with a mean variation of 0.22 (a variation of 1.0 roughly means a wall thickness variation of one voxel (0.8mm)). In all aneurysms, AWT was inversely related to WSS (mean correlation coefficient −0.35, P<0.05). Conclusions A method was developed to measure the wall thickness semi-quantitatively, using 7T MRI. An inverse correlation between wall shear stress and AWT was determined. In future studies, this non-invasive method can be used to assess spatial wall thickness variation in relation to pathophysiologic processes such as aneurysm growth and –rupture. PMID:26892986

  13. Nicotine Modulates Multiple Regions in the Limbic Stress Network Regulating Activation of Hypophysiotrophic Neurons in Hypothalamic Paraventricular Nucleus

    Science.gov (United States)

    Yu, Guoliang; Sharp, Burt M.

    2012-01-01

    Nicotine intake affects CNS responses to stressors. We reported that nicotine self-administration (SA) augmented the hypothalamo-pituitary-adrenal (HPA) stress response, in part due to altered neurotransmission and neuropeptide expression within hypothalamic paraventricular nucleus (PVN). Limbic-PVN interactions involving medial prefrontal cortex, amygdala, bed nucleus of the stria terminalis (BST) greatly impact the HPA stress response. Therefore, we investigated the effects of nicotine SA on stress-induced neuronal activation in limbic-PVN network, using c-Fos protein immunohistochemistry and retrograde tracing. Nicotine decreased stress-induced c-Fos in prelimbic cortex (PrL), anteroventral BST (avBST), and peri-PVN; but increased c-Fos induction in medial amygdala (MeA), locus coeruleus, and PVN. Fluoro-gold (FG) was injected into avBST or PVN, since GABAergic neurons in avBST projecting to PVN corticotrophin-releasing factor (CRF) neurons relay information from both PrL glutamatergic and MeA GABAergic neurons. The stress-induced c-Fos expression in retrograde-labeled FG+ neurons was decreased in PrL by nicotine, but increased in MeA, and also reduced in avBST. Therefore, within limbic-PVN network, nicotine SA exerts selective regional effects on neuronal activation by stress. These findings expand the mechanistic framework by demonstrating altered limbic-BST-PVN interactions underlying the disinhibition of PVN CRF neurons, an essential component of the amplified HPA response to stress by nicotine. PMID:22578217

  14. Acute stress evokes sexually dimorphic, stressor-specific patterns of neural activation across multiple limbic brain regions in adult rats.

    Science.gov (United States)

    Sood, Ankit; Chaudhari, Karina; Vaidya, Vidita A

    2018-03-01

    Stress enhances the risk for psychiatric disorders such as anxiety and depression. Stress responses vary across sex and may underlie the heightened vulnerability to psychopathology in females. Here, we examined the influence of acute immobilization stress (AIS) and a two-day short-term forced swim stress (FS) on neural activation in multiple cortical and subcortical brain regions, implicated as targets of stress and in the regulation of neuroendocrine stress responses, in male and female rats using Fos as a neural activity marker. AIS evoked a sex-dependent pattern of neural activation within the cingulate and infralimbic subdivisions of the medial prefrontal cortex (mPFC), lateral septum (LS), habenula, and hippocampal subfields. The degree of neural activation in the mPFC, LS, and habenula was higher in males. Female rats exhibited reduced Fos positive cell numbers in the dentate gyrus hippocampal subfield, an effect not observed in males. We addressed whether the sexually dimorphic neural activation pattern noted following AIS was also observed with the short-term stress of FS. In the paraventricular nucleus of the hypothalamus and the amygdala, FS similar to AIS resulted in robust increases in neural activation in both sexes. The pattern of neural activation evoked by FS was distinct across sexes, with a heightened neural activation noted in the prelimbic mPFC subdivision and hippocampal subfields in females and differed from the pattern noted with AIS. This indicates that the sex differences in neural activation patterns observed within stress-responsive brain regions are dependent on the nature of stressor experience.

  15. Bioimpedance Measurement of Segmental Fluid Volumes and Hemodynamics

    Science.gov (United States)

    Montgomery, Leslie D.; Wu, Yi-Chang; Ku, Yu-Tsuan E.; Gerth, Wayne A.; DeVincenzi, D. (Technical Monitor)

    2000-01-01

    Bioimpedance has become a useful tool to measure changes in body fluid compartment volumes. An Electrical Impedance Spectroscopic (EIS) system is described that extends the capabilities of conventional fixed frequency impedance plethysmographic (IPG) methods to allow examination of the redistribution of fluids between the intracellular and extracellular compartments of body segments. The combination of EIS and IPG techniques was evaluated in the human calf, thigh, and torso segments of eight healthy men during 90 minutes of six degree head-down tilt (HDT). After 90 minutes HDT the calf and thigh segments significantly (P < 0.05) lost conductive volume (eight and four percent, respectively) while the torso significantly (P < 0.05) gained volume (approximately three percent). Hemodynamic responses calculated from pulsatile IPG data also showed a segmental pattern consistent with vascular fluid loss from the lower extremities and vascular engorgement in the torso. Lumped-parameter equivalent circuit analyses of EIS data for the calf and thigh indicated that the overall volume decreases in these segments arose from reduced extracellular volume that was not completely balanced by increased intracellular volume. The combined use of IPG and EIS techniques enables noninvasive tracking of multi-segment volumetric and hemodynamic responses to environmental and physiological stresses.

  16. The role of death-associated protein kinase in endothelial apoptosis under fluid shear stress

    OpenAIRE

    Rennier, Keith R

    2015-01-01

    Endothelial cells are the interface between hemodynamic fluid flow and vascular tissue contact. They actively translate physical and chemical stimuli into intracellular signaling cascades which in turn regulate cell function, and endothelial dysfunction leads to inflammation and diseased conditions. For example, atherosclerosis, a chronic vascular disease, favorably develops in regions of disturbed fluid flow and low shear stress. Apoptosis, or programmed cell death, must be properly regulate...

  17. Stress transfer to the Denali and other regional faults from the M 9.2 Alaska earthquake of 1964

    Science.gov (United States)

    Bufe, C.G.

    2004-01-01

    Stress transfer from the great 1964 Prince William Sound earthquake is modeled on the Denali fault, including the Denali-Totschunda fault segments that ruptured in 2002, and on other regional fault systems where M 7.5 and larger earthquakes have occurred since 1900. The results indicate that analysis of Coulomb stress transfer from the dominant earthquake in a region is a potentially powerful tool in assessing time-varying earthquake hazard. Modeled Coulomb stress increases on the northern Denali and Totschunda faults from the great 1964 earthquake coincide with zones that ruptured in the 2002 Denali fault earthquake, although stress on the Susitna Glacier thrust plane, where the 2002 event initiated, was decreased. A southeasterlytrending Coulomb stress transect along the right-lateral Totschunda-Fairweather-Queen Charlotte trend shows stress transfer from the 1964 event advancing slip on the Totschunda, Fairweather, and Queen Charlotte segments, including the southern Fairweather segment that ruptured in 1972. Stress transfer retarding right-lateral strike slip was observed from the southern part of the Totschunda fault to the northern end of the Fairweather fault (1958 rupture). This region encompasses a gap with shallow thrust faulting but with little evidence of strike-slip faulting connecting the segments to the northwest and southeast. Stress transfer toward failure was computed on the north-south trending right-lateral strike-slip faults in the Gulf of Alaska that ruptured in 1987 and 1988, with inhibitory stress changes at the northern end of the northernmost (1987) rupture. The northern Denali and Totschunda faults, including the zones that ruptured in the 2002 earthquakes, follow very closely (within 3%), for about 90??, an arc of a circle of radius 375 km. The center of this circle is within a few kilometers of the intersection at depth of the Patton Bay fault with the Alaskan megathrust. This inferred asperity edge may be the pole of counterclockwise

  18. Calibrated MRI to evaluate cerebral hemodynamics in patients with an internal carotid artery occlusion

    NARCIS (Netherlands)

    Vis, J.B. De; Petersen, E.T.; Bhogal, A.; Hartkamp, N.S.; Klijn, C.J.M.; Kappelle, L.J.; Hendrikse, J.

    2015-01-01

    The purpose of this study was to assess whether calibrated magnetic resonance imaging (MRI) can identify regional variances in cerebral hemodynamics caused by vascular disease. For this, arterial spin labeling (ASL)/blood oxygen level-dependent (BOLD) MRI was performed in 11 patients (65+/-7 years)

  19. Regional and national differences in stressful life events: The role of cultural factors, economic development, and gender.

    Science.gov (United States)

    Vázquez, José Juan; Panadero, Sonia; Martín, Rosa M

    2015-07-01

    The study analyzed differences in the risk of experiencing stressful life events (SLE) according to cultural factors, the level of economic development of the region inhabited, and gender. Information was gathered on the number and nature of SLE experienced by a sample of 604 undergraduates from 3 regions with very different levels of economic development: Madrid (Spain), León (Nicaragua), and Bilwi (Nicaragua). The results indicated a greater risk of experiencing SLE among undergraduates from Nicaragua, but few differences attributed to the undergraduates' gender or the level of economic development in the region they inhabit within the same country. (c) 2015 APA, all rights reserved).

  20. The Campylobacter jejuni Oxidative Stress Regulator RrpB Is Associated with a Genomic Hypervariable Region and Altered Oxidative Stress Resistance

    Science.gov (United States)

    Gundogdu, Ozan; da Silva, Daiani T.; Mohammad, Banaz; Elmi, Abdi; Wren, Brendan W.; van Vliet, Arnoud H. M.; Dorrell, Nick

    2016-01-01

    Campylobacter jejuni is the leading cause of bacterial foodborne diarrhoeal disease worldwide. Despite the microaerophilic nature of the bacterium, C. jejuni can survive the atmospheric oxygen conditions in the environment. Bacteria that can survive either within a host or in the environment like C. jejuni require variable responses to survive the stresses associated with exposure to different levels of reactive oxygen species. The MarR-type transcriptional regulators RrpA and RrpB have recently been shown to play a role in controlling both the C. jejuni oxidative and aerobic stress responses. Analysis of 3,746 C. jejuni and 486 C. coli genome sequences showed that whilst rrpA is present in over 99% of C. jejuni strains, the presence of rrpB is restricted and appears to correlate with specific MLST clonal complexes (predominantly ST-21 and ST-61). C. coli strains in contrast lack both rrpA and rrpB. In C. jejuni rrpB+ strains, the rrpB gene is located within a variable genomic region containing the IF subtype of the type I Restriction-Modification (hsd) system, whilst this variable genomic region in C. jejuni rrpB- strains contains the IAB subtype hsd system and not the rrpB gene. C. jejuni rrpB- strains exhibit greater resistance to peroxide and aerobic stress than C. jejuni rrpB+ strains. Inactivation of rrpA resulted in increased sensitivity to peroxide stress in rrpB+ strains, but not in rrpB- strains. Mutation of rrpA resulted in reduced killing of Galleria mellonella larvae and enhanced biofilm formation independent of rrpB status. The oxidative and aerobic stress responses of rrpB- and rrpB+ strains suggest adaptation of C. jejuni within different hosts and niches that can be linked to specific MLST clonal complexes. PMID:28082970

  1. Hemodynamic significance of internal carotid artery disease

    DEFF Research Database (Denmark)

    Schroeder, T

    1988-01-01

    a significant improvement in baseline flow occur. Flow reserve determined by cerebral vasodilation, however, will improve in most patients with hemodynamic failure. In addition, some patients in the low-pressure group develop marked, but temporary, hyperperfusion after reconstruction of very high grade carotid...

  2. Central Hemodynamics for Management of Arteriosclerotic Diseases.

    Science.gov (United States)

    Hashimoto, Junichiro

    2017-08-01

    Arteriosclerosis, particularly aortosclerosis, is the most critical risk factor associated with cardiovascular, cerebrovascular, and renal diseases. The pulsatile hemodynamics in the central aorta consists of blood pressure, flow, and stiffness and substantially differs from the peripheral hemodynamics in muscular arteries. Arteriosclerotic changes with age appear earlier in the elastic aorta, and age-dependent increases in central pulse pressure are more marked than those apparent from brachial pressure measurement. Central pressure can be affected by lifestyle habits, metabolic disorders, and endocrine and inflammatory diseases in a manner different from brachial pressure. Central pulse pressure widening due to aortic stiffening increases left ventricular afterload in systole and reduces coronary artery flow in diastole, predisposing aortosclerotic patients to myocardial hypertrophy and ischemia. The widened pulse pressure is also transmitted deep into low-impedance organs such as the brain and kidney, causing microvascular damage responsible for lacunar stroke and albuminuria. In addition, aortic stiffening increases aortic blood flow reversal, which can lead to retrograde embolic stroke and renal function deterioration. Central pressure has been shown to predict cardiovascular events in most previous studies and potentially serves as a surrogate marker for intervention. Quantitative and comprehensive evaluation of central hemodynamics is now available through various noninvasive pressure/flow measurement modalities. This review will focus on the clinical usefulness and mechanistic rationale of central hemodynamic measurements for cardiovascular risk management.

  3. Frost stress evolution and winter pea ideotype in the context of climate warming at a regional scale

    Directory of Open Access Journals (Sweden)

    Castel Thierry

    2017-01-01

    Full Text Available Pea (Pisum sativum L. is an important crop in temperate regions for its high seed protein concentration that is particularly sensitive to abiotic stresses. The abrupt temperature increase known as the “1987/1988 temperature regime shift” that occurs over Europe is questioning how winter pea will perform in the changing climate. This study assessed the winter frost damage evolution along from 1961 to 2015 in Burgundy-Franche-Comté by using: (1 daily observed and gridded regional temperature data and (2 a validated crop winter frost stress model calibrated for pea. This study shows a global decrease of the frost stress nevertheless resulting from a subtle balance between the decrease in its intensity and the increase of the number of events. The frost stress evolution patterns with warming depend on both plant frost resistance level and acclimation rate and are still sensitive to winter climate fluctuations. This study provides relevant information for breeding performant winter crop ideotypes able to moderate detrimental effects of climate change and offering new cropping opportunities in temperate regions.

  4. Effect of stress states on the deformation behavior of Cu-based bulk metallic glass in the supercooled liquid region

    Energy Technology Data Exchange (ETDEWEB)

    Park, E.S., E-mail: espark@ameslab.gov [Division of Materials Science and Engineering, Ames Laboratory, U.S. DOE, Ames, IA 50011 (United States); Kim, H.J.; Bae, J.C. [Liquid Processing and Casting Technology R and D Department, Korea Institute of Industrial Technology, Inchon 406-130 (Korea, Republic of); Huh, M.Y. [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2014-02-15

    Highlights: • The effect of stress states on the deformation behavior in the SLR was studied in the Cu{sub 54}Ni{sub 6}Zr{sub 22}Ti{sub 18} BMG alloy. • The present BMG alloy displayed different plastic stress–strain curves under tensile and compressive plastic strain states. • The calculation of the diffusivity of Cu atoms indicated that the diffusion of Cu atoms is retarded by compressive stress and accelerated by tensile stress. • The fast diffusion of Cu atoms under tensile stress caused faster crystallization leading to a fast strain-hardening during the tensile plastic deformation. -- Abstract: The effect of stress states on the deformation behavior of the Cu{sub 54}Zr{sub 22}Ti{sub 18}Ni{sub 6} bulk metallic glass (BMG) alloy was studied in the supercooled liquid region. At 723 K, Newtonian plastic flow governed the deformation during the compression test, whereas strain-hardening occurred during the tensile test. At 733 K, a fast failure was observed during tensile test. The diffusion rate of Cu atoms in the BMG alloy plays an important role in the deformation behavior. The fast diffusion of Cu atoms under the tensile stress state caused faster crystallization leading to a fast strain-hardening during the tensile plastic deformation.

  5. Discussion: "Comparison of Statistical Methods for Assessing Spatial Correlations Between Maps of Different Arterial Properties" (Rowland, E. M., Mohamied, Y., Chooi, K. Y., Bailey, E. L., and Weinberg, P. D., 2015, ASME J. Biomech. Eng., 137(10), p. 101003): An Alternative Approach Using Segmentation Based on Local Hemodynamics.

    Science.gov (United States)

    Himburg, Heather A; Grzybowski, Deborah M; Hazel, Andrew L; LaMack, Jeffrey A; Friedman, Morton H

    2016-09-01

    The biological response of living arteries to mechanical forces is an important component of the atherosclerotic process and is responsible, at least in part, for the well-recognized spatial variation in atherosusceptibility in man. Experiments to elucidate this response often generate maps of force and response variables over the arterial surface, from which the force-response relationship is sought. Rowland et al. discussed several statistical approaches to the spatial autocorrelation that confounds the analysis of such maps and applied them to maps of hemodynamic stress and vascular response obtained by averaging these variables in multiple animals. Here, we point out an alternative approach, in which discrete surface regions are defined by the hemodynamic stress levels they experience, and the stress and response in each animal are treated separately. This approach, applied properly, is insensitive to autocorrelation and less sensitive to the effect of confounding hemodynamic variables. The analysis suggests an inverse relation between permeability and shear that differs from that in Rowland et al. Possible sources of this difference are suggested.

  6. The extent and causes of stress in teachers in the George region

    African Journals Online (AJOL)

    Erna Kinsey

    A questionnaire, of which one section was the "Fimian Teacher Stress Inventory", was administered to 132 secondary teachers. The data ..... Table 4. ANOVA results depicting the relationship between factors that cause stress in the teaching environment and certain biographical variables ..... and parents to handle incidents.

  7. Concurrent OCT imaging of stimulus evoked retinal neural activation and hemodynamic responses

    Science.gov (United States)

    Son, Taeyoon; Wang, Benquan; Lu, Yiming; Chen, Yanjun; Cao, Dingcai; Yao, Xincheng

    2017-02-01

    It is well established that major retinal diseases involve distortions of the retinal neural physiology and blood vascular structures. However, the details of distortions in retinal neurovascular coupling associated with major eye diseases are not well understood. In this study, a multi-modal optical coherence tomography (OCT) imaging system was developed to enable concurrent imaging of retinal neural activity and vascular hemodynamics. Flicker light stimulation was applied to mouse retinas to evoke retinal neural responses and hemodynamic changes. The OCT images were acquired continuously during the pre-stimulation, light-stimulation, and post-stimulation phases. Stimulus-evoked intrinsic optical signals (IOSs) and hemodynamic changes were observed over time in blood-free and blood regions, respectively. Rapid IOSs change occurred almost immediately after stimulation. Both positive and negative signals were observed in adjacent retinal areas. The hemodynamic changes showed time delays after stimulation. The signal magnitudes induced by light stimulation were observed in blood regions and did not show significant changes in blood-free regions. These differences may arise from different mechanisms in blood vessels and neural tissues in response to light stimulation. These characteristics agreed well with our previous observations in mouse retinas. Further development of the multimodal OCT may provide a new imaging method for studying how retinal structures and metabolic and neural functions are affected by age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), and other diseases, which promises novel noninvasive biomarkers for early disease detection and reliable treatment evaluations of eye diseases.

  8. Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants.

    Directory of Open Access Journals (Sweden)

    Caroline C O'Brien

    Full Text Available Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design.Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D 'clouds' of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively to individual strut-wall configurations (average displacement error ~15 μm. This framework facilitated hemodynamic simulation (n = 1 vessel, showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors.Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments.

  9. Hemodynamic signals of mixed messages during a social exchange.

    Science.gov (United States)

    Zucker, Nancy L; Green, Steven; Morris, James P; Kragel, Philip; Pelphrey, Kevin A; Bulik, Cynthia M; LaBar, Kevin S

    2011-06-22

    This study used functional magnetic resonance imaging to characterize hemodynamic activation patterns recruited when the participants viewed mixed social communicative messages during a common interpersonal exchange. Mixed messages were defined as conflicting sequences of biological motion and facial affect signals that are unexpected within a particular social context (e.g. observing the reception of a gift). Across four social vignettes, valenced facial expressions were crossed with rejecting and accepting gestures in a virtual avatar responding to presentation of a gift from the participant. The results indicate that conflicting facial affect and gesture activated superior temporal sulcus, a region implicated in expectancy violations, as well as inferior frontal gyrus and putamen. Scenarios conveying rejection differentially activated the insula and putamen, regions implicated in embodied cognition, and motivated learning, as well as frontoparietal cortex. Characterizing how meaning is inferred from integration of conflicting nonverbal communicative cues is essential to understand nuances and complexities of human exchange.

  10. Ocular hemodynamics in patients with rhegmatogenous retinal detachment

    Directory of Open Access Journals (Sweden)

    N. H. Zavgorodnya

    2014-10-01

    Full Text Available Aim. In case of retinal detachment atrophic processes lead to irreversible loss of functions within 4–6 days, it happens on underlying low ocular blood flow. In order to evaluate the degree of violation of regional hemodynamics in patients with retinal detachment two groups of patients were examined: the main group (52 patients with rhegmatogenous retinal detachment and the control group (24 myopic patients with lattice form of peripheral chorioretinal dystrophy. Methods and results. Doppler and reography results had been compared, significant decrease of blood flow in patients with retinal detachment was found. No differences between affected and fellow eye in these patients, close negative correlation between the level of ocular blood flow and the degree of myopia in the control group. Conclusion. This demonstrates the feasibility of actions to improve regional blood flow in patients operated on for retinal detachment.

  11. Numerical Assessment of Novel Helical/Spiral Grafts with Improved Hemodynamics for Distal Graft Anastomoses.

    Directory of Open Access Journals (Sweden)

    Foad Kabinejadian

    Full Text Available In the present work, numerical simulations were conducted for a typical end-to-side distal graft anastomosis to assess the effects of inducing secondary flow, which is believed to remove unfavourable flow environment. Simulations were carried out for four models, generated based on two main features of 'out-of-plane helicity' and 'spiral ridge' in the grafts as well as their combination. Following a qualitative comparison against in vitro data, various mean flow and hemodynamic parameters were compared and the results showed that helicity is significantly more effective in inducing swirling flow in comparison to a spiral ridge, while their combination could be even more effective. In addition, the induced swirling flow was generally found to be increasing the wall shear stress and reducing the flow stagnation and particle residence time within the anastomotic region and the host artery, which may be beneficial to the graft longevity and patency rates. Finally, a parametric study on the spiral ridge geometrical features was conducted, which showed that the ridge height and the number of spiral ridges have significant effects on inducing swirling flow, and revealed the potential of improving the efficiency of such designs.

  12. Hemodynamic analysis of intracranial aneurysms using phase-contrast magnetic resonance imaging and computational fluid dynamics

    Science.gov (United States)

    Zhao, Xuemei; Li, Rui; Chen, Yu; Sia, Sheau Fung; Li, Donghai; Zhang, Yu; Liu, Aihua

    2017-04-01

    Additional hemodynamic parameters are highly desirable in the clinical management of intracranial aneurysm rupture as static medical images cannot demonstrate the blood flow within aneurysms. There are two ways of obtaining the hemodynamic information—by phase-contrast magnetic resonance imaging (PCMRI) and computational fluid dynamics (CFD). In this paper, we compared PCMRI and CFD in the analysis of a stable patient's specific aneurysm. The results showed that PCMRI and CFD are in good agreement with each other. An additional CFD study of two stable and two ruptured aneurysms revealed that ruptured aneurysms have a higher statistical average blood velocity, wall shear stress, and oscillatory shear index (OSI) within the aneurysm sac compared to those of stable aneurysms. Furthermore, for ruptured aneurysms, the OSI divides the positive and negative wall shear stress divergence at the aneurysm sac.

  13. Sex Differences in the Effects of Acute and Chronic Stress and Recovery after Long-Term Stress on Stress-Related Brain Regions of Rats

    NARCIS (Netherlands)

    Lin, Yanhua; Ter Horst, Gert J.; Wichmann, Romy; Bakker, Petra; Liu, Aihua; Li, Xuejun; Westenbroek, Christel

    Studies show that sex plays a role in stress-related depression, with women experiencing a higher vulnerability to its effect. Two major targets of antidepressants are brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate response element-binding protein (CREB). The aim of this

  14. Local versus regional active stress field in 5900m San Gregorio Magno 1 well (southern Apennines, Italy).

    Science.gov (United States)

    Pierdominici, S.; Montone, P.; Mariucci, M. T.

    2009-04-01

    The aim of this work is to characterize the local stress field in a peculiar sector of the southern Apennines by analyzing borehole breakouts, fractures and logging data along the San Gregorio Magno 1 deep well, and to compare the achieved stress field with the regional one. The study area is characterized by diffuse low-Magnitude seismicity, although in historical times it has been repeatedly struck by moderate to large earthquakes. We have analyzed in detail the 5900m San Gregorio Magno 1 well drilled in 1996-97 by ENI S.p.A. and located very close (1.3 km away) to the Irpinia Fault. This fault was responsible of the strongest earthquake happened in this area, the 23rd November 1980 M6.9 earthquake that produced the first unequivocal historical surface faulting ever documented in Italy. The mainshock enucleated on a fault 38 km-long with a strike of 308° and 60-70° northeast-dipping, consistent with a NE-SW T-axis and a normal faulting tectonic regime. Borehole breakouts, active faults and focal mechanism solutions have allowed to define the present-day stress along and around the San Gregorio Magno 1 well and other analysis (logging data) to discriminate the presence of fracture zones and/or faults at depth. We have considered data from 1200m to the bottom of San Gregorio Magno 1 well. Our analysis of stress-induced wellbore breakouts shows an inhomogeneous direction of minimum horizontal stress (N359+-31°) orientation along the well. This direction is moderately consistent with the Shmin-trend determined from breakouts in other wells in this region and also with the regional active stress field inferred from active faults and earthquake focal plane solutions (N44 Shmin oriented). For this reason we have computed for each breakout zone the difference between the local trend and the regional one; comparing these breakout rotations with the spikes or changing trend of logs we have identified possible fractures or faults at different depths. We have correlated

  15. Future Projections from the Effects of Heat Stress on Livestock: for the US and New England Region

    Science.gov (United States)

    McCabe, E.; Buzan, J. R.; Huber, M.; Krishnan, S.

    2015-12-01

    Future climate change will result in variations in heat stress experienced by livestock, which will consequently impact health, well-being, and yield. In this study, we estimate future yield changes for livestock due to heat stress in New England. We use the Community Land Model version 4.5 (CLM4.5), a component of the Community Earth System Model (CESM) that is developed by the National Center for Atmospheric Research (NCAR). The simulation uses RCP8.5 boundary conditions, and is driven by CCSM4 atmospheric forcing from the CMIP5 archive, that conducts simulations of the past and next century. Heat stress metrics are calculated using the HumanIndexMod in CLM4.5 for the early and late 21st century. For example, the humidity index for comfort and physiology, wet bulb temperature and swamp cooler efficiency. Results indicate that in the New England Region, temperatures will increase by 4 °C and in New Hampshire specifically by 3 °C. Temperature humidity index for comfort and physiology, swamp cooler efficiency and wet bulb are all projected to rise by the end of the century. While it is obvious that these elevations in temperature will have a negative effect on animals inhibiting their performance and output, our analysis also emphasizes the role of changes in humidity in heat stress. We show that heat stress caused by temperature and humidity increases, will decrease overall production yield for dairy and beef cattle, sows, finishing hogs and poultry, as a result of heat stress and other major climatic factors. We estimate and discuss resulting economic losses for the livestock industries and the impact in the United States and New England Region.

  16. Regional differences in systolic active stress profiles in the normal beating heart. Assessment using an ultrasound based mathematical model.

    Science.gov (United States)

    McLaughlin, M; Langeland, S; Streb, W; Marciniak, M; D'Hooge, J; Bijnens, B; Claus, P

    2004-01-01

    Active stress (sigmaA) developed by cardiac muscle has been measured in isolated muscle preparations, under physiological loading conditions, by subtracting the passive stress (sigmaP) from the total stress (sigmaT). We previously developed a mechanical model based on M-mode ultrasound imaging to calculate these stresses in beating hearts. However, this model was based on one-dimensional imaging information and could not estimate regional differences in sigmaA. In the current study this model was improved by including two-dimensional B-mode echocardiographic data. In a porcine model a micro-manometer tipped catheter was used to measure left-ventricular pressure (LVP) and B-mode ultrasound images were recorded in a short-axis view. On the ultrasound image points in the mid-wall were selected and tracked to completely define the deformation of the myocardium. A kinematic model of the LV was then constructed from the displacement vectors of these points. sigmaT was calculated from the LVP. The material parameters for an exponential stress/strain relation were estimated during the diastolic E-wave when it was assumed that sigmaA = 0. These parameters were used to calculate sigmaP during systole and by subtracting this from sigmaT, sigmaA was calculated. The timing and shape of sigmaA profiles match those obtained from isolated muscle experiments. SigmaA was higher and peaked sooner in the posterior wall than in the anterior wall. Regional active stress estimation is possible in normal beating hearts.

  17. Effects of diagnostic guidewire catheter presence on translesional hemodynamic measurements across significant coronary artery stenoses.

    Science.gov (United States)

    Banerjee, Rupak K; Back, Lloyd H; Back, Martin R

    2003-01-01

    This study gains insight on the nature of flow blockage effects of small guidewire catheter sensors in measuring mean trans-stenotic pressure gradients Deltap across significant coronary artery stenoses. Detailed pulsatile hemodynamic computations were made in conjunction with previously reported clinical data in a group of patients with clinically significant coronary lesions before angioplasty. Results of this study ascertain changes in hemodynamic conditions due to the insertion of a guidewire catheter (di=0.46 mm) across the lesions used to directly determine the mean pressure gradient (Deltap) and fall in distal mean coronary pressure (pr). For the 32 patient group of Wilson et al. [1988] (minimal lesion diameter dm=0.95 mm; 90% mean area stenosis; proximal measured coronary flow reserve (CFR) of 2.3 in the abnormal range) the diameter ratio of guidewire catheter to minimal lesion was 0.48, causing a tighter "artifactual" mean area stenosis of 92.1%. The results of the computations indicated a significant shift in the Deltap-Q relation due to guidewire induced increases in flow resistances (R=Deltap/Q) of 110% for hyperemic flow, a 35% blockage in hyperemic flow (Qh) and a phase shift of the coronary flow waveform to systolic predominance. These alterations in flow resulted in a fall in distal mean coronary pressure (at lower mean flow rates) below the patho-physiological range of prh approximately 55 mmHg, which is known to cause ischemia in the subendocardium (Brown et al. [1984]) and coincides with symptomatic angina. Transient wall shear stress levels in the narrow throat region (with flow blockage) were of the order of levels during hyperemic conditions for patho-physiological flow. In the separated flow region along the distal vessel wall, vortical flow cells formed periodically during the systolic phase when instantaneous Reynolds numbers Ree(t) exceeded about 110. For patho-physiological flow without the presence of the guidewire these vortical flow

  18. Hemodynamic regulation of MMP-2 and MMP-9: roles in angiogenesis and migration

    OpenAIRE

    Von Offenberg Sweeney, Nicholas

    2004-01-01

    Hemodynamic forces generated by the flow of blood are crucial in maintaining homeostasis within the blood vessel wall. These forces, namely cyclic strain and shear stress are intricately involved in vascular remodeling, a process which underlies the pathogenesis of cardiovascular diseases such as atherosclerosis and restenosis. Since degradation of the extracellular matrix scaffold enables reshaping of tissue, the role matrix metalloproteinases (MMPs) has become the object of intense recen...

  19. Regional bone geometry of the tibia in triathletes and stress reactions--an observational study.

    Science.gov (United States)

    Newsham-West, Richard J; Lyons, Brett; Milburn, Peter D

    2014-03-01

    The association between tibial morphology and tibial stress fractures or tibial stress syndrome was examined in triathletes with an unusually high incidence of these injuries. A cross-sectional study design examined associations between tibial geometry from MRI images and training and injury data between male and female triathletes and between stress fracture (SF) and non-stress fracture (NSF) groups. Fifteen athletes (7 females, 8 males) aged 17-23 years who were currently able to train and race were recruited from the New Zealand Triathlete Elite Development Squad. Geometric measurements were taken at 5 zones along the tibia using MRI and compared between symptomatic and asymptomatic tibiae subjects. SF tibiae displayed either oedema within the cancellous bone and/or stress fracture on MRI. When collapsed across levels, symptomatic tibiae had thicker medial cortices (F1,140=9.285, p=0.003), thicker lateral cortices (F1,140=10.129, p=0.002) and thinner anterior cortices (F1,140=14.517, p=0.000) than NSF tibiae. Only medial cortex thickness in SF tibia was significantly different (F4,140=3.358, p=0.012) at different levels. Follow-up analysis showed that athletes showing oedema within the cancellous bone and/or stress fracture on MRI had, within 2 years of analysis, subsequently taken time off training and racing due a tibial stress fracture. The thinner anterior cortex in SF tibiae is associated with a stress reaction in these triathletes. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  20. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  1. Stress correlations in the transition region of discontinuously thickening suspension flows

    Science.gov (United States)

    Morris, Jeffrey

    In concentrated suspensions of particles in liquids, the apparent viscosity and the normal stresses are often found to undergo an abrupt transition from a low-viscosity to a high-viscosity state. This behavior happens in a range of materials, for example dispersions of sub-micron spheres in organic liquids to 20-micron diameter corn starch particles in water. While the mechanism may differ for different materials, one scenario which is able to explain this type of behavior is that as the shear stress increases, a stabilizing force which maintains liquid-filled gaps between the particles transitions to one in which contact occurs and frictional interactions between the particles plays a role. This lubricated-frictional transition is explored using an established simulation approach for spherical particles in viscous liquid. The behavior will first be shown to exhibit a shear rate- or stress-induced transition which has features of a classical phase transition. The point equivalent to a critical point is thus the point at which the variation of the shear stress (and typically also the mean particle normal stress) with respect to the shear rate becomes infinite. This point is associated with a pairing of solid fraction and friction coefficient , ϕ and μ respectively. The temporal fluctuations and spatial correlations of the mixture stress are examined and shown to exhibit a striking change as this transition is crossed. NSF 1605283.

  2. Effect of aneurysm and ICA morphology on hemodynamics before and after flow diverter treatment.

    Science.gov (United States)

    Larrabide, Ignacio; Geers, Arjan J; Morales, Hernán G; Aguilar, Martha L; Rüfenacht, Daniel A

    2015-04-01

    Flow diverter (FD) treatment aims to slow down blood flow inside the aneurysm and increase the average time that blood resides in the aneurysm. To investigate the relationship between vessel and aneurysm morphology and their influence on the way in which braided FDs change intra-aneurysmal hemodynamics. Twenty-three patient-specific intracranial aneurysm models at the supraclinoid segment of the internal carotid artery were studied. Vessel and aneurysm morphology was quantified and blood flow was modeled with computational fluid dynamics simulations. The relation between morphologic variables and the hemodynamic variables, WSS (wall shear stress) and totime (ratio between the aneurysm volume and inflow at the aneurysm neck), was assessed statistically. Intra-aneurysmal flow was less dependent on the vessel than on aneurysm morphology. In summary, after treatment with a FD, a greater aneurysm flow reduction and redirection to the vessel main stream should be expected for (a) aneurysms located further away from the curvature peak, (b) aneurysms on the inner side of the bend, (c) aneurysms with no proximal stenosis, and (d) larger aneurysms. Although the change in intra-aneurysmal hemodynamics after FD treatment strongly depends on the morphology of the aneurysm, the hemodynamic effect of a FD is also linked to the parent vessel morphology and the position and orientation of the aneurysm with respect to it. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  3. Physiology of school burnout in medical students: Hemodynamic and autonomic functioning

    Directory of Open Access Journals (Sweden)

    Ross W. May

    2016-09-01

    Full Text Available This study investigated the relationship between burnout and hemodynamic and autonomic functioning in both medical students (N = 55 and premedical undergraduate students (N = 77. Questionnaires screened for health related issues and assessed school burnout and negative affect symptomatology (anxiety and depression. Continuous beat-to-beat blood pressure (BP through finger plethysmography and electrocardiogram (ECG monitoring was conducted during conditions of baseline and cardiac stress induced via the cold pressor task to produce hemodynamic, heart rate variability, and blood pressure variability indices. Independent sample t-tests demonstrated that medical students had significantly higher school burnout scores compared to their undergraduate counterparts. Controlling for age, BMI, anxiety and depressive symptoms, multiple regression analyses indicated that school burnout was a stronger predictor of elevated hemodynamics (blood pressure, decreased heart rate variability, decreased markers of vagal activity and increased markers of sympathetic tone at baseline for medical students than for undergraduates. Analyses of physiological values collected during the cold pressor task indicated greater cardiac hyperactivity for medical students than for undergraduates. The present study supports previous research linking medical school burnout to hemodynamic and autonomic functioning, suggests biomarkers for medical school burnout, and provides evidence that burnout may be implicated as a physiological risk factor in medical students. Study limitations and potential intervention avenues are discussed.

  4. Emergency management of hemodynamically unstable pelvic fractures

    Directory of Open Access Journals (Sweden)

    ZHAO Xiao-gang

    2012-02-01

    Full Text Available 【Abstract】Pelvic fractures are serious injuries. Death within 24 hours is most often a result of acute blood loss. The emergency management of these patients is challenging and controversial. The key issues in its management are identifying the site(s of hemorrhage and then controlling the bleeding. Management of hemodynamically unstable patients with pelvic fracture requires a multidisci- plinary team. The issues addressed in this management algorithm are diagnostic evaluation, damage control resuscitation, indications for noninvasive pelvic stabilization, preperitoneal pelvic packing and the critical decisions concerning surgical options and angiography. This review article focuses on the recent body of know- ledge on those determinations. Key words: Pelvis; Hemodynamic; Emergencies; Practice management

  5. Self-reported social functioning and prefrontal hemodynamic responses during a cognitive task in schizophrenia.

    Science.gov (United States)

    Pu, Shenghong; Nakagome, Kazuyuki; Itakura, Masashi; Yamanashi, Takehiko; Sugie, Takuya; Miura, Akehiko; Satake, Takahiro; Iwata, Masaaki; Nagata, Izumi; Kaneko, Koichi

    2015-10-30

    Impaired social functioning is a characteristic of schizophrenia that affects patients' quality of life. The aim of the study was to assess prefrontal hemodynamic responses during a cognitive task and establish its influence on psychiatric symptoms, cognitive function, global functioning, and self-reported social functioning in patients with schizophrenia. Thirty-three patients with schizophrenia and 30 age-and sex-matched healthy controls participated in the study. We measured hemodynamic responses in the prefrontal and superior temporal cortical surface areas with 52-channel near-infrared spectroscopy (NIRS) during a verbal fluency task (VFT). Self-reported social functioning was assessed using the Social Functioning Scale (SFS). Regional hemodynamic responses were significantly smaller in the prefrontal and temporal regions in subjects with schizophrenia than in the controls, and prefrontal hemodynamic responses during the VFT showed a strong correlation with SFS total scores. These results suggest an association between self-reported social functioning and prefrontal activation in subjects with schizophrenia. The present study provides evidence that NIRS imaging could be helpful in understanding the neural basis of social functioning. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. The relationship between the prefrontal activation during a verbal fluency task and stress-coping style in major depressive disorder: a near-infrared spectroscopy study.

    Science.gov (United States)

    Pu, Shenghong; Nakagome, Kazuyuki; Yamada, Takeshi; Yokoyama, Katsutoshi; Matsumura, Hiroshi; Mitani, Hideaki; Adachi, Akiko; Nagata, Izumi; Kaneko, Koichi

    2012-11-01

    This study aimed to identify coping styles used by patients with major depressive disorder (MDD) in comparison with those used by healthy controls, and to explore their association with prefrontal hemodynamic response related to a cognitive task. Regional hemodynamic changes were monitored during a verbal fluency task (VFT) using a 52-channel near-infrared spectroscopy (NIRS) apparatus in 26 MDD patients in depressive state and 30 matched healthy controls, and their correlation with coping styles assessed by Coping Inventory for Stressful Situations (CISS) were examined. We found the Emotion-oriented coping style was significantly higher, whereas the Task-oriented coping and Avoidance-oriented coping style were lower in the MDD group compared with controls. Emotion-oriented coping style positively correlated with subjective assessment of depression severity. Regional hemodynamic changes were significantly smaller in the MDD group than in the control group in prefrontal and temporal regions, and positively correlated with Task-oriented coping (adaptive coping) in the bilateral ventrolateral and dorsolateral prefrontal cortex, and the midline fronto-polar and bilateral orbitofrontal cortex regions. These findings suggest coping styles may be considered an important source of knowledge for patients who struggle with the illness and for mental health professionals who work with MDD patients, and that hemodynamic response in the ventrolateral and dorsolateral prefrontal cortex, midline fronto-polar, and orbitofrontal cortex regions during a VFT may reflect the adaptive coping (Task-oriented coping) style in MDD patients in depressive state. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Immunologic, hemodynamic, and adrenal incompetence in cirrhosis

    DEFF Research Database (Denmark)

    Risør, Louise Madeleine; Bendtsen, Flemming; Møller, Søren

    2015-01-01

    Acute kidney injury (AKI) is one of the most severe complications of cirrhosis and is associated with significant morbidity and mortality. Liver fibrosis and liver insufficiency, portal hypertension, systemic vasodilation, and a subsequent hyperdynamic circulation undermine the renal and cardiac...... function, making cirrhotic patients more susceptible to hemodynamic incidents. In addition, the immune system is impaired in cirrhosis, leading to an exaggerated production of vasoactive mediators, and the adrenal cortisol response is insufficient, which causes further impairment of the vascular tonus...

  8. HEMODYNAMIC EFFECTS OF XENON ANESTHESIA IN CHILDREN

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    M. V. Bykov

    2014-01-01

    Full Text Available The study was aimed at hemodynamic effects of xenon on operative interventions in children. Patients and methods: the study involved 30 5-17-year-old children – 10 (33.3% girls and 20 (66.7% boys with ASA score 1-3 admitted for surgical treatment. The children underwent endotracheal anesthesia with xenon-oxygen mixture (Xe:O2 = 60-65:30% and fentanyl (2.5‑3.5  mcg/kg per hour for the following operations: appendectomy – 10 (33.3% patients, herniotomy – 8 (26.7% patients, Ivanissevich procedure – 6 (20.0% patients, plastic surgery of posttraumatic defects of skin and soft tissues – 4 (13.3% patients, abdominal adhesiotomy – 2 (6.7% patients. Central hemodynamics was studied echocardiographically (Philips HD 11, the Netherlands using the Teichholz technique along the cephalocaudal axis (parasternal access. Results: the anesthesia was notable for hemodynamic stability during the operation: as a result, a statistically significant (p < 0.05 increase in systolic, diastolic and mean arterial pressure by 10, 18 and 17%, respectively, was observed. Conclusion: the analysis demonstrated that xenon anesthesia improves lusitropic myocardial function statistically significantly increasing cardiac output by 12% by way of increasing stroke volume by 30%. 

  9. Conservative hemodynamic surgery for varicose veins.

    Science.gov (United States)

    Criado, Enrique; Luján, Salvador; Izquierdo, Luis; Puras, Enrique; Gutierrez, Miguel; Fontcuberta, Juan

    2002-03-01

    Conservative hemodynamic surgery for varicose veins is a minimally invasive, nonablative technique that preserves the saphenous vein and helps avoid excision of varicosities. It represents a physiologic approach to the surgical treatment of varicose veins based on knowledge of the underlying venous pathophysiology gained through detailed duplex scanning. A change in venous hemodynamics is attained through fragmentation of the blood column by interruption of the refluxing saphenous trunks, closure of the origin of the refluxing varicose branches, and preservation of the communicating veins that drain the incompetent varicose veins into the deep venous system. After surgery, varicose veins regress through a reduction in hydrostatic pressure and efficient emptying of the superficial system by the musculo-venous pump. Obvious advantages of this technique are that it is done in an ambulatory setting, minimizes the risk of surgical complications, and permits a rapid return to full activity. The long-term hemodynamic improvement and recurrence rate of this technique remain to be established. Copyright 2002 by W.B. Saunders Company

  10. Evaluation of aneurysm-associated wall shear stress related to morphological variations of circle of Willis using a microfluidic device.

    Science.gov (United States)

    Nam, Seong-Won; Choi, Samjin; Cheong, Youjin; Kim, Yeon-Hee; Park, Hun-Kuk

    2015-01-21

    Although microfluidic systems have been important tools in analytical chemistry, life sciences, and medical research, their application was rather limited for drug-screening and biosensors. Here, we described a microfluidic device consisting of a multilayer micro-channel system that represented the hemodynamic cerebral vascular system. We analyzed wall shear stresses related to aneurysm formation in the circle of Willis (CoW) and their morphological variations using this system. This device was controlled by pneumatic valves, which occluded various major arteries by closing the associated channels. The hemodynamic analysis indicated that higher degrees of shear stress occurred in an anterior communicating artery (ACoA), particularly in the hypoplastic region of the posterior communicating artery (PCoA) and the P1 segment. Furthermore, occlusion of a common carotid artery (CCA) or a middle cerebral artery (MCA) increased the shear stress, whereas occlusion of a vertebral artery (VA) decreased the shear stress. These results indicate that the morphological variation of the CoW may affect aneurysm formation resulting from increased wall shear stress. Therefore, the technique described in this paper provides a novel method to investigate the hemodynamics of complex cerebral vascular systems not accessible from previous clinical studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Stress

    OpenAIRE

    Jensen, Line Skov; Lova, Lotte; Hansen, Zandra Kulikovsky; Schønemann, Emilie; Larsen, Line Lyngby; Colberg Olsen, Maria Sophia; Juhl, Nadja; Magnussen, Bogi Roin

    2012-01-01

    Stress er en tilstand som er meget omdiskuteret i samfundet, og dette besværliggør i en vis grad konkretiseringen af mulige løsningsforslag i bestræbelsen på at forebygge den såkaldte folkesygdom. Hovedkonklusionen er, at selv om der bliver gjort meget for at forebygge, er der ikke meget der aktivt kan sættes i værk for at reducere antallet af stressramte, før en fælles forståelse af stressårsager og effektiv stresshåndtering er fremlagt. Problemformuleringen er besvaret gennem en undersø...

  12. Workplace bullying and post-traumatic stress symptoms among family physicians in Lithuania: An occupation and region specific approach

    Directory of Open Access Journals (Sweden)

    Vilija Malinauskiene

    2014-12-01

    Full Text Available Objectives: The study investigated associations between workplace bullying and post-traumatic stress symptoms as compared to and controlled for associations between the latter and other psychosocial stress factors at work and in everyday life. The study employed a representative sample of Lithuanian family physicians, hence investigated a particularly resourceful occupational group in a geographical region earlier found to have a high risk context for exposure to bullying at work. Material and Methods: With a response rate of 89.2%, a total of 323 family physicians filled in an anonymous questionnaire on workplace bullying, post-traumatic symptomatology (IES-R, other psychosocial stressors at work and in everyday life, personal health resources (sense of coherence, behavioral characteristics and demographic variables. The statistical software SPSS 14.0, Windows was used in the analysis. Associations were tested using a multivariate logistic regression analysis. Results: A high prevalence of bullying was found among family physicians in Lithuania, with 13% of them experiencing severe workplace bullying and 17.3% experiencing more occasional incidents of bullying. The prevalence of post-traumatic stress symptoms was also high with 15.8% scoring above the standardized cut-off thresholds for post-traumatic stress disorder. The odds ratio (OR of severe bullying for post-traumatic stress after adjustment for age and gender was 8.05 (95% confidence intervals (CI: 3.80–17.04. In the fully adjusted model it increased to 13.88 (95% CI: 4.68–41.13 indicating cumulative effects of all the investigated stressors. Conclusions: Workplace bullying is particularly prevalent among Lithuanian family physicians, as are the symptoms of post-traumatic distress. Strong associations between post-traumatic stress and exposure to severe bullying indicate that bullying is a significant source of mental health.

  13. Workplace bullying and post-traumatic stress symptoms among family physicians in Lithuania: an occupation and region specific approach.

    Science.gov (United States)

    Malinauskiene, Vilija; Einarsen, Staale

    2014-12-01

    The study investigated associations between workplace bullying and post-traumatic stress symptoms as compared to and controlled for associations between the latter and other psychosocial stress factors at work and in everyday life. The study employed a representative sample of Lithuanian family physicians, hence investigated a particularly resourceful occupational group in a geographical region earlier found to have a high risk context for exposure to bullying at work. With a response rate of 89.2%, a total of 323 family physicians filled in an anonymous questionnaire on workplace bullying, post-traumatic symptomatology (IES-R), other psychosocial stressors at work and in everyday life, personal health resources (sense of coherence), behavioral characteristics and demographic variables. The statistical software SPSS 14.0, Windows was used in the analysis. Associations were tested using a multivariate logistic regression analysis. A high prevalence of bullying was found among family physicians in Lithuania, with 13% of them experiencing severe workplace bullying and 17.3% experiencing more occasional incidents of bullying. The prevalence of post-traumatic stress symptoms was also high with 15.8% scoring above the standardized cut-off thresholds for post-traumatic stress disorder. The odds ratio (OR) of severe bullying for post-traumatic stress after adjustment for age and gender was 8.05 (95% confidence intervals (CI): 3.80-17.04). In the fully adjusted model it increased to 13.88 (95% CI: 4.68-41.13) indicating cumulative effects of all the investigated stressors. Workplace bullying is particularly prevalent among Lithuanian family physicians, as are the symptoms of post-traumatic distress. Strong associations between post-traumatic stress and exposure to severe bullying indicate that bullying is a significant source of mental health.

  14. Pacing stress echocardiography

    Directory of Open Access Journals (Sweden)

    Agrusta Marco

    2005-12-01

    Full Text Available Abstract Background High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility. Methods The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon. To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer/end-systolic volume index (biplane Simpson rule. The heart rate is determined from ECG. Conclusion Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker. The force-frequency can be defined as up- sloping (normal when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress

  15. Pacing stress echocardiography

    Science.gov (United States)

    Gligorova, Suzana; Agrusta, Marco

    2005-01-01

    Background High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility. Methods The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG. Conclusion Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker. The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an

  16. Changes in Regional Stress Associated with the 1999 Chi-Chi, Taiwan, Earthquake Based on Focal Mechanisms

    Science.gov (United States)

    Jiang, J.; Huang, B.; Tsai, Y.; Shin, T.

    2004-12-01

    The 1999 Mw7.6 Chi-Chi earthquake was the most recent prominent earthquake in Taiwan. The mainshock was followed by substantial number of strong aftershocks. Pre- and post-mainshock focal mechanisms of the 1999 Chi-Chi earthquake are analyzed to characterize spatial and temporal variation around the Chelungpu fault, which ruptured during the mainshock. The Frohlich¡¦s triangle diagram used to define the classification of earthquake focal mechanisms. We categorized the types of earthquake focal mechanisms as either normal , strike-slip, or thrust according to the corresponding maximum plunges is the pressure axis (P), null axis(B), or tension axis (T). The strain and stress orientations was estimated based on moment tensor summation and focal mechanism stress inversion respectively. The stress is caused by tectonic sources, but the strain results from the application of stress to particular structure of the crust. We show the difference between stress and strain directions and on what we can learn from this observation about tectonic processes in the volume studied. A comparison of the directions of strain and stress tensors showed close agreement for subvolumes with predominantly thrust and strike-slip faulting. This article describe and characterize the spatial and temporal distribution of earthquake focal mechanisms in the region of the 1999 Chi-Chi earthquake before(107 event) and after(401 event) the mainshock within the period from 1 January 1991 to 31 December 2001. Whereas the earthquake focal mechanism data suggest some spatial and temporal complexity in Central Taiwan, the overall pattern can be characterized by cluster analysis of grouped earthquake according to the seismicity trend and type of focal mechanisms. The aftershock focal mechanisms are dominant by strike-slip type even though the mainshock is thrust fault type. In contrast, for temporal distribution of different kind of aftershock focal mechanisms, which occurrence sequence is strike

  17. COMPARISON BETWEEN THE ANALGESIC CHARACTERS AND HEMODYNAMIC CHANGES OF 2% LIGNOCAINE ALONE AND 2% LIGNOCAINE WITH CLONIDINE IN EPIDURAL BLOCKADE

    Directory of Open Access Journals (Sweden)

    Sony Sharma

    2015-01-01

    Full Text Available INTRODUCTION: Pain is as old as mankind and so is the quest for its control. It is defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage”. 1 Pain relief is a growing concern to anaesthesiologist, since no single analgesia is free from side effect, so it is a challenge to provide pain relief without much side effect like sedation, respiratory depression or problem like nausea & vomiting. Regional anaesthesia techniques generously offer adequate pain control for early mobilization and compliance with physiotherapy, they also provide additional benefits of decreased surgical stress response 2 improved myocardial stability, 3,4 rapid recovery of bowel function 5,6 and reduced risk of thromboembolic events like deep vein thrombosis and pulmonary embolism. 7 As a result it is also associated with reduction in postoperative morbidity and mortality. 8 Epidural anaesthesia has become increasingly popular in recent years for surgeries of lower abdomen, pelvis and lower limbs as it offer excellent operating conditions and is relatively safe for patients. It offers benefits in the form of greater hemodynamic stability and provision of postoperative analgesia via an epidural catheter. Clonidine is a partial α - 2 adrenergic agonist which, when administered by epidural route, has analgesic properties and potentiates the effect of local anesthetics . 9 Clonidine has analgesic effect at spinal level mediated by alpha - 2 adrenergic receptor situated in the postsynaptic dorsal horn of spinalcord. 10 It works by blocking the conductance of C & A fibres, increases the potassium ion in isolated neurons in - vitro and intensifies conductance block of local anaesthetics. 11 The aim of our study was to compare the quality and duration of analgesia, to assess the hemodynamic effects and to assess the incidence of side effects (sedation, post - operative nausea and vomiting when 2% lignocaine was used alone and

  18. The influence of hemodynamic forces on biomarkers in the walls of elastase-induced aneurysms in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Kadirvel, Ramanathan; Ding, Yong-Hong; Dai, Daying; Danielson, Mark A.; Lewis, Debra A.; Cloft, Harry J.; Kallmes, David F. [Mayo Clinic College of Medicine, Department of Radiology, Rochester, MN (United States); Zakaria, Hasballah; Robertson, Anne M. [University of Pittsburgh, Department of Mechanical Engineering, Pittsburgh, PA (United States)

    2007-12-15

    Biological and biophysical factors have been shown to play an important role in the initiation, progression, and rupture of intracranial aneurysms. The purpose of this study was to evaluate the association between hemodynamic forces and markers of vascular remodeling in elastase-induced saccular aneurysms in rabbits. Elastase-induced aneurysms were created at the origin of the right common carotid artery in rabbits. Hemodynamic parameters were estimated using computational fluid dynamic simulations based on 3-D-reconstructed models of the vasculature. Expression of matrix metalloproteinases (MMPs), their inhibitors (TIMPs) and markers of vascular remodeling were measured in different spatial regions within the aneurysms. Altered expression of biological markers relative to controls was correlated with the locations of subnormal time-averaged wall shear stress (WSS) but not with the magnitude of pressure. In the aneurysms, WSS was low and expression of biological markers was significantly altered in a time-dependent fashion. At 2 weeks, an upregulation of active-MMP-2, downregulation of TIMP-1 and TIMP-2, and intact endothelium were found in aneurysm cavities. However, by 12 weeks, endothelial cells were absent or scattered, and levels of pro- and active-MMP-2 were not different from those in control arteries, but pro-MMP-9 and both TIMPs were upregulated. These results reveal a strong, spatially localized correlation between diminished WSS and differential expression of biological markers of vascular remodeling in elastase-induced saccular aneurysms. The ability of the wall to function and maintain a healthy endothelium in a low shear environment appears to be significantly impaired by chronic exposure to low WSS. (orig.)

  19. Estimating anthropogenic ecological water stress in the US great lakes region

    Science.gov (United States)

    Anthropocentric water resources management that prioritizes socio-economic growth can cause harmful ecological water stress by depriving aquatic ecosystems of the water needed to sustain habitats. It is important to better understand the impacts of water withdrawal by different economic sectors (e.g...

  20. Comparative study of intravenously administered clonidine and magnesium sulfate on hemodynamic responses during laparoscopic cholecystectomy

    Directory of Open Access Journals (Sweden)

    Nand Kishore Kalra

    2011-01-01

    Full Text Available Background: Both magnesium and clonidine are known to inhibit catecholamine and vasopressin release and attenuate hemodynamic response to pneumoperitoneum. This randomized, double blinded, placebo controlled study has been designed to assess which agent attenuates hemodynamic stress response to pneumoperitoneum better. Materials and Methods: 120 patients undergoing elective laparoscopic cholecystectomy were randomized into 4 groups of 30 each. Group K patients received 50 ml normal saline over a period of 15 min after induction and before pneumoperitoneum, group M patients received 50 mg/kg of magnesium sulfate in normal saline (total volume 50 ml over same time duration. Similarly group C1 patients received 1 μg/kg clonidine and group C2 1.5 μg/kg clonidine respectively in normal saline (total volume 50 ml. Blood pressure and heart rate were recorded before induction (baseline value, at the end of infusions and every 5 min after pneumoperitoneum. Statistical Analysis: Paired t test was used for intra-group comparison and ANOVA for inter-group comparison. Results: Systolic blood pressure was significantly higher in control group as compared to all other groups during pneumoperitoneum. On comparing patients in group M and group C1, no significant difference in systolic BP was found at any time interval. Patients in group C2 showed best control of systolic BP. As compared to group M and group C1, BP was significantly lower at 10, 30 and 40 min post pneumoperitoneum. No significant episodes of hypotension were found in any of the groups. Extubation time and time to response to verbal command like eye opening was significantly longer in group M as compared to other groups. Conclusion: Administration of magnesium sulfate or clonidine attenuates hemodynamic response to pneumoperitoneum. Although magnesium sulfate 50 mg/kg produces hemodynamic stability comparable to clonidine 1 μg/kg, clonidine in doses of 1.5μg/kg blunts the hemodynamic response

  1. Combined Effects of Flow Diverting Strategies and Parent Artery Curvature on Aneurysmal Hemodynamics: A CFD Study.

    Directory of Open Access Journals (Sweden)

    Jinyu Xu

    Full Text Available Flow diverters (FD are increasingly being considered for treating large or giant wide-neck aneurysms. Clinical outcome is highly variable and depends on the type of aneurysm, the flow diverting device and treatment strategies. The objective of this study was to analyze the effect of different flow diverting strategies together with parent artery curvature variations on altering intra-aneurysmal hemodynamics.Four ideal intracranial aneurysm models with different parent artery curvature were constructed. Computational fluid dynamics (CFD simulations of the hemodynamics before and after applying five types of flow diverting strategies (single FD, single FD with 5% and 10% packing density of coils, two FDs with 25% and 50% overlapping rate were performed. Changes in pressure, wall shear stress (WSS, relative residence time (RRT, inflow velocity and inflow volume rate were calculated and compared.Each flow diverting strategy resulted in enhancement of RRT and reduction of normalized mean WSS, inflow volume rate and inflow velocity in various levels. Among them, 50% overlapped FD induced most effective hemodynamic changes in RRT and inflow volume rate. The mean pressure only slightly decreased after treatment. Regardless of the kind of implantation of FD, the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased.Of all flow diverting strategies, overlapping FDs induced most favorable hemodynamic changes. Hemodynamics alterations post treatment were substantially influenced by parent artery curvature. Our results indicate the need of an individualized flow diverting strategy that is tailored for a specific aneurysm.

  2. Regional Mapping of Aortic Wall Stress by Using Deformable, Motion-coherent Modeling based on Electrocardiography-gated Multidetector CT Angiography: Feasibility Study.

    Science.gov (United States)

    Mileto, Achille; Heye, Tobias J; Makar, Ryan A; Hurwitz, Lynne M; Marin, Daniele; Boll, Daniel T

    2016-07-01

    Purpose To investigate the feasibility of deformable, motion-coherent modeling based on electrocardiography-gated multidetector computed tomographic (CT) angiography of the thoracic aorta and to evaluate whether quantifiable information on aortic wall stress as a function of patient-specific cardiovascular parameters can be gained. Materials and Methods For this institutional review board-approved, HIPAA-compliant study, thoracic electrocardiography-gated dual-source multidetector CT angiographic images were used from 250 prospectively enrolled patients (150 men, 100 women; mean age, 79 years). On reconstructed 50-phase CT angiographic images, aortic strain and deformation were determined at seven cardiac and aortic locations. One-way analysis of variance was used by assessing the magnitude for longitudinal and axial strain and axial deformation, as well as time-resolved peak and maxima count for longitudinal strain and axial deformation. Interdependencies between aortic strain and deformation with extracted hemodynamic parameters were evaluated. Results With increasing heart rates, there was a significant decrease in longitudinal strain (P = .009, R(2) = 0.95) and a decrease in the number of longitudinal strain peaks (P < .001, R(2) = 0.79); however, a significant increase in axial deformation (P < .001, R(2) = 0.31) and axial strain (P = .009, R(2) = 0.61) was observed. Increasing aortic blood velocity led to increased longitudinal strain (P = .018, R(2) = 0.42) and longitudinal strain peak counts (P = .011, R(2) = 0.48). Pronounced motion in the longitudinal direction limited motion in the axial plane (P < .019, R(2) = 0.29-0.31). Conclusion The results of this study render a clinical basis and provide proof of principle for the use of deformable, motion-coherent modeling to provide quantitative information on physiological motion of the aorta under various hemodynamic circumstances. (©) RSNA, 2016 Online supplemental material is available for this article.

  3. The effect of coronary revascularization on regional myocardial blood flow as assessed by stress positron emission tomography.

    Science.gov (United States)

    Bober, Robert M; Thompson, Caleb D; Morin, Daniel P

    2017-06-01

    We examined whether regional improvement in stress myocardial blood flow (sMBF) following angiography-guided coronary revascularization depends on the existence of a perfusion defect on positron emission tomography (PET). Percent stenosis on coronary angiography often is the main factor when deciding whether to perform revascularization, but it does not reliably relate to maximum sMBF. PET is a validated method of assessing sMBF. 19 patients (79% M, 65 ± 12 years) underwent PET stress before and after revascularization (17 PCI, 2 CABG). Pre- and post-revascularization sMBF for each left ventricular quadrant (anterior, septal, lateral, and inferior) was stratified by the presence or absence of a baseline perfusion defect on PET and whether that region was revascularized. Intervention was performed on 40 of 76 quadrants. When a baseline perfusion defect existed in a region that was revascularized (n = 26), post-revascularization flow increased by 0.6 ± 0.7 cc/min/g (1.2 ± 0.4 vs 1.7 ± 0.8, P revascularization was performed (n = 14), sMBF did not change significantly (1.7 ± 0.3 vs 1.5 ± 0.4 cc/min/g, P = 0.16). In regions without a defect that were not revascularized (n = 29), sMBF did not significantly change (2.0 ± 0.6 vs 1.9 ± 0.7, P = 0.7). When a stress-induced perfusion defect exists on PET, revascularization improves sMBF in that region. When there is no such defect, sMBF shows no net change, whether or not intervention is performed in that area. PET stress may be useful for identifying areas of myocardium that could benefit from revascularization, and also areas in which intervention is unlikely to yield improvement in myocardial blood flow.

  4. Occupational exposure in hemodynamic; Exposicao ocupacional em hemodinamica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Amanda J.; Fernandes, Ivani M.; Silva, Paula P. Nou; Sordi, Gian Maria A.A.; Carneiro, Janete C.G.G., E-mail: ajsilva@ipen.b, E-mail: imfernandes@ipen.b, E-mail: ppsilva@ipen.b, E-mail: gmsordi@ipen.b, E-mail: janetegc@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-10-26

    This paper has an objective to perform a radiometric survey at a hemodynamic service. Besides, it was intended to evaluate the effective dose of health professionals and to provide data which can contribute with minimization of exposures during the realization of hemodynamic procedure. The radiometric survey was realized in the real environment of work simulating the conditions of a hemodynamic study with a ionization chamber

  5. Arteriovenous fistulas aggravate the hemodynamic effect of vein bypass stenoses

    DEFF Research Database (Denmark)

    Nielsen, Tina G; Djurhuus, Christian Born; Morre-Pedersen, Erik

    1996-01-01

    PURPOSE: The purpose of this study was to assess the impact of arteriovenous fistulas combined with varying degrees of stenosis on distal bypass hemodynamics and Doppler spectral parameters. METHODS: In an in vitro flow model bypass stenoses causing 30%, 55%, and 70% diameter reduction were induced...... hemodynamic conditions of a more severe stenosis. Assessment of the hemodynamic impact of fistulas must be undertaken in the evaluation of in situ vein bypass stenoses....

  6. Social stress in adolescents induces depression and brain-region-specific modulation of the transcription factor MAX.

    Science.gov (United States)

    Resende, L S; Amaral, C E; Soares, R B S; Alves, A S; Alves-Dos-Santos, L; Britto, L R G; Chiavegatto, S

    2016-10-11

    MAX is a conserved constitutive small phosphoprotein from a network of transcription factors that are extensively studied in tumorigenesis and whose functions affect cell proliferation, differentiation and death. Inspired by its higher expression during development and in regions involved in emotional behaviors, we hypothesized its involvement in cerebral changes caused by early-life stress. We studied the effects of repeated social stress during adolescence on behaviors and on MAX and its putative partner MYC. Thirty-day-old C57BL/6 male mice underwent brief daily social defeat stress from an adult aggressor for 21 days. Following social stress episodes and housing in social groups after each defeat, adolescent mice exhibit depressive-like, but not anxiety-like behaviors and show higher MAX nuclear immunoreactivity in hippocampal (HC) but not prefrontal cortical (PFC) neurons. Conversely, MAX immunoreactivity is lower in the striatum (ST) of defeated adolescents. The positive correlation between MAX and MYC levels in the PFC revealed disruptions in both the HC and ST. The changes in MAX protein levels are not due to differential gene expression or protein degradation in those regions, suggesting that posttranscriptional modifications occurred. These findings indicate that repeated, brief social defeat in adolescent male mice, combined with group housing, is a useful protocol to study a subtype of depression that is dissociated from generalized (non-social) anxiety. To our knowledge, this is the first report of an association between dysregulation of the MAX-MYC network in the brain and a behavior, suggesting a novel approach for exploiting the neuroplasticity associated with depression.

  7. Hemodynamic Performance and Thrombogenic Properties of a Superhydrophobic Bileaflet Mechanical Heart Valve

    Science.gov (United States)

    Bark, David L.; Vahabi, Hamed; Bui, Hieu; Movafaghi, Sanli; Moore, Brandon; Kota, Arun K.; Popat, Ketul; Dasi, Lakshmi P.

    2016-01-01

    In this study, we explore how blood-material interactions and hemodynamics are impacted by rendering a clinical quality 25 mm St. Jude Medical Bileaflet mechanical heart valve (BMHV) superhydrophobic (SH) with the aim of reducing thrombo-embolic complications associated with BMHVs. Basic cell adhesion is evaluated to assess blood-material interactions, while hemodynamic performance is analyzed with and without the SH coating. Results show that a SH coating with a receding contact angle (CA) of 160º strikingly eliminates platelet and leukocyte adhesion to the surface. Alternatively, many platelets attach to and activate on pyrolytic carbon (receding CA=47), the base material for BMHVs. We further show that the performance index increases by 2.5% for coated valve relative to an uncoated valve, with a maximum possible improved performance of 5%. Both valves exhibit instantaneous shear stress below 10 N/m2 and Reynolds Shear Stress below 100 N/m2. Therefore, a SH BMHV has the potential to relax the requirement for antiplatelet and anticoagulant drug regimens typically required for patients receiving MHVs by minimizing blood-material interactions, while having a minimal impact on hemodynamics. We show for the first time that SH-coated surfaces may be a promising direction to minimize thrombotic complications in complex devices such as heart valves. PMID:27098219

  8. Stress and atherosclerotic cardiovascular disease.

    Science.gov (United States)

    Inoue, Nobutaka

    2014-01-01

    Recent major advances in medical science have introduced a wide variety of treatments against atherosclerosis-based cardiovascular diseases, which has led to a significant reduction in mortality associated with these diseases. However, atherosclerosis-based cardiovascular disease remains a leading cause of death. Furthermore, progress in medical science has demonstrated the pathogenesis of cardiovascular disease to be complicated, with a wide variety of underlying factors. Among these factors, stress is thought to be pivotal. Several types of stress are involved in the development of cardiovascular disease, including oxidative stress, mental stress, hemodynamic stress and social stress. Accumulating evidence indicates that traditional risk factors for atherosclerosis, including diabetes, hyperlipidemia, hypertension and smoking, induce oxidative stress in the vasculature. Oxidative stress is implicated in the pathogenesis of endothelial dysfunction, atherogenesis, hypertension and remodeling of blood vessels. Meanwhile, mental stress is a well-known major contributor to the development of cardiovascular disease. The cardiovascular system is constantly exposed to hemodynamic stress by the blood flow and/or pulsation, and hemodynamic stress exerts profound effects on the biology of vascular cells and cardiomyocytes. In addition, social stress, such as that due to a lack of social support, poverty or living alone, has a negative impact on the incidence of cardiovascular disease. Furthermore, there are interactions between mental, oxidative and hemodynamic stress. The production of reactive oxygen species is increased under high levels of mental stress in close association with oxidative stress. These stress responses and their interactions play central roles in the pathogenesis of atherosclerosis-based cardiovascular disease. Accordingly, the pathophysiological and clinical implications of stress are discussed in this article.

  9. Post-traumatic Stress Disorder (PTSD) in Children of Conflict Region of Kashmir (India): A Review.

    Science.gov (United States)

    Mushtaq, Raheel; Shah, Tabindah; Mushtaq, Sahil

    2016-01-01

    Post-traumatic stress disorder (PTSD) occurs due to traumatic events. The last two decades have seen various traumatic events in Kashmiri population, which has led to psychological impact on all population, especially children. PTSD is one of the psychiatric disorders occurring after witnessing of traumatic events. A review of literature regarding PTSD in children of Kashmir (India) has been done to assess the prevalence, causes, neurobiology, risk factors and psychiatric co morbidity associated with it.

  10. Psychological Distress and Stressful Life Events in Pediatric Complex Regional Pain Syndrome

    Directory of Open Access Journals (Sweden)

    Julia Wager

    2015-01-01

    Full Text Available BACKGROUND: There is little knowledge regarding the association between psychological factors and complex regional pain syndrome (CRPS in children. Specifically, it is not known which factors precipitate CRPS and which result from the ongoing painful disease.

  11. [Hemodynamic disorders and their correction in the newborn following abdominal surgery].

    Science.gov (United States)

    Grebennikov, V A; Mishina, T P; Stepanenko, S M

    1991-01-01

    Central hemodynamics was studied, using echocardiography and dopplercardiometry in 48 newborn operated on the abdominal organs. General regularities of hemodynamic changes in the first postoperative hours irrespective of the initial type of circulation have been established. Two types of cardiovascular system response to the operation stress are described; an increase and a drop in the cardiac output, which is extremely important for the diagnosis of impaired compensatory-adaptive mechanisms in the newborn. Special attention was paid to the assessment of the adequacy of the infusion therapy. Volume-load test facilitates the diagnosis of latent heart failure. Timely prescription of cardiotonic drugs and differential approach to infusion therapy prevent the onset of circulatory disturbances.

  12. Differential hemodynamic effects of exercise and volume expansion in people with and without heart failure

    DEFF Research Database (Denmark)

    Andersen, Mads Jønsson; Olson, Thomas P; Melenovsky, Vojtech

    2015-01-01

    BACKGROUND:Invasive hemodynamic exercise testing is commonly used in the evaluation of patients with suspected heart failure with preserved ejection fraction (HFpEF) or pulmonary hypertension. Saline loading has been suggested as an alternative provocative maneuver, but the hemodynamic changes...... induced by the 2 stresses have not been compared. METHODS AND RESULTS:Twenty-six subjects (aged, 67±10 years; n=14 HFpEF; n=12 control) underwent right heart catheterization at rest, during supine exercise, and with acute saline loading in a prospective study. Exercise and saline each increased cardiac...... output and pressures in the right atrium, pulmonary artery, and pulmonary capillary wedge positions. Changes in heart rate, blood pressure, rate-pressure product, and cardiac output were greater with exercise compared with saline. In controls subjects, right atrial pressure, pulmonary arterial pressure...

  13. Hemodynamic significance of internal carotid artery disease

    DEFF Research Database (Denmark)

    Schroeder, T

    1988-01-01

    . Examination of periorbital flow direction or oculoplethysmography could be used as a screening procedure. Negative tests most certainly rule out any severe pressure gradient across the stenosis, irrespective of the luminal reduction. A positive result, on the other hand, should be further quantified since...... a significant improvement in baseline flow occur. Flow reserve determined by cerebral vasodilation, however, will improve in most patients with hemodynamic failure. In addition, some patients in the low-pressure group develop marked, but temporary, hyperperfusion after reconstruction of very high grade carotid...

  14. Oxidative Stress in Complex Regional Pain Syndrome (CRPS): No Systemically Elevated Levels of Malondialdehyde, F2-Isoprostanes and 8OHdG in a Selected Sample of Patients

    NARCIS (Netherlands)

    Fischer, S.G.L.; Perez, R.S.G.M.; Nouta, J.; Zuurmond, W.W.A.; Scheffer, P.G.

    2013-01-01

    Exaggerated inflammation and oxidative stress are involved in the pathogenesis of Complex Regional Pain Syndrome (CRPS). However, studies assessing markers for oxidative stress in CRPS patients are limited. In this study, markers for lipid peroxidation (malondialdehyde and F2-isoprostanes) and DNA

  15. Technical solutions to prevent heat stress induced crop growth reduction for three climatic regions in Mexico

    OpenAIRE

    Ooster, van 't, A.; Heuvelink, E.; Loaiza Mejia, V.M.; Henten, van, E.J.

    2008-01-01

    In the last 15 years a significant increase in greenhouse area has occurred in Mexico, from a modest 50 hectares in 1990 to over 2,000 hectares in 2004. The rapid increase in greenhouse area is a result of an attractive export market, USA. Mexican summer midday temperatures are well above crop optimum and cooling is needed if heat stress induced crop growth reduction is to be prevented. The objective of this study was to determine the effectiveness and feasibility of greenhouse cooling system...

  16. Structural alterations in lateral prefrontal, parietal and posterior midline regions of men with chronic posttraumatic stress disorder.

    Science.gov (United States)

    Eckart, Cindy; Stoppel, Christian; Kaufmann, Jörn; Tempelmann, Claus; Hinrichs, Hermann; Elbert, Thomas; Heinze, Hans-Jochen; Kolassa, Iris-Tatjana

    2011-05-01

    So far, the neural network associated with posttraumatic stress disorder (PTSD) has been suggested to mainly involve the amygdala, hippocampus and medial prefrontal cortex. However, increasing evidence indicates that cortical regions extending beyond this network might also be implicated in the pathophysiology of PTSD. We aimed to investigate PTSD-related structural alterations in some of these regions. We enrolled highly traumatized refugees with and without (traumatized controls) PTSD and nontraumatized controls in the study. To increase the validity of our results, we combined an automatic cortical parcellation technique and voxel-based morphometry. In all, 39 refugees (20 with and 19 without PTSD) and 13 controls participated in the study. Participants were middle-aged men who were free of psychoactive substances and consumed little to no alcohol. Patients with PTSD (and to a lesser extent traumatized controls) showed reduced volumes in the right inferior parietal cortex, the left rostral middle frontal cortex, the bilateral lateral orbitofrontal cortex and the bilateral isthmus of the cingulate. An influence of cumulative traumatic stress on the isthmus of the cingulate and the lateral orbitofrontal cortex indicated that, at least in these regions, structural alterations might be associated with repeated stress experiences. Voxel-based morphometry analyses produced largely consistent results, but because of a poorer signal-to-noise ratio, conventional statistics did not reach significance. Although we controlled for several important confounding variables (e.g., sex, alcohol abuse) with our particular sample, this might limit the generalizibility of our data. Moreover, high comorbidity of PTSD and major depression hinders a definite separation of these conditions in our findings. Finally, the results concerning the lateral orbito frontal cortex should be interpreted with caution, as magnetic resonance imaging acquisition in this region is affected by a general

  17. Associations between psychological stress and smoking, drinking, obesity, and high blood pressure in an upper middle-income country in the African region.

    Science.gov (United States)

    Chamik, Tanja; Viswanathan, Bharathi; Gedeon, Jude; Bovet, Pascal

    2017-06-06

    The direction and magnitude of the associations between cardiovascular risk factors (CVRFs) and psychological stress continue to be debated, and no data are available from surveys in the African region. In this study, we examine the associations between CVRFs and psychological stress in the Seychelles, a rapidly developing small island state in the African region. A survey was conducted in 1,240 adults aged 25-64 years representative of the Seychelles. Participants were asked to rank psychological stress that they had experienced during the past 12 months in four domains: work, social life, financial situation, and environment around home. CVRFs (high blood pressure, tobacco use, alcohol drinking, and obesity) were assessed using standard procedures. Psychological stress was associated with age, sex, and socioeconomic status. Overall, there were only few consistent associations between psychological stress and CVRFs, adjusting for age, sex, and socioeconomic status. Social stress was associated with smoking, drinking, and obesity, and there were marginal associations between stress at work and drinking, and between financial stress, and smoking and drinking. Psychological stress was not associated with high blood pressure. These findings suggest that psychological stress should be considered in cardiovascular disease prevention and control strategies. Copyright © 2017 John Wiley & Sons, Ltd.

  18. [Modeling of an influence of indicators of social stress on demographic processes in regions of the Russian Federation].

    Science.gov (United States)

    Burkin, M M; Molchanova, E V

    To assess an impact of indicators of social stress on demographic processes in regions of the Russian Federation using statistical methods. The data of Rosstat «Regions of Russia» and «Health care in Russia» were used as information base. Indicators of about 80 subjects of the Russian Federation (without autonomous areas) for the ten-year period (2005-2014) have been created in the form of the database consisting of the following blocks: medico-demographic situation, level of economic development of the territory and wellbeing of the population, development of social infrastructure, ecological and climatic conditions, scientific researches and innovations. In total, there were about 70 indicators. Panel data for 80 regions of Russia in 10 years, which combine both indicators of spatial type (cross-section data), and information on temporary ranks (time-series data), were used. Various models of regression according to the panel data have been realized: the integrated model of regression (pooled model), regression model with the fixed effects (fixed effect model), regression model with random effects (random effect model). Main demographic indicators (life expectancy, birth rate, mortality from the external reasons) are to a great extent connected with socio-economic factors. Social tension (social stress) caused by transition to market economy plays an important role. The integral assessment of the impact of the average per capita monetary income, incidence of alcoholism and alcoholic psychoses, criminality, sales volume of alcoholic beverages per capita and marriage relations on demographic indicators is presented. Results of modeling allow to define the priority directions in the field of development of mental health and psychotherapeutic services in the regions of the Russian Federation.

  19. Optical monitoring of spinal cord hemodynamics, a feasibility study

    Science.gov (United States)

    Shadgan, Babak; Kwon, Brian K.; Streijger, Femke; Manouchehri, Neda; So, Kitty; Shortt, Katelyn; Cripton, Peter A.; Macnab, Andrew

    2017-02-01

    Background: After an acute traumatic spinal cord injury (SCI), the spinal cord is subjected to ischemia, hypoxia, and increased hydrostatic pressure which exacerbate further secondary damage and neuronal deficit. The purpose of this pilot study was to explore the use of near infrared spectroscopy (NIRS) for non-invasive and real-time monitoring of these changes within the injured spinal cord in an animal model. NIRS is a non-invasive optical technique that utilizes light in the near infrared spectrum to monitor changes in the concentration of tissue chromophores from which alterations in tissues oxygenation and perfusion can be inferred in real time. Methods: A custom-made miniaturized NIRS sensor was developed to monitor spinal cord hemodynamics and oxygenation noninvasively and in real time simultaneously with invasive, intraparenchymal monitoring in a pig model of SCI. The spinal cord around the T10 injury site was instrumented with intraparenchymal probes inserted directly into the spinal cord to measure oxygen pressure, blood flow, and hydrostatic pressure, and the same region of the spinal cord was monitored with the custom-designed extradural NIRS probe. We investigated how well the extradural NIRS probe detected intraparenchymal changes adjacent to the injury site after alterations in systemic blood pressure, global hypoxia, and traumatic injury generated by a weight-drop contusion. Results: The NIRS sensor successfully identified periods of systemic hypoxia, re-ventilation and changes in spinal cord perfusion and oxygenation during alterations of mean arterial pressure and following spinal cord injury. Conclusion: This pilot study indicates that extradural NIRS monitoring of the spinal cord is feasible as a non-invasive optical method to identify changes in spinal cord hemodynamics and oxygenation in real time. Further development of this technique would allow clinicians to monitor real-time physiologic changes within the injured spinal cord during the

  20. Stress Fields Along Okinawa Trough and Ryukyu Arc Inferred From Regional Broadband Moment Tensors

    Science.gov (United States)

    Kubo, A.; Fukuyama, E.

    2001-12-01

    Most shallow earthquakes along Okinawa trough and Ryukyu arc are relatively small (MFREESIA). Lower limit of magnitude of the earthquakes determined becomes 1.5 smaller in M{}w than that of Harvard moment tensors. As a result, we could examine the stress field in more detail than Fournier et al.(2001, JGR, 106, 13751-) did based on surface geology and teleseismic moment tensors. In the NE Okinawa trough, extension axes are oblique to the trough strike, while in SW Okinawa trough, they are perpendicular to the trough. Fault type in SW is normal fault and gradually changes to mixture of normal and strike slip toward NE. In the Ryukyu arc, extension axes are parallel to the arc. Although this feature is not clear in the NW Ryukyu arc, arc parallel extension may be a major property of entire arc. Dominant fault type is normal fault and several strike slips with the same extensional component are included. The volcanic train is located at the edge of arc parallel extension field faced A simple explanation of the arc parallel extension is the response to the opening motion of the Okinawa trough. Another possible mechanism is forearc movement due to oblique subduction which is enhanced in SW. We consider that the Okinawa trough and the Ryukyu arc are independent stress provinces.

  1. Dissecting Regional Variations in Stress Fiber Mechanics in Living Cells with Laser Nanosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, Kandice; Boudreau, Aaron; Bissell, Mina J; Kumar, Sanjay

    2010-03-02

    The ability of a cell to distribute contractile stresses across the extracellular matrix in a spatially heterogeneous fashion underlies many cellular behaviors, including motility and tissue assembly. Here we investigate the biophysical basis of this phenomenon by using femtosecond laser nanosurgery to measure the viscoelastic recoil and cell-shape contributions of contractile stress fibers (SFs) located in specific compartments of living cells. Upon photodisruption and recoil, myosin light chain kinase-dependent SFs located along the cell periphery display much lower effective elasticities and higher plateau retraction distances than Rho-associated kinase-dependent SFs located in the cell center, with severing of peripheral fibers uniquely triggering a dramatic contraction of the entire cell within minutes of fiber irradiation. Image correlation spectroscopy reveals that when one population of SFs is pharmacologically dissipated, actin density flows toward the other population. Furthermore, dissipation of peripheral fibers reduces the elasticity and increases the plateau retraction distance of central fibers, and severing central fibers under these conditions triggers cellular contraction. Together, these findings show that SFs regulated by different myosin activators exhibit different mechanical properties and cell shape contributions. They also suggest that some fibers can absorb components and assume mechanical roles of other fibers to stabilize cell shape.

  2. Stress.

    Science.gov (United States)

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself.

  3. Surgeon-Performed Hemodynamic Transesophageal Echocardiography in the Burn Intensive Care Unit.

    Science.gov (United States)

    Held, Jenny M; Litt, Jeffrey; Kennedy, Jason D; McGrane, Stuart; Gunter, Oliver L; Rae, Lisa; Kahn, Steven A

    2016-01-01

    The use of transesophageal echocardiography (TEE) for resuscitation after burn injury has been reported in small case studies. Conventional TEE is invasive and often requires a subspecialist with a high level of training. The authors report a series of surgeon-performed hemodynamic TEE with an indwelling, less bulky, user-friendly probe. Records of patients treated in a regional burn center who underwent hemodynamic TEE between October 1, 2012 and May 30, 2014 were reviewed. The clinical course of each patient was recorded. All bedside interpretations were retrospectively reviewed for accuracy by a cardiac anesthesiologist. Eleven patients were included in the study. Median age was 68.5 years (interquartile range, 49.5-79.5). Median burn size was 37% TBSA (interquartile range: 16.3-53%). Seven patients were male, and four suffered inhalation injury. The operator's interpretation matched that of the echocardiography technician and cardiac anesthesiologist in all instances. No complications occurred from probe placement. Four patients underwent hemodynamic TEE to determine volume status during resuscitation. Changes in volume status on echocardiography preceded the eventual changes in urine output and vital signs for one patient. Hemodynamic TEE diagnosed cardiogenic shock and was used to titrate inotropes and vasopressors in seven elderly patients. Hemodynamic TEE is a useful adjunct to manage the burn patient who deviates off the expected course, especially if there is a question of cardiac function or volume status. It is less invasive and can be accurately performed by surgical intensivists when transthoracic echo windows are limited. The role of echocardiography in optimizing routine burn resuscitations needs to be further studied.

  4. Patient-Specific Modeling of Intraventricular Hemodynamics

    Science.gov (United States)

    Vedula, Vijay; Marsden, Alison

    2017-11-01

    Heart disease is the one of the leading causes of death in the world. Apart from malfunctions in electrophysiology and myocardial mechanics, abnormal hemodynamics is a major factor attributed to heart disease across all ages. Computer simulations offer an efficient means to accurately reproduce in vivo flow conditions and also make predictions of post-operative outcomes and disease progression. We present an experimentally validated computational framework for performing patient-specific modeling of intraventricular hemodynamics. Our modeling framework employs the SimVascular open source software to build an anatomic model and employs robust image registration methods to extract ventricular motion from the image data. We then employ a stabilized finite element solver to simulate blood flow in the ventricles, solving the Navier-Stokes equations in arbitrary Lagrangian-Eulerian (ALE) coordinates by prescribing the wall motion extracted during registration. We model the fluid-structure interaction effects of the cardiac valves using an immersed boundary method and discuss the potential application of this methodology in single ventricle physiology and trans-catheter aortic valve replacement (TAVR). This research is supported in part by the Stanford Child Health Research Institute and the Stanford NIH-NCATS-CTSA through Grant UL1 TR001085 and partly through NIH NHLBI R01 Grant 5R01HL129727-02.

  5. Regional differences in brain-derived neurotrophic factor levels and dendritic spine density confer resilience to inescapable stress.

    Science.gov (United States)

    Yang, Chun; Shirayama, Yukihiko; Zhang, Ji-Chun; Ren, Qian; Hashimoto, Kenji

    2015-01-07

    In the learned helplessness (LH) paradigm, approximately 35% of rats are resilient to inescapable stress. The roles of brain-derived neurotrophic factor (BDNF) and dendritic spine density in the brain regions of LH (susceptible) and non-LH rats (resilient) were examined. Western blot analysis and Golgi staining were performed. BDNF levels in the medial prefrontal cortex, CA3, and dentate gyrus (DG) were significantly lower in the LH group than in the control and non-LH groups, whereas BDNF levels in the nucleus accumbens (NAc) in the LH group but not the non-LH group were significantly higher than those in the control group. Furthermore, spine density in the prelimbic cortex, CA3, and DG was significantly lower in the LH group than in the control and non-LH groups, although spine density in the NAc was significantly higher in the LH group than in the control and non-LH groups. The results suggest that regional differences in BDNF levels and spine density in rat brain may contribute to resilience to inescapable stress. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  6. Identification of heat risk patterns in the U.S. National Capital Region by integrating heat stress and related vulnerability.

    Science.gov (United States)

    Aubrecht, Christoph; Özceylan, Dilek

    2013-06-01

    The increase in the number and severity of weather extremes (including excessive heat) potentially associated with climate change has highlighted the needs for research into risk assessment and risk reduction measures. Extreme heat events, the focus of this paper, have been consistently reported as the leading cause of weather-related mortality in the United States in recent years. In order to fully understand impact potentials and analyze risk in its individual components both the spatially and temporally varying patterns of heat and the multidimensional characteristics of vulnerability have to be considered. In this paper we present a composite index aggregating these factors to assess heat related risk for the U.S. National Capital Region in 2010. The study reveals how risk patterns are in part driven by the geographic variations of vulnerability, generally showing a clear difference between high-risk urban areas and wide areas of low risk in the suburban and rural environments. This pattern is particularly evident for the core center of the study area around the District of Columbia, which is largely characterized by high index values despite not having experienced the peak of the heat stress as compared to other regions in the metropolitan area. The article aims to set a framework for local-level heat stress risk assessment that can provide valuable input and decision support for climate adaptation planning as well as emergency managers aiming at risk reduction and optimization of resource distribution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. The hemodynamic repercussions of the autonomic modulations in ...

    African Journals Online (AJOL)

    Igor Victorovich Lakhno

    2017-01-16

    Jan 16, 2017 ... Objectives: Idiopathic fetal growth restriction is considered to be associated with hemodynamic abnor- malities. Objectives: The study was aimed to the investigation of the relationship between fetal and maternal autonomic balance, arterial and venous hemodynamic Doppler indices and CTG variables in ...

  8. Bayesian model comparison in nonlinear BOLD fMRI hemodynamics

    DEFF Research Database (Denmark)

    Jacobsen, Danjal Jakup; Hansen, Lars Kai; Madsen, Kristoffer Hougaard

    2008-01-01

    Nonlinear hemodynamic models express the BOLD (blood oxygenation level dependent) signal as a nonlinear, parametric functional of the temporal sequence of local neural activity. Several models have been proposed for both the neural activity and the hemodynamics. We compare two such combined model...

  9. Hemodynamic effects of sevoflurane versus propofol anesthesia for ...

    African Journals Online (AJOL)

    Adele

    opposed to propofol anesthesia might lead to hemodynamic instability during LRFA surgery due to its possible effect on baroreceptors. We, therefore, investigated the hemodynamic profiles of patients undergoing LRFA of liver tumors under either sevoflurane or propofol anesthesia. Purpose. Laparoscopic radiofrequency ...

  10. The hemodynamic repercussions of the autonomic modulations in ...

    African Journals Online (AJOL)

    Objectives: Idiopathic fetal growth restriction is considered to be associated with hemodynamic abnormalities. Objectives: The study was aimed to the investigation of the relationship between fetal and maternal autonomic balance, arterial and venous hemodynamic Doppler indices and CTG variables in case of normal fetal ...

  11. Non-invasive assessment of maternal hemodynamics in early pregnancy

    NARCIS (Netherlands)

    van der Graaf, Anne Marijn; Zeeman, Gerda G.; Groen, Henk; Roberts, Claire; Dekker, Gus A.

    2013-01-01

    Objectives: Non-invasive assessment of maternal hemodynamics in early pregnancy may be promising in evaluating maternal hemodynamic (mal)adaptation to pregnancy. We explored usage of applanation tonometry and Doppler ultrasound for assessment of cardiac output (CO), systemic vascular resistance

  12. Invasive hemodynamic characterization of heart failure with preserved ejection fraction

    DEFF Research Database (Denmark)

    Andersen, Mads Jønsson; Borlaug, Barry A

    2014-01-01

    Recent hemodynamic studies have advanced our understanding of heart failure with preserved ejection fraction (HFpEF). Despite improved pathophysiologic insight, clinical trials have failed to identify an effective treatment for HFpEF. Invasive hemodynamic assessment can diagnose or exclude HFp...

  13. Virtual Water Trade: Revisiting the Assessments to Incorporate Regional Water Stress

    Science.gov (United States)

    Perveen, S.; Puma, M. J.; Troy, T. J.; Browne, M.; Ghosh, M.

    2011-12-01

    Virtual water (VW) refers to the volume of freshwater embedded in the production and shipment of a commodity, which can include agricultural or industrial products, and the trade of commodities can then be viewed as the trade of one region's water resources to another. The premise behind this trade is that countries with a comparative water advantage may choose to export crops, and countries with scarce water resources may focus economic activity on non-water intensive sectors. However, this assumption is not always true given food self-sufficiency policies; water scarce regions often choose to unsustainably mine aquifers for irrigation. Recent studies have shown no correlation between dependency on VW imports and water scarcity for nations, suggesting that politico-economic considerations rather than resource scarcity considerations may dominate the current VW dynamics. Existing VW computations do not take into account water-scarcity value or the full-cost pricing of commodities. This study aims to fill in this gap by focusing on three countries - the United States, India, and Japan - and their production, imports and exports of crop, livestock and industrial commodities. These countries offer three different perspectives on virtual water, with Japan as a net importer of agriculture virtual water and a major industrial nation. The United States, on the other hand, exports significant quantities of grain. India is a developing country with a strong focus on food self-sufficiency. We first quantify the amount of water used in the production of each commodity and then examine the virtual water trade balance for each country, examining the tradeoffs each country has made between agriculture and industrial water use; given that water resources are finite. To examine the interplay between virtual water trade and water scarcity, we focus on two sub-regions, the Ogallala Aquifer in the US and the Punjab region in India, both of which have significant agricultural

  14. Genomic Regions Associated with Tolerance to Freezing Stress and Snow Mold in Winter Wheat

    Directory of Open Access Journals (Sweden)

    Erika B. Kruse

    2017-03-01

    Full Text Available Plants grown through the winter are subject to selective pressures that vary with each year’s unique conditions, necessitating tolerance of numerous abiotic and biotic stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L. associated with tolerance of two of these stresses, freezing temperatures and snow mold—a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars “Finch” and “Eltan” was evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 663 molecular markers was used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct, QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was closely linked with the Fr-A2 (Frost-Resistance A2 locus; its significant association with both traits may have resulted from pleiotropic effects, or from greater low temperature tolerance enabling the plants to better defend against snow mold pathogens. The QTL on 4B associated with freezing tolerance, and the QTL on 6B associated with snow mold tolerance have not been reported previously, and may be useful in the identification of sources of tolerance for these traits.

  15. Genomic Regions Associated with Tolerance to Freezing Stress and Snow Mold in Winter Wheat

    Science.gov (United States)

    Kruse, Erika B.; Carle, Scott W.; Wen, Nuan; Skinner, Daniel Z.; Murray, Timothy D.; Garland-Campbell, Kimberly A.; Carter, Arron H.

    2017-01-01

    Plants grown through the winter are subject to selective pressures that vary with each year’s unique conditions, necessitating tolerance of numerous abiotic and biotic stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L.) associated with tolerance of two of these stresses, freezing temperatures and snow mold—a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars “Finch” and “Eltan” was evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 663 molecular markers was used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL) associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct, QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was closely linked with the Fr-A2 (Frost-Resistance A2) locus; its significant association with both traits may have resulted from pleiotropic effects, or from greater low temperature tolerance enabling the plants to better defend against snow mold pathogens. The QTL on 4B associated with freezing tolerance, and the QTL on 6B associated with snow mold tolerance have not been reported previously, and may be useful in the identification of sources of tolerance for these traits. PMID:28143950

  16. Effects of beta-blockade and atropine on ischemic responses in left ventricular regions subtending coronary stenosis during dobutamine stress echocardiography.

    Science.gov (United States)

    Chen, L; Ma, L; de Prada, V A; Chen, M; Feng, Y J; Waters, D; Gillam, L; Chen, C

    1996-12-01

    This study was designed to examine the effects of a beta-adrenergic blocking agent on the ischemic response to dobutamine stress and to determine the degree to which these effects can be abolished by the addition of atropine. Whether beta-blockade affects the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease has been controversial. In nine pigs, a left anterior descending coronary artery stenosis was created to reduce flow reserve (maximal/rest flow) to 1.1 to 1.9 without baseline regional wall motion abnormalities. This corresponded to a 50% to 90% diameter stenosis. Wall thickening was measured using epicardial echocardiography. Regional lactate production and coronary venous pH were monitored from an adjacent cardiac vein. A standard protocol of dobutamine stress echocardiography was first performed. After normalization of the ischemic abnormalities elicited with this infusion, esmolol was infused at 50 micrograms/kg body weight per min and the dobutamine test was repeated, with 1.0 mg of atropine added at the maximal dobutamine dose. Without esmolol, dobutamine stress induced myocardial ischemia with a reduction in regional wall thickening and lactate production in all nine pigs. Multiple regression analysis revealed that coronary flow per heartbeat (p rate and regional oxygen consumption and altered the relation between coronary flow per heartbeat and regional wall thickening (p heartbeat was demonstrated during baseline dobutamine stress. Beta-blockade shifted this relation so that dobutamine stress-induced myocardial ischemia was attenuated. The mechanisms by which beta-blockade prevents dobutamine-induced ischemia appeared to be mainly through decreases in heart rate and rate of rise in left ventricular pressure, improvement of regional coronary flow per heartbeat and attenuation of regional ischemic lactate production. Adding atropine in conventional doses enhanced the ability of dobutamine stress to induce

  17. Venous hemodynamic changes in lower limb venous disease

    DEFF Research Database (Denmark)

    Lee, Byung Boong; Nicolaides, Andrew N; Myers, Kenneth

    2016-01-01

    There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due...... not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect...... for understanding the complete picture of the patient's disability and response to management by combining ultrasound with hemodynamic studies. Accordingly, at the instigation of Dr Angelo Scuderi, the Union Internationale de Phlebologie (UIP) executive board commissioned a large number of experts to assess all...

  18. Sicily and southern Calabria focal mechanism database: a valuable tool for local and regional stress-field determination

    Directory of Open Access Journals (Sweden)

    Luciano Scarfì

    2013-04-01

    Full Text Available In this work, we present a new catalog of focal mechanisms calculated for earthquakes recorded in Sicily and southern Calabria. It comprises about 300 solutions, for events with magnitudes ranging from 2.7 to 4.8 that occurred from 1999 to 2011. We used P-wave polarities to compute the fault-plane solutions. Two main goals are achieved. For the first, the catalog allows the stress regime and kinematics characterizing the studied area to be depicted at a regional and more local scale. In particular, moving along the tectonic lineament that extends from the Aeolian Islands to the Ionian Sea, there is a change from a regime characterized by sub-horizontal P-axes, ca. NW-SE directed, to an extensive one in the Calabro-Peloritan Arc, where T-axes striking in a NW-SE direction prevail. Our results also show that part of the seismicity is clustered along the main active seismogenic structures, of which the focal mechanisms indicate the kinematics. Finally, in the Etna volcano area, different stress fields act at different depths due to the combination of the regional tectonics, the strong pressurization of the deep magmatic system, and the dynamics of the shallower portion of the volcano. As a second goal, we highlight that the catalog also represents a valuable tool, through the data distribution on the internet, for further studies directed towards improving our understanding of the geodynamic complexity of the region, and for a better characterization of the seismogenic sources.

  19. Very-low-frequency oscillations of cerebral hemodynamics and blood pressure are affected by aging and cognitive load

    NARCIS (Netherlands)

    Vermeij, A.; Abeelen, A.S.S. van den; Kessels, R.P.C.; Beek, A.H. van; Claassen, J.A.H.R.

    2014-01-01

    Spontaneous slow oscillations occur in cerebral hemodynamics and blood pressure (BP), and may reflect neurogenic, metabolic or myogenic control of the cerebral vasculature. Aging is accompanied by a degeneration of the vascular system, which may have consequences for regional cerebral blood flow and

  20. Effects of psychotherapy on regional cerebral blood flow during trauma imagery in patients with post-traumatic stress disorder: a randomized clinical trial

    NARCIS (Netherlands)

    Lindauer, R.J.L.; Booij, J.; Habraken, J.B.A.; van Meijel, E.P.M.; Uylings, H.B.M.; Olff, M.; Carlier, I.V.E.; den Heeten, G.J.; Eck-Smit, B.L.F.; Gersons, B.P.R.

    2008-01-01

    Background. Functional brain-imaging studies in post-traumatic stress disorder (PTSD) have suggested functional alterations in temporal and prefrontal cortical regions. Effects of psychotherapy on these brain regions have not yet been examined. Method. Twenty civilian PTSD out-patients and 15

  1. Regional brain electrical activity in posttraumatic stress disorder after motor vehicle accident.

    Science.gov (United States)

    Rabe, Sirko; Beauducel, André; Zöllner, Tanja; Maercker, Andreas; Karl, Anke

    2006-11-01

    This study examined whether patients with posttraumatic stress disorder (PTSD) related to motor vehicle accidents (MVAs) would show an abnormal pattern of electroencephalographic (EEG) alpha asymmetries, which has been proposed for particular types of anxiety. Patients with PTSD (n = 22) or subsyndromal PTSD (n = 21), traumatized controls without PTSD (non-PTSD with MVA; n = 21), and healthy controls without MVA (n = 23) underwent measurement of EEG activity during baseline and exposure to a neutral, a positive, a negative, and an accident-related picture. Differences in brain asymmetry between groups were observed only during exposure to trauma-related material. PTSD and subsyndromal PTSD patients showed a pattern of enhanced right anterior and posterior activation, whereas non-PTSD with MVA participants showed the opposite pattern. Furthermore, posterior asymmetry in nontraumatized healthy controls varied with gender, with female participants showing a pattern of higher right posterior activation. The results support the hypothesis that symptomatic MVA survivors are characterized by a pattern of right hemisphere activation that is associated with anxious arousal and symptoms of PTSD during processing of trauma-specific information. (c) 2006 APA, all rights reserved.

  2. An Integrative Model of the Cardiovascular System Coupling Heart Cellular Mechanics with Arterial Network Hemodynamics

    Science.gov (United States)

    Kim, Young-Tae; Lee, Jeong Sang; Youn, Chan-Hyun; Choi, Jae-Sung

    2013-01-01

    The current study proposes a model of the cardiovascular system that couples heart cell mechanics with arterial hemodynamics to examine the physiological role of arterial blood pressure (BP) in left ventricular hypertrophy (LVH). We developed a comprehensive multiphysics and multiscale cardiovascular model of the cardiovascular system that simulates physiological events, from membrane excitation and the contraction of a cardiac cell to heart mechanics and arterial blood hemodynamics. Using this model, we delineated the relationship between arterial BP or pulse wave velocity and LVH. Computed results were compared with existing clinical and experimental observations. To investigate the relationship between arterial hemodynamics and LVH, we performed a parametric study based on arterial wall stiffness, which was obtained in the model. Peak cellular stress of the left ventricle and systolic blood pressure (SBP) in the brachial and central arteries also increased; however, further increases were limited for higher arterial stiffness values. Interestingly, when we doubled the value of arterial stiffness from the baseline value, the percentage increase of SBP in the central artery was about 6.7% whereas that of the brachial artery was about 3.4%. It is suggested that SBP in the central artery is more critical for predicting LVH as compared with other blood pressure measurements. PMID:23960442

  3. Modeling of the acute effects of primary hypertension and hypotension on the hemodynamics of intracranial aneurysms.

    Science.gov (United States)

    Sarrami-Foroushani, Ali; Villa-Uriol, Maria-Cruz; Nasr Esfahany, Mohsen; Coley, Stuart C; Di Marco, Luigi Yuri; Frangi, Alejandro F; Marzo, Alberto

    2015-01-01

    Hemodynamics is a risk factor in intracranial aneurysms (IA). Hypertension and pharmacologically induced hypotension are common in IA patients. This study investigates how hypertension and hypotension may influence aneurysmal hemodynamics. Images of 23 IAs at typical locations were used to build patient-specific Computational Fluid Dynamics models. The effects of hypotension and hypertension were simulated through boundary conditions by modulating the normotensive flow and pressure waveforms, in turn produced by a 1D systemic vascular model. Aneurysm location and flow pattern types were used to categorize the influence of hypotension and hypertension on relevant flow variables (velocity, pressure and wall shear stress). Results indicate that, compared to other locations, vertebrobasilar aneurysms (VBA) are more sensitive to flow changes. In VBAs, space-averaged velocity at peak systole increased by 30% in hypertension (16-21% in other locations). Flow in VBAs in hypotension decreased by 20% (10-13% in other locations). Momentum-driven hemodynamic types were also more affected by hypotension and hypertension, than shear-driven types. This study shows how patient-specific modeling can be effectively used to identify location-specific flow patterns in a clinically-relevant study, thus reinforcing the role played by modeling technologies in furthering our understanding of cardiovascular disease, and their potential in future healthcare.

  4. An integrative model of the cardiovascular system coupling heart cellular mechanics with arterial network hemodynamics.

    Science.gov (United States)

    Kim, Young-Tae; Lee, Jeong Sang; Youn, Chan-Hyun; Choi, Jae-Sung; Shim, Eun Bo

    2013-08-01

    The current study proposes a model of the cardiovascular system that couples heart cell mechanics with arterial hemodynamics to examine the physiological role of arterial blood pressure (BP) in left ventricular hypertrophy (LVH). We developed a comprehensive multiphysics and multiscale cardiovascular model of the cardiovascular system that simulates physiological events, from membrane excitation and the contraction of a cardiac cell to heart mechanics and arterial blood hemodynamics. Using this model, we delineated the relationship between arterial BP or pulse wave velocity and LVH. Computed results were compared with existing clinical and experimental observations. To investigate the relationship between arterial hemodynamics and LVH, we performed a parametric study based on arterial wall stiffness, which was obtained in the model. Peak cellular stress of the left ventricle and systolic blood pressure (SBP) in the brachial and central arteries also increased; however, further increases were limited for higher arterial stiffness values. Interestingly, when we doubled the value of arterial stiffness from the baseline value, the percentage increase of SBP in the central artery was about 6.7% whereas that of the brachial artery was about 3.4%. It is suggested that SBP in the central artery is more critical for predicting LVH as compared with other blood pressure measurements.

  5. A 12-week resistance training program elicits positive changes in hemodynamic responses in the elderly

    Directory of Open Access Journals (Sweden)

    Cinthya Campos Salazar

    2009-03-01

    Full Text Available The aim of the study was to determine the effect of a resistance training program in hemodynamic responses and adaptations in 60 yr. old elderly. Volunteers were 60 healthy-elderly who underwent a training program 3 times/wk. for 12 wk. Participants were randomly assigned to either a control group, an exercise group who trained at 30% intensity of 5 maximal repetitions (5RM (30% of 5RM or an exercise group at an intensity of 70% (70% of 5RM. Hemodynamic variables measured were mean arterial pressure (MAP, calculated before and immediately after the training session, and rate pressure product (RPP, estimated once a month and before and after finishing the program. Results indicated that resistance exercise training at 30% and 70% of 5RM, with a total exercise work of 872.7 and 890.9 kg did not elicited cardiovascular risks for the elderly. A 12-wk resistance exercise training reduced the cardiovascular strain as shown by the RPP (~16% and the MAP (~9%, with no adverse effects throughout the program. Unfortunately, all the hemodynamic benefits were reverted 6 days following completion of the program. In conclusion, a healthy elderly population must perform resistance training exercises to significantly reduce the cardiovascular stress. We suggest to conduct further research that looks into different exercise intensities in longer program duration and to determine the mechanisms responsible for the deleterious effects of the detraining by using physiological, biochemical and biomechanical variables.

  6. In vivo measurement of hemodynamic information in stenosed rat blood vessels using X-ray PIV

    Science.gov (United States)

    Park, Hanwook; Park, Jun Hong; Lee, Sang Joon

    2016-11-01

    Measurements of the hemodynamic information of blood flows, especially wall shear stress (WSS), in animal models with circulatory vascular diseases (CVDs) are important to understand the pathological mechanism of CVDs. In this study, X-ray particle image velocimetry (PIV) with high spatial resolution was applied to obtain velocity field information in stenosed blood vessels with high WSS. 3D clips fabricated with a 3D printer were applied to the abdominal aorta of a rat cadaver to induce artificial stenosis in the real blood vessel of an animal model. The velocity and WSS information of blood flows in the stenosed vessel were obtained and compared at various stenosis severities. In vivo measurement was also conducted by fastening a stenotic clip on a live rat model through surgical intervention to reduce the flow rate to match the limited temporal resolution of the present X-ray PIV system. Further improvement of the temporal resolution of the system might be able to provide in vivo measurements of hemodynamic information from animal disease models under physiological conditions. The present results would be helpful for understanding the relation between hemodynamic characteristics and the pathological mechanism in animal CVD models.

  7. Hemodynamic analysis in infants with late-onset circulatory collapse.

    Science.gov (United States)

    Washio, Yosuke; Uchiyama, Atsushi; Nakanishi, Hidehiko; Totsu, Satsuki; Masumoto, Kenichi; Kusuda, Satoshi

    2013-10-01

    Late-onset circulatory collapse (LCC) is a disorder in which blood pressure decreases and oliguria suddenly occurs in preterm infants who have survived the acute stage, leading to shock, without contributing underlying factors. In order to evaluate hemodynamic changes during LCC, the correlation between myocardial functions and organ blood flow was investigated with echography. Seven very-low-birthweight infants were given a diagnosis of LCC during the study period. Cardiovascular and organ flow parameters of the infants were recorded prospectively, once a week, and compared with eight control very-low-birthweight infants with matching gestational age. Echographic study was performed before LCC, at the onset of LCC, and after LCC among infants with LCC. A significant increase in ejection fraction and a significant decrease in end systolic wall stress were observed in infants with the LCC condition. At the same time, the mean blood flow velocity increased significantly in the superior mesenteric artery, while it decreased in the anterior cerebral artery. Systolic blood flow velocity increased and mean velocity was maintained in the renal artery during LCC. LCC is a distributive shock, characterized by a hyperdynamic state and decreased afterload. Echographic examination of organ flow during LCC is useful in understanding the pathophysiology of the disorder. © 2013 The Authors. Pediatrics International © 2013 Japan Pediatric Society.

  8. Mining data from hemodynamic simulations via Bayesian emulation

    Directory of Open Access Journals (Sweden)

    Nair Prasanth B

    2007-12-01

    Full Text Available Abstract Background: Arterial geometry variability is inevitable both within and across individuals. To ensure realistic prediction of cardiovascular flows, there is a need for efficient numerical methods that can systematically account for geometric uncertainty. Methods and results: A statistical framework based on Bayesian Gaussian process modeling was proposed for mining data generated from computer simulations. The proposed approach was applied to analyze the influence of geometric parameters on hemodynamics in the human carotid artery bifurcation. A parametric model in conjunction with a design of computer experiments strategy was used for generating a set of observational data that contains the maximum wall shear stress values for a range of probable arterial geometries. The dataset was mined via a Bayesian Gaussian process emulator to estimate: (a the influence of key parameters on the output via sensitivity analysis, (b uncertainty in output as a function of uncertainty in input, and (c which settings of the input parameters result in maximum and minimum values of the output. Finally, potential diagnostic indicators were proposed that can be used to aid the assessment of stroke risk for a given patient's geometry.

  9. Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.

    Science.gov (United States)

    Alasaari, Jukka S; Lagus, Markus; Ollila, Hanna M; Toivola, Auli; Kivimäki, Mika; Vahtera, Jussi; Kronholm, Erkki; Härmä, Mikko; Puttonen, Sampsa; Paunio, Tiina

    2012-01-01

    Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4) promoter methylation among nurses from high and low work stress environments. Using bisulfite sequencing, we investigated the methylation status of five CpG residues of a CpG-rich region in the promoter of SLC6A4 by comparing female shift working nurses from a high work stress environment (n = 24) to low work stress environment (n = 25). We also analyzed the association of 5-HTTLPR polymorphism at 5' end of SLC6A4. Work stress was assessed by the Karasek's Model and possible signs of burnout or depression were measured by the Maslach Burnout Index General Survey and Beck Depression Index. Methylation levels were assessed by bisulfite sequencing of DNA extracted from peripheral blood leucocytes. Restriction enzyme treatment followed by standard PCR was used to identify 5-HTTLPR genotypes. We found that nurses in the high stress environment had significantly lower promoter methylation levels at all five CpG residues compared to nurses in the low stress environment (pburnout was not significantly associated to methylation levels. However, when mutually adjusted for both, burnout and work stress were significant contributors (p = 0.038 and pdepressed mood in long-term stress.

  10. Saccades and prefrontal hemodynamics in basketball players.

    Science.gov (United States)

    Fujiwara, K; Kiyota, N; Maekawa, M; Kunita, K; Kiyota, T; Maeda, K

    2009-09-01

    We investigated saccade performance and prefrontal hemodynamics in basketball players with different skill levels. Subjects were 27 undergraduate basketball players and 13 non-athlete undergraduates (control group: CON). The players were divided into two groups: those who had played in the National Athletic Meet during high school or played regularly (n=13, elite group: ELI) and those who were bench warmers (n=14, skilled group: SKI). Horizontal eye movement and oxy-, deoxy-, and total-hemoglobin (Hb) concentration in the prefrontal cortex during pro- and anti-saccade were measured using electro-oculography and near-infrared spectroscopy, respectively. Only error rate in anti-saccade was less in ELI (4.8+/-4.0%) than SKI (13.7+/-12.6%) and CON (13.9+/-8.3%) (pbasketball. Georg Thieme Verlag KG Stuttgart.

  11. Induced and spontaneous hemodynamic oscillations in cerebral and extracerebral tissue for coherent hemodynamics spectroscopy

    Science.gov (United States)

    Sassaroli, Angelo; Zang, Xuan; Tgavalekos, Kristen T.; Fantini, Sergio

    2017-02-01

    We report preliminary results of a study for investigating the spatial homogeneity of induced and spontaneous oscillations in the concentration of oxyhemoglobin on the scalp/skull layer of two human subjects. Hemodynamic oscillations were induced by modulation of arterial blood pressure, which triggers the cerebral autoregulation mechanism. Induced hemodynamic oscillations are used in coherent hemodynamics spectroscopy to derive physiological parameters of interest for medical diagnostics. For example, our dedicated mathematical model translates typical near-infrared spectroscopy observables, like the amplitude and phase relationship of the oscillations of oxy- and deoxyhemoglobin concentrations into capillary and venous blood transit times, cutoff frequency of the autoregulation process, and other parameters related to microvascular blood volume. In this study, we focused on the phase relationship between the oscillations of oxyhemoglobin concentrations in three optical channels, two of which feature a short (5 mm) source-detector separation (sampling the scalp/skull only) and the third one features a long (30 mm) source-detector separation (sampling both extracerebral and cerebral tissues). The two main goals of the study were: a) to compare the coherence of induced and spontaneous oscillations; b) to assess if induced and spontaneous oscillations may be assumed to be uniform in the extracerebral layer. This was assessed by studying the phase relationship of oscillations in oxyhemoglobin concentration at the two short source-detector separations. About point a) we verified that induced oscillations have a higher incidence of coherence than spontaneous oscillations: 74% for induced oscillations, and 30% for spontaneous oscillations. About point b) the results show an overall trend for both spontaneous and induced oscillations to be homogeneous or "quasi-homogeneous" in the extracerebral tissue; however, we observed cases where a significant non-zero phase

  12. Stress echocardiography with smartphone: real-time remote reading for regional wall motion.

    Science.gov (United States)

    Scali, Maria Chiara; de Azevedo Bellagamba, Clarissa Carmona; Ciampi, Quirino; Simova, Iana; de Castro E Silva Pretto, José Luis; Djordjevic-Dikic, Ana; Dodi, Claudio; Cortigiani, Lauro; Zagatina, Angela; Trambaiolo, Paolo; Torres, Marco R; Citro, Rodolfo; Colonna, Paolo; Paterni, Marco; Picano, Eugenio

    2017-11-01

    The diffusion of smart-phones offers access to the best remote expertise in stress echo (SE). To evaluate the reliability of SE based on smart-phone filming and reading. A set of 20 SE video-clips were read in random sequence with a multiple choice six-answer test by ten readers from five different countries (Italy, Brazil, Serbia, Bulgaria, Russia) of the "SE2020" study network. The gold standard to assess accuracy was a core-lab expert reader in agreement with angiographic verification (0 = wrong, 1 = right). The same set of 20 SE studies were read, in random order and >2 months apart, on desktop Workstation and via smartphones by ten remote readers. Image quality was graded from 1 = poor but readable, to 3 = excellent. Kappa (k) statistics was used to assess intra- and inter-observer agreement. The image quality was comparable in desktop workstation vs. smartphone (2.0 ± 0.5 vs. 2.4 ± 0.7, p = NS). The average reading time per case was similar for desktop versus smartphone (90 ± 39 vs. 82 ± 54 s, p = NS). The overall diagnostic accuracy of the ten readers was similar for desktop workstation vs. smartphone (84 vs. 91%, p = NS). Intra-observer agreement (desktop vs. smartphone) was good (k = 0.81 ± 0.14). Inter-observer agreement was good and similar via desktop or smartphone (k = 0.69 vs. k = 0.72, p = NS). The diagnostic accuracy and consistency of SE reading among certified readers was high and similar via desktop workstation or via smartphone.

  13. Stratification of cerebral hemodynamics of child moyamoya disease using CBF SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawara, Jyoji; Saito, Norihiro; Osato, Toshiaki; Kamiyama, Kenji; Takeda, Rihei; Nakamura, Hirohiko [Nakamura Memorial Hospital, Sapporo (Japan)

    2002-12-01

    In order to make sure the stratification of cerebral hemodynamics of child moyamoya disease, we evaluated {sup 123}I-IMP SPECT before and after surgical revascularization. The aim of this paper is to establish the semiquantitative parameters that can be applied to estimate severity of hemodynamic cerebral ischemia instead of quantitative parameters. Quantitative studies using IMP-autoradiography (ARG) method were performed on thirteen patients to measure resting regional cerebral blood flow (rCBF), and vascular reserve (rVR): (Diamox-activated rCBF/resting rCBF-1) x 100%. Semiquantitative parameters were calculated from the ratio of region of interest (ROI) counts in the anterior cerebral artery (ACA) and middle cerebral artery (MCA) territory to the dominant cerebellum counts (ROI/Ce ratio) at resting and Diamox-activated conditions. From the quantitative study, both mean resting rCBF less than 40 ml/100 g/min and rVR less than 10% could indicate stage 2 hemodynamic cerebral ischemia. The prediction of stage 2 ischemia using semiquantitative parameters (resting ROI/Ce ratio less than 0.9 and Diamox-activated ROI/Ce ratio less than 0.85 in the MCA territory) was not statistically different comparison to the diagnosis using quantitative parameters (using Fisher exact test<0.0001, Sensitivity and specificity were 87.5% and 90.9%, respectively). The ROI/Ce ratio can be utilized as simple parameters instead of quantitative parameters. (author)

  14. Social cognition and prefrontal hemodynamic responses during a working memory task in schizophrenia.

    Science.gov (United States)

    Pu, Shenghong; Nakagome, Kazuyuki; Yamada, Takeshi; Itakura, Masashi; Yamanashi, Takehiko; Yamada, Sayaka; Masai, Mieko; Miura, Akihiko; Yamauchi, Takahira; Satake, Takahiro; Iwata, Masaaki; Nagata, Izumi; Roberts, David L; Kaneko, Koichi

    2016-03-01

    Social cognition is an important determinant of functional impairment in schizophrenia, but its relationship with the prefrontal functional abnormalities associated with the condition is still unclear. The present study aimed to explore the relationship between social cognition and prefrontal function in patients with schizophrenia using 52-channel near-infrared spectroscopy (NIRS). Twenty-six patients with schizophrenia and 26 age-, gender-, and intelligence quotient-matched healthy controls (HCs) participated in the study. Hemodynamic responses in the prefrontal and superior temporal cortical regions were assessed during a working memory task using NIRS. Social cognition was assessed using the Social Cognition Screening Questionnaire (SCSQ). The observed hemodynamic responses were significantly reduced in the lateral prefrontal cortex (PFC), the frontopolar cortex, and temporal regions in subjects with schizophrenia compared to HCs. Additionally, lateral PFC hemodynamic responses assessed during the working memory task demonstrated a strong positive correlation with the SCSQ theory of mind (ToM) subscale score even after controlling for working memory performance. These results suggest that ToM integrity is closely related to lateral PFC functional abnormalities found in patients with schizophrenia. In addition, this study provides evidence to suggest that NIRS could be used to identify biomarkers of social cognition function in subjects with schizophrenia.

  15. Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Henriksen, Jens Henrik

    1995-01-01

    BACKGROUND & AIMS: Systemic vasodilatation in cirrhosis may lead to hemodynamic alterations with reduced effective blood volume and decreased arterial blood pressure. This study investigates the response of acute volume expansion on hemodynamics and regional blood volumes in patients with cirrhosis...... and in controls. METHODS: Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume...... in patients with either class B or class C. Conversely, the noncentral blood volume increased in patients with class B and C. In both patients and controls, the cardiac output increased and the systemic vascular resistance decreased, whereas the mean arterial blood pressure did not change significantly...

  16. Regional differences in post-traumatic stress symptoms among children after the 2011 tsunami in Higashi-Matsushima, Japan.

    Science.gov (United States)

    Kuwabara, Hitoshi; Araki, Tsuyoshi; Yamasaki, Syudo; Ando, Shuntaro; Kano, Yukiko; Kasai, Kiyoto

    2015-01-01

    On 11 March 2011, a massive undersea earthquake, measuring 9.0 on the Richter scale, caused a tsunami that devastated the shoreline of east Japan. It is estimated that over 20,000 people lost their lives as a result. It is recommended that clinical effort after a tsunami disaster concentrate on a high-impact area rather than cover a large area. However, regional differences in post-traumatic stress symptoms among children after a tsunami disaster are not well clarified. This study evaluated post-traumatic stress symptoms and reported the findings of early-phase screening of 2259 students from Higashi-Matsushima City, Japan, 6 weeks after a tsunami hit the city. The sample was divided into two age groups: elementary school students (n=1102) and junior high school students (n=1157). Of these groups, 289 (26.2%) elementary school students and 123 (10.6%) junior high school students attended the four schools that were located in the area struck by the tsunami; the mortality rate of the area exceeded 4%. We referred to these students as the "high-impact group." The "lower-impact group" consisted of 813 (73.8%) elementary school students and 1034 (89.4%) junior high school students who attended the remaining ten schools. The severity of post-traumatic stress symptoms did not significantly differ between areas with relatively high and low impact. However, among the junior high school students, those attending the school in the highly impacted area showed higher post-traumatic symptoms scores than did the students of the less-impacted area. When planning a mass intervention after a disaster, especially in the early phase when the resources for intervention are not sufficient, it might be useful to consider the degree of age-dependent impact effect. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  17. Morpho-Physiological Responses of Maize to Drought Stress at Different Growth Stages in Northern Semi-Arid Region of Fars

    Directory of Open Access Journals (Sweden)

    R. Hemati

    2014-04-01

    Full Text Available In order to evaluate morpho-physiological responses of hybrid corn KSC750 to water stress at various stages of growth, a field experiment was conducted at the Pasargad region (northwest Fars in 2010. The experiment carried out as a randomized complete block design, with 3 replications. In this study, corn growth period was divided into three phases: the establishment of plant to tasseling (phase I, tasseling to dough development (phase II and dough development to ripening (phase III. Treatments were consisted of control, irrigation cut off after dough development, water stress of 75 percent of FC during vegetative phase and after dough development, water stress of 75 percent of FC during whole growth phase, water stress of 50 percent of FC during vegetative stage and after dough development and water stress of 50 percent of FC during whole growth phase. Results showed that mild drought stress (75% FC at vegetative phase was not significantly effected growth and yield of corn. However, application of drought stress during the whole growth period significantly reduced morphological parameters as well as yield and yield components. Based on these results, flowering and grain filling stages were identified as more sensitive stages to drought stress in corn. Moreover, irrigation cut off after dough development terminated to a satisfactory yield. The results indicated that, overall, under Pasargad region and similar agro climatic conditions, it would be possible to save water to 75 percentage of corn water requirement through application of deficit irrigation after dough development stage.

  18. Inversions for earthquake focal mechanisms and regional stress in the Kachchh Rift Basin, western India: Tectonic implications

    Science.gov (United States)

    Singh, A. P.; Zhao, L.; Kumar, Santsoh; Mishra, Smita

    2016-03-01

    More than a decade after the 2001 MW 7.7 Bhuj earthquake in western India, aftershocks up to MW 5.0 are still continuing around the rupture zone in the Kachchh Rift Basin. Over the years, some surrounding faults in the region have been activated, and a transverse fault generated an MW 5.1 earthquake in 2012. Most of the earthquakes occur in the lower crust at depths between 15 and 35 km. We have determined focal mechanism solutions of 47 earthquakes (MW 3.2-5.1) that were recorded by a 60-station broadband network during 2007-2014 within an area of 50 km radius of the 2001 main shock. South dipping nodal planes in most of the solutions correlate well with the active faults. The earthquakes near the epicenter of the 2001 main shock primarily show reverse-faulting mechanisms. The surrounding earthquakes in the area, however, show predominantly strike-slip mechanisms. The P axes of the earthquakes mostly oriented in north-south, and the T axes in east-west. However, the orientations of the P and T axes exhibit more complexity near the source area of the main shock. Stress field inversion of the solutions yields a dominant north-south compression, which is consistent with the ambient tectonic stress field owing to the northward movement of the Indian Plate with respect to the Eurasian Plate. The geodetic measurements are in reasonable agreement with our results.

  19. Increased Hemodynamic Load in Early Embryonic Stages Alters Myofibril and Mitochondrial Organization in the Myocardium

    Directory of Open Access Journals (Sweden)

    Madeline Midgett

    2017-08-01

    Full Text Available Normal blood flow is essential for proper heart formation during embryonic development, as abnormal hemodynamic load (blood pressure and shear stress results in cardiac defects seen in congenital heart disease (CHD. However, the detrimental remodeling processes that relate altered blood flow to cardiac malformation and defects remain unclear. Heart development is a finely orchestrated process with rapid transformations that occur at the tissue, cell, and subcellular levels. Myocardial cells play an essential role in cardiac tissue maturation by aligning in the direction of stretch and increasing the number of contractile units as hemodynamic load increases throughout development. This study elucidates the early effects of altered blood flow on myofibril and mitochondrial configuration in the outflow tract myocardium in vivo. Outflow tract banding was used to increase hemodynamic load in the chicken embryo heart between Hamburger and Hamilton stages 18 and 24 (~24 h during tubular heart stages. 3D focused ion beam scanning electron microscopy analysis determined that increased hemodynamic load induced changes in the developing myocardium, characterized by thicker myofibril bundles that were more disbursed in circumferential orientation, and mitochondria that organized in large clusters around the nucleus. Proteomic mass-spectrometry analysis quantified altered protein composition after banding that is consistent with altered myofibril thin filament assembly and function, and mitochondrial maintenance and organization. Additionally, pathway analysis of the proteomics data identified possible activation of signaling pathways in response to banding, including the renin-angiotensin system (RAS. Imaging and proteomic data combined indicate that myofibril and mitochondrial arrangement in early embryonic stages is a critical developmental process that when disturbed by altered blood flow may contribute to cardiac malformation and defects.

  20. Toluene effects on oxidative stress in brain regions of young-adult, middle-age, and senescent Brown Norway rats

    Energy Technology Data Exchange (ETDEWEB)

    Kodavanti, Prasada Rao S., E-mail: kodavanti.prasada@epa.gov [Neurotoxicology Branch, Toxicity Assessment Division, NHEERL, ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Royland, Joyce E. [Genetic and Cellular Toxicology Branch, Integrated Systems Toxicology Division, NHEERL, ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Richards, Judy E. [Research Core Unit, NHEERL, ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Besas, Jonathan; MacPhail, Robert C. [Neurotoxicology Branch, Toxicity Assessment Division, NHEERL, ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)

    2011-11-15

    The influence of aging on susceptibility to environmental contaminants is not well understood. To extend knowledge in this area, we examined effects in rat brain of the volatile organic compound, toluene. The objective was to test whether oxidative stress (OS) plays a role in the adverse effects caused by toluene exposure, and if so, if effects are age-dependent. OS parameters were selected to measure the production of reactive oxygen species (NADPH Quinone oxidoreductase 1 (NQO1), NADH Ubiquinone reductase (UBIQ-RD)), antioxidant homeostasis (total antioxidant substances (TAS), superoxide dismutase (SOD), {gamma}-glutamylcysteine synthetase ({gamma}-GCS), glutathione transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GRD)), and oxidative damage (total aconitase and protein carbonyls). In this study, Brown Norway rats (4, 12, and 24 months) were dosed orally with toluene (0, 0.65 or 1 g/kg) in corn oil. Four hours later, frontal cortex, cerebellum, striatum, and hippocampus were dissected, quick frozen on dry ice, and stored at - 80 Degree-Sign C until analysis. Some parameters of OS were found to increase with age in select brain regions. Toluene exposure also resulted in increased OS in select brain regions. For example, an increase in NQO1 activity was seen in frontal cortex and cerebellum of 4 and 12 month old rats following toluene exposure, but only in the hippocampus of 24 month old rats. Similarly, age and toluene effects on glutathione enzymes were varied and brain-region specific. Markers of oxidative damage reflected changes in oxidative stress. Total aconitase activity was increased by toluene in frontal cortex and cerebellum at 12 and 24 months, respectively. Protein carbonyls in both brain regions and in all age groups were increased by toluene, but step-down analyses indicated toluene effects were statistically significant only in 12 month old rats. These results indicate changes in OS parameters with age and toluene exposure

  1. [Contributions to the assessment of hemodynamic status in metabolic syndrome].

    Science.gov (United States)

    Pădure, Livia; Ignat, Ileana Sînziana; Eşanu, Irina; Hurjui, J

    2011-01-01

    The concept of normohemodynamics is based on the fact that the main function of the cardiovascular system is the transport of oxygen. The cardiovascular system is adapting to a new hemodynamic status with every heartbeat. Only one class, called the normohemodynamic state, containing a simultaneous normotension and normodynamic flow, can serve as therapeutic goal. Metabolic syndrome includes a constellation of clinical and biological features that confer an increased cardiovascular risk. Clutter hemodynamic modulators in metabolic syndrome and assessment of hemodynamic status both overall and by its components, open new perspectives in the management of patients with hypertension and metabolic syndrome. In the current study were included 32 patients meeting the criteria for metabolic syndrome and hypertension and 32 controls. Patients were monitored and assessed for the global hemodynamic status and for the modulators of hemodynamics, intravascular volume, vasoactivity and inotropy, respectively. There are no significant differences in the global hemodynamic status between the study group and the control group; in the study group there is a clear weathering of hemodynamic modulators. The improvement of these factors opens a new perspective in the global cardiovascular assessment and therapeutic directions.

  2. Congenital heart malformations induced by hemodynamic altering surgical interventions

    Directory of Open Access Journals (Sweden)

    Madeline eMidgett

    2014-08-01

    Full Text Available Embryonic heart formation results from a dynamic interplay between genetic and environmental factors. Blood flow during early embryonic stages plays a critical role in heart development, as interactions between flow and cardiac tissues generate biomechanical forces that modulate cardiac growth and remodeling. Normal hemodynamic conditions are essential for proper cardiac development, while altered blood flow induced by surgical manipulations in animal models result in heart defects similar to those seen in humans with congenital heart disease. This review compares the altered hemodynamics, changes in tissue properties, and cardiac defects reported after common surgical interventions that alter hemodynamics in the early chick embryo, and shows that interventions produce a wide spectrum of cardiac defects. Vitelline vein ligation and left atrial ligation decrease blood pressure and flow; and outflow tract banding increases blood pressure and flow velocities. These three surgical interventions result in many of the same cardiac defects, which indicate that the altered hemodynamics interfere with common looping, septation and valve formation processes that occur after intervention and that shape the four-chambered heart. While many similar defects develop after the interventions, the varying degrees of hemodynamic load alteration among the three interventions also result in varying incidence and severity of cardiac defects, indicating that the hemodynamic modulation of cardiac developmental processes is strongly dependent on hemodynamic load.

  3. Uncertainty propagation of phase contrast-MRI derived inlet boundary conditions in computational hemodynamics models of thoracic aorta.

    Science.gov (United States)

    Bozzi, Silvia; Morbiducci, Umberto; Gallo, Diego; Ponzini, Raffaele; Rizzo, Giovanna; Bignardi, Cristina; Passoni, Giuseppe

    2017-08-01

    This study investigates the impact that uncertainty in phase contrast-MRI derived inlet boundary conditions has on patient-specific computational hemodynamics models of the healthy human thoracic aorta. By means of Monte Carlo simulations, we provide advice on where, when and how, it is important to account for this source of uncertainty. The study shows that the uncertainty propagates not only to the intravascular flow, but also to the shear stress distribution at the vessel wall. More specifically, the results show an increase in the uncertainty of the predicted output variables, with respect to the input uncertainty, more marked for blood pressure and wall shear stress. The methodological approach proposed here can be easily extended to study uncertainty propagation in both healthy and pathological computational hemodynamic models.

  4. Focal mechanisms in the southern Aegean from temporary seismic networks – implications for the regional stress field and ongoing deformation processes

    Directory of Open Access Journals (Sweden)

    W. Friederich

    2014-05-01

    Full Text Available The lateral variation of the stress field in the southern Aegean plate and the subducting Hellenic slab is determined from recordings of seismicity obtained with the CYCNET and EGELADOS networks in the years from 2002 to 2007. First motions from 7000 well-located microearthquakes were analysed to produce 540 well-constrained focal mechanisms. They were complemented by another 140 derived by waveform matching of records from larger events. Most of these earthquakes fall into 16 distinct spatial clusters distributed over the southern Aegean region. For each cluster, a stress inversion could be carried out yielding consistent estimates of the stress field and its spatial variation. At crustal levels, the stress field is generally dominated by a steeply dipping compressional principal stress direction except in places where coupling of the subducting slab and overlying plate come into play. Tensional principal stresses are generally subhorizontal. Just behind the forearc, the crust is under arc-parallel tension whereas in the volcanic areas around Kos, Columbo and Astypalea tensional and intermediate stresses are nearly degenerate. Further west and north, in the Santorini–Amorgos graben and in the area of the islands of Mykonos, Andros and Tinos, tensional stresses are significant and point around the NW–SE direction. Very similar stress fields are observed in western Turkey with the tensional axis rotated to NNE–SSW. Intermediate-depth earthquakes below 100 km in the Nisyros region indicate that the Hellenic slab experiences slab-parallel tension at these depths. The direction of tension is close to east–west and thus deviates from the local NW-oriented slab dip presumably owing to the segmentation of the slab. Beneath the Cretan sea, at shallower levels, the slab is under NW–SE compression. Tensional principal stresses in the crust exhibit very good alignment with extensional strain rate principal axes derived from GPS velocities except

  5. Seismicity, focal mechanisms, and stress distribution in the Tres Virgenes volcanic and geothermal region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Victor; Munguia, Luis [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico)

    2006-01-15

    In October 1993 we carried out a seismic monitoring in the Tres Virgenes volcanic region in order to record the background seismicity associated with the volcanic structures, the geothermal field and the tectonic features of the area. Hypocenters for 257 microearthquakes were located in the volcanic edifices and along the northwest right-lateral, strike-slip La Virgen fault. Focal depths range from close to the Earth surface to about 8 km. Shallow depths occur mainly in the volcanic edifices. Deeper seismic events occurred outside the volcanic area. The duration magnitudes of the located microearthquakes range between 1 and 3. The Vp/Vs ratio and the low-Q values estimated suggest heterogeneous material properties in the volcanic structures mainly toward the El Azufre fault and the El Aguajito Caldera, where hydrothermal activity has been reported. The P- and T-axes of focal mechanisms for 90 microearthquakes suggest that the region is under N-S compression and E-W extension, in agreement with the regional tectonic stress field of the NW-SE right-lateral strike-slip transform fault system of the Gulf of California. [Spanish] En octubre de 1993 se llevo a cabo un monitoreo sismico en la region volcanica Las Tres Virgenes con el proposito de registrar la actividad sismica asociada a las estructuras volcanicas, al campo geotermico y a la tectonica local. Se localizaron 257 microsismos con hipocentros en los edificios volcanicos y a lo largo de la falla de rumbo, lateral derecha conocida como falla La Virgen. La profundidad focal de los sismos varia desde los muy cercanos a la superficie de la Tierra hasta los 8 km. Las profundidades someras ocurren principalmente en los edificios volcanicos. Los sismos mas profundos ocurren fuera del area volcanica. La magnitud de duracion de los microsismos localizados varia entre 1 y 3. La razon Vp/Vs y los valores bajos de Q que se estimaron en la zona sugieren un material con propiedades heterogeneas bajo las estructuras

  6. Hemodynamic monitoring in the era of evidence-based medicine.

    Science.gov (United States)

    Saugel, Bernd; Malbrain, Manu L N G; Perel, Azriel

    2016-12-20

    Hemodynamic instability frequently occurs in critically ill patients. Pathophysiological rationale suggests that hemodynamic monitoring (HM) may identify the presence and causes of hemodynamic instability and therefore may allow targeting therapeutic approaches. However, there is a discrepancy between this pathophysiological rationale to use HM and a paucity of formal evidence (as defined by the strict criteria of evidence-based medicine (EBM)) for its use. In this editorial, we discuss that this paucity of formal evidence that HM can improve patient outcome may be explained by both the shortcomings of the EBM methodology in the field of intensive care medicine and the shortcomings of HM itself.

  7. Response of broomcorn millet (Panicum miliaceum L. genotypes from semiarid regions of China to salt stress

    Directory of Open Access Journals (Sweden)

    Minxuan Liu

    2015-02-01

    Full Text Available Salt tolerance of crops is becoming more and more important, owing to the constant increase of salinity in arid and semi-arid regions. Broomcorn millet (Panicum miliaceum L., generally considered tolerant to salinity, can be an alternative crop for salt affected areas. To assess genotypic variation for vegetative-stage salinity tolerance, 195 broomcorn millet accessions from a core collection were evaluated for germination percentage, shoot length, and root length during germination in 8 mL of deionized water (control or 8 mL of a 120 mmol L− 1 salt solution (treatment. Six genotypes with different levels of salt tolerance were selected based on the growth parameters and ion concentrations in plant at the seedling stage and used for confirmation of the initial salinity response. Substantial variation for salinity tolerance was found on the basis of salt damage index [(germination percentage under control − germination percentage under salinity / germination percentage under control × 100, SDI] and 39 accessions exhibited strong salt tolerance with SDI lower than 20%. The salt tolerance performance of the genotypes was generally consistent across experiments. In the seedling growth study, seedling number, root length and belowground biomass were adversely affected (showing more than 70%, 50%, and 32% reduction, respectively in sensitive genotypes compared to tolerant genotypes (35%, 31%, and 3% reduction, respectively under 160 mmol L− 1 NaCl treatment. In general, whole-plant salinity tolerance was associated with increased Na+ concentration and Na+/K+ ratio, and salt-tolerant genotypes often had higher root and lower shoot Na+ concentration than sensitive ones. Na+ concentration in root was closely related to salt tolerance and may be considered as a selection criterion for screening salt tolerance of broomcorn millet at the seedling or vegetative stages.

  8. Job stress and burnout in hospital employees: comparisons of different medical professions in a regional hospital in Taiwan

    Science.gov (United States)

    Chou, Li-Ping; Li, Chung-Yi; Hu, Susan C

    2014-01-01

    Objectives To explore the prevalence and associated factors of burnout among five different medical professions in a regional teaching hospital. Design Cross-sectional study. Setting Hospital-based survey. Participants A total of 1329 medical professionals were recruited in a regional hospital with a response rate of 89%. These voluntary participants included 101 physicians, 68 physician assistants, 570 nurses, 216 medical technicians and 374 administrative staff. Primary and secondary outcome measures Demographic data included gender, age, level of education and marital status, and work situations, such as position, work hours and work shifts, were obtained from an electronic questionnaire. Job strain and burnout were measured by two validated questionnaires, the Chinese version of the Job Content Questionnaire and the Copenhagen Burnout Inventory. Results Among the five medical professions, the prevalence of high work-related burnout from highest to lowest was nurses (66%), physician assistants (61.8%), physicians (38.6%), administrative staff (36.1%) and medical technicians (31.9%), respectively. Hierarchical regression analysis indicated that job strain, overcommitment and low social support explained the most variance (32.6%) of burnout. Conclusions Physician assistant is an emerging high burnout group; its severity is similar to that of nurses and far more than that of physicians, administrative staff and medical technicians. These findings may contribute to the development of feasible strategies to reduce the stress which results in the burnout currently plaguing most hospitals in Taiwan. PMID:24568961

  9. How a replication origin and matrix attachment region accelerate gene amplification under replication stress in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Shun-suke Tanaka

    Full Text Available The gene amplification plays a critical role in the malignant transformation of mammalian cells. The most widespread method for amplifying a target gene in cell culture is the use of methotrexate (Mtx treatment to amplify dihydrofolate reductase (Dhfr. Whereas, we found that a plasmid bearing both a mammalian origin of replication (initiation region; IR and a matrix attachment region (MAR was spontaneously amplified in mammalian cells. In this study, we attempted to uncover the underlying mechanism by which the IR/MAR sequence might accelerate Mtx induced Dhfr amplification. The plasmid containing the IR/MAR was extrachromosomally amplified, and then integrated at multiple chromosomal locations within individual cells, increasing the likelihood that the plasmid might be inserted into a chromosomal environment that permits high expression and further amplification. Efficient amplification of this plasmid alleviated the genotoxicity of Mtx. Clone-based cytogenetic and sequence analysis revealed that the plasmid was amplified in a chromosomal context by breakage-fusion-bridge cycles operating either at the plasmid repeat or at the flanking fragile site activated by Mtx. This mechanism explains how a circular molecule bearing IR/MAR sequences of chromosomal origin might be amplified under replication stress, and also provides insight into gene amplification in human cancer.

  10. Brain responses to chronic social defeat stress: effects on regional oxidative metabolism as a function of a hedonic trait, and gene expression in susceptible and resilient rats.

    Science.gov (United States)

    Kanarik, Margus; Alttoa, Aet; Matrov, Denis; Kõiv, Kadri; Sharp, Trevor; Panksepp, Jaak; Harro, Jaanus

    2011-01-01

    Chronic social defeat stress, a depression model in rats, reduced struggling in the forced swimming test dependent on a hedonic trait-stressed rats with high sucrose intake struggled less. Social defeat reduced brain regional energy metabolism, and this effect was also more pronounced in rats with high sucrose intake. A number of changes in gene expression were identified after social defeat stress, most notably the down-regulation of Gsk3b and Map1b. The majority of differences were between stress-susceptible and resilient rats. Conclusively, correlates of inter-individual differences in stress resilience can be identified both at gene expression and oxidative metabolism levels. Copyright © 2010 Elsevier B.V. and ECNP. All rights reserved.

  11. On the effect of shear thinning rheology on hemodynamic characteristics in basilar tip aneurysms with implication of two distinct flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Wook [Univ. of Ulsan, Ulsan (Korea, Republic of)

    2012-10-15

    Intra aneurysmal hemodynamics such as wall shear stress and complex flow structures have been implicated as one of the important factors on the growth and risk of rupture of an aneurysm. In this study, the sensitivity of intra-aneurysmal blood flow dynamics to the shear thinning rheological model is investigated by using the idealized geometries of a basilar tip aneurysm with two representative anterior posterior (AP) tilting angles (2.deg. and 30.deg.). By choice of different rheological models, time averaged hemodynamic factors such as wall shear stress, oscillatory shear index and relative residence time exhibited only minor effects. However, highly unstable flow present in idealized aneurysm model with 2 .deg. AP tilting angle facilitated an evident change in the instantaneous local flow dynamics with a considerable increase in effective viscosity. Nevertheless, the distinct hemodynamic phenotype, which characterizes the gross intraaneurysmal flow pattern, was independent of the choice of rheological model. This result suggests that the shear thinning viscous effect is of secondary importance in the gross hemodynamics in a basilar tip aneurysm but is appreciably enhanced on the instantaneous hemodynamics with unstable complex flow structures.

  12. Journal of Clinical Monitoring and Computing 2017 end of year summary: cardiovascular and hemodynamic monitoring.

    Science.gov (United States)

    Saugel, Bernd; Bendjelid, Karim; Critchley, Lester A H; Scheeren, Thomas W L

    2018-02-26

    Hemodynamic monitoring provides the basis for the optimization of cardiovascular dynamics in intensive care medicine and anesthesiology. The Journal of Clinical Monitoring and Computing (JCMC) is an ideal platform to publish research related to hemodynamic monitoring technologies, cardiovascular (patho)physiology, and hemodynamic treatment strategies. In this review, we discuss selected papers published on cardiovascular and hemodynamic monitoring in the JCMC in 2017.

  13. Placental and fetal hemodynamics after labetalol or pindolol in a sheep model of increased placental vascular resistance and maternal hypertension.

    Science.gov (United States)

    Erkinaro, Tiina; Kavasmaa, Tomi; Ylikauma, Laura; Mäkikallio, Kaarin; Haapsamo, Mervi; Acharya, Ganesh; Ohtonen, Pasi; Alahuhta, Seppo; Räsänen, Juha

    2009-08-01

    We investigated the effects of labetalol and pindolol on uterine, placental, and fetal hemodynamics following norepinephrine-induced maternal hypertension in a sheep model of increased placental vascular resistance. Also, we examined fetal and placental hemodynamic responses to acute hypoxemia after antihypertensive medication. Norepinephrine increased maternal heart rate (HR), mean arterial pressure (MAP) and uterine vascular resistance (R(UtA)), and decreased uterine volume blood flow (Q(UtA)). Both labetalol and pindolol decreased maternal HR, MAP, and R(UtA), but did not restore Q(UtA). Fetal MAP was unaffected while fetal HR and placental volume blood flow (Q(UA)) decreased and placental vascular resistance increased. During hypoxemia, which was induced by decreasing maternal inspiratory oxygen fraction, all these parameters remained unchanged in the labetalol group while fetal HR increased and Q(UA) further decreased in the pindolol group. We conclude that labetalol and pindolol may compromise uterine and placental hemodynamics. Hypoxemic stress provokes divergent hemodynamic responses in fetuses exposed to these differently acting adrenoceptor antagonists.

  14. Hemodynamic changes during robotic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Vanlal Darlong

    2012-01-01

    Full Text Available Background: Effect on hemodynamic changes and experience of robot-assisted laparoscopic radical prostatectomy (RALRP in steep Trendelenburg position (45° with high-pressure CO 2 pneumoperitoneum is very limited. Therefore, we planned this prospective clinical trial to study the effect of steep Tredelenburg position with high-pressure CO 2 pneumoperitoneum on hemodynamic parameters in a patient undergoing RALRP using FloTrac/Vigileo™1.10. Methods: After ethical approval and informed consent, 15 patients scheduled for RALRP were included in the study. In the operation room, after attaching standard monitors, the radial artery was cannulated. Anesthesia was induced with fentanyl (2 μg/kg and thiopentone (4-7 mg/kg, and tracheal intubation was facilitated by vecuronium bromide (0.1 mg/kg. The patient′s right internal jugular vein was cannulated and the Pre Sep™ central venous oximetry catheter was connected to it. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide and intermittent boluses of vecuronium. Intermittent positive-pressure ventilation was provided to maintain normocapnea. After CO 2 pneumoperitoneum, position of the patient was gradually changed to 45° Trendelenburg over 5 min. The robot was then docked and the robot-assisted surgery started. Intraoperative monitoring included central venous pressure (CVP, stroke volume (SV, stroke volume variation (SVV, cardiac output (CO, cardiac index (CI and central venous oxygen saturation (ScvO 2 . Results: After induction of anesthesia, heart rate (HR, SV, CO and CI were decreased significantly from the baseline value (P>0.05. SV, CO and CI further decreased significantly after creating pneumoperitoneum (P>0.05. At the 45° Trendelenburg position, HR, SV, CO and CI were significantly decreased compared with baseline. Thereafter, CO and CI were persistently low throughout the 45° Trendelenburg position (P=0.001. HR at 20 min and 1 h, SV and mean arterial blood pressure

  15. Meta-Analysis of Stress Myocardial Perfusion Imaging

    Science.gov (United States)

    2017-06-06

    Coronary Disease; Echocardiography; Fractional Flow Reserve, Myocardial; Hemodynamics; Humans; Magnetic Resonance Imaging; Myocardial Perfusion Imaging; Perfusion; Predictive Value of Tests; Single Photon Emission Computed Tomography; Positron Emission Tomography; Multidetector Computed Tomography; Echocardiography, Stress; Coronary Angiography

  16. New approach to intracardiac hemodynamic measurements in small animals

    DEFF Research Database (Denmark)

    Eskesen, Kristian; Olsen, Niels T; Dimaano, Veronica L

    2012-01-01

    Invasive measurements of intracardiac hemodynamics in animal models have allowed important advances in the understanding of cardiac disease. Currently they are performed either through a carotid arteriotomy or via a thoracotomy and apical insertion. Both of these techniques have disadvantages...

  17. Hemodynamic stability during hemodialysis : A role for vasopressin?

    NARCIS (Netherlands)

    Ettema, Esmee Marlien

    2016-01-01

    Despite technological advances, intradialytic hypotension remains a serious complication for hemodialysis patients. A measure to prevent intradialytic hypotension is the biofeedback system Hemocontrol. The mechanism behind the improved hemodynamic stability with Hemocontrol dialysis is not fully

  18. Automated Assessment of Hemodynamics in the Conjunctival Microvasculature Network.

    Science.gov (United States)

    Khansari, Maziyar M; Wanek, Justin; Felder, Anthony E; Camardo, Nicole; Shahidi, Mahnaz

    2016-02-01

    The conjunctival microcirculation is accessible for direct visualization and quantitative assessment of microvascular hemodynamic properties. Currently available methods to assess hemodynamics in the conjunctival microvasculature use manual or semi-automated algorithms, which can be inefficient for application to a large number of microvessels within the microvascular network. We present an automated image analysis method for measurements of diameter and blood velocity in microvessels. The method was applied to conjunctival microcirculation images acquired in 15 healthy human subjects. Frangi filtering, thresholding, and morphological closing were applied to automatically segment microvessels, while variance filtering was used to detect blood flow. Diameter and blood velocity were measured in arterioles and venules within the conjunctival microvascular network, and blood flow and wall shear rate were calculated. Repeatability and validity of hemodynamic measurements were established. The automated image analysis method allows reliable, rapid and quantitative assessment of hemodynamics in the conjunctival microvascular network and can be potentially applied to microcirculation images of other tissues.

  19. Hemodynamic changes after levothyroxine treatment in subclinical hypothyroidism

    DEFF Research Database (Denmark)

    Faber, J; Petersen, L; Wiinberg, N

    2002-01-01

    In hypothyroidism, lack of thyroid hormones results in reduced cardiac function (cardiac output [CO]), and an increase of systemic vascular resistance (SVR). We speculated whether hemodynamic regulation in subjects with subclinical hypothyroidism (SH) (defined as mildly elevated thyrotropin [TSH...

  20. Hemodynamic effects of sevoflurane versus propofol anesthesia for ...

    African Journals Online (AJOL)

    Adele

    Hemodynamic measurements were undertaken at specific time-points during anesthesia and surgery. Mean arterial pressure (MAP) and heart rate (HR) measured oscillometrically, cardiac index determined with thoracic bioimpedance readings , systemic vascular resistance index, central venous pressure, nasopharyngeal.

  1. Hemodynamic patterns of reflux in primary sapheno-popliteal junction incompetence

    Directory of Open Access Journals (Sweden)

    Massimo Cappelli

    2012-12-01

    Full Text Available Duplex ultrasound investigation (DUI has considerably improved the diagnosis of anatomical venous variations in the popliteal region: however, some pitfalls still remain concerning the hemodynamics of incompetent sapheno-popliteal junctions (SPJs. Aims of this study were to assess the prevalence rates of the hemodynamic patterns of reflux, either diastolic or systolic or both, in a large series of patients with SPJ incompetence, and to analyze the origin of the systolic components of the reflux. Four hundred and fiftythree patients, 83 males and 370 females, mean age 58.0 years±SD 13.8 with primary SPJ incompetence (512 limbs underwent preoperative DUI using the Paranà manoeuvre, a dynamic test able to develop systolic and diastolic pressure gradients through the reflex activation of muscle pumps. Of the 512 incompetent SPJs, 420 showed isolated diastolic reflux, 9 isolated systolic reflux and 83 systolic reflux followed by diastolic reflux. Altogether, 92 SPJs over 512 (18% showed a systolic component of the reflux, which originated from the popliteal vein in 78 cases (15% and from the gastrocnemius veins (GVs in 14 cases (3%. In these latter cases, the short saphenous vein and one or more GVs showed a common trunk. Our findings show that the detection of a systolic component of the reflux in incompetent SPJs is not an uncommon event and suggest that treatment strategy should be differentiated according to the origin of the systolic reflux, given their different hemodynamic behavior.

  2. Comparative hemodynamic effects of three different parenterally administered lipid emulsions in conscious dogs.

    Science.gov (United States)

    Van de Velde, M; Wouters, P F; Rolf, N; Van Aken, H; Vandermeersch, E

    1998-01-01

    To compare the hemodynamic side effects of three structurally different lipid emulsions. Randomized, controlled, prospective animal study. University research laboratory. Six chronically instrumented mongrel dogs. On separate days, all animals were submitted to three different treatments, in a randomized order. After baseline measurements, either a long-chain triglyceride emulsion (treatment 1), a mixed medium-chain triglyceride/long-chain triglyceride emulsion (treatment 2), or an omega3 polyunsaturated fatty acid long-chain triglyceride (PUFA) emulsion (treatment 3) was administered intravenously over 30 mins. Global and regional hemodynamics (sonomicrometry) were recorded for 2 hrs after baseline measurements. Arterial blood gases and plasma concentrations of hemoglobin, triglycerides, total protein, and glucose were recorded for 2 hrs. Long-chain triglycerides did not affect the cardiovascular performance in awake animals. However, medium-chain triglycerides/long-chain triglycerides and omega3 PUFA caused marked increases in systemic vascular resistance (from 1833 +/- 154 to 3277 +/- 163 mm Hg/dynexsec5, p emulsions can cause profound cardiovascular side effects at high doses, depending on their composition. Whereas long-chain triglyceride emulsions have virtually no effects on hemodynamics in normal dogs, medium-chain triglyceride/long-chain triglyceride, and omega3 PUFA emulsions should be used with caution in critically ill patients with compromised cardiovascular function.

  3. Application of near-infrared spectroscopy to measurement of hemodynamic signals accompanying stimulated saliva secretion.

    Science.gov (United States)

    Sato, Hiroki; Obata, Akiko N; Moda, Ichiro; Ozaki, Kazutaka; Yasuhara, Takaomi; Yamamoto, Yukari; Kiguchi, Masashi; Maki, Atsushi; Kubota, Kisou; Koizumi, Hideaki

    2011-04-01

    We aim to test the feasibility of using near-infrared spectroscopy (NIRS) for indirect measurement of human saliva secretion in response to taste stimuli for potential application to organoleptic testing. We use an NIRS system to measure extracranial hemodynamics (Hb-signals around the temples) of healthy participants when taste stimuli are taken in their mouths. First, the Hb-signals and volume of expelled saliva (stimulated by distilled-water or sucrose-solution intake) are simultaneously measured and large Hb-signal changes in response to the taste stimuli (Hb-responses) are found. Statistical analysis show that both the Hb response and saliva volume are larger for the sucrose solution than for the distilled water with a significant correlation between them (r = 0.81). The effects of swallowing on the Hb-signals are investigated. Similar Hb responses, differing from the sucrose solution and distilled water, are obtained even though the participants swallow the mouth contents. Finally, functional magnetic resonance imaging is used to identify possible sources of the Hb signals corresponding to salivation. Statistical analysis indicates similar responses in the extracranial regions, mainly around the middle meningeal artery. In conclusion, the identified correlation between extracranial hemodynamics and the saliva volume suggests that NIRS is applicable to the measurement of hemodynamic signals accompanying stimulated saliva secretion.

  4. Differential acetylation of histone H3 at the regulatory region of OsDREB1b promoter facilitates chromatin remodelling and transcription activation during cold stress.

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    Dipan Roy

    Full Text Available The rice ortholog of DREB1, OsDREB1b, is transcriptionally induced by cold stress and over-expression of OsDREB1b results in increase tolerance towards high salt and freezing stress. This spatio-temporal expression of OsDREB1b is preceded by the change in chromatin structure at the promoter and the upstream region for gene activation. The promoter and the upstream region of OsDREB1b genes appear to be arranged into a nucleosome array. Nucleosome mapping of ∼ 700 bp upstream region of OsDREB1b shows two positioned nucleosomes between -610 to -258 and a weakly positioned nucleosome at the core promoter and the TSS. Upon cold stress, there is a significant change in the nucleosome arrangement at the upstream region with increase in DNaseI hypersensitivity or MNase digestion in the vicinity of cis elements and TATA box at the core promoter. ChIP assays shows hyper-acetylation of histone H3K9 throughout the locus whereas region specific increase was observed in H3K14ac and H3K27ac. Moreover, there is an enrichment of RNA PolII occupancy at the promoter region during transcription activation. There is no significant change in the H3 occupancy in OsDREB1b locus negating the possibility of nucleosome loss during cold stress. Interestingly, cold induced enhanced transcript level of OsDREB1b as well as histone H3 acetylation at the upstream region was found to diminish when stressed plants were returned to normal temperature. The result indicates absolute necessity of changes in chromatin conformation for the transcription up-regulation of OsDREB1b gene in response to cold stress. The combined results show the existence of closed chromatin conformation at the upstream and promoter region of OsDREB1b in the transcription "off" state. During cold stress, changes in region specific histone modification marks promote the alteration of chromatin structure to facilitate the binding of transcription machinery for proper gene expression.

  5. Effects of chronic mild stress on apomorphine induced behavioral sensitization in different brain regions of rats in relation to serotonin change

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    Muhammad Farhan

    2015-11-01

    Full Text Available Background: The impacts of unpredictable stressors have influence on neurochemical and behavioral parameters in laboratory animals. Stress induced behavioral changes particularly those associated with anxiety like behavior may activate topographically organized mesolimbic cortical serotonergic system. This study was designed to investigate the influence of unpredictable stress on behavioral and neurochemical parameters in apomorphine treated rats. Methods: Initially, the animals were divided into two groups as Unstressed and stressed (uncontrollable chronic mild stress or UCMS. Both groups of animals were subdivided into two groups; i.e. saline and apomorphine administrated animals at dose 1.0 mg/kg. Behavioral manipulations was observed by monitoring the locomotor activity and exploratory activity. Neurochemical estimation of 5-hydroxytryptamine (5-HT was done by High performance liquid chromatography (HPLC. Animals were decapitated 24hr post apomorphine injection and different regions of brain (dorsal and ventral striatum, of animals were collected and stored at -70°C. Results: This preclinical study showed that the UCMS induced hypophagia were promoted in apomorphine administrated animals. Apomorphine induced hyperlocomotion were more prominent in unstressed animals than that of stressed groups. It implies that apomorphine is effective in the retrieval from UCMS induced depressive symptoms in rats. Neurochemical study showed decreased level of 5-HT in unstressed animals than stressed animals in response to apomorphine administration. Conclusion: This study, therefore establish the relation between stress and addiction at behavioral as well as neurochemical level to better understand the idea whether intolerable stress promotes addiction.

  6. Regional assimilation of CO2 and δ13C surface data to assess terrestrial biosphere models under drought stress

    Science.gov (United States)

    van der Velde, I. R.; Miller, J. B.; Alden, C. B.; Andrews, A. E.; Schaefer, K. M.; Peters, W.; Tans, P. P.; Vaughn, B. H.; White, J. W. C.

    2016-12-01

    Observed atmospheric carbon dioxide (CO2) and the ratios of its stable isotopologue 13CO2/12CO2 (δ13C) contain unique signals of large-scale drought stress that affect the biosphere. When plants experience physiological stress due to heat and drought at leaf level they respond by closing their stomata. This is a safety mechanism that prevents excessive water loss at the expense of carbon uptake, and it changes the overall water-use efficiency. During photosynthesis, 12CO2 is preferentially assimilated over 13CO2, leaving the atmosphere enriched in 13CO2. Water stress slightly changes the ratio of 13CO2 and 12CO2 molecules being removed from the atmosphere, i.e., a reduction of canopy isotope discrimination (Δ), and its changes are evident in atmospheric δ13C.To improve our understanding of the coupled vegetation-atmosphere system we are developing an ensemble Kalman filter assimilation of high precision measurements of CO2 and δ13C from air samples collected over North America. It uses footprints provided by WRF-STILT that allows for efficient atmospheric transport simulations on a much higher horizontal resolution than with a global Eulerian transport model. To force consistency with atmospheric CO2 and δ13C observations we will optimize regional net terrestrial CO2 exchange (NEE) and Δ from a terrestrial biosphere model. We will carefully evaluate the sensitivity of the optimized parameters to uncertainties in the terrestrial biosphere fluxes, observations, time/space aggregation methods, and boundary conditions. Our main questions are: (i) what signal-to-noise in the data, as interpreted by the model, is large enough to robustly estimate Δ and NEE? and (ii) how do the optimized NEE and Δ that are based on the atmospheric constraint compare with the predicted NEE and Δ that are based on biophysical parameterizations? Our ability to accurately predict the responses of the terrestrial biosphere to changing humidity and soil moisture regimes is currently

  7. Hemodynamic and neuropathological analysis in rats with aluminum trichloride-induced Alzheimer's disease.

    Science.gov (United States)

    Chen, Szu-Ming; Fan, Chi-Chen; Chiue, Ming-Shiuan; Chou, Chi; Chen, Jyh-Horng; Hseu, Ruey-Shyang

    2013-01-01

    Hemodynamic normality is crucial to maintaining the integrity of cerebral vessels and, therefore, preserving the cognitive functions of Alzheimer's disease patients. This study investigates the implications of the hemodynamic changes and the neuropathological diversifications of AlCl3-induced AD. The experimental animals were 8- to 12-wk-old male Wistar rats. The rats were randomly divided into 2 groups: a control group and a (+)control group. Food intake, water intake, and weight changes were recorded daily for 22 wk. Synchronously, the regional cerebral blood flow (rCBF) of the rats with AlCl3-induced AD were measured using magnetic resonance imaging (MRI). The hemorheological parameters were analyzed using a computerized auto-rotational rheometer. The brain tissue of the subjects was analyzed using immunohistological chemical (IHC) staining to determine the beta-amyloid (Aβ) levels. The results of hemodynamic analysis revealed that the whole blood viscosity (WBV), fibrinogen, plasma viscosity and RBC aggregation index (RAI) in (+)control were significantly higher than that of control group, while erythrocyte electrophoresis (EI) of whole blood in (+)control were significantly lower than that of control group. The results of acetylcholinesterase-RBC (AChE-RBC)in the (+)control group was significantly higher than that of the control group. The results also show that the reduction of rCBF in rats with AlCl3-induced AD was approximately 50% to 60% that of normal rats. IHC stain results show that significantly more Aβ plaques accumulated in the hippocampus and cortex of the (+)control than in the control group. The results accentuate the importance of hemorheology and reinforce the specific association between hemodynamic and neuropathological changes in rats with AlCl3-induced AD. Hemorheological parameters, such as WBV and fibrinogen, and AChE-RBC were ultimately proven to be useful biomarkers of the severity and progression of AD patients. In addition, the

  8. Bilirubin, Renal Hemodynamics and Blood Pressure

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    David E. Stec

    2012-02-01

    Full Text Available Bilirubin is generated from the breakdown of heme by heme oxygenase and the reduction of biliverdin by the enzyme biliverdin reductase. Several large population studies have reported a significant inverse correlation between plasma bilirubin levels and the incidence of cardiovascular disease. Protection from cardiovascular disease is also observed in patients with Gilbert’s syndrome which is a disease characterized by mutations in hepatic UGT1A1, the enzyme responsible for the conjugation of bilirubin into the bile. Despite the strong correlation between plasma bilirubin levels and the protection from cardiovascular disease, the mechanism by which increases in plasma bilirubin acts to protect against cardiovascular disease is unknown. Since the chronic antihypertensive actions of bilirubin are likely due to its renal actions, the effects of moderate increases in plasma bilirubin on renal hemodynamics as well as bilirubin’s potential effects on renal tubule function will be discussed in this review. Mechanisms of action as well as the potential for antihypertensive therapies targeting moderate increases in plasma bilirubin levels will also be highlighted.

  9. The role of echocardiography in hemodynamic monitoring.

    Science.gov (United States)

    Boyd, John H; Walley, Keith R

    2009-06-01

    Echocardiography has become more widely available to noncardiologists because of the technological advances in smaller, multipurpose ultrasound units with basic cardiac capabilities. In this review, we discuss the type of clinical information a trained intensivist can hope to obtain from bedside echocardiography and suggest the ways in which this complements traditional hemodynamic monitoring. Following a 10-h hands-on course, intensivists are able to perform and interpret a goal-oriented echocardiogram in approximately 10 min with good accuracy. Bedside echocardiography can aid in determining fluid status and qualitative cardiac ejection fraction, which can then be used immediately to guide therapy. Intensivists can safely and accurately perform goal-oriented echocardiography. Although not yet proven to influence clinical outcome, we suggest that the major utility of echocardiography is for those with distributive or mixed shock in whom target central venous pressure has been achieved without evidence of adequate tissue perfusion. In this subset of patients, echocardiography can aid in selecting those most likely to benefit from further fluid or inotropic support.

  10. Prolonged hemodynamic response during incidental facial emotion processing in inter-episode bipolar I disorder.

    Science.gov (United States)

    Rosenfeld, Ethan S; Pearlson, Godfrey D; Sweeney, John A; Tamminga, Carol A; Keshavan, Matcheri S; Nonterah, Camilla; Stevens, Michael C

    2014-03-01

    This fMRI study examined whether hemodynamic responses to affectively-salient stimuli were abnormally prolonged in remitted bipolar disorder, possibly representing a novel illness biomarker. A group of 18 DSM-IV bipolar I-diagnosed adults in remission and a demographically-matched control group performed an event-related fMRI gender-discrimination task in which face stimuli had task-irrelevant neutral, happy or angry expressions designed to elicit incidental emotional processing. Participants' brain activation was modeled using a "fully informed" SPM5 basis set. Mixed-model ANOVA tested for diagnostic group differences in BOLD response amplitude and shape within brain regions-of-interest selected from ALE meta-analysis of previous comparable fMRI studies. Bipolar-diagnosed patients had a generally longer duration and/or later-peaking hemodynamic response in amygdala and numerous prefrontal cortex brain regions. Data are consistent with existing models of bipolar limbic hyperactivity, but the prolonged frontolimbic response more precisely details abnormalities recognized in previous studies. Prolonged hemodynamic responses were unrelated to stimulus type, task performance, or degree of residual mood symptoms, suggesting an important novel trait vulnerability brain dysfunction in bipolar disorder. Bipolar patients also failed to engage pregenual cingulate and left orbitofrontal cortex-regions important to models of automatic emotion regulation-while engaging a delayed dorsolateral prefrontal cortex response not seen in controls. These results raise questions about whether there are meaningful relationships between bipolar dysfunction of specific ventromedial prefrontal cortex regions believed to automatically regulate emotional reactions and the prolonged responses in more lateral aspects of prefrontal cortex.

  11. Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

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    Reza Mohammadi

    2015-10-01

    Full Text Available Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat (Triticum turgidum L. var. durum entries originating in several countries along with four check varieties were evaluated for biotic stresses: yellow rust (Puccinia striiformis Westendorf f. sp. tritici and wheat stem sawfly (WSS Cephus cinctus Norton (Hymenoptera: Cephidae, and abiotic stresses: cold and drought. The main objectives were to (i quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and (ii characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed. Landraces resistant to each stress were identified and agronomically characterized. Percentage reduction due to the stresses varied from 11.4% (yellow rust to 21.6% (cold stress for 1000-kernel weight (TKW and from 19.9 (yellow rust to 91.9% (cold stress for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

  12. Early nutritional stress impairs development of a song-control brain region in both male and female juvenile song sparrows (Melospiza melodia) at the onset of song learning

    Science.gov (United States)

    MacDonald, Ian F; Kempster, Bethany; Zanette, Liana; MacDougall-Shackleton, Scott A

    2006-01-01

    Birdsong is a sexually selected trait and is often viewed as an indicator of male quality. The developmental stress hypothesis proposes a model by which song could be an indicator; the time during early development, when birds learn complex songs and/or local variants of song, is of rapid development and nutritional stress. Birds that cope best with this stress may better learn to produce the most effective songs. The developmental stress hypothesis predicts that early food restriction should impair development of song-control brain regions at the onset of song learning. We examined the effect of food restriction on song-control brain regions in fledgling (both sexes, 23–26 days old) song sparrows (Melospiza melodia). Food restriction selectively reduced HVC volume in both sexes. In addition, sex differences were evident in all three song-control regions. This study lends further support to a growing body of literature documenting a variety of behavioural, physiological and neural detriments in several songbird species resulting from early developmental stress. PMID:16959649

  13. Consistency between Sweat Rate and Wet Bulb Globe Temperature for the Assessment of Heat Stress of People Working Outdoor in Arid and Semi-arid Regions

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    Hamidreza Heidari

    2018-01-01

    Full Text Available Background: Heat stress is common among workers in arid and semi-arid areas. In order to take every preventive measure to protect exposed workers against heat-related disorders, it is crucial to choose an appropriate index that accurately relates environmental parameters to physiological responses. Objective: To investigate the consistency between 2 heat stress and strain indices, ie, sweat rate and wet bulb globe temperature (WBGT, for the assessment of heat stress of people working outdoor in arid and semi-arid regions in Iran. Methods: During spring and summer, 136 randomly selected outdoor workers were enrolled in this study. Using a defined protocol, the sweat rate of these workers was measured 3 times a day. Simultaneously, the environmental parameters including WBGT index were recorded for each working station. Results: The level of agreement between sweat rate and WBGT was poor (κ<0.2. Based on sweat rate, no case exceeding the reference value was observed during the study. WBGT overestimated the heat stress in outdoor workers compared to sweat rate. Conclusion: It seems that the sweat rate standards may need some modifications related to real condition of work in arid and semi-arid regions in Iran. Moreover, it seems that judging workers solely based on monitoring their sweat rate in such regions, can probably result in underestimation of heat stress.

  14. Computational hemodynamic study of intracranial aneurysms coexistent with proximal artery stenosis

    Science.gov (United States)

    Castro, Marcelo A.; Peloc, Nora L.; Putman, Christopher M.; Cebral, Juan R.

    2012-03-01

    Intracranial aneurysms and artery stenosis are vascular diseases with different pathophysiological characteristics. However, although unusual, aneurysms may coexist in up to 5% of patients with stenotic plaque, according to a previous study. Another study showed that incidental detection of cerebral aneurysm in the same cerebral circulation as the stenotic plaque was less than 2%. Patients with concomitant carotid artery stenosis and unruptured intracranial aneurysms pose a difficult management decision for the physician. Case reports showed patients who died due to aneurysm rupture months after endarterectomy but before aneurysm clipping, while others did not show any change in the aneurysm after plaque removal, having optimum outcome after aneurysm coiling. The purpose of this study is to investigate the intraaneurysmal hemodynamic changes before and after treatment of stenotic plaque. Idealized models were constructed with different stenotic grade, distance and relative position to the aneurysm. Digital removal of the stenotic plaque was performed in the reconstructed model of a patient with both pathologies. Computational fluid dynamic simulations were performed using a finite element method approach. Blood velocity field and hemodynamic forces were recorded and analyzed. Changes in the flow patterns and wall shear stress values and distributions were observed in both ideal and image-based models. Detailed investigation of wall shear stress distributions in patients with both pathologies is required to make the best management decision.

  15. Hemodynamic Study of Flow Remodeling Stent Graft for the Treatment of Highly Angulated Abdominal Aortic Aneurysm

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    Siang Lin Yeow

    2016-01-01

    Full Text Available This study investigates the effect of a novel flow remodeling stent graft (FRSG on the hemodynamic characteristics in highly angulated abdominal aortic aneurysm based on computational fluid dynamics (CFD approach. An idealized aortic aneurysm with varying aortic neck angulations was constructed and CFD simulations were performed on nonstented models and stented models with FRSG. The influence of FRSG intervention on the hemodynamic performance is analyzed and compared in terms of flow patterns, wall shear stress (WSS, and pressure distribution in the aneurysm. The findings showed that aortic neck angulations significantly influence the velocity flow field in nonstented models, with larger angulations shifting the mainstream blood flow towards the center of the aorta. By introducing FRSG treatment into the aneurysm, erratic flow recirculation pattern in the aneurysm sac diminishes while the average velocity magnitude in the aneurysm sac was reduced in the range of 39% to 53%. FRSG intervention protects the aneurysm against the impacts of high velocity concentrated flow and decreases wall shear stress by more than 50%. The simulation results highlighted that FRSG may effectively treat aneurysm with high aortic neck angulations via the mechanism of promoting thrombus formation and subsequently led to the resorption of the aneurysm.

  16. Effects of Electroacupuncture at Auricular Concha Region on the Depressive Status of Unpredictable Chronic Mild Stress Rat Models

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    Ru-Peng Liu

    2013-01-01

    Full Text Available To explore new noninvasive treatment options for depression, this study investigated the effects of electroacupuncture (EA at the auricular concha region (ACR of depression rat models. Depression in rats was induced by unpredictable chronic mild stress (UCMS combined with isolation for 21 days. Eighty male Wistar rats were randomly assigned into four groups: normal, UCMS alone, UCMS with EA-ACR treatment, and UCMS with EA-ear-tip treatment. Rats under inhaled anesthesia were treated once daily for 14 days. The results showed that blood pressure and heart rate were significantly reduced in the EA-ACR group than in the UCMS alone group or the EA-ear-tip group. The open-field test scores significantly decreased in the UCMS alone and EA-ear-tip groups but not in the EA-ACR group. Both EA treatments downregulated levels of plasma cortisol and ACTH in UCMS rats back to normal levels. The present study suggested that EA-ACR can elicit similar cardioinhibitory effects as vagus nerve stimulation (VNS, and EA-ACR significantly antagonized UCMS-induced depressive status in UCMS rats. The antidepressant effect of EA-ACR is possibly mediated via the normalization of the hypothalamic-pituitary-adrenal (HPA axis hyperactivity.

  17. 3-Hydroxykynurenine, an endogenous oxidative stress generator, causes neuronal cell death with apoptotic features and region selectivity.

    Science.gov (United States)

    Okuda, S; Nishiyama, N; Saito, H; Katsuki, H

    1998-01-01

    3-Hydroxykynurenine (3-HK) is a potential endogenous neurotoxin whose increased levels have been described in several neurodegenerative disorders. Here, we characterized in vitro neurotoxicity of 3-HK. Of the tested kynurenine pathway metabolites, only 3-HK, and to a lesser extent 3-hydroxyanthranilic acid, were toxic to primary cultured striatal neurons. 3-HK toxicity was inhibited by various antioxidants, indicating that the generation of reactive oxygen species is essential to the toxicity. 3-HK-induced neuronal cell death showed several features of apoptosis, as determined by the blockade by macromolecule synthesis inhibitors, and by the observation of cell body shrinkage with nuclear chromatin condensation and fragmentation. In addition, 3-HK toxicity was dependent on its cellular uptake via transporters for large neutral amino acids, because uptake inhibition blocked the toxicity. Cortical and striatal neurons were much more vulnerable to 3-HK toxicity than cerebellar neurons, which may be attributable to the differences in transporter activities of these neurons. These results indicate that 3-HK, depending on transporter-mediated cellular uptake and on intracellular generation of oxidative stress, induces neuronal cell death with brain region selectivity and with apoptotic features, which may be relevant to pathology of neurodegenerative disorders.

  18. Transcriptional downregulation of rice rpL32 gene under abiotic stress is associated with removal of transcription factors within the promoter region.

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    Pradipto Mukhopadhyay

    Full Text Available BACKGROUND: The regulation of ribosomal proteins in plants under stress conditions has not been well studied. Although a few reports have shown stress-specific post-transcriptional and translational mechanisms involved in downregulation of ribosomal proteins yet stress-responsive transcriptional regulation of ribosomal proteins is largely unknown in plants. METHODOLOGY/PRINCIPAL FINDINGS: In the present work, transcriptional regulation of genes encoding rice 60S ribosomal protein L32 (rpL32 in response to salt stress has been studied. Northern and RT-PCR analyses showed a significant downregulation of rpL32 transcripts under abiotic stress conditions in rice. Of the four rpL32 genes in rice genome, the gene on chromosome 8 (rpL32_8.1 showed a higher degree of stress-responsive downregulation in salt sensitive rice variety than in tolerant one and its expression reverted to its original level upon withdrawal of stress. The nuclear run-on and promoter:reporter assays revealed that the downregulation of this gene is transcriptional and originates within the promoter region. Using in vivo footprinting and electrophoretic mobility shift assay (EMSA, cis-elements in the promoter of rpL32_8.1 showing reduced binding to proteins in shoots of salt stressed rice seedlings were identified. CONCLUSIONS: The present work is one of the few reports on study of stress downregulated genes. The data revealed that rpL32 gene is transcriptionally downregulated under abiotic stress in rice and that this transcriptional downregulation is associated with the removal of transcription factors from specific promoter elements.

  19. Serotonin Transporter-Linked Polymorphic Region (5-HTTLPR) Genotype and Stressful Life Events Interact to Predict Preschool-Onset Depression: A Replication and Developmental Extension

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    Bogdan, Ryan; Agrawal, Arpana; Gaffrey, Michael S.; Tillman, Rebecca; Luby, Joan L.

    2014-01-01

    Background: Scientific enthusiasm about gene × environment interactions, spurred by the 5-HTTLPR (serotonin transporter-linked polymorphic region) × SLEs (stressful life events) interaction predicting depression, have recently been tempered by sober realizations of small effects and meta-analyses reaching opposing conclusions. These mixed findings…

  20. Exploring the potential impact of implementing carbon capture technologies in fossil fuel power plants on regional European water stress index levels

    NARCIS (Netherlands)

    Schakel, W.B.; Pfister, Stephan; Ramirez, C.A.

    Equipping power plants with carbon capture technology can affect cooling demand and water use. This study has explored the potential impact of large scale deployment of power plants with carbon capture technologies on future regional water stress in Europe. A database including 458 of European

  1. Structural and seismic indications of the elements of recent and present-day stress fields in several epicentral regions of western Tien Shan

    Science.gov (United States)

    Umurzakov, R. A.

    2010-05-01

    This study presents the results of stress field reconstruction for the epicentral zones of large-magnitude earthquakes in some folded-mountain regions of western Tien Shan. Field studies, including geostructural and tectonophysical interpretations, performed for the Talas-Suusamyr, Chatkal-Kurama, Turkestan-Zarafshan, Gissar and Nurata-Kyzylkum regions allow the reconstruction of some regional components of the tectonic stress field. The nearly E-W orientations of the lower-order compressional axes are identified in the Chatkal-Kurama and Turkestan-Zarafshan mountain areas. Detailed structural-dynamical diagrams of several epicentral zones and reconstructions of focal mechanisms of some strong earthquakes are derived from the geostructural data. The coincidence of the present-day stress field manifested in the earthquake sources and the recent stress field derived from the geostructural determinations is revealed. The focal mechanisms of the strong earthquakes in the folded-mountain regions of western Tien Shan relate to the thrust/strike-slip faulting and breakup of large tectonic blocks.

  2. The study on hemodynamic effect of series type LVAD on aortic blood flow pattern: a primary numerical study.

    Science.gov (United States)

    Zhang, Qi; Gao, Bin; Chang, Yu

    2016-12-28

    Left ventricular assist device (LVAD) has become an alternative treatment for end-stage heart failure patients. Series type of LVAD, as a novel LVAD, has attracted more and more attention. The hemodynamic effects of series type LVAD on aortic blood pattern are considered as its important characteristics; however, the precise mechanism of it is still unclear. To clarify the hemodynamic effects of series type LVAD on aortic blood flow pattern, a comparative study on the aortic blood flow pattern and hemodynamic states were carried out numerically for two cases, including series type LVAD support and normal condition. The steady-state computational fluid dynamic (CFD) approach was employed. The blood flow streamline, blood velocity vector and distribution of wall shear stress (WSS) were calculated to evaluate the differences of hemodynamic effects between both conditions. The results demonstrated that the aortic flow pattern under series type LVAD showed significant different from that of normal condition. The strength of aortic swirling flow was significantly enhanced by the series type LVAD support. Meanwhile, the rotating direction of swirling flow under LVAD support was also dominated by the rotating direction of series type LVAD. Moreover, the blood velocity and WSS under LVAD support were also significantly enhanced, compared with that under normal condition. The hemodynamic states, including the aortic swirling flow characteristic, was significantly dominated by LVAD support. Present investigation could provide not only a useful information on the vascular complications caused by LVAD support, but also provide a useful guide for optimal the structure of the series type LVAD.

  3. Effects of 8-week swimming training on carotid arterial stiffness and hemodynamics in young overweight adults.

    Science.gov (United States)

    Yuan, Wen-Xue; Liu, Hai-Bin; Gao, Feng-Shan; Wang, Yan-Xia; Qin, Kai-Rong

    2016-12-28

    Exercise has been found to either reduce or increase arterial stiffness. Land-based exercise modalities have been documented as effective physical therapies to decrease arterial stiffness. However, these land-based exercise modalities may not be suitable for overweight individuals, in terms of risks of joint injury. The purpose of this study was to determine the effects of 8-week swimming training and 4-week detraining on carotid arterial stiffness and hemodynamics in young overweight adults. Twenty young male adults who were overweight were recruited and engaged in 8-week of swimming training and 4-week detraining. Five individuals withdrew due to lack of interest and failure to follow the training protocol. Body Fat Percentage (BFP) and carotid hemodynamic variables were measured on a resting day at the following intervals: baseline, 4 weeks, 8 weeks after swimming training and 4 weeks after detraining. A repeated analysis of variance (ANOVA) was used to assess the differences between baseline and each measurement. When significant differences were detected, Tukey's test for post hoc comparisons was used. Eight-week swimming training at moderate intensity decreased BFP, including the trunk and four extremities. Additionally, the BFP of the right and left lower extremities continued to decrease in these overweight adults 4 weeks after ceasing training. Carotid arterial stiffness decreased, while there were no significant changes in arterial diameters. Blood flow velocity, flow rate, maximal and mean wall shear stress increased, while systolic blood pressure and peripheral resistance decreased. No significant differences existed in minimal wall shear stress and oscillatory shear stress. Eight-week swimming training at moderate intensity exhibited beneficial effects on systolic blood pressure, arterial stiffness and blood supply to the brain in overweight adults. Moreover, maximal and mean wall shear stress increased after training. It is worth noting that these

  4. The Scandinavian multicenter hemodynamic evaluation of the SJM Regent aortic valve

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    Offstad Jon

    2011-12-01

    Full Text Available Abstract Background 112 patients who received small and medium sized St.Jude Regent heart valves (19-25 mm at 7 Scandinavian centers were studied between January 2003 and February 2005 to obtain non-invasive data regarding the hemodynamic performance at rest and during Dobutamine stress echocardiography (DSE testing one year after surgery. Material and methods 46 woman and 66 men, aged 61.8 ± 9.7 (18-75 years, were operated on for aortic regurgitation (17, stenosis (65, or mixed dysfunction (30. Valve sizes were 19 mm (6, 21 mm (33, 23 mm (41, 25 mm (30. Two patients receiving size 27 valves were excluded from the hemodynamic evaluation. Pledgets were used in 100 patients, everted mattress in 66 and simple interrupted sutures in 21. Valve orientation varied and was dependent on the surgeons' choice. 34 patients (30.4% underwent concomitant coronary artery surgery. Results There were two early deaths (1.8% and three late deaths, one because of pancreatic cancer. Late events during follow-up were: non structural dysfunction (1, bleeding (2, thromboembolism (2. At one year follow up 93% of the patients were in NYHA classes 1-2 versus 47.8% preoperatively. Dobutamine stress echocardiography (DSE was performed in a total of 66 and maximal peak stress was reached in 61 patients. During DSE testing, the following statistically significant changes took place: Heart rate increased by 73.0%, cardiac output by 85.5%, left ventriclular ejection fraction by 19.6%, and maximal mean prosthetic transvalvular gradient by 133.8%, whereas the effective orifice area index did not change. Left ventricular mass fell during one year from 215 ± 63 to 197 ± 62 g (p Conclusion The Dobutamine test induces a substantial stress, well suitable for echocardiographic assessment of prosthesis valve function and can be performed in the majority of the patients. The changes in pressure gradients add to the hemodynamic characteristics of the various valve sizes. In our patients

  5. Echocardiographic Evaluation of Hemodynamics in Neonates and Children

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    Yogen Singh

    2017-09-01

    Full Text Available Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by the clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of the urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload and cardiac output. The echocardiography has the ability to provide longitudinal functional assessment in real time, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children. It is indispensable in the management of patients with shock, pulmonary hypertension, and patent ductus arteriosus. The echocardiography is the gold standard diagnostic tool to assess hemodynamic stability in patients with pericardial effusion, cardiac tamponade, and cardiac abnormalities such as congenital heart defects or valvar disorders. The information from echocardiography can be used to provide targeted treatment in intensive care settings such as need of fluid resuscitation versus inotropic support, choosing appropriate inotrope or vasopressor, and in providing specific interventions such as selective pulmonary vasodilators in pulmonary hypertension. The physiological information gathered from echocardiography may help in making timely, accurate, and appropriate diagnosis and providing specific treatment in sick patients. There is no surprise that use of bedside point-of-care echocardiography is rapidly gaining interest among neonatologists and intensivists, and it is now being used in clinical decision making for patients with hemodynamic instability. Like any

  6. Ansys Fluent versus Sim Vascular for 4-D patient-specific computational hemodynamics in renal arteries

    Science.gov (United States)

    Mumbaraddi, Avinash; Yu, Huidan (Whitney); Sawchuk, Alan; Dalsing, Michael

    2015-11-01

    The objective of this clinical-need driven research is to investigate the effect of renal artery stenosis (RAS) on the blood flow and wall shear stress in renal arteries through 4-D patient-specific computational hemodynamics (PSCH) and search for possible critical RASs that significantly alter the pressure gradient across the stenosis by manually varying the size of RAS from 50% to 95%. The identification of the critical RAS is important to understand the contribution of RAS to the overall renal resistance thus appropriate clinical therapy can be determined in order to reduce the hypertension. Clinical CT angiographic data together with Doppler Ultra sound images of an anonymous patient are used serving as the required inputs of the PSCH. To validate the PSCH, we use both Ansys Fluent and Sim Vascular and compare velocity, pressure, and wall-shear stress under identical conditions. Renal Imaging Technology Development Program (RITDP) Grant.

  7. Cerebral hemodynamic responses to seizure in the mouse brain: simultaneous near-infrared spectroscopy-electroencephalography study

    Science.gov (United States)

    Lee, Seungduk; Lee, Mina; Koh, Dalkwon; Kim, Beop-Min; Choi, Jee Hyun

    2010-05-01

    We applied near-infrared spectroscopy (NIRS) and electroencephalography (EEG) simultaneously on the mouse brain and investigated the hemodynamic response to epileptic episodes under pharmacologically driven seizure. γ-butyrolactone (GBL) and 4-aminopyridine (4-AP) were applied to induce absence and tonic-clonic seizures, respectively. The epileptic episodes were identified from the single-channel EEG, and the corresponding hemodynamic changes in different regions of the brain were characterized by multichannel frequency-domain NIRS. Our results are the following: (i) the oxyhemoglobin level increases in the case of GBL-treated mice but not 4-AP-treated mice compared to the predrug state; (ii) the dominant response to each absence seizure is a decrease in deoxyhemolobin; (iii) the phase shift between oxy- and deoxyhemoglobin reduces in GBL-treated mice but no 4-AP-treated mice; and (iv) the spatial correlation of hemodynamics increased significantly in 4-AP-treated mice but not in GBL-treated mice. Our results shows that spatiotemporal tracking of cerebral hemodynamics using NIRS can be successfully applied to the mouse brain in conjunction with electrophysiological recording, which will support the study of molecular, cellular, and network origin of neurovascular coupling in vivo.

  8. The effect of intravenous PACAP38 on cerebral hemodynamics in healthy volunteers

    DEFF Research Database (Denmark)

    Birk, Steffen; Sitarz, John Thomas; Petersen, Kenneth Ahrend

    2007-01-01

    PACAP38 is an endogenous peptide located in trigeminal perivascular nerve fibers in the brain. It reduces neuronal loss and infarct size in animal stroke models and has been proposed a candidate substance for human clinical studies of stroke. The effect on systemic hemodynamics and regional......CBF was measured with SPECT and (133)Xe inhalation and mean blood flow velocity in the middle cerebral artery was measured with transcranial Doppler ultrasonography. End tidal partial pressure of CO(2) (P(et)CO(2)) and vital parameters were recorded throughout the 2 hour study period. PACAP38 decreased rCBF in all...

  9. Stress during a Critical Postnatal Period Induces Region-Specific Structural Abnormalities and Dysfunction of the Prefrontal Cortex via CRF1

    Science.gov (United States)

    Yang, Xiao-Dun; Liao, Xue-Mei; Uribe-Mariño, Andrés; Liu, Rui; Xie, Xiao-Meng; Jia, Jiao; Su, Yun-Ai; Li, Ji-Tao; Schmidt, Mathias V; Wang, Xiao-Dong; Si, Tian-Mei

    2015-01-01

    During the early postnatal period, environmental influences play a pivotal role in shaping the development of the neocortex, including the prefrontal cortex (PFC) that is crucial for working memory and goal-directed actions. Exposure to stressful experiences during this critical period may disrupt the development of PFC pyramidal neurons and impair the wiring and function of related neural circuits. However, the molecular mechanisms of the impact of early-life stress on PFC development and function are not well understood. In this study, we found that repeated stress exposure during the first postnatal week hampered dendritic development in layers II/III and V pyramidal neurons in the dorsal agranular cingulate cortex (ACd) and prelimbic cortex (PL) of neonatal mice. The deleterious effects of early postnatal stress on structural plasticity persisted to adulthood only in ACd layer V pyramidal neurons. Most importantly, concurrent blockade of corticotropin-releasing factor receptor 1 (CRF1) by systemic antalarmin administration (20 μg/g of body weight) during early-life stress exposure prevented stress-induced apical dendritic retraction and spine loss in ACd layer V neurons and impairments in PFC-dependent cognitive tasks. Moreover, the magnitude of dendritic regression, especially the shrinkage of apical branches, of ACd layer V neurons predicted the degree of cognitive deficits in stressed mice. Our data highlight the region-specific effects of early postnatal stress on the structural plasticity of prefrontal pyramidal neurons, and suggest a critical role of CRF1 in modulating early-life stress-induced prefrontal abnormalities. PMID:25403725

  10. Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.

    Directory of Open Access Journals (Sweden)

    Jukka S Alasaari

    Full Text Available Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4 promoter methylation among nurses from high and low work stress environments.Using bisulfite sequencing, we investigated the methylation status of five CpG residues of a CpG-rich region in the promoter of SLC6A4 by comparing female shift working nurses from a high work stress environment (n = 24 to low work stress environment (n = 25. We also analyzed the association of 5-HTTLPR polymorphism at 5' end of SLC6A4. Work stress was assessed by the Karasek's Model and possible signs of burnout or depression were measured by the Maslach Burnout Index General Survey and Beck Depression Index. Methylation levels were assessed by bisulfite sequencing of DNA extracted from peripheral blood leucocytes. Restriction enzyme treatment followed by standard PCR was used to identify 5-HTTLPR genotypes.We found that nurses in the high stress environment had significantly lower promoter methylation levels at all five CpG residues compared to nurses in the low stress environment (p<0.01. There was no significant interaction of 5-HTTLPR genotype and work stress with methylation (p = 0.58. In unadjusted (bivariate analysis, burnout was not significantly associated to methylation levels. However, when mutually adjusted for both, burnout and work stress were significant contributors (p = 0.038 and p<0.0001 respectively to methylation levels.Our findings show that environmental stress is concurrent with decreased methylation of the SLC6A4 promoter. This may lead to increased transcriptional activity of the gene, increased reuptake of serotonin from synaptic clefts, and termination of the activity of serotonin. This could present a possible coping mechanism for environmental stress in humans that could eventually increase risk for disturbed functional

  11. Drought Stress and Plant Density Effects on Yield and Yield Components of Maize KSc 301 Hybrid in Varamin Region

    Directory of Open Access Journals (Sweden)

    P. Jafari

    2012-06-01

    Full Text Available To investigate the effect of drought stress and plant density on yield and yield components of maize KSc 301 hybrid, a two-year study (2007-2008 was carried out in Varamin Agricultural Research Center by using strip split plot randomized based on complete block design in three replications. Four water stress levels (before flowering, during flowering and grain filling stage and no stress were assigned as vertical factor and three plant densities (60, 75 and 90 thousand plants ha-1, were assigned made up of horizontal factor. The effects of water stress and plant density were statistically significant on yield and its components. Water stress at flowering stage reduced the grain yield by 42% compared to the control treatment. Water stress before flowering and grain filling periods, although yield was significantly lower than control but there was no significant difference between treatments. Reduce the number of grains per ear and increased the interval between the pollination of flowers until silking were the main reasons for reduced yield in the treatment of water stress at the flowering stage. Density of 75 thousand plants ha-1 was determined the best density for grain yield. Among the tested density, density of 90 thousand plants ha-1, compared to the control treatment had the greatest reduction in yield (25% reduction. Water stress and plant density interaction was statistically significant at 1% level. The highest and lowest grain yield, respectively, related to the 75 thousand plants ha-1 and without water stress (9100kg ha-1 and water stress at the flowering stage and 90 thousand plants ha-1 (3700 kg ha-1.Water stress at flowering stage, and densities of less than 75 thousand plants ha-1 or higher than 75 thousand plants ha-1 was significantly decreased harvest index. The results showed that the density of 75 thousand plants per hectare and avoid stress, especially at the flowering stage appropriate yields can be expected from hybrid KSc

  12. Changes in hemodynamic parameters and cerebral saturation during supraventricular tachycardia.

    Science.gov (United States)

    Hershenson, Jared A; Ro, Pamela S; Miao, Yongjie; Tobias, Joseph D; Olshove, Vincent; Naguib, Aymen N

    2012-02-01

    Induced supraventricular tachycardia (SVT) during electrophysiology studies (EPS) can be associated with hemodynamic changes. Traditionally, invasive arterial blood pressure has been used for continuous monitoring of these changes. This prospective study evaluated the efficacy of near-infrared spectroscopy (NIRS) monitoring during SVT. The use of NIRS has expanded with evidence of its accuracy and benefit in detecting cerebral hypoperfusion. This study aimed first to determine the hemodynamic changes associated with electrophysiology testing for SVT and second to determine whether the hemodynamic changes are associated with similar changes in the cerebral saturation as determined by NIRS. The study enrolled 30 patients 5-20 years of age with a history of SVT who underwent an EPS. The demographic data included age, gender, weight, height, and type of SVT. Hemodynamic data (invasive blood pressure and heart rate), NIRS, bispectral index (BIS), end-tidal carbon dioxide, and pulse oximetry were collected before and during three episodes of induced SVT. The linear correlation coefficient (r) was measured to calculate the relationship of the changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) to the changes in NIRS values during the SVT episodes. Data from 22 patients were collected. The induction of SVT was associated mainly with a change in SBP and a less prominent change in DBP and MAP from baseline. The changes in hemodynamic status were associated with minimal changes in cerebral saturations, as evidenced by an average absolute change in NIRS of SVT during electrophysiology testing is associated with hemodynamic changes, mainly in SBP. In this study, these hemodynamic changes resulted in a minimal decrease in cerebral perfusion, as evidenced by minimal changes in the cerebral saturation measured by NIRS (0.7% from baseline). Although the changes in the cerebral saturation were minimal, these changes were

  13. Effects of seasonal ambient heat stress (spring vs. summer) on physiological and metabolic variables in hair sheep located in an arid region

    Science.gov (United States)

    Macías-Cruz, U.; López-Baca, M. A.; Vicente, R.; Mejía, A.; Álvarez, F. D.; Correa-Calderón, A.; Meza-Herrera, C. A.; Mellado, M.; Guerra-Liera, J. E.; Avendaño-Reyes, L.

    2016-08-01

    Twenty Dorper × Pelibuey primiparous ewes were used to evaluate effects of seasonal ambient heat stress (i.e., spring vs. summer) on physiological and metabolic responses under production conditions in an arid region. Ten ewes experiencing summer heat stress (i.e., temperature = 34.8 ± 4.6 °C; THI = 81.6 ± 3.2 units) and 10 under spring thermoneutral conditions (temperature = 24.2 ± 5.4 °C; THI = 68.0 ± 4.8 units) were corralled together to measure rectal temperature, respiratory frequency, and skin temperatures at 0600, 1200, 1800, and 2400 h on four occasions over 40 days. Blood metabolite and electrolyte concentrations were also measured at 0600 and 1800 hours. Data were analyzed with a completely randomized design using repeated measurements in time. Rectal and skin temperatures, as well as respiratory frequency, were higher ( P < 0.01) in summer than spring at all measured days. Blood serum glucose, cholesterol, triglycerides, and chlorine concentrations were lower ( P < 0.01) in summer than spring at 0800 and 1800 hours. In contrast, summer heat stress increased ( P < 0.01) blood urea and potassium concentrations at 0800 and 1800 hours. Compared with spring thermoneutral conditions, summer heat stress affected the physiological and metabolic status of hair breed ewes in an arid region, which included blood metabolite and electrolyte adjustments to efficiently cope with summer heat stress.

  14. Heat stress increase under climate change twice as large in cities as in rural areas: A study for a densely populated midlatitude maritime region

    Science.gov (United States)

    Wouters, Hendrik; De Ridder, Koen; Poelmans, Lien; Willems, Patrick; Brouwers, Johan; Hosseinzadehtalaei, Parisa; Tabari, Hossein; Vanden Broucke, Sam; van Lipzig, Nicole P. M.; Demuzere, Matthias

    2017-09-01

    Urban areas are usually warmer than their surrounding natural areas, an effect known as the urban heat island effect. As such, they are particularly vulnerable to global warming and associated increases in extreme temperatures. Yet ensemble climate-model projections are generally performed on a scale that is too coarse to represent the evolution of temperatures in cities. Here, for the first time, we combine unprecedented long-term (35 years) urban climate model integrations at the convection-permitting scale (2.8 km resolution) with information from an ensemble of general circulation models to assess temperature-based heat stress for Belgium, a densely populated midlatitude maritime region. We discover that the heat stress increase toward the mid-21st century is twice as large in cities compared to their surrounding rural areas. The exacerbation is driven by the urban heat island itself, its concurrence with heat waves, and urban expansion. Cities experience a heat stress multiplication by a factor 1.4 and 15 depending on the scenario. Remarkably, the future heat stress surpasses everywhere the urban hot spots of today. Our results demonstrate the need to combine information from climate models, acting on different scales, for climate change risk assessment in heterogeneous regions. Moreover, these results highlight the necessity for adaptation to increasing heat stress, especially in urban areas.

  15. How Do I Integrate Hemodynamic Variables When Managing Septic Shock?

    Directory of Open Access Journals (Sweden)

    Olfa Hamzaoui

    2016-11-01

    Full Text Available Hemodynamic management of sepsis-induced circulatory failure is complex since this pathological state includes multiple cardiovascular derangements that can vary from patient to patient according to the degree of hypovolemia, of vascular tone depression, of myocardial depression and of microvascular dysfunction. The treatment of the sepsis-induced circulatory failure is thus not univocal and should be adapted on an individual basis. As physical examination is insufficient to obtain a comprehensive picture of the hemodynamic status, numerous hemodynamic variables more or less invasively collected, have been proposed to well assess the severity of each component of the circulatory failure and to monitor the response to therapy. In this article, we first describe the hemodynamic variables, which are the most relevant to be used, emphasizing on their physiological meaning, their validation and their limitations in patients with septic shock. We then proposed a general approach for managing patients with septic shock by describing the logical steps that need to be followed in order to select and deliver the most appropriate therapies. This therapeutic approach is essentially based on knowledge of physiology, of pathophysiology of sepsis, and of published data from clinical studies that addressed the issue of hemodynamic management of septic shock.

  16. Diagnostic Capacity of Central Hemodynamic Monitoring at Thoracic Cancer Surgery

    Directory of Open Access Journals (Sweden)

    A. M. Batyrshina

    2011-01-01

    Full Text Available Objective: to study hemodynamic changes and the development rate of adaptive reactions in patients with hypokinetic circulation during lung resections varying in volumes. Subjects and methods. Thirty-eight patients with hypo-kinetic circulation, who had undergone sublobar resections, lobectomies, and pneumonectomies, were examined. The values of hemodynamics and gas exchange were recorded at the basic surgical stages and in the early postoperative period (on days 1, 3, 7, and 10. Results. When the patient is placed in the lateral position, the lung is switched off, or the surgical pneumothorax is less than 10—12%, cardiac index changes generally fail to give rise to the decompensation of adaptive processes in the cardiovascular system if the volume of a surgical intervention does not exceed that of sublobar resections or lobectomies. A 15% or more change in cardiac index during controlled lung collapse even with the minimum volume of surgery is indicative of the breakdown of physiological adaptation processes and may manifest itself through the symptoms of cardiorespiratory decompensation in both intra- and postoperative periods. Conclusion. The patients with baseline poor, hypokinetic circulation need not only adequate preoperative estimation of central hemodynamic values, but also continuous intraoperative monitoring of the basic parameters of central hemodynamics. The magnitude of a reduction in cardiac index is prognostically important at the stage of one-lung ventilation during surgical pneumothorax. Key words: hypokinetic circulation, thoracic cancer surgery, central hemodynamic monitoring.

  17. A computational model of hemodynamic parameters in cortical capillary networks.

    Science.gov (United States)

    Safaeian, Navid; Sellier, Mathieu; David, Tim

    2011-02-21

    The analysis of hemodynamic parameters and functional reactivity of cerebral capillaries is still controversial. To assess the hemodynamic parameters in the cortical capillary network, a generic model was created using 2D voronoi tessellation in which each edge represents a capillary segment. This method is capable of creating an appropriate generic model of cerebral capillary network relating to each part of the brain cortex because the geometric model is able to vary the capillary density. The modeling presented here is based on morphometric parameters extracted from physiological data of the human cortex. The pertinent hemodynamic parameters were obtained by numerical simulation based on effective blood viscosity as a function of hematocrit and microvessel diameter, phase separation and plasma skimming effects. The hemodynamic parameters of capillary networks with two different densities (consistent with the variation of the morphometric data in the human cortical capillary network) were analyzed. The results show pertinent hemodynamic parameters for each model. The heterogeneity (coefficient variation) and the mean value of hematocrits, flow rates and velocities of the both network models were specified. The distributions of blood flow throughout the both models seem to confirm the hypothesis in which all capillaries in a cortical network are recruited at rest (normal condition). The results also demonstrate a discrepancy of the network resistance between two models, which are derived from the difference in the number density of capillary segments between the models. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. [Biomechanic shear stress in carotid arteries and atherosclerosis development].

    Science.gov (United States)

    Kaźmierski, Radosław

    2003-01-01

    One of the major hemodynamic forces acting on blood vessels is shear stress, which is, the friction force between the endothelial cell surface and flowing blood. Arterial shear stress within physiologic range (15-70 dyne/cm2) induces endothelial quiescence and an atheroprotective gene expression profile. Low shear stress ( 70 dyne/cm2) induce prothrombotic state.

  19. The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent.

    Science.gov (United States)

    Yu, Yi; Zhou, Yujie; Ma, Qian; Jia, Shuo; Wu, Sijing; Sun, Yan; Liu, Xiaoli; Zhao, Yingxin; Liu, Yuyang; Shi, Dongmei

    2017-01-15

    This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter. However, the effect of the conical stent implantation on the coronary hemodynamics remains unclear. The coronary artery, artery stenosis and two stent models were established by Solidworks software. All models were imported into the computational fluid dynamics (CFD) software ANSYS ICEM-CFD to establish the fluid model. After the boundary conditions were set, CFD analysis was proceeded to compare the effects of two stent implantation on the change of WSS, velocity of flow and FFR. Hemodynamic indexes including FFR, blood flow velocity distribution (BVD) and WSS were improved by either the cylindrical or the conical stent implantation. However, after the conical stent implantation, the change of FFR seemed to be slower and more homogenous; the blood flow velocity was more appropriate without any obvious blood stagnation and direction changes; the WSS after the conical stent implantation was uniform from the proximal to distal side of the stent. Compared with the cylindrical stent, the conical stent implantation in the coronary artery can make the changes of vascular hemodynamic more closer to the physiological condition, which can reduce the incidence of intra-stent restenosis and thrombosis, thus making it more suitable for PCI therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Novel paradigms for dialysis vascular access: upstream hemodynamics and vascular remodeling in dialysis access stenosis.

    Science.gov (United States)

    Remuzzi, Andrea; Ene-Iordache, Bogdan

    2013-12-01

    Failure of hemodialysis access is caused mostly by venous intimal hyperplasia, a fibro-muscular thickening of the vessel wall. The pathogenesis of venous neointimal hyperplasia in primary arteriovenous fistulae consists of processes that have been identified as upstream and downstream events. Upstream events are the initial events producing injury of the endothelial layer (surgical trauma, hemodynamic shear stress, vessel wall injury due to needle punctures, etc.). Downstream events are the responses of the vascular wall at the endothelial injury that consist of a cascade of processes including leukocyte adhesion, migration of smooth muscle cells from the media to the intimal layer, and proliferation. In arteriovenous fistulae, the stenoses occur in specific sites, consistently related to the local hemodynamics determined by the vessel geometry and blood flow pattern. Recent findings that the localization of these sites matches areas of disturbed flow may add new insights into the pathogenesis of neointimal hyperplasia in the venous side of vascular access after the creation of the anastomosis. The detailed study of fluid flow motion acting on the vascular wall in anastomosed vessels and in the arm vasculature at the patient-specific level may help to elucidate the role of hemodynamics in vascular remodeling and neointimal hyperplasia formation. These computational approaches may also help in surgical planning for the amelioration of clinical outcome. This review aims to discuss the role of the disturbed flow condition in acting as upstream event in the pathogenesis of venous intimal hyperplasia and in producing subsequent local vascular remodeling in autogenous arteriovenous fistulae used for hemodialysis access. The potential use of blood flow analysis in the management of vascular access is also discussed.

  1. Effect of Benson Relaxation Techniques on Hemodynamic Variables of Patient Undergoing Coronary Angiography

    Directory of Open Access Journals (Sweden)

    M khani

    2005-01-01

    Full Text Available Introduction: Invasive diagnostic procedures such as coronary angiography, in most cases, are accompanied by stress and anxiety for patients,which may effect on hemodynamic signs. Materials and Methods:This research, as a quasi experimental study, has the objective to determine the influence of applying methods of relaxation on hemodynamic signs in hospitalized 40 patients, experienciny coronary angiography (CA,, has been studied, in regard to existing conditions and methods of sampling and random allocation to two groups of control and relaxation at 2003 . Data collection tool included demographic and disease related information sheet, as well as record sheets for hemodynamic parameters at intervals of 8-12 and ½ hrs before, during and after the angiography. For relaxation group, the researcher would speak individually about the influence of relaxation, the day before angiography; Then with the aid of client himself/herself, performed relaxation instances in a single bout, and eventually asked client to perform relaxation technique 2-3 times before going for angiography. In control group was attended in the usual manner preangiographically. Homodynamic parameters were measured in both groups 8-12 and ½ hrs, before during and after CA. Afterward, resulted data were analyzed statistically by T-Test Chi-squre. Results: With T-Test, respiratory rates½ hrs, beforeAngiography, diastolic blood pressure and Respiratory Rate after Angiography showed statisticaly significant difference between two groups (P0.05.but most of parameters showed clinically significant difference between two groups. Conclusion: Therfore it is offered that relaxation method is applied after invasive procedures.

  2. The physiological stress response and oxidative stress biomarkers in rainbow trout and brook trout from selenium-impacted streams in a coal mining region

    Energy Technology Data Exchange (ETDEWEB)

    Miller, L.L.; Rasmussen, J.B.; Palace, V.P.; Hontela, A. [University of Lethbridge, Lethbridge, AB (Canada). Dept. of Biological Science

    2009-11-15

    Selenium (Se) is an essential element that can be toxic at concentrations slightly greater than those required for homeostasis. The main chronic toxic effects of Se in fish are teratogenic deformities, but Se can also activate the physiological stress response and redox cycle with reduced glutathione causing oxidative damage. Rainbow trout, Oncorhynchus mykiss, appear to be more sensitive to Se than brook trout, Salvelinus fontinalis. The objective of this study was to compare the physiological stress response (plasma cortisol, glucose, triiodothyronine, thyroxine, gill Na+/K+ ATPase, cortisol secretory capacity, K and liver somatic index) and oxidative stress biomarkers (liver GSH, GPx, lipid peroxidation, vitamin A and vitamin E) in rainbow trout (RNTR) and brook trout (BKTR) collected from reference and Se-exposed streams. The physiological stress response was not impaired (cortisol secretory capacity unchanged); although there were species differences in plasma cortisol and plasma glucose levels. Liver GSH, GPx and vitamin levels were higher in RNTR than BKTR, but lipid peroxidation levels were not different. The elevated GSH reserves may make RNTR more sensitive to Se-induced lipid peroxidation, but this may be offset by the RNTR's higher antioxidant (GPx and vitamin) levels. Species-specific biochemical differences may mediate differences in Se sensitivity and be used in aquatic Se risk assessments.

  3. Invasive and noninvasive hemodynamic monitoring of patients with cerebrovascular accidents.

    Science.gov (United States)

    Velmahos, G C; Wo, C C; Demetriades, D; Bishop, M H; Shoemaker, W C

    1998-01-01

    Seventeen patients with hemodynamic instability from acute cerebrovascular accidents were evaluated shortly after arrival at the emergency department of a university-run county hospital with both invasive Swan-Ganz pulmonary artery catheter placement and a new, noninvasive, thoracic electrical bioimpedance device. Values were recorded and temporal patterns of survivors and nonsurvivors were described. Cardiac indices obtained simultaneously by the 2 techniques were compared. Of the 17 patients, 11 (65%) died. Survivors had higher values than nonsurvivors for mean arterial pressure, cardiac index, and oxygen saturation, delivery, and consumption at comparable times. Cardiac index values, as measured by invasive and noninvasive methods, were correlated. We concluded that hemodynamic monitoring in an acute care setting may recognize temporal circulatory patterns associated with outcome. Noninvasive electrical bioimpedance technology offers a new method for early hemodynamic evaluation. Further research in this area is warranted. PMID:9682626

  4. [Hemodynamic monitoring - imaging procedures / cardiac ultrasound].

    Science.gov (United States)

    Batz, Gerhard; Dinkel, Michael

    2016-10-01

    Echocardiography as an imaging method in anaesthesia and intensive care medicine has enabled a new dimension of hemodynamic monitoring: the direct visualization of the cardiac function and its disruptions. Preconditions for a broad application in this area was the development of mobile, high-definition ultrasonic devices and the origination of focused examination techniques. A successful application of this method requires the respective know-how of the examiner, in order to take relevant decisions and avoid misdiagnoses. The following article shows the advantages and limitations of echocardiography in the diagnosis of hemodynamic instability. For TTE and TEE focused examination techniques are illustrated and evaluated with regards to their applicability to hemodynamic monitoring. Furthermore, the requirements on devices and education of the examiner are discussed. © Georg Thieme Verlag Stuttgart · New York.

  5. Ocular hemodynamics and glaucoma: the role of mathematical modeling.

    Science.gov (United States)

    Harris, Alon; Guidoboni, Giovanna; Arciero, Julia C; Amireskandari, Annahita; Tobe, Leslie A; Siesky, Brent A

    2013-01-01

    To discuss the role of mathematical modeling in studying ocular hemodynamics, with a focus on glaucoma. We reviewed recent literature on glaucoma, ocular blood flow, autoregulation, the optic nerve head, and the use of mathematical modeling in ocular circulation. Many studies suggest that alterations in ocular hemodynamics play a significant role in the development, progression, and incidence of glaucoma. Although there is currently a limited number of studies involving mathematical modeling of ocular blood flow, regulation, and diseases (such as glaucoma), preliminary modeling work shows the potential of mathematical models to elucidate the mechanisms that contribute most significantly to glaucoma progression. Mathematical modeling is a useful tool when used synergistically with clinical and laboratory data in the study of ocular blood flow and glaucoma. The development of models to investigate the relationship between ocular hemodynamic alterations and glaucoma progression will provide a unique and useful method for studying the pathophysiology of glaucoma.

  6. Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.

    Science.gov (United States)

    Araújo, Marcelo Marotta; Lauria, Andrezza; Mendes, Marcelo Breno Meneses; Claro, Ana Paula Rosifini Alves; Claro, Cristiane Aparecida de Assis; Moreira, Roger William Fernandes

    2015-12-01

    The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.

  7. Sex- and brain region-specific acceleration of β-amyloidogenesis following behavioral stress in a mouse model of Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Devi Latha

    2010-11-01

    Full Text Available Abstract Background It is hypothesized that complex interactions between multiple environmental factors and genetic factors are implicated in sporadic Alzheimer's disease (AD; however, the underlying mechanisms are poorly understood. Importantly, recent evidence reveals that expression and activity levels of the β-site APP cleaving enzyme 1 (BACE1, which initiates amyloid-β (Aβ production, are elevated in AD brains. In this study, we investigated a molecular mechanism by which sex and stress interactions may accelerate β-amyloidogenesis and contribute to sporadic AD. Results We applied 5-day restraint stress (6 h/day to the male and female 5XFAD transgenic mouse model of AD at the pre-pathological stage of disease, which showed little amyloid deposition under non-stressed control conditions. Exposure to the relatively brief behavioral stress increased levels of neurotoxic Aβ42 peptides, the β-secretase-cleaved C-terminal fragment (C99 and plaque burden in the hippocampus of female 5XFAD mice but not in that of male 5XFAD mice. In contrast, significant changes in the parameters of β-amyloidosis were not observed in the cerebral cortex of stressed male or female 5XFAD mice. We found that this sex- and brain region-specific acceleration of β-amyloidosis was accounted for by elevations in BACE1 and APP levels in response to adverse stress. Furthermore, not only BACE1 mRNA but also phosphorylation of the translation initiation factor eIF2α (a proposed mediator of the post-transcriptional upregulation of BACE1 was elevated in the hippocampus of stressed female 5XFAD mice. Conclusions Our results suggest that the higher prevalence of sporadic AD in women may be attributable to the vulnerability of female brains (especially, the hippocampus to stressful events, which alter APP processing to favor the β-amyloidogenesis through the transcriptional and translational upregulation of BACE1 combined with elevations in its substrate APP.

  8. Hemodynamic monitoring in the era of digital health.

    Science.gov (United States)

    Michard, Frederic

    2016-12-01

    Digital innovations are changing medicine, and hemodynamic monitoring will not be an exception. Five to ten years from now, we can envision a world where clinicians will learn hemodynamics with simulators and serious games, will monitor patients with wearable or implantable sensors in the hospital and after discharge, will use medical devices able to communicate and integrate the historical, clinical, physiologic and biological information necessary to predict adverse events, propose the most rationale therapy and ensure it is delivered properly. Considerable intellectual and financial investments are currently made to ensure some of these new ideas and products soon become a reality.

  9. Rifaximin has no effect on hemodynamics in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Kimer, Nina; Pedersen, Julie Steen; Busk, Troels Malte

    2017-01-01

    Decompensated cirrhosis is characterized by disturbed systemic and splanchnic hemodynamics. Bacterial translocation from the gut is considered the key driver in this process. Intestinal decontamination with rifaximin may improve hemodynamics. This double-blind, randomized, controlled trial...... years (±8.4), average Child score 8.3 (±1.3), and Model for End-Stage Liver Disease score 11.7 (±3.9). Measurements of hepatic venous pressure gradient, cardiac output, and systemic vascular resistance were made at baseline and after 4 weeks. The glomerular filtration rate and plasma renin...

  10. Appearance of amyloid beta-like substances and delayed-type apoptosis in rat hippocampus CA1 region through aging and oxidative stress.

    Science.gov (United States)

    Fukui, Koji; Takatsu, Hirokatsu; Shinkai, Tadashi; Suzuki, Shozo; Abe, Kouichi; Urano, Shiro

    2005-12-01

    To elucidate whether oxidative stress induces cognitive deficit, and whether nerve cells in the hippocampus, which modulates learning and memory functions in the brain, are damaged by oxidative stress and during aging, the influence of hyperoxia as oxidative stress on either the cognitive function of rats or the oxidative damage of nerve cells was investigated. Young rats showed better learning ability than both old rats and vitamin E-deficient young rats. Vitamin E- supplemented young rats showed similar ability to young control rats. After they learned the location of the platform in the Morris water maze test, the young rats and vitamin E-supplemented young rats were subjected to oxidative stress for 48 h, and the old rats and vitamin E-deficient young rats were kept in normal atmosphere. The memory function of the old rats and vitamin E-deficient young rats declined even when they were not subjected to oxidative stress for 48 h. In contrast, the young rats maintained their memory function for 4 days after the oxidative stress. However, their learning abilities suddenly declined toward that of the normal old rats after 5 days. At this point, nerve cell loss and apoptosis were observed in the hippocampal CA 1 region of young rats. Vitamin E-supplementation in the young rats prevented either memory deficit or the induction of delayed-type apoptosis. The old rats and vitamin E-deficient young rats kept in normal atmosphere for 48 h also showed apoptosis in the hippocampus. Also, 10 days after oxidative stress, amyloid beta-like substances appeared in the CA-1 region of control young rats; these substances were also observed in the CA-1 region of the old rats and vitamin E- deficient young rats. These results suggest that reactive oxygen species (ROS) generated by oxidative stress induced amyloid beta-like substances and delayed-type apoptosis in the rat hippocampus, resulting in cognitive deficit. Since amyloid beta in Alzheimer's disease characterized by cognitive

  11. Chronic Stress and Peripheral Pain: Evidence for Distinct, Region-specific Changes in Visceral and Somatosensory Pain Regulatory Pathways

    Science.gov (United States)

    Zheng, Gen; Hong, Shuangsong; Hayes, John M; Wiley, John W

    2015-01-01

    Chronic stress alters the hypothalamic-pituitary-adrenal (HPA) axis and enhances visceral and somatosensory pain perception. It is unresolved whether chronic stress has distinct effects on visceral and somatosensory pain regulatory pathways. Previous studies reported that stress-induced visceral hyperalgesia is associated with reciprocal alterations of endovanilloid and endocannabinoid pain pathways in DRG neurons innervating the pelvic viscera. In this study, we compared somatosensory and visceral hyperalgesia with respect to differential responses of peripheral pain regulatory pathways in a rat model of chronic, intermittent stress. We found that chronic stress induced reciprocal changes in the endocannabinoid 2-AG (increased) and endocannabinoid degradation enzymes COX-2 and FAAH (decreased), associated with down-regulation of CB1 and up-regulation of TRPV1 receptors in L6-S2 DRG but not L4-L5 DRG neurons. In contrast, sodium channels Nav1.7 and Nav1.8 were up-regulated in L4-L5 but not L6-S2 DRGs in stressed rats, which was reproduced in control L4-L5 DRGs treated with corticosterone in vitro. The reciprocal changes of CB1, TRPV1 and sodium channels were cell-specific and observed in the sub-population of nociceptive neurons. Behavioral assessment showed that visceral hyperalgesia persisted, whereas somatosensory hyperalgesia and enhanced expression of Nav1.7 and Nav1.8 sodium channels in L4-L5 DRGs normalized 3 days after completion of the stress phase. These data indicate that chronic stress induces visceral and somatosensory hyperalgesia that involves differential changes in endovanilloid and endocannabinoid pathways, and sodium channels in DRGs innervating the pelvic viscera and lower extremities. These results suggest that chronic stress-induced visceral and lower extremity somatosensory hyperalgesia can be treated selectively at different levels of the spinal cord. PMID:26408049

  12. Moyamoya syndrome: impaired hemodynamics on ECD SPECT after EEG controlled hyperventilation

    Energy Technology Data Exchange (ETDEWEB)

    Matheja, P.; Weckesser, M.; Franzius, C.; Loettgen, J.; Schober, O. [Muenster Univ. (Germany). Dept. of Nuclear Medicine; Debus, O.; Kurlemann, G. [Dept. of Neuropediatrics, Muenster Univ. (Germany)

    2002-02-01

    Background and purpose: Ischemic symptoms in children with Moyamoya syndrome are typically provoked by hyperventilation (HV) and are accompanied by the ''re-build-up'' phenomenon in EEG. The value of scintigraphic detection of HV-provoked perfusion deficits remains to be elucidated. Patients and methods: In seven children with Moyamoya syndrome regional cerebral blood flow was assessed by {sup 99m}Tc-ethyl-cysteine-dimer (ECD) single photon emission computed tomography (SPECT) after HV and under baseline conditions to identify ischemia prone regions. Results: Regional marked hypoperfusion after HV was found in all patients. Predominant perfusion deficits were detected in the frontal lobes. Conclusion: ECD SPECT is a potential tool for the preoperative evaluation of cerebral hemodynamics and for monitoring angiosurgical therapies in Moyamoya disease. (orig.)

  13. Metabolic and hemodynamic evaluation of brain metastases from small cell lung cancer with positron emission tomography

    DEFF Research Database (Denmark)

    Lassen, U; Andersen, P; Daugaard, G

    1998-01-01

    Brain metastases from small cell lung cancer respond to chemotherapy, but response duration is short and the intracerebral concentration of chemotherapy may be too low because of the characteristics of the blood-brain barrier. Positron emission tomography has been applied in a variety of tumors...... for studies of metabolic and hemodynamic features. This study was performed to determine regional cerebral metabolic rate of glucose (rCMRglu), regional cerebral blood flow (rCBF), and regional cerebral blood volume (rCBV) in brain metastases from small cell lung cancer and the surrounding brain. Tumor r......CMRglu, rCBF, and rCBV exerted a broad variability, but were higher than the corresponding values in white matter and higher than or similar to those of gray matter. Tumor rCMRglu and rCBF were highly correlated (P

  14. Fluid-Structure Interaction Modeling of Intracranial Aneurysm Hemodynamics: Effects of Different Assumptions

    Science.gov (United States)

    Rajabzadeh Oghaz, Hamidreza; Damiano, Robert; Meng, Hui

    2015-11-01

    Intracranial aneurysms (IAs) are pathological outpouchings of cerebral vessels, the progression of which are mediated by complex interactions between the blood flow and vasculature. Image-based computational fluid dynamics (CFD) has been used for decades to investigate IA hemodynamics. However, the commonly adopted simplifying assumptions in CFD (e.g. rigid wall) compromise the simulation accuracy and mask the complex physics involved in IA progression and eventual rupture. Several groups have considered the wall compliance by using fluid-structure interaction (FSI) modeling. However, FSI simulation is highly sensitive to numerical assumptions (e.g. linear-elastic wall material, Newtonian fluid, initial vessel configuration, and constant pressure outlet), the effects of which are poorly understood. In this study, a comprehensive investigation of the sensitivity of FSI simulations in patient-specific IAs is investigated using a multi-stage approach with a varying level of complexity. We start with simulations incorporating several common simplifications: rigid wall, Newtonian fluid, and constant pressure at the outlets, and then we stepwise remove these simplifications until the most comprehensive FSI simulations. Hemodynamic parameters such as wall shear stress and oscillatory shear index are assessed and compared at each stage to better understand the sensitivity of in FSI simulations for IA to model assumptions. Supported by the National Institutes of Health (1R01 NS 091075-01).

  15. Use of Diazepam to Correct Hemodynamic Changes in Explosive Mine Injury: Experimental Study

    Directory of Open Access Journals (Sweden)

    V. N. Yelsky

    2007-01-01

    Full Text Available Objective. To study the hemodynamic effect of benzodiazepine tranquilizers in explosive mine injury in an experiment.Materials and methods. The study was performed on non-inbred male rats; hemodynamic parameters were examined at the systemic, organ, and microcirculatory levels.Results. Circulatory adaptive changes occurring at the beginning of a premorbid load further become pathogenic, which in combination with a progressive change in blood-brain barrier resistance results in the severer course of premorbid load-complicated explosive mine injury than that of isolated one. Correction of occurring disorders, by stimulating the stress-limiting GABAergic system with diazepam, is most effective within the first 25 minutes after isolated explosive mine injury and within the first 15 minutes after complicated one. Conclusion. Under the conditions of deep collieries where medical aid was generally late, emergency medical activation of urgent adaptation mechanisms by the techniques specially developed by the authors for these conditions is the most effective way of preventing the complications of explosive mine injury. 

  16. Systemic Hemodynamic Atherothrombotic Syndrome and Resonance Hypothesis of Blood Pressure Variability: Triggering Cardiovascular Events

    Science.gov (United States)

    2016-01-01

    Blood pressure (BP) exhibits different variabilities and surges with different time phases, from the shortest beat-by-beat to longest yearly changes. We hypothesized that the synergistic resonance of these BP variabilites generates an extraordinarily large dynamic surge in BP and triggers cardiovascular events (the resonance hypothesis). The power of pulses is transmitted to the peripheral sites without attenuation by the large arteries, in individuals with stiffened arteries. Thus, the effect of a BP surge on cardiovascular risk would be especially exaggerated in high-risk patients with vascular disease. Based on this concept, our group recently proposed a new theory of systemic hemodynamic atherothromboltic syndrome (SHATS), a vicious cycle of hemodynamic stress and vascular disease that advances organ damage and triggers cardiovascular disease. Clinical phenotypes of SHATS are large-artery atherothombotic diseases such as stroke, coronary artery disease, and aortic and pheripheral artery disease; small-artery diseases, and microcirculation-related disease such as vascular cognitive dysfunction, heart failure, and chronic kidney disease. The careful consideration of BP variability and vascular diseases such as SHATS, and the early detection and management of SHATS, will achieve more effective individualized cardiovascular protection. In the near future, information and communication technology-based 'anticipation medicine' predicted by the changes of individual BP values could be a promising approach to achieving zero cardiovascular events. PMID:27482253

  17. Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta.

    Science.gov (United States)

    Okamoto, Eiji; Yano, Tetsuya; Miura, Hidekazu; Shiraishi, Yasuyuki; Yambe, Tomoyuki; Mitamura, Yoshinori

    2017-12-01

    We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.

  18. Does lower limb exercise worsen renal artery hemodynamics in patients with abdominal aortic aneurysm?

    Directory of Open Access Journals (Sweden)

    Anqiang Sun

    Full Text Available Renal artery stenosis (RAS and renal complications emerge in some patients after endovascular aneurysm repair (EVAR to treat abdominal aorta aneurysm (AAA. The mechanisms for the causes of these problems are not clear. We hypothesized that for EVAR patients, lower limb exercise could negatively influence the physiology of the renal artery and the renal function, by decreasing the blood flow velocity and changing the hemodynamics in the renal arteries. To evaluate this hypothesis, pre- and post-operative models of the abdominal aorta were reconstructed based on CT images. The hemodynamic environment was numerically simulated under rest and lower limb exercise conditions. The results revealed that in the renal arteries, lower limb exercise decreased the wall shear stress (WSS, increased the oscillatory shear index (OSI and increased the relative residence time (RRT. EVAR further enhanced these effects. Because these parameters are related to artery stenosis and atherosclerosis, this preliminary study concluded that lower limb exercise may increase the potential risk of inducing renal artery stenosis and renal complications for AAA patients. This finding could help elucidate the mechanism of renal artery stenosis and renal complications after EVAR and warn us to reconsider the management and nursing care of AAA patients.

  19. An investigation of patterns in hemodynamic data indicative of impending hypotension in intensive care

    Directory of Open Access Journals (Sweden)

    Lee Joon

    2010-10-01

    Full Text Available Abstract Background In the intensive care unit (ICU, clinical staff must stay vigilant to promptly detect and treat hypotensive episodes (HEs. Given the stressful context of busy ICUs, an automated hypotensive risk stratifier can help ICU clinicians focus care and resources by prospectively identifying patients at increased risk of impending HEs. The objective of this study was to investigate the possible existence of discriminatory patterns in hemodynamic data that can be indicative of future hypotensive risk. Methods Given the complexity and heterogeneity of ICU data, a machine learning approach was used in this study. Time series of minute-by-minute measures of mean arterial blood pressure, heart rate, pulse pressure, and relative cardiac output from 1,311 records from the MIMIC II Database were used. An HE was defined as a 30-minute period during which the mean arterial pressure was below 60 mmHg for at least 90% of the time. Features extracted from the hemodynamic data during an observation period of either 30 or 60 minutes were analyzed to predict the occurrence of HEs 1 or 2 hours into the future. Artificial neural networks (ANNs were trained for binary classification (normotensive vs. hypotensive and regression (estimation of future mean blood pressure. Results The ANNs were successfully trained to discriminate patterns in the multidimensional hemodynamic data that were predictive of future HEs. The best overall binary classification performance resulted in a mean area under ROC curve of 0.918, a sensitivity of 0.826, and a specificity of 0.859. Predicting further into the future resulted in poorer performance, whereas observation duration minimally affected performance. The low prevalence of HEs led to poor positive predictive values. In regression, the best mean absolute error was 9.67%. Conclusions The promising pattern recognition performance demonstrates the existence of discriminatory patterns in hemodynamic data that can indicate

  20. Magnetic resonance imaging based noninvasive measurements of brain hemodynamics in neonates

    DEFF Research Database (Denmark)

    De Vis, Jill B; Alderliesten, Thomas; Hendrikse, Jeroen

    2016-01-01

    Perinatal disturbances of brain hemodynamics can have a detrimental effect on the brain's parenchyma with consequently adverse neurodevelopmental outcome. Noninvasive, reliable tools to evaluate the neonate's brain hemodynamics are scarce. Advances in magnetic resonance imaging have provided new...

  1. Methylene Blue Is Effective to Reverse Refractory Hemodynamic Instability due to Dimethoate Poisoning

    Directory of Open Access Journals (Sweden)

    Nick Youssefi

    2015-09-01

    Conclusion:MB treatment was effective to reverse hypotension and restore hemodynamic instability caused by dimethoate poisoning. This index case may pave way to further investigation of MB therapy for OP-induced hemodynamic instabilities.

  2. [A follow-up study on the post-traumatic stress disorders among middle school students in Wenchuan earthquake region].

    Science.gov (United States)

    Yang, Yan-Fang; Liu, Xiao-Xia; Zeng, Zi-Qian; Xiang, Ying-Jun; Liu, Zhi-Yue; Hu, Xiao-Qin; Li, Juan; Li, Ting; Hou, Feng-Su; Yuan, Ping

    2011-04-01

    This study was to identify the post-traumatic stress disorder (PTSD) changes and the relative risk factors within one year after Wenchuan earthquake among middle school students in the disaster area. A total of 1966 students from 3 schools in Wenchuan earthquake region were selected as the target population. For each student, personal basic information and standard psychological scale (PCL-C, PSSS) were investigated by a self-administrated questionnaire in the 3rd, the 6th, the 9th and the 12th month after the earthquake, respectively. PTSD trends over the time and the associated risk factors were analyzed through the establishment of multi-level random coefficient model. There were 1677 middle school students fully participated in the PTSD follow-up study by turning in the valid questionnaires. The averaged scores of PTSD at the time of the 3rd, the 6th, the 9th and the 12th month after the earthquake were 35.14 ± 11.08, 32.90 ± 11.03, 30.67 ± 11.28 and 29.75 ± 11.22, respectively. Meanwhile, the general incidences of PTSD were 36.6% (613/1677), 30.7% (515/1677), 24.8% (416/1677)and 22.2% (373/1677), respectively. The median score of perceived social support system was 60.00 and the general incidences of PSS was 17.20% (289/1677). The PTSD scores for the students had a decreasing trend during the period of our observation (β(time) = -1.879, χ(2) = 47.03, P students were 35.46, 33.28, 30.18, 29.22; for senior school students were 34.89, 32.62, 31.04, 30.15. Moreover, two factors, gender and grade, were related with the decreasing trend (the trend for girls and senior school students was sharper than that for boys and junior school students) (β(gender-time) = -0.354, χ(2) = 4.83, P students recovered more slowly.

  3. The Influence of Age on Hemodynamic Parameters During Rest and Exercise in Healthy Individuals

    DEFF Research Database (Denmark)

    Wolsk, Emil; Bakkestrøm, Rine; Thomsen, Jacob H

    2017-01-01

    OBJECTIVES: The authors sought to obtain hemodynamic estimates across a wide age span and in both sexes for future reference and compare these estimates with current guideline diagnostic hemodynamic thresholds for abnormal filling pressure and pulmonary hypertension. BACKGROUND: At present....... Participants had hemodynamic parameters measured using right heart catheterization during rest, passive leg raise, and incremental exercise. RESULTS: During rest, all hemodynamic parameters were similar between age groups, apart from blood pressure. During leg raise and incremental exercise...

  4. The effects of unilateral and bilateral spinal anaesthesia on hemodynamic parameters in patients surgically treated for inguinal hernia: Hemodynamic parameters and spinal anesthesia

    Directory of Open Access Journals (Sweden)

    Milosavljević Snežana

    2016-01-01

    Full Text Available Introduction: Conventional bilateral spinal anaesthesia is commonly used for surgical treatment of inguinal hernia because it causes fast development of block with relatively small dosage of local anaesthetic; furthermore, it is easily administered, reduces the level of metabolic response to stress, reduces the incidence of deep venous thrombosis and respiratory depression. On the other hand, the main side effect is hypotension Objective: The goal of the research was to determine which of the two methods of spinal anaesthesia (conventional bilateral, achieved with regular dosage of long-lasting bupivacaine or hypobaric unilateral, achieved with combined application of bupivacaine and fentanyl ensures higher hemodynamic stability during tension-free hernioplasty in patients from group I and II of ASA classification system. Methods: The research was conducted as a prospective, controlled clinical study with the total amount of 50 patients, males and females, and within the age span ranging from 17 to 77, who all had indications for surgical treatment of one-sided inguinal hernia under spinal anaesthesia. The hemodynamic parameters (heart rate, systolic, diastolic and mean arterial pressure were measured during following intervals: T1 - during preanaesthetic visit, T2 - after premedication and the iv administration of Ringer's lactate solution, T3 - 15 minutes after the administration of spinal anaesthesia, T4 - after the surgical incision, T5 - intraoperatively, T6 - during the placement of the last surgical stitch on the skin, T7 - one hour postoperatively. Results: The results showed that the frequency of clinically relevant hypotension was statistically much higher in patients with bilateral spinal anaesthesia (24 % when compared to patients administered with unilateral spinal anaesthesia (4%. Ten minutes after the application of spinal anaesthesia the mean arterial pressure has decreased by 20% when compared to basic values in group BB, and by

  5. Prospective evaluation of intraoperative hemodynamics in liver transplantation with whole, partial and DCD grafts

    NARCIS (Netherlands)

    Sainz-Barriga, M; Reyntjens, K; Costa, M G; Scudeller, L; Rogiers, X; Wouters, P; de Hemptinne, B; Troisi, R I

    The interaction of systemic hemodynamics with hepatic flows at the time of liver transplantation (LT) has not been studied in a prospective uniform way for different types of grafts. We prospectively evaluated intraoperative hemodynamics of 103 whole and partial LT. Liver graft hemodynamics were

  6. Acute hemodynamic response to vasodilators in primary pulmonary hypertension.

    Directory of Open Access Journals (Sweden)

    Kulkarni H

    1996-01-01

    Full Text Available Acute hemodynamic effects of high flow oxygen (O2 inhalation, sublingual isosorbide dinitrate (ISDN, intravenous aminophylline (AMN and sublingual nifedipine (NIF were studied in 32 patients with primary pulmonary hypertension (PPH. In 30 out of 32 patients the basal ratio of pulmonary to systemic vascular resistance (Rp/Rs was > 0.5 (mean = 0.77 +/- 0.20. Oxygen caused significant decrease in the mean resistance ratio to 0.68 +/- 0.20 (p = 0.005. ISDN, AMN and NIF caused increase in the resistance ratio to 0.79 +/- 0.26; 0.78 +/- 0.26; and 0.80 +/- 0.23 respectively. O2, ISDN, AMN and NIF caused a fall of Rp/Rs in 21 (65.6%, 10 (31.2%, 10(31.2% and 9(28.1% patients respectively. Thus, of the four drugs tested high flow O2 inhalation resulted in fall of Rp/Rs in two thirds of patients whereas ISDN, AMN and NIF caused a mean rise in Rp/Rs. One third of patients did respond acutely to the latter three drugs. Acute hemodynamic studies are useful before prescribing vasodilators in patients with PPH since more of the commonly used drugs like ISDN, AMN, NIF could have detrimental hemodynamic responses in some patients. However, great caution should be exercised before performing hemodynamic study as the procedure has definite mortality and morbidity.

  7. The hemodynamic basis of exercise intolerance in tricuspid regurgitation

    DEFF Research Database (Denmark)

    Andersen, Mads Jønsson; Nishimura, Rick a; Borlaug, Barry A

    2014-01-01

    BACKGROUND:Patients with severe tricuspid regurgitation (TR) frequently present with exertional fatigue and dyspnea, but the hemodynamic basis for exercise limitation in people with TR remains unclear. METHODS AND RESULTS:Twelve subjects with normal left ventricular (LV) ejection fraction and gra...

  8. Hemodynamic causes of exercise intolerance in Fontan patients

    DEFF Research Database (Denmark)

    Hebert, Anders; Jensen, Annette S; Mikkelsen, Ulla Ramer

    2014-01-01

    BACKGROUND: Exercise intolerance is frequent among Fontan patients and an important determinant for quality of life. This study investigated the hemodynamic causes of impaired exercise capacity in Fontan patients with particular focus on the influence of stroke volume index (SVI) and heart rate (HR...

  9. Initial approach to hypertension in the hemodynamics unit: review article

    Directory of Open Access Journals (Sweden)

    Gustavo Teixeira Fulton Schimit

    2013-06-01

    Full Text Available Correct identification and early management of hypertensive disorders should be a part of the therapeutic repertoire of every professional working in hemodynamics units. Based on recent publications, this study aims to propose a practical approach to the identification and early management of these disorders in this type of service.

  10. Hemodynamic Changes during Epidural Anesthesia with Various Local Anesthetics

    Directory of Open Access Journals (Sweden)

    Ye. M. Shifman

    2008-01-01

    Full Text Available Central hemodynamic stability during gynecological laparoscopic operations remains an important problem of anes-thesiological monitoring. Subjects and methods. Fifty-eight patients who had undergone various gynecological laparoscopic operations were examined. According to the mode of anesthesia, the patients were divided into 2 groups: 1 29 patients who received epidural anesthesia with ropivacaine; 2 29 who had epidural anesthesia using lidocaine. The indices of cardiac performance (stroke volume, stroke index, and cardiac output, blood (diastolic, systolic, and mean pressure, vascular parameters (linear blood flow velocity, total peripheral vascular resistance were determined by volumetric compression oscillometry. Results. The study indicated that all the modes of anesthesia demonstrated the satisfactory condition of the cardiovascular system, but the highest stability of hemodynamic parameters was recorded in the epidural ropivacaine group. In this group, there were steady-state reductions in diastolic, systolic, mean blood pressures, and total vascular peripheral resistance and increases in stroke index, stroke volume, and linear blood flow velocity. Conclusion. Epidural anesthesia using ropivacaine during gynecological surgical endoscopic interventions is the method of analgesia causing minimal hemodynamic disorders. Key words: hemodynamics, epidural anesthesia, laparoscopic gynecological operations.

  11. Hemodynamics and vasopressor support in therapeutic hypothermia after cardiac arrest

    DEFF Research Database (Denmark)

    Bro-Jeppesen, John; Kjaergaard, Jesper; Søholm, Helle

    2014-01-01

    AIM: Inducing therapeutic hypothermia (TH) in Out-of-Hospital Cardiac Arrest (OHCA) can be challenging due to its impact on central hemodynamics and vasopressors are frequently used to maintain adequate organ perfusion. The aim of this study was to assess the association between level...

  12. Dietary melatonin alters uterine artery hemodynamics in pregnant holstein heifers

    Science.gov (United States)

    The objective was to examine uterine artery hemodynamics and maternal serum profiles in pregnant heifers supplemented with dietary melatonin (MEL) or no supplementation (CON). In addition, melatonin receptor–mediated responses in steroid metabolism were examined using a bovine endometrial epithelial...

  13. Relationship Between Serum Uric Acid Levels and Intrarenal Hemodynamic Parameters

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    Hideki Uedono

    2015-06-01

    Full Text Available Background/Aims: Hyperuricemia has been reported to affect renal hemodynamics in rat models. We evaluate the relationship between serum uric acid and intrarenal hemodynamic parameters in humans, utilizing the plasma clearance of para-aminohippurate (CPAH and inulin (Cin. Methods: Renal and glomerular hemodynamics were assessed by simultaneous measurement of CPAH and Cin in 58 subjects. Of these, 19 subjects were planned to provide a kidney for transplantation; 26 had diabetes without proteinuria; and 13 had mild proteinuria. Renal and glomerular hemodynamics were calculated using Gomez`s formulae. Results: Cin was more than 60 ml/min/1.73m2 in all subjects. Serum uric acid levels correlated significantly with vascular resistance at the afferent arteriole (Ra (r = 0.354, p = 0.006 but not with that of the efferent arteriole (Re. Serum uric acid levels (β = 0.581, p = a after adjustment for several confounders (R2 = 0.518, p = Conclusions: These findings suggest, for the first time in humans, that higher serum uric acid levels are associated significantly with Ra in subjects with Cin > 60 ml/min/1.73m2. The increase in Ra in subjects with higher uric acid levels may be related to dysfunction of glomerular perfusion.

  14. Altering hemodynamics leads to congenital heart defects (Conference Presentation)

    Science.gov (United States)

    Ford, Stephanie M.; McPheeters, Matthew T.; Wang, Yves T.; Gu, Shi; Doughman, Yong Qiu; Strainic, James P.; Rollins, Andrew M.; Watanabe, Michiko; Jenkins, Michael W.

    2016-03-01

    The role of hemodynamics in early heart development is poorly understood. In order to successfully assess the impact of hemodynamics on development, we need to monitor and perturb blood flow, and quantify the resultant effects on morphology. Here, we have utilized cardiac optical pacing to create regurgitant flow in embryonic hearts and OCT to quantify regurgitation percentage and resultant morphology. Embryonic quail in a shell-less culture were optically paced at 3 Hz (well above the intrinsic rate or 1.33-1.67 Hz) on day 2 of development (3-4 weeks human) for 5 minutes. The pacing fatigued the heart and led to a prolonged period (> 1 hour) of increased regurgitant flow. Embryos were kept alive until day 3 (cardiac looping - 4-5 weeks human) or day 8 (4 chambered heart - 8 weeks human) to quantify resultant morphologic changes with OCT. All paced embryos imaged at day 3 displayed cardiac defects. The extent of regurgitant flow immediately after pacing was correlated with cardiac cushion size 24-hours post pacing (p-value cardio-facial/DiGeorge syndrome models suggesting that hemodynamics plays a role in these syndromes as well. Utilizing OCT and optical pacing to understand hemodynamics in development is an important step towards determining CHD mechanisms and ultimately developing earlier treatments.

  15. Less invasive hemodynamic monitoring in critically ill patients

    NARCIS (Netherlands)

    Teboul, Jean-Louis; Saugel, Bernd; Cecconi, Maurizio; De Backer, Daniel; Hofer, Christoph K.; Monnet, Xavier; Perel, Azriel; Pinsky, Michael R.; Reuter, Daniel A.; Rhodes, Andrew; Squara, Pierre; Vincent, Jean-Louis; Scheeren, Thomas W.

    Over the last decade, the way to monitor hemodynamics at the bedside has evolved considerably in the intensive care unit as well as in the operating room. The most important evolution has been the declining use of the pulmonary artery catheter along with the growing use of echocardiography and of

  16. Clinical monitoring of systemic hemodynamics in critically ill newborns.

    NARCIS (Netherlands)

    Boode, W.P. de

    2010-01-01

    Circulatory failure is a major cause of mortality and morbidity in critically ill newborn infants. Since objective measurement of systemic blood flow remains very challenging, neonatal hemodynamics is usually assessed by the interpretation of various clinical and biochemical parameters. An overview

  17. Effects of perioperative medication on hemodynamics and blood loss

    NARCIS (Netherlands)

    van Haelst, I.M.M.

    2013-01-01

    Intraoperative hemodynamic changes and loss of blood with the associated risk of allogeneic blood transfusion are risk factors for complications in surgical patients. The use of medication in the perioperative period may influence these risk factors and consequently the frequency of complications.

  18. Analysis of hemodynamics of intracranial saccular aneurysms.

    Science.gov (United States)

    Szafrański, Krzysztof

    2007-01-01

    The aim of this paper is to present the impact of artery curvature and neck size of aneurysms on growth rate and effectiveness of treatment of aneurysms. The dynamics of three-dimensional (3D) lateral aneurysms on arteries of different curvature were analysed using Comsol Femlab software. The simulations were performed for both steady as pulsatile flows. The effect of artery curvature and neck size of aneurysms on parameters such as flow velocity, aneurysm wall shear stress, size of the area of blood reaction (impact area) during the cardiac cycle were evaluated as well as relations between the size of impact area and artery curvature or neck size of aneurysms were provided.

  19. Radionuclide assessment of peripheral hemodynamics: a new technique for measurement of forearm blood volume and flow

    Energy Technology Data Exchange (ETDEWEB)

    Todo, Y.; Tanimoto, M.; Yamamoto, T.; Iwasaki, T.

    1986-02-01

    A new peripheral hemodynamic measurement system using /sup 99m/Tc-labeled red blood cells has been developed. This method was carried out on 22 normal subjects, 29 with coronary artery disease, and two with dilated cardiomyopathy. Peripheral hemodynamic indices obtained from this method included forearm blood volume (FBV), venous capacity (FVC), venous capacity index (VCI), blood flow (FBF), and vascular resistance (FVR), and were compared with the central hemodynamic parameters of left ventricular filling pressure (LVFP), cardiac output (CO), and total systemic vascular resistance (TSVR) obtained with an invasive technique. The normal values were FBV 8.54 +/- 2.04 ml/100 ml; FVC 4.54 +/- 1.23 ml/100 ml; VCI 65.5 +/- 3.8%; FBF 4.26 +/- 0.56 ml/100 ml/min; and FVR 20.9 +/- 4.4 mmHg/ml/100 ml/min. These values were in good agreement with the values reported using conventional plethysmography. The 16 patients with congestive heart failure (NYHA Class II or III) showed significantly lower FBV, FVC, and FBF values and significantly higher VCI and FVR values than the healthy subjects. Capacitance vessel parameters (FBV, FVC, and VCI) and LVFP, FBF and CO, and FVR and TSVR each showed significant correlation; reproducibility was also good. The advantages of this method are (a) the detector does not come in contact with the region being measured; (b) it is possible to ascertain the absolute quantity of blood in the tissue; (c) extravasation of the plasma component can be ignored; and (d) data processing is simple.

  20. Increased hippocampal, thalamic, and prefrontal hemodynamic response to an urban noise stimulus in schizophrenia.

    Science.gov (United States)

    Tregellas, Jason R; Ellis, Jamey; Shatti, Shireen; Du, Yiping P; Rojas, Donald C

    2009-03-01

    People with schizophrenia often have difficulty ignoring unimportant noises in the environment. While experimental measures of sensory gating have yielded insight into neurobiological mechanisms related to this deficit, the degree to which these measures reflect the real-world experience of people with schizophrenia is unknown. The goal of this study was to develop a clinically relevant sensory gating paradigm and to assess differences in brain hemodynamic responses during the task in schizophrenia. Thirty-five participants, including 18 outpatients with schizophrenia and 17 healthy comparison subjects, underwent scanning on a 3-T MR system while passively listening to an "urban white noise" stimulus, a mixture of common sounds simulating a busy urban setting, including multiple conversations and events recorded from a neighborhood gathering, music, and talk radio. P50 evoked responses from a typical paired-click sensory gating task also were measured. Listening to the urban white noise stimulus produced robust activation of the auditory pathway in all participants. Activation was observed in the bilateral primary and secondary auditory cortices, medial geniculate nuclei, and inferior colliculus. Greater activation was observed in the schizophrenia patients relative to the comparison subjects in the hippocampus, thalamus, and prefrontal cortex. Higher P50 test/conditioning ratios also were observed in the schizophrenia patients. These evoked responses correlated with hemodynamic responses in the hippocampus and the prefrontal cortex. The finding of greater activation of the hippocampus, thalamus, and prefrontal cortex during a sensory gating task with high face validity further supports the involvement of these brain regions in gating deficits in schizophrenia. This link is strengthened by the observed correlation between evoked responses in the paired-click paradigm and hemodynamic responses in a functional MRI sensory gating paradigm.

  1. Coping behavior and risk and resilience stress factors in French regional emergency medicine unit workers: a cross-sectional survey.

    Science.gov (United States)

    Lala, A I; Sturzu, L M; Picard, J P; Druot, F; Grama, F; Bobirnac, G

    2016-01-01

    The Emergency Department (ED) has the highest workload in a hospital, offering care to patients in their most acute state of illness, as well as comforting their families and tending to stressful situations of the physical and psychological areal. Method. A cross-sectional survey of 366 Emergency Unit staff members including medical doctors, medical residents, medical nurses and ward aids, was undergone. Study participants came from four periphery hospitals in the Moselle Department of Eastern France with similar workforce and daily patient loads statistics. The instruments used were the Perceived Stress Scale PSS-10 and the Brief COPE questionnaire. Conclusions. Perceived work overload and overall stress is strongly related to work hours and tend to have a stronger influence on doctors than on the nursing staff. Substance use is a common coping method for medical interns, consistent with prior research. The regular assessment of the ED staff perception of stress and stress related factors is essential to support organizational decisions in order to promote a better work environment and better patient care.

  2. A biomedical solicitation examination of nanoparticles as drug agents to minimize the hemodynamics of a stenotic channel

    Science.gov (United States)

    Ijaz, S.; Nadeem, S.

    2017-11-01

    A theoretical examination is presented in this analysis to study the flow of a bio-nanofluid through a curved stenotic channel. The curved channel is considered with an overlapping stenotic region. The effect of convective conditions is incorporated to discuss the heat transfer characteristic. The mathematical problem of a curved stenotic channel is formulated and then solved by using the exact technique. To discuss the hemodynamics of a curved stenotic channel the expression of resistance to blood is evaluated by dividing the channel into pre-stenotic, stenotic and post stenotic region. In this investigation gold, silver and copper nanoparticles are used as drug carriers. The outcomes of the graphical illustration reveal that with an increase in nanoparticle concentration hemodynamics effects of stenosed curved channel are reduced and they also conclude that the drug Au nanoparticles are more effective to minimize hemodynamics when compared to the drug Ag and Cu nanoparticles. This analysis finds valuable theoretical information for nanoparticles used as drug agents in the field of bio-inspired applications.

  3. Reliability of oscillometric central hemodynamic responses to an orthostatic challenge.

    Science.gov (United States)

    Stoner, Lee; Bonner, Chantel; Credeur, Daniel; Lambrick, Danielle; Faulkner, James; Wadsworth, Daniel; Williams, Michelle A

    2015-08-01

    Monitoring central hemodynamic responses to an orthostatic challenge may provide important insight into autonomic nervous system function. Oscillometric pulse wave analysis devices have recently emerged, presenting clinically viable options for investigating central hemodynamic properties. The purpose of the current study was to determine whether oscillometric pulse wave analysis can be used to reliably (between-day) assess central blood pressure and central pressure augmentation (augmentation index) responses to a 5 min orthostatic challenge (modified tilt-table). Twenty healthy adults (26.4 y (SD 5.2), 55% F, 24.7 kg/m(2) (SD 3.8)) were tested on 3 different mornings in the fasted state, separated by a maximum of 7 days. Central hemodynamic variables were assessed on the left arm using an oscillometric device. Repeated measures analysis of variance indicated a significant main effect of the modified tilt-table for all central hemodynamic variables (P blood pressure increased by 2.3 (CI: 4.4, 0.16) mmHg, and augmentation index decreased by an absolute - 5.3%, (CI: -2.7, -7.9%). The intra-class correlation coefficient values for central diastolic pressure (0.83-0.86), central systolic blood pressure (0.80-0.87) and AIx (0.79-0.82) were above the 0.75 criterion in both the supine and tilted positions, indicating excellent between-day reliability. Central hemodynamic responses to an orthostatic challenge can be assessed with acceptable between-day reliability using oscillometric pulse wave analysis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Cerebral hemodynamics and metabolism in patients with moyamoya disease not demonstrating either cerebral infarct or hemorrhage on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, Yasuo; Ichiya, Yuichi; Sasaki, Masayuki; Akashi, Yuko; Yoshida, Tsuyoshi; Fukumura, Toshimitsu; Masuda, Kouji; Matsushima, Toshio; Fukui, Masashi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1995-12-01

    We evaluated the cerebral hemodynamics and metabolism in moyamoya patients who did not demonstrate either cerebral infarct or hemorrhage on MRI. The subjects consisted of 5 patients with moyamoya disease (4 females and one male, aged from 15 to 40 ears). The CBF, OEF and CMRO{sub 2} of the moyamoya patients did not differ from those of the normal control subjects. The CBV did increase significantly in the cerebral cortices and striatum, but not in the cerebellum. The TT was also significantly prolonged in the frontal and parietal regions. The cerebrovascular CO{sub 2} response was markedly impaired in the frontal, temporal and parietal cortices. However, it was relatively preserved in the occipital cortex, thalamus and cerebellum. Thus, the cerebral hemodynamic reserve capacity decreased even in the moyamoya patients not demonstrating either cerebral infarct or hemorrhage on MRI, and it should be considered in the management of these patients. (author).

  5. Spatial heterogeneity of the structure and stress field in Hyuga-nada region, southwest Japan, deduced from onshore and offshore seismic observations

    Science.gov (United States)

    Uehira, K.; Yakiwara, H.; Yamada, T.; Umakoshi, K.; Nakao, S.; Kobayashi, R.; Goto, K.; Miyamachi, H.; Mochizuki, K.; Nakahigashi, K.; Shinohara, M.; Kanazawa, T.; Hino, R.; Goda, M.; Shimizu, H.

    2010-12-01

    In Hyuga-nada region, the Philippine Sea (PHS) plate is subducting beneath the Eurasian (EU) plate (the southwest Japan arc) along the Nankai trough at a rate of about 5 cm per year. The seismic activity in the boundary between the PHS and the Eurasian (EU) plates varies spatially along the Nankai trough. Especially the region from off coast of Shikoku to the Bungo channel and Hyuga-nada has large variation of seismicity. Although usual microearthquake activity is active in Hyuga-nada, it is inactive near Shikoku. On the other hand, although the great earthquake (M>8) has occurred repeatedly in near Shikoku at intervals of about 100 years, in Hyuga-nada, smaller earthquakes (M7 class) has occurred at intervals of about dozens of years, and so plate coupling varies dozens of kilometers specially. Big earthquakes (M7 class) have occurred in the north region from latitude 31.6 degrees north, but it has not occurred in the south region from latitude 31.6 degrees north. The largest earthquake ever recorded in Hyuga-nada region is the 1968 Hyuga-nada earthquake (Mw 7.5). And microseismicity varies spatially. It is important to understand seismic activity, stress field, and structure in such region in order to understand seismic cycle. We performed extraordinary seismic observation in and around Hyuga-nada region. More than 20 pop-up type OBSs were deployed above hypocentral region of Hyuga-nada using Nagasaki-maru and several data loggers were deployed in order to compensate a regular seismic network on land. We detected earthquakes more than 2 times of JMA. Seismic activity in source region of the 1961 Hyuga-nada Earthquake (M7.0) is low, but around its source region, seismic activity is very high. In order to obtain a 3D seismic velocity structure and precise hypocenter distribution and focal mechanisms around the Hyuga-nada region, we used Double-Difference (DD) Tomography method developed by Zhang and Thurber (2003). We could detect the structure of subduction of

  6. Understanding water deficit stress-induced changes in the basic metabolism of higher plants - biotechnologically and sustainably improving agriculture and the ecoenvironment in arid regions of the globe.

    Science.gov (United States)

    Shao, Hong-Bo; Chu, Li-Ye; Jaleel, C Abdul; Manivannan, P; Panneerselvam, R; Shao, Ming-An

    2009-01-01

    Water is vital for plant growth, development and productivity. Permanent or temporary water deficit stress limits the growth and distribution of natural and artificial vegetation and the performance of cultivated plants (crops) more than any other environmental factor. Productive and sustainable agriculture necessitates growing plants (crops) in arid and semiarid regions with less input of precious resources such as fresh water. For a better understanding and rapid improvement of soil-water stress tolerance in these regions, especially in the water-wind eroded crossing region, it is very important to link physiological and biochemical studies to molecular work in genetically tractable model plants and important native plants, and further extending them to practical ecological restoration and efficient crop production. Although basic studies and practices aimed at improving soil water stress resistance and plant water use efficiency have been carried out for many years, the mechanisms involved at different scales are still not clear. Further understanding and manipulating soil-plant water relationships and soil-water stress tolerance at the scales of ecology, physiology and molecular biology can significantly improve plant productivity and environmental quality. Currently, post-genomics and metabolomics are very important in exploring anti-drought gene resources in various life forms, but modern agriculturally sustainable development must be combined with plant physiological measures in the field, on the basis of which post-genomics and metabolomics have further practical prospects. In this review, we discuss physiological and molecular insights and effects in basic plant metabolism, drought tolerance strategies under drought conditions in higher plants for sustainable agriculture and ecoenvironments in arid and semiarid areas of the world. We conclude that biological measures are the bases for the solutions to the issues relating to the different types of

  7. Hemodynamic Evaluation of a Biological and Mechanical Aortic Valve Prosthesis Using Patient-Specific MRI-Based CFD.

    Science.gov (United States)

    Hellmeier, Florian; Nordmeyer, Sarah; Yevtushenko, Pavlo; Bruening, Jan; Berger, Felix; Kuehne, Titus; Goubergrits, Leonid; Kelm, Marcus

    2017-08-29

    Modeling different treatment options before a procedure is performed is a promising approach for surgical decision making and patient care in heart valve disease. This study investigated the hemodynamic impact of different prostheses through patient-specific MRI-based CFD simulations. Ten time-resolved MRI data sets with and without velocity encoding were obtained to reconstruct the aorta and set hemodynamic boundary conditions for simulations. Aortic hemodynamics after virtual valve replacement with a biological and mechanical valve prosthesis were investigated. Wall shear stress (WSS), secondary flow degree (SFD), transvalvular pressure drop (TPD), turbulent kinetic energy (TKE), and normalized flow displacement (NFD) were evaluated to characterize valve-induced hemodynamics. The biological prostheses induced significantly higher WSS (medians: 9.3 vs. 8.6 Pa, P = 0.027) and SFD (means: 0.78 vs. 0.49, P = 0.002) in the ascending aorta, TPD (medians: 11.4 vs. 2.7 mm Hg, P = 0.002), TKE (means: 400 vs. 283 cm2 /s2 , P = 0.037), and NFD (means: 0.0994 vs. 0.0607, P = 0.020) than the mechanical prostheses. The differences between the prosthesis types showed great inter-patient variability, however. Given this variability, a patient-specific evaluation is warranted. In conclusion, MRI-based CFD offers an opportunity to assess the interactions between prosthesis and patient-specific boundary conditions, which may help in optimizing surgical decision making and providing additional guidance to clinicians. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  8. In-situ investigation of the influence of the long-term shear strength of faults on the regional stress field in a granite rock mass

    Science.gov (United States)

    Figueiredo, Bruno; Cornet, Francois; Lamas, Luís; Muralha, José

    2016-04-01

    A case study is presented to show how stress field measurements may be used to assess the long-term rheological behaviour of an equivalent geo-material. The example concerns a granitic rock mass at the km3 scale, where an underground hydropower scheme including a new 10 km long power conduit and a powerhouse complex will be constructed. For design of the underground cavern and hydraulic pressure tunnel, several in situ stress measurements were carried out, using hydraulic borehole testing, overcoring and flat jack techniques. A first continuum mechanics model, with a homogenous material, was developed to integrate the several in situ test results and to assess the regional stress field. This model is based on elasticity and relaxation of the elastic properties measured through laboratory tests conducted on cores. Results of integration show that the long-term behavior of this granite rock mass differs markedly from the short-term behaviour as defined by laboratory tests. This suggests that the in-situ stress field depends mostly on the softer material that fills up the faults and hence results from the shear stress relaxation over a large number of pre-existing fractures and faults. A second continuum mechanics model, with consideration of two fault planes located nearby the hydraulic tests, was studied. This model is based on elasticity for the overall rock mass, with the elastic properties extracted from laboratory measurements, and visco-elasticity with small long-term shear strength for the two fault planes. Results show that the overall granite rock mass may be viewed as a combination of stiff elastic blocks separated by soft low strength material, leading to a fairly large scale homogeneous axisymmetrical stress field with vertical axis. Advantages and limitations of the two modelling approaches are discussed.

  9. Chronologic Evaluation of Cerebral Hemodynamics by Dynamic Susceptibility Contrast Magnetic Resonance Imaging After Indirect Bypass Surgery for Moyamoya Disease.

    Science.gov (United States)

    Ishii, Yosuke; Tanaka, Yoji; Momose, Toshiya; Yamashina, Motoshige; Sato, Akihito; Wakabayashi, Shinichi; Maehara, Taketoshi; Nariai, Tadashi

    2017-12-01

    Although indirect bypass surgery is an effective treatment option for patients with ischemic-onset moyamoya disease (MMD), the time point after surgery at which the patient's hemodynamic status starts to improve and the time point at which the improvement reaches a maximum have not been known. The objective of the present study is to evaluate the hemodynamic status time course after indirect bypass surgery for MMD, using dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI). We retrospectively analyzed the cases of 25 patients with MMD (37 sides; mean age, 14.7 years; range, 3-36 years) who underwent indirect bypass surgery and repeated DSC-MRI measurement within 6 months after the operation. The difference in the mean transit time (MTT) between the target regions and the control region (cerebellum) was termed the MTT delay, and we measured the MTT delay's chronologic changes after surgery. The postoperative MTT delay was 1.81 ± 1.16 seconds within 1 week after surgery, 1.57 ± 1.01 at weeks 1-2, 1.55 ± 0.68 at weeks 2-4, 1.32 ± 0.68 at months 1-2, 0.95 ± 0.32 at months 2-3, and 0.77 ± 0.33 at months 3-6. Compared with the preoperative value (2.11 ± 0.98 seconds), the MTT delay decreased significantly from 2 to 4 weeks after surgery (P < 0.05). The amelioration of cerebral hemodynamics by indirect bypass surgery began soon after surgery and gradually reached a maximum at 3 months after surgery. DSC-MRI detected small changes in hemodynamic improvement, which are suspected to be caused by the initiation of angiogenesis and arteriogenesis in the early postoperative period. Copyright © 2017. Published by Elsevier Inc.

  10. MiRNAs regulate oxidative stress related genes via binding to the 3' UTR and TATA-box regions: a new hypothesis for cataract pathogenesis.

    Science.gov (United States)

    Wu, Changrui; Liu, Zhao; Ma, Le; Pei, Cheng; Qin, Li; Gao, Ning; Li, Jun; Yin, Yue

    2017-08-14

    Age-related cataracts are related to oxidative stress. However, the genome-wide screening of cataract related oxidative stress related genes are not thoroughly investigated. Our study aims to identify cataract regulated miRNA target genes that are related to oxidative stress and to propose a new possible mechanism for cataract formation. Microarrays were used to determine the mRNA expression profiles of both transparent and cataractous lenses. The results were analyzed by significance analyses performed by the microarray software, and bioinformatics analysis was further conducted using Molecular Annotation System. The Eukaryotic Promoter Database (EPD) was used to retrieve promoter sequences and identify TATA-box motifs. Online resource miRWalk was exploited to screen for validated miRNAs targeting mRNAs related to oxidative stress. RNAhybrid online tool was applied to predict the binding between significantly regulated miRNAs in cataract lenses and target mRNAs. Oxidative stress pathway was significantly regulated in cataractous lens samples. Pro-oxidative genes were half up-regulated (11/20), with a small number of genes down-regulated (4/20) and the rest of them with no significant change (5/20). Anti-oxidative genes were partly up-regulated (17/69) and partly down-regulated (17/69). Four down-regulated miRNAs (has-miR-1207-5p, has-miR-124-3p, has-miR-204-3p, has-miR-204-5p) were found to target 3' UTR of pro-oxidative genes and could also bind to the TATA-box regions of anti-oxidative genes (with the exception of has-miR-204-3p), whilst two up-regulated miRNAs (has-miR-222-3p, has-miR-378a-3p) were found to target 3' UTR of anti-oxidative genes and could simultaneously bind to the TATA-box regions of pro-oxidative genes. We propose for the first time a hypothesis that cataract regulated miRNAs could contribute to cataract formation not only by targeting 3' UTR but also by targeting TATA-box region of oxidative stress related genes. This results in the

  11. Hemodynamic energy dissipation in the cardiovascular system: generalized theoretical analysis on disease states.

    Science.gov (United States)

    Dasi, Lakshmi P; Pekkan, Kerem; de Zelicourt, Diane; Sundareswaran, Kartik S; Krishnankutty, Resmi; Delnido, Pedro J; Yoganathan, Ajit P

    2009-04-01

    We present a fundamental theoretical framework for analysis of energy dissipation in any component of the circulatory system and formulate the full energy budget for both venous and arterial circulations. New indices allowing disease-specific subject-to-subject comparisons and disease-to-disease hemodynamic evaluation (quantifying the hemodynamic severity of one vascular disease type to the other) are presented based on this formalism. Dimensional analysis of energy dissipation rate with respect to the human circulation shows that the rate of energy dissipation is inversely proportional to the square of the patient body surface area and directly proportional to the cube of cardiac output. This result verified the established formulae for energy loss in aortic stenosis that was solely derived through empirical clinical experience. Three new indices are introduced to evaluate more complex disease states: (1) circulation energy dissipation index (CEDI), (2) aortic valve energy dissipation index (AV-EDI), and (3) total cavopulmonary connection energy dissipation index (TCPC-EDI). CEDI is based on the full energy budget of the circulation and is the proper measure of the work performed by the ventricle relative to the net energy spent in overcoming frictional forces. It is shown to be 4.01+/-0.16 for healthy individuals and above 7.0 for patients with severe aortic stenosis. Application of CEDI index on single-ventricle venous physiology reveals that the surgically created Fontan circulation, which is indeed palliative, progressively degrades in hemodynamic efficiency with growth (pindex to gauge the hemodynamic severity of stenosed aortic valves as it accurately reflects energy loss. It is about 0.28+/-0.12 for healthy human valves. Moderate aortic stenosis has an AV-EDI one order of magnitude higher while clinically severe aortic stenosis cases always had magnitudes above 3.0. TCPC-EDI represents the efficiency of the TCPC connection and is shown to be negatively

  12. Hemodynamic and neuropathological analysis in rats with aluminum trichloride-induced Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Szu-Ming Chen

    Full Text Available BACKGROUND AND AIMS: Hemodynamic normality is crucial to maintaining the integrity of cerebral vessels and, therefore, preserving the cognitive functions of Alzheimer's disease patients. This study investigates the implications of the hemodynamic changes and the neuropathological diversifications of AlCl3-induced AD. METHODS: The experimental animals were 8- to 12-wk-old male Wistar rats. The rats were randomly divided into 2 groups: a control group and a (+control group. Food intake, water intake, and weight changes were recorded daily for 22 wk. Synchronously, the regional cerebral blood flow (rCBF of the rats with AlCl3-induced AD were measured using magnetic resonance imaging (MRI. The hemorheological parameters were analyzed using a computerized auto-rotational rheometer. The brain tissue of the subjects was analyzed using immunohistological chemical (IHC staining to determine the beta-amyloid (Aβ levels. RESULTS: The results of hemodynamic analysis revealed that the whole blood viscosity (WBV, fibrinogen, plasma viscosity and RBC aggregation index (RAI in (+control were significantly higher than that of control group, while erythrocyte electrophoresis (EI of whole blood in (+control were significantly lower than that of control group. The results of acetylcholinesterase-RBC (AChE-RBCin the (+control group was significantly higher than that of the control group. The results also show that the reduction of rCBF in rats with AlCl3-induced AD was approximately 50% to 60% that of normal rats. IHC stain results show that significantly more Aβ plaques accumulated in the hippocampus and cortex of the (+control than in the control group. CONCLUSION: The results accentuate the importance of hemorheology and reinforce the specific association between hemodynamic and neuropathological changes in rats with AlCl3-induced AD. Hemorheological parameters, such as WBV and fibrinogen, and AChE-RBC were ultimately proven to be useful biomarkers of the

  13. Incidence and hemodynamic characteristics of near-fainting in healthy 6- to 16-year old subjects.

    Science.gov (United States)

    de Jong-de Vos van Steenwijk, C C; Wieling, W; Johannes, J M; Harms, M P; Kuis, W; Wesseling, K H

    1995-06-01

    We studied the incidence and hemodynamic characteristics of near-fainting under orthostatic stress in healthy children and teenagers. Orthostatic stress testing is increasingly used to identify young subjects with unexplained syncope. However, the associated incidence of syncope and hemodynamic responses in normal young subjects are not well known. Eighty-four healthy subjects 6 to 16 years old performed forced breathing, stand-up and 70 degrees tilt-up tests. An intravenous line to sample blood for biochemical assessment of sympathetic function was introduced between the stand-up and tilt-up tests. Finger arterial pressure was measured continuously. Left ventricular stroke volume was computed from the pressure pulsations. Sixteen of the 84 subjects were excluded because of technical problems. The incidence of a near-fainting response in the remaining 68 subjects was 10% (7 of 68) for the stand-up test and 40% (29 of 68) for the tilt-up test. Baseline parasympathetic and sympathetic activity of nonfainting and near-fainting subjects was not different. Near-fainting was characterized by attenuated systemic vasoconstriction and exaggerated tachycardia that occurred as early as 1 min after return to the upright position. On tilt-up, plasma adrenaline levels increased by a factor of 2, with slightly higher increments in the near-fainting subjects. Inadequate vasoconstriction is the common underlying mechanism of near-fainting in young subjects. The remarkably high incidence of near-fainting during the tilt-up test after intravascular instrumentation raises serious doubts about the utility of this procedure in evaluating syncope of unknown origin in young subjects.

  14. Automatic measurement and visualization of focal femoral cartilage thickness in stress-based regions of interest using three-dimensional knee models.

    Science.gov (United States)

    Pitikakis, Marios; Chincisan, Andra; Magnenat-Thalmann, Nadia; Cesario, Lorenzo; Parascandolo, Patrizia; Vosilla, Loris; Viano, Gianni

    2016-05-01

    Thinning of cartilage is a common manifestation of osteoarthritis. This study addresses the need of measuring the focal femoral cartilage thickness at the weight- bearing regions of the knee by developing a reproducible and automatic method from MR images. 3D models derived from semiautomatic MR image segmentations were used in this study. Two different methods were examined for identifying the mechanical loading of the knee articulation. The first was based on a generic weight-bearing regions definition, derived from gait characteristics and cadaver studies. The second used a physically based simulation to identify the patient-specific stress distribution of the femoral cartilage, taking into account the forces and movements of the knee. For this purpose, four different scenarios were defined in our 3D finite element (FE) simulations. The radial method was used to calculate the cartilage thickness in stress-based regions of interest, and a study was performed to validate the accuracy and suitability of the radial thickness measurements. Detailed focal maps using our simulation data and regional measurements of cartilage thickness are given. We present the outcome of the different simulation scenarios and discuss how the internal/external rotations of the knee alter the overall stress distribution and affect the shape and size of the calculated weight-bearing areas. The use of FE simulations allows for a patient-specific calculation of the focal cartilage thickness. It is important to assess the quantification of focal knee cartilage morphology to monitor the progression of joint diseases or related treatments. When this assessment is based on MR images, accurate and robust tools are required. In this paper, we presented a set of techniques and methodologies in order to accomplish this goal and move toward personalized medicine.

  15. Changes in regional brain monoaminergic activity and temporary down-regulation in stress response from dietary supplementation with l-tryptophan in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Basic, Dean; Schjolden, Joachim; Krogdahl, Ashild; von Krogh, Kristine; Hillestad, Marie; Winberg, Svante; Mayer, Ian; Skjerve, Eystein; Höglund, Erik

    2013-06-28

    The brain monoamines serotonin (5-hydroxytryptamine; 5-HT) and dopamine (DA) both play an integrative role in behavioural and neuroendocrine responses to challenges, and comparative models suggest common mechanisms for dietary modulation of transmission by these signal substances in vertebrates. Previous studies in teleosts demonstrate that 7 d of dietary administration with L-tryptophan (Trp), the direct precursor of 5-HT, suppresses the endocrine stress response. The present study investigated how long the suppressive effects of a Trp-enriched feed regimen, at doses corresponding to two, three or four times the Trp levels in commercial feed, last in juvenile Atlantic cod (Gadus morhua) when the fish are reintroduced to a diet with standard amino acid composition. We also wanted to determine whether Trp supplementation induced changes in brain monoaminergic neurochemistry in those forebrain structures innervated by DA and 5-HTergic neurons, by measuring regional activity of DA and 5-HT in the lateral pallial regions (Dl) of the telencephalon and nucleus lateralis tuberis (NLT) of the hypothalamus. Dietary Trp resulted in a dose-dependent suppression in plasma cortisol among fish exposed to confinement stress on the first day following experimental diet; however, such an effect was not observed at 2 or 6 d after Trp treatment. Feeding the fish with moderate Trp doses also evoked a general increase in DA and 5-HT-ergic activity, suggesting that these neural circuits within the NLT and Dl may be indirectly involved in regulating the acute stress response.

  16. The Alterations of IL-1Beta, IL-6, and TGF-Beta Levels in Hippocampal CA3 Region of Chronic Restraint Stress Rats after Electroacupuncture (EA Pretreatment

    Directory of Open Access Journals (Sweden)

    Tianwei Guo

    2014-01-01

    Full Text Available Immunological reactions induced by proinflammatory cytokines have been involved in the pathogenesis of depressive disorders. Recent studies showed that Electroacupuncture (EA was able to reduce depressive symptoms; however, the underlying mechanism and its potential targets remain unknown. In the present study, we used a 21-day chronic restraint stress rats as a model to investigate how EA could alleviate depression. Open field test was carried out to evaluate the depressive symptoms at selected time points. At the end of study, immunohistochemistry (IHC was performed to detect the expressions of IL-1beta, IL-6, and TGF-beta in hippocampal CA3 region. We found that chronic restraint stress significantly decreased behavioral activities, whereas EA stimulation at points Baihui (GV 20 and Yintang (GV 29 showed protective effect during the test period. In addition, the IL-1beta, IL-6, and TGF-beta increased in rats exposed to chronic restraint stress, while EA downregulated the levels of IL-1beta and IL-6. These findings implied that EA pretreatment could alleviate depression through modulating IL-1beta and IL-6 expression levels in hippocampal CA3 region.

  17. Toluene effects on Oxidative Stress in Brain regions of Young-adult, Middleage,and Senescent Brown Norway Rats

    Science.gov (United States)

    The influence of aging on susceptibility to environmental contaminants is not well understood. To extend knowledge in this area, we examined effects in rat brain of the volatile organic compound toluene. The objective was to test whether oxidative stress plays a role in the adver...

  18. TOLUENE EFFECTS ON OXIDATIVE STRESS IN BRAIN REGIONS OF YOUNG-ADULT, MIDDLE-AGE AND SENESCENT BROWN NORWAY RATS

    Science.gov (United States)

    Aging-related susceptibility to environmental chemicals is poorly understood. Oxidative stress (OS) appears to play an important role in susceptibility and disease in old age. The objectives of this study, therefore, were to test whether OS is a potential toxicity pathway for tol...

  19. Periodontal conditions and oral hygiene in rural population of post-war Vukovar region, Croatia in correlation to stress.

    Science.gov (United States)

    Spalj, Stjepan; Plancak, D; Bozic, D; Kasaj, A; Willershausen, B; Jelusic, D

    2008-03-31

    The greatest burden of oral diseases is on the socially marginalized population, such as those living in small villages and war areas. The aim of this study was to assess the periodontal conditions of people in post-war area villages in relation to oral hygiene, habits and war stress. The study was conducted on a sample of 282 subjects (mean age 41.5 +/- 17.8) in seven Vukovar villages using the questionnaire and clinical periodontal examination. Five years after the war in Croatia the population was still very poor, low educated, and had a low level of periodontal health and oral hygiene habits. The level of periodontal disease and attachment loss tended to increase with age and physical activity and decrease with education level, higher frequency of tooth brushing and toothbrush replacement, dental visits and utilisation of auxiliary devices. Subjects exposed to any kind of war stress had a significantly worse periodontal status and more excluded sextants than those who were not exposed to such stress experience (pwar, wounded or lost a dear person (pwar rarely brushed their teeth, visited dentist and changed toothbrushes, but more frequently drank alcohol and smoked, in comparison to other groups, especially those who have not been exposed to war stress. Specific socio-economic and psychological conditions in post-war areas could be significant risk factors for poor periodontal conditions.

  20. Evaluation of plain radiograph in mitral stenosis related to hemodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Ku Ok; Suh, Jung Ho; Park, Chang Yun; Choi, Byung So [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1973-04-15

    Mitral stenosis, the most frequent heart disease in adult, showed relatively characteristic pulmonary findings in plain chest X-ray. In recent years the knowledge of the altered physiology of hemodynamics could offer considerable amount of hemodynamic barrier in plain chest. But the value of several parameters was still controversial. In this study a variety of roentgen signs were related to physiologic data and those were acquired by the cardiac catheterization in total of 67 cases of mitral stenosis. 1. Correlation of DPA/DHT ratio (Diameter of pulmonary arterial segment/ Diameter of hemithorax X 100) to hemodynamic data; The pulmonary arterial segments was dilated by two factors, the one was pulmonary blood flow and the other the blood pressure within it. In mitral stenosis, the cardiac output was decreased to quite uniform level, hence measurement of pulmonary arterial segment might be valuable. The correlation coefficient of DPA/ DHT ratio to hemodynamic data were as follows: 0.54 to mean pulmonary artery pressure, 0.32 to pulmonary capillary wedge pressure, -0.37 to mitral valvular area and 0.07 to pulmonary vascular resistance. No significant difference was noted in between pure mitral stenosis and mitral stenosis associated with other valvular disease. 2. Correlation of diameter of right descending pulmonary artery to hemodynamic data: The measurement was made near the first bifurcation of right descending pulmonary artery at its widest point. Pulmonary vascular pattern was best correlated (r=0.71). Another had rough correlation: 0.05 to mean pulmonary artery pressure, 0.31 to pulmonary capillary wedge pressure, -0.44 to mitral valvular area in correlation coefficient. No pulmonary arterial hypertension was observed in the cases diameter of less than 12 mm, but all except two cases had pulmonary hypertension in which diameter exceeded 16 mm. According to increase of the mean pulmonary arterial pressure, the same increment in pressure increased change

  1. Differential effect of the 5-HTT gene-linked polymorphic region on emotional eating during stress exposure following tryptophan challenge.

    Science.gov (United States)

    Markus, C Rob; Verschoor, Ellen; Smeets, Tom

    2012-04-01

    Stress and negative moods, which are thought to be partly mediated by reduced brain serotonin function, often increase emotional eating in dieting women (restrainers). Because the short (S) allele polymorphism in the serotonin transporter gene (5-HTTLPR) is associated with serotonin dysfunction, S allele compared to long (L) allele 5-HTTLPR genotypes may be more susceptible to stress-induced emotional eating. Consequently, serotonin challenge via tryptophan (TRP)-rich protein hydrolysate (TPH) may alleviate stress-induced emotional eating particularly in S/S allele carriers. We tested whether acute stress affects emotional eating in women with high or low dietary restraints depending on their 5-HTTLPR genotype and TPH intake. Nineteen female subjects who were homozygous for the short-allele 5-HTTLPR genotype (S'/S'=S/L(G), L(G)/L(G): restrainers vs. nonrestrainers) and 23 female subjects who were homozygous for the long-allele 5-HTTLPR genotype (L'/L'=L(A)/L(A): restrainers vs. nonrestrainers) were tested in a double-blind, placebo-controlled crossover study of stress-induced emotional eating following intake of TPH or a placebo. TPH intake significantly increased the plasma TRP/large neutral amino acid ratio (Pstress-induced negative mood (P=.037) and the desire for sweet, high-fat foods (P=.011) regardless of dietary restraint. Since TPH caused a greater increase in the plasma TRP/large neutral amino acid ratio in the L'/L' group compared to S'/S' group, the exclusive beneficial effects of L'/L' genotype may be due to enhanced brain 5-HT function. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Co-occurrence patterns along a regional aridity gradient of the subtropical Andes do not support stress gradient hypotheses.

    Directory of Open Access Journals (Sweden)

    Ramiro Pablo López

    Full Text Available The stress gradient hypothesis posits that facilitation and stress are positively correlated. The hump-shaped hypothesis, on the contrary, proposes that facilitation is greater at intermediate stress levels. The relationship between facilitation and environmental stress is commonly studied at small spatial scales and/or considering few species; thus, the implications of facilitation at a community level remain poorly understood. Here, we analyzed local co-occurrence patterns of all plant species at 25 sites within the subtropical Andes to evaluate the role of facilitation and competition as drivers of community structure. We considered a wide latitudinal gradient (19-26°S that incorporates great variation in aridity. No previous studies have attempted to study these patterns across such a broad scale in warm deserts. Each locality was sampled at two scales (quadrat and patch, and co-occurrence was analyzed via null models. Furthermore, we tested for a relationship between plant co-occurrences and environmental aridity. Resulting patterns depended on life form. When all species were considered, negative associations were found, indicating competition. Woody/cactus life forms tended to be associated across communities, suggesting that there is facilitation between these life forms. Additionally, and unlike previous studies, we found positive associations among shrubs. The strength of the association between woody species changed non-monotonically with aridity. Herbs showed an inverted hump-shaped relationship, albeit ranging mostly among neutral values. Independent of the association type exhibited by different life forms, our community level results do not support current stress gradient hypotheses.

  3. A method for discriminating systemic and cortical hemodynamic changes by time domain fNIRS

    Science.gov (United States)

    Zucchelli, Lucia; Spinelli, Lorenzo; Contini, Davide; Re, Rebecca; Torricelli, Alessandro

    2013-06-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical technique able to measure hemodynamic response in the brain cortex. Among the different approaches the fNIRS can be based on, the time resolved one allows a straightforward relationship between the photon detection time and its path within the medium, improving the discrimination of the information content relative to the different layers the tissues are composed of. Thus absorption and scattering properties of the probed tissue can be estimated, and from them the oxy- and deoxy-hemoglobin concentration. However, an open issue in the optical imaging studies is still the accuracy in separating the superficial hemodynamic changes from those happening in deeper regions of the head and more likely involving the cerebral cortex. In fact a crucial point is the precise estimate of the time dependent pathlength spent by photons within the perturbed medium. A novel method for the calculus of the absorption properties in time domain fNIRS, based on a refined computation of photon pathlength in multilayered media, is proposed. The method takes into account the non-ideality of the measurement system (its instrument response function) and the heterogeneous structure of the head. The better accuracy in computing the optical pathlength can improve the NIRS data analysis, especially for the deeper layer. Simulations and preliminary analysis on in vivo data have been performed to validate the method and are here presented.

  4. CFD and PIV analysis of hemodynamics in a growing intracranial aneurysm.

    Science.gov (United States)

    Raschi, Marcelo; Mut, Fernando; Byrne, Greg; Putman, Christopher M; Tateshima, Satoshi; Viñuela, Fernando; Tanoue, Tetsuya; Tanishita, Kazuo; Cebral, Juan R

    2012-02-01

    Hemodynamics is thought to be a fundamental factor in the formation, progression, and rupture of cerebral aneurysms. Understanding these mechanisms is important to improve their rupture risk assessment and treatment. In this study, we analyze the blood flow field in a growing cerebral aneurysm using experimental particle image velocimetry (PIV) and computational fluid dynamics (CFD) techniques. Patient-specific models were constructed from longitudinal 3D computed tomography angiography images acquired at 1-y intervals. Physical silicone models were constructed from the computed tomography angiography images using rapid prototyping techniques, and pulsatile flow fields were measured with PIV. Corresponding CFD models were created and run under matching flow conditions. Both flow fields were aligned, interpolated, and compared qualitatively by inspection and quantitatively by defining similarity measures between the PIV and CFD vector fields. Results showed that both flow fields were in good agreement. Specifically, both techniques provided consistent representations of the main intra-aneurysmal flow structures and their change during the geometric evolution of the aneurysm. Despite differences observed mainly in the near wall region, and the inherent limitations of each technique, the information derived is consistent and can be used to study the role of hemodynamics in the natural history of intracranial aneurysms.

  5. Echocardiographic Monitoring of Intracardiac Hemodynamics in Neonatal Respiratory Distress Syndrome

    Directory of Open Access Journals (Sweden)

    S. A. Perepelitsa

    2010-01-01

    Full Text Available Objective: to perform an early neonatal ultrasound study of intracardiac hemodynamics in premature neonates with respiratory distress syndrome (RDS during mechanical ventilation. Subjects and methods. The paper presents the results of ultrasound study of intracardiac hemodynamics in 51 premature neonates. Two patient groups were identified. Group 1 comprised 34 infants with severe RDS who received the exogenous surfactant Curosurf and Group 2 consisted of 17 apparently healthy premature newborn infants. Results. Functional tension of the cardiovascular system was characterized for premature neonates with RDS. There were signs of left ventricular systolic dysfunction within the first 24 hours of life and those of right ventricular dysfunction by day 5 of postnatal age. Within 5 days of life, there were echocardiographic signs of pump dysfunction of both ventricles: stroke volume, cardiac index, and blood minute volume. Analysis of changes in peak blood flow velocity and peak pressure gradient across the atrioventricular valves of the right and left ventricles indicated that 17.6% of the children showed increases in peak blood flow velocity and tricuspid valve pressure gradient in the systolic phase. The greatest peak blood flow velocity changes were recorded in the pulmonary artery trunk. By day 5 of life, signs of pulmonary hypertension concurrent with hydropericardium remained in 29.4% of cases. RDS – was shown to be accompanied by higher Qp/Qs ratio in premature neonates. The lower index was attended by the alleviated signs of respiratory failure. In RDS, mainly left-to-right blood shunt was accomplished through the open oval window, but the shunt intensity decreased when the pathological process was resolved in the lung. The functioning patent ductus arteriosus was hemodynami-cally significant in none case. Conclusion. The premature neonates with RDS were found to have intracardiac hemo-dynamic changes. By day 5 of postnatal age, there was

  6. A comparison of families of children with autism spectrum disorders in family daily routines, service usage, and stress levels by regionality.

    Science.gov (United States)

    McAuliffe, Tomomi; Vaz, Sharmila; Falkmer, Torbjörn; Cordier, Reinie

    2017-11-01

    To explore whether family routines, service usage, and stress levels in families of children with autism spectrum disorder differ as a function of regionality. Secondary analysis of data was undertaken from 535 surveys. Univariate and multivariate analyses were performed to investigate differences between families living in densely populated (DP) areas and less densely populated (LDP) areas. Families living in LDP areas were found to: (1) have reduced employment hours (a two-parent household: Exp (B) = 3.48, p < .001, a single-parent household: Exp (B) = 3.32, p = .011); (2) travel greater distance to access medical facilities (Exp (B) = 1.27, p = .006); and (3) report less severe stress levels (Exp (B) = 0.22, p = .014). There were no differences in family routines; however, flexible employment opportunities and travel distance to medical services need to be considered in families living in LDP areas.

  7. Combined In Silico and In Vitro Approach Predicts Low Wall Shear Stress Regions in a Hemofilter that Correlate with Thrombus Formation In Vivo.

    Science.gov (United States)

    Buck, Amanda K W; Groszek, Joseph J; Colvin, Daniel C; Keller, Sara B; Kensinger, Clark; Forbes, Rachel; Karp, Seth; Williams, Phillip; Roy, Shuvo; Fissell, William H

    2017-08-29

    A major challenge in developing blood-contacting medical devices is mitigating thrombogenicity of an intravascular device. Thrombi may interfere with device function or embolize from the device to occlude distant vascular beds with catastrophic consequences. Chemical interactions between plasma proteins and bioengineered surface occur at the nanometer scale; however, continuum models of blood predict local shear stresses that lead to platelet activation or aggregation and thrombosis. Here, an iterative approach to blood flow path design incorporating in silico, in vitro, and in vivo experiments predicted the occurrence and location of thrombi in an implantable hemofilter. Low wall shear stress (WSS) regions identified by computational fluid dynamics (CFD) predicted clot formation in vivo. Revised designs based on CFD demonstrated superior performance, illustrating the importance of a multipronged approach for a successful design process.

  8. Oxidative stress in Complex Regional Pain Syndrome (CRPS): no systemically elevated levels of malondialdehyde, F2-isoprostanes and 8OHdG in a selected sample of patients.

    Science.gov (United States)

    Fischer, Sigrid G L; Perez, Roberto S G M; Nouta, Jan; Zuurmond, Wouter W A; Scheffer, Peter G

    2013-04-10

    Exaggerated inflammation and oxidative stress are involved in the pathogenesis of Complex Regional Pain Syndrome (CRPS). However, studies assessing markers for oxidative stress in CRPS patients are limited. In this study, markers for lipid peroxidation (malondialdehyde and F2-isoprostanes) and DNA damage (8-hydroxy-2-deoxyguanosine) were measured in nine patients (mean age 50.1 ± 17.1 years) with short term CRPS-1 (median 3 months) and nine age and sex matched healthy volunteers (mean age 49.3 ± 16.8 years) to assess and compare the level of oxidative stress. No differences were found in plasma between CRPS patients and healthy volunteers for malondialdehyde (5.2 ± 0.9 µmol/L vs. 5.4 ± 0.5 µmol/L) F2-isoprostanes (83.9 ± 18.7 pg/mL vs. 80.5 ± 12.3 pg/mL) and 8-hydroxy-2-deoxyguanosine (92.6 ± 25.5 pmol/L vs. 86.9 ± 19.0 pmol/L). Likewise, in urine, no differences were observed between CRPS patients and healthy volunteers for F2-isoprostanes (117 ng/mmol, IQR 54.5-124.3 vs. 85 ng/mmol, IQR 55.5-110) and 8-hydroxy-2-deoxyguanosine (1.4 ± 0.7 nmol/mmol vs. 1.4 ± 0.5 nmol/mmol). Our data show no elevation of systemic markers of oxidative stress in CRPS patients compared to matched healthy volunteers. Future research should focus on local sampling methods of oxidative stress with adequate patient selection based on CRPS phenotype and lifestyle.

  9. Preliminary Computational Hemodynamics Study of Double Aortic Aneurysms under Multistage Surgical Procedures: An Idealised Model Study

    Directory of Open Access Journals (Sweden)

    Yosuke Otsuki

    2013-01-01

    Full Text Available Double aortic aneurysm (DAA falls under the category of multiple aortic aneurysms. Repair is generally done through staged surgery due to low invasiveness. In this approach, one aneurysm is cured per operation. Therefore, two operations are required for DAA. However, post-first-surgery rupture cases have been reported. Although the problems involved with managing staged surgery have been discussed for more than 30 years, investigation from a hemodynamic perspective has not been attempted. Hence, this is the first computational fluid dynamics approach to the DAA problem. Three idealized geometries were prepared: presurgery, thoracic aortic aneurysm (TAA cured, and abdominal aortic aneurysm (AAA cured. By applying identical boundary conditions for flow rate and pressure, the Navier-Stokes equation and continuity equations were solved under the Newtonian fluid assumption. Average pressure in TAA was increased by AAA repair. On the other hand, average pressure in AAA was decreased after TAA repair. Average wall shear stress was decreased at the peak in post-first-surgery models. However, the wave profile of TAA average wall shear stress was changed in the late systole phase after AAA repair. Since the average wall shear stress in the post-first-surgery models decreased and pressure at TAA after AAA repair increased, the TAA might be treated first to prevent rupture.

  10. The stressors and stress reactions of the students in junior high school and the regional characteristic of social support : Through a comparison of the junior school students in Okinawa and Fukuoka

    OpenAIRE

    鉄, 拳

    2011-01-01

    This paper examined regional characteristic of stress in junior high school students from Okinawa and Fukuoka. The results showed that the frequency and strength of stressor in Fukuoka is higher than Okinawa. And stress response for students in Fukuoka is higher than for those in Okinawa. It was showed a higher stress reacton in Fukuoka, and students of this population seem to receive more social support. It is thought that it is because they have more experience receiving stressors. There is...

  11. Is hemifacial spasm accompanied by hemodynamic changes detectable by ultrasound?

    Science.gov (United States)

    Perren, Fabienne; Magistris, Michel R

    2014-08-01

    Arterial tortuosity of the posterior circulation compressing the facial nerve induces the ephaptic axono-axonal cross-talk that sparks hemifacial spasm. We sought if a noninvasive method such as color duplex of these arteries might detect hemodynamical changes in this condition. Nine patients with hemifacial spasm, successfully treated with botulinum toxin, were examined with color-coded duplex ultrasound. Mean blood flow velocities of the vertebral, basilar, posterior inferior cerebellar, and anterior inferior cerebellar arteries were measured and side-to-side comparison performed. In all nine patients, the mean blood flow velocity, averaging across the two arteries, was higher on the side of the hemifacial spasm (Fisher's exact p hemifacial spasm. There was no significant association between the mean flow velocity of the vertebral artery and the side of spasm (p = 0.523). Hemifacial spasm also seems to relate to hemodynamic changes, which may be detectable by color duplex imaging.

  12. [The hemodynamic characterization of the diabetic patient with arterial calcifications].

    Science.gov (United States)

    Vega Gómez, M E; Ley Pozo, J; Aldama Figueroa, A; Lima Santana, B; Montalvo Diago, J; Bustillo, C; Fernández Boloña, A; Gutiérrez Jiménez, O; Ramirez Muñoz, O; Martínez Hernández, R

    1993-01-01

    This study was designed to describe the presence of calcifications according to the clinical features of the diabetic patient and the hemodynamics of the calcified arteries. With this purpose, 197 lower limbs from diabetic patients (type I and II) and carbon-hydrate intolerant patients, were studied. In all of the patients, the pressure ratio leg/arm was measured. On the same way, the arterial flow velocity was recorded using the Doppler ultrasonography on the pedia and postero-tibial arteries. The arterial calcifications, evident on the radiography of the foot, were more frequent between the type I patients and the neuro-infections diabetic foot. According to the hemodynamics point of view, we found a trend of association of more pathologic arterial flow velocity curves with the presence of calcifications (specially on the intima layer). It was also remarkable that an arterial incomprensibility was always associated with arterial calcifications.

  13. Optimal control of CPR procedure using hemodynamic circulation model

    Science.gov (United States)

    Lenhart, Suzanne M.; Protopopescu, Vladimir A.; Jung, Eunok

    2007-12-25

    A method for determining a chest pressure profile for cardiopulmonary resuscitation (CPR) includes the steps of representing a hemodynamic circulation model based on a plurality of difference equations for a patient, applying an optimal control (OC) algorithm to the circulation model, and determining a chest pressure profile. The chest pressure profile defines a timing pattern of externally applied pressure to a chest of the patient to maximize blood flow through the patient. A CPR device includes a chest compressor, a controller communicably connected to the chest compressor, and a computer communicably connected to the controller. The computer determines the chest pressure profile by applying an OC algorithm to a hemodynamic circulation model based on the plurality of difference equations.

  14. Quantitative hemodynamic studies in moyamoya disease: A review

    Science.gov (United States)

    Lee, Marco; Zaharchuk, Greg; Guzman, Raphael; Achrol, Achal; Bell-Stephens, Teresa; Steinberg, Gary K.

    2010-01-01

    Moyamoya disease is characterized by a chronic stenoocclusive vasculopathy affecting the terminal internal carotid arteries. The clinical presentation and outcome of moyamoya disease remain varied based on angiographic studies alone, and much work has been done to study cerebral hemodynamics in this group of patients. The ability to measure cerebral blood flow (CBF) accurately continues to improve with time, and with it a better understanding of the pathophysiological mechanisms in patients with moyamoya disease. The main imaging techniques used to evaluate cerebral hemodynamics include PET, SPECT, xenon-enhanced CT, dynamic perfusion CT, MR imaging with dynamic susceptibility contrast and with arterial spin labeling, and Doppler ultrasonography. More invasive techniques include intraoperative ultrasonography. The authors review the current knowledge of CBF in this group of patients and the role each main quantitative method has played in evaluating them, both in the disease state and after surgical intervention. PMID:19335131

  15. Coronary hemodynamic responses during local hemodilution in canine hearts

    Energy Technology Data Exchange (ETDEWEB)

    Crystal, G.J. (Illinois Masonic Medical Center, Chicago (USA))

    1988-03-01

    To evaluate the effect of hemodilution per se on coronary hemodynamics, experiments were performed in 36 anesthetized, open-chest dogs whose left anterior descending coronary artery (LAD) was perfused selectively with either normal arterial blood or arterial blood diluted with lactated Ringer solution. LAD blood flow (CBF) was measured with an electromagnetic flowmeter and its transmural distribution assessed with 15-{mu}m radioactive microspheres. With perfusion pressure normal, graded hemodilution caused progressive, transmurally uniform increases in CBF that showed an nonlinear relationship to inflow hematocrit. Increased peak reactive hyperemic flow and decreased dilator reserve ratio indicated that both reduced viscosity and vasodilation contributed to increased CBF during hemodilution. Hypotension alone reduced CBF, with greater effect in the subendocardium. Additional hemodilution returned CBF to normotensive value, but relative subendocardial hypoperfusion persisted. The present study provides fundamental information on effects of hemodilution on coronary hemodynamics without the systemic responses that complicated previous studies utilizing whole body exchange transfusions.

  16. US media representation of post-traumatic stress disorder: a comparative study of regional newspapers and national newspapers.

    Science.gov (United States)

    Wu, Lu

    2017-06-01

    News media play an important role in introducing and defining PTSD-related issues to the general public as well as framing their social importance and analyzing solutions for policymakers. Compare how coverage of PTSD by larger papers serving general audiences differed from smaller papers catering to communities likely to be affected by the issue. A content analysis of frames and subtopics about PTSD in all newspaper articles published by selected national newspapers and regional newspapers between the year of 2003 and 2014 (N = 426). National newspapers engaged in higher-level policy discussion with greater frequency than regional newspapers, while regional newspapers were more likely to publish stories highlighting the impact of PTSD on individuals and local communities. Furthermore, coverage by regional newspapers used significantly more episodic frames than thematic frames. Both national and regional newspapers increased the amount of coverage on PTSD significantly after the beginning of the Iraq War in 2003. National newspapers and regional newspapers shared similarities in recognizing dominant issues with PTSD but varied in the way of presenting the topics to the public.

  17. Central and peripheral hemodynamics in exercising humans

    DEFF Research Database (Denmark)

    Calbet, J A L; González-Alonso, J; Helge, J W

    2015-01-01

    oxygen demand were 22%, 12%, and 14% higher, respectively, during maximal AC than LP. Trunk VC was reduced to similar values at Wmax. At Wmax, muscle mass-normalized VC and fractional O2 extraction were lower in the arm than the leg muscles. However, this was compensated for during AC by raising...... perfusion pressure to increase O2 delivery, allowing a similar peak VO2 per kg of muscle mass in both extremities. In summary, despite a lower Qpeak during arm cranking the cardiovascular strain is much higher than during leg pedalling. The adjustments of regional conductances during incremental exercise...... during incremental upright arm cranking (AC) and leg pedalling (LP) to exhaustion (Wmax) in nine males. Systemic VC, peak cardiac output (Qpeak) (indocyanine green) and stroke volume (SV) were 18%, 23%, and 20% lower during AC than LP. The mean BP, the rate-pressure product and the associated myocardial...

  18. Finite element approach to study the behavior of fluid distribution in the dermal regions of human body due to thermal stress

    Directory of Open Access Journals (Sweden)

    M.A. Khanday

    2015-10-01

    Full Text Available The human body is a complex structure where the balance of mass and heat transport in all tissues is necessary for its normal functioning. The stabilities of intracellular and extracellular fluids are important physiological factors responsible for homoeostasis. To estimate the effects of thermal stress on the behavior of extracellular fluid concentration in human dermal regions, a mathematical model based on diffusion equation along with appropriate boundary conditions has been formulated. Atmospheric temperature, evaporation rate, moisture concentration and other factors affecting the fluid concentration were taken into account. The variational finite element approach has been employed to solve the model and the results were interpreted graphically.

  19. Hemodynamic Signals Of Mixed Messages During A Social Exchange

    OpenAIRE

    Zucker, Nancy L.; Green, Steven; James P Morris; Kragel, Philip; Pelphrey, Kevin A.; Bulik, Cynthia M.; LaBar, Kevin S.

    2011-01-01

    The present study used functional magnetic resonance imaging (fMRI) to characterize hemodynamic activation patterns recruited when participants view mixed social communicative messages during a common interpersonal exchange. Mixed messages were defined as conflicting sequences of biological motion and facial affect signals that are unexpected within a particular social context (for example, observing the reception of a gift). Across four social vignettes, valenced facial expressions were cros...

  20. Hemodynamics in CHD: mechanical regulation of congenital heart defects

    OpenAIRE

    Yalçın, Hüseyin Çağatay

    2011-01-01

    This is the periodic report for the HEMODYNAMICS IN CHD project, which received funding under the Seventh Framework Programme (FP7). The project will be applying the techniques developed in to a well established animal model for a severe CHD, hypoplastic left heart syndrome, to dissect the contribution of blood flow related forces on this disease. The report includes images generated to study embryonic development of congenital heart defects.

  1. Continuous Hemodynamic Monitoring in Acute Stroke: An Exploratory Analysis

    Directory of Open Access Journals (Sweden)

    Ayan Sen

    2014-07-01

    Full Text Available Introduction: Non-invasive, continuous hemodynamic monitoring is entering the clinical arena. The primary objective of this study was to test the feasibility of such monitoring in a pilot sample of Emergency Department (ED stroke patients. Secondary objectives included analysis of hemodynamic variability and correlation of continuous blood pressure measurements with standard measurements. Methods: This study was a secondary analysis of 7 stroke patients from a prospectively collected data set of patients that received 2 hours of hemodynamic monitoring in the ED. Stroke patients were included if hemorrhagic or ischemic stroke was confirmed by neuroimaging, and symptom onset was within 24 hours. They were excluded for the presence of a stroke mimic or transient ischemic attack. Monitoring was performed using the Nexfin device (Edwards Lifesciences, Irvine CA. Results: The mean age of the cohort was 71 ± 17 years, 43% were male, and the mean National Institute of Health Stroke Scale (NIHSS was 6.9 ± 5.5. Two patients had hemorrhagic stroke. We obtained 42,456 hemodynamic data points, including beat-to-beat blood pressure measurements with variability of 18 mmHg and cardiac indices ranging from 1.8 to 3.6 l/min/m2. The correlation coefficient between continuous blood pressure measurements with the Nexfin device and standard ED readings was 0.83. Conclusion: This exploratory investigation revealed that continuous, noninvasive monitoring in the ED is feasible in acute stroke. Further research is currently underway to determine how such monitoring may impact outcomes in stroke or replace the need for invasive monitoring. [West J Emerg Med. 2014;15(4:–0.

  2. Investigation of hemodynamics in the assisted isolated porcine heart.

    Science.gov (United States)

    Granegger, Marcus; Mahr, Stephane; Horvat, Johann; Aigner, Philipp; Roehrich, Michael; Stoiber, Martin; Plasenzotti, Roberto; Zimpfer, Daniel; Schima, Heinrich; Moscato, Francesco

    2013-12-01

    Currently, the interaction between rotary blood pumps (RBP) and the heart is investigated in silico, in vitro, and in animal models. Isolated and defined changes in hemodynamic parameters are unattainable in animal models, while the heart-pump interaction in its whole complexity cannot be modeled in vitro or in silico. The aim of this work was to develop an isolated heart setup to provide a realistic heart-pump interface with the possibility of easily adjusting hemodynamic parameters. A mock circuit mimicking the systemic circulation was developed. Eight porcine hearts were harvested using a protocol similar to heart transplantation. Then, the hearts were resuscitated using Langendorff perfusion with rewarmed, oxygenated blood. An RBP was implanted and the setup was switched to the "working mode" with the left heart and the RBP working as under physiologic conditions. Both the unassisted and assisted hemodynamics were monitored. In the unassisted condition, cardiac output was up to 9.5 l/min and dP/dtmax ranged from 521 to 3621 mmHg/s at a preload of 15 mmHg and afterload of 70 mmHg. With the RBP turned on, hemodynamics similar to heart-failure patients were observed in each heart. Mean pump flow and flow pulsatility ranged from 0 to 11 l/min. We were able to reproduce conditions with an open and closed aortic valve as well as suction events. An isolated heart setup including an RBP was developed, which combines the advantages of in silico/vitro methods and animal experiments. This tool thus provides further insight into the interaction between the heart and an RBP.

  3. Association between cerebral hemodynamic changes and neonatal hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    LIU Shuyan

    2017-10-01

    Full Text Available ObjectiveTo investigate the association between cerebral hemodynamic changes and neonatal hyperbilirubinemia. MethodsA total of 67 neonates with hyperbilirubinemia who were admitted to our hospital from January 2014 to November 2015 were enrolled as study group, and another 36 normal healthy neonates were enrolled as control group. The two groups were compared in terms of end-diastolic velocity (Vd, systolic peak velocity (Vs, mean blood flow velocity (Vm, resistance index (RI, and pulsatility index (PI, and the serum level of bilirubin and systemic symptoms were observed after treatment. The t-test was used for comparison of continuous data between groups, and a Pearson correlation analysis was also performed. ResultsAt the time of enrolment and on day 3 of treatment, the control group had significantly lower Vd, Vs, and Vm than the study group (before treatment: t=75873,81589,64600,19834,30453; day 3 of treatment: t=39476,55729,35274,6069,9382, all P<0.001. The study group had improvements in Vd, Vs, Vm, RI, and PI on day 3 of treatment. On day 5 of treatment, there were no significant differences in hemodynamic parameters between the two groups (all P>0.05. Serum level of bilirubin was positively correlated with Vd (r=0.387, P<0.001, Vs (r=0.483, P<0.001, and Vm (r=0.412, P<0.001 and negatively correlated with RI (r=-0.492, P<0.001 and PI (r=-0.497, P<0.001. ConclusionSerum level of bilirubin interacts with cerebral hemodynamics, and cerebral hemodynamic parameters can provide objective evidence for evaluating disease progression and prognosis of neonatal hyperbilirubinemia.

  4. Social stress and the polymorphic region of the serotonin reuptake transporter gene modify oestradiol-induced changes on central monoamine concentrations in female rhesus monkeys.

    Science.gov (United States)

    Asher, J; Michopoulos, V; Reding, K M; Wilson, M E; Toufexis, D

    2013-04-01

    Psychosocial stress exposure is linked to the disruption of emotional regulation that can manifest as anxiety and depression. Women are more likely to suffer from such psychopathologies than men, indicating that sex-based differences in gonadal steroids may be a key factor in the aetiology of stress-induced adverse health outcomes. Oestradiol (E2 ) positively influences mood and cognition in females, an effect likely related to the ability of E2 to modulate the serotonin and dopamine neurotransmitter systems. Furthermore, genetic variation as a result of the polymorphism in the promoter region of the gene (SLC6A4) encoding the serotonin transporter (5HTTLPR) also can influence the ability of E2 to modulate behaviour and physiology. However, it remains uncertain whether exposure to social stress interacts with the 5HTTLPR to influence E2 -induced changes in behaviour and physiology. The present study used ovariectomised adult female rhesus monkeys to investigate acute and chronic effects of E2 on central monoamine metabolite concentrations using cerobrospinal fluid sampling. We further assessed how E2 -induced changes in monoamine metabolite levels are modified by the unpredictable stress of social subordination and the 5HTTLPR polymorphism. Levels of the serotonin metabolite 5-hydroxyindoleacetic acid decreased significantly during chronic E2 treatment only in dominant females with the long promoter length of SLC6A4. Chronic administration of E2 decreased levels of the dopamine metabolite dihydrophenylacetic acid in a manner independent of the social status, 5HTTLPR genotype, or their interactions. Overall levels of dopamine and serotonin metabolites were increased in subordinate females, although this effect of social stress was not influenced by 5HTTLPR genotype. Together, these data emphasise how E2 can modulate central neurotransmitter systems and indicate that social subordination in female monkeys is a valid model for examining how chronic psychosocial stress

  5. Hemodynamic responses in rat brain during transcranial direct current stimulation: a functional near-infrared spectroscopy study.

    Science.gov (United States)

    Han, Chang-Hee; Song, Hyuna; Kang, Yong-Guk; Kim, Beop-Min; Im, Chang-Hwan

    2014-06-01

    In the present study, we monitored hemodynamic responses in rat brains during transcranial direct current stimulation (tDCS) using functional near-infrared spectroscopy (fNIRS). Seven rats received transcranial anodal stimulation with 200 μA direct current (DC) on their right barrel cortex for 10 min. The concentration changes of oxygenated hemoglobin (oxy-Hb) were continuously monitored during stimulation (10 min) and after stimulation (20 min). The trend of hemodynamic response changes was modeled using linear regression, and the relationship between incremental and decremental rates of oxy-Hb was investigated by correlation analysis. Our results showed that the oxy-Hb concentration was almost linearly increased and decreased during and after stimulation, respectively. In addition, a significant negative correlation (p < 0.05) was found between the rate of increase of oxy-Hb during stimulation and the rate of decrease of oxy-Hb after stimulation, indicating that the recovery time after tDCS may not depend on the total amount of hemodynamic changes in the stimulated brain area. Our results also demonstrated considerable individual variability in the rate of change of hemodynamic responses even with the same direct current dose to identical brain regions. This suggests that individual differences in tDCS after-effects may originate from intrinsic differences in the speed of DC stimulation "uptake" rather than differences in the total capacity of DC uptake, and thus the stimulation parameters may need to be customized for each individual in order to maximize tDCS after-effects.

  6. Reduction of global interference of scalp-hemodynamics in functional near-infrared spectroscopy using short distance probes.

    Science.gov (United States)

    Sato, Takanori; Nambu, Isao; Takeda, Kotaro; Aihara, Takatsugu; Yamashita, Okito; Isogaya, Yuko; Inoue, Yoshihiro; Otaka, Yohei; Wada, Yasuhiro; Kawato, Mitsuo; Sato, Masa-Aki; Osu, Rieko

    2016-11-01

    Functional near-infrared spectroscopy (fNIRS) is used to measure cerebral activity because it is simple and portable. However, scalp-hemodynamics often contaminates fNIRS signals, leading to detection of cortical activity in regions that are actually inactive. Methods for removing these artifacts using standard source-detector distance channels (Long-channel) tend to over-estimate the artifacts, while methods using additional short source-detector distance channels (Short-channel) require numerous probes to cover broad cortical areas, which leads to a high cost and prolonged experimental time. Here, we propose a new method that effectively combines the existing techniques, preserving the accuracy of estimating cerebral activity and avoiding the disadvantages inherent when applying the techniques individually. Our new method accomplishes this by estimating a global scalp-hemodynamic component from a small number of Short-channels, and removing its influence from the Long-channels using a general linear model (GLM). To demonstrate the feasibility of this method, we collected fNIRS and functional magnetic resonance imaging (fMRI) measurements during a motor task. First, we measured changes in oxygenated hemoglobin concentration (∆Oxy-Hb) from 18 Short-channels placed over motor-related areas, and confirmed that the majority of scalp-hemodynamics was globally consistent and could be estimated from as few as four Short-channels using principal component analysis. We then measured ∆Oxy-Hb from 4 Short- and 43 Long-channels. The GLM identified cerebral activity comparable to that measured separately by fMRI, even when scalp-hemodynamics exhibited substantial task-related modulation. These results suggest that combining measurements from four Short-channels with a GLM provides robust estimation of cerebral activity at a low cost. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Comprehensive cognitive and cerebral hemodynamic evaluation after cranioplasty

    Directory of Open Access Journals (Sweden)

    Coelho F

    2014-05-01

    Full Text Available Fernanda Coelho,1 Arthur Maynart Oliveira,2 Wellingson Silva Paiva,2 Fabio Rios Freire,1 Vanessa Tome Calado,1 Robson Luis Amorim,2 Iuri Santana Neville,2 Almir Ferreira de Andrade,2 Edson Bor-Seng-Shu,3 Renato Anghinah,1 Manoel Jacobsen Teixeira21Neurorehabilitation Group, Division of Neurology, 2Division of Neurosurgery, 3Neurosonology and Cerebral Hemodynamics Group, University of São Paulo Medical School, São Paulo, BrazilAbstract: Decompressive craniectomy is an established procedure to lower intracranial pressure and can save patients' lives. However, this procedure is associated with delayed cognitive decline and cerebral hemodynamics complications. Studies show the benefits of cranioplasty beyond cosmetic aspects, including brain protection, and functional and cerebrovascular aspects, but a detailed description of the concrete changes following this procedure are lacking. In this paper, the authors report a patient with trephine syndrome who underwent cranioplasty; comprehensive cognitive and cerebral hemodynamic evaluations were performed prior to and following the cranioplasty. The discussion was based on a critical literature review.Keywords: cranioplasty, decompressive craniotomy, perfusion CT, traumatic brain injury, cognition, neuropsychological test

  8. Quantifying the abnormal hemodynamics of sickle cell anemia

    Science.gov (United States)

    Lei, Huan; Karniadakis, George

    2012-02-01

    Sickle red blood cells (SS-RBC) exhibit heterogeneous morphologies and abnormal hemodynamics in deoxygenated states. A multi-scale model for SS-RBC is developed based on the Dissipative Particle Dynamics (DPD) method. Different cell morphologies (sickle, granular, elongated shapes) typically observed in deoxygenated states are constructed and quantified by the Asphericity and Elliptical shape factors. The hemodynamics of SS-RBC suspensions is studied in both shear and pipe flow systems. The flow resistance obtained from both systems exhibits a larger value than the healthy blood flow due to the abnormal cell properties. Moreover, SS-RBCs exhibit abnormal adhesive interactions with both the vessel endothelium cells and the leukocytes. The effect of the abnormal adhesive interactions on the hemodynamics of sickle blood is investigated using the current model. It is found that both the SS-RBC - endothelium and the SS-RBC - leukocytes interactions, can potentially trigger the vicious ``sickling and entrapment'' cycles, resulting in vaso-occlusion phenomena widely observed in micro-circulation experiments.

  9. Hemodynamic and tubular changes induced by contrast media.

    Science.gov (United States)

    Caiazza, Antonella; Russo, Luigi; Sabbatini, Massimo; Russo, Domenico

    2014-01-01

    The incidence of acute kidney injury induced by contrast media (CI-AKI) is the third cause of AKI in hospitalized patients. Contrast media cause relevant alterations both in renal hemodynamics and in renal tubular cell function that lead to CI-AKI. The vasoconstriction of intrarenal vasculature is the main hemodynamic change induced by contrast media; the vasoconstriction is accompanied by a cascade of events leading to ischemia and reduction of glomerular filtration rate. Cytotoxicity of contrast media causes apoptosis of tubular cells with consequent formation of casts and worsening of ischemia. There is an interplay between the negative effects of contrast media on renal hemodynamics and on tubular cell function that leads to activation of renin-angiotensin system and increased production of reactive oxygen species (ROS) within the kidney. Production of ROS intensifies cellular hypoxia through endothelial dysfunction and alteration of mechanisms regulating tubular cells transport. The physiochemical characteristics of contrast media play a critical role in the incidence of CI-AKI. Guidelines suggest the use of either isoosmolar or low-osmolar contrast media rather than high-osmolar contrast media particularly in patients at increased risk of CI-AKI. Older age, presence of atherosclerosis, congestive heart failure, chronic renal disease, nephrotoxic drugs, and diuretics may multiply the risk of CI-AKI.

  10. Hemodynamic stroke: A rare pitfall in cranio cervical junction surgery

    Directory of Open Access Journals (Sweden)

    Jan Frederick Cornelius

    2014-01-01

    Full Text Available Surgical C1C2-stabilization may be complicated by arterial-arterial embolism or arterial injury. Another potential complication is hemodynamic stroke. The latter might be induced in patients with poor posterior fossa collateralization (risk factor 1 when the vertebral artery (VA is compressed during reduction (risk factor 2. We report a clinical case where this rare situation occurred: A 72-year old patient was undergoing C1C2-stabilization for subluxation due to rheumatoid arthritis. Preoperative computed tomography angiography (CTA had shown poor collaterals in the posterior fossa. Furthermore, intraoperative Doppler ultrasound (US detected unilateral VA occlusion during reduction. It appeared to be a high-risk situation for hemodynamic stroke. Surgical inspection of the VA found osteofibrous compressing elements. Arterial decompression was performed resulting in the normal flow as detected by US. Subsequently, C1C2-stabilization could be realized. The clinical and radiological outcome was very favorable. In C1C2-stabilization precise analysis of preoperative CTA and intraoperative US are important to detect risk factors of hemodynamic stroke. Using these data may prevent this rare, but potentially life-threatening complication.

  11. Invasive hemodynamic monitoring in the postoperative period of cardiac surgery

    Directory of Open Access Journals (Sweden)

    Desanka Dragosavac

    1999-08-01

    Full Text Available OBJETIVE: To assess the hemodynamic profile of cardiac surgery patients with circulatory instability in the early postoperative period (POP. METHODS: Over a two-year period, 306 patients underwent cardiac surgery. Thirty had hemodynamic instability in the early POP and were monitored with the Swan-Ganz catheter. The following parameters were evaluated: cardiac index (CI, systemic and pulmonary vascular resistance, pulmonary shunt, central venous pressure (CVP, pulmonary capillary wedge pressure (PCWP, oxygen delivery and consumption, use of vasoactive drugs and of circulatory support. RESULTS: Twenty patients had low cardiac index (CI, and 10 had normal or high CI. Systemic vascular resistance was decreased in 11 patients. There was no correlation between oxygen delivery (DO2 and consumption (VO2, p=0.42, and no correlation between CVP and PCWP, p=0.065. Pulmonary vascular resistance was decreased in 15 patients and the pulmonary shunt was increased in 19. Two patients with CI < 2L/min/m² received circulatory support. CONCLUSION: Patients in the POP of cardiac surgery frequently have a mixed shock due to the systemic inflammatory response syndrome (SIRS. Therefore, invasive hemodynamic monitoring is useful in handling blood volume, choice of vasoactive drugs, and indication for circulatory support.

  12. Fenestrated Stent Graft Repair of Abdominal Aortic Aneurysm: Hemodynamic Analysis of the Effect of Fenestrated Stents on the Renal Arteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhonghua; Chaichana, Thanapong [Curtin University of Technology, Perth (Australia)

    2010-02-15

    We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method. Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients' treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks. Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair.

  13. Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device.

    Science.gov (United States)

    Wang, Chao; Tian, Zhongbin; Liu, Jian; Jing, Linkai; Paliwal, Nikhil; Wang, Shengzhang; Zhang, Ying; Xiang, Jianping; Siddiqui, Adnan H; Meng, Hui; Yang, Xinjian

    2016-07-02

    The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD). In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents. Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model. This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.

  14. Changes in regional brain monoaminergic activity and temporary down-regulation in stress response from dietary supplementation with l-tryptophan in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Basic, D.; Schjolden, J.; Krogdahl, A.

    2013-01-01

    or four times the Trp levels in commercial feed, last in juvenile Atlantic cod (Gadus morhua) when the fish are reintroduced to a diet with standard amino acid composition. We also wanted to determine whether Trp supplementation induced changes in brain monoaminergic neurochemistry in those forebrain...... structures innervated by DA- and 5-HTergic neurons, by measuring regional activity of DA and 5-HT in the lateral pallial regions (Dl) of the telencephalon and nucleus lateralis tuberis (NLT) of the hypothalamus. Dietary Trp resulted in a dose-dependent suppression in plasma cortisol among fish exposed...... to confinement stress on the first day following experimental diet; however, such an effect was not observed at 2 or 6 d after Trp treatment. Feeding the fish with moderate Trp doses also evoked a general increase in DA and 5-HT-ergic activity, suggesting that these neural circuits within the NLT and Dl may...

  15. Regional differences in the expression of brain-derived neurotrophic factor (BDNF) pro-peptide, proBDNF and preproBDNF in the brain confer stress resilience.

    Science.gov (United States)

    Yang, Bangkun; Yang, Chun; Ren, Qian; Zhang, Ji-Chun; Chen, Qian-Xue; Shirayama, Yukihiko; Hashimoto, Kenji

    2016-12-01

    Using learned helplessness (LH) model of depression, we measured protein expression of brain-derived neurotrophic factor (BDNF) pro-peptide, BDNF precursors (proBDNF and preproBDNF) in the brain regions of LH (susceptible) and non-LH rats (resilience). Expression of preproBDNF, proBDNF and BDNF pro-peptide in the medial prefrontal cortex of LH rats, but not non-LH rats, was significantly higher than control rats, although expression of these proteins in the nucleus accumbens of LH rats was significantly lower than control rats. This study suggests that regional differences in conversion of BDNF precursors into BDNF and BDNF pro-peptide by proteolytic cleavage may contribute to stress resilience.

  16. Exposure of Induced Pluripotent Stem Cell-Derived Vascular Endothelial and Smooth Muscle Cells in Coculture to Hemodynamics Induces Primary Vascular Cell-Like Phenotypes.

    Science.gov (United States)

    Collado, Maria S; Cole, Banumathi K; Figler, Robert A; Lawson, Mark; Manka, David; Simmers, Michael B; Hoang, Steve; Serrano, Felipe; Blackman, Brett R; Sinha, Sanjay; Wamhoff, Brian R

    2017-08-01

    Human induced pluripotent stem cells (iPSCs) can be differentiated into vascular endothelial (iEC) and smooth muscle (iSMC) cells. However, because iECs and iSMCs are not derived from an intact blood vessel, they represent an immature phenotype. Hemodynamics and heterotypic cell:cell communication play important roles in vascular cell phenotypic modulation. Here we tested the hypothesis that hemodynamic exposure of iECs in coculture with iSMCs induces an in vivo-like phenotype. iECs and iSMCs were cocultured under vascular region-specific blood flow hemodynamics, and compared to hemodynamic cocultures of blood vessel-derived endothelial (pEC) and smooth muscle (pSMC) cells. Hemodynamic flow-induced gene expression positively correlated between pECs and iECs as well as pSMCs and iSMCs. While endothelial nitric oxide synthase 3 protein was lower in iECs than pECs, iECs were functionally mature as seen by acetylated-low-density lipoprotein (LDL) uptake. SMC contractile protein markers were also positively correlated between pSMCs and iSMCs. Exposure of iECs and pECs to atheroprone hemodynamics with oxidized-LDL induced an inflammatory response in both. Dysfunction of the transforming growth factor β (TGFβ) pathway is seen in several vascular diseases, and iECs and iSMCs exhibited a transcriptomic prolife similar to pECs and pSMCs, respectively, in their responses to LY2109761-mediated transforming growth factor β receptor I/II (TGFβRI/II) inhibition. Although there are differences between ECs and SMCs derived from iPSCs versus blood vessels, hemodynamic coculture restores a high degree of similarity in their responses to pathological stimuli associated with vascular diseases. Thus, iPSC-derived vascular cells exposed to hemodynamics may provide a viable system for modeling rare vascular diseases and testing new therapeutic approaches. Stem Cells Translational Medicine 2017;6:1673-1683. © 2017 The Authors Stem Cells Translational Medicine published by Wiley

  17. [Mediator effect analysis of the trait coping style on job stress and fatigue of the military personnel stationed in plateau and high cold region].

    Science.gov (United States)

    Zhang, J J; Jia, J M; Tao, N; Song, Z X; Ge, H; Jiang, Y; Tian, H; Qiu, E C; Tang, J H; Liu, J W

    2017-03-20

    Objective: To investigate the fatigue status of military personnel stationed in plateau and high cold region, and to analyze the mediator effect of trait coping style on job stress and fatigue. Methods: In October 2010, with the method of cluster random sampling survey, 531 military personnel stationed in plateau and high cold region were chosen as subject. The fatigue status were evaluated by the Chinese version multidimensional fatigue inventory (MFI-20) , job stress were evaluated by the Job Stress Survey (JSS) , and trait coping style were evaluated by the Trait Coping Style Questionnaire (TCSQ) . Results: According to the information of different population characteristics, mean rank of physical fatigue about the urban (town) group were higher than that of rural group (Z=-2.200, Pfatigue scores about the urban (town) group were higher than that of rural group (Z=-3.026, Pfatigue about the up or equal 20-years old age group were higher than that of below 20-years old age group (Z=-4.045, Pfatigue about the up or equal 20-years old age group were higher than that of below 20-years old age group (Z=-2.879, Pfatigue scores about the up or equal 20-years old age group were higher than that of below 20-years old age group (Z=-3.647, Pfatigue scores were significant statistical difference among the military officers, sergeancy and soldier group (F=14.711, Pfatigue (r(s)=0.129) , reduced activity (r(s)=0.123) , reduced motivation (r(s)=0.149) and general fatigue (r(s)=0.174) respectively, the score of organizational support lack strength were positively correlated with the score of physical fatigue (r(s)=0.090) , reduced activity (r(s)=0.098) , reduced motivation (r(s)=0.099) and general fatigue (r(s)=0.130) respectively. The mediator effect of negative coping style on the job stress and fatigue was 0.013 (Pfatigue statuses of the urban (town) group and the up or equal 20-years old age group are poor, and the negative coping style plays mediator effect on the job

  18. Metabolic changes assessed by MRS accurately reflect brain function during drug-induced epilepsy in mice in contrast to fMRI-based hemodynamic readouts.

    Science.gov (United States)

    Seuwen, Aline; Schroeter, Aileen; Grandjean, Joanes; Rudin, Markus

    2015-10-15

    Functional proton magnetic resonance spectroscopy (1H-MRS) enables the non-invasive assessment of neural activity by measuring signals arising from endogenous metabolites in a time resolved manner. Proof-of-principle of this approach has been demonstrated in humans and rats; yet functional 1H-MRS has not been applied in mice so far, although it would be of considerable interest given the many genetically engineered models of neurological disorders established in this species only. Mouse 1H-MRS is challenging as the high demands on spatial resolution typically result in long data acquisition times not commensurable with functional studies. Here, we propose an approach based on spectroscopic imaging in combination with the acquisition of the free induction decay to maximize signal intensity. Highly resolved metabolite maps have been recorded from mouse brain with 12 min temporal resolution. This enabled monitoring of metabolic changes following the administration of bicuculline, a GABA-A receptor antagonist. Changes in levels of metabolites involved in energy metabolism (lactate and phosphocreatine) and neurotransmitters (glutamate) were investigated in a region-dependent manner and shown to scale with the bicuculline dose. GABAergic inhibition induced spectral changes characteristic for increased neurotransmitter turnover and oxidative stress. In contrast to metabolic readouts, BOLD and CBV fMRI responses did not scale with the bicuculline dose indicative of the failure of neurovascular coupling. Nevertheless fMRI measurements supported the notion of increased oxidative stress revealed by functional MRS. Hence, the combined analysis of metabolic and hemodynamic changes in response to stimulation provides complementary insight into processes associated with neural activity. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress in rats with streptozotocin-induced type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Sang Gun Lee

    2015-01-01

    Full Text Available In this study, we investigated the effects of streptozotocin-induced type 1 diabetes on antioxidant-like protein-1 immunoreactivity, protein carbonyl levels, and malondialdehyde formation, a marker for lipid peroxidation, in the hippocampus. For this study, streptozotocin (75 mg/kg was intraperitoneally injected into adult rats to induce type 1 diabetes. The three experimental parameters were determined at 2, 3, 4 weeks after streptozotocin treatment. Fasting blood glucose levels significantly increased by 20.7-21.9 mM after streptozotocin treatment. The number of antioxidant-like protein-1 immunoreactive neurons significantly decreased in the hippocampal CA1 region, but not the dentate gyrus, 3 weeks after streptozotocin treatment compared to the control group. Malondialdehyde and protein carbonyl levels, which are modified by oxidative stress, significantly increased with a peak at 3 weeks after malondialdehyde treatment, and then decreased 4 weeks after malondialdehyde treatment. These results suggest that neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress 3 weeks after malondialdehyde treatment.

  20. Hemodynamic effects of developmental venous anomalies with and without cavernous malformations.

    Science.gov (United States)

    Sharma, A; Zipfel, G J; Hildebolt, C; Derdeyn, C P

    2013-09-01

    Association between developmental venous anomalies is well known, but remains unexplained. Our aim was to study possible hemodynamic differences around developmental venous anomalies with and without cavernous malformations. In this prospective study approved by the institutional review board, PWI was performed in 24 patients with 25 DVAs (10 with and 15 without CMs) who consented to participate. We calculated relative cerebral blood volume, relative cerebral blood flow, and relative mean transit time for the brain surrounding the DVA tributaries in reference to contralateral mirror image locations. Corresponding control values (cCBV, cCBF, and cMTT) were generated in a similar fashion for remote ipsilateral regions with normal venous drainage, also in reference to contralateral mirror image locations. Perfusion parameters for DVAs and control regions were tested for differences between groups with the t test for independent or paired samples (or the nonparametric equivalents). Similar testing was done for perfusion parameters for DVAs with and without CMs. Normal-appearing brain surrounding DVAs showed increased rCBV (median = 2.98; range = 1.39-6.61), increased rCBF (median = 2.00, range = 0.79-4.43), and increased rMTT (mean = 1.46; 95% confidence interval, 1.32-1.59). These were significantly higher than median cCBV (0.99; 95% confidence interval, 0.89-1.06; P < .01), median cCBF (1.00; 95% confidence interval, 0.94-1.27; P < .01), and mean cMTT (1.00; 95% confidence interval, 0.98-1.02; P < .01), respectively. Mean rMTT (1.70; 95% confidence interval, 1.46-1.93) for DVAs with CMs was higher than mean rMTT (1.29; 95% confidence interval, 1.19-1.40; P < .01) for DVAs without CMs. DVAs are strongly associated with altered hemodynamics. Significant differences in these hemodynamic alterations for DVAs with and without CMs suggest their possible role in the formation of CMs.

  1. The effect of aneurismal-wall mechanical properties on patient-specific hemodynamic simulations: two clinical case reports

    Science.gov (United States)

    Chen, Jialiang; Wang, Shengzhang; Ding, Guanghong; Yang, Xinjian; Li, Haiyun

    2009-10-01

    Hemodynamic factors such as the wall shear stress play an important role in the pathogenesis and treatment of cerebral aneurysms. In present study, we apply computational fluid-structure interaction analyses on cerebral aneurysms with two different constitutive relations for aneurismal wall in order to investigate the effect of the aneurismal wall mechanical properties on the simulation results. We carry out these analyses by using two patient-specific models of cerebral aneurysms of different sizes located in different branches of the circle of Willis. The models are constructed from 3D rotational angiography image data and blood flow dynamics is studied under physiologically representative waveform of inflow. From the patient models analyzed in this investigation, we find that the deformations of cerebral aneurysms are very small. But due to the nonlinear character of the Navier-Stokes equations, these small deformations could have significant influences on the flow characteristics. In addition, we find that the aneurismal-wall mechanical properties have great effects on the deformation distribution of the aneurysm, which also affects the wall shear stress distribution and flow patterns. Therefore, how to define a proper constitutive relation for aneurismal wall should be considered carefully in the hemodynamic simulation.

  2. Using regional moment tensors to constrain the kinematics and stress evolution of the 2010–2013 Canterbury earthquake sequence, South Island, New Zealand

    Science.gov (United States)

    Herman, Matthew W.; Herrmann, Robert B.; Benz, Harley M.; Furlong, Kevin P.

    2014-01-01

    On September 3, 2010, a MW 7.0 (U.S. Geological Survey moment magnitude) earthquake ruptured across the Canterbury Plains in South Island, New Zealand. Since then, New Zealand GNS Science has recorded over 10,000 aftershocks ML 2.0 and larger, including three destructive ~ MW 6.0 earthquakes near Christchurch. We treat the Canterbury earthquake sequence as an intraplate earthquake sequence, and compare its kinematics to an Andersonian model for fault slip in a uniform stress field. We determined moment magnitudes and double couple solutions for 150 earthquakes having MW 3.7 and larger through the use of a waveform inversion technique using data from broadband seismic stations on South Island, New Zealand. The majority (126) of these double couple solutions have strike-slip focal mechanisms, with right-lateral slip on ENE fault planes or equivalently left-lateral slip on SSE fault planes. The remaining focal mechanisms indicate reverse faulting, except for two normal faulting events. The strike-slip segments have compatible orientations for slip in a stress field with a horizontal σ1 oriented ~ N115°E, and horizontal σ3. The preference for right lateral strike-slip earthquakes suggests that these structures are inherited from previous stages of deformation. Reverse slip is interpreted to have occurred on previously existing structures in regions with an absence of existing structures optimally oriented for strike-slip deformation. Despite the variations in slip direction and faulting style, most aftershocks had nearly the same P-axis orientation, consistent with the regional σ1. There is no evidence for significant changes in these stress orientations throughout the Canterbury earthquake sequence.

  3. Occupational exposure to ionizing radiation from the perspective of nursing professionals in hemodynamics

    Directory of Open Access Journals (Sweden)

    Adriana Martins Gallo

    2013-05-01

    Full Text Available In order to identify the security measures taken and the control of occupational exposure to ionizing radiation in units of hemodynamic, from the perspective of nursing, this quantitative descriptive study was developed during January and February, 2011. A check-list of binary responses (yes / no was made based on the legislation and updated literature and it was applied in four hospitals in the northern region of Paraná State. The analysis of the data showed that 29 employees have knowledge about occupational exposure and apply barrier methods effectively to minimize doses of ionizing radiation. The data also showed that employees are participating in ongoing updating on the subject, and that they claim that this participation has a positive effect so that the occupational exposure occurs consciously, and also, the workers did not refuse to participate in any action facing their individual protection.

  4. Amplitude variability over trials in hemodynamic responses in adolescents with ADHD

    DEFF Research Database (Denmark)

    Sørensen, L; Eichele, T; van Wageningen, H

    2016-01-01

    levels were more complex. Performance IIV correlated significantly with variability of HRs in both networks. These results suggest that assessment of trial-to-trial HR variability in ADHD provides information beyond that detectable through analysis of behavioral data and average brain activation levels...... variable response times. In this study, we asked whether ADHD IIV in reaction time on a commonly-used test of attention might be related to variation in hemodynamic responses (HRs) observed trial-to-trial. Based on previous studies linking IIV to regions within the "default mode" network (DMN), we...... predicted that adolescents with ADHD would have higher HR variability in the DMN compared with controls, and this in turn would be related to behavioral IIV. We also explored the influence of social anxiety on HR variability in ADHD as means to test whether higher arousal associated with high trait anxiety...

  5. Coronary artery plaque formation at coronary CT angiography: morphological analysis and relationship to hemodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Enrico, Benedetta [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Universita' Cattolica del Sacro Cuore, Department of Radiology, Rome (Italy); Suranyi, Pal; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Thilo, Christian; Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Bonomo, Lorenzo [Universita' Cattolica del Sacro Cuore, Department of Radiology, Rome (Italy)

    2009-04-15

    We aimed to demonstrate that coronary CT angiography (cCTA) can be used to non-invasively study the effect of hemodynamic factors in the pathophysiology of plaque formation. cCTA data of 73 patients were analyzed. All detected plaques were classified according to location (bifurcation, non-branching segment), configuration (eccentric, concentric), orientation (myocardial, lateral, epicardial side of the vessel wall), and composition (calcified, mixed, non-calcified). Bifurcation lesions were further characterized using the Medina classification. Of 382 plaques, 8.1% were in the LM, 46.3% in the LAD, 18.3% in the LCx, and 25.9% in the RCA. Also, 25.1% were completely calcified, 72.3% were mixed, and 2.6% were purely non-calcified. Of the plaques, 51.3% were bifurcation lesions. The most frequent (40%) Medina pattern was 1.1.0 (lesion starts before, extends beyond bifurcation, sparing the side branch). Eighty percent of plaques were eccentric. A significant (p < 0.01) majority (55%) were on the myocardial side, while 17.3% were lateral, and 27.7% epicardial. Of all non-calcified and mixed plaques, 45.1% (p < 0.01) were myocardial, whereas only 14.3% were lateral, 20.6% epicardial, and 19.9% concentric. We conclude that cCTA can non-invasively study the effect of vascular hemodynamics, such as turbulent flow (bifurcations) and low shear stress (myocardial vessel wall), on the distribution and composition of atherosclerotic plaque deposition. (orig.)

  6. Pericentromeric regions are refractory to prompt repair after replication stress-induced breakage in HPV16 E6E7-expressing epithelial cells.

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    Wen Deng

    Full Text Available Chromosomal instability is the major form of genomic instability in cancer cells. Amongst various forms of chromosomal instability, pericentromeric or centromeric instability remains particularly poorly understood. In the present study, we found that pericentromeric instability, evidenced by dynamic formation of pericentromeric or centromeric rearrangements, breaks, deletions or iso-chromosomes, was a general phenomenon in human cells immortalized by expression of human papillomavirus type 16 E6 and E7 (HPV16 E6E7. In particular, for the first time, we surprisingly found a dramatic increase in the proportion of pericentromeric chromosomal aberrations relative to total aberrations in HPV16 E6E7-expressing cells 72 h after release from aphidicolin (APH-induced replication stress, with pericentromeric chromosomal aberrations becoming the predominant type of structural aberrations (~70% of total aberrations. In contrast, pericentromeric aberrations accounted for only about 20% of total aberrations in cells at the end of APH treatment. This increase in relative proportion of pericentromeric aberrations after release from APH treatment revealed that pericentromeric breaks induced by replication stress are refractory to prompt repair in HPV16 E6E7-expressing epithelial cells. Telomerase-immortalized epithelial cells without HPV16 E6E7 expression did not exhibit such preferential pericentromeric instability after release from APH treatment. Cancer development is often associated with replication stress. Since HPV16 E6 and E7 inactivate p53 and Rb, and p53 and Rb pathway defects are common in cancer, our finding that pericentromeric regions are refractory to prompt repair after replication stress-induced breakage in HPV16 E6E7-expressing cells may shed light on mechanism of general pericentromeric instability in cancer.

  7. Sex-specific effects of prenatal chronic mild stress on adult spatial learning capacity and regional glutamate receptor expression profiles.

    Science.gov (United States)

    Wang, Yan; Ma, Yuchao; Hu, Jingmin; Zhang, Xinxin; Cheng, Wenwen; Jiang, Han; Li, Min; Ren, Jintao; Zhang, Xiaosong; Liu, Mengxi; Sun, Anji; Wang, Qi; Li, Xiaobai

    2016-07-01

    Both animal experiments and clinical studies have demonstrated that prenatal stress can cause cognitive disorders in offspring. To explore the scope of these deficits and identify potential underlying mechanisms, we examined the spatial learning and memory performance and glutamate receptor (GluR) expression patterns of adult rats exposed to prenatal chronic mild stress (PCMS). Principal component analysis (PCA) was employed to reveal the interrelationships among spatial learning indices and GluR expression changes. Female PCMS-exposed offspring exhibited markedly impaired spatial learning and memory in the Morris water maze (MWM) task compared to control females, while PCMS-exposed males showed better initial spatial learning in the MWM compared to control males. PCMS also altered basal and post-MWM glutamate receptor expression patterns, but these effects differed markedly between sexes. Male PCMS-exposed offspring exhibited elevated basal expression of NR1, mGluR5, and mGluR2/3 in the prefrontal cortex (PFC), whereas females showed no basal expression changes. Following MWM training, PCMS-exposed males expressed higher NR1 in the PFC and mammillary body (MB), higher mGluR2/3 in PFC, and lower NR2B in the hippocampus (HIP), PFC, and MB compared to unstressed MWM-trained males. Female PCMS-exposed offspring showed strongly reduced NR1 in MB and NR2B in the HIP, PFC, and MB, and increased mGluR2/3 in PFC compared to unstressed MWM-trained females. This is the first report suggesting that NMDA subunits in the MB are involved in spatial learning. Additionally, PCA further suggests that the NR1-NR2B form is the most important for spatial memory formation. These results reveal long-term sex-specific effects of PCMS on spatial learning and memory performance in adulthood and implicate GluR expression changes within HIP, PFC, and MB as possible molecular mechanisms underlying cognitive dysfunction in offspring exposed to prenatal stress. Copyright © 2016 Elsevier Inc

  8. Hemodynamic and clinical onset in patients with hereditary pulmonary arterial hypertension and BMPR2 mutations

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    Tiede Henning

    2011-07-01

    Full Text Available Abstract Background Mutations in the bone morphogenetic protein receptor 2 (BMPR2 gene can lead to idiopathic pulmonary arterial hypertension (IPAH. This study prospectively screened for BMPR2 mutations in a large cohort of PAH-patients and compared clinical features between BMPR2 mutation carriers and non-carriers. Methods Patients have been assessed by right heart catheterization and genetic testing. In all patients a detailed family history and pedigree analysis have been obtained. We compared age at diagnosis and hemodynamic parameters between carriers and non-carriers of BMPR2 mutations. In non-carriers with familial aggregation of PAH further genes/gene regions as the BMPR2 promoter region, the ACVRL1, Endoglin, and SMAD8 genes have been analysed. Results Of the 231 index patients 22 revealed a confirmed familial aggregation of the disease (HPAH, 209 patients had sporadic IPAH. In 49 patients (86.3% of patients with familial aggregation and 14.3% of sporadic IPAH mutations of the BMPR2 gene have been identified. Twelve BMPR2 mutations and 3 unclassified sequence variants have not yet been described before. Mutation carriers were significantly younger at diagnosis than non-carriers (38.53 ± 12.38 vs. 45.78 ± 11.32 years, p Conclusion This study identified in a large prospectively assessed cohort of PAH- patients new BMPR2 mutations, which have not been described before and confirmed previous findings that mutation carriers are younger at diagnosis with a more severe hemodynamic compromise. Thus, screening for BMPR2 mutations may be clinically useful.

  9. Effect of fiberoptic intubation on myocardial ischemia and hormonal stress response in diabetics with ischemic heart disease

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    Nashwa Nabil Mohamed

    2014-01-01

    Conclusion: The optimum use of fiberoptic bronchoscope with avoidance of jaw thrust maneuver attenuates the hemodynamic response to intubation which is beneficial in diabetic patients with ischemic heart disease. Stress response hormones showed no statistically significant difference between groups.

  10. The Diagnosis and Hemodynamic Monitoring of Circulatory Shock: Current and Future Trends

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    Hendy Adham

    2016-07-01

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